Papers - AZUMA Minako
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Metastatic Cardiac Tumor Mimicking Coronary Artery Aneurysm on Postmortem Computed Tomography. Reviewed
Shinkawa N, Yamada R, Azuma M, Shinkawa N, Yukawa N
The American journal of forensic medicine and pathology 2025.3
Language：English Publishing type：Research paper (scientific journal)
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Oguri N., Gi T., Nakamura E., Maekawa K., Furukoji E., Okawa H., Kouyama S., Horiuchi S., Sawaguchi A., Sakae T., Azuma M., Asada Y., Yamashita A.
Research and Practice in Thrombosis and Haemostasis 9 ( 2 ) 2025.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Research and Practice in Thrombosis and Haemostasis
Background: Novel anticoagulants targeting coagulation factor (F)XI/activated FXI (FXIa) are currently under development. However, whether FXI is present in human deep vein thrombosis (DVT) and whether FXIa and activated FX (FXa) play different roles in venous thrombus formation and hemostasis remain unclear. Objectives: To determine the presence of FXI in DVT and the effects of direct oral FXIa and FXa inhibitors on venous thrombus formation and hemostasis in rabbits and on in vitro thrombus formation. Methods: We immunohistochemically assessed FXI localization in human-aspirated DVT (n = 15). Additionally, we compared thrombus formation induced by endothelial denudation and stenosis or stasis in the jugular vein and skin bleeding time and volume between rabbits treated with direct FXIa inhibitors (ONO-1600586) and FXa inhibitors (rivaroxaban). Ex vivo rabbit and human blood were perfused in a flow chamber under low-shear rates (70/s). Results: FXI was localized in all DVT, predominantly in fibrin-rich areas. The FXI immunopositive area in the nonorganizing area was greater than that in the organizing area. Although FXIa and FXa inhibitors comparably inhibited venous thrombus formation, FXIa inhibitors did not affect bleeding time or volume in rabbits. FXIa or FXa inhibitors mildly or strongly inhibited fibrin formation at low-shear rates, respectively. Furthermore, the FXIa inhibitor suppressed human FXIa activity, thrombin generation, and fibrin formation during perfusion. Conclusion: The pathologic findings of human DVT suggest FXI's role in human DVT. FXIa inhibitors may inhibit less fibrin formation than FXa inhibitors and may explain the minor role of FXIa in hemostasis.
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Expression of fibroblast activation protein-α in human deep vein thrombosis Reviewed
Oguri N., Gi T., Nakamura E., Furukoji E., Goto H., Maekawa K., Tsuji A.B., Nishii R., Aman M., Moriguchi-Goto S., Sakae T., Azuma M., Yamashita A.
Thrombosis Research 241 109075 2024.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Thrombosis Research
Background: Fibroblast activation protein-α (FAP), a type-II transmembrane serine protease, is associated with wound healing, cancer-associated fibroblasts, and chronic fibrosing diseases. However, its expression in deep vein thrombosis (DVT) remains unclear. Therefore, this study investigated FAP expression and localization in DVT. Methods: We performed pathological analyses of the aspirated thrombi of patients with DVT (n = 14), classifying thrombotic areas in terms of fresh, cellular lysis, and organizing reaction components. The organizing reaction included endothelialization and fibroblastic reaction. We immunohistochemically examined FAP-expressed areas and cells, and finally analyzed FAP expression in cultured dermal fibroblasts. Results: All the aspirated thrombi showed a heterogeneous mixture of at least two of the three thrombotic areas. Specifically, 83 % of aspirated thrombi showed fresh and organizing reaction components. Immunohistochemical expression of FAP was restricted to the organizing area. Double immunofluorescence staining showed that FAP in the thrombi was mainly expressed in vimentin-positive or α-smooth muscle actin-positive fibroblasts. Some CD163-positive macrophages expressed FAP. FAP mRNA and protein levels were higher in fibroblasts with low-proliferative activity cultured under 0.1 % fetal bovine serum (FBS) than that under 10 % FBS. Fibroblasts cultured in 10 % FBS showed a significant decrease in FAP mRNA levels following supplementation with hemin, but not with thrombin. Conclusions: The heterogeneous composition of venous thrombi suggests a multistep thrombus formation process in human DVT. Further, fibroblasts or myofibroblasts may express FAP during the organizing process. FAP expression may be higher in fibroblasts with low proliferative activity.
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Sugita C., Maekawa K., Gi T., Oguri N., Nakamura E., Furukoji E., Azuma M., Asada Y., Yamashita A.
Thrombosis Research 238 185 - 196 2024.6
Language：English Publishing type：Research paper (scientific journal) Publisher：Thrombosis Research
Background: Plaque erosion, a type of coronary atherothrombosis, involves superficial injury to smooth muscle cell (SMC)-rich plaques. Elevated levels of coagulation factor VIII (FVIII) correlate with an increased ischemic heart disease risk. FVIII may contribute to thrombus formation on eroded plaques. Aims: We aimed to elucidate the role of elevated FVIII in arterial thrombus formation within SMC-rich neointima in rabbits. Methods and results: We assessed the effect of recombinant human FVIII (rFVIII) on blood coagulation in vitro and platelet aggregation ex vivo. An SMC-rich neointima was induced through balloon injury to the unilateral femoral artery. Three weeks after the first balloon injury, superficial erosive injury and thrombus formation were initiated with a second balloon injury of the bilateral femoral arteries 45 min after the administration of rFVIII (100 IU/kg) or saline. The thrombus area and contents were histologically measured 15 min after the second balloon injury. rFVIII administration reduced the activated partial thromboplastin time and augmented botrocetin-induced, but not collagen- or adenosine 5′-diphosphate-induced, platelet aggregation. While rFVIII did not influence platelet-thrombus formation in normal intima, it increased thrombus formation on SMC-rich neointima post-superficial erosive injury. Enhanced immunopositivity for glycoprotein IIb/IIIa and fibrin was observed in rFVIII-administered SMC-rich neointima. Neutrophil count in the arterial thrombus on the SMC-rich neointima correlated positively with thrombus size in the control group, unlike the rFVIII group. Conclusions: Increased FVIII contributes to thrombus propagation within erosive SMC-rich neointima, highlighting FVIII's potential role in plaque erosion-related atherothrombosis.
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Uchimura R., Khant Z.A., Hayashi H., Nagayama Y., Uetani H., Kaku Y., Nagatomo T., Tamura Y., Yokogami K., Mukasa A., Kiyosue H., Azuma M., Hirai T.
Journal of Computer Assisted Tomography 2024
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography
Objective Discriminating between hemorrhage and iodine extravasation can pose challenges in conventional computed tomography (CCT) images following preoperative embolization for meningioma. This study aimed to assess the efficacy of dual-energy computed tomography (DECT) in differentiating hemorrhage from iodine extravasation after preoperative embolization for meningioma. Methods Twenty-one consecutive meningioma patients who underwent CCT before and DECT immediately after preoperative embolization were included in this study. Two independent observers conducted qualitative assessments on CCT and virtual noncontrast (VNC) images and iodine maps (IMs) to differentiate between hemorrhage and iodine extravasation. One observer recorded CT values of hemorrhage and iodine extravasation on CCT and VNC images. The ratio of maximum attenuation to minimum attenuation on VNC images was defined as the VNC ratio. Statistical analysis included Kappa (κ) statistics, unpaired t tests, and receiver operating characteristic (ROC) analysis. Results Interobserver agreement for qualitative assessment was fair (κ = 0.231) for CCT alone and good (κ = 0.723) for CCT plus VNC imaging and IM. The addition of VNC imaging and IM to CCT improved differential confidence in 16 (76%) and 18 (86%) cases of the two observers, respectively, increasing the area under the receiver operating characteristic curve (AUROC) from 0.868 to 0.895 and 0.658 to 0.947, respectively. At a cutoff value of 1.527, the VNC ratio was significantly higher for hemorrhage than iodine extravasation (P < 0.05), with the highest diagnostic performance (AUROC, 1). Conclusions DECT with VNC imaging and IM is useful for differentiating hemorrhage from iodine extravasation in meningiomas with preoperative embolization.
