鎖骨下動脈閉塞性動脈硬化症に対する血管内超音波評価を併用したステント留置術の長期治療成績

The objective of this study was to determine long-term outcomes after stent placement for subclavian artery (SA) obstructive lesions assisted by intraoperative intravascular ultrasound (IVUS). The study included 25 lesions in 24 patients who underwent stent placement assisted by intraoperative IVUS for subclavian artery stenosis or obstruction at our hospital between January 2003 and August 2010. Outcome was evaluated based on the results within 30 postoperative days (technical success rate, improvement in upper extremity ischemia, steal syndrome, left-right blood pressure difference, and perioperative complications) and the results after 30 postoperative days (incidence of vertebrobasilar artery territory infarction and restenosis). Stent placement and vessel dilatation were successful in all patients, without perioperative complications. Upper extremity ischemia, steal syndrome, and left-right blood pressure difference disappeared in all cases. During follow-up observation (6-96 months; median 51 months), no restenosis occurred at the stent placement site in any patient. In one case, four years after initial treatment, stenosis was noted proximal to the stent placement site. Satisfactory long-term as well as short-term outcomes were achieved after stent placement for SA obstructive lesions assisted by intraoperative IVUS evaluation.博士（医学）・乙第1362号・平成27年5月28日Copyright © 2014 by SAGE Publications. The definitive version is available at " http://dx.doi.org/10.15274/NRJ-2014-10023

不安定プラークを伴った頚動脈狭窄症に対するクローズセルステントを用いたステントインステント法による頚動脈ステント留置術

Purpose: To examine whether carotid artery stenting (CAS) of stenoses with unstable plaque using a closed-cell stent-in-stent technique prevents plaque protrusion. Materials and Methods: Between December 2014 and August 2018, 35 consecutive patients (mean age 75.8 years; 29 men) with carotid artery stenosis (20 symptomatic) and unstable plaque diagnosed by magnetic resonance imaging were prospectively analyzed. Mean diameter stenosis was 83.5%. All CAS procedures were performed with stent-in-stent placement of Carotid Wallstents using an embolic protection device and conservative postdilation. The technical success rate, incidence of plaque protrusion, ischemic stroke rate within 30 days, and new ipsilateral ischemic lesions on diffusion-weighted imaging (DWI) within 48 hours after CAS were prospectively assessed. Follow-up outcomes included the incidences of ipsilateral stroke and restenosis. Results: The technical success rate was 100%. No plaque protrusion or stroke occurred in any patient. New ischemic lesions were observed on DWI in 10 (29%) patients. During the mean 11.6-month follow-up, no ipsilateral strokes occurred. Two (6%) patients developed asymptomatic restenosis recorded as 53% lumen narrowing and occlusion, respectively. Conclusion: CAS using a closed-cell stent-in-stent technique for unstable plaque may be useful for preventing plaque protrusion and ischemic complications.博士（医学）・乙第1444号・令和元年12月5日This is a non-final version of an article published in final form in "https://doi.org/10.1177/1526602819847698

Application of susceptibility weighted imaging (SWI) for evaluation of draining veins of arteriovenous malformation: utility of magnitude images.

INTRODUCTION: The current study evaluated the signal characteristics of susceptibility weighted imaging (SWI) of arteriovenous malformation (AVM), especially for draining veins. For this purpose, we identified the draining veins of the AVM on angiography and evaluated the signal on magnitude image for SWI (SWI-mag) and minimum intensity projection image (SWI-minIP). METHODS: Subjects were 14 cases with angiographically proven AVM. SWI-mag, SWI-minIP, and time-of-flight (TOF) magnetic resonance angiography were acquired. For the draining veins of the AVM identified on angiography, we analyzed signal intensity on the images listed above, and classified it into hyperintensity (hyper), mixed intensity (mixed), hypointensity (hypo), and no visualization. RESULTS: On the analysis of 27 angiographically proven draining veins, 19 draining veins were classified as hyper, 3 as mixed, 0 as hypo, and 6 as no visualization on SWI-mag. On TOF images, 21 draining veins were classified as hyper, 2 as mixed, 0 as hypo, and 4 as no visualization, while 6 draining veins did not show hyperintensity on TOF, and SWI-mag visualized 3 of these 6 veins as hyper. CONCLUSION: SWI-mag depicted most draining veins of AVM as hyperintensity. We speculate that this is mainly due to the higher concentration of oxygenated hemoglobin (oxy-Hb) and inflow effect of the draining vein. SWI-mag seems to be useful in the analysis and follow-up for AVM as the signal on the image may reflect physiological status.博士（医学）・乙第1316号・平成25年7月22

