Hwan Jun Jae

Acute iliofemoral deep vein thrombosis: evaluation of underlying anatomic abnormalities by spiral CT venography.

PURPOSE To evaluate the spectrum of underlying anatomic abnormalities in iliofemoral deep vein thrombosis (DVT) by spiral computed tomographic (CT) venography. MATERIALS AND METHODS During the past 4 years, 56 patients with acute iliofemoral DVT have been evaluated by CT venography at our institution. Forty-four patients had left-sided DVT, nine had right-sided DVT, and the remaining three had DVT in both extremities. CT venography was performed with use of 2.5-3.2-mm x-ray beam collimation and a 1.25-2.0-mm reconstruction interval. Spiral scans were initiated 5 minutes after intravenous contrast medium injection. The CT venograms were correlated with catheter venograms. In addition, with use of axial sections and their three-dimensional reconstructions, including multiplanar reformation and volume rendering, the presence or absence of central obstructing lesions and their causes were evaluated. RESULTS Among 44 patients with left-sided DVT, 37 had significant anatomic abnormalities in their iliofemoral veins or inferior vena cava (IVC). The most common lesion was left common iliac vein compression by the right common iliac artery (n = 27; exaggerated by a bony spur in nine and associated with extrinsic compression by the left internal iliac artery in two). Of the nine patients with right-sided DVT, six had significant anatomic abnormalities including encasement or extrinsic compression of their iliac veins by various causes (n = 3) and venous stricture without extrinsic lesions (n = 3). Among three patients with DVT in both extremities, two had anatomic abnormalities in the IVC. Therefore, 45 of 56 patients had anatomic abnormalities central to the thrombosed deep veins. CONCLUSION The majority of patients with acute iliofemoral DVT had underlying anatomic abnormalities. The presence of central stenosis or obstruction and their causes can be evaluated by spiral CT venography.

Celiac Axis and Common Hepatic Artery Variations in 5002 Patients: Systematic Analysis with Spiral CT and DSA

PURPOSE To identify and evaluate the spectrum and prevalence of celiac axis (CA) and common hepatic artery (CHA) variations by using spiral computed tomography (CT) and digital subtraction angiography (DSA). MATERIALS AND METHODS Institutional review board approval was obtained, and the requirement for informed patient consent was waived. The findings in 5002 patients who underwent spiral CT and DSA were retrospectively evaluated. CHA was defined as an arterial trunk containing at least one segmental hepatic artery and the gastroduodenal artery. The pattern of the aortic origin of the branches of the CA and superior mesenteric arteries was analyzed. The CHA anatomy was then investigated. RESULTS Of 15 possible types of CA variation, 13 types were identified. A normal CA was noted in 4457 (89.1%) of the 5002 patients. Twelve types of CA variation were identified in 482 (9.64%) patients. In the remaining 63 (1.26%) patients, the CA anatomy was classified as ambiguous because the CHA was absent owing to separate origins of the hepatic arteries and the gastroduodenal artery (n = 55) or because the origin of the CHA could not be determined owing to persistent anastomotic channels (n = 8). Seven CHAs originating from the normal CA had a retroportal (n = 6) or transpancreatic (n = 1) course. All eight CHAs originating from the left gastric artery passed the fissure of the ligamentum venosum. The 148 CHAs originating from the superior mesenteric artery showed diverse relationships with the pancreas--being supra-, trans-, or infrapancreatic--and the superior mesenteric-portal venous axis--being pre- or retroportal. The 20 CHAs originating from the aorta had a normal suprapancreatic preportal course. CONCLUSION Known or newly found CA and CHA variations could be systematically described in detail. The authors propose a hypothetical anatomic model for summarizing the observed CHA variations.

Effects of Nitroglycerin on the Diagnostic Accuracy of Electrocardiogram-gated Coronary Computed Tomography Angiography