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A Follow-up Study of National Survey on Safety Management at MR Imaging Facilities in Japan
AZUMA Minako, DOI Tsukasa, TAKAHASHI Mitsuyuki, HATA Hirofumi, UEYAMA Tsuyoshi, TAKAHASHI Junji, SAKAI Kazuyuki, OYAMA-MANABE Noriko, HATA Junichi, KATAOKA Masako, KURODA Kagayaki, IJICHI Shinpei, AOKI Shigeki, HIRAI Toshinori
Japanese Journal of Magnetic Resonance in Medicine 43 ( 4 ) 144 - 173 2023.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine
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Usefulness of Voxel-Based Quantification (VBQ) Smoothing in Relaxation Time Mapping
Fukunaga Kota, Fujiwara Yasuhiro, Enzaki Masahiro, Komi Masanori, Hirai Toshinori, Azuma Minako
Japanese Journal of Radiological Technology 79 ( 9 ) 913 - 922 2023.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Radiological Technology
<i>Purpose</i>: Voxel-based quantification (VBQ) smoothing is a technique used to smooth quantitative parametric maps in the Montreal Neurological Institute standard space. Although VBQ smoothing could suppress changes in quantitative values at tissue boundaries, its effectiveness on relaxation time (T<sub>1</sub> and T<sub>2</sub> values and proton density PD) maps has not been investigated. The purpose of this study was to clarify the usefulness of VBQ smoothing in relaxation time mapping. <i>Method</i>: T<sub>1</sub> and T<sub>2</sub> values and PD maps of the brains of 20 healthy participants were obtained using a two-dimensional multi-dynamic multi-echo sequence. VBQ and Gaussian smoothing were applied to the relaxation time maps by varying the kernel size by 1 mm from 1 to 6 mm. Changes in relaxation time before and after VBQ and Gaussian smoothing for the putamen, caudate nucleus, substantia nigra, and corpus callosum on the relaxation time maps were evaluated. <i>Result</i>: The changes in relaxation time after VBQ smoothing application were smaller than those in that after Gaussian smoothing application. Although the differences in the relaxation time for all tissues before and after VBQ and Gaussian smoothing applications increased with increasing kernel size for all relaxation times for both methods, the changes in the relaxation time for VBQ smoothing were smaller than those in that for Gaussian smoothing. <i>Conclusion</i>: VBQ smoothing can suppress the change in the relaxation time on the boundary of the tissue and is thus a useful smoothing technique in relaxation time mapping.
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Fukunaga Kota, Enzaki Masahiro, Komi Masanori, Azuma Minako, Hirai Toshinori, Fujiwara Yasuhiro
Japanese Journal of Radiological Technology 79 ( 7 ) 663 - 673 2023.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Radiological Technology
<i>Purpose</i>: Three-dimensional (3D) quantification using an interleaved Look-Locker acquisition sequence with a T<sub>2</sub> preparation pulse (QALAS) is a quantitative sequence used to measure relaxation times. The accuracy of the relaxation time measurement of 3D-QALAS at 3.0 T and the bias of 3D-QALAS have not yet been assessed. The purpose of this study was to clarify the accuracy of the relaxation time measurements using 3D-QALAS at 3.0 T MRI. <i>Methods</i>: The accuracy of the T<sub>1</sub> and T<sub>2</sub> values for 3D-QALAS was evaluated using a phantom. Subsequently, the T<sub>1</sub> and T<sub>2</sub> values and proton density of the brain parenchyma in healthy subjects were measured using 3D-QALAS and compared with those of 2D multi-dynamic multi-echo (MDME). <i>Results</i>: In the phantom study, the average T<sub>1</sub> value of 3D-QALAS was 8.3% prolonged than that for conventional inversion recovery spin-echo; the average T<sub>2</sub> value for 3D-QALAS was 18.4% shorter than that for multi-echo spin-echo. The in vivo assessment showed that the mean T<sub>1</sub> and T<sub>2</sub> values and PD for 3D-QALAS were prolonged by 5.3%, shortened by 9.6%, and increased by 7.0%, respectively, compared with those for 2D-MDME. <i>Conclusion</i>: Although 3D-QALAS at 3.0 T has high accuracy T<sub>1</sub> value, which is less than 1000 ms, the T<sub>1</sub> value could be overestimated for tissues with it longer than that T<sub>1</sub> value. The T<sub>2</sub> value for 3D-QALAS could be underestimated for tissues with T<sub>2</sub> values, and this tendency increases with longer T<sub>2</sub> values.
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A clear presentation of intracranial hypostasis on PMCT Reviewed
Shinkawa N., Imada M., Azuma M., Shinkawa N., Yukawa N.
Journal of Forensic and Legal Medicine 97 102540 2023.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Forensic and Legal Medicine
Intracranial hypostasis is a common postmortem change evident on postmortem CT (PMCT), but can be readily misinterpreted as subdural hematoma by inexperienced physicians. Although PMCT is necessarily lacking contrast enhancement, we reconstructed hypostatic sinuses into three-dimensional images resembling the results of in vivo venography. This simple methodology facilitates easy recognition of intracranial hypostasis.
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Brain structural changes in patients with chronic methylmercury poisoning in Minamata. Reviewed
Hirai T, Abe O, Nakamura M, Inui S, Uetani H, Ueda M, Azuma M
Brain research 1805 148278 2023.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Brain Research
Exploratory whole-brain studies in patients suffering from methylmercury (MeHg) poisoning have not been conducted. We aimed to evaluate the neuroanatomical differences between patients with chronic MeHg poisoning and healthy volunteers via magnetic resonance (MR) imaging. Patients included in this case-control study were divided into three categories based on whether MeHg exposure occurred in utero, under 15 years of age, or over 15 years of age, as fetal-, pediatric-, and adult-type patients, respectively. This study analyzed MR imaging data from 10 patients each of fetal, pediatric, and adult types of chronic MeHg poisoning in Minamata and corresponding 53, 37, and 15 age- and sex-matched healthy volunteers. Whole-brain voxel-based morphometry (VBM) analysis was used to determine the volumetric gray and white matter (GM and WM) differences in patients with chronic MeHg poisoning. Compared to healthy individuals, VBM revealed a significant reduction in GM in the cerebellar and calcarine areas in pediatric- and adult-type cases and in the thalamus of fetal-type cases. A significant reduction in WM volume was also noted in the cerebral and the cerebellar regions, especially in pediatric-type cases. Patients with chronic MeHg poisoning develop structural differences in the GM of the calcarine, the cerebellum, and the thalamus and in the WM of the cerebrum and cerebellum. These changes can appear, depending on the timing of MeHg exposure.
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Uetani H, Azuma M, Khant ZA, Watanabe Y, Kudo K, Kadota Y, Yokogami K, Takeshima H, Kuroda JI, Shinojima N, Hamasaki T, Mukasa A, Hirai T
Journal of computer assisted tomography 47 ( 4 ) 659 - 665 2023.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography
Purpose This study aimed to investigate the most useful clinical and magnetic resonance imaging (MRI) parameters for differentiating isocitrate dehydrogenase (IDH)-mutant and-wildtype glioblastomas in the 2016 World Health Organization Classification of Tumors of the Central Nervous System. Methods This multicenter study included 327 patients with IDH-mutant or IDH-wildtype glioblastoma in the 2016 World Health Organization classification who preoperatively underwent MRI. Isocitrate dehydrogenase mutation status was determined by immunohistochemistry, high-resolution melting analysis, and/or IDH1/2 sequencing. Three radiologists independently reviewed the tumor location, tumor contrast enhancement, noncontrast-enhancing tumor (nCET), and peritumoral edema. Two radiologists independently measured the maximum tumor size and mean and minimum apparent diffusion coefficients of the tumor. Univariate and multivariate logistic regression analyses with an odds ratio (OR) were performed. Results The tumors were IDH-wildtype glioblastoma in 306 cases and IDH-mutant glioblastoma in 21. Interobserver agreement for both qualitative and quantitative evaluations was moderate to excellent. The univariate analyses revealed a significant difference in age, seizure, tumor contrast enhancement, and nCET (P < 0.05). The multivariate analysis revealed significant difference in age for all 3 readers (reader 1, odds ratio [OR] = 0.960, P = 0.012; reader 2, OR = 0.966, P = 0.048; reader 3, OR = 0.964, P = 0.026) and nCET for 2 readers (reader 1, OR = 3.082, P = 0.080; reader 2, OR = 4.500, P = 0.003; reader 3, OR = 3.078, P = 0.022). Conclusions Age and nCET are the most useful parameters among the clinical and MRI parameters for differentiating IDH-mutant and IDH-wildtype glioblastomas.
