Three-Dimensional Multislice Helical Computed Tomography with the Volume Rendering Technique in the Detection of Vascular Complications After Liver Transplantation (original) (raw)
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Three-dimensional CT angiography of the canine hepatic vasculature
Journal of Veterinary Science, 2008
Eight Beagle dogs were anesthetized and were imaged using a single channel helical CT scanner. The contrast medium used in this study was iohexol (300 mg I/ml) and doses were 0.5 ml/kg for a cine scan, 3 ml/kg for an enhanced scan. The flow rate for contrast material administration was 2 ml/sec for all scans. This study was divided into three steps, with unenhanced, cine and enhanced scans. The enhanced scan was subdivided into the arterial phase and the venous phase. All of the enhanced scans were reconstructed in 1 mm intervals and the scans were interpreted by the use of reformatted images, a cross sectional histogram, maximum intensity projection and shaded surface display. For the cine scans, optimal times were a 9-sec delay time post IV injection in the arterial phase, and an 18-sec delay time post IV injection in the venous phase. A nine-sec delay time was acceptable for the imaging of the canine hepatic arteries by CT angiography. After completion of arterial phase scanning, venous structures of the liver were well visualized as seen on the venous phase.
Liver Transplantation, 2010
Because hepatic vasculatures exhibit variations, a preoperative evaluation of the vascular anatomy and an estimation of the volume of the liver graft are essential for successful adult living donor liver transplantation. Using 3-dimensional (3D) computed tomography (CT), we analyzed the volumetric and anatomical relationship of the hepatic vasculatures of liver grafts. The livers of 223 potential donors were analyzed by 3D CT. Volumetric analysis was performed for each hepatic vein and its tributaries. The anatomy of the portal vein and hepatic artery was assessed along with the biliary system via intraoperative cholangiography in 110 recipients. On the basis of the anatomical presentation of the inferior right hepatic vein (IRHV), the hepatic veins were classified as follows: in type I, the IRHV was absent; in type II, the IRHV was smaller than the right hepatic vein (RHV); and in type III, the IRHV was greater than or equal to the RHV in size. The drainage volume of the middle hepatic vein (MHV) and especially its tributaries in the right lobe increased with the size of the IRHV (P < 0.001). In type III hepatic veins with a large IRHV (17% of the donors), the MHV tributaries had the largest drainage volume in the right lobe (41.2% 6 11.8%). Furthermore, type III hepatic veins typically exhibited biliary variations in 75% of the donors. No correlation was observed between variations in the hepatic artery and portal vein. In conclusion, a right lobe graft with a large IRHV is accompanied by a large drainage volume via the MHV and by bile duct variations in 17% of livers. Therefore, anatomical and volumetric analysis is important for preoperative evaluations.
Transplantation Proceedings, 2004
Anatomical variations in the venous system of liver are not a rarity. A prospective helical computerized tomography (CT) study was undertaken to determine the prevalence of surgically significant hepatic venous anatomic variations among 100 consecutive living liver donors. The studies evaluated the ramification pattern of hepatic veins, the presence of accessory hepatic veins, and of segment 5 or 8 veins (or both) draining into middle hepatic vein. These data obtained by CT influenced surgical planning. Sixty-four donors donated their right lobes and 24 donors, left lateral segments. Only one donor candidate was refused due to combined hepatic and portal venous variations accompanied by multiple bile ducts. Eleven donors were also refused due to reasons other than anatomical variations. Seventeen segment 5 and 17 segment 8 veins draining into middle hepatic vein were anastomosed to inferior vena cava in 23 (36%) of the right lobe liver transplantations. The middle hepatic vein was harvested in only one of the donors. Among the 100 cases, 47 had accessory right inferior hepatic veins, 13 of which were multiple. Twenty-two of the right lobe grafts required surgical anastomoses of these accessory hepatic veins (34%). An isolated hepatic vein anomaly or the presence of accessory hepatic veins are not contraindications to be a living liver donor candidate. However, preoperative knowledge of vascular variations alters surgical management. Helical CT is a valuable tool to delineate the hepatic venous anatomy for surgical planning in living liver donors.
Multimodality Imaging of Normal Hepatic Transplant Vasculature and Graft Vascular Complications
Journal of Clinical Imaging Science, 2011
Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Postoperative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.
Radiology, 2003
PURPOSE: To evaluate relevant arterial and venous anatomy of the hepatectomy plane lateral to segment IV by using multi-detector row computed tomography (CT) with respect to adult living related transplantation of the right lobe of the liver. MATERIALS AND METHODS: In potential liver donors, 100 consecutive hepatic CT angiograms were obtained after intravenous bolus administration of 150-180 mL of nonionic contrast material. Arterial phase images (1.25-mm collimation, 7.5 mm/ 0.8-second table speed) were acquired after test dose injection. Portal phase images were acquired at 60 seconds (2.5-mm collimation, 15 mm/0.8-second table speed). Postprocessing depicted arterial, portal, and hepatic vein anatomy traversing the anticipated surgical hepatectomy plane to the right of the middle hepatic vein (MHV) and separating the right and left lobes of the liver. Two radiologists interpreted the images, and data were agreed on by consensus. Data collected included intrahepatic anatomy and origin of the artery and vein supplying segment IV; the venous drainage from segments V and VIII; and the presence, size, and distance from the right hepatic vein (RHV) confluence of accessory hepatic veins in the surgical plane. RESULTS: Thirty-one donors had conventional hepatic vascular anatomy. Vessels that traversed the hepatectomy plane included the artery supplying segment IV in seven (7%) patients, dominant portal vein supply to segment IV from the right portal vein in two (2%) patients or from both right and left portal vein branches in three (3%) patients, segment VIII draining into the MHV in 67 (67%) patients or both the MHV and RHV in 18 (18%) patients (the major draining vein was Ͼ7 mm in diameter in 23%), segment V draining into the MHV in 10 (10%) patients, or both the MHV and RHV in 19 (19%) patients (the major draining vein from segment V was 7-10 mm in diameter in 70 patients, and larger than 10 mm in five). Forty-four accessory hepatic veins were identified in 40 patients; seven drained segment V, while the majority drained segments VI and VII. The mean diameter was 5.3 mm and 45% were larger than 6 mm. The average distance to the RHV-inferior vena cava confluence was 28.7 mm. Of 70 patients with drainage from segment V into RHV, 22 (31%) had an accessory RHV. However, atypical drainage into the MHV was noted in seven (70%) of 10 patients and into the MHV and RHV in 11 (58%) of 19 patients. CONCLUSION: In the majority of potential donors, CT angiography depicted a wide range of vascular anatomic variations that traverse the hepatectomy plane.
