研究者詳細 - 陣崎　雅弘

論文 - 陣崎　雅弘

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Usefulness of fine-tuning for deep learning based multi-organ regions segmentation method from non-contrast CT volumes using small training dataset

Hayashi Y., Shen C., Roth H.R., Oda M., Misawa K., Jinzaki M., Hashimoto M., Kumamaru K.K., Aoki S., Mori K.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE （Progress in Biomedical Optics and Imaging - Proceedings of SPIE） 11314 2020年

ISSN 9781510633957

© 2020 SPIE. This paper presents segmentation of multiple organ regions from non-contrast CT volume based on deep learning. Also, we report usefulness of fine-tuning using a small number of training data for multi-organ regions segmentation. In medical image analysis system, it is vital to recognize patient specific anatomical structures in medical images such as CT volumes. We have studied on a multi-organ regions segmentation method from contrast-enhanced abdominal CT volume using 3D U-Net. Since non-contrast CT volumes are also usually used in the medical field, segmentation of multi-organ regions from non-contrast CT volume is also important for the medical image analysis system. In this study, we extract multi-organ regions from non-contrast CT volume using 3D U-Net and a small number of training data. We perform fine-tuning from a pre-trained model obtained from the previous studies. The pre-trained 3D U-Net model is trained by a large number of contrast enhanced CT volumes. Then, fine-tuning is performed using a small number of non-contrast CT volumes. The experimental results showed that the fine-tuned 3D U-Net model could extract multi-organ regions from non-contrast CT volume. The proposed training scheme using fine-tuning is useful for segmenting multi-organ regions using a small number of training data.

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Successful depiction of systemic collateral supply to pulmonary artery in CTEPH using time-resolved 4D CT angiography: a case report

Tamura M., Kawakami T., Yamada Y., Kataoka M., Nakatsuka S., Fukuda K., Jinzaki M.

Pulmonary Circulation （Pulmonary Circulation） 10 （ 2 ） 2020年

ISSN 20458932

© The Author(s) 2020. A 49-year-old man with CTEPH (pre-procedural mean pulmonary artery pressure: 36 mmHg) underwent balloon pulmonary angioplasty. Chronic total occlusion of the left inferior pulmonary artery trunk was observed. To evaluate the collateral vessels of the chronic total occlusion, 4D-CTA was performed. The examination was performed using a 256-row detector CT system using the test bolus tracking method. 4D-CTA showed the bronchial artery-to-left inferior pulmonary artery collateral supply, which was confirmed by a selective bronchial artery angiography. The patient’s symptoms improved with balloon pulmonary angioplasty of the other stenotic lesions. 4D-CTA can noninvasively evaluate the anatomy and hemodynamics of multiple systemic collaterals simultaneously. This technique can support interventions in systemic artery-to-pulmonary artery collaterals, such as embolization, and could be helpful in challenging balloon pulmonary angioplasty interventions for chronic total occlusion to identify vessel structures distal to the chronic total occlusion and collateral channels for a retrograde approach.

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Sinking skin flap syndrome visualized by upright computed tomography

Yoshida K., Toda M., Yamada Y., Yamada M., Yokoyama Y., Fujiwara H., Kosugi K., Fukumura M., Koike K., Takahashi S., Yoshida K., Jinzaki M.

Acta Neurochirurgica （Acta Neurochirurgica） 162 （ 8 ） 1825 - 1828 2020年

ISSN 00016268

© 2020, Springer-Verlag GmbH Austria, part of Springer Nature. Sinking skin flap syndrome is a craniectomy complication characterized by new neurological dysfunction that typically worsens in the upright position and improves after cranioplasty. We present a 33-year-old man who experienced hemiparesis in the upright position after craniectomy. Upright computed tomography (CT) before cranioplasty showed a remarkable shift of the brain compared to supine CT. After cranioplasty, both symptoms and brain shift on CT resolved. Upright CT enables detection and objective evaluation of paradoxical herniation and midline shift that is not obvious on supine imaging modalities. Clinicians need to be aware of positional brain shift in postcraniectomy patients.

