Matt Chiung-Yu Chen

Single-dose time-resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: Compared with digital subtraction angiography

To prospectively study the diagnostic performance of hybrid single‐dose contrast‐enhanced MRA of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the reference standard.

Fluoroscopic Guidance of Retrograde Exchange of Ureteral Stents in Women

OBJECTIVE The purpose of this study was to review our experience with fluoroscopically guided retrograde exchange of ureteral stents in women. MATERIALS AND METHODS During a 48-month period, 28 women (age range, 38-76 years) were referred to our department for retrograde exchange of a ureteral stent. The causes of urinary obstruction were tumor compression in 26 patients and benign fibrotic stricture in two patients. A large-diameter snare catheter (25-mm single loop or 18- to 35-mm triple loop) or a foreign body retrieval forceps (opening width, 11.3 mm) was used to grasp the bladder end of the stent under fluoroscopic guidance. The technique entailed replacement of a patent or occluded ureteral stent with a 0.035- or 0.018-inch guidewire with or without the aid of advancement of an angiographic sheath. RESULTS A total of 54 ureteral stents were exchanged with a snare catheter in 42 cases or a forceps in 12 cases. One stent misplaced too far up the ureter was replaced successfully through antegrade percutaneous nephrostomy. Ten occluded stents, including one single-J stent, were managed with a 0.018-inch guidewire in three cases, advancement of an angiographic sheath over the occluded stent into the ureter in five cases, and recannulation of the ureteral orifice with a guidewire in two cases. No complications of massive hemorrhage, ureter perforation, or infection were encountered. CONCLUSION With proper selection of a snare or forceps catheter, retrograde exchange of ureteral stents in women can be easily performed under fluoroscopic guidance with high technical success and a low complication rate.

The usefulness of fast-spin-echo T2-weighted MR imaging in Nutcracker syndrome: a case report.

Nutcracker syndrome occurs when the left renal vein (LRV) is compressed between the superior mesenteric artery and the aorta, and this syndrome is often characterized by venous hypertension and related pathologies. However, invasive studies such as phlebography and measuring the reno-caval pressure gradient should be performed to identify venous hypertension. Here we present a case of Nutcracker syndrome where the LRV and intra-renal varicosities appeared homogeneously hyperintense on magnetic resonance (MR) fast-spin-echo T2-weighted imaging, which suggested markedly stagnant intravenous blood flow and the presence of venous hypertension. The patient was diagnosed and treated without obtaining the reno-caval pressure gradient. The discomfort of the patient lessened after treatment. Furthermore, on follow-up evaluation, the LRV displayed a signal void, and this was suggestive of a restoration of the normal LRV flow and a decrease in LRV pressure.

Antegrade Retrieval of Ureteral Stents Through an 8-French Percutaneous Nephrostomy Route

OBJECTIVE The purpose of this study was to describe the technique of antegrade retrieval of ureteral stents under fluoroscopic guidance through an 8-French nephrostomy. MATERIALS AND METHODS During an 8-year period, we retrieved 26 ureteral stents from 24 patients who were not candidates for retrograde removal or had other conditions precluding use of a retrograde approach. A loop snare or grasping forceps was used to retrieve a ureteral stent in the renal pelvis or calyx or upper ureter through an 8-French vascular sheath with a safety wire in place. A snare catheter advanced into the bladder for retrieval of the bladder end was used in patients in whom retrieval with both a loop snare and a grasping forceps failed. RESULTS All 26 ureteral stents were successfully retrieved by the antegrade approach. Ten stents were retrieved with a snare alone and nine with a forceps alone. Five stents were retrieved successfully with a forceps after initial failures with snare catheters. Two stents were retrieved with snare catheters advanced into the bladder. The major complication of nephrostomy wound infection occurred in a patient with a urinary tract infection who underwent a one-stage procedure. All minor complications, including pelvic perforation in one patient and blood clot in the renal pelvis in four patients, resolved spontaneously without adverse sequelae. CONCLUSION Antegrade percutaneous retrieval of a ureteral stent through an 8-French nephrostomy is safe and effective and has a high degree of technical success. It can be used as a routine interventional practice in radiology.

