Sectional Localization of a Small Hepatocellular Carcinoma in the Right Hepatic Lobe by Computed Tomography: Comparison between the Conventional and Portal Vein Tracing Methods.

PURPOSE: To compare the accuracy of the conventional and portal vein tracing methods in the right hepatic lobe in multidetector computed tomography (MDCT). MATERIALS AND METHODS: This retrospective study included patients with hepatocellular carcinoma (HCC) lesions in the right hepatic lobe who underwent multiphasic MDCT and C-arm CT hepatic arteriography (C-arm CTHA) for chemoembolization. The accuracies of the conventional and portal vein tracing methods were evaluated using C-arm CTHA as the gold standard. RESULTS: A total of 147 patients with 205 HCC nodules were included. The C-arm CTHA could identify all the tumour-feeding arteries and consequently demonstrated that 120 lesions were located in the anterior section, 78 in the posterior section, and 7 in the border zone. The accuracy rates of conventional vs. portal vein tracing methods were 71.7 % vs. 98.3 % for the anterior section lesions, 67.9 % vs. 96.2 % for the posterior section, and 28.6 % vs. 57.1 % for the border zone. The portal vein tracing method was more accurate than the conventional method (P<0.001). CONCLUSIONS: The portal vein tracing method should be used for sectional localization of HCCs in the right lobe, because it predicts the location more accurately than the conventional method. KEY POINTS: • Portal tracing method is more accurate than conventional method for tumour localization. • The conventional method is especially inaccurate in right anteroinferior or posterosuperior quadrants. • Scissurae between right anterior and posterior section may not be vertical but tilted.

Cone-beam CT hepatic arteriography in chemoembolization for hepatocellular carcinoma: angiographic image quality and its determining factors.

PURPOSE: To analyze image quality and the factors that determine it for cone-beam computed tomography (CT) hepatic arteriography in chemoembolization for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: From September 2009-December 2010, 399 consecutive patients referred for chemoembolization of HCC were scheduled for cone-beam CT scan. There were 12 patients (3%) excluded because of difficulty with breath-hold. Of the 387 patients who underwent cone-beam CT hepatic arteriography, 100 patients were ultimately included in the study according to inclusion criteria. Maximum intensity projection images were scored for image quality of each segmental hepatic artery. Potential determining factors for image quality were diaphragmatic motion, portal vein enhancement, and hepatic artery-to-parenchyma enhancement ratio. The flow rate of contrast media, x-ray delay, and location of the catheter tip were also evaluated. RESULTS: It was possible to trace at least subsegmental hepatic arteries in 625 of 700 segments (89.3%) on cone-beam CT hepatic arteriography. Diaphragmatic motion, prominent portal vein enhancement, and low hepatic artery-to-parenchyma enhancement ratio worsened image quality (P < .001, P = .022, and P = .017). Owing to cardiac motion artifacts, image quality of the left lateral segments (S2 and S3) was poorer compared with the remaining hepatic segments (S4-S8). CONCLUSIONS: In most cases, the quality of cone-beam CT hepatic arteriography images was good enough to trace subsegmental hepatic arteries at a minimum. Respiratory and cardiac motion, portal vein enhancement, and hepatic artery-to-parenchyma enhancement ratio significantly affected the image quality of cone-beam CT hepatic arteriography.

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.

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.

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.

Development of diaphragmatic weakness after transcatheter arterial chemoembolization of the right inferior phrenic artery: frequency and determinant factors.

