Additional values of high-resolution gadoxetic acid-enhanced MR cholangiography for evaluating the biliary anatomy of living liver donors: Comparison with T 2 -weighted MR cholangiography and conventional gadoxetic acid-enhanced MR cholangiography

Propensity Score-matched Donor and Recipient Outcomes: Robotic Versus Laparoscopic Donor Right Hepatectomy

BACKGROUND

Few studies have examined the long-term outcomes of recipients in minimally invasive donor hepatectomies, particularly comparing robotic and laparoscopic donor procedures. Understanding these outcomes is crucial for optimizing surgical approaches and improving the overall success of living donor liver transplantation. This study aimed to compare the feasibility and safety of robotic donor right hepatectomy (RDRH) and laparoscopic donor right hepatectomy (LDRH) by evaluating total follow-up patient outcomes.

METHODS

This retrospective, single-center study included 117 and 118 donors who underwent RDRH and LDRH between March 2016 and June 2023, respectively. After performing 1:1 propensity score matching, 71 donor-recipient pairs were included in each group. Donor and recipient complications were divided into early (within 90 d) and late (after 90 d) biliary and vascular complications.

RESULTS

In the matched cohort, major complication rates of donors were similar in both groups. Bile duct (BD) variation was not significantly different; however, the rates of multiple BD openings (26.8% versus 54.9%; P  =   0.001) and major biliary complications in recipients were higher in the LDRH group (22.5% versus 42.3%; P  =   0.012). The cumulative biliary complication rate was significantly higher in the LDRH group. Early biliary complications were not significantly different; however, the rate of late biliary complications was higher in the LDRH group (11.3% versus 23.9%; P  =   0.047).

CONCLUSIONS

RDRH demonstrated comparable postoperative complications to LDRH in donors but showed fewer recipient biliary complications. This could be attributed to the precision of robotic dissection and BD division, resulting in fewer multiple BD openings.

Contrast-Enhanced T1-Weighted Magnetic Resonance Cholangiography Using Gadoxetate Disodium in Potential Living Liver Donors: Qualitative and Quantitative Improvement with 3-hour Delayed Imaging

BACKGROUND

Contrast-enhanced T1-weighted magnetic resonance cholangiography (CE-T1-MRC) after gadoxetate disodium administration can be used for preoperative evaluation of the bile ducts in live liver donors. This study aimed to determine whether CE-T1-MRC with 3-hour delayed imaging improves bile duct visualization both qualitatively and quantitatively compared with 20-minute delayed imaging in potential living liver donors.

METHODS

We retrospectively identified 33 potential living liver donors (mean age, 30.1 years; 18 men and 15 women) who underwent preoperative CE-T1-MRC with both 20-minute delayed and 3-hour delayed imaging in a single session. The radiologist scored biliary visualization for right and left hepatic ducts (RHD and LHD), their secondary confluences and segmental bile ducts, common hepatic duct (CHD), and cystic duct (CD), and measured relative contrast ratio (rC) and relative signal intensity (rS) for RHD, LHD, and CHD. The data were analyzed using Wilcoxon's signed-rank test and paired t-test.

RESULTS

In qualitative analysis, duct visualization scores for RHD and LHD, their secondary confluences and segmental bile ducts, CHD, and CD were significantly higher on CE-T1-MRC with 3-hour delayed imaging than with 20-minute delayed imaging (all, P ≤ .046). In quantitative analysis, both rC and rS of RHD, LHD, and CHD were significantly higher on CE-T1-MRC with 3-hour delayed imaging than with 20-minute delayed imaging (all, P < .001).

CONCLUSIONS

CE-T1-MRC with 3-hour delay imaging improves bile duct visualization both qualitatively and quantitatively in potential living liver donors.

Breath-hold High-resolution T1-weighted Gradient Echo Liver MR Imaging with Compressed Sensing Obtained during the Gadoxetic Acid-enhanced Hepatobiliary Phase: Image Quality and Lesion Visibility Compared with a Standard T1-weighted Sequence

PURPOSE

To evaluate the feasibility of breath-hold (BH) high-resolution (HR) T1-weighted gradient echo hepatobiliary phase (HBP) imaging using compressed sensing (CS) in gadoxetic acid-enhanced liver MRI in comparison with standard HBP imaging using parallel imaging (PI).

