Young-Min Han

Comparison of Gadobenate Dimeglumine-Enhanced Dynamic MRI and 16-MDCT for the Detection of Hepatocellular Carcinoma

OBJECTIVEnThe objective of our study was to compare the diagnostic performance of gadobenate dimeglumine-enhanced MRI with that of 16-MDCT for the detection of hepatocellular carcinoma using receiver operating characteristic (ROC) curve analysis.nnnMATERIALS AND METHODSnThirty-one patients with 53 hepatocellular carcinomas underwent gadobenate dimeglumine-enhanced dynamic MRI and multiphasic CT using 16-MDCT within a mean interval of 5 days (range, 3-9 days). The dynamic MRI examination was performed using 3D fat-saturated volumetric interpolated imaging and sensitivity encoding on a 1.5-T unit. Both dynamic MRI and multiphasic MDCT included dual arterial phase images. Three observers independently interpreted the CT and MR images in random order, separately, and without patient identifiers. The diagnostic accuracy of each technique was evaluated using the alternative-free response ROC method. The sensitivity and positive predictive values were also calculated.nnnRESULTSnThe sensitivities of gadobenate dimeglumine-enhanced MRI for all observers were significantly higher than those of MDCT for all the lesions and for lesions 1.0 cm or smaller (p < 0.05); however, for lesions larger than 1.0 cm, the sensitivities of the two imaging techniques were similar. The mean area under the ROC curve (A(z)) of gadobenate dimeglumine-enhanced MRI (0.87 +/- 0.03 [SD]) was higher than that of MDCT (0.83 +/- 0.04), but no significant difference was found between them (p = 0.31). The number of false-positive findings on dynamic MRI was slightly higher than on MDCT, but no significant difference in the positive predictive value between the two imaging techniques was detected (observer 1, p = 0.06; observer 2, p = 0.13; observer 3, p = 1.00).nnnCONCLUSIONnGadobenate dimeglumine-enhanced MRI has a higher sensitivity for small hepatocellular carcinomas (</= 1 cm) but a higher false-positive rate due to nonspecific enhancement of benign lesions, such as arterioportal shunt, leading to no significant difference of overall accuracy when compared with MDCT.

Stents in Common Iliac Vein Obstruction with Acute Ipsilateral Deep Venous Thrombosis: Early and Late Results

PURPOSEnTo evaluate, by imaging and clinical follow-up, the effectiveness and long-term results of stent placement in cases of common iliac vein obstruction associated with ipsilateral deep vein thrombosis (DVT).nnnMATERIALS AND METHODSnRetrospective analysis of 22 patients (13 women, nine men; median age, 58 years) with common iliac vein obstruction with ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis (1,000-2,000 U urokinase per kg body weight per hour; n = 19), aspiration thrombectomy (n = 21), or angioplasty (n = 14) followed by stent placement (n = 22) via an ipsilateral popliteal vein approach (right, n = 2; left, n = 20) under ultrasonographic (US) guidance. Patients were then followed by duplex US, and patency rates were determined by Kaplan-Meier survival analysis.nnnRESULTSnThe mean procedure time was 15 hours (range, 1-23 hours) and the mean urokinase dose was 1,980,000 U (range, 600,000-3,600,000 U) before the implantation of 27 stents. Three patients did not receive urokinase. The technical success rate was 96% (26 of 27 stents) and the clinical success rate was 95% (21 of 22 patients). The causes of common iliac vein obstruction were May-Thurner syndrome (n = 16), pelvic mass (n = 2), and unknown (n = 4). The early complications included upward stent migration in one patient and a spinal epidural hematoma in another. The late complication was partial stent obstruction, which was successfully treated by thrombolysis and angioplasty in one patient. Follow-up lasted 1-41 months (mean, 21.4 months). Overall, the 1-year and 2-year primary patency rates were both 95% and the 1-year and 2-year secondary patency rates were both 100%.nnnCONCLUSIONnDirected catheter thrombolysis and aspiration of DVT are relatively safe, and the use of stents improves patency results in cases of common iliac vein obstruction.

Comparison of gadoxetic acid-enhanced MRI and superparamagnetic iron oxide-enhanced MRI for the detection of hepatocellular carcinoma

AIMnTo compare the diagnostic accuracy and sensitivity of gadoxetic acid-enhanced MRI and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) for the detection of hepatocellular carcinoma (HCC).nnnMATERIALS AND METHODSnEighty-nine patients (118 HCCs) who underwent three-dimensional gadoxetic acid-enhanced MRI and SPIO-enhanced MRI with a mean interval of 4.7 days (range 3-7 days), were included in this study. Two observers reviewed the gadoxetic acid set (unenhanced, early dynamic, 10 and 20 min hepatocyte-phase images) and SPIO set [unenhanced and ferucarbotran-enhanced T1-, T2-turbo spin-echo (TSE), and T2* weighted imaging (WI)] in consensus. Diagnostic accuracy and sensitivity were evaluated using the alternative-free response receiver operator characteristic (ROC) method.nnnRESULTSnThe area under ROC curve (Az value) and sensitivity of the gadoxetic acid set (Az 0.964; sensitivity 90.7%) were significantly higher than those of the SPIO set (Az 0.830; sensitivity 84.7%; p<0.05). There were 14 and seven lesions that were verified only on the gadoxetic acid set and only on the SPIO set, respectively. Four HCCs were clearly revealed as hypointense only on gadoxetic acid-enhanced hepatocyte phase imaging, but were occult on other sequences, including the SPIO set.nnnCONCLUSIONnGadoxetic acid-enhanced MRI is better than SPIO-enhanced MRI for the detection of HCCs.

