Relationship between vascular and biliary anatomy in living liver donors

OBJECTIVE: The objective of our study was to determine whether there is an association between portal venous or hepatic arterial branching patterns (or both) and biliary anatomic variants. MATERIALS AND METHODS: Two radiologists independently reviewed preoperative hepatic CT scans and intraoperative cholangiograms from 39 consecutive living liver donors. The portal venous and hepatic arterial anatomy was classified on the basis of the preoperative CT scans and the biliary anatomy was classified on the basis the intraoperative cholangiograms into one of two groups: conventional or anomalous. Variables were tested for association using Fisher's exact test. RESULTS: Anomalous vascular branching variants were common, being present in 23 (59%) of 39 patients. Hepatic arterial anomalies were present in 18 (46%); portal venous anomalies, in seven (18%); and both, in two (5%). Biliary anomalies were present in 15 (38%) of the 39 patients. Of the 23 patients with anomalous vascular anatomy, seven (30%) had biliary anomalies. Of the 16 patients with conventional vascular anatomy, eight (50%) had biliary anomalies. There was no significant association between hepatic arterial anomalies, portal venous anomalies, or the combination of arterial and portal venous anomalies and anomalous biliary drainage. CONCLUSION: Portal venous and hepatic arterial branching patterns do not correlate well with biliary anatomic variants. In patients with normal hepatic vascular anatomy, biliary anomalies are common.     

Potential living liver donors: evaluation with an all-in-one protocol with multi-detector row CT

Multi-detector row computed tomography was performed for the preharvest evaluation of 14 potential living liver donors. Both a biliary contrast agent and a conventional iodinated contrast agent were administered intravenously. This protocol included acquisition of three subsequent scans and allowed accurate assessment of the hepatic parenchymal morphology and volumetrics and a detailed analysis of the biliary and vascular anatomies.     

Hereditary hemorrhagic telangiectasia: multi-detector row helical CT assessment of hepatic involvement

PURPOSE: To describe findings obtained with multi-detector row helical computed tomography (CT) of the liver in patients with hereditary hemorrhagic telangiectasia. MATERIALS AND METHODS: Multiphasic multi-detector row helical CT was performed in 70 consecutive patients (29 females and 41 males; mean age, 48.5 years; age range, 15-75 years): 64 considered to have hereditary hemorrhagic telangiectasia and six suspected of having the disease. Scanning delay was achieved by using a test bolus of contrast medium to obtain early arterial phase, late arterial phase, and portal venous phase images. Multiplanar and angiographic reconstructions were then generated. The presence of shunts, hepatic perfusion disorders, telangiectases, other vascular lesions, indirect signs of portal hypertension, and vascular anatomic variants were evaluated by two radiologists in consensus. RESULTS: Fifty-two of 70 (74%) patients had hepatic vascular abnormalities. Only four of 52 (8%) patients were symptomatic. Arterioportal shunts were present in 27 of 52 (52%) patients, arteriosystemic shunts in eight of 52 (15%), and both shunt types in 17 of 52 (33%). In 34 of 52 (65%) patients, parenchymal perfusion disorders were detected. Telangiectases were found in 33 of 52 (63%) patients. Large confluent vascular masses were identified in 13 of 52 (25%) patients. In 31 of 52 (60%) patients, indirect CT signs of portal hypertension were detected, but only one had clinical signs of this condition. Vascular anatomic variants were detected in seven patients (13%). CONCLUSION: Multi-detector row helical CT and reconstructions depict the complex hepatic vascular alterations typical of hereditary hemorrhagic telangiectasia.     