METHODS

The study included 122 patients with liver tumors with hypointensity in the HBP who underwent both HR HBP imaging with CS and standard HBP imaging with PI. Two radiologists evaluated the liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, image noise, and overall image quality, as well as the lesion conspicuity on HR and standard HBP imaging and the contrast-enhanced (CE) MR cholangiography (MRC) image quality reconstructed from HBP images. As a quantitative analysis, the SNR of the liver and the liver to lesion signal intensity ratio (LLSIR) were also determined.

RESULTS

The liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, and overall image quality as well as the lesion conspicuity and the LLSIR on HR HBP imaging with CS were significantly higher than those on standard HBP imaging (all of P < 0.001). The image quality of CE-MRC reconstructed from HR HBP imaging with CS was also significantly higher than that from standard HBP imaging (P < 0.001). Conversely, the SNR of liver in standard HBP was significantly higher than that in HR HBP with CS (P < 0.001).

CONCLUSION

BH HR HBP imaging with CS provided an improved overall image quality, lesion conspicuity, and CE-MRC visualization when compared with standard HBP imaging without extending the acquisition time.

High-resolution MR imaging with gadoxetate disodium for the comprehensive evaluation of potential living liver donors

OBJECTIVE

Several major transplantation centers have used composite multimodality evaluation for the preoperative evaluation of potential living liver donors. This approach can be time-consuming and, although rare, can cause complications. We aimed to demonstrate the clinical feasibility of our comprehensive preoperative MR protocol for the preoperative assessment of living liver donor candidates instead of composite multimodality evaluation.

MATERIALS AND METHODS

Thirty-five consecutive living liver donor candidates underwent multiphasic liver CT and comprehensive donor protocol MR examinations for preoperative evaluation in a single large-volume liver transplantation (LT) center. Three blinded abdominal radiologists reviewed the CT and MR images for vascular and biliary variations. The strength of agreement between CT and MR angiography was assessed using the kappa index. The detection rate of biliary anatomical variations was calculated. The sensitivity and specificity for detecting significant steatosis (>5%) were calculated. The estimated total volume and right lobe volumes measured by MR volumetry were compared with the corresponding CT volumetry measurements using the intraclass correlation coefficient (ICC).

RESULTS

Among the 35 patients, 26 underwent LT. The measurement of agreement showed a moderate to substantial agreement between CT and MR angiography interpretations (kappa values, 0.47-0.79; p < 0.001). Combining T2-weighted and T1-weighted MR cholangiography techniques detected all biliary anatomical variations in 9 of the 26 patients. MR-proton density fat fraction showed a sensitivity of 100% (3/3) and a specificity of 91.3% (21/23) for detecting pathologically determined steatosis (>5%). MR volumetry reached an excellent agreement with CT volumetry (reviewers 1 and 2: ICC, 0.92; 95% CI, 0.84-0.96).

CONCLUSION

Our one-stop comprehensive liver donor MR imaging protocol can provide complete information regarding hepatic vascular and biliary anatomies, hepatic parenchymal quality, and liver volume for living liver donor candidates and can replace composite multimodality evaluation.

Compressed sensing for breath-hold high-resolution hepatobiliary phase imaging: image noise, artifact, biliary anatomy evaluation, and focal lesion detection in comparison with parallel imaging

PURPOSE

To assess image quality, performance for biliary anatomy diagnosis, and focal lesion detection rate of breath-hold high-resolution 3D T1-weighted hepatobiliary phase imaging using compressed sensing (CS HBP) compared to standard HBP using conventional parallel imaging.

METHODS

This retrospective study assessed consecutive 125 patients who underwent CS HBP and standard HBP between November 2019 and July 2020. Optimized resolution and scan time for CS HBP were 1 × 1.4 × 1 mm³ and 15 s, while those for standard HBP were 1.3 × 1.8 × 3 mm³ and 16 s. Two independent radiologists evaluated qualitative indices on the clarity of liver margin, visibility of the hepatic vessel and bile duct, image noise, and artifact on a 5-point scale. Biliary anatomy, confidence for biliary anatomy diagnosis, expected number of bile duct openings, and number of focal lesions were assessed. Wilcoxon signed-rank test, Pearson chi-square test, and sensitivity for focal lesion were used for statistical analysis. Intraclass correlation coefficient (ICC) and Cohen's kappa (κ) were used to determine inter-observer agreement.