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Quantitative analysis of intervertebral disc degeneration using Q-space imaging in a rat model

Nakashima D., Fujita N., Hata J., Komaki Y., Suzuki S., Nagura T., Fujiyoshi K., Watanabe K., Tsuji T., Okano H., Jinzaki M., Matsumoto M., Nakamura M.

Journal of Orthopaedic Research （Journal of Orthopaedic Research） 38 （ 10 ） 2220 - 2229 2020年

ISSN 07360266

© 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC The degree of intervertebral disc (IVD) degeneration is qualitatively evaluated on T2-weighted imaging (T2WI). However, it is difficult to assess subtle changes in IVD degeneration using T2WI. Q-space imaging (QSI) is a quantitative diffusion-weighted imaging modality used to detect subtle changes in microenvironments. This study aimed to evaluate whether QSI can detect the inhibitory effects of the antioxidant N-acetylcysteine (NAC) in IVD degeneration. We classified female Wistar rats into control, puncture, and NAC groups (n = 5 per group). In the puncture and NAC groups, IVDs were punctured using a needle. The antioxidant NAC, which suppresses the progression of IVD degeneration, was orally administered in the NAC group 1 week prior to puncture. The progression and inhibitory effect of NAC in IVD degeneration were assessed using magnetic resonance imaging (MRI): IVD height, T2 mapping, apparent diffusion coefficient (ADC), and QSI. MRI was performed using a 7-Tesla system with a conventional probe (20 IVDs in each group). QSI parameters that were assessed included Kurtosis, the probability at zero displacement (ZDP), and full width at half maximum (FWHM). IVD degeneration by puncture was confirmed by histology, IVD height, T2 mapping, ADC, and all QSI parameters (P <.001); however, the inhibitory effect of NAC was confirmed only by QSI parameters (Kurtosis and ZDP: both P <.001; FWHM: P <.01). Kurtosis had the largest effect size (Kurtosis: 1.13, ZDP: 1.06, and FWHM: 1.02) when puncture and NAC groups were compared. QSI has a higher sensitivity than conventional quantitative methods for detecting the progressive change and inhibitory effect of NAC in IVD degeneration.

Diagnosis, prevention, and treatment of cardiovascular diseases in people with type 2 diabetes and prediabetes: a consensus statement jointly from the Japanese Circulation Society and the Japan Diabetes Society

Araki E., Tanaka A., Inagaki N., Ito H., Ueki K., Murohara T., Imai K., Sata M., Sugiyama T., Ishii H., Yamane S., Kadowaki T., Komuro I., Node K., Amano T., Anzai T., Babazono T., Emoto M., Fukuda K., Hagiwara N., Hirata K.i., Ikari Y., Ikeda T., Izumi C., Jinzaki M., Kaneto H., Katagiri H., Kimura T., Kobayashi Y., Maemura K., Matoba S., Minamino T., Mitani Y., Miura S.i., Morino Y., Nakamura J., Nishio Y., Ogawa W., Ohishi M., Okura H., Ono M., Sakata Y., Sato A., Shimada A., Shimizu W., Shimomura I., Shiojima I., Takamura M., Takeishi Y., Tanemoto K., Tanizawa Y., Terauchi Y., Tobe K., Tetsuou Y., Watada H., Yamauchi T., Yano M., Yoshioka N.

Diabetology International （Diabetology International） 2020年

ISSN 21901678

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Relationship between hip joint proximity area and sagittal balance parameters: an upright computed tomography study

Kikuchi S., Nakashima D., Yamada Y., Yamada M., Yokoyama Y., Kanaji A., Nakamura M., Nagura T., Jinzaki M.

