Four-dimensional flow magnetic resonance imaging for assessment of hemodynamic changes in the portal venous system before and after balloon-occluded retrograde transvenous obliteration: a pilot feasibility study.

BACKGROUND: The effectiveness of four-dimensional (4D) flow magnetic resonance imaging (MRI) for assessing hemodynamic changes before and after balloon-occluded retrograde transvenous obliteration (BRTO) remains unclear. PURPOSE: To evaluate the feasibility of 4D flow MRI for assessing hemodynamic changes in the portal venous system before and after BRTO. MATERIAL AND METHODS: We included 10 patients (7 men, 3 women; mean age = 67 years) with liver cirrhosis who had a high risk of gastric variceal bleeding or hepatic encephalopathy. Non-contrast 4D flow MRI of the upper abdomen was performed before and after BRTO. In addition, we compared the blood flow rates in the portal vein (PV), superior mesenteric vein (SMV), splenic vein (SV), left renal vein, and inferior vena cava before and after BRTO. Moreover, the flow directions of the SMV and SV before and after BRTO were assessed using both portography and 4D flow MRI. RESULTS: There was a significant post-BRTO increase in the blood flow rate in the PV and SV (P < 0.05). There was no significant post-BRTO change in the blood flow rates in the SMV, inferior vena cava, and left renal vein. In four patients, portography confirmed that hepatofugal flow in the SV and SMV changed to hepatopetal flow after BRTO. Moreover, 4D flow MRI correctly assessed the flow directions in the SMV and SV in 70%-100% of the patients. CONCLUSION: 4D flow MRI can be used to detect hemodynamic changes in the portal venous system before and after BRTO.

Spontaneous portosystemic shunt diameter predicts liver function after balloon-occluded retrograde transvenous obliteration.

BACKGROUND AND AIM: Recently, balloon-occluded retrograde transvenous obliteration (BRTO), performed for spontaneous portosystemic shunts (SPSS), has been receiving attention as a measure to improve liver function in cirrhotic patients with portal hypertension. However, it is unclear whether SPSS diameter is associated with changes in hepatic venous pressure gradient (HVPG) and liver function after BRTO. METHODS: In 34 cirrhotic patients receiving BRTO for hepatic encephalopathy/gastric varices, the association of SPSS diameter with liver function at baseline and 6 months after BRTO and the accompanying changes in HVPG were investigated. RESULTS: Patients had Child-Pugh (CP) scores of A/B/C (7/19/8), SPSS diameters of ≤10 mm/11-20 mm/<20 mm (8/21/5), and an average observation period of 3.2 (0.3-8.5) years. SPSS diameter was significantly associated with male sex, alcohol use, and values of albumin, prothrombin time (PT%), and NH3 at baseline. Moreover, the SPSS diameter was significantly correlated with the changes in HVPG observed upon BRTO (r = 0.55, P = 0.005), and a large shunt diameter was significantly associated with a greater increase in HVPG. At 6 months, significant improvements in albumin, PT%, bilirubin, and NH3 were observed overall, but the improvement was marked in those with larger shunt diameters if they had CP A/B. CONCLUSION: SPSS diameter was strongly associated with liver function at baseline and after BRTO and also with changes in HVPG, indicating that SPSS diameter is an important predictor of BRTO outcome.

Anatomy of Left Inferior Phrenic Vein in Patients Without Portal Hypertension.

