著者

Satoshi Kobayashi Toshiya Osanai Taku Sugiyama Noriyuki Fujima Ryo Takagi Isao Yokota Akiyoshi Hamaguchi Toshitaka Nakamura Kazutoshi Hida Miki Fujimura

出版者

The Japanese Society for Neuroendovascular Therapy

雑誌

Journal of Neuroendovascular Therapy (ISSN:18824072)

巻号頁・発行日

pp.oa.2023-0001, (Released:2023-05-17)

参考文献数

20

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Objective: In endovascular treatment, it is important to evaluate the access route for placing a catheter into the common carotid artery (CCA) promptly and safely prior to the procedure. We examined whether non-contrast MRA using time-spatial labeling inversion pulse (Time-SLIP) can be used in patients prior to endovascular thrombectomy for acute ischemic stroke. We compared Time-SLIP MRA to contrast-enhanced (CE) MRA and evaluated the efficacy in the evaluation of access routes.Methods: We retrospectively reviewed 31 patients admitted between October 2018 and December 2018 for cerebral infarction at our hospital. Blood vessels were imaged from the aortic arch to the CCA. A radiologist blindly evaluated quality score, stenosis, shape of the aorta, and degree of tortuosity.Results: There were no “non-diagnostic” images. The sensitivity, specificity, positive predictive value, and negative predictive value for stenosis were 83%, 96%, 83%, and 96%, respectively. The sensitivity for the aorta type classification was 100%. The sensitivity for mild tortuosity was 93%, for moderate was 100%, and for severe was 100%.Conclusion: Time-SLIP MRA can be an alternative to CE MRA in access route assessment for patients with cerebral infarction who are not eligible for acute thrombectomy therapy.

著者

Satoshi Kobayashi Miguel Vazquez Archdale

出版者

Carcinological Society of Japan

雑誌

Crustacean Research (ISSN:02873478)

巻号頁・発行日

vol.51, pp.17-29, 2022-02-01 (Released:2022-02-01)

参考文献数

38

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This is the first record of the burrows of the Japanese mitten crab Eriocheir japonica. Morphologies of the burrows found in the clay sediment used by this crab were recorded by excavating them in a small freshwater river in Japan. Only E. japonica was found inside 2 of the 10 burrows examined (15 crabs and one crab, respectively), and the other 8 were empty. Crabs of various sizes (6.1–47.0 mm in carapace width) were collected from inside the occupied burrows. Burrow morphology ranged from single tunnels to complex burrows with multiple openings and tunnels. Openings (2–10 cm in diameter) were mostly located underwater. The single tunnels were 14–65 cm long. Considering the different digging habits of other burrowing animals found in this area, it can be concluded that E. japonica constructed these burrows. Burrows resembled those of the Chinese mitten crab E. sinensis, but were different in their location (freshwater vs. tidal), sediment type (clay vs. sand and silt), opening placement (mainly underwater vs. intertidal) and occupation rate (low vs. high). The low occupation rate suggests that E. japonica do not always rest in their burrows and rather prefer to hide beneath the riverbed’s large rocks. These results reflect the adaptation of E. japonica to the unstable environment of Japanese rivers.

著者

Naoki Ohno Kotaro Yoshida Yu Ueda Yuki Makino Tosiaki Miyati Toshifumi Gabata Satoshi Kobayashi

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2021-0087, (Released:2021-11-02)

参考文献数

26

被引用文献数

5

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Purpose: This multi-scanner study aimed to investigate the validity of single breath-hold (BH) diffusion-weighted imaging (DWI) using simultaneous-multislice (SMS) echo-planar imaging in multiple abdominal organs to enable faster acquisition and reliable quantification of apparent diffusion coefficient (ADC).Methods: SNR, geometric distortion (GD), and ADC in a phantom; the ADC in the liver, renal cortex, paraspinal muscle, spleen, and pancreas; and the signal intensity ratio of the portal vein-to-muscle (SIRPV-M) in healthy volunteers were compared between BH- and respiratory-triggered (RT) DWI with b-values of 0 and 800 s/mm2 in two different MRI scanners.Results: The phantom study showed that the SNR of BH-DWI was significantly lower than that of the RT-DWI (P < 0.05 for both scanners), whereas the GD and ADC of BH-DWI did not differ significantly from those of the RT-DWI (P = 0.09–0.60). In the volunteer study, the scan times were 23 seconds for BH-DWI and 184±33 seconds for RT-DWI, respectively. The ADC of the liver in BH-DWI was significantly lower than that in RT-DWI (P < 0.05 for both scanners), whereas there were no significant differences in the ADCs of the renal cortex, paraspinal muscle, spleen, or pancreas between BH-DWI and RT-DWI (P = 0.07–0.86). The SIRPV-M in BH-DWI was significantly smaller than in RT-DWI (P < 0.05 for both scanners).Conclusion: The proposed method enables the acquisition of abdominal diffusion-weighted images in a single BH.

