H.-W. Hsu

Magnetic resonance cholangiography in living donor liver transplantation.

Objective. Exact knowledge of biliary anatomy is essential in living donor liver transplantation. The purpose of this study was to evaluate the accuracy of pretransplant magnetic resonance cholangiography (MRC) in depicting the biliary anatomy in comparison with intraoperative cholangiography (IOC). Materials and Methods. From May 2006 to July 2009, 451 potential living liver donors underwent pretransplant evaluation at the Chang Gung Memorial Hospital–Kaohsiung Medical Center. Two hundred thirty-three donors underwent donor hepatectomy. Of these, only 203 donors with both preoperative MRC and IOC were included in this study. Results. Of the 451 potential donors, 218 (48.3%) were considered unsuitable for liver donation, hence was immediately disqualified after the initial evaluation for various reasons. Six of the 218 unsuitable donors (2.8%) were excluded due to complicated biliary anatomy. The overall accuracy rate of MRC for defining the biliary anatomy was 91.6%, with 84.9% sensitivity, 96% specificity, 88.2% positive predictive value, and 94.7% negative predictive value. There were 14 misidentified cases. The errors in MRC reading was largely attributed to the poor contrast between the biliary ducts and the surrounding tissues and organs. The concurrence between MRC and IOC were commendable (&kgr;=0.9). No significant biliary complications were noted in the mismatch group. Conclusion. MRC is essential for all pretransplantation evaluation with 91.6% accuracy rate.

The Acoustic Radiation Force Impulse Elastography Evaluation of Liver Fibrosis in Posttransplantation Dysfunction of Living Donor Liver Transplantation

BACKGROUNDnThe acoustic radiation force impulse elastography (ARFI) is a new technology of elastography integrated into B-mode ultrasonography. It has been a reliable method to evaluate liver fibrosis of chronic liver disease in recent years, but less applied in the posttransplantation liver. The aim of the study was to evaluate liver fibrosis by the ARFI with correlation of pathological stages in living donor liver transplantation (LDLT).nnnMATERIALS AND METHODSnFrom August 2010 to August 2012, there were 57 LDLT patients with liver biopsy (LB) due to posttransplantation dysfunction; all patients also received posttransplantation ARFI liver stiffness measurement (LSM) after transplantation for liver fibrosis staging. The ARFI elastography was performed using a Siemens Acuson S2000 ultrasound system with 4V1 transducers (Acusion, Siemens Medical Systems Co. Ltd. Erlangen, Germany). The ARFI LSM value was presented by shear wave velocity (SWV, m/s). The fibrosis staging as F0 to F4 was in accordance with the Metavir scoring system.nnnRESULTSnA total of 57 patients had both posttransplantation LB and effective ARFI fibrosis staging for correlation. The ARFI LSM value increased with severity of liver fibrosis and had significant linear correlation with the results of histological fibrosis staging. The ARFI LSM sensitivities (Se), specificities (Sp), and cutoff values based on receiver-operator characteristic curve were F0: 0.75 m/s (Se: 93.8%, Sp: 4%), F1: 1.06 m/s (Se: 95.5%, Sp: 25.7%), F2: 1.81 m/s (Se: 50%, Sp: 83.6%) and F3: 2.33 m/s (Se: 100%, Sp: 92.9%). Predictive value of ARFI LSM reported a significant difference between early fibrosis stage (F0-F1) and advanced fibrosis stage (F ≧ 2) (Pxa0< .05).nnnCONCLUSIONnIn this study, ARFI demonstrated a strong linear correlation and severity of liver fibrosis with LB pathologic staging. ARFI can be an alternative and compensatory method for frequent LB in the posttransplantation liver.

