Seismological evidence on characteristic time of crack healing in the shallow crust

金沢大学大学院自然科学研究科自然計測応用センター金沢大学理学部A continuous observation of shear wave splitting for 17 years reveals a unique temporal variation in seismic anisotropy in the shallow crust induced by a larger earthquake (MW5.7) beneath the Tokai region, Japan. The delay time between the fast and slow wavelets coseismically increased and then decreased back to the pre-event value. The duration of the decreasing stage is about two years. The decrease may indicate crack healing in the upper 10 km of the crust. We approximate the temporal variation in the delay time as a function of logarithm of time, which is concordant with healing phenomena of cracks reported by laboratory experiments. The observation indicates that healing of cracks in crustal rocks is complete in approximately two years. Copyright 2005 by the American Geophysical Union

Prediction of common hepatic artery catheter insertion based on celiac trunk morphology

PURPOSEThis study aimed to predict the ability to insert a 4–5 French (Fr) catheter insertion with a guidewire into the common hepatic artery (CHA) based on celiac trunk morphology.METHODSThis retrospective study included 64 patients who underwent balloon-occluded transcatheter arterial chemoembolization (n = 56), transcatheter arterial chemotherapy (n = 2), or were fitted with an implantable port system (n = 6) between June 2019 and December 2019 in our institution. The morphology of the celiac trunk was classified into three types (upward, horizontal, and downward) based on celiac angiography. The aortic–celiac trunk angle was measured on sagittal images of preprocedural contrast-enhanced computed tomography (CT). We reviewed whether a 4–5-Fr shepherd’s hook catheter could advance beyond the CHA using a 0.035-inch guidewire (Radifocus® Guidewire M; Terumo). Three patients were diagnosed with median arcuate ligament syndrome (MALS) based on the characteristic hook shape of the celiac artery on sagittal images of contrast-enhanced CT. The predictive ability of celiac angiography and preprocedural CT for CHA insertion success was evaluated. In unsuccessful cases, the balloon anchor technique (BAT) was attempted as follows: (1) a 2.7/2.8-Fr microballoon catheter (Attendant Delta; Terumo) was placed beyond the proper hepatic artery, and (2) the balloon was inflated as an anchor for parent catheter advancement.RESULTSUpward, horizontal, and downward celiac trunk types were noted in 42, 9, and 13 patients, respectively. The median CT angle was 122.83° (first quartile–third quartile, 102.88°–136.55°). Insertion in the CHA using the guidewire was successful in 56 of 64 patients (87.50%), and the success rate in the downward type was significantly lower than that in the upward type [42/42 (100%) vs. 7/13 (53.85%), P < 0.001]. The CT angle was significantly larger downward in the unsuccessful group than in the successful group (121.03° vs. 140.70°, P = 0.043). Celiac angiography had a significantly higher area under the curve (AUC) than preprocedural CT (AUC = 0.91 vs. AUC = 0.72, P = 0.040). All three cases of MALS showed unsuccessful CHA insertion. In all eight patients with unsuccessful insertion, the catheter could be advanced using the BAT [8/8 (100%)].CONCLUSIONCeliac angiography and preprocedural CT could predict CHA catheter insertion using a guidewire, and celiac angiography had high predictability. CT could detect MALS, a risk factor for unsuccessful CHA insertion

Embolization of pseudoaneurysms in the ureteral branch of the renal artery

Abstract Background Although transcatheter arterial embolization for pseudoaneurysms is already well-established, ureteral artery pseudoaneurysm embolization is extremely rare. The present case shows a successful transcatheter arterial embolization for pseudoaneurysms in the ureteral branch of the renal artery due to ureteral invasion from gastric cancer. Case presentation A 57-year-old female presented with gross hematuria after treatments for poorly differentiated gastric adenocarcinoma. A contrast-enhanced computed tomography revealed pseudoaneurysms around the right ureter with a massive hematoma in the right ureter and bladder. The diagnosis was ureteral branch pseudoaneurysms resulting from possible retroperitoneal invasion due to pelvic lymph node metastasis of gastric cancer. Transcatheter arterial embolization was performed using gelatin particles, successfully controlling her hematuria without complications. Conclusions Ureteral branch artery embolization, although extremely rare, may be an effective and safe treatment option

Secondary Budd-Chiari syndrome occurred after adjuvant radiotherapy for perihilar cholangiocarcinoma: a case report

Abstract Background Budd–Chiari syndrome (BCS) is a rare vascular disorder of the liver, and acute and secondary BCS is even rarer. Case presentation A 62-year-old man with perihilar cholangiocarcinoma of Bismuth type IIIa underwent right hemi-hepatectomy with caudate lobectomy and pancreatoduodenectomy. Adjuvant chemoradiotherapy was performed due to a positive hepatic ductal margin. Subsequently, the disease passed without recurrence. The patient visited for acute onset abdominal pain at the 32nd postoperative month. Multidetector-row computed tomography (MDCT) showed stenosis of the left hepatic vein (LHV) root, which was the irradiated field, and thrombotic occlusion of the LHV. The patient was diagnosed with acute BCS caused by adjuvant radiotherapy. Although anticoagulation therapy was performed, the patient complained of sudden upper abdominal pain again. MDCT showed an enlarged LHV thrombus and hepatomegaly. The patient was diagnosed with exacerbated acute BCS, and stenting for the stenotic LHV root was performed with a bare stent. Although stenting for the LHV root was very effective, restenosis occurred twice due to thrombus in the existing stent, so re-stenting was performed twice. The subsequent clinical course was acceptable without recurrence or restenosis of the LHV root as of 6 months after the last stenting using a stent graft. Conclusion Although no case of BCS caused by radiotherapy has yet been reported, the present case showed that late side effect of radiotherapy can cause hepatic vein stenosis and secondary BCS

Spatial and Temporal variations in the Crustal Anisotropy in the Tokai Region, Central Japan

Spatial and temporal variations in seismic anisotropy in the crust are investigated using earthquakes in the crust and at the upper boundary of the subducting Philippine Sea plate in the Tokai region, central Japan. We use waveform data from December 1986 to August 1999 recorded by the micro-earthquake observation network of the Research Center for Seismology and Volcanology, Nagoya University. The method of Silver and Chan (1991) is applied to evaluate splitting parameters, a leading shear-wave polarized direction and a delay between two polarized waves. A total of 362 high-quality waveform data within the incident angle of 35° are analyzed in this study. The leading shear-wave polarized directions are approximately E-W, in spite of differences of focal depths. This direction is consistent with the direction of regional horizontal maximum compressive stress in the Tokai region reported before. The time delay increases in proportion to the focal depth. These results indicate that the regional compressive stress controls anisotropy not only in the upper crust but also in the lower crust. Assuming the uniform distribution of anisotropy, the degree of anisotropy is estimated to be 0.5% in the lower crust. An increase in time delays between two-polarized waves is found before and after the Aichi-ken Tobu earthquake (M = 5.7) in 1997 at the station STN. This variation is statistically significant with the confidence level of 99.999% and is not an apparent change due to a variation in hypocenter distribution. No temporal variation of splitting parameters is found at the station INU. These results can be explained by a change of the volumetric and areal strain in the most-upper part of the crust due to the postseismic slip of the Aichi-ken Tobu earthquake