Papers - AZUMA Minako
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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)