TURKISH JOURNAL OF VETERINARY AND ANIMAL SCIENCES, 2013
Our focus has been to study and compare the anatomical helical computed tomography (CT) features of the normal rabbit liver with its native cross-sectional anatomy. Helical CT was used for scanning the cranial part of the abdominal cavity. The slice thickness was 5 mm. Frozen transversal anatomic cross-sections with a thickness of 10 mm were obtained from the cranial abdominal part of 4 animals following euthanasia. They were compared with the corresponding helical CT scans. At Th9 (thoracic vertebra), the helical CT images showed in the whole aspect a normal liver. It was a massive, heterogeneous, soft tissue, with normal attenuating findings and distinguished edges. The gallbladder was hypoattenuated compared to the liver parenchyma. At the level of Th11 the liver was in sharp distinction to the fundus and body of the stomach. At Th12 the rabbit liver was found in close contact with the stomach, duodenum, and ascending colon. Only the right hepatic lobe was visible at the level of Th13, outlined by the right kidney impression. The right hepatic and caudate lobe were observed at L1 (lumbar vertebra). The frozen cross-sections have analogues to the corresponding helical CT images. That motivated us to conclude that helical CT is an accurate mode for studying the rabbit liver anatomy.
European Radiology, 2006
Objective The purpose was to assess the volumes of the different hepatic territories and especially the drainage of the right paramedian sector in adult living donor liver transplantation (ALDLT). Methods CT was performed in 40 potential donors of whom 28 underwent partial living donation. Data sets of all potential donors were postprocessed using dedicated software for segmentation, volumetric analysis and visualization of liver territories. During an initial period, volumes and shapes of liver parts were calculated based on the individual portal venous perfusion areas. After partial hepatic congestion occurring in three grafts, drainage territories with special regard to MHV tributaries from the right paramedian sector, and the IRHV were calculated additionally. Results were visualized three-dimensionally and compared to the intraoperative findings. Results Calculated graft volumes based on hepatic venous drainage and graft weights correlated significantly (r=0.86, P<0.001). Mean virtual graft volume was 930 ml and drained as follows: RHV: 680 ml, IRHV: 170 ml (n=11); segment 5 MHV tributaries: 100 ml (n=16); segment 8 MHV tributaries: 110 ml (n=20). When present, the mean aberrant venous drainage fraction of the right liver lobe was 28%. Conclusion The evaluated protocol allowed a reliable calculation of the hepatic venous draining areas and led to a change in the hepatic venous reconstruction strategy at our institution.
Triple-Phase Multidetector Computed Tomography in Distinguishing Canine Hepatic Lesions
Animals
The liver has a unique vascular supply, and triple-phase contrast-enhanced computed tomography examinations are being performed in order to characterize liver lesions. This study aimed to look for any associations between the attenuation values of liver lesions and their histological classification. The inclusion criteria for this retrospective study were focal or multifocal liver lesions and histological diagnosis. All of the dogs underwent pre-contrast and triple-phase postcontrast computed tomography (CT) examinations with identical timings of the postcontrast series. Thirty-one dogs were included in the study, and various benign and malignant pathologies were identified. The results did not identify any significant differences between the benign and malignant liver lesions, nor between the individual histological diagnoses. Inflammatory lesions were significantly different compared to the normal liver parenchyma, and significant hypoattenuation was found in the portal and delaye...
COMPUTERIZED CT BASED 3D VISUALIZATION TECHNIQUE IN LIVING RELATED LIVER TRANSPLANTATION
Transplantation Journal, 2004
For living donor liver transplantation (LDLT) accurate diagnostic workup is essential. Multiple imaging approaches are currently used. Problems arise in the assessment of vascular and bile duct anatomy, liver graft volume, and vascular territories involved. A 3D visualization system that improves anatomic assessment, allows interactive surgery planning, and acts as an intraoperative guide with enhanced precision is required. Refinements in computed tomography (CT) technology with the introduction of multidetector-row CT scanners and implementation of mathematical methods on computerized digital data has enabled CT-based 3D visualizations. Sixteen LDLT candidates and three LDLT recipients were assessed by multislice CT examination. Image processing of the digital raw data for 3D visualization included segmentation and calculation of center lines. A hierarchical mathematical model representing the vascular and biliary tree was created. This allowed calculation of individual vascular territories. 3D CT-based visualization in LDLT facilitates diagnostic workup with high accuracy for analyses of vascular and bile duct variants, volumetry, and assessment of the optimal surgical splitting line of the living donor liver. Resultant areas of either arterial devascularization or venous congestion can be displayed and quantified preoperatively. The diagnostic method is of major impact on patient selection and directly influences intraoperative surgical guidance. The currently practiced &amp;amp;amp;quot;multiple imaging approach&amp;amp;amp;quot; approach, especially with regard to invasive diagnostics, can be avoided in the future.