PURPOSE: To assess the frequency of diaphragmatic weakness and its determinant factors after transcatheter arterial chemoembolization of the right inferior phrenic artery (IPA) in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: From June 2006 to October 2006, 60 patients (48 men, 12 women; mean age, 59 years) who had undergone chemoembolization of the right IPA underwent follow-up angiography of the right IPA and fluoroscopic diaphragmatic movement assessment. Diaphragmatic weakness was determined by the presence of paradoxical or decreased movement at fluoroscopy. As determinant factors, the extent of embolization (selective chemoembolization of the anterior or posterior branch vs nonselective chemoembolization), the use of gelatin sponge pledgets, additional cisplatin infusion, the size of a tumor supplied by the right IPA (>or=48 mm vs <48 mm), multiplicity of right IPA chemoembolization, and the extent of occlusive changes (single vs both branches) at follow-up right IPA angiography were assessed. The chi(2) and logistic regression tests were used to identify determinant factors of diaphragmatic weakness. RESULTS: Diaphragmatic weakness occurred in 11 of the 60 patients (18%). All 11 patients complained of shoulder pain during chemoembolization, but persistent dyspnea did not develop. Nonselective embolization (P = .005) and occlusive changes of both right IPA branches at follow-up angiography (P = .002) were significant determinant factors, as determined with univariate analysis. As determined with multivariate analysis, an occlusive change of both right IPA branches was the only significant determinant factor (P = .009; odds ratio, 17.2). Diaphragmatic weakness developed in 10 of the 28 patients (36%) with occlusive changes of both right IPA branches and only one (3.1%) of the remaining 32 patients. CONCLUSIONS: When chemoembolization of the right IPA is nonselectively performed and with permanent occlusive changes of the right IPA, diaphragmatic weakness can develop in one-third of patients as an ischemic complication.

Venous reflux from the pelvis and vulvoperineal region as a possible cause of lower extremity varicose veins: diagnosis with computed tomographic and ultrasonographic findings.

OBJECTIVE: The aim of this study was to demonstrate with the use of computed tomography and ultrasonography that isolated venous reflux from the pelvis and vulvoperineal region is a possible cause of lower extremity varicose veins. METHODS: From a consecutive series of patients who were referred to the vascular imaging laboratory, we retrospectively selected patients who had unusual lower extremity varicose veins that arose from the pelvis and vulvoperineal region. Computed tomographic venography and ultrasonograhy were used to exclude other causes of varicose veins. We reviewed medical records to evaluate the presence of pelvic congestion syndrome. Computed tomographic findings were reviewed to locate ovarian vein dilatation. RESULTS: Twenty limbs of 15 female patients (age range, 33-72 years; mean age, 53.2 years) were diagnosed with varicose veins that arose from the pelvis and vulvoperineal region without any saphenofemoral insufficiency. Eleven patients (73.3%) had no history of chronic pelvic pain. Four patients (26.7%) presented with chronic pelvic pain without any other evident gynecological etiology. Dilatation of the left ovarian vein was seen in 10 patients (67%; mean dilatation, 8.6 mm; range, 7.5-9.6 mm). Five patients (33%; mean dilatation, 4.9 mm; range, 3.8-6.6 mm) showed no ovarian vein dilatation. CONCLUSIONS: The combined use of computed tomographic venography and ultrasonography may be a possible noninvasive method for the diagnosis of unusual lower extremity varicose veins. Venous reflux from the pelvis and vulvoperineal region as a cause of lower extremity varicose veins can manifest without evidence of pelvic congestion syndrome or ovarian vein dilatation.

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.

Effectiveness of drug-eluting bead transarterial chemoembolization versus conventional transarterial chemoembolization for small hepatocellular carcinoma in Child-Pugh class A patients.

BACKGROUND: This study aimed to compare the therapeutic effectiveness including progression-free survival (PFS), overall survival (OS), and safety of conventional transarterial chemoembolization (cTACE) and drug-eluting bead transarterial chemoembolization (DEB-TACE) in a superselective fashion for the patients with nodular hepatocellular carcinoma (HCC) (n ⩽ 5) and Child-Pugh class A. METHODS: A total of 198 consecutive patients with nodular HCCs (n ⩽ 5) and Child-Pugh class A liver function who were initially treated with cTACE (n = 125) or DEB-TACE (n = 57) were included retrospectively. The primary endpoint was PFS. Secondary endpoints included time-to-target lesion progression (TTTLP), OS, and safety. RESULTS: The median follow up was 62 months (range, 1-87 months). The PFS was significantly longer in the cTACE group than in the DEB-TACE group (median, 18 months versus 7 months; hazard ratio [HR] = 0.658, log-rank p = 0.031), whereas OS was comparable (log-rank p = 0.299). TTTLP was significantly longer in the cTACE group than in the DEB-TACE group (median, 34 months versus 11 months; log-rank p < 0.001). In the stratification analysis based on tumor size, the cTACE group showed significantly longer TTTLP than the DEB-TACE group in the 1.0-2.0 cm and 2.1-3.0 cm subgroups (HR = 0.188, log-rank p < 0.001 and HR = 0.410, p = 0.015, respectively) but not in the 3.1-5.0 cm and 5.1-10.0 cm subgroups (all p > 0.05). Postembolization syndrome occurred more frequently in the cTACE group than in the DEB-TACE group (p = 0.006). CONCLUSIONS: DEB-TACE is followed by significantly shorter PFS than cTACE in patients with nodular HCCs (n ⩽ 5) and Child-Pugh class A, although OS is comparable. Postembolization syndrome occurs more frequently in cTACE than in DEB-TACE.

