Comparison of different magnetic resonance cholangiography techniques in living liver donors including Gd-EOB-DTPA enhanced T1-weighted sequences

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.

Correlation Among 3-Dimensional Magnetic Resonance Cholangiography, Intraoperative Cholangiography, and Intraoperative Findings in Right Liver Donors

OBJECTIVES

A correct preoperative definition of the hepatic duct confluence anatomy of right liver living donors is pivotal in determining their candidacy for donation and planning surgery during liver transplant. Here, we evaluated the accuracy of 3-dimensional magnetic resonance cholangiography compared with intraoperative cholangiography in assessing biliary anatomy and aimed to identify imaging characteristics that may help to predict the yield of hepatic duct orifices in the right liver graft.

MATERIALS AND METHODS

All consecutive living hepa-tectomy donors for adult liver transplant included in this study (N = 110) were evaluated with preoperative 3-dimensional magnetic resonance cholangiography, which was performed before and after intravenous administration of gadolinium (20-40 cm³). For intraoperative cholangiography, a 4F catheter was advanced through the cystic duct, and contrast matter (5-10 mL) was injected into the biliary tree via the catheter. The number of right hepatic ducts in explanted graft was determined on the back table.

RESULTS

Of 110 donors, 71 had type 1 (normal) biliary anatomy based on both 3-dimensional magnetic resonance and intraoperative cholangiography and 39 had abnormal biliary anatomy, with 2 having type 3 (abnormal) biliary anatomy. Normal biliary anatomy was found in back-table examination, and abnormal biliary anatomy (type 2) was found with intraoperative cholangiography. Sensitivity, specificity, and predic-tive values of 3-dimensional magnetic resonance cholangiography in revealing the biliary anatomy and anomalies were compared with intraoperative cholangiography findings. Observed final hepatic duct outcomes were also assessed. Use of 3-dimensional magnetic resonance cholangiography accurately predicted the biliary anatomy in 97 of 110 cases. Sensitivity was 80.4%, positive predictive value was 94.4%, specificity was 96.9%, and negative predictive value was 87.3%.

CONCLUSIONS

Three-dimensional magnetic resonance cholangiography reliably represented normal biliary anatomy; the presence of anatomic variations decreased its sensitivity, making intraoperative cholangiography or duct probing necessary tools to accurately perform right hepatic duct transection.

Balanced steady-state free precession MRCP is a robust alternative to respiration-navigated 3D turbo-spin-echo MRCP

Background

Despite synchronization to respiration, respiration-navigated (RN) 3D turbo-spin-echo MRCP is limited by susceptibility to motion artifacts. The aim of this study was to assess the quality of pancreaticobiliary duct visualization of a non-RN MRCP alternative based on balanced steady-state free precession imaging (BSSFP) with overlapping slices compared with RN-MRCP.

Methods

This is a retrospective study on 50 patients without pancreaticobiliary duct disease receiving MRCP at 1.5 T. We performed an intraindividual comparison of coronal RN-MRCP with combined coronal and transverse BSSFP-MRCP. Image quality was scored by 3 readers for 6 pancreaticobiliary duct segments (3 pancreatic, 3 biliary) using a 6-point scale. A segment score of 3 or lower as assessed by at least 2 of 3 readers was defined as insufficient segment visualization. Nonparametric tests and interrater reliability testing were used for statistical analysis.

Results

Overall duct visualization averaged over all readers was scored with 4.5 ± 1.1 for RN-MRCP (pancreatic, 4.1 ± 0.5; biliary, 5.0 ± 0.4) and 4.9 ± 0.9 for combined coronal and transverse BSSFP-MRCP (pancreatic, 4.6 ± 0.6; biliary, 5.1 ± 0.6), respectively (p < 0.001). The number of segments visualized insufficiently was 81/300 for RN-MRCP and 43/300 for BSSFP-MRCP (p < 0.001). Segments visualized insufficiently only in RN-MRCP had a mean score of 4.4 ± 0.8 in BSSFP-MRCP. Overall interrater agreement on superiority of BSSFP-MRCP segment scores over corresponding RN-MRCP was 0.70. Mean acquisition time was 98% longer for RN-MRCP (198.0 ± 98.7 s) than for combined coronal and transverse BSSFP-MRCP (100.2 ± 0.4 s).