Multi-detector row helical CT of the liver: quantitative assessment of iodine concentration of intravenous contrast material on multiphasic CT--a prospective randomized study

PURPOSE: The purpose of this study was to assess the quantitative effects of contrast material concentration on hepatic parenchymal and vascular enhancement in multiphasic computed tomography (CT), using multi-detector row helical CT. MATERIALS AND METHODS: We designed a prospective randomized study to test two different concentrations of contrast material on five phasic scans of the liver. One hundred patients were randomly assigned to two groups: an iodine concentration of 300 mg/mL in group A and 370 mg/mL in group B. All patients received a fixed volume of 100 mL at a 4 mL/sec injection rate. Enhancement values for the hepatic parenchyma and aorta at three levels (upper, middle, and lower level of the liver), and values for portal and hepatic veins were statistically compared between the two groups. RESULTS: Hepatic parenchymal enhancement values at all levels of the liver in portal phase (PP) and equilibrium phase (EP) were significantly higher in group B than in group A (p<0.01). Aortic enhancement values at two levels of the liver (middle and lower) in early hepatic arterial phase (EAP) were significantly higher in group B than in group A (p<0.05), however, there was no significant difference between groups A and B in aortic enhancement during the delayed hepatic arterial phase (DAP). Portal and hepatic venous enhancement values in PP and EP were significantly higher in group B than in group A (p<0.01). CONCLUSION: On multiphasic dynamic CT, the use of a higher iodine concentration of contrast material results in higher hepatic parenchymal enhancement and aortic enhancement, as well as higher portal and hepatic venous enhancement.     

Virtual Monoenergetic Spectral Detector CT for Preoperative CT Angiography in Liver Donors

ObjectiveThe purpose of this study was to evaluate the use of virtual monoenergetic images (VMI) in pre-operative CT angiography of potential donors for living donor adult liver transplantation (LDALT), and to determine the optimal energy level to maximize vascular signal-to-noise and contrast-to-noise ratios (SNR and CNR, respectively).Materials and methodsWe retrospectively evaluated 29 CT angiography studies performed preoperatively in potential liver donors on a spectral detector CT scanner. All studies included arterial, early venous, and delayed venous phase imaging. Conventional polyenergetic images were generated for each patient, as well as virtual monoenergetic images in 10 keV increments from 40 –100 keV. Arteries (aorta and celiac, superior mesenteric, common hepatic, right and left hepatic arteries) were assessed on arterial phase images; portal venous system branches (splenic, superior mesenteric, main, right, and left portal veins) on early venous phase images; and hepatic veins on late venous phase images. Vascular attenuation, background parenchymal attenuation, and noise were measured on each set of virtual monoenergetic and conventional images.ResultsBackground hepatic and vascular noise decreased with increasing keV, with the lowest noise at 100 keV. Vascular SNR and CNR increased with decreasing keV and were highest at 40 keV, with statistical significance compared with conventional ( P < 0.05).ConclusionsIn preoperative CT angiography for potential liver donors, the optimal keV for assessing the vasculature to improve SNR and CNR is 40 keV. Use of low keV VMI in LDALT CT protocols may facilitate detection of vascular anatomical variants that can impact surgical planning.     

多排螺旋CT双动脉期增强扫描对比剂浓度对肝癌检出率的影响

目的:通过多排螺旋CT双动脉期及门脉期增强扫描,以评估对比剂浓度对肝癌检出率的影响.方法:95例肝癌患者随机分为两组行多排螺旋CT肝脏平扫及双动脉期、门脉期增强扫描,其中一组(48例)注射碘帕醇370 mgI/ml( 1.5 ml/kg),另外一组(47例)注射碘帕醇300 mgI/ml (1.85ml/kg),均于30 s注射完毕.扫描后图像由放射科医生阅片并与病理结果进行对比,统计分析两组患者＞ 2cm及≤2cm的肝癌病灶的诊断敏感性.结果:95例患者中共证实有259个肝癌病灶,其中87个≤2cm,172个＞2cm.对于≤2cm的病灶及所有病灶动脉早期及晚期370 mgI/ml组诊断敏感性高于300 mgI/ml组,差别有统计学意义;在门脉期两组患者的诊断敏感性无显著性差异.结论:高浓密度对比剂在动脉早期、晚期可提高肝癌的检出率,特别是对于较小的肝癌病灶(≤2cm).     