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Watanabe T, Uehara H, Takeishi G, Chuman H, Azuma M, Yokogami K, Takeshima H
World neurosurgery 170 e817 - e826 2023.2
Language：English Publishing type：Research paper (scientific journal) Publisher：World Neurosurgery
Objective: Craniopharyngiomas remain surgically challenging because of the strong adhesion to vital neurovascular structures. We propose a system for the selection of surgical approaches based on the optic recess (OR) displacement pattern to facilitate surgical planning and obtain optimum visual and endocrinologic outcomes. Methods: Craniopharyngiomas were divided into 3 types based on the OR displacement pattern: superior, anterior, and involvement types. Selected surgical approaches and patient outcome were retrospectively reviewed according to these classifications. Visual and endocrinologic outcomes were compared among the groups. Results: This study included 26 patients with primary craniopharyngiomas who underwent surgery at our institution, classified into 11 anterior, 11 superior, and 4 involvement types. The extended endoscopic endonasal approach provided excellent exposure inferodorsal aspect of the chiasm for manipulation of the dissection plane in the anterior and superior types with midline location. A unilateral subfrontal approach was required for tumor of the superior type with lateral extension. An interhemispheric translamina terminalis approach could provide safe dissection under direct vision of strong adhesion at the superior aspect of the chiasm in the involvement type. Visual and endocrinologic outcomes were better in the involvement type compared with the superior and anterior types. Visual outcome was significantly correlated with preoperative visual function. Conclusions: Craniopharyngiomas with the involvement type are indicated for the translamina terminalis approach to achieve the best visual and endocrinologic outcome. Our classification of the OR displacement pattern is useful to select the optimal surgical approach for craniopharyngiomas more accurately and concisely, especially in cases with third ventricular extension.
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Nakagawa M., Nakaura T., Yoshida N., Azuma M., Uetani H., Nagayama Y., Kidoh M., Miyamoto T., Yamashita Y., Hirai T.
Academic Radiology 30 ( 1 ) 83 - 92 2023.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Academic Radiology
Rationale and Objectives: To evaluate the performance of a machine learning method to differentiate malignant from benign soft tissue tumors based on textural features on multiparametric magnetic resonance imaging (mpMRI). Materials and Methods: We enrolled 163 patients with soft tissue tumors whose diagnosis was pathologically proven (71 malignant, 92 benign). All patients underwent mpMRI. Twelve histographic and textural parameters were assessed on T1-weighted imaging (T1WI), T2-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient maps, and contrast-enhanced T1WI imaging. We compared mean signals of all sequences from the malignant and benign tumors using Welch's t-test. Prediction models were developed via a machine learning technique (support vector machine) using textural features of each sequence, clinical information (sex + age + tumor size), and the combined model incorporating all features. Areas under the receiver operating characteristic curves (AUCs) of these models were calculated using fivefold cross validation. Results: The diagnostic ability of clinical information model (AUC 0.85) was not inferior to the model with textural features of each sequence (AUC 0.79–0.84). The combined model showed the highest diagnostic ability (AUC 0.89). The AUC of the combined model (0.89) was comparable to those of two board-certified radiologists (0.89 and 0.87). Conclusions: Machine learning methods based on textural features on mpMRI and clinical information offer adequate diagnostic performance to differentiate between malignant and benign soft tissue tumors.
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Yamada A., Kinoshita M., Kamimura S., Jinnouchi T., Azuma M., Yamashita S., Yokogami K., Takeshima H., Moritake H.
Pediatric Hematology and Oncology 40 ( 7 ) 629 - 642 2023
Language：English Publishing type：Research paper (scientific journal) Publisher：Pediatric Hematology and Oncology
Atypical teratoid/rhabdoid tumor (AT/RT) is a rare aggressive central nervous system tumor that typically affects children under three years old and has poor survival with a high risk for neurologic deficits. The primary purpose of this study was to successfully treat the disease and delay or avoid whole-brain radiotherapy for children with AT/RT. A retrospective analysis was performed for six children diagnosed with AT/RT and treated with multimodal treatment at a single institute between 2014 and 2020. Furthermore, germline SMARCB1 aberrations and MGMT methylation status of the tumors were analyzed. One patient who did not receive a modified IRS-III regimen replaced with ifosphamide, carboplatin, and etoposide (ICE) in induction chemotherapy was excluded from this analysis. Five patients who received ICE therapy were under three years old. After a surgical approach, they received intensive chemotherapy and high-dose chemotherapy with autologous peripheral blood stem cell transplantation (HDCT/autoPBSCT) followed by intrathecal topotecan maintenance therapy. Three patients underwent single HDCT/autoPBSCT, and the other two received sequential treatment. Two patients with germline SMARCB1 aberrations and metastases died of progressive AT/RT or therapy-related malignancy, while 3 with localized tumors without germline SMARCB1 aberrations remained alive. One survivor received local radiotherapy only, while the other two did not undergo radiotherapy. All three surviving patients were able to avoid whole-brain radiotherapy. Our results suggest that AT/RT patients with localized tumors without germline SMARCB1 aberrations can be rescued with multimodal therapy, including induction therapy containing ICE followed by HDCT/autoPBSCT and intrathecal topotecan maintenance therapy without radiotherapy. Further large-scale studies are necessary to confirm this hypothesis.
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Kai K., Hamada T., Sakae T., Sato Y., Hiyoshi M., Inomata M., Suzuki Y., Nakamura S., Azuma M., Nanashima A.
Clinical Journal of Gastroenterology 2023
Language：English Publishing type：Research paper (scientific journal) Publisher：Clinical Journal of Gastroenterology
A 48-year-old woman underwent transcatheter arterial embolization (TAE) for a splenic artery aneurysm, which resulted in a partial splenic infarction in the middle lobe. Five years after TAE, a 20-mm diameter mass in the noninfarcted area of the spleen was detected on imaging, which grew to 25 mm in diameter after 6 months. MRI after gadolinium administration showed a 35 × 34 mm mass within the superior pole and 15 × 12 mm mass within the inferior pole. The patient underwent laparoscopic splenectomy and had an uneventful postoperative recovery. No evidence of recurrence was observed during the 2-year follow-up period after surgery. The mass was pathologically confirmed to be sclerosing angiomatoid nodular transformation (SANT) of the spleen. While some studies hypothesize that SANT is a response to vascular injury or trauma, to the best of our knowledge, there have been no previous reports of SANT occurring after procedures directly affecting splenic blood flow. Additionally, multifocal SANTs are reported to be very rare, accounting for only 4.7% of all reported SANTs of the spleen. We highlight a rare course of SANT of the spleen and discuss the possible relationship between blood flow abnormalities and the appearance of SANT.
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Lymphomas of Central Nervous System Reviewed
Yokogami K., Azuma M., Takeshima H., Hirai T.
