Tobias Schroeder

Detection of pulmonary nodules using a 2D HASTE MR sequence: comparison with MDCT

OBJECTIVE The objective of our study was to determine the diagnostic performance of MRI based on a HASTE sequence for the detection of pulmonary nodules in comparison with MDCT. MATERIALS AND METHODS Thirty patients with known pulmonary nodules underwent both MRI and CT. CT of the lung served as the standard of reference and was performed on a 4-MDCT scanner using a routine protocol. MRI was performed with axial and coronal HASTE sequences using a high-performance 1.5-T MR scanner. Image data were analyzed in three steps after completion of all data acquisition. Step 1 was the analysis of all the CT image data. Step 2 was the analysis of all the MR image data while blinded to the results of the CT findings. Step 3 closed with a simultaneous review of all corresponding CT and MRI data, including a one-to-one correlation of the size and location of all the nodules that were detected. RESULTS Compared with the sensitivity of CT, the sensitivity values for the HASTE MR sequence were as follows: 73% for lesions less than 3 mm, 86.3% for lesions between 3 and 5 mm, 95.7% for lesions between 6 and 10 mm, and 100% for lesions larger than 10 mm. The overall sensitivity of the HASTE sequence for the detection of all pulmonary lesions was 85.4%. CONCLUSION An MRI examination that consists of a HASTE sequence allows one to detect, exclude, or monitor pulmonary lesions that are 5 mm and bigger. Suspicious lesions smaller than 5 mm still need to be validated using CT.

Multidetector computed tomographic cholangiography in the evaluation of potential living liver donors.

Background. Lacking awareness of biliary variations causes complications in adult living donor liver transplantation. The study was performed to determine the diagnostic value of preoperative multidetector computed tomographic cholangiography (MDCT-CA). Methods. MDCT-CA after the intravenous administration of meglumine iodipamide was performed in 12 potential liver donors. MDCT angiography was added to depict the topographic relationship between biliary and vascular structures. MDCT findings were correlated with intraoperative findings (n=7). Results. MDCT-CA was diagnostic in all 12 patients. Nine patients revealed variants in biliary anatomy: drainage from liver segment four into right hepatic duct (n=4), additional segmental ducts draining into common (n=4) or left hepatic duct (n=2), and trifurcation at the upper confluence (n=1). Biliary vascular topography was variable and well depicted. Intraoperative assessment confirmed the preoperative findings. Conclusions. Variations in biliary anatomy appear to be the rule rather than the exception. MDCT-CA represents a noninvasive means for accurately assessing biliary morphology.

CT-Guided Biopsy of Small Liver Lesions: Visibility, Artifacts, and Corresponding Diagnostic Accuracy

PurposeOur study aimed to determine the visibility of small liver lesions during CT-guided biopsy and to assess the influence of lesion visibility on biopsy results.Material and MethodsFifty patients underwent CT-guided core biopsy of small focal liver lesions (maximum diameter, 3 cm); 38 biopsies were performed using noncontrast CT, and the remaining 12 were contrast-enhanced. Visibility of all lesions was graded on a 4-point-scale (0 = not visible, 1 = poorly visible, 2 = sufficiently visible, 3 = excellently visible) before and during biopsy (with the needle placed adjacent to and within the target lesion).ResultsForty-three biopsies (86%) yielded diagnostic results, and seven biopsies were false-negative. In noncontrast biopsies, the rate of insufficiently visualized lesions (grades 0–1) increased significantly during the procedure, from 10.5% to 44.7%, due to needle artifacts. This resulted in more (17.6%) false-negative biopsy results compared to lesions with good visualization (4.8%), although this difference lacks statistical significance. Visualization impairment appeared more often with an intercostal or subcostal vs. an epigastric access and with a subcapsular vs. a central lesion location, respectively. With contrast-enhanced biopsy the visibility of hepatic lesions was only temporarily improved, with a risk of complete obscuration in the late phase.ConclusionIn conclusion, visibility of small liver lesions diminished significantly during CT-guided biopsy due to needle artifacts, with a fourfold increased rate of insufficiently visualized lesions and of false-negative histological results. Contrast enhancement did not reveal better results.

Computer-assisted surgical planning in adult-to-adult live donor liver transplantation: how much does it help? A single center experience.

Background Preoperative imaging and donor selection are cardinal components of adult-to-adult live donor liver transplantation (ALDLT). The purpose of this study was to evaluate our three-dimensional (3D) computed tomography image-derived computer-assisted surgical planning (3D CASP) in ALDLT. Methods Eighty-three consecutive ALDLTs (71 right and 12 left) were planned with 3D CASP. Graft, remnant, and total liver volume compliance were calculated and compared with actual intraoperative values. Computed risk analysis encompassing territorial liver mapping, functional (safely drained) volumes, and outflow congestion volumes in grafts and remnants allowed for the individualized management of the middle hepatic vein (MHV). Results Graft volume compliance was 13.5%±4.4%. Three small-for-size (SFS) grafts with lethal SFS syndrome (SFSS) had nonsignificant volume compliance with maximal graft volume-body weight ratios of less than 0.83. Seven SFS grafts with reversible or absent SFSS showed maximal graft volume-body weight ratios of 0.9 to 1.16. Significant differences were identified for (a) virtual graft and remnant congestion volumes of risky versus nonrisky MHV types (49%±6% and 34%±7% vs. 29%±8% and 33%±12%, P<0.001 and P<0.02, respectively) and (b) virtual mean functional versus surgical volumes of grafts (527±119 vs. 963±176 mL, P<0.0001) and remnants (419±182 vs. 640±213 mL, P<0.001). Conclusions CASP allowed for (a) prevention of SFSS in extremely small grafts by predicting donor liver plasticity and (b) individualized MHV management for both donors and recipients based on functional graft/remnant volume analysis.