Detection of Small Hypervascular Hepatocellular Carcinomas in Cirrhotic Patients: Comparison of Superparamagnetic Iron Oxide-Enhanced MR Imaging with Dual-Phase Spiral CT

Objective To compare the performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging at 1.5T and dual-phase spiral computed tomography (CT) for the depiction of small hypervascular hepatocellular carcinomas (HCCs). Materials and Methods Forty-three patients with 70 small nodular HCCs (5-20 mm; mean, 13.7 mm) were examined. Diagnosis was based on the results of surgical biopsy in 22 patients and by the combined assessment of MR imaging, lipiodol CT, alpha feto-protein levels, and angiographic findings in 21. MR imaging consisted of respiratory-triggered turbo spin-echo T2-weighted imaging, T1-weighted fast low-angle shot, and T2*-weighted fast imaging with steady-state precession imaging before and after SPIO enhancement. CT imaging was performed with 5-mm collimation and 1:1.4 pitch, and began 30 and 65 secs after the injection of 150 mL of contrast medium at a rate of 3 mL/sec. Two blinded observers reviewed all images independently on a segment-by-segment basis. Diagnostic accuracy was evaluated using receiver operating characteristics (ROC) analysis. Results The mean areas (Az) under the ROC curves were 0.85 for SPIO-enhanced MR imaging and 0.79 for dual-phase spiral CT (p < .05). The mean sensitivity of SPIO-enhanced MR imaging was significantly higher than that of CT (p < .05), i.e. 70.6% for MR imaging and 58.1% for CT. MR imaging had higher false-positive rates than dual-phase spiral CT, but the difference was not statistically significant (3.7% vs 3.3%) (p > .05). Conclusion SPIO-enhanced MR imaging is more sensitive than dual-phase spiral CT for the depiction of small hypervascular hepatocellular carcinomas.

Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

Objective We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Materials and Methods Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50-80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2-81 weeks). Results Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. Conclusion The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates.

Flared polyurethane-covered self-expandable nitinol stent for malignant biliary obstruction

PURPOSEnTo determine the technical efficacy and safety of a flared polyurethane-covered self-expandable nitinol stent in the management of malignant biliary obstruction and to evaluate its clinical efficacy by estimating stent patency and patient survival rates.nnnMATERIALS AND METHODSnThirteen patients with common bile duct strictures (nonhilar) caused by malignant disease were treated by placement of 13 nitinol stents. The stents used include a flared section in the proximal portion (12 mm in diameter and 10 mm in length) and a section in the remnant portion that is fully covered with high-elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 50-80 mm. Patient survival and stent patency rates were calculated with use of Kaplan-Meier survival analysis. The follow-up bilirubin and serum amylase and lipase levels were calculated, and the differences in means were evaluated with use of a Wilcoxon signed-rank test. The average follow-up duration was 22.9 weeks (range, 8-56 weeks).nnnRESULTSnPlacement was successful in all cases. The 30-day mortality rate was 0%. The survival rates were 38% and 24% at 20 and 50 weeks, respectively. Seventy-seven percent of study patients had adequate palliative drainage during their the remainder of their lives. The stent patency rates were 71% and 48% at 20 and 50 weeks, respectively. Three patients (23%) presented with stent occlusion requiring repeat intervention. There were no procedure-related complications such as proximal or distal migration. No complications occurred other than stent occlusion. One patients stent was removed under endoscopic guidance 15 weeks after its insertion. Bilirubin levels had significantly decreased 1 week after stent insertion (P <.001).nnnCONCLUSIONnPreliminary results suggest that placement of a flared polyurethane-covered self-expandable nitinol stent is feasible and effective in achieving biliary drainage. The stents do not migrate, but there is tumor ingrowth into the flared portion of the stent. Treatment of a larger group of patients will be mandatory to validate these long-term results.

The Clinical Outcomes of Transcatheter Microcoil Embolization in Patients with Active Lower Gastrointestinal Bleeding in the Small Bowel

