Yong Hu Yin

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.

The Image Quality and Radiation Dose of 100-kVp versus 120-kVp ECG-Gated 16-Slice CT Coronary Angiography

Objective This study was conducted to assess the feasibility of performing 100-kVp electrocardiogram (ECG)-gated coronary CT angiography, as compared to 120-kVp ECG-gated coronary CT angiography. Materials and Methods We retrospectively evaluated one hundred eighty five gender- and body mass index-matched 16-slice coronary CT sets of data, which were obtained using either 100 kVp and 620 effective mAs or 120 kVp and 500 effective mAs. The density measurements (image noise, vessel density, signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) and the estimated radiation dose were calculated. As a preference test, two image readers were independently asked to choose one image from each pair of images. The results of both protocols were compared using the paired t-test or the Wilcoxon signed rank test. Results The 100-kVp images showed significantly more noise and a significantly higher vessel density than did the 120-kVp images. There were no significant differences in the SNR and CNR. The estimated reduction of the radiation dose for the 100-kVp protocol was 24%; 7.8 ± 0.4 mSV for 100-kVp and 10.1 ± 1.0 mSV for 120-kVp (p < 0.001). The readers preferred the 100-kVp images for reading (reader 1, p = 0.01; reader 2, p = 0.06), with their preferences being stronger when the subjects body mass index was less than 25. Conclusion Reducing the tube kilovoltage from 120 to 100 kVp allows a significant reduction of the radiation dose without a significant change in the SNR and the CNR.

Ultrasound and Fluoroscopy-Guided Placement of Central Venous Ports via Internal Jugular Vein: Retrospective Analysis of 1254 Port Implantations at a Single Center

Objective To assess the technical success and complication rates of the radiologic placement of central venous ports via the internal jugular vein. Materials and Methods We retrospectively reviewed 1254 central venous ports implanted at our institution between August 2002 and October 2009. All procedures were guided by using ultrasound and fluoroscopy. Catheter maintenance days, technical success rates, peri-procedural, as well as early and late complication rates were evaluated based on the interventional radiologic reports and patient medical records. Results A total of 433386 catheter maintenance days (mean, 350 days; range 0-1165 days) were recorded. The technical success rate was 99.9% and a total of 61 complications occurred (5%), resulting in a post-procedural complication rate of 0.129 of 1000 catheter days. Among them, peri-procedural complications within 24 hours occurred in five patients (0.4%). There were 56 post-procedural complications including 24 (1.9%, 0.055 of 1000 catheter days) early and 32 (2.6%, 0.074 of 1000 catheter days) late complications including, infection (0.6%, 0.018 of 10000 catheter days), thrombotic malfunction (1.4%, 0.040 of 1000 catheter days), nonthrombotic malfunction (0.9%, 0.025 of 1000 catheter days), venous thrombosis (0.5%, 0.014 of 1000 catheter days), as well as wound problems (1.1%, 0.032 of 1000 catheter days). Thirty six CVPs (3%) were removed due to complications. Bloodstream infections and venous thrombosis were the two main adverse events prolonging hospitalization (mean 13 days and 5 days, respectively). Conclusion Radiologic placement of a central venous port via the internal jugular vein is safe and efficient as evidenced by its high technical success rate and a very low complication rate.

Three-Dimensional CT Venography of Varicose Veins of the Lower Extremity: Image Quality and Comparison with Doppler Sonography

OBJECTIVE The purpose of this study was to verify the imaging quality of CT venography in the clinical evaluation of the lower extremity superficial venous system and to correlate the CT and duplex sonographic findings about varicose veins. SUBJECTS AND METHODS One hundred consecutively registered patients with varicose veins underwent CT venography. The image quality of overall 3D volume rendering was rated, and the absolute attenuation of each component at the level of the knee was measured. Factors that affected visualization of varicose veins were identified. For comparison analysis, 50 of the 100 patients also underwent Doppler sonography, and saphenous vein size and morphologic features on CT were compared with the functional information from Doppler sonography. RESULTS The overall quality of 3D volume-rendered images in the visualization of varicose veins was excellent in 76% of patients, fair in 21%, and poor in 3%. The entire length of the great saphenous vein (GSV) was visualized with CT venography in 99.5% of 200 GSVs. The quality of 3D volume-rendered images was better when a thick subcutaneous layer, no skin changes, and no subcutaneous edema were present. Size of the GSV determined whether findings at CT venography and Doppler sonography correlated well, the linear regression coefficient being 0.72. At CT venography, the mean diameter of GSVs exhibiting insufficiency on duplex sonography was 7.0 mm, and the mean diameter of GSVs exhibiting competence on duplex sonography was 4.9 mm (p < 0.001). Prediction of GSV insufficiency with CT venography had a sensitivity of 98.2% and a specificity of 83.3%. CONCLUSION CT venography has adequate image quality for evaluation of the venous system of the lower extremities.

