Yasufumi Ohuchi

Transcatheter Arterial Embolization of Acute Arterial Bleeding in the Upper and Lower Gastrointestinal Tract with N-Butyl-2-Cyanoacrylate

PURPOSE To assess the clinical utility and safety of transcatheter arterial embolization with N-butyl-2-cyanoacrylate (NBCA) for urgent control of acute arterial bleeding in the upper and lower gastrointestinal tract. MATERIALS AND METHODS Therapeutic NBCA embolization was performed in 37 patients (39 cases; mean age, 67.8 years) with acute upper (n = 16) or lower (n = 23) gastrointestinal tract bleeding after endoscopic management had failed. Transcatheter arterial embolization was performed using 1:1 to 1:5 mixtures of NBCA and iodized oil. The most common etiologies of bleeding were colonic diverticulosis (n = 13), malignancy (n = 11), and benign ulcer (n = 7). Coagulopathy was present in 11 patients, and 23 patients were hemodynamically unstable before NBCA embolization. Histologic examination for bowel ischemia was also performed in five patients who underwent excision of the lesion after NBCA embolization. RESULTS The technical success rate was 100%. Recurrent bleeding occurred in two patients. Complete hemostasis was achieved in all 11 patients with coagulopathy. Ulcers induced by transcatheter arterial embolization were noted in 6 of 20 patients who underwent endoscopic examination; the ulcers were successfully treated with conservative measures. Histologic examination revealed that despite inflammatory reactions in and around the vessels, no intestinal necrosis secondary to NBCA embolization was found. Hepatic abscess occurred in two cases, and ischemia of the lower limb occurred in one case; these complications were managed by percutaneous drainage and bypass surgery. CONCLUSIONS Transcatheter arterial embolization with NBCA is a good treatment option with a high rate of complete hemostasis and a low recurrent bleeding rate, even in patients with coagulopathy.

Heat Distribution in the Spinal Canal during Radiofrequency Ablation for Vertebral Lesions : Study in Swine

PURPOSE To prospectively evaluate the safety of radiofrequency (RF) ablation for vertebral lesions by monitoring the temperature in swine vertebral models with and without a cortical bone defect. MATERIALS AND METHODS The institutional animal care and use committee approved the animal studies. In vivo and ex vivo studies were performed. In the in vivo study, 20 lumbar vertebrae from six swine were locally heated by using 1- or 2-cm active-tip internally cooled electrodes. In the ex vivo study, 12 fresh pig cadaver lumbar vertebrae were extracted from four swine, and spinal tumor models with or without cortical bone defect were created by stuffing a cavity with muscle tissue and locally heated by using a 1-cm active-tip internally cooled electrode. The temperature was monitored in the spinal canal and around the vertebral body during ablation. Mann-Whitney U test was used to indicate a significant difference between groups by using 1- and 2-cm active tip in the in vivo study and between groups with and without cortical defect in the ex vivo study. RESULTS In the in vivo study in which 1- and 2-cm active-tip needles were used, the temperature in the spinal canal rose to 38.2 degrees C +/- 2.7 (standard deviation) and 45.5 degrees C +/- 6.2, respectively. The latter was significantly higher than the former (P < .001). In the ex vivo study in which tumor models with or without a cortical bone defect were used, the temperature in the spinal canal rose to 48.4 degrees C +/- 6.2 and 31.3 degrees C +/- 3.4, respectively. The former was significantly higher than the latter (P < .001). CONCLUSION For in vivo cases with a 2-cm active tip and ex vivo cases with a vertebral posterior bone defect, the temperature rose to over 45 degrees C, potentially injuring the spinal cord and peripheral nerves.