著者

Yasuo Takatsu Masafumi Nakamura Satoshi Kobayashi Tosiaki Miyati

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2020-0050, (Released:2020-05-27)

参考文献数

21

被引用文献数

3

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Purpose: To investigate whether the contrast enhancement effect in hepatobiliary phase (HBP) images can be predicted using transitional phase (3-min delay) images on liver magnetic resonance imaging (MRI) based on the quantitative liver–spleen contrast ratio (Q-LSC) and albumin–bilirubin (ALBI) grade.Methods: Overall, 212 patients (124 men and 88 women; mean age 66.7 ± 11.1 years) who underwent blood tests (assessed within 1 month of performing MRI) were included; patients with diffuse tumor, hepatectomy, splenectomy, Gamna–Gandy bodies in the spleen, and movement artifacts were excluded. Q-LSC was calculated using the signal intensity of the liver divided that of the spleen. Q-LSC > 1.5 (cut-off value) indicates a relatively higher sensitivity for detecting of hepatic lesions. To predict the contrast enhancement effect in HBP using Q-LSC of 3-min delay images, Q-LSC of 10- and 15-min delay images were compared for each ALBI grade based on Q-LSC of 3-min delay images. Furthermore, to verify the accuracy of this prediction, the proportion of cases with Q-LSC > 1.5 in 10- and 15 min delay images was calculated based on Q-LSC on 3-min delay images.Results: The higher the Q-LSC on the 3-min delay image, the higher was the Q-LSC on its 10- and 15-min delay images. The proportion of cases with Q-LSC > 1.5 in 10- and 15-min delay images was higher for ALBI grade 1 than for ALBI grades 2 and 3 even in the same Q-LSC on 3-min delay images. Q-LSC was <1 in a 3-min delay image and <1.5 in a 15-min delay image in 62.2% of patients with ALBI grade 1 and 82.1% of patients with ALBI grades 2 and 3.Conclusion: The liver contrast enhancement effect in HBP images could be predicted using a 3-min delay image based on Q-LSC and ALBI grade.

著者

Masako Ohno Naoki Ohno Tosiaki Miyati Hiroko Kawashima Kazuto Kozaka Yukihiro Matsuura Toshifumi Gabata Satoshi Kobayashi

出版者

Japanese Society for Magnetic Resonance in Medicine

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2020-0103, (Released:2021-02-09)

参考文献数

50

被引用文献数

3

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Purpose: To obtain detailed information in breast ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) using triexponential diffusion analysis.Methods: Diffusion-weighted images (DWI) of the breast were obtained using single-shot diffusion echo-planar imaging with 15 b-values. Mean signal intensities at each b-value were measured in the DCIS and IDC lesions and fitted with the triexponential function based on a two-step approach: slow-restricted diffusion coefficient (Ds) was initially determined using a monoexponential function with b-values > 800 s/mm2. The diffusion coefficient of free water at 37°C was assigned to the fast-free diffusion coefficient (Df). Finally, the perfusion-related diffusion coefficient (Dp) was derived using all the b-values. Furthermore, biexponential analysis was performed to obtain the perfusion-related diffusion coefficient (D*) and the perfusion-independent diffusion coefficient (D). Monoexponential analysis was performed to obtain the apparent diffusion coefficient (ADC). The sensitivity and specificity of the aforementioned diffusion coefficients for distinguishing between DCIS and IDC were evaluated using the pathological results.Results: The Ds, D, and ADC of DCIS were significantly higher than those of IDC (P < 0.01 for all). There was no significant correlation between Dp and Ds, but there was a weak correlation between D* and D. The combination of Dp and Ds showed higher sensitivity and specificity (85.9% and 71.4%, respectively), compared to the combination of D* and D (81.5% and 33.3%, respectively).Conclusion: Triexponential analysis can provide detailed diffusion information for breast tumors that can be used to differentiate between DCIS and IDC.