The Diagnostic Accuracy, Image Quality and Radiation Dose of 64-Slice Dual-Source CT in Daily Practice: a Single Institution's Experience

Objective We wanted to evaluate the image quality, diagnostic accuracy and radiation exposure of 64-slice dual-source CT (DSCT) coronary angiography according to the heart rate in symptomatic patients during daily clinical practice. Materials and Methods We performed a retrospective search for the DSCT coronary angiography reports of 729 consecutive symptomatic patients. For the 131 patients who underwent invasive coronary angiography, the image quality, the diagnostic performance (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] for detecting significant stenosis ≥ 50% diameter) and the radiation exposure were evaluated. These values were compared between the groups with differing heart rates (HR): mean HR < 65 or ≥ 65 and HR variability (HRV) < 15 or ≥ 15. Results Among the 729 patients, the CT reports showed no stenosis or insignificant coronary artery stenosis in 72%, significant stenosis in 26% and non-diagnostic in 2%. For the 131 patients who underwent invasive coronary angiography, 95% of the patients and 97% of the segments were evaluable, and the overall per-patient/per-segment sensitivity, the perpatient/per-segment specificity, the per-patient/per-segment PPV and the per-patient/per-segment NPV were 100%/90%, 71%/98%, 95%/88% and 100%/97%, respectively. The image quality was better in the HR < 65 group than in the HR ≥ 65 group (p = 0.001), but there was no difference in diagnostic performance between the two groups. The mean effective radiation doses were lower in the HR < 65 or HRV < 15 group (p < 0.0001): 5.5 versus 6.7 mSv for the mean HR groups and 5.3 versus 9.3 mSv for the HRV groups. Conclusion Dual-source CT coronary angiography is a highly accurate modality in the clinical setting. Better image quality and a significant radiation reduction are being rendered in the lower HR group.

Extrahepatic Collateral Artery Supply to the Tumor Thrombi of Hepatocellular Carcinoma Invading Inferior Vena Cava: The Prevalence and Determinant Factors

PURPOSE To retrospectively evaluate the prevalence of extrahepatic collateral artery supply to tumor thrombi of hepatocellular carcinomas (HCCs) invading the inferior vena cava (IVC) and to assess the determining factors. MATERIALS AND METHODS From February 1998 to June 2007, 82 patients with IVC tumor thrombi on computed tomography (CT) underwent angiographic evaluation of their extrahepatic collateral artery supply. Potential determining factors for extrahepatic collateral artery supply to the IVC tumor thrombi included sex, age, Child-Pugh class, history of chemoembolization, tumor factors (ie, size, number, and growth pattern), distance from primary tumor to IVC thrombi, portal vein invasion, and extent of IVC thrombi (ie, occupying more than half the IVC lumen on transverse CT image, completely filling and distending IVC lumen, or extending into the right atrium). Univariate analysis and multiple logistic regression analysis were performed. RESULTS Fifty-four of the 82 patients (65.9%) had extrahepatic collateral artery supply: 47 from the right inferior phrenic artery, four from the right adrenal artery, two from the right internal mammary artery, and one from the right renal artery. The presence of extrahepatic collateral artery supply to IVC tumor thrombi showed a significant relationship with a history of chemoembolization (P = .001, odds ratio [OR] = 22.4) and distension of IVC by tumor thrombi (P = .005, OR = 9.1). CONCLUSIONS IVC tumor thrombi of HCCs are frequently supplied by extrahepatic collateral arteries, the most common of which is the right inferior phrenic artery. The significant determining factors are a history of chemoembolization and the extent of IVC tumor thrombi.

Preoperative evaluation of lower extremity arteries for free fibula transfer using MDCT angiography.

We discuss the preoperative application of computed tomographic (CT) angiography to identify legs suitable for free fibular flaps. Methods: The condition of 118 consecutive patients was prospectively evaluated by means of CT angiography for planned free fibula flap reconstructions. We retrospectively investigated whether fibular free flap transfer was performed in candidate patients and whether the presence of postoperative foot ischemia had been followed. Results: Multidetector row CT angiography demonstrated a normal arterial anatomy in 82 patients, anatomical variants in 30 patients, and peripheral arterial occlusive disease in 6 patients. The radiologists selected 20 legs as major variants that cannot ensure lower extremity viability after flap harvest. Sixty-three patients underwent fibula free flap transfer. The surgeons followed our imaging diagnosis and selected healthy legs as candidates for fibular free transfer in all but 2 patients. No postoperative foot ischemia presented in any patient. Conclusions: Computed tomographic angiography is a reliable preoperative imaging technique for the selection of appropriate legs as candidates for fibular free transfer.