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.

CT angiography for living kidney donors: accuracy, cause of misinterpretation and prevalence of variation.

OBJECTIVE: To determine the accuracy of the use of multi-detector row CT (MDCT) to predict vascular anatomy in living kidney donors and to reveal the prevalence of vascular variations in a Korean population. MATERIALS AND METHODS: A total of 153 living kidney donors that had undergone preoperative CT and nephrectomy, either with open or laparoscopic surgery, were selected retrospectively. The initial CT results were compared with the surgical findings and repeated review sessions of CT scans were performed to determine the causes of mismatches in discordant cases. RESULTS: The accuracy of CT angiography was 95% to predict the number of renal vessels. Four arteries and two veins were missed during the initial CT interpretation due to perception errors (for two arteries and two veins) and technical limitations (two arteries). The prevalence of multiple renal arteries and veins, early branching of a renal artery and late confluence of a renal vein were 31%, 5%, 12%, 17%, respectively. The circumaortic renal vein and the bilateral inferior vena cava were found in two cases each (1.3%). One case (0.7%) each of a retroaortic renal vein and a supradiaphragmatic originated renal artery were found. CONCLUSION: MDCT provides a reliable method to evaluate the vascular anatomy and variations of living kidney donors.

A new and simple practical plane dividing hepatic segment 2 and 3 of the liver: evaluation of its validity.

OBJECTIVE: The conventional method of dividing hepatic segment 2 (S2) and 3 (S3) is subjective and CT interpretation is unclear. The purpose of our study was to test the validity of our hypothesis that the actual plane dividing S2 and S3 is a vertical plane of equal distance from the S2 and S3 portal veins in clinical situations. MATERIALS AND METHODS: We prospectively performed thin-section iodized-oil CT immediately after segmental chemoembolization of S2 or S3 in 27 consecutive patients and measured the angle of intersegmental plane on sagittal multiplanar reformation (MPR) images to verify its vertical nature. Our hypothetical plane dividing S2 and S3 is vertical and equidistant from the S2 and S3 portal veins (vertical method). To clinically validate this, we retrospectively collected 102 patients with small solitary hepatocellular carcinomas (HCC) on S2 or S3 the segmental location of which was confirmed angiographically. Two reviewers predicted the segmental location of each tumor at CT using the vertical method independently in blind trials. The agreement between CT interpretation and angiographic results was analyzed with Kappa values. We also compared the vertical method with the horizontal one. RESULTS: In MPR images, the average angle of the intersegmental plane was slanted 15 degrees anteriorly from the vertical plane. In predicting the segmental location of small HCC with the vertical method, the Kappa value between CT interpretation and angiographic result was 0.838 for reviewer 1 and 0.756 for reviewer 2. Inter-observer agreement was 0.918. The vertical method was superior to the horizontal method for localization of HCC in the left lobe (p < 0.0001 for reviewers 1 and 2). CONCLUSION: The proposed vertical plane equidistant from S2 and S3 portal vein is simple to use and useful for dividing S2 and S3 of the liver.

Cone-Beam Computed Tomography (CBCT) Hepatic Arteriography in Chemoembolization for Hepatocellular Carcinoma: Performance Depicting Tumors and Tumor Feeders.