Conclusions

Non-RN BSSFP-MRCP with overlapping slices is a fast alternative to RN-MRCP, frequently providing sufficient duct visualization when RN-MRCP fails.

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.

Preoperative magnetic resonance cholangiopancreatography before planned laparoscopic cholecystectomy: is it necessary?

Background:

The most feared complication of laparoscopic cholecystectomy (LC) is biliary tract injuries (BTI). We conducted a prospective study to evaluate the role of preoperative magnetic resonance cholangiopancreatography (MRCP) in describing the biliary tract anatomy and to investigate its potential benefit to prevent BTI.

Materials and Methods:

From January 2012 to December 2016, 402 patients who underwent LC with preoperative MRCP were prospectively included. Routine intraoperative cholangiography was not performed. Patients' characteristics, preoperative diagnosis, biliary anatomy, conversion to laparotomy, and the incidence of BTI were analyzed.

Results:

Preoperative MRCP was performed prospectively in 402 patients. LC was indicated for cholecystitis and pancreatitis, respectively, in 119 (29.6%) and 53 (13.2%) patients. One hundred and five (26%) patients had anatomical variations of biliary tract. Three BTI (0.75%) occurred with a major BTI (Strasberg E) and two bile leakage from the cystic stump (Strasberg A). For these 3 patients, biliary anatomy was modal on MRCP. No BTI occurred in patients presenting “dangerous” biliary anatomical variations.

Conclusion:

MRCP could be a valuable tool to study preoperatively the biliary anatomy and to recognize “dangerous” anatomical variations. Subsequent BTI might be avoided. Further randomized trials should be designed to assess its real value as a routine investigation before LC.

Is MRCP necessary to diagnose pancreas divisum?

Background

The purpose of this study is to compare the performance of three-dimensional magnetic resonance cholangiopancreatography (3D-MRCP) with non-MRCP T2-weighted magnetic resonance imaging (MRI) sequences for diagnosis of pancreas divisum (PD).

Methods

This is a retrospective study of 342 consecutive patients with abdominal MRI including 3D-MRCP. 3D-MRCP was a coronal respiration-navigated T2-weighted sequence with 1.5 mm slice thickness. Non-MRCP T2-weighted sequences were (1) a coronal inversion recovery sequence (TIRM) with 6 mm slice thickness and (2) a transverse single shot turbo spin echo sequence (HASTE) with 4 mm slice thickness. For 3D-MRCP, TIRM, and HASTE, presence of PD and assessment of evaluability were determined in a randomized manner. A consensus read by two radiologists using 3D-MRCP, non-MRCP T2-weighted sequences, and other available imaging sequences served as reference standard for diagnosis of PD. Statistical analysis included performance analysis of 3D-MRCP, TIRM, and HASTE and testing for noninferiority of non-MRCP T2-weighted sequences compared with 3D-MRCP.

Results

Thirty-three of 342 patients (9.7%) were diagnosed with PD using the reference standard. Sensitivity/specificity of 3D-MRCP for detecting PD were 81.2%/69.7% (p < 0.001). Sensitivity/specificity of TIRM and HASTE were 92.5%/93.9 and 98.1%/97.0%, respectively (p < 0.001 each). Grouped sensitivity/specificity of non-MRCP T2-weighted sequences were 99.8%/91.0%. Non-MRCP T2-weighted sequences were non-inferior to 3D-MRCP alone for diagnosis of PD. 20.2, 7.3%, and 2.3% of 3D-MRCP, TIRM, and HASTE, respectively, were not evaluable due to motion artifacts or insufficient duct depiction.

Conclusions

Non-MRCP T2-weighted MRI sequences offer high performance for diagnosis of PD and are noninferior to 3D-MRCP alone.