Objective To assess the clinical outcomes of the transcatheter microcoil embolization in patients with active lower gastrointestinal (LGI) bleeding in the small bowel, as well as to compare the mortality rates between the two groups based on the visualization or non-visualization of the bleeding focus determined by an angiography. Materials and Methods We retrospectively evaluated all of the consecutive patients who underwent an angiography for treatment of acute LGI bleeding between January 2003 and October 2007. In total, the study included 36 patients who underwent a colonoscopy and were diagnosed to have an active bleeding in the LGI tracts. Based on the visualization or non-visualization of the bleeding focus, determined by an angiography, the patients were classified into two groups. The clinical outcomes included technical success, clinical success (no rebleeding within 30 days), delayed rebleeding (> 30 days), as well as the major and minor complication rates. Results Of the 36 patients, 17 had angiography-proven bleeding that was distal to the marginal artery. The remaining 19 patients did not have a bleeding focus based on the angiography results. The technical and clinical success rates of performing transcatheter microcoil embolizations in patients with active bleeding were 100% and 88%, respectively (15 of 17). One patient died from continued LGI bleeding and one patient received surgery to treat the continued bleeding. There was no note made on the delayed bleeding or on the major or minor complications. Of the 19 patients without active bleeding, 16 (84%) did not have recurrent bleeding. One patient died due to continuous bleeding and multi-organ failure. Conclusion The superselective microcoil embolization can help successfully treat patients with active LGI bleeding in the small bowel, identified by the results of an angiography. The mortality rate is not significantly different between the patients of the visualization and non-visualization groups on angiography.

Malignant esophageal-tracheobronchial strictures: parallel placement of covered retrievable expandable nitinol stents.

Purpose: To assess the safety and clinical effectiveness of the parallel placement of covered retrievable expandable metallic stents in the palliative treatment of malignant esophageal and tracheobronchial strictures. Material and Methods: Under fluoroscopic guidance, parallel stents were placed in 12 symptomatic patients with both malignant esophageal and tracheobronchial strictures. Seven of these 12 patients also had an esophagorespiratory fistula (ERF) and one patient had an esophagocutaneous fistula. Technical success, clinical improvement, complications, and survival rates were evaluated. Results: A total of 28 esophageal and airway stents were successfully placed. The grade of dysphagia and dyspnea score significantly decreased after stent placement (P = 0.002 and 0.003, respectively). ERF and esophagocutaneous fistula were sealed off in all eight patients after esophageal stent placement; however, the esophagocutaneous fistula reopened 1 month later. Complications included stent migration or expectoration (n = 3), tracheal compression by the esophageal stent (n = 3), new fistula development due to covering membrane degradation of the esophageal stent (n = 1), and symptomatic sputum retention (n = 1). Stent removal was easily performed for two stents; one migrated stent and the other with covering membrane degradation. All 12 patients died within the mean survival period of 72.50 days (range 7–375 days). Conclusion: Parallel placement of covered retrievable expandable metallic stents is safe and effective for the palliative treatment of malignant esophageal and tracheobronchial strictures.

Polyurethane-Covered Self-expandable Nitinol Stent for Malignant Biliary Obstruction: Preliminary Results

Purpose: To evaluatenthe immediate and long-term results in ten patients with malignant biliarynobstruction using a polyurethane-covered, self-expandable nitinol stent.nMethods: A nitinol stent, fully covered withnhigh-elasticity polyurethane, with an unconstrained diameter of 10 mm and antotal length of 60–80 mm, was placed transhepatically under fluoroscopicnguidance in ten patients. The length of the biliary obstruction varied betweenn30–50 mm. The follow-up examination included a clinical assessment, serumnbilirubin measurement, and ultrasound examinations at one-month intervals innall patients. Results: Initial stent deploymentnwas successful in eight patients. Two patients experienced proximal migration,nwhich was solved by insertion of two, uncovered Wallstents. One patient had thenstent removed after two weeks because of severe nausea and vomiting. Onenpatient had delayed migration of the covered stent after 40 weeks. Thenfollow-up duration was 3–40 weeks (Mean: 16.9 weeks). Seven patients diedn(3–26 weeks) and three patients survived (24–40 weeks). Thenbilirubin measurements in all patients had significantly decreased one weeknafter stent insertion. The levels of amylase and lipase had did not increasenafter stent insertion. Conclusions: Anpolyurethane-covered, self-expandable nitinol stent can be used effectively andnsafely in the treatment of malignant biliary obstruction. The preliminarynresults are favorable, but there is a need for further large studies tondetermine both long-term survival and patency. n

Acute upper limb ischemia due to cardiac origin thromboembolism: the usefulness of percutaneous aspiration thromboembolectomy via a transbrachial approach.

Objective To evaluate the usefulness of percutaneous aspiration thromboembolectomy (PAT) via a transbrachial approach in patients with acute upper limb ischemia. Materials and Methods From July 2004 to March 2008, eleven patients with acute upper limb ischemia were enrolled in this study. They were initially treated with thrombolysis (n = 1), PAT (n = 6), or both (n = 4) via a femoral artery approach. However, all of the patients had residual thrombus in the brachial artery, which was subsequently managed by PAT via the transbrachial approach for removal of residual emboli. Results Successful re-canalization after PAT via a transbrachial approach was achieved in all patients. Two patients experienced early complications: one experienced a massive hematoma of the upper arm due to incomplete compression and was treated by stent deployment. The other patient experienced a re-occlusion of the brachial artery the day after the procedure due to excessive manual compression of the puncture site, but did not show recurrence of ischemic symptoms in the artery of the upper arm. Clinical success with complete resolution of ischemic symptoms was achieved in all patients. Conclusion PAT via a transbrachial approach is a safe and effective treatment for patients with acute upper limb ischemia.