European Spine Journal （European Spine Journal） 2020年

ISSN 09406719

Purpose: A close relationship between sagittal spinal alignment and hip osteoarthritis (OA) has been documented. This study aimed to examine the relationship between hip joint proximity area and sagittal balance parameters in healthy subjects. Methods: This prospective study enrolled 47 healthy volunteers who underwent 320-detector row upright computed tomography. Acquired data were reconstructed in a virtual three-dimensional space. The proximity area was determined by < 1 mm of the Hausdorff distance between the acetabulum and the femoral head. Volunteers were divided into the anterior and posterior proximity groups depending on the position of the closest area. Sagittal balance parameters [sagittal vertical axis (SVA), T1 spinopelvic inclination (T1-SPi), T1-pelvic angle, pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, thoracic kyphosis), offset distance between the centre of the acoustic meati (CAM) and C7 plumb line (CAM-C7-offset), and offset distance between the CAM and hip axis (HA) (CAM-HA-offset)] were compared between the two groups using independent sample t test. Results: The anterior proximity group (n = 24) had higher SVA (p = 0.016) and T1-Spi (p = 0.015) than the posterior proximity group (n = 23). CAM-HA-offset was higher in the posterior than in the anterior proximity group (p < 0.000). There was no difference in other parameters (p > 0.05). Conclusion: The anterior proximity group had a positive anterior spinal balance; the posterior proximity group may have a more posterior gravity line than the hip joint centre. The anterior spinal balance may contribute to the anterior loading of the hip joint, with known relation with the initiation and onset of hip OA.

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Projected lung areas using dynamic X-ray (DXR)

Hino T., Hata A., Hida T., Yamada Y., Ueyama M., Araki T., Kamitani T., Nishino M., Kurosaki A., Jinzaki M., Ishigami K., Honda H., Hatabu H., Kudoh S.

European Journal of Radiology Open （European Journal of Radiology Open） 7 2020年

Background: Dynamic X-ray (DXR) provides images of multiple phases of breath with less radiation exposure than CT. The exact images at end-inspiratory or end-expiratory phases can be chosen accurately. Purpose: To investigate the correlation of the projected lung area (PLA) by dynamic chest X-ray with pulmonary functions. Material and Methods: One hundred sixty-two healthy volunteers who received medical check-ups for health screening were included in this study. All subjects underwent DXR in both posteroanterior (PA) and lateral views and pulmonary function tests on the same day. All the volunteers took several tidal breaths before one forced breath as instructed. The outlines of lungs were contoured manually on the workstation with reference to the motion of diaphragm and the graph of pixel values. The PLAs were calculated automatically, and correlations with pulmonary functions and demographic data were analyzed statistically. Results: The PLAs have correlation with physical characteristics, including height, weight and BMI, and pulmonary functions such as vital capacity (VC) and forced expiratory volume in one second (FEV ). VC and FEV revealed moderate correlation with the PLAs of PA view in forced inspiratory phase (VC: right, r = 0.65; left, r = 0.69. FEV1: right, r = 0.54; left, r = 0.59). Multivariate analysis showed that body mass index (BMI), sex and VC were considered independent correlation factors, respectively. Conclusion: PLA showed statistically significant correlation with pulmonary functions. Our results indicate DXR has a possibility to serve as an alternate method for pulmonary function tests in subjects requiring contact inhibition including patients with suspected or confirmed covid-19. 1 1

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MR imaging of mushroom-like skin adnexal tumors in the scalp: A report of two cases

Arai M., Nozaki T., Matsusako M., Zenke Y., Arai S., Matsui M., Suzuki K., Jinzaki M., Kurihara Y.

Magnetic Resonance in Medical Sciences （Magnetic Resonance in Medical Sciences） 19 （ 3 ） 282 - 285 2020年

ISSN 13473182

Few studies had been published regarding imaging findings of skin adnexal tumors. We experienced two giant cases of them with a characteristic mushroom-like growth pattern. MRI showed a circumscribed mushroom-like shaped mass extruding from the subcutaneous tissue with microcystic lesions. Although differentiation between benignancy and malignancy may be difficult by radiological examinations, MRI may be helpful to identify its origin and differentiate soft tissue tumors with skin adnexal tumors in having these imaging findings.