Objectives: To evaluate the effect of nitroglycerin on the diagnostic accuracy of electrocardiogram-gated coronary computed tomography (CT) angiography in patients with suspected coronary artery disease. Methods: Computed tomography angiography was performed on 76 patients using a 16-slice CT scanner. Forty-six patients received a sublingual nitroglycerin 1 minute before CT scanning (the NTG group), but the other 30 did not (the non-NTG group). No statistically significant differences were evident between these 2 groups in terms of clinical and demographic characteristics. Significant stenosis (≥50% diameter reduction) as determined by CT was evaluated according to patient-based and segment-based analyses, and results were compared with conventional coronary angiographic findings. In addition, segments of the coronary artery were reclassified by segment luminal size into proximal, mid, and distal segments, and the diagnostic accuracies of the NTG and non-NTG approaches were evaluated in these segments. Results: Differences in heart rate, and systolic and diastolic blood pressures before and after using nitroglycerin were 1.0 ± 2.4 beats per minute, −8.3 ± 14.4 mm Hg, and −4.6 ± 10.6 mm Hg, respectively. Sensitivity, specificity, and positive and negative predictive values in the NTG group were higher than in the non-NTG group by patient-based analysis (P = 0.25) and by segment-based analysis (P < 0.05). In addition, based on the luminal size of each segment, diagnostic accuracy in the NTG group was significantly higher for proximal segments than in the non-NTG group (96.7% vs 89.7%; P < 0.05). Conclusions: The use of nitroglycerin was found to be safe and to improve the diagnostic accuracy of coronary CT angiography for the evaluation of coronary artery disease.

Transcatheter Arterial Embolization of Nonvariceal Upper Gastrointestinal Bleeding with N-Butyl Cyanoacrylate

Objective To evaluate the clinical efficacy and safety of transcatheter arterial embolization (TAE) with N-Butyl Cyanoacrylate (NBCA) for nonvariceal upper gastrointestinal bleeding. Materials and Methods Between March 1999 and December 2002, TAE for nonvariceal upper gastrointestinal bleeding was performed in 93 patients. The endoscopic approach had failed or was discarded as an approach for control of bleeding in all study patients. Among the 93 patients NBCA was used as the primary embolic material for TAE in 32 patients (28 men, four women; mean age, 59.1 years). The indications for choosing NBCA as the embolic material were: inability to advance the microcatheter to the bleeding site and effective wedging of the microcatheter into the bleeding artery. TAE was performed using 1:1-1:3 mixtures of NBCA and iodized oil. The angiographic and clinical success rate, recurrent bleeding rate, procedure related complications and clinical outcomes were evaluated. Results The angiographic and clinical success rates were 100% and 91% (29/32), respectively. There were no serious ischemic complications. Recurrent bleeding occurred in three patients (9%) and they were managed with emergency surgery (n = 1) and with a successful second TAE (n = 2). Eighteen patients (56%) had a coagulopathy at the time of TAE and the clinical success rate in this group of patients was 83% (15/18). Conclusion TAE with NBCA is a highly effective and safe treatment modality for nonvariceal upper gastrointestinal bleeding, especially when it is not possible to advance the microcatheter to the bleeding site and when the patient has a coagulopathy.

Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Prevalence and Causative Factors of Extrahepatic Collateral Arteries in 479 Patients

Objective We wanted to investigate the prevalence and causative factors of extrahepatic arterial blood supply to hepatocellular carcinoma (HCC) at its initial presentation and during chemoembolization. Materials and Methods Between February 1998 and April 2000, consecutive 479 patients with newly diagnosed HCC were prospectively enrolled into this study. A total of 1629 sessions of transcatheter arterial chemoembolization (TACE) were performed in these patients (range: 1-15 sessions; mean: 3.4 sessions) until April 2004. For each TACE procedure, we determined the potential extrahepatic collateral arteries (ExCAs) depending on the location of the tumor, and we performed selective angiography of all suspected collaterals that could supply the tumor. The prevalence of ExCAs and the causative factors were analyzed. Results At initial presentation, 82 (17%) of these 479 patients showed 108 ExCAs supplying tumors. Univariate analysis showed that tumor size (p < 0.01), patient age (p = 0.02), a surface location (p < 0.01), and a bare area location (p < 0.01) were significantly associated with the presence of ExCAs. Multiple logistic regression analysis showed that only tumor size was predictive of ExCA formation (p < 0.01, odds ratio = 1.737, confidence interval: 1.533 to 1.969). During repeated TACE sessions, 97 additional ExCAs were detected in 70 (14%) patients. The cumulative probability of ExCAs in patients with a large tumor (≥ 5 cm) was significantly higher than that for those patients with a small tumor (< 5 cm) (p < 0.01). Conclusion The presence of ExCAs supplying HCC is rather common, and the tumor size is a significant causative factor for the development of these collateral arteries.