Hepatic arteries in potential donors for living related liver transplantation: evaluation with multi-detector row CT angiography

PURPOSE: To assess the accuracy of multi-detector row computed tomographic (CT) angiography in the evaluation of hepatic arterial anatomy in living related liver transplantation (LRLT) donors. MATERIALS AND METHODS: During a 10-month period, 62 potential LRLT donors were evaluated with CT and conventional angiography. Multi-detector row CT was performed after intravenous injection of 150 mL of contrast material at 3 mL/sec. CT angiograms of the hepatic arteries were generated by a radiologist who used volume rendering and maximum intensity projection techniques without knowledge of results of conventional angiography. Two reviewers reviewed CT and conventional angiograms retrospectively in consensus. The results of the two examinations were then compared. RESULTS: CT examinations were technically adequate in 56 (90%) donors. Respiratory motion artifact compromised detailed hepatic artery analysis in six donors (10%). Second-order branches of right hepatic arteries were visualized in 58 donors (94%), and second-order branches of left hepatic arteries were visualized in 51 (82%). A total of 27 hepatic arterial anatomic variations were detected in 22 donors at conventional angiography. CT angiography accurately depicted 25 (93%) anatomic variations in 20 donors (91%). CT angiography did not depict an accessory right hepatic artery in two donors. The number and origins of dominant arteries supplying segment IV were accurately identified at CT angiography in 51 donors (82%). Hepatic arterial anatomy depicted at CT angiography was identical to that at conventional angiography in 50 donors (81%). CONCLUSION: Multi-detector row CT angiography is useful but limited in its ability to depict the dominant artery supplying segment IV and small accessory hepatic arteries.     

Spectrum of CT findings in pediatric patients after partial liver transplantation.

Liver transplantation is an accepted therapy for patients with severe liver diseases. In pediatric liver transplantation, the application of reduced-size and split-liver transplantation has expanded the donor pool. The development of living related donor partial liver transplantation has further increased the availability of donors. Complications in patients after living related transplantation include hepatic arterial thrombosis, portal venous stenosis and thrombosis, hepatic venous stenosis, biliary stenosis or leak, biloma formation, fatty liver, extrahepatic fluid collection, posttransplantation lymphoproliferative disorder, and organ rejection. Ultrasonography is the primary imaging modality for evaluation of the vascular system of patients after liver transplantation, and computed tomography is useful to help diagnose hepatic parenchymal abnormalities including infarction, congestion, and fatty change; intrahepatic biliary damage; and extrahepatic disorders, including abnormal fluid collections, varicose veins, and lymphadenopathy.     

Living donor liver transplantation in adults: vascular variants important in surgical planning for donors and recipients

OBJECTIVE: The purpose of our study was to explore the frequency with which surgically important hepatic vascular variants occur independently as well as in genetically related adult candidates for donation or receipt of a liver transplant. MATERIALS AND METHODS: We conducted a retrospective study of 107 adult living donor liver transplant candidates. From this pool of candidates, 50 sets of close relatives were selected to undergo transplantation. As part of the preoperative evaluation, all underwent multidetector CT angiography for evaluation of arterial and venous anatomy. Nonionic IV contrast material (180 mL) was given at a rate of 5 mL/sec, and collimations of 1.25 and 2.50 mm were used for true arterial and portal hepatic venous phase scanning, respectively. Image processing included three-dimensional volume renderings and multiplanar reformations. Two radiologists assessed the prevalence of vascular variants that were important for surgical planning and execution. RESULTS: We identified surgically important hepatic vascular variants in 70 (65%) of the 107 patients. A total of 129 variants were identified, of which 27 were important surgical considerations for recipients, 37 were important for donors, and 65 were important for both recipients (19 variants) and donors (46 variants). Of the 50 pairs of close relatives, 10 (20%) of the pairs were found to have the same hepatic vascular variant or one that was similar. However, when the pairs were set randomly, with no genetically related pairs included, similar variants were noted in 11 pairs (22%). The most common hepatic arterial variant in all candidates was an accessory right or left hepatic artery. The most common hepatic venous variant was an accessory right inferior hepatic vein. CONCLUSION: We observed a high prevalence of surgically important vascular variants in living adult candidates for living liver transplant donation and receipt. Because of the frequent occurrence, similar variants are to be expected among these sets of patients, regardless of whether they are closely related.     