A Case of Head and Neck Lymphatic Malformation in which Sclerotherapy with Polidocanol was Useful for Hemostasis

Kikuchi Akira, Aramaki-Hattori Noriko, Inoue Masanori, Ozawa Hiroyuki, Nakamura Shintaro, Sakai Shigeki, Okabe Keisuke, Nakatsuka Seishi, Jinzaki Masahiro, Kishi Kazuo

International Journal of Surgical Wound Care （一般社団法人日本創傷外科学会） 1 （ 1 ） 38 - 41 2020年

Lymphatic malformations that occur in the head and neck are often difficult to treat. Sclerotherapy using polidocanol, which has little tissue damage, can be treated with minimal dysfunction and complications. In particular, it is considered an effective treatment for superficial lesions that bleed from the mucosal surface. In this study, we performed sclerotherapy using polidocanol for a 17-year-old woman with lymphatic malformations with blood containing lymphorrhea in the pharynx and larynx. A total of 3 sclerotherapy treatments were performed, and lesion reduction and bloody lymphorrhea control were observed. At 1 year after treatment, the course of treatment was good with no re-enlargement of the lesions.

腹部リンパ漏病変に対するIVR

井上政則, 鳥飼秀幸, 伊東伸剛, 田村全, 小川遼, 中塚誠之, 陣崎雅弘

日本インターベンショナルラジオロジー学会雑誌（一般社団法人日本インターベンショナルラジオロジー学会） 34 （ 3 ） 187 - 192 2020年

ISSN 1340-4520

One of the important functions of the lymphatic system is maintenance of fluid balance, and lymphatic leakage after surgery potentially becomes a critical condition.<BR>Interventional techniques could not treat lymphatic leakage effectively mostly due to the lack of clinical imaging. However, the recently developed intranodal lymphangiography provides new insight into lymphatic intervention. At first, thoracic duct embolization has become the method of choice for the treatment of patients with chylothorax. Abdominal lymphatic leakage as a complication of abdominal and pelvic surgery is an uncommon but difficult-to-treat condition when conservative measures have failed. Embolization and sclerotherapy are also very useful for refractory lymphatic leakage. These current advances will open up new treatments and diag-nostic opportunities for abdominal lymphatic leakage.

Prediction of extraprostatic extension by MRI tumor contact length: difference between anterior and posterior prostate cancer

Matsumoto K., Akita H., Narita K., Hashiguchi A., Takamatsu K., Takeda T., Kosaka T., Mizuno R., Kikuchi E., Oya M., Jinzaki M.

Prostate Cancer and Prostatic Diseases （Prostate Cancer and Prostatic Diseases） 22 （ 4 ） 539 - 545 2019年12月

ISSN 13657852

© 2019, Springer Nature America, Inc. Background: Tumor contact length (TCL) is defined as the extent of contact between prostate cancer and the prostatic capsule, and its predictive value for microscopic extraprostatic extension (EPE) has been reported. However, the impact of the zonal origin (anterior or posterior tumor) of the tumor on the diagnosis of EPE is controversial. Methods: We retrospectively analyzed the records of 233 consecutive patients who underwent preoperative MRI and radical prostatectomy. We designated their tumors as anterior or posterior, and evaluated the correlation between the TCL measured by MRI and microscopic EPE in the radical prostatectomy specimen. Then, we created the predicted probability curves for EPE versus TCL for anterior and posterior prostate cancer. Results: There were 109 patients (47%) with an anterior tumor and 124 patients (53%) with a posterior tumor. Postoperative pathological analysis confirmed pT3 in 18 patients (17%) with an anterior tumor and in 53 patients (43%) with a posterior tumor. Multivariate analysis demonstrated that the zonal origin of the tumor was an independent predictive factor for EPE. We developed separate probability curves of EPE versus TCL for anterior and posterior prostate cancer, which revealed that anterior tumors were less likely to invade the extraprostatic tissues. Among patients whose TCL was 10–20 mm, 9/32 patients (28%) with an anterior tumor had EPE compared with 24/45 patients (53%) with a posterior tumor (p = 0.036). The decision curve of this EPE predictive model had high clinical efficacy. Conclusions: Our results indicate that anterior tumors have more favorable pathological characteristics than posterior tumors with the same TCL measured by MRI. We constructed two separate predicted probability curves for EPE after discriminating anterior and posterior tumors, which will be useful for decision making in clinical practice.

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Use of CT in a standing position for preoperative evaluation in abdominal incisional hernia: A pilot study

Sakamoto Y., Yamada M., Yamada Y., Yokoyama Y., Kishi K., Jinzaki M.