Pharmaco-induced vasospasm therapy for acute lower gastrointestinal bleeding: A preliminary report

PURPOSE To report a novel technique and preliminary clinical outcomes in managing lower gastrointestinal bleeding (LGIB). MATERIALS AND METHODS Eighteen LGIB patients (11 men and 7 women, mean age: 66.2 years) were treated with artificially induced vasospasm therapy by semi-selective catheterization technique. Epinephrine bolus injection was used to initiate the vascular spasm, and followed by a small dose vasopressin infusion (3-5 units/h) for 3h. The technical success, clinical success, recurrent bleeding and major complications of this study were evaluated and reported. RESULTS Sixteen bleeders were in the superior mesenteric artery and 2 in the inferior mesenteric artery. All patients achieved successful immediate hemostasis. Early recurrent bleeding (<30 days) was found in 4 patients with local and new-foci re-bleeding in 2 (11.1%) each. Repeated vasospasm therapy was given to 3 patients, with clinical success in 2. Technical success for the 21 bleeding episodes was 100%. Lesion-based and patient-based primary and overall clinical successes were achieved in 89.4% (17/19) and 77.7% (14/18), and 94.7% (18/19) and 88.8% (16/18), respectively. None of our patients had complications of bowel ischemia or other major procedure-related complications. The one year survival of our patients was 72.2 ± 10.6%. CONCLUSIONS Pharmaco-induced vasospasm therapy seems to be a safe and effective method to treat LGIB from our small patient-cohort study. Further evaluation with large series study is warranted. Considering the advanced age and complex medical problems of these patients, this treatment may be considered as an alternative approach for interventional radiologists in management of LGIB.

Short-term follow-up for percutaneous extra-anatomic intervascular anastomosis in salvage of a thrombosed native arteriovenous fistula.

Percutaneous extra-anatomic intervascular anastomosis (PEIA), i.e., the nonsurgical connection of two anatomically unrelated vascular lumina, has rarely been reported in peripheral applications. Chen et al. [1] recently described a PEIA technique applied in peripheral vascular intervention. Using the same technique, the authors successfully salvaged an occluded native arteriovenous (AV) fistula with obliterated outflow veins. The vascular access has been followed up for more than 6 months and access-related complications are reported here. A 54-year-old woman with a failed and diffusely thrombosed native radiocephalic fistula in the right forearm was referred for shunt salvage. The fistula had been used for about 13 years. Informed consent was obtained. The institutional review board was not required for this retrospective report in our hospital. On physical examination, a hard and dilated forearm cephalic vein was noted, terminating as a venous stump not far below the elbow crease. Using local anesthesia, a 7-Fr introducer sheath was inserted in antegrade fashion in the forearm cephalic vein about 4 cm downstream of the AV anastomosis. A 4.1-Fr angiographic catheter was advanced to the venous stump and a small test bolus of contrast material was injected. No outflow vein from the venous stump could be identified on fluoroscopy. Under sonographic guidance, small thrombosed veins were catheterized, but attempts to get access into the dilated venous stump failed (Fig. 1A). During the search for small thrombosed veins around the venous stump, an upper arm basilic vein near and medial to the venous stump was noted. The patent basilic vein was catheterized under sonographic guidance and the venogram revealed no direct anastomosis with the venous stump (Fig. 1B) and the finding was comfirmed by sonography. A new vascular access creation was therefore suggested but the patient refused surgery after a thorough explanation to her and her family. In order to restore sufficient shunt flow, a good outflow drainage tract from the venous stump was required. Therefore, we attempted to salvage the fistula using the technique reported by Chen et al. [1] by stent-graft insertion between the venous stump and an adjacent patent basilic vein. An 8 · 60-mm stent-graft (Wallgraft; Boston Scientific, Natick, MA) was used to bridge the two ends of the fistulous tract. The stent-graft was dilated with an 8mm ·4-cm PTA balloon catheter. Thrombolysis was performed thereafter using 500,000 IU of urokinase. Thromboaspiration was performed with an 8-Fr Desilets-Hoffman sheath (Cook, Bloomington, IN, USA). Before thrombolysis, a bolus of 5000 IU heparin was given through a peripheral intravenous line. The AV fistula was successfully salvaged and the immediate follow-up fistulography showed brisk flow with presumed compression of a segment of the runoff basilic vein by hematoma (Fig. 1C; arrow). No immediate complications were noted and the patient underwent successful hemodialysis the next morning. The patient was called back for a fistulography 1 month after M. C.-Y. Chen (&) R.-H. Wu W.-S. Tzeng S.-C. Chang Department of Diagnostic Radiology, Chi-Mei Medical Center, Yung-Kang Campus, No. 901, Chung Hwa Road, Yung-Kang City, Tainan County 806, Taiwan e-mail: jjychen@gmail.com