Chondroitin Sulfate Iron Colloid as MR Contrast Agent in Differentiation between Hepatocellular Carcinoma and Adenomatous Hyperplasia

Using a 1.5 T MR imaging unit, T1- and T2-weighted images were obtained before and after i.v. administration of chondroitin sulfate iron colloid (CSIC) in order to differentiate hepatocellular carcinoma (n = 20) from adenomatous hyperplasia without atypia (n = 16). Differentiation was made from the tumor-liver contrast to noise ratio (CNR) and visual evaluation of the nodule, with reference to signal intensity relative to that of the surrounding liver. The CNR of adenomatous hyperplasia was on T1-weighted images significantly decreased after CSIC administration (p < 0.01). On T2-weighted images, there was no significant difference in CNR after CSIC administration. On the other hand, the CNR of hepatocellular carcinoma was significantly increased after CSIC administration on both T1- and T2-weighted images (p < 0.01). CSIC reflects intratumor reticuloendothelial cellular functions, and is therefore useful in differentiating hepatocellular carcinoma from adenomatous hyperplasia without atypia.

Three-dimensional black blood MR angiography of the liver during breath holding: A comparison with two-dimensional time-of-flight MR angiography

In 2-D time-of-flight MR angiography (2-D TOF MRA) of the liver, artifacts caused by respiratory motion are unavoidable. Therefore, a 3-D black blood MRA of the liver was attempted in 7 healthy volunteers, using a 3-D gradient echo sequence which allows imaging during breath holding. 2-D TOF MRA was performed as well. In all subjects, 3-D MRA allowed visualization of the trunk, 1st-, and 2nd-order branches of the portal vein without interruption. Right 3rd-order branches were visualized without interruption in 6 of 7 subjects (85%). However, with 2-D MRA, the transverse portion of the left main portal vein could not be visualized in any subject, and the periphery of the portal vein was less clear than with 3-D MRA.

Three-dimensional black blood MR angiography of the liver during breath holding

In 2-D time-of-flight MR angiography (2-D TOF MRA) of the liver, artifacts caused by respiratory motion are unavoidable. Therefore, a 3-D black blood MRA of the liver was attempted in 7 healthy volunteers, using a 3-D gradient echo sequence which allows imaging during breath holding. 2-D TOF MRA was performed as well. In all subjects, 3-D MRA allowed visualization of the trunk, 1st-, and 2nd-order branches of the portal vein without interruption. Right 3rd-order branches were visualized without interruption in 6 of 7 subjects (85%). However, with 2-D MRA, the transverse portion of the left main portal vein could not be visualized in any subject, and the periphery of the portal vein was less clear than with 3-D MRA.

Safety and Risk of Superselective Transcatheter Arterial Embolization for Acute Lower Gastrointestinal Hemorrhage with N-Butyl Cyanoacrylate: Angiographic and Colonoscopic Evaluation

PURPOSE To retrospectively evaluate the safety and risk of transcatheter arterial embolization (TAE) with N-butyl cyanoacrylate (NBCA) for urgent acute arterial bleeding control in the lower gastrointestinal tract by angiography and colonoscopy. MATERIALS AND METHODS NBCA TAE was performed in 16 patients (mean age, 63.7 y) with lower gastrointestinal bleeding (diverticular hemorrhage, tumor bleeding, and intestinal tuberculosis). Angiographic evaluation was performed by counting the vasa recta filled with casts of NBCA and ethiodized oil (Lipiodol) after TAE. Patients were classified as follows: group Ia, with a single vas rectum with embolization of 1 branch (n = 6); group Ib, with a single vas rectum with embolization of ≥ 2 branches (n = 8); group II, with embolization of multiple vasa recta (n = 2). All patients underwent colonoscopy within 1 month, and ischemic complications (ulcer, scar, mucosal swelling, fibrinopurulent debris, and necrosis) were evaluated. RESULTS The procedure was successful in all patients. No ischemic change was observed in any patients in group Ia and in two patients in group Ib. Ischemic changes were observed in six group Ib patients and both group II patients. Group Ib patients experienced ischemic complications that improved without treatment. One patient in group II underwent resection for intestinal perforation after embolization of three vasa recta. One patient in group II with sigmoid stricture with embolization of six vasa recta required prolonged hospitalization. CONCLUSIONS NBCA embolization of ≥ 3 vasa recta can induce ischemic bowel damage requiring treatment. NBCA TAE of one vas rectum with ≥ 2 branches could also induce ischemic complications. However, these were silent and self-limited.