Biliary tract depiction in living potential liver donors: comparison of conventional MR, mangafodipir trisodium-enhanced excretory MR, and multi-detector row CT cholangiography--initial experience

PURPOSE: To compare biliary tract depiction in living potential liver donors at conventional magnetic resonance (MR), mangafodipir trisodium-enhanced excretory MR, and multi-detector row computed tomographic (CT) cholangiography. MATERIALS AND METHODS: Eight living potential liver donors underwent iodipamide meglumine-enhanced CT cholangiography. Eight different potential liver donors then underwent conventional MR cholangiography and mangafodipir trisodium-enhanced excretory MR cholangiography. Two readers independently scored all first-, second-, and third-order biliary branches with a four-point scale from 0 (not seen) to 3 (excellent visualization). Interobserver agreement was calculated by using the weighted kappa statistic. Scores were compared between imaging modalities by using generalized estimating equations. Imaging findings of second-order biliary tract anatomy were compared with intraoperative findings for nine patients. RESULTS: Interobserver agreement for overall biliary tract visualization was good for CT, conventional MR, and excretory MR cholangiography (with weighted kappa values of 0.76, 0.66, and 0.79, respectively). The mean second-order biliary branch visualization scores for readers 1 and 2, respectively, were significantly higher at CT cholangiography (2.81 and 2.75) than at conventional MR (1.84 and 1.75, P <.001), excretory MR (2.00 and 2.06, P <.001), and combined conventional and excretory MR cholangiography (2.31 and 2.25, P <.01). At CT, conventional MR, and excretory MR cholangiography, respectively, second-order biliary branching anatomy was discernible in eight, five, and seven patients, with second-order biliary branch variants seen in three, two, and two patients. Surgical findings confirmed the pattern of second-order biliary branching seen at CT in five patients, that seen at conventional MR imaging in one patient, and that seen at excretory MR cholangiography in three patients. At surgery, one case of variant biliary anatomy was found to have been missed at CT cholangiography. CONCLUSION: In living potential liver donors, CT cholangiography enables significantly better biliary tract visualization than conventional or excretory MR cholangiography either alone or in combination.     

Multi-detector row helical CT angiography of hepatic vessels: depiction with dual-arterial phase acquisition during single breath hold

PURPOSE: To determine by using multi-detector row computed tomography (CT), in a triphasic hepatic dynamic study, which included single breath-hold dual-arterial phase acquisition, the accuracy and frequency of visualization of the small hepatic arterial and portal venous anatomy with angiographic correlation. MATERIALS AND METHODS: In 62 patients, pre- and postcontrast triphasic helical CT were performed by using a multi-detector row CT scanner, with 2.5-mm detector row collimation, at a pitch of 6. The first and second arterial phases were performed during a single breath hold. One reader, blinded to the results of the angiography, reviewed the first arterial phase images on a cine display to assess hepatic arterial anatomy. Visualization of the portal vein and its branches was assessed by using second arterial and portal venous phase images. RESULTS: Major arterial trunks (celiac, hepatic, superior mesenteric, and left gastric) were depicted in all cases. Visualization of small arteries was as follows: right and left hepatic, 62 (100%) of 62; middle hepatic, 52 (87%) of 60; cystic, 47 (90%) of 52; right gastric, 50 (89%) of 56; and right and left inferior phrenic, 57 (92%) and 55 (89%) of 62, respectively. Subsegmental or more peripheral branches of the portal vein were depicted in 83% of cases during the second arterial phase and in 96% during the portal phase. There was no difference in degree of visualization in these two phases. CONCLUSION: Multi-detector row CT angiography was able to depict the hepatic vascular anatomy.     