Trial registration

Not applicable.

Living Donor Liver Transplantation: Overview, Imaging Technique, and Diagnostic Considerations

OBJECTIVE. The purpose of this article is to discuss the process of becoming a liver donor, describe the surgical methods used for transplantation, and critically review preoperative and intraoperative imaging techniques. CONCLUSION. Radiologists play a vital role in ensuring the safety of living liver donors; however, consensus guidelines do not exist for imaging protocol or reporting. Standardization would provide more consistent image quality across centers, improve communication with the transplant team, and facilitate data mining for quality assurance and research.

Feasibility of gadoxetate disodium enhanced 3D T1 MR cholangiography (MRC) with a specific inversion recovery prepulse for the assessment of the hepatobiliary system

Aim

To compare the potential of a gadoxetate disodium enhanced navigator-triggered 3D T1 magnetic-resonance cholangiography (MRC) sequence with a specific inversion recovery prepulse to T2-weighted MRCP for assessment of the hepatobiliary system.

Materials and methods

30 patients (12 male, 18 female) prospectively underwent conventional navigator-triggered 3D turbo spin-echo T2-weighted MRCP and 3D T1 MRC with a specific inversion pulse to minimise signal from the liver 30 minutes after administration of gadoxetate disodium on a 1.5 T MRI system. For qualitative evaluation, biliary duct depiction was assessed segmentally following a 5-point Likert scale. Visualisation of hilar structures as well as image quality was recorded. Additionally, the extrahepatic bile ducts were assessed quantitatively by calculation of signal-to-noise ratios (SNR).

Results

The advantages of T1 3D MRC include reduced affection of image quality by bowel movement and robust depiction of the relative position of the extrahepatic bile ducts in relation to the portal vein and the duodenum compared to T2 MRCP. However, overall T1 3D MRC did not significantly (p > 0.05) improve the biliary duct depiction compared to T2 MRCP in all segments: Common bile duct 4.1 vs. 4.4, right hepatic duct 3.6 vs. 4.2, left hepatic duct 3.5 vs. 4.1. Image quality did not differ significantly (p > 0.05) between both sequences (3.6 vs. 3.5). SNR measurements for the hepatobiliary system did not differ significantly (p > 0.05) between navigator-triggered T1 3D MRC and T2 MRCP.

Conclusions

This preliminary study demonstrates that T1 3D MRC of a specific inversion recovery prepulse has potential to complement T2 MRCP, especially for the evaluation of liver structures close to the hilum in the diagnostic work-up of the biliary system in patients receiving gadoxetate disodium.

High spatial resolution navigated 3D T1-weighted hepatobiliary MR cholangiography using Gd-EOB-DTPA for evaluation of biliary anatomy in living liver donors

PURPOSE

To determine the feasibility of high-resolution navigated three-dimensional (3D) T1-weighted hepatobiliary MR cholangiography (Nav T1 MRC) using Gd-EOB-DTPA for biliary visualization in living liver donors and to assess added value of 3D T1-weighted hepatobiliary MRCs in improving the confidence and diagnostic accuracy of biliary anatomy in complementary to T2-weighted MRCs.

METHODS

Twenty-nine right liver donors underwent 3D T2 MRC, 2D T2 MRC, breath-hold T1-weighted hepatobiliary MRC (BH T1 MRC), and Nav T1 MRC. Two readers independently reviewed and compared 3D/2D MRC set, added BH T1 MRC set, and added Nav T1 MRC set for biliary diagnostic accuracy and confidence. For each MRC, biliary segments visualization and image quality were scored.

RESULTS

Both BH T1 MRC and Nav T1 MRC improved accuracy and specificity in biliary diagnosis when added to 3D/2D T2 MRC-alone set, though without statistical significance (R1, 82.8% to 93.1%; R2, 82.8% to 89.7%). The added Nav T1 MRC set showed the highest diagnostic confidence with both readers. Both readers scored Nav T1 MRC with the highest visualization scores for branching ducts and overall ducts.