Journal of plastic, reconstructive & aesthetic surgery : JPRAS （Journal of plastic, reconstructive & aesthetic surgery : JPRAS） 72 （ 12 ） 2019年12月

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Predictive markers for MGMT promoter methylation in glioblastomas

Kanazawa T., Minami Y., Jinzaki M., Toda M., Yoshida K., Sasaki H.

Neurosurgical Review （Neurosurgical Review） 42 （ 4 ） 867 - 876 2019年12月

ISSN 03445607

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. The promoter methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) gene has been described as the most important predictor of chemotherapeutic response and patients’ survival in glioblastomas (GBs). Therefore, prediction of the MGMT promoter methylation status by imaging would help to preoperatively decide the overall treatment strategy as well as surgical strategy. This study aimed to detect imaging parameters to predict MGMT promoter methylation in GBs by using a commercially available software. We investigated three imaging features (ring enhancement, tumor location, and laterality) and apparent diffusion coefficient (ADC) parameters in 48 newly diagnosed GBs treated at Keio University Hospital in 2006 or later. For ADC, texture analyses were performed. Regions of interest (ROIs) were drawn manually with reference to contrast-enhanced areas, excluding necrotic and cystic regions. Mean ADC value and ADC histogram parameters, including kurtosis, skewness, and entropy, were compared with MGMT promoter methylation. Each parameter was evaluated to determine correlation with MGMT promoter methylation, and the parameters with significant associations with the methylation status were correlated with the MGMT-positive cell ratio determined by immunohistochemistry (IHC) analysis. The mean ADC value and ADC entropy were significantly associated with MGMT promoter methylation. The combination of mean ADC value and ADC entropy predicted MGMT promoter methylation, with a PPV of 81.2% and specificity of 88.9%. The mean ADC value and ADC entropy were negatively correlated with the MGMT-positive cell ratio in the IHC analysis. This study demonstrated that texture analyses of ADC histograms in GBs were predictive of MGMT promoter methylation.

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Picked-up Knowledge from Foreign Journals 血管周囲の脂肪

中原健裕, 奥田茂男, 陣崎雅弘

画像診断（学研メディカル秀潤社） 40 （ 1 ） 112 - 114 2019年11月

ISSN 0285-0524

Three-dimensional kinematic change of hindfoot during full weightbearing in standing: An analysis using upright computed tomography and 3D-3D surface registration

Kaneda K., Harato K., Oki S., Ota T., Yamada Y., Yamada M., Matsumoto M., Nakamura M., Nagura T., Jinzaki M.

Journal of Orthopaedic Surgery and Research （Journal of Orthopaedic Surgery and Research） 14 （ 1 ） 2019年11月

© 2019 The Author(s). Background: Weightbearing of the hindfoot affects positional changes of the ankle joint and subtalar joint (ankle-joint complex [AJC]). However, it is difficult to assess the kinematic changes in the hindfoot in a natural full weightbearing condition using conventional CT or cone beam computed tomography (CT) due to limitations of acquiring foot images under a physiological weightbearing condition using those imaging modalities. Analysis of AJC kinematics using fluoroscopy and 2D-3D registration technique requires data on the number of steps and amount of time to build and match the bones. This study aimed to analyze the effect of full weightbearing on hindfoot motion when standing using upright CT and 3D-3D surface registration. Methods: Forty-eight AJCs of 24 asymptomatic volunteers (13 women, 11 men) were examined under no weightbearing, 50% weightbearing, and single leg full weightbearing conditions while standing. The CT images were acquired from the distal femur to the whole foot using a 320-row upright CT scanner. The condition of each weightbearing stance was measured using a pressure mat. Bone-to-bone rotations of the talus relative to the tibia and calcaneus relative to the talus were evaluated using the surface registration technique. Image quality of the CT and intra- and interobserver reliabilities of the rotation angle were also evaluated. Results: All CT images were excellent or good quality and the intra- and interobserver correlation coefficients for the angle were 0.996 and 0.995, respectively. The motion of the ankle joint and subtalar joint under 50% and 100% weightbearing were as follows (in degrees); the talus plantarflexed (5.1 ± 4.5 and 6.8 ± 4.8), inverted (1.3 ± 1.4 and 2.0 ± 1.6), and internally rotated (2.4 ± 4.2 and 4.3 ± 4.6) relative to the tibia, and the calcaneus dorsiflexed (2.8 ± 1.4 and 3.8 ± 1.7), everted (5.3 ± 2.6 and 8.0 ± 3.6), and externally rotated (3.0 ± 2.0 and 4.1 ± 2.4) relative to the talus, respectively. Conclusions: The effect of weightbearing was clearly identified using an upright CT and the 3D-3D registration technique. Three-dimensional kinematics under static full weightbearing were opposite between the ankle and subtalar joints on their respective axes.