PURPOSE: This study was designed to analyze retrospectively the performance of cone-beam computed tomography (CBCT) hepatic arteriography in depicting tumors and their feeders and to investigate the related determining factors in chemoembolization for hepatocellular carcinoma (HCC). METHODS: Eighty-six patients with 142 tumors satisfying the imaging diagnosis criteria of HCC were included in this study. The performance of CBCT hepatic arteriography for chemoembolization per tumor and per patient was evaluated using maximum intensity projection images alone (MIP analysis) or MIP combined with multiplanar reformation images (MIP + MPR analysis) regarding the following three aspects: tumor depiction, confidence of tumor feeder detection, and trackability of tumor feeders. Tumor size, tumor enhancement, tumor location, number of feeders, diaphragmatic motion, portal vein enhancement, and hepatic artery to parenchyma enhancement ratio were regarded as potential determining factors. RESULTS: Tumors were depicted in 125 (88.0 %) and 142 tumors (100 %) on MIP and MIP + MPR analysis, respectively. Imaging performances on MIP and MIP + MPR analysis were good enough to perform subsegmental chemoembolization without additional angiographic investigation in 88 (62.0 %) and 128 tumors (90.1 %) on per-tumor basis and in 43 (50 %) and 73 (84.9 %) on per-patient basis, respectively. Significant determining factors for performance in MIP + MPR analysis on per tumor basis were tumor size (p = 0.030), tumor enhancement (0.005), tumor location (p = 0.001), and diaphragmatic motion (p < 0.001). CONCLUSIONS: CBCT hepatic arteriography provided sufficient information for subsegmental chemoembolization by depicting tumors and their feeders in the vast majority of patients. Combined analysis of MIP and MPR images was essential to enhance the performance of CBCT hepatic arteriography.

Role of CT venography in the diagnosis and treatment of benign thoracic central venous obstruction.

OBJECTIVE: To evaluate the role of CT venography in the diagnosis and treatment of benign thoracic central venous obstruction. MATERIALS AND METHODS: Eighteen patients who had undergone both CT venography and digital subtraction venography were prospectively enrolled in this study. The following features were analyzed by two observers: the cause, degree, and extent of venous obstruction; associated thrombosis; and implications for the planning of treatment. CT venography and digital subtraction venography were compared in defined venous segments, and the degree of obstruction, and correlation was expressed using Spearman's rank correlation coefficient. RESULTS: In all patients, CT venography depicted the causes of obstruction, including extrinsic compression of the left brachiocephalic vein, and mediastinal inflammatory pseudotumor. Interobserver agreement regarding classification of the degree of obstruction was judged as good for CT venography (K=0.864), and in evaluating this, there was significant correlation between CT venography and digital subtraction venography (reader 1: Rs = 0.58, p < 0.01; reader 2: Rs = 0.56, p < 0.01). In evaluating the status of central veins proximal to long segmental obstruction, and associated thrombosis, CT venography was superior to digital subtraction venography. In half of all patients, the findings of CT venography led to changes in the treatment plan. CONCLUSION: The findings of CT venography correlated closely with those of digital subtraction venography, and the former accurately depicted the degree and extent of benign venous obstruction.

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 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.

Subtraction CT angiography of the lower extremities: single volume subtraction versus multi-segmented volume subtraction.

RATIONALE AND OBJECTIVES: To validate the hypothesis that a multisegmented approach during subtraction computed tomography (CT) angiography of the lower extremities can improve bone removal efficiency by suppressing regional motion. MATERIALS AND METHODS: The institutional review board of our hospital approved this retrospective study. One hundred and one consecutive patients that had undergone the lower extremity CT angiography were included in this study. Subtraction CT angiography was performed using two different methods, namely, by single volume subtraction and by multisegmented volume subtraction. Multisegmented volume subtraction was conducted by dividing the whole volume of the CT data into three segments along the z axis of the lower extremities, performing a subtraction process for each segment, and combining segments to form as single subtracted volume. The bone removal efficiencies of the two methods was assessed by analyzing bone subtraction scores on maximum intensity projection (MIP) images for each bone segment in a blinded fashion. In addition, overall MIP image qualities were compared by displaying MIP images produced using the two methods side by side. Differences between bone subtraction scores were tested using Wilcoxon's signed rank test. RESULTS: Multisegmented volume subtraction MIP images demonstrated significantly better bone removal for the following bone segments: pelvis (P < .0001), hip (P = .0002), thigh (P = .0258), knee (P = .0004), ankle (P = .0008), metatarsal bone (P < .0001), and toes (P < .0001). Overall bone subtraction score and subjective image qualities determined by performing side-by-side comparisons were better for the multisegmented volume subtraction method. CONCLUSION: Bone removal performance and overall MIP image quality can be increased by adopting multisegmented volume subtraction during subtraction CT angiography 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.

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 subject's 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.

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

OBJECTIVE: 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.