Magnetic Resonance Cholangiography in Living Donor Liver Transplantation: Comparison of Preenhanced and Post-Gadolinium-Enhanced Methods

OBJECTIVEnThe purpose of this study was to evaluate the image quality and diagnostic accuracy of postgadolinium complex of diethylenetriaminepentaacetic acid (GD-DTPA)-enhanced magnetic resonance cholangiography (MRC) in donor selection.nnnMATERIALS AND METHODSnDonors (n=228) with both preoperative MRC and intraoperative cholangiography (IOC) were enrolled in this study. MRC pre- and post-GD-DTPA enhancement were performed using 1.5-T magnetic resonance imaging. The signal-to-noise ratio (SNR) of liver parenchyma and contrast-to-noise ratio of bile duct, as well as the contrast between bile duct and liver parenchyma, were calculated. The biliary anatomy correlation with the IOC during hepatectomy and patient prognosis were also evaluated.nnnRESULTSnQuantitative results of the SNR of the liver parenchyma post-GD-DTPA were statistically significantly lower than preenhanced MRC (2.69 times reduced from the preenhanced MRC). The contrast of the bile duct and liver parenchyma in post-GD-DTPA were significantly higher than the preenhancement MRC. The anatomic diagnostic accuracy rate of post-GD-DTPA MRC was 92.9%. The sensitivity and specificity of GD-PTPA MRC were 85% and 96%, respectively. GD-DTPA-enhanced MRC has higher accuracy than the preenhanced MRC (92.9% vs 75%). The concurrence between GD-DTPA-enhanced MRC and IOC were commendable (kappa=0.9). The posttransplant biliary complication rate was 5.5%, and the 3-year survival rate was 91.2% in the recipients.nnnCONCLUSIONnGD-DTPA, a paramagnetic metal, can shorten the T1 and T2 relaxation values of surrounding protons. This decreases the signal of the liver parenchyma and brightens the biliary anatomy. It can improve the image quality of MRC and increase the diagnostic accuracy of the biliary tract classification. It is mandatory in the donor and recipient surgery during the LDLT.

Interventional radiology in living donor liver transplant

The shortage of deceased donor liver grafts led to the use of living donor liver transplant (LDLT). Patients who undergo LDLT have a higher risk of complications than those who undergo deceased donor liver transplantation (LT). Interventional radiology has acquired a key role in every LT program by treating the majority of vascular and non-vascular post-transplant complications, improving graft and patient survival and avoiding, in the majority of cases, surgical revision and/or re-transplant. The aim of this paper is to review indications, diagnostic modalities, technical considerations, achievements and potential complications of interventional radiology procedures after LDLT.

Predictive Factors for Persistent Splenomegaly and Hypersplenism After Adult Living Donor Liver Transplantation

PURPOSEnThe aim of this study was to evaluate predictive factors for persistent splenomegaly and hypersplenism after living donor liver transplantation (LDLT).nnnPATIENTS AND METHODSnFrom January 2008 to June 2010, 159 adult patients (116 males and 43 females) who underwent living donor liver transplantation (LDLT) had pre- and post-LDLT computed tomography angiography and survived more than 6 months. Patients with post-LDLT portal vein stenosis were excluded from this study. We analyzed the impact for persistent splenomegaly and hypersplenism after LDLT of pre-LDLT spleen volume, main portal vein (PV) size, coronary vein (CV) size and platelet levels.nnnRESULTSnWhile 38 patients displayed splenomegaly, 121 showed normal spleen volumes at 6 months after LDLT (LDLT). There were 119 thrombocytopenic versus 40 normal platelet patients at 6 months post-LDLT. The persistent splenomegaly patients showed significantly larger pre-LDLT spleen volume, larger PV and CV sizes as well as lower platelet levels before (×10,000/mL) and 1 month after LDLT (×10,000/mL). Multiple logistic regression analysis showed spleen volume and platelet count at 1 month posttransplant to be the only variables associated with persistent splenomegaly at 6 months post. Persistent thrombocytopenia at 6 months post-LDLT was associated with significantly larger pre-LDLT spleen volume, larger CV size, and lower platelet levels including P0 and P1 m. Multiple logistic regression analysis showed that platelet count at 1 week and at 1 month post-LDLT were the variables associated with persistent thrombocytopenia at 6 months post-LDLT.nnnCONCLUSIONnSpleen volume and platelet levels at 1 month after LDLT may predict persistent splenomegaly at 6 months post-LDLT. The predictive factors for hypersplenism at 6 months post-LDLT may be platelet levels at 1 week and at 1 month post-LDLT.