RESULTS

CS HBP showed significantly better liver edge sharpness and bile duct visualization, but greater subjective image noise and non-respiratory artifacts compared to standard HBP. CS HBP showed higher number of concordantly assigned biliary anatomy across readers (86 vs. 80), indicating greater inter-observer agreement for biliary anatomy (κ, 0.67 vs. 0.45) and the number of bile duct openings (ICC, 0.860 vs. 0.579) with significantly higher diagnostic confidence (4.70-4.74 vs. 3.96-4.55; p = 0.002). Both readers identified more focal lesions in CS HBP than in standard HBP (88.2% and 84.5% vs. 66.3% and 73.4%).

CONCLUSION

Breath-hold high-resolution CS HBP was a feasible clinical sequence providing superior liver edge sharpness, bile duct visualization, and focal lesion detection rate compared to standard HBP despite higher noise and artifact. Due to improved spatial resolution, CS HBP yielded a higher inter-observer agreement and confidence for the biliary anatomy diagnosis.

Virtual noncontrast images derived from dual-energy CT for assessment of hepatic steatosis in living liver donors

PURPOSE

This study aimed to investigate the correlation of attenuation between virtual noncontrast (VNC) and true noncontrast (TNC) CT images and compare the diagnostic performance for hepatic steatosis using MR spectroscopy (MRS) as the reference standard.

METHODS

A total of 131 consecutive hepatic donor candidates who underwent dual-source dual-energy CT and MRS within one month from January 2018 to April 2019 were included. An MRS value > 5.8 % was regarded as substantial hepatic steatosis. The correlation of attenuation between TNC and VNC in the liver and spleen, and liver attenuation index (LAI), defined as hepatic minus splenic attenuation, was evaluated using Spearman's rank correlation. The diagnostic performance of the LAI for hepatic steatosis was compared using receiver operating characteristic analyses.

RESULTS

Twenty-three candidates (17.6 %) had substantial hepatic steatosis. The median liver attenuation (66.7 [IQR, 63.5-70.9] vs. 63.5 [IQR, 60.3-66.9], p < .001) and LAI (12.9 [9.3-16.7] vs. 7.4 [3.9-11.9], p < .001) in the VNC were higher than those in the TNC. Hepatic attenuation (r = 0.93, p < .001), splenic attenuation (r = 0.55, p < .001), and LAI (r = 0.87, p < .001) were significantly correlated between TNC and VNC. Area under the curve of LAI in TNC and VNC were 0.88 (cutoff, LAI < 3.1) and 0.84 (cutoff, LAI < 10.1), respectively, indicating no statistically significant difference (p = 0.11).

CONCLUSION

The LAI of VNC is significantly correlated with that of TNC and might be feasible for diagnosing substantial hepatic steatosis in living liver donor candidates using different cutoff values of LAI.

Importance of Imaging Plane of Gadoxetic Acid--Enhanced Magnetic Resonance Cholangiography for Bile Duct Anatomy in Healthy Liver Donors

PURPOSE

The purpose of this study was to compare the image quality and accuracy of axial vs coronal contrast-enhanced magnetic resonance cholangiography (CE-MRC) for assessing bile duct anatomy.

METHODS

Data from 313 healthy donors who underwent axial and coronal CE-MRC before liver donation were retrospectively analyzed. Motion artifacts and bile duct visibility were assessed using 4-point scales, with scores ≥3 considered interpretable. The sensitivity and specificity of axial and coronal CE-MRC for diagnosing anatomic variations were compared, as were the proportions of correctly categorized biliary anatomic types.

RESULTS

Axial CE-MRC provided better image quality than coronal CE-MRC in terms of both motion artifacts (3.83 vs 3.17; P < .001) and duct visibility (3.50 vs 3.17, P < .001), resulting in more interpretable images with axial than coronal CE-MRC (92.7% vs 82.1%; P < .001). Among 249 donors with interpretable images, coronal CE-MRC performed significantly better for identifying duct anatomic variation than axial CE-MRC (sensitivity, 96.9% vs 80.4%, P < .001; specificity, 100% vs 96.7%, P = .025). Coronal CE-MRC was significantly better than axial CE-MRC at correctly categorizing anatomic types of right posterior hepatic duct into left hepatic duct and accessory duct with incomplete right hepatic duct.