Advances in experimental medicine and biology 1405 527 - 543 2023
Language：English Publishing type：Research paper (scientific journal) Publisher：Advances in experimental medicine and biology
Central nervous system (CNS) lymphoma consists of primary central nervous system lymphoma (PCNSL) and secondary CNS involvement by systemic lymphoma. This chapter focuses on the former. PCNSL is a relative rare disease, accounting for approximately 2.4-4.9% of all primary CNS tumors. It is an extra-nodal variant of non-Hodgkin's lymphoma (NHL), confined to the brain, leptomeninges, spinal cord, and eyes, with no systemic involvement. Recently, elderly patients (≥ 60 years) are increasing. Histologically, B cell blasts, which originate from late germinal center exit B cell, are growing and homing in CNS. Immunohistochemically, these cells are positive for PAX5, CD19, CD20, CD22, and CD79a. PCNSL shows relatively characteristic appearances on CT, MR imaging, and PET. Treatment first line of PCNSL is HD-MTX-based chemotherapy with or without rituximab and irradiation. Severe side-effect of this treatment is delayed onset neurotoxicity, which cause of cognitive impairment. Therefore, combined chemotherapy alone or chemotherapy with reduced-dose irradiation is more recommended for elderly patients. There is no established standard care for relapse of the PCNSLs. Temsirolimus, lenalidomide, temozolomide, and Bruton's tyrosine kinase (BTK) inhibitor ibrutinib are candidates for refractory patients. The prognosis of PCNSL has significantly improved over the last decades (median OS: 26 months, 5-year survival: 31%). Younger than 60 age and WHO performance status less than < or = 1 are associated with a significantly better overall survival.
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特集 ビギナーのための頭部画像診断 -Q＆Aアプローチ- 2023 所見別 小脳橋角部腫瘤はどのように考えればよいですか? Reviewed
東 美菜子
画像診断 43 ( 1 ) 72 - 73 2022.12
Language：English Publishing type：Research paper (scientific journal) Publisher：学研メディカル秀潤社
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Novel Mathematical Diagnostic Analysis of Malignant Biliary Stenosis Using Magnetic Resonance Cholangiography in Patients Undergoing Pancreaticoduodenectomy. Reviewed
Nanashima A, Komi M, Imamura N, Hiyoshi M, Hamada T, Tsuchimochi Y, Ichiki N, Enzaki M, Azuma M
Cancer diagnosis & prognosis 2 ( 6 ) 668 - 680 2022.11
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Yoshida N, Nakaura T, Morita K, Yoneyama M, Tanoue S, Yokota Y, Uetani H, Nagayama Y, Kidoh M, Azuma M, Hirai T
European journal of radiology 155 110489 2022.10
Language：English Publishing type：Research paper (scientific journal) Publisher：European Journal of Radiology
Purpose: To evaluate diffusion-weighted imaging (DWI) using echo planar imaging (EPI) with compressed SENSE (EPICS) of the head and neck magnetic resonance imaging (MRI). Method: We retrospectively observed 32 patients who underwent head and neck DWI according to either the conventional method (SENSE, reduction factor = 2), fast scanning method (SENSE, reduction factor = 4), or fast scanning method with EPICS (EPICS, reduction factor = 4). For quantitative analysis, contrast-to-noise-ratio (CNR), apparent diffusion coefficient (ADC) values, geometric distortion, and coefficient of variations (CV) were measured and compared. For qualitative analysis, all images were independently and blindly evaluated by two board-certified radiologists. Results: EPICS revealed the higher CNR between all location compared to those of SENSE with reduction factor = 4. Distortion in the anterior-posterior direction was significantly lower on EPICS than on the conventional scan (p = 0.02). A comparison between the ADC values of the EPICS and conventional scan revealed no significant differences. The CV was significantly lower for EPICS than the conventional scan [DWI: 0.22 (IQR: 0.15–0.30) vs 0.32 (IQR: 0.24–0.40), p = 0.02]. Conclusions: Compressed SENSE combined with the high acceleration factor can improve image quality, homogeneity, and distortion in the head and neck DWI maintaining ADC values and the scan time duration.
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Uetani H., Nakaura T., Kitajima M., Morita K., Haraoka K., Shinojima N., Tateishi M., Inoue T., Sasao A., Mukasa A., Azuma M., Ikeda O., Yamashita Y., Hirai T.
European Radiology 32 ( 7 ) 4527 - 4536 2022.7
Language：English Publishing type：Research paper (scientific journal) Publisher：European Radiology
Objectives: This study aimed to evaluate the efficacy of a combined wavelet and deep-learning reconstruction (DLR) method for under-sampled pituitary MRI. Methods: This retrospective study included 28 consecutive patients who underwent under-sampled pituitary T2-weighted images (T2WI). Images were reconstructed using either the conventional wavelet denoising method (wavelet method) or the wavelet and DLR methods combined (hybrid DLR method) at five denoising levels. The signal-to-noise ratio (SNR) of the CSF, hypothalamic, and pituitary images and the contrast between structures were compared between the two image types. Noise quality, contrast, sharpness, artifacts, and overall image quality were evaluated by two board-certified radiologists. The quantitative and the qualitative analyses were performed with robust two-way repeated analyses of variance. Results: Using the hybrid DLR method, the SNR of the CSF progressively increased as denoising levels increased. By contrast, with the wavelet method, the SNR of the CSF, hypothalamus, and pituitary did not increase at higher denoising levels. There was a significant main effect of denoising methods (p < 0.001) and denoising levels (p < 0.001), and an interaction between denoising methods and denoising levels (p < 0.001). For all five qualitative scores, there was a significant main effect of denoising methods (p < 0.001) and an interaction between denoising methods and denoising levels (p < 0.001). Conclusions: The hybrid DLR method can provide higher image quality for T2WI of the pituitary with compressed sensing (CS) than the wavelet method alone, especially at higher denoising levels. Key Points: •The signal-to-noise ratios of cerebrospinal fluid progressively increased with the hybrid DLR method, with an increase in the denoising level for cerebrospinal fluid in pituitary T2WI with CS. •The signal-to-noise ratios of cerebrospinal fluid using the conventional wavelet method did not increase at higher denoising levels. •All qualitative scores of hybrid deep-learning reconstructions at all denoising levels were higher than those for the wavelet denoising method.
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Effects of tube voltage and iodine contrast medium on radiation dose of whole-body CT Reviewed
Yoshida M., Nakaura T., Oda S., Kidoh M., Nagayama Y., Uetani H., Azuma M., Sakabe D., Hirai T., Funama Y.
Acta Radiologica 63 ( 4 ) 458 - 466 2022.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Radiologica
Background: The low-tube-voltage scan generally needs a higher tube current than the conventional 120 kVp to maintain the image noise. In addition, the low-tube-voltage scan increases the photoelectric effect, which increases the radiation absorption in organs. Purpose: To compare the organ radiation dose caused by iodine contrast medium between low tube voltage with low contrast medium and that of conventional 120-kVp protocol with standard contrast medium. Material and Methods: After the propensity-matching analysis, 66 patients were enrolled including 33 patients with 120 kVp and 600 mgI/kg and 33 patients with 80 kVp and 300 mgI/kg (50% iodine reduction). The pre- and post-contrast phases were assessed in all patients. The Monte Carlo simulation tool was used to simulate the radiation dose. The computed tomography (CT) numbers for 10 organs and the organ doses were measured. The organ doses were normalized by the volume CT dose index, and the 120-kVp protocol was compared with the 80-kVp protocol. Results: On contrast-enhanced CT, there were no significant differences in the mean CT numbers of the organs between 80-kVp and 120-kVp protocols except for the pancreas, kidneys, and small intestine. The normalized organ doses at 80 kVp were significantly lower than those of 120 kVp in all organs (e.g. liver, 1.6 vs. 1.9; pancreas, 1.5 vs. 1.8; spleen, 1.7 vs. 2.0) on contrast-enhanced CT. Conclusion: The low tube voltage with low-contrast-medium protocol significantly reduces organ doses at the same volume CT dose index setting compared with conventional 120-kVp protocol with standard contrast medium on contrast-enhanced CT.
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Azuma M., Nakada H., Takei M., Nakamura K., Katsuragawa S., Shinkawa N., Terada T., Masuda R., Hattori Y., Ide T., Kimura A., Shimomura M., Kawano M., Matsumura K., Meiri T., Ochiai H., Hirai T.