OBJECTIVE. The left inferior phrenic vein (LIPV) can be an origin of a gastrorenal shunt from gastric varices. The purpose of our study was to evaluate the angiographic anatomy of the LIPV, particularly anastomoses of the LIPV with the portal vein (PV). SUBJECTS AND METHODS. Of 240 patients with primary aldosteronism who underwent adrenal venous sampling from April 2011 to July 2019, 236 had normal liver and renal function and were included in this study. Of those patients, 214 had evaluable LIPV venography. The angiographic anatomy of the LIPV was classified as type 1 when the subdiaphragmatic transverse part of the LIPV could be visualized or as type 2 when it could not. Type 1 was subclassified into type 1a, which was defined as the transverse part of the LIPV connected with a single vein, or type 1b, which was defined as the transverse part of the LIPV connected with several veins via anastomoses. Type 2 LIPVs were subclassified into type 2a, in which the LIPV had an undeveloped vertical part; type 2b, in which the LIPV had backflow into systemic veins; or type 2c, in which the LIPV had a connection to the PV. The presence of an anastomosis with the PV was defined as the PV being visualizable on LIPV venography. RESULTS. Assessment of LIPV venography revealed type 1 in 71.5% (153/214) of patients, including type 1a (22.4%, 48/214) and type 1b (49.1%, 105/214). Type 2 LIPVs were observed in 28.5% (61/214) of patients, including types 2a (6.5%, 14/214), 2b (11.2%, 24/214), and 2c (10.7%, 23/214). An anastomosis of the LIPV with the PV was found in 28.0% (60/214) of patients, including 10.7% (23/214) with type 2c and 17.3% (37/214) with type 1 with a visible PV. The anastomoses of the LIPV with the PV were of various sizes. CONCLUSION. The angiographic anatomy of the LIPV varied and was commonly formed from several veins connected by anastomoses. An anastomosis between the LIPV and PV, which might be the origin of gastric varices, was found in 28.0% of patients.

Transarterial fiducial marker implantation for CyberKnife radiotherapy to treat pancreatic cancer: an experience with 14 cases.

PURPOSE: The purpose of this study was to evaluate the safety and feasibility of transarterial fiducial marker implantation for CyberKnife radiotherapy to treat locally advanced pancreatic cancer. MATERIALS AND METHODS: Fifteen pancreatic cancer patients were enrolled for transarterial marker implantation. Embolization platinum coils were implanted as a fiducial marker within 20 mm of the cancer edge, and preferably within 3 mm. The technical success of the implantation was defined as implantation of at least one fiducial marker within 20 mm of the target tumor. Irradiation was performed using the CyberKnife system. RESULTS: For 14 of 15 patients, transarterial implantation was successfully performed, and for 13 of 14 patients, the tracking marker was implanted within 3 mm of the cancer. Tracking instability was observed in two patients, but irradiation was accomplished in all 14 patients. No major complications caused by the implantation procedure were observed. The median overall survival after irradiation was 13.8 months, and the 1- and 2-years survival rates were 62.9% and 32.3%, respectively. CONCLUSION: Transarterial fiducial marker implantation for pancreatic cancer can be safely performed for tracking, and it will be a valuable alternative approach to percutaneous fiducial marker implantation.

Does catheter shape influence the success of right adrenal venous sampling? The interaction of catheter shape to anatomical factors on CT.

PURPOSE: To evaluate the importance of selecting an appropriate catheter shape for the right adrenal vein (RAV) anatomy on CT to the success of right adrenal venous sampling (RAVS) by elucidating the interactions of anatomical factors with catheter shape. MATERIALS AND METHODS: 130 patients with enhanced CT underwent RAVS using two catheters: catheter 1 was planar and catheter 2 was a three-dimensional shape. The following anatomical factors on CT were evaluated in each patient: presence of a right adrenal tumor, presence of a common trunk with an accessory right hepatic vein, diameter of the RAV, short and long diameters of the IVC, ratio of the long to the short diameter of IVC, and the transverse, modified transverse, and vertical angles of the RAV. RAVs were classified by direction on CT as lateral-caudal, lateral-cranial, medial-caudal, or medial-cranial. The technical feasibility of each catheter was evaluated by intragroup analysis. RESULTS: 108 patients underwent technically successful RAVS with one or both catheters. Eight of the 22 patients in whom RAVS was not successfully achieved by either catheter within ten minutes required microcatheters; other catheters were used in the other 14. The factors that were found to be associated with RAVS success were the modified transverse and the vertical angles (p < 0.01) of RAV on CT. Catheters 1 and 2 provided stable sampling in the lateral-caudal and medial groups, respectively. CONCLUSION: Adapting the shape of the catheter to the anatomy of the RAV can make RAVS more feasible. The anatomical factors that were found to be associated with RAVS success were the transverse angle modified by the IVC axis as well as the vertical angle of RAV on CT.

Can microcatheters be cleaned for reuse after NBCA embolization? Cleaning technique with gelatin sponge particles.