Combined Hepatocellular Carcinoma and Cholangiocarcinoma: Diagnosis and Prognosis After Resection or Transplantation

BACKGROUNDnPrimary liver malignancy is the leading cause of cancer death worldwide, with hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) representing the majority. Combined HCC-CC, in contrast, accounts for less than 5% of these liver cancers and has not been clearly characterized by imaging, making diagnosis and management difficult.nnnMATERIALS AND METHODSnThis retrospective study investigated 32 patients with early-stage combined HCC-CC tumor who underwent hepatectomy (nxa0= 24) or liver transplantation (nxa0= 8). Preoperative imaging and pathologic reports were retrospectively reviewed and correlated. Survival and recurrence rates were then analyzed.nnnRESULTSnTwelve patients with more than 50% CC component showed typical CC enhancement, whereas 17 patients with less than 50% CC component exhibited typical HCC enhancement. Those with equivocal imaging findings resulted near equal tumor component. The majority demonstrated either heterogeneous or peripheral enhancement. Considering the major tumor component, 66% of the images were consistent with histopathology. The over-all 3-year recurrent rate was 59%, with a mean time to recurrence of about 7 months. The 3-year survival rate of combined tumor after hepatectomy was 76% and after transplant was 75%, regardless of major tumor component. However, patients with more than 50% CC component showed a decrease in 3-year survival rate to 50% when transplantation was performed.nnnCONCLUSIONnThe overall survival rate for combined tumor after either hepatectomy or transplantation seems to be satisfactory but carries a high risk of recurrent when compared to pure HCC. On the other hand, a major CC component tumor after transplantation is associated with poor survival outcome; thus, liver transplantation has no role and is not a good management option.

Graft Regeneration in Pediatric Living Donor Liver Transplantation

OBJECTIVEnDue to the shortage of cadaver liver grafts in Asia, more than 90% of biliary atresia (BA) patients require living donor liver transplantation (LDLT), but the factors that influence liver graft regeneration in pediatric patients are still unclear. The aim of this study was to evaluate the potential predisposing factors that encourage liver graft regeneration in pediatric liver transplantation (LT).nnnMETHODSnCase notes and Doppler ultrasound and computed tomography studies performed before and 6 months after transplantation of 103 BA patients who underwent LDLT were reviewed. The predisposing factors that triggered liver regeneration were compiled from statistical analyses and included the following: age, gender, body weight and height, spleen size, graft weight-to-recipient weight ratio (GRWR), post-transplantation total portal flow, and vascular complications.nnnRESULTSnSeventy-two pediatric recipients were enrolled in this study. The liver graft regeneration rate was 29.633 ± 36.61% (range,xa0-29.53-126.27%). The size of the spleen (Pxa0= .001), post-transplantation portal flow (Pxa0= .004), and age (Pxa0= .04) were correlated lineally with the regeneration rate. The GRWR was negatively correlated with the regeneration rate (Pxa0= .001) and was the only independent factor that affected the regeneration rate. When the GRWR was >3.4, patients tended to have poor and negative graft regeneration (Pxa0= .01).nnnCONCLUSIONnLarge-for-size grafts have negative effect on regeneration rates because liver grafts that are too large can compromise total portal flow and increase vascular complications, especially when the GRWR is >3.4. Thus, optimal graft size is more essential than other factors in a pediatric LDLT patient.

Noncontrast Magnetic Resonance Angiography Using Inflow Sensitive Inversion Recovery Technique for Vascular Evaluation in Pre–liver Transplantation Recipients