Assessment of 100 live potential renal donors for laparoscopic nephrectomy with multi-detector row helical CT

PURPOSE: To retrospectively review the authors' experience with multi-detector row helical computed tomography (CT) in assessing 100 consecutive live potential renal donors. MATERIALS AND METHODS: Hospital ethical committee approval was obtained; informed patient consent was not required. One hundred potential renal donors underwent multi-detector row CT assessment. Nonenhanced, arterial phase, and nephrographic phase examinations were performed. Delayed topograms were acquired to visualize the collecting system anatomy. A vascular radiologist prospectively interpreted the multi-detector row CT images. A second vascular radiologist, blinded to the initial results, retrospectively reviewed the images. Eighty candidates subsequently underwent donor nephrectomy, including 70 laparoscopic donor nephrectomies (LDNs) and 10 open donor nephrectomies (ODNs). Surgical findings served as the reference standard for 80 kidneys. The imaging findings in all 100 candidates (200 kidneys) were reviewed, although these findings were considered observational data only because there was no reference standard for 120 kidneys. RESULTS: Multi-detector row CT findings predicted uncomplicated LDN in 67 of 70 patients. Small upper-pole capsular arteries arising from the distal main renal artery in two patients were not described in the multi-detector row CT report: In one patient, the arising vessels resulted in conversion to ODN because of bleeding; in the other patient, arterial reconstruction was performed. In another patient, conversion to ODN was necessary because of ongoing bleeding from an avulsed large lumbar venous tributary to the left renal vein. Observational data revealed that multiple renal arteries--most of which were accessory renal arteries--were seen in 52 (26%) kidneys. Early branching of the main renal artery was seen in 24 (12%) kidneys, and main renal arterial abnormalities were identified in six (3%). Capsular arteries were detected in 10 (5%) kidneys. Major variations in the anatomy of the main renal veins--including multiple right renal veins, a retroaortic left renal vein, and a circumaortic left renal vein--were seen in 28 (14%) kidneys. Large (>5 mm in diameter) systemic tributaries to the left renal vein were seen in 25 (25%) kidneys. There was no significant interobserver disagreement between the vascular radiologists. CONCLUSION: Multi-detector row CT findings can predict successful LDN in live potential renal donors.     

Multidetector CT in pre- and post-operative evaluation of living-related liver transplantation

Objective

To assess the role of multi-detector CT (MDCT) in the pre and post operative evaluation of both potential donors and recipients for living related liver transplantation (LRLT).

Material and Methods

This prospective study included 26 patients for LRLT and their corresponding donors. For preoperative assessment, all subjects were evaluated by triphasic CT abdomen. CT angiography (CTA) with 3D reconstruction and CT volumetry was additionally done for donors. CT findings were compared to surgical results as gold standard reference. In post-operative evaluation, CT abdomen was performed at least once after transplantation for all recipients and for indicated donors. CTA was done for indicated recipients when US findings were inconclusive.

Results

No statistically significant difference was found between CT volumetry and intraoperative findings. Compared to surgical findings, MDCT identified hepatic arterial and portal venous anatomy with 100% sensitivity and specificity, while for hepatic venous anatomy; it showed sensitivity and specificity of 85.7% and 84.2%. Biliary complications and fluid collections were the commonest in recipients and donors respectively.

Conclusion

MDCT is a single comprehensive non-invasive and accurate imaging modality for preoperative evaluation of liver parenchyma, hepatic vascular anatomy and graft volume and postoperative complications in donors and recipients of LRLT.     

Multi-detector row CT of relevant vascular anatomy of the surgical plane in split-liver transplantation

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 >7 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.     