Emergency Radiology 29 ( 2 ) 317 - 328 2022.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Emergency Radiology
Purpose: The evaluation of all ribs on thin-slice CT images is time consuming and it can be difficult to accurately assess the location and type of rib fracture in an emergency. The aim of our study was to develop and validate a convolutional neural network (CNN) algorithm for the detection of acute rib fractures on thoracic CT images and to investigate the effect of the CNN algorithm on radiologists’ performance. Methods: The dataset for development of a CNN consisted of 539 thoracic CT scans with 4906 acute rib fractures. A three-dimensional faster region-based CNN was trained and evaluated by using tenfold cross-validation. For an observer performance study to investigate the effect of CNN outputs on radiologists’ performance, 30 thoracic CT scans (28 scans with 90 acute rib fractures and 2 without rib fractures) which were not included in the development dataset were used. Observer performance study involved eight radiologists who evaluated CT images first without and second with CNN outputs. The diagnostic performance was assessed by using figure of merit (FOM) values obtained from the jackknife free-response receiver operating characteristic (JAFROC) analysis. Results: When radiologists used the CNN output for detection of rib fractures, the mean FOM value significantly increased for all readers (0.759 to 0.819, P = 0.0004) and for displaced (0.925 to 0.995, P = 0.0028) and non-displaced fractures (0.678 to 0.732, P = 0.0116). At all rib levels except for the 1st and 12th ribs, the radiologists’ true-positive fraction of the detection became significantly increased by using the CNN outputs. Conclusion: The CNN specialized for the detection of acute rib fractures on CT images can improve the radiologists’ diagnostic performance regardless of the type of fractures and reader’s experience. Further studies are needed to clarify the usefulness of the CNN for the detection of acute rib fractures on CT images in actual clinical practice.
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Yamashita S, Takeshima H, Kadota Y, Azuma M, Fukushima T, Ogasawara N, Kawano T, Tamura M, Muta J, Saito K, Takeishi G, Mizuguchi A, Watanabe T, Ohta H, Yokogami K
Brain tumor pathology 39 ( 2 ) 88 - 98 2022.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Brain Tumor Pathology
After the new molecular-based classification was reported to be useful for predicting prognosis, the T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign has gained interest as one of the promising methods for detecting lower grade gliomas (LGGs) with isocitrate dehydrogenase (IDH) mutations and chromosome 1p/19q non-codeletion (IDH mut-Noncodel) with high specificity. Although all institutions could use T2-FLAIR mismatch sign without any obstacles, this sign was not completely helpful because of its low sensitivity. In this study, we attempted to uncover the mechanism of T2-FLAIR mismatch sign for clarifying the cause of this sign’s low sensitivity. Among 99 patients with LGGs, 22 were T2-FLAIR mismatch sign-positive (22%), and this sign as a marker of IDH mut-Noncodel showed a sensitivity of 55.6% and specificity of 96.8%. Via pathological analyses, we could provide evidence that not only microcystic changes but the enlarged intercellular space was associated with T2-FLAIR mismatch sign (p = 0.017). As per the molecular analyses, overexpression of mTOR-related genes (m-TOR, RICTOR) were detected as the molecular events correlated with T2-FLAIR mismatch sign (p = 0.020, 0.030. respectively). Taken together, we suggested that T2-FLAIR mismatch sign could pick up the IDH mut-Noncodel LGGs with enlarged intercellular space or that with overexpression of mTOR-related genes.
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Minako Azuma, Hiroshi Nakada, Zaw Aung Khant, Aya Kimura, Toshinori Hirai
J Comput Assist Tomogr 46 ( 1 ) 71 - 77 2022.1
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography
Objective We aimed to compare the accuracy of virtual noncontrast (VNC) images obtained from contrast-enhanced dual-layer spectral computed tomography (DLSCT) scans of the abdomen between pediatric and adult patients. Methods We retrospectively studied 10 pediatric and 40 adult patients who underwent unenhanced and contrast-enhanced DLSCT for nontraumatic acute abdomen or a follow-up of tumor or aneurysm. On true noncontrast (TNC) and VNC images, we placed a region-of-interest on 7 abdominal structures. The mean attenuation difference between VNC and TNC images was compared between these structures and between pediatric and adult scans. Data were analyzed by using the Wilcoxon signed-rank test, 1-way analysis of variance, Scheffe's test and independent t test. A P value less than 0.05 was considered statistically significant. Results In mean attenuation difference between VNC and TNC images, there was a significant interstructure difference in adult scans (P < 0.05), but not in pediatric scans. Mean attenuation difference between VNC and TNC images of the kidney was significantly higher on adult than pediatric scans (P = 0.0046). Conclusions The VNC images obtained from contrast-enhanced DLSCT data may be more accurate on pediatric than adult scans. Patient age can be a factor influencing the accuracy of the VNC images.
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Hattori Y., Azuma M., Nakada H., Kimura A., Khant Z.A., Tono T., Hirai T.
Journal of Computer Assisted Tomography 45 ( 4 ) 625 - 628 2021.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Computer Assisted Tomography
Objective We aimed to determine whether dual-energy computed tomography (CT) is useful for evaluating deep neck abscesses. Methods This study included 22 consecutive patients who were clinically suspected of having a deep neck abscess and underwent dual-energy CT. Conventional 120-kVp images, 70- and 40-keV virtual monochromatic images (VMIs), and iodine maps were inspected to calculate the contrast ratio of the abscess rim (AR) to the abscess center (AC) or to the adjacent muscle (M). The diagnostic certainty of abscesses was assessed on these images. Results Twenty (91%) of 22 patients had a definitive diagnosis. The contrast ratio for AR/AC and AR/M was significantly higher on 40-keV VMIs and iodine maps than on 120-kVp images and 70-keV VMIs (P < 0.05). On both 40-keV VMIs and iodine maps, the diagnostic certainty of abscess improved in 3 (15%) cases compared with 120-kVp images and 70-keV VMIs. Conclusions Dual-energy CT-based 40-keV VMIs and iodine maps are useful for evaluating deep neck abscesses and may improve diagnostic certainty.
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Kawano M., Azuma M., Hattori Y., Ikushima I., Kai K., Higuchi K., Kawano T., Matsumoto F., Uchinokura S., Irisa G., Ohta H., Hirai T.
Emergency Radiology 28 ( 3 ) 675 - 678 2021.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Emergency Radiology
We report the short-term results with aspiration embolectomy using an ACE68 reperfusion catheter to treat patients with acute embolic superior mesenteric artery (SMA) occlusion. Our study included 4 consecutive male patients ranging in age from 72 to 86 years (mean age 79 years). In all patients, the main trunk of the SMA was occluded. The technical success rate was 100% for all procedures. There were no major procedure-related complications. One patient underwent laparotomy with intestinal resection after successful recanalization. No patient reported clinical symptoms of abdominal ischemia at follow-up. Our short-term experience shows that percutaneous aspiration embolectomy using an ACE68 reperfusion catheter is an effective treatment for acute mesenteric ischemia.
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Azuma M., Kadota Y., Matsuyama M., Moritake H., Hirai T.
Japanese Journal of Radiology 39 ( 6 ) 564 - 570 2021.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Radiology
Objective: We evaluated the usefulness of fat-suppressed three-dimensional T1-weighted volume isotropic turbo spin-echo acquisition (FS 3D T1W-VISTA) imaging for the evaluation of the ectopic posterior pituitary gland (EPPG). Materials and methods: This retrospective study included 9 patients with EPPG due to causes other than tumor. All underwent sagittal two-dimensional (2D) T1W-, FS 3D T1W-VISTA- (VISTA), and 3D T2W-driven equilibrium radiofrequency reset pulse (DRIVE) imaging. Two radiologists independently reviewed the 2D T1W- and VISTA images for their image quality and for visualization of the EPPG and of pituitary stalk transection. DRIVE findings were used as the reference standard for pituitary stalk transection. Interobserver and intermodality agreements were evaluated with the kappa (κ) coefficient. The mean grade assigned to the 2D T1W- and the VISTA imaging technique for visualization of the EPPG was assessed by the Mann–Whitney U test. Results: Interobserver agreement for visualization of the EPPG on 2D T1W- and VISTA images was excellent (κ = 0.82 and κ = 1.00, respectively). The mean grade for EPPG visualization was significantly higher for VISTA- than 2D T1W images (p = 0.0039). Conclusion: FS 3D T1W-VISTA imaging is useful for the evaluation of EPPG. A secondary abstract: Conventional MRI yields insufficient information for the evaluation of the ectopic posterior pituitary gland (EPPG). The visualization of the EPPG was significantly higher for fat-suppressed three-dimensional T1-weighted volume isotropic turbo spin-echo acquisition (FS 3D T1W-VISTA) than 2D T1W images. FS 3D T1W-VISTA imaging is useful for the evaluation of the EPPG.