The Role of Perfusion CT as a Follow-up Modality After Transcatheter Arterial Chemoembolization An Experimental Study in a Rabbit Model

Objectives:To prospectively evaluate the feasibility of perfusion CT as a follow-up modality after transcatheter arterial chemoembolization (TACE) and to compare these findings with those of histopathology as the reference standard in a VX2 tumor rabbit model. Materials and Methods:VX2 carcinoma tumors were implanted into the liver of 20 rabbits 3 weeks prior to TACE. Perfusion CT was performed prior to TACE and 1- and 4-week after TACE. After obtaining perfusion index maps on perfusion CT, 2 radiologists measured the parametric perfusion indices of blood flow (BF), blood volume (BV), mean transit time (MTT), permeability of the capillary vessel surface (PS), and hepatic arterial fraction (HAF) of primary tumors on pre-TACE perfusion CT, chemoembolized primary tumors on 1-week perfusion CT, and recurred tumors on 4-week perfusion CT. The normal liver parenchyma indices were also recorded. In addition, the radiologists investigated the presence of a recurred tumor adjacent to the chemoembolized area on perfusion index maps of 4-week CT images. The areas of higher hepatic blood flow (HBF), hepatic blood volume (HBV), PS, and HAF, and lower MTT on 4-week perfusion CT than the normal liver parenchyma and the identical area on 1-week perfusion CT were considered as recurred tumors. Histopathology revealed the presence of a recurred tumor, and mean vessel density (MVD) was determined by immunochemical staining for CD31. CT perfusion indices were compared by use of the t test. Comparisons were made for the primary tumor versus normal liver parenchyma on pre-TACE CT, the primary tumor on pre-TACE CT versus the chemoembolized tumor on 1-week CT, the recurred tumor on 4-week CT versus the identical area on 1-week CT, and the primary tumor on pre-TACE CT versus the recurred tumor on 4-week CT. For the detection of recurred tumors, the sensitivity and specificity for 4-week perfusion CT were calculated. Correlation analysis between the recurred tumor perfusion indices and the MVD of the corresponding tumor region was performed. Among 20 rabbits, 6 were excluded from the analysis, and results were based on 14 rabbits. Results:Recurred tumors were histologically proven in 8 of 14 rabbits (57.1%). The BF, BV, PS, and HAF indices of primary tumors were significantly higher, whereas the MTT was significantly lower than that of the normal liver parenchyma on pre-TACE perfusion CT and that of chemoembolized areas on 1-week perfusion CT (P < 0.05). In addition, recurred tumors also showed significantly higher BF, BV, PS, and HAF, and lower MTT indices than the identical areas on 1-week perfusion CT (P < 0.05). The perfusion indices of recurred tumors were not significantly different from the indices of primary tumors (P > 0.05). Both sensitivity and specificity were 100% for 4-week perfusion CT. There were significant positive correlations between BF (r = 0.947), BV (r = 0.758), PS (r = 0.759), HAF (r = 0.955), and MVD in recurred tumors, and a significant inverse correlation between MTT (r = −0.782) and MVD was observed (P < 0.05). Conclusions:We believe that perfusion CT is a feasible alternative modality for the successful early response assessment and early detection of a marginally recurred tumor after TACE. However, perfusion CT has limitations for the prediction of tumor recurrence after TACE.

Unusual Causes of Varicose Veins in the Lower Extremities: CT Venographic and Doppler US Findings

There are various causes of varicose veins in the lower extremities. Among the causes are venous insufficiency of the saphenofemoral junction, saphenopopliteal junction, or usual perforating veins. Traditionally, Doppler ultrasonography (US) has been used for evaluation of varicose veins. Sometimes, varicose veins arise from an unexpected anatomic source; in these cases, computed tomographic (CT) venography can provide an overview of the varicose veins. Doppler US with complementary CT venography is useful for determining the precise cause of varicose veins. Between November 2003 and March 2008, the authors evaluated 1350 cases of varicose veins in the lower extremities with both CT venography and Doppler US. The varicose veins were classified according to their causes; unusual causes were studied and included vulvoperineal varicosity, intraosseous perforating vein incompetence, round ligament varicosity, persistent sciatic vein incompetence, Klippel-Trenaunay syndrome, and portosystemic collateral pathways. Radiologists should be familiar with the complete range of primary causes of varicose veins in the lower extremities and with their radiologic manifestations and should recognize the complementary role of CT venography in their evaluation.