Hepatocellular carcinoma: role of unenhanced and delayed phase multi-detector row helical CT in patients with cirrhosis

PURPOSE: To determine, by using multi-detector row helical computed tomography (CT), the added value of obtaining unenhanced and delayed phase scans in addition to biphasic (hepatic arterial and portal venous phases) scans in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis. MATERIALS AND METHODS: Local ethical committee approval and patient consent were obtained. One hundred ninety-five patients (129 men, 66 women; mean age, 61 years; age range, 39-78 years) with 250 HCCs underwent multi-detector row helical CT of the liver. A quadruple-phase protocol that included unenhanced, hepatic arterial, portal venous, and delayed phases was performed. Analysis of images from hepatic arterial and portal venous phases combined, hepatic arterial and portal venous phases with the unenhanced phase, hepatic arterial and portal venous phases with the delayed phase, and all phases combined was performed separately by three independent radiologists. Relative sensitivity, positive predictive value, and area under the receiver operating characteristic curve (A(z)) were calculated for each reading session. RESULTS: Mean sensitivity and positive predictive values, respectively, for HCC detection were 88.8% (666 of 750 readings) and 97.8% (666 of 681 readings) for the combined hepatic arterial and portal venous phases, 89.2% (669 of 750 readings) and 97.8% (669 of 684 readings) for hepatic arterial and portal venous phases with the unenhanced phase, 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for hepatic arterial and portal venous phases with the delayed phase, and 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for all four phases combined. The reading sessions in which delayed phase images were available for interpretation showed significantly (P < .05) superior sensitivity and A(z) values. CONCLUSION: Unenhanced phase images are not effective for HCC detection. Because of the significant increase in HCC detection, a delayed phase can be a useful adjunct to biphasic CT in patients at risk for developing HCC.     

Multi--detector row helical CT of the pancreas: effect of contrast-enhanced multiphasic imaging on enhancement of the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma.

PURPOSE: To determine the optimal phase for enhancement of the normal pancreas and peripancreatic vasculature and the maximal tumor-to-pancreatic parenchymal enhancement difference by using multiphase, contrast material-enhanced, multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Forty-nine patients with a normal-appearing pancreas but suspected of having pancreatic abnormality and 28 patients with proved pancreatic adenocarcinoma underwent multiphase, contrast-enhanced, multi-detector row CT during the arterial phase (AP), pancreatic parenchymal phase (PPP), and portal venous phase (PVP). Attenuation values of the normal pancreas, pancreatic adenocarcinoma, celiac and superior mesenteric arteries, and superior mesenteric and portal veins were measured during all three imaging phases. Quantitative analysis of these measurements and subjective qualitative analysis of tumor conspicuity were performed. RESULTS: Maximal enhancement of the normal pancreatic parenchyma occurred during the PPP. Maximal tumor-to-parenchyma attenuation differences during the PPP and PVP were equivalent but greater than that during the AP. Subjective analysis revealed that tumor conspicuity during the PPP and PVP was equivalent but superior to that during the AP. Maximal arterial enhancement was seen during the PPP, and maximal venous enhancement was seen during the PVP. CONCLUSION: A combination of PPP and PVP imaging is sufficient for detection of pancreatic adenocarcinoma, because it provides maximal pancreatic parenchymal and peripancreatic vascular enhancement. AP imaging can be reserved for patients in whom CT angiography is required.     