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Myocardial T1 values in healthy volunteers measured with saturation method using adaptive recovery times for T1 mapping (SMART1Map) at 1.5 T and 3 T

Matsumoto S., Okuda S., Yamada Y., Suzuki T., Tanimoto A., Nozaki A., Jinzaki M.

Heart and Vessels （Heart and Vessels） 34 （ 11 ） 1889 - 1894 2019年11月

ISSN 09108327

© 2019, Springer Japan KK, part of Springer Nature. Myocardial T1 mapping is clinically valuable for assessing the myocardium, and modified look-locker inversion-recovery (MOLLI) approaches have been commonly used for measuring myocardial T1 values. To date, several other sequences have been developed for measuring myocardial T1 values, and saturation-recovery-based sequences have been shown to be less dependent on various factors, such as T2 times and magnetization transfer, than inversion-recovery techniques. Systematic differences in T1 values between different sequences have been reported; therefore, definition of the normal range of native T1 values is required before clinical usage can begin. The purpose of this study was to evaluate the reference range and sex dependency of native T1 values in the myocardium measured using one such saturation-recovery sequence, i.e., saturation method using adaptive recovery times for cardiac T1 mapping (SMART1Map). Myocardial T1 values were compared between SMART1Map and MOLLI in 24 young healthy volunteers at 1.5 T and 3 T, and differences in the T1 values between the sexes were assessed. The mean native T1 values in the myocardium were significantly longer with SMART1Map than MOLLI [1530.4 ± 49.2 vs 1222.1 ± 48.9 ms at 3 T (p < 0.001) and 1227.3 ± 41.9 ms vs 1014.8 ± 49.4 ms at 1.5 T (p < 0.001)]. A significant difference between the sexes was observed in the T1 values obtained using each sequence, excluding SMART1Map at 3 T. The SMART1Map has a potential advantage to overcome the shortcoming of MOLLI, which underestimates T1 values; however, the sex-dependent difference remains obscure using SMART1Map.

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Usefulness of contrast-enhanced ultrasonography for diagnosis of renal cell carcinoma in dialysis patients: Comparison with computed tomography

Hashimoto M., Ohkuma K., Akita H., Yamada Y., Nakatsuka S., Mizuno R., Oya M., Jinzaki M.

Medicine (United States) （Medicine (United States)） 98 （ 47 ） 2019年11月

ISSN 00257974

© 2019 the Author(s). Published by Wolters Kluwer Health, Inc. Aims:To investigate the usefulness of contrast-enhanced ultrasonography for diagnosing renal cell carcinoma (RCC) in dialysis patients.Material and methods:Of 1301 dialysis patients who underwent abdominal computed tomography (CT) between January 2012 and March 2017, 19 were suspected to have solid renal lesions; of these patients, 18 gave consent for and underwent contrast-enhanced ultrasonography with perflubutane in addition to CT; 13 underwent dynamic contrast-enhanced CT, and 5, who could not be administered iodinated contrast media, underwent unenhanced CT. The final diagnoses were based on histopathological findings or the presence/absence of enlargement of the lesion during follow-up.Results:Of the 19 lesions in 18 patients, 14 were diagnosed as RCC and 5 as benign cysts. CT facilitated accurate diagnosis in 10/19 lesions (52.6%) with obvious enhancement (≥20 Hounsfield units [HU]), while definitive diagnosis by CT was difficult in 9 lesions: 2 lesions showed ambiguous enhancement (10-20 HU), 1 lesion was an inflammatory cyst with obvious enhancement, and 6 lesions were assessed by unenhanced CT. Compared with CT, contrast-enhanced ultrasonography allowed more accurate diagnosis (McNemar test, P = .02) in 17/19 lesions (89.5%, 14 RCC and 3 cysts; including all lesions assessed by unenhanced CT and 2 with ambiguous enhancement on CT), with 1 false-positive (inflammatory cyst with hyper-enhancement) and 1 false-negative result due to deep location of the lesion.Conclusions:Contrast-enhanced ultrasonography was useful for the diagnosis of RCC in dialysis patients with suspected solid renal lesions especially when contrast enhancement was not obvious on CT or contrast-enhanced CT could not be performed.