May-Thurner Syndrome Complicated by Acute Iliofemoral Vein Thrombosis: Helical CT Venography for Evaluation of Long-Term Stent Patency and Changes in the Iliac Vein

OBJECTIVE The purpose of this study was to use CT venography to evaluate long-term patency and changes in the iliac veins after stent placement for acute iliofemoral vein thrombosis due to May-Thurner syndrome. MATERIALS AND METHODS From December 1999 to July 2007, 30 patients (22 women, eight men; age range, 30-78 years; mean, 56.7 years) with acute iliofemoral vein thrombosis due to May-Thurner syndrome diagnosed with CT venography were treated with catheter-directed thrombolysis and stent placement. The patients underwent follow-up CT venography at variable intervals according to clinician discretion. The primary objective was to determine the primary patency of the stented segment. The secondary objective was to investigate the potential role of CT venography by analyzing the morphologic features and interval changes in stented iliac veins. Cumulative primary and secondary stent patency rates were calculated by Kaplan-Meier estimation. RESULTS Four stent occlusions and one stent collapse were found at the first follow-up CT venographic examination within 1 year (mean duration, 129.3 days) after treatment. One stent occlusion and one stent collapse were managed successfully. The primary and secondary patency rates were 83.3% and 90% 1 and 5 years after treatment. The morphologic features of the common iliac vein did not affect stent patency or expanded stent diameter. During sequential CT venographic follow-up, no new in-stent stenosis or occlusion was found. CONCLUSION Iliac stents placed for May-Thurner syndrome with acute thrombosis had excellent long-term patency. Restenosis or occlusion occurred early, and initial luminal patency was well maintained during long-term follow-up.

Ultrasound-mediated gene and drug delivery using a microbubble-liposome particle system.

Theranostic agents present a promising clinical approach for cancer detection and treatment. We herein introduce a microbubble and liposome complex (MB-Lipo) developed for ultrasound (US) imaging and activation. The MB-Lipo particles have a hybrid structure consisting of a MB complexed with multiple Lipos. The MB components are used to generate high echo signals in US imaging, while the Lipos serve as a versatile carrier of therapeutic materials. MB-Lipo allows high contrast US imaging of tumor sites. More importantly, the application of high acoustic pressure bursts MBs, which releases therapeutic Lipos and further enhances their intracellular delivery through sonoporation effect. Both imaging and drug release could thus be achieved by a single US modality, enabling in situ treatment guided by real-time imaging. The MB-Lipo system was applied to specifically deliver anti-cancer drug and genes to tumor cells, which showed enhanced therapeutic effect. We also demonstrate the clinical potential of MB-Lipo by imaging and treating tumor in vivo.

Safety and Efficacy of Transcatheter Arterial Embolization for Lower Gastrointestinal Bleeding: A Single-center Experience with 112 Patients

PURPOSE To assess the safety and efficacy of transcatheter arterial embolization for lower gastrointestinal bleeding (LGIB) and to determine the prognostic factors that affect clinical outcome. MATERIALS AND METHODS All patients diagnosed with LGIB by angiography at a single institution from April 2006 to January 2013 were included in a retrospective study. The rates of technical success, early recurrent bleeding, major complications, clinical success, and in-hospital mortality for transcatheter arterial embolization were determined. The influence of possible prognostic factors on the outcome was analyzed. RESULTS A total of 112 patients were included (36 with small-bowel LGIB, 36 with colon LGIB, and 40 with rectal LGIB). N-butyl cyanoacrylate (NBCA) was the embolic agent for 84 patients (75.0%), whereas gelatin sponge pledgets (n = 20), microcoils (n = 2), polyvinyl alcohol particles with adjunctive gelatin sponge pledgets (n = 1), and blood clots (n = 1) were used in the other patients. The technical success rate was 96.4%. For the entire group, the rates of early recurrent bleeding, major complications, clinical success, and in-hospital mortality were 17.4%, 4.6%, 74.5%, and 25.0%, respectively. These were 15.2%, 4.8%, 75.3%, and 26.2%, respectively, in the NBCA group. Hematologic malignancy, immobilization status, and coagulopathy were significant prognostic factors for clinical outcomes. CONCLUSIONS Transcatheter arterial embolization is a safe and effective treatment for LGIB. NBCA could be used as a primary embolic agent for this procedure.