Effects of TIPS on liver perfusion measured by dynamic CT

OBJECTIVE: Our aim was to measure the arterial, portal venous, and total perfusion of the liver parenchyma with dynamic, single-section CT in patients with liver cirrhosis before and after transjugular intrahepatic portosystemic shunt (TIPS) placement and to compare the results with normal values. SUBJECTS AND METHODS: Perfusion of the liver parenchyma was measured in 24 healthy volunteers and 41 patients with liver cirrhosis using dynamic single-section CT. Seventeen patients underwent TIPS placement, and CT measurements were repeated within 7 days. CT scans were obtained at a single level comprising the liver, spleen, aorta, and portal vein. Scans were obtained over a period of 88 sec (one baseline scan followed by 16 scans every 2 sec and eight scans every 7 sec) beginning with the injection of a contrast agent bolus (40 mL at 10 mL/sec). Parenchymal and vascular contrast enhancement was measured with regions of interest, and time-density curves were obtained. These data were processed with a pharmaco-dynamic fitting program (TopFit), and the arterial and portal venous component and the total perfusion of the hepatic parenchyma were calculated (milliliters of perfusion per minute per 100 mL of tissue). RESULTS: Mean normal values for hepatic arterial, portal venous, and total perfusion were 20, 102, and 122 mL/min per 100 mL, respectively. In patients with cirrhosis before TIPS, mean hepatic arterial, portal venous, and total perfusion was 28, 63, and 91 mL/min per 100 mL, respectively, which was statistically significant for all values (p <0.05). After TIPS, hepatic perfusion increased to a mean value of 48, 65, 113 mL/min per 100 mL for arterial (p <0.01), portal venous, and total (p=0.011) perfusion, respectively. CONCLUSION: In patients with cirrhosis, the hepatic arterial perfusion increased, whereas portal venous and total perfusion decreased compared with that of healthy volunteers. TIPS placement caused a statistically significant increase of the hepatic arterial and total hepatic perfusion. The portal venous parenchymal perfusion remained unchanged.     

Pre-operative hepatic vascular mapping of living donor for liver transplantation using 64-MDCT

Objective

The purpose of the present study was to assess the performance of 64-row MDCT angiography in the mapping of hepatic vascular anatomy in potential living liver donors with special attention paid to the anatomical variants, which influence the donor selection and surgical planning.

Material and Methods

Evaluation of 43 potential living donors was performed using 64-row MDCT scanner to obtain hepatic arterial and venous phases. Eleven subjects were excluded as they did not perform the transplantation surgery. The hepatic arterial (HA) anatomy was evaluated and classified according to Michel classification with special attention given to those considered relative or absolute contraindications for donation and those may alternating the surgical procedure. The origin and course of the artery to segment IV were determined. Portal venous (PV) anatomy was assessed and classified according to Cheng classification. Hepatic venous anatomy was evaluated with special attention paid to middle hepatic vein (MHV) anatomy, significant accessory branches crossing dissection line or that may require additional anastomosis.

Results

64-Row MDCT was done for 43 potential living donors. Eleven subjects were excluded as they did not perform the transplantation surgery. Thirty-two living donors for liver transplantation were enrolled in this study. Standard hepatic arterial anatomy was determined in 19 subjects (59.4%) while 13 candidates (40.6%) showed hepatic arterial variations. The replaced RHA arises from the SMA was the commonest (n = 5, 15.6%). The dominant artery to segment IV was a branch from the left hepatic artery (LHA) in 24 cases (75%) and from right hepatic artery in 8 cases (25%). Classic portal venous anatomy was found in 26 candidates (81.2%) while its variants were detected in 6 cases. Standard hepatic venous anatomy was found in 21 candidates (65.6%). A total of 11 subjects (34.4%) showed hepatic venous variants. 8 cases (25%) had single significant accessory hepatic vein while 3 subjects (9.4%) had two or more significant accessory hepatic veins. MHV confluence was late in 4 candidates (12.5%). An accessory inferior right hepatic vein was the commonest accessory hepatic vein that was detected in 7 cases (21.9%).Compared to surgical findings, MDCT correctly identified hepatic arterial and portal venous anatomy in all cases with no false positive or false negative cases. Sensitivity, specificity, PPV, NPV and accuracy of MDCT in identification of hepatic arterial and portal anatomy were all 100% while for hepatic venous anatomy, the corresponding values were 83.3%, 100%, 100%, 90.1% and 93.8%, respectively.

Conclusion

64-Row MDCT is an essential part of pre-operative evaluation of potential liver donors. It is a non-invasive comprehensive evaluation tool that can show the hepatic vascular anatomic details with precise relationship to liver parenchyma.     

