Cihan Duran

Clinical situations in which coronary CT angiography confers superior diagnostic information compared with coronary angiography

In this review, we aimed to outline the clinical and pathological conditions for which multidetector computed tomography coronary angiography (MDCT-CA) should be the preferred method because of its advantages over conventional coronary angiography (CCA). A consistent body of literature suggests that MDCT-CA is more than just complementary to CCA and that it provides more valuable diagnostic information in certain clinical situations, such as complex coronary artery variations, aorto-ostial lesions, follow-up of bypass grafts, myocardial bridging, coronary artery fistulas, aortic and coronary artery dissections, and cases in which the coronary ostia cannot be cannulated by a catheter because of massive atherosclerosis or extremely tortuous vascular structures.

Hepatic arterial mapping by multidetector computed tomographic angiography in living donor liver transplantation.

Purpose: Our aims were to present the hepatic arterial variations that were detected with computed tomographic angiography (CTA) and confirmed by operation in living liver donors and to emphasize the usefulness of CTA in the assessment of hepatic arterial anatomy. Materials and Methods: The donors of 100 patients (46 women and 54 men) who had undergone a living donor liver transplantation in a (blinded) hospital between July 2004 and June 2007 were evaluated. The age of the donors ranged from 18 to 63 years (mean, 39 years). The CTA images obtained by a 16-slice multidetector CT before the transplantation procedure were retrospectively evaluated for arterial variations, and the results were compared with the results of the operation. Results: In 59 donors (59%), classic hepatic arterial anatomy was observed. In the remaining 41 donors (41%), various arterial variations were determined. In 11 of the donors (11%), variations were not compatible with the description of Michels classification. In all of our patients, CTA findings were confirmed with operational findings. Our complication rate was 1%. Only 1 of the patients who had undergone the transplantation developed hepatic arterial thrombus, and the remaining 99 patients had no arterial complications. Conclusions: The course of the vascular structures before live donor liver transplantation is essential for planning and success of the operation. Our study showed that multidetector CTA can be used successfully in hepatic artery imaging of liver transplantation donors as a noninvasive method.

An investigation of the association between coronary artery dominance and coronary artery variations with coronary arterial disease by multidetector computed tomographic coronary angiography.

Purpose: Depending on the perfusing interventricular septum of the arteries, there are 3 types of circulation dominance: right, left, and balanced. In this study, coronary artery branches supplying the ventricular septum were investigated in vivo in a large group of patients by multidetector computed tomography (MDCT) coronary angiography. In addition, the association of coronary artery variations with coronary arterial disease was investigated. Materials and Methods: The study included 325 consecutive patients (214 men and 108 women, with a mean age of 59 ± 14 years) who underwent MDCT coronary angiography. Multidetector computed tomography was performed with a 16-detector-row computed tomographic scanner. The type of dominance, coronary arterial diseases, and coronary artery variations were recorded. Results: In our study, the types of coronary circulation were right, left, and balanced in 227 (70%), 40 (12.5%), and 58 (17.5%) patients, respectively. Dominance of right circulation was detected in 150 of 217 (69%) of men and in 77 of 108 (71%) of women; dominance of left circulation was found in 26 of 217(12%) of men and in 14 of 108 (13%) of women; balanced/codominance circulation was found in 41 of 217 (19%) of men and in 17 of 108 (16%) of women. However, no significant differences were detected between the sexes for the type of coronary circulation. Coronary artery disease was determined in 68 patients (20.9%) by MDCT, and coronary artery variations were also determined in 34 patients (10.4%). Both the number and the rate of coronary artery variations were significantly higher among the patients with left artery dominance. Conclusions: Knowledge of coronary artery variations and pathologies is important in planning the treatment and in interpretation of findings of cardiovascular diseases. Our study indicated that, although right dominance circulation is more common in general population, both the coronary diseases and coronary artery variations are more common in individuals with left dominance circulation.