T1強調像での信号強度が出生後日数と負の相関性を示す新生児・乳児期の脳構造

Purpose: Although the neonatal and infantile brain typically shows sequential T1 shortening according to gestational age as a result of myelination, several structures do not follow this rule. We evaluated the relationship between the signal intensity of various structures in the neonatal and infantile brain on T1-weighted imaging (T1WI) and either postnatal or gestational age. Materials and Methods: We examined magnetic resonance images from 120 newborns and infants without any abnormalities in the central nervous system. Written informed consent was obtained from all parents and the institutional review board approved the study. Gestational age at examination ranged from 35 weeks, 3 days to 46 weeks, 6 days, and postnatal age ranged from 7 days to 127 days. Signal intensity on T1WI was evaluated on a scale from Grade 1 (indistinguishable from surrounding structures) to Grade 4 (higher than cortex and close to fat). We evaluated relationships between the T1 signal grades of various structures in the neonatal brain and postnatal or gestational age using Spearman’s correlation analysis. Results: Significant positive correlations were identified between T1 signal grade and gestational age in the pyramidal tract (P < 0.001). Conversely, significant negative correlations were evident between T1 signal grade and postnatal age (P < 0.001), in structures including the stria medullaris thalami, fornix cerebellar vermis, dentate nucleus and anterior pituitary gland. Conclusion: Significant negative correlations exist between signal intensity on T1WI and postnatal age in some structures of the neonatal and infantile brain. Some mechanisms other than myelination might play roles in the course of signal appearance.博士（医学）・乙第1405号・平成29年6月28日Copyright © 2017 by Japanese Society for Magnetic Resonance in Medicine : This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives International License(https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja)

Optimization of scan timing for aortic computed tomographic angiography using the test bolus injection technique

Background: With fast computed tomography (CT), it is possible for the scanning to outpace the contrast medium bolus during aortic CT angiography (CTA). Purpose: To evaluate the effectiveness of a new method for reducing the risk of outpacing in which the scan start timing (ST) and speed can be estimated from the peak enhancement time measured at the femoral artery using a single testbolus injection (femoral artery test injection method [FTI method]). Material and Methods: In 30 cases of aortic CTA, we measured the time to peak enhancement at the femoral artery (TPF) and the ascending aorta (TPA) with test-bolus injection performed twice in each examination. From the resultant linear relationship between TPF and transit time (TTTPF=TPA), we developed a method for determining the ST and TT from TPF. One hundred patients were assigned to two groups: FTI and bolus tracking (BT), each with 50 patients. CT values were measured in main vessels (ascending aorta, descending aorta, femoral artery). The CT values of the vessels and the rate of cases with more than 300 HU (good cases) were compared between the two groups. Results: The enhancement in the FTI method was significantly higher than that of the BT method (average CT values: FTI, 388.352.4; BT, 281.259.1; P<0.001). The rates of good cases for FTI and BT were 86.0% and 46.0%, respectively. Conclusion: The FTI method was very effective in reducing the risk of outpacing of the contrast medium transit in aortic CTA without the need for an additional contrast medium dose. © The Foundation Acta Radiologica 2015.Embargo Period 12 month

ラット凍結肩モデルを用いた経カテーテル的動脈塞栓術の効果に関する検討

Purpose: To assess the angiographic findings and the effects of transcatheter arterial embolization on physical activity and histopathology using a frozen shoulder rat model. Materials and methods: First, the angiographic and histopathologic findings of rats in which the shoulder was immobilized with molding plaster for 6 weeks (n = 4) were compared to control rats with normal non-immobilized shoulders (n = 4). Next, a total of 16 frozen shoulder rats were divided into 2 groups. In the transcatheter arterial embolization group (n = 8), imipenem/cilastatin was injected into the left thoracoacromial artery. The changes of physical activity before and after procedures were evaluated and compared with a saline-injected control group (n = 8). Histopathologic findings were also compared between the 2 groups. Results: Angiography revealed abnormal shoulder staining in all of the rats with a frozen shoulder. On histopathology, the numbers of microvessels and mononuclear inflammatory cells in the synovial membrane of the joint capsule were significantly higher compared with the control rats (both P = .03). In the transcatheter arterial embolization group, the running distance and speed were improved (P = .03 and P = .01, respectively), whereas there were no significant differences in the control group. The number of microvessels and mononuclear inflammatory cells in the transcatheter arterial embolization group were significantly lower than the control group (P = .002 and P = .001, respectively). Conclusions: The rat frozen shoulder model revealed the development of neovascularization. Transcatheter arterial embolization decreased the number of blood vessels and inflammatory changes in the frozen shoulder and increased the moving distance and speed of the rats.博士（医学）・甲第789号・令和3年3月15日Copyright © 2020 SIR(Society of Interventional Radiology). Published by Elsevier Inc. All rights reserved