Pancreatic malignancy: value of arterial, pancreatic, and hepatic phase imaging with multi-detector row CT

PURPOSE: To assess the value of arterial, pancreatic, and hepatic phase imaging at multi-detector row computed tomography (CT) of the pancreas for pancreatic malignancy. MATERIALS AND METHODS: Thirty-nine patients suspected of having resectable pancreatic adenocarcinoma underwent triple-phase multi-detector row CT. Images obtained during each phase were interpreted by one radiologist who evaluated presence of tumor, vascular invasion, and flow artifacts in the superior mesenteric vein and measured attenuation of tumor, normal pancreas, aorta, and superior mesenteric vein. Results were compared with histologic, follow-up, and correlative imaging findings. RESULTS: Mean tumor-to-gland attenuation difference was greatest on images obtained in the pancreatic phase (42 HU) versus that on those obtained in the hepatic phase (35 HU) and in the arterial phase (25 HU). For tumor detection, sensitivity of the images obtained in pancreatic (0.97 [29 of 30]) and hepatic (0.93 [28 of 30]) phases was superior to that of those obtained in arterial phase (0.63 [19 of 30]) (P < or =.008). For vascular invasion detection, sensitivity of images obtained in the hepatic phase (0.83) was better than that of those obtained in the pancreatic (0.58) and arterial (0.25) phases. Images obtained in the pancreatic phase demonstrated more flow artifacts and decreased attenuation in the superior mesenteric vein, compared with the artifacts revealed on images obtained in the hepatic phase. CONCLUSION: Routine acquisition of images in the arterial phase is unnecessary for detection of pancreatic adenocarcinoma. Images of the pancreas obtained in the hepatic phase with multi-detector row CT most accurately display vascular invasion.     

Hepatic involvement in hereditary hemorrhagic telangiectasia: helical computed tomography features in 24 consecutive patients

OBJECTIVE: Among the various organs that may be affected by hereditary hemorrhagic telangiectasia (HHT), the liver can show various degrees of vascular and parenchymal involvement. The purpose of this prospective study comprising a large series of patients was to reassess the computed tomography (CT) features of hepatic involvement in HHT using helical CT. METHODS: Twenty-four consecutive patients with HHT had prospective helical CT of the liver, including noncontrast, arterial-dominant, and portal-dominant phases. The CT images were analyzed by 2 readers in consensus to determine the presence of vascular and parenchymal abnormalities. The diameter of the proper hepatic artery in these 24 patients was compared with that in 24 healthy subjects (Student t test). RESULTS: Helical CT was normal in 5 patients (21%) and abnormal in 19 patients (79%). Vascular abnormalities were found in 16 patients (67%), consisting of marked dilatation of the hepatic artery (n = 16), intrahepatic telangiectases (n = 12), arteriovenous shunting (n = 5), and arterioportal shunting (n=3). The diameter of the proper hepatic artery was greater in the patients with HHT than in control subjects (6.12 +/- 2.52 mm vs. 3.29 +/- 0.65 mm, respectively; P < 0.05). Helical CT showed nodular hyperplasia in 1 patient with vascular and parenchymal abnormalities, cavernous hemangiomas in 2 patients (1 in a patient with an enlarged hepatic artery, intrahepatic telangiectases, and arteriovenous shunting and 1 in a patient with an isolated enlarged hepatic artery), and biliary cysts in 3 patients (2 biliary cysts were present in 2 patients with an enlarged hepatic artery and intrahepatic telangiectases, and 1 biliary cyst was present without any manifestations in the third patient). CONCLUSION: Liver involvement in HHT is associated with a constellation of findings on helical CT, including significant dilatation of the proper hepatic artery, telangiectases, arteriovenous shunting, and focal liver lesions. Familiarity with these findings will result in more accurate diagnosis and allows better therapeutic options if necessary.