Living donor liver hilar variations: surgical approaches and implications

BACKGROUND Varied vascular and biliary anatomies are common in the liver. Living donor hepatectomy requires precise recognition of the hilar anatomy. This study was undertaken to study donor vascular and biliary tract variations, surgical approaches and implications in living liver transplant patients. METHODS Two hundred living donor liver transplantations were performed at our institution between 2004 and 2009. All donors were evaluated by volumetric computerized tomography (CT), CT angiography and magnetic resonance cholangiography in the preoperative period. Intraoperative ultrasonography and cholangiography were carried out. Arterial, portal and biliary anatomies were classified according to the Michels, Cheng and Huang criteria. RESULTS Classical hepatic arterial anatomy was observed in 129 (64.5%) of the 200 donors. Fifteen percent of the donors had variation in the portal vein. Normal biliary anatomy was found in 126 (63%) donors, and biliary tract variation in 70% of donors with portal vein variations. In recipients with single duct biliary anastomosis, 16 (14.4%) developed biliary leak, and 9 (8.1%) developed biliary stricture; however more than one biliary anastomosis increased recipient biliary complications. Donor vascular variations did not increase recipient vascular complications. Variant anatomy was not associated with an increase in donor morbidity. CONCLUSIONS Living donor liver transplantation provides information about variant hilar anatomy. The success of the procedure depends on a careful approach to anatomical variations. When the deceased donor supply is inadequate, living donor transplantation is a life-saving alternative and is safe for the donor and recipient, even if the donor has variant hilar anatomy.

Efficacy of ivabradin to reduce heart rate prior to coronary CT angiography: comparison with beta-blocker

PURPOSE The objective of our study was to assess the effect of ivabradine on image quality of ECG-gated multidetector computed tomography (MDCT) coronary angiography. MATERIALS AND METHODS Computed tomography coronary angiography (CTCA) was performed on two groups. In Group 1 (n=54), an intravenous beta-blocker was administered to patients with a heart rate >70 beats per minute (bpm) just before CTCA. In Group 2 (n=56), oral ivabradine 5 mg was administered twice a day for three days prior to CTCA examination to patients with a heart rate >70 bpm and contraindication to beta-blockers. Images acquired on two different MDCT scanners were scored in terms of image quality of the coronary artery segments using a 5-point grading scale (Grade 1, unreadable; Grade 5, excellent). RESULTS The mean heart rates during CTCA were 64 ± 6.7 bpm for Group 1 and 59 ± 4.1 bpm for Group 2 (P < 0.05). Mean heart rate reduction was 9 ± 5% and 14 ± 8% for Groups 1 and 2, respectively (P < 0.001). A total of 880 segments were evaluated in 110 patients. When the best reconstruction interval was used, 89.8% and 95.5% of all the coronary segments showed acceptable image quality in Groups 1 and 2, respectively. Acceptable image quality of the middle right coronary artery was obtained in 78.3% of Group 1 and 92.4% of Group 2. These ratios for the other segments were 88.4% for Group 1 and 95.2% for Group 2. CONCLUSION Reduction of heart rates with ivabradine premedication improves the image quality of CTCA. It should be considered as an alternative drug, particularly in patients with contraindications to beta-blockers.

Inferior Vena Cava Filter–Associated Abnormalities: MDCT Findings

OBJECTIVE Deep venous thrombosis from the pelvis or lower extremities has significant morbidity, and subsequent pulmonary embolism has a high mortality rate. Immediate anticoagulation in patients with deep venous thrombosis is crucial in preventing this lethal complication. However, in patients with contraindications for or failure of anticoagulation, inferior vena cava filters reduce mortality by decreasing the incidence of pulmonary embolism. CONCLUSION In this review, we discuss the various pathologic abnormalities related to inferior vena cava filters, as seen on MDCT images.