OBJECTIVEnVascular anatomy is essential in pretransplantation survey. The purpose of this study is to investigate the feasibility and diagnostic performance of inflow sensitive inversion recovery (IFIR) magnetic resonance angiography (MRA) to evaluate the recipients hepatic vasculature before liver transplantation.nnnMATERIALS AND METHODSnThirty-one pre-liver transplantation patients underwent both IFIR and conventional contrast-enhanced MRA using a 1.5T MR scanner from December 2012 to December 2014. The contrast-to-noise ratios (CNRs) between liver parenchyma and hepatic vasculature were calculated. The image sets of IFIR and contrast-enhanced MRA were assessed for subjective image quality and depiction of hepatic vasculature on vessel-to-vessel basis by two independent radiologists.nnnRESULTSnThe quantitative results of CNR for hepatic arteries on IFIR were significantly lower than contrast-enhanced MRA, whereas CNR for portal veins and inferior vena cava on IFIR were significantly higher than contrast-enhanced MRA. For subjective assessment of image quality, the overall agreement of scores of IFIR and contrast-enhanced MRA was substantial (kappa values ranged from 0.650 to 0.767). There was no significant difference in the image quality for portal veins between IFIR and contrast-enhanced MRA. The quality scores of IFIR were significantly lower than contrast-enhanced MRA for hepatic arteries. For inferior vena cava evaluation, the scores of IFIR were significantly higher than contrast-enhanced MRA.nnnCONCLUSIONnIFIR MRA is a reproducible and noninvasive tool to assess the hepatic vasculature that can provide adequate to good image quality. In pre-liver transplantation patients, IFIR MRA becomes even more useful if contrast medium is a contraindication due to impaired renal and liver functions.

Sonographic Evaluation of Post-transplantation Portal Vein Stenosis in Pediatric Living-donor Liver Transplant Recipients With Left-liver Grafts

INTRODUCTIONnPortal vein (PV) stenosis is not uncommon in post-transplantation pediatric living-donor liver transplant (PLDLT) recipients. The purpose of this study was to identify specific ultrasound criteria that may be used to detect PV stenosis in PLDLT with left-liver grafts.nnnPATIENTS AND METHODSnFrom January 2010 to October 2014, 87 pediatric recipients underwent PLDLT with left lobes or left lateral segments at our hospital. All patients underwent routine liver Doppler ultrasound (DUS) as follow-up protocol. The morphologic narrowing and mean time averaged velocity (TAV) at the PV anastomotic site, change inxa0anastomotic/pre-anastomotic TAV (ΔTAV), and the umbilical portal width were evaluated and analyzed. Ultrasound findings were correlated with computed tomography angiography where PV stenosis was suspected.nnnRESULTSnIn the liver graft follow-up study, 80.4% (70 of 87 patients) of PV anastomosis was well visualized and measured by Doppler ultrasound. The optimal threshold values for TAV and ΔTAV were 49.6xa0cm/s and 30xa0cm/s, respectively, for significant PV anastomosis stenosis. In the other 19.5% (17/87), the PV anastomosis could not be identified properly. The PV anastomosis was not always visible with ultrasound; however, the optimal dilated umbilical portion of the PV indicating possible PV anastomosis narrowing threshold was umbilical portal width >1.5xa0cm.nnnCONCLUSIONSnIncreased anastomotic TAV and ΔTAV are useful features for diagnosing PV stenosis. The identification of a dilated umbilical portion of the left PV helps in detection of PV stenosis in PLDLT recipients especially when the anastomotic narrowed region cannot be visualized.

Portal venous pressure in adult living donor liver transplantation.

OBJECTIVEnThe relationship between portal pressure and small-for-size syndrome (SFSS) is unsettled. The purpose of this study was to evaluate the role of portal pressure in predicting SFSS.nnnMETHODSnThirty-four patients with end-stage liver disease who received adult-to-adult living-donor liver transplantation (ALDLT) were included. Recipients were grouped based on whether they received portal flow modulation or not. The intraoperative portal vein flow volume (PVFV) and portal venous pressure (PVP) between the 2 groups were compared. The relationship of PVP to PVFV, graft weight-to-recipient weight ratio (GRWR), and graft weight-to-recipient spleen size ratio (GRSSR) were analyzed.nnnRESULTSnPersistent portal hypertension was found after ALDLT. The PVP was linearly correlated with PVFV but not with GRWR or GRSSR. With the use of the following criteria, (1) PVFV >250 mL/min/100 g graft weight, (2) GRWRxa0<0.8%, and (3) GRSSRxa0<0.6, modulation of the portal flow was performed in 3 cases. The receiver operating characteristic analysis showed that 23 mm Hg was the cutoff point for PVP, with a sensitivity of 83% and specificity of 43%.nnnCONCLUSIONSnPVP is a weak parameter to use for portal flow modulation after ALDLT. It is sensitive but not specific to predict SFSS.