Optimal scan timing and intravenous route for contrast-enhanced computed tomography in patients after Fontan operation.

Purpose: To determine the optimal scan timing and adequate intravenous route for patients having undergone the Fontan operation. Materials and Methods: A total of 88 computed tomographic images in 49 consecutive patients who underwent the Fontan operation were retrospectively evaluated and divided into 7 groups: group 1, bolus-tracking method with either intravenous route (n = 20); group 2, 1-minute-delay scan with single antecubital route (n = 36); group 3, 1-minute-delay scan with both antecubital routes (n = 2); group 4, 1-minute-delay scan with foot vein route (n = 3); group 5, 1-minute-delay scan with simultaneous infusion via both antecubital and foot vein routes (n = 2); group 6, 3-minute-delay scan with single antecubital route (n = 22); and group 7, 3-minute-delay scan with foot vein route (n = 3). The presence of beam-hardening artifact, uniform enhancement, and optimal enhancement was evaluated at the right pulmonary artery (RPA), left pulmonary artery (LPA), and Fontan tract. Optimal enhancement was determined when evaluation of thrombus was possible. Standard deviation was measured at the RPA, LPA, and Fontan tract. Results: Beam-hardening artifacts of the RPA, LPA, and Fontan tract were frequently present in groups 1, 4, and 5. The success rate of uniform and optimal enhancement was highest (100%) in groups 6 and 7, followed by group 2 (75%). An SD of less than 30 Hounsfield unit for the pulmonary artery and Fontan tract was found in groups 3, 6, and 7. Conclusions: The optimal enhancement of the pulmonary arteries and Fontan tract can be achieved by a 3-minute-delay scan irrespective of the intravenous route location.Abbreviations: computed tomography-CT, standard deviation-SD, Hounsfield unit-HU

Transcatheter Arterial Embolization Therapy for a Massive Polycystic Liver in Autosomal Dominant Polycystic Kidney Disease Patients

Polycystic liver is the most common extra-renal manifestation associated with autosomal dominant polycystic kidney disease (ADPKD), comprising up to 80% of all features. Patients with polycystic liver often suffer from abdominal discomfort, dyspepsia, or dyspnea; however, there have been few ways to relieve their symptoms effectively and safely. Therefore, we tried transcatheter arterial embolization (TAE), which has been used in treating hepatocellular carcinoma. We enrolled four patients with ADPKD in Seoul National University Hospital, suffering from enlarged polycystic liver. We embolized the hepatic arteries supplying the dominant hepatic segments replaced by cysts using polyvinyl alcohol particles and micro-coils. The patients were evaluated 12 months after embolization for the change in both liver and cyst volumes. Among four patients, one patient was lost in follow up and 3 patients were included in the analysis. Both liver (33%; 10%) and cyst volume (47.7%; 11.4%) substantially decreased in two patients. Common adverse events were fever, epigastric pain, nausea, and vomiting. We suggest that TAE is effective and safe in treating symptomatic polycystic liver in selected ADPKD patients.

Three-dimensional evaluation of the anatomic variations of the femoral vein and popliteal vein in relation to the accompanying artery by using CT venography.

Objective We wanted to describe the three-dimensional (3D) anatomic variations of the femoral vein (FV) and popliteal vein (PV) in relation to the accompanying artery using CT venography. Materials and Methods We performed a retrospective review of 445 bilateral (890 limbs) lower limb CT venograms. After the 3D relationship between the FV and PV and accompanying artery was analyzed, the presence or absence of variation was determined and the observed variations were classified. In each patient, the extent and location of the variations and the location of the adductor hiatus were recorded to investigate the regional frequency of the variations. Results There were four distinct categories of variations: agenesis (3 limbs, 0.3%), multiplication (isolated in the FV: 190 limbs, 21%; isolated in the PV: 14 limbs, 2%; and in both the FV and PV: 51 limbs, 6%), anatomical course variation (75 limbs, 8%) and high union of the tibial veins (737 limbs, 83%). The course variations included medial malposition (60 limbs, 7%), anterior rotation (11 limbs, 1%) and posterior rotation (4 limbs, 0.4%). Mapping the individual variations revealed regional differences in the pattern and frequency of the variations. Conclusion CT venography helps to confirm a high incidence of variations in the lower limb venous anatomy and it also revealed various positional venous anomalies in relation to the respective artery.