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Azuma M., Khant Z.A., Yoneyama M., Ikushima I., Hamanaka H., Yokogami K., Chosa E., Takeshima H., Hirai T.
Japanese Journal of Radiology 39 ( 5 ) 487 - 493 2021.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Radiology
Purpose: We aimed to evaluate the feasibility of 3D broadband inversion-recovery-prepared ultrashort echo-time (3D IRP UTE) imaging for assessing ossification of the posterior longitudinal ligament (OPLL). Materials and methods: The study consisted of 25 consecutive patients with cervical OPLL [13 women, 12 men; mean age 66.3 (47–84) years] who underwent CT, 3T conventional MR, and 3D IRP UTE imaging studies. Two readers independently assessed the 3D IRP UTE images for the type (mixed, continuous, circumscribed, segmental) and distribution of OPLL. All readers consensually assessed the diagnostic certainty of OPLL on conventional MR and 3D IRP UTE images by using a 3-point scale system. Interobserver and intermodality agreement was assessed by κ statistics. A Wilcoxon signed-rank test was used to evaluate the difference of diagnostic certainty between conventional MR and 3D IRP UTE imaging. Results: Interobserver and intermodality agreements were good (κ = 0.73) and excellent (κ = 0.81) for the OPLL type, and excellent (κ = 0.85) and good (κ = 0.76) for the assessment of the distribution of OPLL, respectively. The mean level of the diagnostic certainty of OPLL was significantly higher for 3D IRP UTE than conventional MR imaging (p = 0.002). Conclusion: 3D IRP UTE imaging may be useful for assessing OPLL.
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Conditional unnecessity of head CT for whole-body CT of traffic accident victims: a pilot study Reviewed
Azuma M., Nakada H., Kitatani K., Shinkawa N., Khant Z.A., Ochiai H., Hirai T.
Emergency Radiology 28 ( 2 ) 273 - 278 2021.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Emergency Radiology
Purpose: To investigate whether head CT should be included in whole-body CT in road traffic accident victims. Methods: A review of electronic medical records identified 124 patients (81 males, 43 females; age 4 to 92 years, mean 47.7 years) involved in a road traffic accident in a 12-month period. All had undergone whole-body CT and physical and neurologic examinations. We recorded their age, sex, Glasgow Coma Scale (GCS), systolic blood pressure (SBP), the type of traffic accident, and the presence/absence of visible trauma above the clavicles (VTCs) and of acute traumatic brain injury (TBI) on CT. Statistical analyses were performed to evaluate predictors of acute TBI. Results: Of 124 patients, 34 (27%) manifested acute TBI on CT. Univariate analysis identified their age, GCS, SBP, VTCs, and the accident type as statistically significant factors for acute TBI (p < 0.05). Multivariate analysis demonstrated VTCs, GCS score < 15, and SBP ≤ 90 mmHg were significant independent predictors of acute TBI (p = 0.001, p = 0.001, and p = 0.004, respectively); the odds ratio was 16.07 for VTCs, 14.85 for GCS score < 15, and 13.78 for SBP ≤ 90 mmHg. No patients without both decrease in GCS score and VTCs manifested acute TBI. Conclusion: Our pilot study showed that visible trauma above the clavicles and decrease in GCS score were highly associated with the presence of acute TBI in road traffic accident victims. In whole-body CT, a head CT may not be indicated in patients without these factors.
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Kidoh M., Oda S., Nakato K., Sakabe D., Kanazawa H., Takashio S., Nakaura T., Nagayama Y., Sasao A., Hatemura M., Funama Y., Kaikita K., Tsujita K., Ikeda O., Azuma M., Hirai T.
European Journal of Radiology 136 109530 2021.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：European Journal of Radiology
Purpose: CT is considered the non-invasive gold standard for evaluating cardiac implantable electronic devices (CIEDs) lead perforation, but metal artifacts caused by the lead tip affect the image quality and make a definitive diagnosis challenging. We compared the performances of the metal artifact reduction (MAR) algorithm and the conventional algorithm for identification of the right ventricular (RV) lead tip position in cardiac CT studies of patients with CIEDs. Method: Forty-seven consecutive patients (26 men; age 70.3 ± 15.4 years) with CIEDs underwent cardiac CT. Using the conventional and MAR algorithm, two image reconstructions were performed for each scan. We calculated the artifact index (AI) to assess the quantitative capability of the MAR algorithm for artifact reduction and visually assessed the RV lead tip position on both images as follows: non-perforation, perforation, and equivocal. Results: The mean AIs were significantly lower with the MAR algorithm than with the conventional algorithm (96.7 ± 40.1 HU vs. 284.6 ± 134.1 HU, P < 0.001). Thirteen (27.7 %) patients were diagnosed as equivocal using the conventional algorithm but were diagnosed with perforation (2 patients) and non-perforation (11 patients) using the MAR algorithm (equivocal rate: 27.7 % vs. 0%, P < 0.001). Using the MAR algorithm, all cases were diagnosed with perforation (6 patients, 12.8 %) or non-perforation (41 patients, 87.2 %). Conclusions: The MAR algorithm effectively reduced metal artifacts and allowed us to diagnose the presence or absence of perforation in all cases, whereas definitive diagnosis was difficult with the use of conventional algorithm in 27.7 % of cases.
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A National Survey on Safety Management at MR Imaging Facilities in Japan Reviewed
Azuma Minako, Kumamaru Kanako K., Hirai Toshinori, Khant Zaw Aung, Koba Ritsuko, Ijichi Shinpei, Jinzaki Masahiro, Murayama Sadayuki, Aoki Shigeki
Magnetic Resonance in Medical Sciences 20 ( 4 ) 347 - 358 2021
Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine
Purpose: To investigate safety management at Japanese facilities performing human MRI studies.Methods: All Japanese facilities performing human MRI studies were invited to participate in a comprehensive survey that evaluated their MRI safety management. The survey used a questionnaire prepared with the cooperation of the Safety Committee of the Japanese Society for Magnetic Resonance in Medicine. The survey addressed items pertaining to the overall MRI safety management, questions on the occurrence of incidents, and questions specific to facility and MRI scanner or examination. The survey covered the period from October 2017 to September 2018. Automated machine learning was used to identify factors associated with major incidents.Results: Of 5914 facilities, 2015 (34%) responded to the questionnaire. There was a wide variation in the rate of compliance with MRI safety management items among the participating facilities. Among the facilities responding to this questionnaire, 5% reported major incidents and 27% reported minor incidents related to MRI studies. Most major incidents involved the administration of contrast agents. The most influential factor in major incidents was the total number of MRI studies performed at the facility; this number was significantly correlated with the risk of major incidents (<i>P</i> < 0.0001).Conclusion: There were large variations in the safety standards applied at Japanese facilities performing clinical MRI studies. The total number of MRI studies performed at a facility affected the number of major incidents.