CONCLUSIONS

With interpretable image quality, coronal CE-MRC performed better than axial CE-MRC for evaluating bile duct anatomy.

Assessment of biliary anatomy in potential living liver donors: Added value of gadoxetic acid-enhanced T1 MR Cholangiography (MRC) including utilization of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique in comparison to T2W-MRC

OBJECTIVES

To assess the added value of gadoxetic-acid-enhanced T1-weighted magnetic resonance Cholangiography (T1W-MRC) including controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)-Volumetric Interpolated Breathhold (VIBE) technique compared to T2-weighted MR Cholangiography (T2W-MRC) in depicting biliary anatomy in potential living liver donors.

METHODS

Eighty-five potential donors including 34 men with a mean age of 35.6 years (range, 18-55 years) and 51 women with a mean age of 36.7 years (range, 23-57 years), were enrolled in this ethics-approved retrospective study. Image quality for depiction of bile ducts was evaluated by two readers in consensus in 3 separate reading sessions: 1) T2W-MRC alone, 2) T1W-MRC alone (including CAIPI-VIBE and generalized autocalibrating partially parallel acquisitions (GRAPPA)-VIBE techniques, and 3) combined T1W/T2W-MRC. Accuracy of T2W-MRC, T1W-MRC, and combined T1W/T2W-MRC for the identification/classification of the biliary variants was calculated using intraoperative cholangiogram (IOC) as the reference standard. Image quality and reader diagnostic confidence provided by CAIPI-VIBE technique was compared with GRAPPA-VIBE technique. Datasets were compared using the Wilcoxon signed-rank test.

RESULTS

Image quality for depiction of the bile ducts was significantly superior in the combined T1W/T2W-MRC group, when compared to each of T2W-MRC and T1W-MRC groups independently (P value = 0.001-0.034). The combination of CAIPI-VIBE and GRAPPA-VIBE was superior compared to each of the sequences individually. The accuracy of T2W-MRC and T1W-MRC was 93% and 91%, respectively. T1W-MRC depicted four biliary variants better than T2W-MRC. Two variants not well seen in T2W-MRC were clearly shown on T1W-MRC.

CONCLUSION

Gadoxetic-acid-enhanced T1W-MRC and conventional T2W-MRC techniques are complementary for depiction of biliary variants in potential liver donors and the combination of the two improves the results. The combination of CAIPI-VIBE and GRAPPA-VIBE techniques appear to be complementary for optimal diagnostic yield of T1W-MRC.

The high-end range of biliary reconstruction in living donor liver transplant

PURPOSE OF REVIEW

To summarize recent evidence in literature regarding incidence and risk factors for biliary complications in living donor liver transplantation (LDLT), and current concepts in evaluation of donor biliary anatomy and surgical techniques of biliary reconstruction, to reduce the incidence of biliary complications.

RECENT FINDINGS

Advances in biliary imaging in the donor, both before surgery, and during donor hepatectomy, as well as safe hepatic duct isolation in the donor, have played a significant role in reducing biliary complications in both the donor and recipient. Duct-to-duct biliary anastomoses (DDA) is the preferred mode of biliary reconstruction currently, especially when there is a single bile duct orifice in the donor. The debate on stenting the anastomoses, especially a DDA, continues. Stenting a Roux en Y hepaticojejunostomy in children with small ductal orifices in the donor is preferred. With growing experience, and use of meticulous surgical technique and necessary modifications, the incidence of biliary complications in multiple donor bile ducts, and more than one biliary anastomoses can be reduced.

SUMMARY

Biliary anastomosis continues to be the Achilles heel of LDLT. Apart from surgical technique, which includes correct choice of type of reconstruction technique and appropriate use of stents across ductal anastomoses, better imaging of the biliary tree, and safe isolation of the graft hepatic duct, could help reduce biliary complications in the recipient, and make donor hepatectomy safe .