PURPOSE: To study a new technique for cleaning microcatheters for reuse after NBCA embolization ("NBCA"), and to evaluate the clinical reusability of microcatheters that were cleaned with gelatin sponge particles after NBCA. MATERIALS AND METHODS: Four cleaning solution flushes for microcatheters after NBCA injection-5 % glucose ("glucose") only, Lipiodol-glucose, gelatin sponge particles ("gelatin")-glucose, and Lipiodol-gelatin-glucose-were examined experimentally. These solutions were evaluated by performing three examinations: a microcatheter resistance test based on the time taken to pass water through the microcatheter, a microcatheter resistance test based on the ease of insertion of a microguidewire, and observations of the inner surfaces of the cylinders after NBCA. Microcatheters that had already been used in NBCA were cleaned using this new technique and then applied in 20 clinical sessions (19 patients). RESULTS: There was no significant difference in water passage time between the controls and the groups that received a gelatin flush. In the resistance test based on the insertion of a microguidewire, groups that received a gelatin flush showed significantly less resistance than the groups that did not receive a gelatin flush. Observations of the inner surfaces of the cylinders indicated that cleaning with gelatin can lead to inner surfaces that are almost indistinguishable from control surfaces in terms of cleanliness. All clinical procedures involving Lipiodol-gelatin-glucose flushes were performed without any technical difficulties or complications. CONCLUSIONS: Applying the new cleaning technique utilizing gelatin sponge particles to microcatheters after NBCA ensures that they are clean enough to be reused.

Abdominal pressing maneuver during adrenal venous sampling for stabilization of catheter position.

PURPOSE: The abdominal pressing maneuver (APM) is to control respiration movement of the right adrenal vein (RAV) during adrenal venous sampling (AVS). Instability of a catheter inserted into the RAV due to respiration movement can be a factor contributing to the unfeasibility of AVS. MATERIALS AND METHODS: Sixty-five consecutive patients who underwent AVS for primary aldosteronism were enrolled. We measured distances (D) of respiration movement of the RAV both without and with APM in patients who were resting breathing (n = 30) or deep breathing (n = 35). This method was clinically applied on 37 patients in whom the catheter became disconnected from the RAV either during venography or when collecting blood caused by respiration movement. RESULTS: The average values for D-resting without APM and D-resting with APM were 7.6 (SD 2.5) and 3.6 (SD 1.7) mm, respectively, which was significantly different. The average values for D-deep without APM and D-deep with APM were 16.3 (SD 5.2) and 8.6 (SD 3.8) mm, which was also significantly different. The average control rates under conditions of deep or resting breathing were 45% [SD 17% (median 43%)] and 50% [SD 19% (median 49%)], respectively. The catheter was stable in 33 (88%) of 37 patients while using the APM. CONCLUSION: The APM is considered convenient and feasible for successfully controlling respiration movement in patients undergoing AVS.

Enhancement of ascites during abdominal oncological endovascular intervention without iatrogenic extravasation in patients with chronic liver disease.

AIM: To evaluate ascites enhancement during abdominal oncological endovascular intervention (IVR) without iatrogenic extravasation and the factors associated with enhancement of ascites. METHODS AND MATERIALS: CT images were obtained using an IVR-CT system for 73 patients with chronic liver disease and ascites. The CT images were obtained at least twice during each IVR. Radiodensity values of ascites at CT were measured for the first and last CT images in each procedure. The factors evaluated for their association with elevated ascitic fluid density were age, interval from the first to the last CT scan, Child-Pugh score, albumin level, total bilirubin level, prothrombin activity, the need for transcatheter arterial chemoembolization (TACE), estimated glomerular filtration rate, total amount of contrast material (CM) per square metre of body surface area (/m(2)), amount of ascitic fluid, and the amount of CM entering the superior mesenteric artery (SMA) or coeliac artery/m(2). RESULTS: The average ascitic radiodensity values for the first and last CT images were 18 and 51 HU, respectively. The percentage of patients with "significantly elevated" ascitic fluid density (≥10 HU) was 92%. Multivariate analysis showed that the total amount of CM/m(2) and the amount of ascitic fluid were significantly correlated and inversely correlated, respectively, with elevated ascitic fluid density. CONCLUSIONS: Ascites enhancement without extravasation frequently occurs during abdominal oncological endovascular intervention in patients with chronic liver disease.

Balloon-occluded retrograde transvenous obliteration of gastric varices from unconventional systemic veins in the absence of gastrorenal shunts.