Living donor liver transplantation for hepatocellular carcinoma: a single center analysis of outcomes and impact of different selection criteria

We examined the outcomes of patients who received living donor liver transplantation (LDLT) for HCC comparing the impact of up‐to‐seven criteria and Asan Criteria (AC) with Milan Criteria (MC). Between July 2004 and July 2009, of 175 consecutive LDLT, there were 45 consecutive patients with HCC. Forty patients who completed 12 months follow‐up were enrolled. In search for the highest number of expansion, we selected AC as the extended criteria. Patients were divided into having tumors within MC, beyond MC within AC and Beyond Criteria (BC) groups. With a median follow‐up of 46 months, overall 1, 3, and 5 years survival was −90%, −81%, and −70%, respectively. In patients within AC, estimated mean survival was 49.8 vs. 40.5 months for BC group (P = 0.2). Disease‐free survival was significantly higher in patients within AC comparing with BC group; 48.0 vs. 38.6 months (P = 0.04). Preoperative AFP level >400 and poor tumor differentiation were factors adversely effecting recipient survival. On multivariate analysis, the presence of poor tumor differentiation (P = 0.018 RR: 2.48) was the only independent predictor of survival. Extension of tumor size and number to AC is feasible, without significantly compromising outcomes; however, the presence of poor tumor differentiation was associated with worse outcomes after LDLT.

Pulmonary Arteriovenous Malformation (PAVM): Multidetector Computed Tomography Findings.

A 30-year-old woman was referred to our department for multidetector computed tomography (MDCT) with a complaint of dyspnea. Her chest radiography findings were unremarkable. Wide area detector CT Angiography and contrast-enhanced CT scan revealed an enhancing cluster of tubular structures in the inferior lingular segment of the left upper lobe [1, 2]. Coronal maximum intensity projection (MIP) (Figure A) and three-dimensional volume-rendered CT images (Figures B, C) revealed a Pulmonary Arteriovenous Malformation PAVM with a feeding artery, an aneurysmal part, and a draining vein.

May-Thurner Syndrome: A Case Report

May-Thurner Syndrome (MTS) or iliac vein compression syndrome is caused by compression of the left common iliac vein by the right common iliac artery. This obstruction may cause leg swelling, varicosities, deep venous thrombosis, chronic venous stasis ulcers, or more serious complications, such as pulmonary embolism. Iliac vein compression can be assessed with computed tomography (CT) and iliac venography. The goals of treatment are to reduce symptoms and to reduce the risk of complications. Stent placement is an alternative method to a direct surgical approach. We present a case of MTS, treated with stent placement.

Comparison of Low-Dose Higher-Relaxivity and Standard-Dose Lower-Relaxivity Contrast Media for Delayed-Enhancement MRI: A Blinded Randomized Crossover Study

OBJECTIVE The gadolinium-based MRI contrast agent gadobenate dimeglumine has nearly twice the MR relaxivity of gadopentetate dimeglumine at 1.5 T. The purpose of this study was to determine whether a lower dose (0.1 mmol/kg) of gadobenate dimeglumine can be used to obtain delayed-enhancement MR images comparable to those obtained with a standard dose (0.2 mmol/kg) of gadopentetate dimeglumine. SUBJECTS AND METHODS In this blinded randomized crossover study, 20 patients with known myocardial infarction underwent two separate delayed-enhancement MRI examinations after receiving 0.1 mmol/kg gadobenate dimeglumine and 0.2 mmol/kg gadopentetate dimeglumine (random administration). The conspicuity of lesion enhancement 5, 10, and 20 minutes after contrast administration was quantified as relative enhancement ratio (RER). RESULTS With either gadolinium-based contrast agent, damaged myocardium had higher signal intensity than normal remote myocardium (RER > 4) on delayed-enhancement MR images, and the blood RER declined over time after contrast administration. The blood RER was not significantly higher for gadobenate dimeglumine than for gadopentetate dimeglumine at 5 and 10 minutes. Nevertheless, there was a larger reduction in blood RER for gadobenate dimeglumine than for gadopentetate dimeglumine between 5 and 10 minutes and between 10 and 20 minutes. The volumes of enhancement were similar for gadobenate dimeglumine (13.6 ± 8.8 cm(3)) and gadopentetate dimeglumine (13.5 ± 8.9 cm(3)) (p = 0.98). The mean difference in Bland-Altman analysis for delayed-enhancement volume between the agents was 0.1 cm(3). CONCLUSION Qualitatively and quantitatively, delayed-enhancement MR images of ischemic myocardium obtained with 0.1 mmol/kg gadobenate dimeglumine are comparable to those obtained with 0.2 mmol/kg gadopentetate dimeglumine 5, 10, and 20 minutes after contrast administration.