Successful closure of intractable tracheoesophageal fistula using a combination of a modified silicon stent and metallic stents.

Although surgery is the usual management strategy for acquired benign tracheoesophageal fistula, sometimes this approach is contraindicated or the patient declines surgical management. In this report, we describe a case of a patient with tracheoesophageal fistula at the level of the carina due to bronchial arterial infusion chemotherapy. Closure could not be achieved in response to multiple treatment strategies, including airway stenting, esophageal stenting, occlusion with microcoils, or cyanoacrylate glue. We subsequently achieved closure of this fistula through the combination of a modified silicon stent and metallic stents.

Double Contrast MR Imaging with Iron Colloid and Gd-DTPA in Cholangiocellular Carcinoma

Double contrast MR imaging with combined use of chondroitin sulfate iron colloid (CSIC) and Gd-DTPA was attempted in 3 cases of cholangiocellular carcinoma (CCC). In all cases, nonenhanced spin echo T1- and T2-weighted images, and T1-weighted images after i.v. injection of Gd-DTPA were obtained. Within one week, the MR sequences were repeated one hour after i.v. injection of CSIC. Double contrast (CSIC/Gd-DTPA) T1-weighted imaging was evaluated and compared with the other sequences in terms of tumor detectability, tumor spreading and tumor characterization. Double contrast MR imaging was comparable in tumor detectability and superior as to the evaluation of spreading and characterization to the other MR imaging modalities.

Coil Embolization with Side-Holed Catheter to Preserve Peripheral Flow for Visceral Artery Pseudoaneurysm: An Experimental Study in Swine

PURPOSE To evaluate the safety and efficacy of coil embolization with an indwelling catheter with side holes to control visceral artery bleeding while simultaneously preserving peripheral artery flow. MATERIALS AND METHODS A 6-F anticoagulant-coated catheter with two symmetrically arranged side holes was used with coil embolization to induce hemostasis in the superior mesenteric artery (SMA) of 13 pigs. The SMA was punctured with a metal needle to induce bleeding. The catheter was advanced into the SMA immediately after the puncture, and the midpoint between its tip and side holes was adjusted to conform to the puncture site. The SMA was embolized by using microcoils placed around the catheter to achieve hemostasis. Hemostasis and gross ischemic changes of the intestine were visually observed during the abdominal surgery. Peripheral blood flow was assessed by using abdominal aortography for as long as 2 hours in 13 pigs and was assessed again at 7 days in three pigs. RESULTS Antegrade peripheral artery flow through the indwelling catheter was preserved without stagnation for as long as 2 hours in all 13 pigs and at 7 days in two of three pigs. One catheter occlusion was seen at the 7-day time point. There were no observable instances of recurrent bleeding, ischemic changes in the intestine, or vascular adverse events during or after the procedure. CONCLUSIONS The hemostatic method described here is a technically feasible method of controlling acute visceral artery bleeding while preserving peripheral artery flow and may be particularly useful in cases of absence of collateral circulation. Further experiments are warranted for clinical application.

A preliminary report on three-dimensional magnetic resonance angiography of the liver with bolus injection of Gd-DTPA

Abstract For nine healthy volunteers, we attempted to apply three-dimensional magnetic resonance angiography (3D-MRA) of the liver, using the 3D-gradient echo sequences which allow image during one breath-holding after intravenous bolus injection of gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). When the portal venous segment of interest was visualized with no discontinuation, the result was assessed as positive. The rate of positive imaging was examined for each branch of the portal venous system. With the exception of the horizontal segment of the left portal branch, the main trunk, the first- and second-order branches of the portal system were all visualized without interruption. For the third-order branches, greater than 80% of right branches were positive but the rate was less than 40% for the left. Since this technique allows the portal system to be visualized uninterruptedly for a short time with one breath-holding, it is promising as a new method of abdominal MRA.