Formation of Venous Collaterals and Regeneration in the Donor Remnant Liver: Volumetric Analysis and Three-Dimensional Visualization

PURPOSE We sought was to quantify and visualize the regeneration of the remnant liver after living donor liver transplantation using computed tomographic (CT) data. METHODS For the evaluation of preoperative and follow-up data, we developed a software assistant that was able to compute the volume growth of the remnant liver and liver territories as well as visualize the individual growth of hepatic vessels over time. The software was applied to CT data of 20 donors who underwent right hepatectomy including the middle hepatic vein with at least 3 follow-up examinations in the first year after transplantation. RESULTS After donation of a right lobe graft, the remnant liver regenerated by an average 77% of the original volume within the first 3 postoperative months and to 86% within the first year. The growth of the left lateral segments was increased compared with that of segment IV in all cases. The visualization showed the growth of the portal vein and the hepatic veins. With the simultaneous display of pre- and postoperative results, it was possible to detect the formation of collaterals between truncated segment IVb veins and the veins of segment IVa or of the left lateral lobe. CONCLUSION The software-assisted analysis of follow-up data yielded additional insight into territorial liver regeneration after living donor liver transplantation and allowed for reliable detection of relevant hepatic vein collaterals using CT data.

Changes in staging for hepatocellular carcinoma after radiofrequency ablation prior to liver transplantation as found in the explanted liver

BACKGROUND/AIMS To analyze the efficacy of radiofrequency ablation (RFA) prior to liver transplantation (LT) in liver explants. METHODOLOGY We reviewed pathological findings in the explanted livers of 13 patients with histologically proven HCC and liver cirrhosis who underwent RFA as bridging treatment prior to LT. Eight patients had solitary nodules with a median diameter of 4cm, whereas five patients had two tumors each with a median total diameter of 3.3cm prior to RFA. One session of RFA was performed by all patients. RESULTS Tumor regression was proved in 3/13 patients whereas steady disease was observed in 5/13 patients (38%). Tumor regression was observed only in one of the five patients having two tumors prior to RFA. Pathology proved a multifocal tumor in four patients, including one patient with a radiological presumed solitary tumor. Tumor progression was observed in 5/13 patients (38%). CONCLUSIONS Although the majority of our patients (8/13, 62%) had a solitary tumor at the beginning of treatment, tumor progression was observed in a large proportion (38%) among them. The underestimation of tumor lesions in radiology and partial necrosis of the tumor achieved in most patients limit the role of RFA as bridging treatment prior to LT.

Intrahepatic Biliary Anatomy Derived From Right Graft Adult Live Donor Liver Transplantation

OBJECTIVE The successful management of the bile duct in right graft adult live donor liver transplantation requires knowledge of both its central (hilar) and distal (sectorial) anatomy. The purpose of this study was to provide a systematic classification of its branching patterns to enhance clinical decision-making. PATIENTS AND METHODS We analyzed three-dimensional computed tomography (3-D CT) imaging reconstructions of 139 potential live liver donors evaluated at our institution between January 2003 and June 2007. RESULTS Fifty-four (n = 54 or 38.8%) donor candidates had a normal (classic) hilar and sectorial right bile duct anatomy (type I). Seventy-eight (n = 78 or 56.1%) cases had either hilar or sectorial branching abnormalities (types II or III). Seven (n = 7 or 5.1%) livers had a mixed type (IV) of a rare and complex central and distal anatomy. CONCLUSIONS We believe that the classification proposed herein can aid in the better organization and categorization of the variants encountered within the right-sided intrahepatic biliary system.

Anatomical Classification of the Peripheral Right Hepatic Duct: Early Identification of a Preventable Source of Morbidity and Mortality in Adult Live Donor Liver Transplantation

INTRODUCTION The purpose of this study was to determine the impact of our classification on right graft adult live donor liver transplantation (ALDLT) outcomes. METHODS Three-dimensional computed tomography (CT) reconstructions were used to classify the hilar and sectorial biliary anatomy of 71 consecutive live liver donors. Four possible clinical types were defined, based on the normal (N) or abnormal (A) features of the corresponding hilar/sectorial ducts: type I, N/N; type II, N/A; type III, A/N; and type IV, A/A. We subsequently performed an analysis of the operative outcomes based on the donor anatomy. RESULTS Type I was encountered in 47.9% of cases, type II in 29.6%, type III in 19.7%, and type IV in 2.8%. The highest incidence of biliodigestive anastomoses was observed with type III (50%) and type IV (100%) variants. Type I was associated with the highest incidence of single anastomoses (single vs multiple, P = .001) and of single bile duct anastomoses (single vs multiple, P = .004). Type III was associated with more multi-duct reconstructions compared with types I and II (P = .002 and P = .05, respectively). There were no significant differences in early (P = .08) or late (P = .33) biliary complications, or deaths due to a biliary etiology (P = .55) among the 4 types. CONCLUSIONS Complex biliary anatomy in the right liver graft usually requires biliodigestive anastomoses, which are often associated with complicated procedures. The precise delineation of the intrahepatic biliary anatomy provided by our clinical classification may contribute to better morbidity and mortality rates, especially for grafts at greatest anatomical risk.