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Azuma Minako, Khant Zaw Aung, Kadota Yoshihito, Takeishi Go, Watanabe Takashi, Yokogami Kiyotaka, Takeshima Hideo, Hirai Toshinori
Magnetic Resonance in Medical Sciences 20 ( 4 ) 404 - 409 2021
Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society for Magnetic Resonance in Medicine
Purpose: Half of the surgically proven Rathke’s cleft cysts (RCCs) can be preoperatively misdiagnosed as cystic pituitary adenoma (CPA). We aimed to evaluate the usefulness of contrast-enhanced (CE) 3D T2 fluid-attenuated inversion-recovery (3D T2-FLAIR) imaging for differentiating between CPA and RCC.Methods: This retrospective study included six patients with RCC (all pathologically confirmed) and six patients with CPA (five pathologically confirmed, one clinically diagnosed). The 12 patients underwent pre- and post-contrast T1-weighted (T1W)- and 3D T2-FLAIR imaging at 3T. Based on the degree of enhancement of the lesion wall, two radiologists independently scored the images using a 3-point grading system. Interobserver agreement was calculated by using the κ coefficient. The statistical significance of grading differences was analyzed with the Mann–Whitney U-test. Another neuroradiologist first interpreted conventional MR images (1st session), and then the reader read images to which the 3D T2-FLAIR images had been added (2nd session). Sensitivity, specificity, and accuracy of the reader’s interpretation were calculated.Results: Interobserver agreement for post-contrast T1W- and 3D T2-FLAIR images was excellent (κ = 1.000 and 0.885, respectively). Although the mean enhancement grade on post-contrast T1W images of RCCs and CPAs was not significantly different, on post-contrast 3D T2-FLAIR images it was significantly higher for RCCs and CPAs (<i>P</i> < 0.05). Three CPAs (50%) showed remarkable, donut-like enhancement along the inner margin of the cyst on CE-3D T2-FLAIR images; this was not the case on CE-T1W images. The sensitivity, specificity, and accuracy of the 2nd session were 1.00, 0.83, and 0.92, respectively, which were improved compared to the 1st session (1.00, 0.50, and 0.75, respectively).Conclusion: CE-3D FLAIR imaging is useful for discriminating CPAs and RCCs.
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特集 時系列から学ぶ中枢神経疾患の画像診断-MR Retroscopy- Ⅱ.天幕上(大脳)A. 脳実質内? 脳実質外? 2 前頭部正中の嗅索と連続する腫瘤 Reviewed
東 美菜子, 門田 善仁, 平井 俊範
画像診断 40 ( 10 ) 1048 - 1051 2020.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：学研メディカル秀潤社
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特集 時系列から学ぶ中枢神経疾患の画像診断-MR Retroscopy- Ⅱ.天幕上(大脳)D. 側頭葉･大脳半球 4 脳幹を含む一側大脳の広範な病変 Reviewed
東 美菜子
画像診断 40 ( 10 ) 1084 - 1087 2020.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：学研メディカル秀潤社
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Kadota Y., Hirai T., Azuma M., Hattori Y., Khant Z.A., Hori M., Saito K., Yokogami K., Takeshima H.
Journal of Neuroradiology 47 ( 3 ) 197 - 202 2020.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Neuroradiology
Background and purpose: Neurite orientation dispersion and density imaging (NODDI) is a new technique that applies a three-diffusion-compartment biophysical model. We assessed the usefulness of NODDI for the differentiation of glioblastoma from solitary brain metastasis. Methods: NODDI data were prospectively obtained on a 3T magnetic resonance imaging (MRI) scanner from patients with previously untreated, histopathologically confirmed glioblastoma (n = 9) or solitary brain metastasis (n = 6). Using the NODDI Matlab Toolbox, we generated maps of the intra-cellular, extra-cellular, and isotropic volume (VIC, VEC, VISO) fraction. Apparent diffusion coefficient – and fraction anisotropy maps were created from the diffusion data. On each map we manually drew a region of interest around the peritumoral signal-change (PSC) – and the enhancing solid area of the lesion. Differences between glioblastoma and metastatic lesions were assessed and the area under the receiver operating characteristic curve (AUC) was determined. Results: On VEC maps the mean value of the PSC area was significantly higher for glioblastoma than metastasis (P < 0.05); on VISO maps it tended to be higher for metastasis than glioblastoma. There was no significant difference on the other maps. Among the 5 parameters, the VEC fraction in the PSC area showed the highest diagnostic performance. The VEC threshold value of ≥ 0.48 yielded 100% sensitivity, 83.3% specificity, and an AUC of 0.87 for differentiating between the two tumor types. Conclusions: NODDI compartment maps of the PSC area may help to differentiate between glioblastoma and solitary brain metastasis.
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Characterization of Carotid Plaque Components by Quantitative Susceptibility Mapping Reviewed
M.Azuma, K.Maekawa, A.Yamashita, K.Yokogami, M.Enzaki, Z.A.Khant, H.Takeshima, Y.Asada, Y.Wang, T.Hirai
American Journal of Neuroradiology 41 ( 2 ) 310 - 317 2020.2
Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology
Background and Purpose: Intraplaque hemorrhage in the carotid artery is related to an increased risk of cerebrovascular ischemic events. We aimed to investigate whether quantitative susceptibility mapping can characterize carotid artery plaque components and quantify the severity of intraplaque hemorrhage. Materials and Methods: For this ex vivo quantitative susceptibility mapping study, 9 carotid endarterectomy specimens were imaged on a 3T MR imaging scanner using a 3D multi-echo gradient-echo sequence and a microscopy coil. The samples were examined histologically using immunostains, including glycophorin A and Prussian blue. The areas of erythrocytes, iron deposits, calcification, and fibrous matrices observed on stained sections were compared with quantitative susceptibility mapping findings and their mean susceptibility values. Results: Intraplaque hemorrhage and iron deposits were observed only in areas hyperintense on quantitative susceptibility mapping; calcifications and fibrous matrices were prevalent in hypointense areas. The mean susceptibility values for necrotic cores with intraplaque hemorrhage but no iron deposits, cores with iron deposits but no intraplaque hemorrhage, cores without either intraplaque hemorrhage or iron deposits, and cores with calcification were 188 ± 51, 129 ± 49, -11 ± 17, and -158 ± 78 parts per billion, respectively. There was a significant difference in the mean susceptibility values among the 4 histologic components (P<.01). The mean susceptibility values of the whole plaque positively correlated with the percentage area positive for glycophorin A (r40.65, P<.001) and Prussian blue (r40.47, P<.001). Conclusions: Our findings suggest that quantitative susceptibility mapping can characterize the composition of carotid plaques and quantify the degree of intraplaque hemorrhage and iron deposits.
DOI： 10.3174/ajnr.A6374
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M.Azuma, Z.A.Khant, M.Kitajima, H.Uetani, T.Watanabe, K.Yokogami, H.Takeshima, T. Hirai
American Journal of Neuroradiology 41 ( 1 ) 106 - 110 2020.1
Language：English Publishing type：Research paper (scientific journal) Publisher：American Journal of Neuroradiology
BACKGROUND AND PURPOSE: Because it can be difficult to discriminate between a Rathke cleft cyst and cystic craniopharyngioma by conventional MR imaging alone, we investigated whether contrast-enhanced 3D T2-FLAIR MR imaging at 3T helps to distinguish a Rathke cleft cyst from a cystic craniopharyngioma. MATERIALS AND METHODS: We evaluated pre- and postcontrast T1-weighted and 3D T2-FLAIR images of 17 patients with pathologically confirmed Rathke cleft cyst (n = 10) or cystic craniopharyngioma (n = 7). All underwent 3T MR imaging studies before surgery. Two neuroradiologists independently recorded the enhancement grade of the lesion wall as grade 2 (most of the wall enhanced), grade 1 (some of the wall enhanced), and grade 0 (none of the wall enhanced). One neuroradiologist performed a blinded reading study of conventional MR images with/without 3D T2-FLAIR images. Interobserver agreement was determined by calculating the k coefficient. Statistical analyses, including receiver operating characteristic curve analysis were performed. RESULTS: Interobserver agreement for postcontrast T1WI and 3D T2-FLAIR images was excellent (k = 0.824 and k = 0.867, respectively). Although the difference in the mean enhancement grade of Rathke cleft cysts and cystic craniopharyngiomas was not significant on postcontrast T1WIs, it was significant on postcontrast 3D T2-FLAIR images (P = .0011). The area under the receiver operating characteristic curve of the conventional MR alone and conventional MR with 3D T2-FLAIR readings was 0.879 and 1.0, respectively, though there was no significant difference in the area under the curve between the 2 readings. CONCLUSIONS: Contrast-enhanced 3D T2-FLAIR imaging at 3T helps to distinguish a Rathke cleft cyst from cystic craniopharyngioma.