The use of a Colapinto TIPS Needle under cone-beam computed tomography guidance for true lumen re-entry in subintimal recanalization of chronic iliac artery occlusion

Background To report the technique and clinical outcome of subintimal re‐entry in chronic iliac artery occlusion by using a Colapinto transjugular intrahepatic portosystemic shunt (TIPS) needle under rotational angiography (cone‐beam computed tomography; CT) imaging guidance. Methods Patients with chronic iliac artery occlusion with earlier failed attempts at conventional percutaneous recanalization during the past 5 years were enrolled in our study. In these patients, an ipsilateral femoral access route was routinely utilized in a retrograde fashion. A Colapinto TIPS Needle was used to aid the true lumen re‐entry after failed conventional intraluminal or subintimal guidewire and catheter‐based techniques. The puncture was directed under rotational angiography cone‐beam CT guidance to re‐enter the abdominal aorta. Bare metallic stents 8–10 mm in diameter were deployed in the common iliac artery, and followed by balloon dilation. Results Ten patients (9 male; median age, 75 years) were included in our investigation. The average occlusion length was 10.2 cm (range, 4–15 cm). According to the Trans‐Atlantic Inter‐Society Consensus (TASC) II classification, there were five patients each with Class B and D lesions. Successful re‐entry was achieved in all patients without procedure‐related complications. The ankle–brachial index (ABI) values increased from 0.38–0.79 to 0.75–1.28 after the procedure. Imaging follow‐up (> 6 months) was available in six patients with patency of all stented iliac artery. Thereafter, no complaints of recurrent clinical symptoms occurred during the follow‐up period. Conclusion The use of Colapinto TIPS needle, especially under cone‐beam CT image guidance, appears to be safe and effective to re‐enter the true lumen in a subintimal angioplasty for a difficult chronic total iliac occlusion.

TIPS in Patients With Cranial Porta Hepatis: Ultrasound-Guided Transhepatic Portohepatic-Portocaval Puncture in Single Needle Pass

OBJECTIVE The purpose of this study was to describe our technique of transhepatic serial puncture of the portal vein and hepatic vein-inferior vena cava in one needle pass under ultrasound guidance to place a transjugular intrahepatic portosystemic shunt (TIPS) in patients with a porta hepatis cranial to the usual location. MATERIALS AND METHODS Six patients (five men, one woman) underwent transhepatic TIPS procedures at our institution. The indications for portal decompression were recurrent variceal bleeding in four patients and refractory ascites and hydrothorax in one patient each. In five patients initial attempts at a classic transjugular approach failed because of an unusual angle between the hepatic vein and the portal vein; in the other patient, revision of an occluded shunt had failed. Two patients had main portal vein thrombosis. RESULTS Technical success was achieved in all six patients. Two patients received a portohepatic venous shunt and four a portocaval shunt (inferior vena cava to right portal vein in three patients and inferior vena cava to left portal vein in one patient).The portosystemic pressure gradient before TIPS was 17-35 mm Hg and after TIPS was 6-10 mm Hg. No procedure-related complications occurred. One patient had severe hepatic encephalopathy. Two patients had shunt occlusion, which was successfully revised 17 and 10 months after the procedure. CONCLUSION Our technique is a safe, effective, and universally applicable method for establishment of a TIPS in patients with either normal venous anatomy or severely distorted liver parenchyma.

Use of a portal vein localization sheath in the single-needle pass technique for creation of a portosystemic shunt

This study aimed to report a modification to the single-needle pass technique by use of a portal vein localization sheath for creation of a portosystemic shunt. The modification makes the single-needle pass technique a more straightforward procedure.

Treatment of Hemodialysis Vascular Access Rupture Irresponsive to Prolonged Balloon Tamponade: Retrospective Evaluation of the Effectiveness of N-Butyl Cyanoacrylate Seal-Off Technique

Objective The current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses. Materials and Methods We reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method. Results Twenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively. Conclusion Our results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.