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Four-dimensional ct analysis using sequential 3d-3d registration

Oki S., Kaneda K., Yamada Y., Yamada M., Morishige Y., Harato K., Matsumura N., Nagura T., Jinzaki M.

Journal of Visualized Experiments （Journal of Visualized Experiments） 2019 （ 153 ） 2019年11月

ISSN 1940087X

© 2019 Journal of Visualized Experiments. Four-dimensional computed tomography (4DCT) provides a series of volume data and visualizes joint motions. However, numerical analysis of 4DCT data remains difficult because segmentation in all volumetric frames is time-consuming. We aimed to analyze joint kinematics using a sequential 3D-3D registration technique to provide the kinematics of the moving bone with respect to the fixed bone semiautomatically using 4DCT DICOM data and existing software. Surface data of the source bones are reconstructed from 3DCT. The trimmed surface data are respectively matched with surface data from the first frame in 4DCT. These trimmed surfaces are sequentially matched until the last frame. These processes provide positional information for target bones in all frames of the 4DCT. Once the coordinate systems of the target bones are decided, translation and rotation angles between any two bones can be calculated. This 4DCT analysis offers advantages in kinematic analyses of complex structures such as carpal or tarsal bones. However, fast or large-scale motions cannot be traced because of motion artifacts.

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A Novel Flow Dynamics Study of the Intracranial Veins Using Whole Brain Four-Dimensional Computed Tomography Angiography

Mizutani K., Arai N., Toda M., Akiyama T., Fujiwara H., Jinzaki M., Yoshida K.

World Neurosurgery （World Neurosurgery） 131 e176 - e185 2019年11月

ISSN 18788750

© 2019 Elsevier Inc. Background: The flow dynamics of the intracranial venous channels are fundamentally important for understanding intracranial physiology and pathophysiology. However, the method clinically applicable to the evaluation of the flow dynamics of the intracranial venous system has not been well described in the reported data. We have developed a new method to evaluate intracranial venous flow direction and velocity using 4-dimensional (4D) computed tomography angiography (CTA). The aim of the present study was to verify the accuracy and validity of 4D-CTA in a clinical setting. Methods: We retrospectively analyzed 97 veins from 26 patients (16 cases of arteriovenous shunt disease, 9 intracranial tumor cases, and 1 cerebral aneurysm case) who had undergone both 4D-CTA and conventional digital subtraction angiography (DSA). Using 4D-CTA, we analyzed the time-density curve with gamma distribution extrapolation and obtained the direction of the flow and flow velocity of each vein. The direction of the flow in 4D-CTA was also collated with that obtained using conventional DSA to verify the experimental method. Results: The direction of the flow determined by 4D-CTA was consistent with that of conventional DSA in 94.8% of cases. The average venous flow velocity was 64.3 mm/second and 81.8 mm/second, respectively, in the antegrade and retrograde channels affected by arteriovenous shunts. Conclusions: The present flow analysis using 4D-CTA enabled us to evaluate the direction and velocity of intracranial venous flow. Other than some limitations, the presented method is reliable and its potential for application in clinical settings is promising.

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特集希少癌に備える-いざという時のための基礎知識後腹膜腫瘍:画像診断

秋田大宇, 池田織人, 陣崎雅弘

臨床泌尿器科（株式会社医学書院） 73 （ 11 ） 806 - 814 2019年10月

ISSN 0385-2393

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