DOI： 10.3174/ajnr.A6359
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Combining quantitative susceptibility mapping to the morphometric index in differentiating between progressive supranuclear palsy and Parkinson's disease. Reviewed
Minako Azuma, Toshinori Hirai, Takeshi Nakaura, Mika Kitajima, Satoshi Yamashita, Mamoru Hashimoto, Kazumichi Yamada, Hiroyuki Uetani, Yasuyuki Yamashita, Yi Wang
Journal of the Neurological Sciences 406 116443 2019.11
Language：English Publishing type：Research paper (scientific journal)
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Three-dimensional reversed fast imaging with steady-state precession diffusion-weighted imaging for the detection of middle ear cholesteatoma Reviewed
Z.A. Khant, M.Azuma, Y.Kadota, Y.Hattori, N.Nagai, S.Ide, T.Tono, T.Hirai
Clinical Radiology 74 ( 11 ) 898.e7 - 898.e13 2019.11
Language：English Publishing type：Research paper (scientific journal)
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Evaluation of pituitary structures and lesions with turbo spin-echo diffusion-weighted imaging. Reviewed
Zaw Aung Khant, Minako Azuma, Yoshihito Kadota, Youhei Hattori, Hideo Takeshima,Kiyotaka Yokogami, Takashi Watanabe, Masahiro Enzaki, Takeshi Nakaura, Toshinori Hirai
Journal of the Neurological Sciences 405 116390 2019.10
Language：English Publishing type：Research paper (scientific journal)
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Value of DW-MRI in the preoperative evaluation of congenital cholesteatoma. Reviewed
Shinsuke Ide, Akira Ganaha, Tetsuya Tono, Takashi Goto, Noriaki Nagai, Keiji Matsuda, Minako Azuma, Toshinori Hirai
International Journal of Pediatric Otorhinolaryngology 124 34 - 38 2019.9
Language：English Publishing type：Research paper (scientific journal)
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Characteristics of preoperative visual disturbance and visual outcome after endoscopic endonasal transsphenoidal surgery for nonfunctioning pituitary adenoma in elderly patients. Reviewed
Takashi Watanabe, Hisao Uehara, Go Takeishi, Hideki Chuman, Minako Azuma, Kiyotaka Yokogami, Toshinori Hirai, Hideo Takeshima
World Neurosurgery 126 e706 - e712 2019.5
Language：English Publishing type：Research paper (scientific journal)
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Risk factors for atrophic gastritis in the Japanese young and middle-aged: a study using double-contrast upper gastrointestinal barium X-ray radiography Reviewed
Kimihiko Endo, Hiroshi Nakada, Yoshihito Kadota, Youichi Mizutani, Norihiro Shinkawa, Koji Onoe, Naoki Yoshinaga, Minako Azuma, Toshinori Hirai
Japanese Journal of Radiology 36 ( 12 ) 706 - 711 2018.12
Language：English Publishing type：Research paper (scientific journal)
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Differentiation between glioblastoma and solitary brain metastasis using neurite orientation dispersion and density imaging. Reviewed
Yoshihito Kadota, Toshinori Hiraia, Minako Azuma, YoheiHattori, Zaw Aung Khan, Masaaki Hori, Kiyotaka Saito, Kiyotaka Yokogami, Hideo Takeshima.
Journal of neuroradiology 2018.11
Language：English Publishing type：Research paper (scientific journal)
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Differentiating between Alzheimer Disease Patients and Controls with Phase-difference-enhanced Imaging at 3T: A Feasibility Study. Reviewed
Machiko Tateishi, Mika Kitajima, Toshinori Hirai, Tetsuya Yoneda, Mamoru Hashimoto, Nan Kurehana, Hiroyuki Uetani, Ryuji Fukuhara, Minako Azuma, Yasuyuki Yamashita.
Magnetic Resonance in Medical Sciences 17 ( 4 ) 283 - 292 2018.10
Language：English Publishing type：Research paper (scientific journal)
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Additive Value of 3T 3D CISS Imaging to Conventional MRI for Assessing the Abnormal Vessels of Spinal Dural Arteriovenous Fistulae. Reviewed
Hiroyuki Uetani, Toshinori Hirai, Mika Kitajima, Minako Azuma, Shigetoshi Yano, Hideo Nakamura, Keishi Makino, Yutaka Kai, Yasunori Nagayama, Yoshihito Kadota, Yasuyuki Yamashita
Magnetic Resonance in Medical Sciences 17 ( 3 ) 218 - 222 2018.7
Language：English Publishing type：Research paper (scientific journal)
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Circumventricular organs of human brain visualized on post-contrast 3D fluid-attenuated inversion recovery imaging. Reviewed
Minako Azuma, Toshinori Hirai, Yoshihito Kadota, Zaw Aung Khant, Yohei Hattori, Mika Kitajima, Hiroyuki Uetani, Yasuyuki Yamashita
Neuroradiology 60 ( 6 ) 583 - 590 2018.6
Language：English Publishing type：Research paper (scientific journal)
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Benefit of 3T Diffusion-weighted Imaging in Comparison to Contrast-enhanced MR Imaging for the Evaluation of Disseminated Lesions in Primary Malignant Brain Tumors. Reviewed
Kadota Y, Hirai T, Nakamura H, Makino K, Yano S, Nishimura S, Tateishi M, Azuma M, Kitajima M, Yamashita Y.
Magnetic Resonance in Medical Sciences 16 ( 3 ) 217 - 222 2017.7
Language：English Publishing type：Research paper (scientific journal)
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Successful transarterial embolization with cellulose porous beads for occipital haemangioma in an infant with Kasabach-Merritt syndrome Reviewed
ZAW AUNG KHANT, TOSHINORI HIRAI, OSAMU IKEDA, EIJI FURUKOJI, YOSHIHITO KADOTA, MINAKO AZUMA, NORIHIRO SHINKAWA, KEIJI KITATANI, YOICHI MIZUTANI, KIMIHIKO ENDO, YASUYUKI YAMASHITA
British Journal of Radiology case reports 2017.5
Language：English Publishing type：Research paper (scientific journal)
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T1 Shortening in the Cerebral Cortex after Multiple Administrations of Gadolinium-based Contrast Agents. Reviewed
Zaw Aung Khant, Toshinori Hirai, Yoshihito Kadota, Rie Masuda, Takanori Yano, Minako Azuma, Yukiko Suzuki, Kuniyuki Tashiro
Magnetic Resonance in Medical Sciences 16 ( 1 ) 84 - 86 2017.1
Language：English Publishing type：Research paper (scientific journal)
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Additive value of 320-section low-dose dynamic volume CT in relation to 3-T MRI for the preoperative evaluation of brain tumors. Reviewed
Hayashida E, Hirai T, Nakamura H, Kidoh M, Azuma M, Iryo Y, Kitajima M, Oda S, Utsunomiya D, Nakaura T, Yamashita Y.
Jpn J Radiol 34 ( 10 ) 691 - 699 2016.10
Language：English Publishing type：Research paper (scientific journal)
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Evaluation of Intracranial Vasculatures in Healthy Subjects with Arterial-Spin-Labeling-Based 4D-MR Angiography at 3T. Reviewed
Iryo Y, Hirai T, Nakamura M, Tateishi M, Hayashida E, Azuma M, Nishimura S, Kitajima M, Yamashita Y.
Magn Reson Med Sci. 15 ( 3 ) 335 - 339 2016.7
Language：English Publishing type：Research paper (scientific journal)
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Lateral Asymmetry and Spatial Difference of Iron Deposition in the Substantia Nigra of Patients with Parkinson Disease Measured with Quantitative Susceptibility Mapping. Reviewed
Azuma M, Hirai T, Yamada K, Yamashita S, Ando Y, Tateishi M, Iryo Y, Yoneda T, Kitajima M, Wang Y, Yamashita Y.
AJNR Am J Neuroradiol 37 ( 5 ) 782 - 788 2016.5
Language：English Publishing type：Research paper (scientific journal)
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Evaluation of Intracranial Arteriovenous Malformations With Four-Dimensional Arterial-Spin Labeling-Based 3-T Magnetic Resonance Angiography. Reviewed
Iryo Y, Hirai T, Nakamura M, Kawano T, Kaku Y, Ohmori Y, Kai Y, Azuma M, Nishimura S, Shigematsu Y, Kitajima M, Yamashita Y.
J Comput Assist Tomogr 40 ( 2 ) 290 - 296 2016.4
Language：English Publishing type：Research paper (scientific journal)