Balloon-occluded retrograde transvenous obliteration of gastric varices in the absence of a gastrorenal shunts can still be performed through unconventional venous routes, such as the left inferior phrenic (ascending portion or transverse portion), pericardial, and azygous-hemiazygous veins. This requires detailed knowledge of venous anatomy, impeccable preprocedural imaging for planning, and high-skill set techniques with smaller balloon-occlusion catheters. The technical results appear to be high (67%-83% depending on the access venous system available), but are lower than conventional balloon-occluded retrograde transvenous obliteration via the gastrorenal shunt.

Can balloon-occluded retrograde transvenous obliteration be performed for gastric varices without gastrorenal shunts?

PURPOSE: To evaluate the feasibility for balloon-occluded retrograde transvenous obliteration (BRTO) for gastric varices without gastrorenal shunts. MATERIALS AND METHODS: Of 76 patients with gastric varices who were referred for treatment by BRTO, 11 did not have gastrorenal shunts. Contrast medium-enhanced computed tomography (CT) was performed in all patients; seven patients also underwent CT during splenic arteriography. BRTO was performed to insert a balloon catheter into the main draining vein and inject 5% ethanolamine oleate into gastric varices under the temporary balloon occlusion. RESULTS: The main draining veins were the subphrenic transverse part of the inferior phrenic vein to the inferior vena cava in five patients, the pericardial vein to the left brachiocephalic vein in two, and the paraesophageal vein to the azygos vein in two. In two patients, the main draining vein was unknown. The overall success rate of BRTO in the nine cases with main draining veins was 67%; BRTO was successful in four of the patients in whom the inferior phrenic vein was the main draining vein, one of the patients in whom the pericardial vein was the main draining vein, and one of the patients in whom the paraesophageal vein was the main draining vein. In the other cases in which the inferior phrenic vein or pericardial vein was the main draining vein, BRTO could not be performed because of extravasation. In another patient in whom the paraesophageal vein was the main draining vein, the main draining pathway could not be identified at angiography because of a complicated azygos venous network. CONCLUSIONS: It is feasible to use BRTO to treat cases of gastric varices in which the inferior phrenic vein is the main draining vein. Cases in which the main draining pathway is the pericardial vein are less feasibile for BRTO. The use of BRTO in cases in which the paraesophageal vein is the main draining vein is possible but may be difficult because of a complicated venous network.

Endovascular treatment of ureteroarterial fistulas with stent-grafts.

Ureteroarterial fistula is a rare condition with life-threatening hematuria that should be diagnosed and treated immediately. We reported two patients of ureteroarterial fistula who underwent successful endovascular treatment by stent-grafts. They had undergone pelvic surgery followed by placement of an indwelling ureteral stent for stricture of the ureter before sudden hematuria occurred. Routine contrast-enhanced computed tomography did not reveal extravasation or a pseudo-aneurysm. Angiograms with multiple oblique views demonstrated small pseudoaneurysms of the iliac artery overriding the ipsilateral ureter. The endovascular treatment of ureteroarterial fistula using stent-grafts was successful, and the hematuria disappeared immediately after stent-graft deployment. The hematuria did not recur up to the last follow-up visits of 3 and 19 months, respectively.

MR-guided intravascular catheter manipulation: feasibility of both active and passive tracking in experimental study and initial clinical applications.

PURPOSE: To evaluate clinically the feasibility and usefulness of MR-guided intravascular procedures with either active or passive tracking. METHODS: With an active MR tacking system and a 0.2 Tesla open MR imager, real-time and biplane displays of positions of a receive-only coil at the tip of catheters were obtained. For passive tracking, 4 Fr catheters with suitable susceptibility for passive tracking were used. Passive tracking with a 1.5 Tesla MR imager could be performed with parameters of TR 15-50 msec, TE 2.2-2.7 msec, and FA 30 degrees. The temperature of each tracking catheter was monitored in vitro. Clinical trials were performed on six patients (three each). The catheter was introduced to the superior mesenteric artery (SMA) under MR guidance by active or passive tracking to perform MR imaging during arterial portography. RESULTS: The temperature increased minimally. In humans, the SMA and celiac artery could be easily introduced on active tracking. MR-guided manipulation of catheters by active or passive tracking in the model and in dogs' vessels was very successful. Introduction of the catheter into the SMA was successful in two cases of active tracking and in all cases of passive tracking. CONCLUSION: The MR-guided intravascular manipulation of catheters by active or passive tracking may be a clinically feasible method.