CONCLUSION

Combining T1-weighted hepatobiliary MRCs to 3D/2D T2 MRC set improved accuracy for biliary anatomy diagnosis; time-efficient BH T1 MRC in axial and coronal planes should be considered as a key MRC sequence complementary to T2 MRCs. Given excellent biliary visualization and superior diagnostic confidence, Nav T1 MRC in selected subjects with breath-hold difficulties and inconclusive or complex biliary variations may assist in reaching a correct biliary diagnosis.

3D T2-weighted and Gd-EOB-DTPA-enhanced 3D T1-weighted MR cholangiography for evaluation of biliary anatomy in living liver donors

PURPOSE

To investigate whether the addition of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced 3D T1-weighted MR cholangiography (T1w-MRC) to 3D T2-weighted MRC (T2w-MRC) improves the confidence and diagnostic accuracy of biliary anatomy in living liver donors.

METHODS

Two abdominal radiologists retrospectively and independently reviewed pre-operative MR studies in 58 consecutive living liver donors. The second-order bile duct visualization on T1w- and T2w-MRC images was rated on a 4-point scale. The readers also independently recorded the biliary anatomy and their diagnostic confidence using (1) combined T1w- and T2w-MRC, and (2) T2w-MRC. In the 23 right lobe donors, the biliary anatomy at imaging and the imaging-predicted number of duct orifices at surgery were compared to intra-operative findings.

RESULTS

T1w-MRC had a higher proportion of excellent visualization than T2w-MRC, 66% vs. 45% for reader 1 and 60% vs. 31% for reader 2. The median confidence score for biliary anatomy diagnosis was significantly higher with combined T1w- and T2w-MRC than T2w-MRC alone for both readers (Reader 1: 3 vs. 2, p < 0.001; Reader 2: 3 vs. 1, p < 0.001). Compared to intra-operative findings, the accuracy of imaging-predicted number of duct orifices using combined T1w-and T2w-MRC was significantly higher than that using T2w-MRC alone (p = 0.034 for reader 1, p = 0.0082 for reader 2).

CONCLUSION

The addition of Gd-EOB-DTPA-enhanced 3D T1w-MRC to 3D T2w-MRC improves second-order bile duct visualization and increases the confidence in biliary anatomy diagnosis and the accuracy in the imaging-predicted number of duct orifices acquired during right lobe harvesting.

Comparison of gadoxetic acid to gadobenate dimeglumine for assessment of biliary anatomy of potential liver donors

PURPOSE

To compare MRI using gadobenate dimeglumine (Gd-BOPTA) vs. gadoxetic acid disodium (Gd-EOB-DTPA) for the assessment of biliary anatomy of potential liver donors.

METHODS

76 potential liver donors (39 M/37 F, mean 38 years) who underwent 1.5T MRI using Gd-BOPTA (n = 37) or Gd-EOB-DTPA (n = 39) were retrospectively evaluated. T2 cholangiogram (T2 MRC) and delayed hepatobiliary phase (HBP) T1 cholangiogram (T1 MRC) (performed during HBP 20 min after injection of Gd-EOB-DTPA and 1-2 h after Gd-BOPTA injection) were obtained in addition to MR angiogram/venogram. Two independent observers evaluated image quality (IQ) and conspicuity scores (CS) of the biliary system. Biliary anatomy was assessed in 3 reading sessions (T2 MRC, T1 MRC, and combined T2/T1 MRC). Reference standard consisted of consensus reading of two separate observers of all image sets, clinical/surgical information and intraoperative cholangiogram when available. Datasets were compared using the Mann-Whitney U test or Chi-squared test.

RESULTS

There was no difference in IQ for T1 MRC using either contrast agent or T2 MRC vs. T1 MRC for both observers (all p values >0.07). There was superior CS for T2 MRC vs. Gd-BOPTA T1 MRC for both observers and T2 MRC vs. Gd-EOB for one observer (p < 0.001). No difference was found for biliary variant detection for T1 MRC (with either contrast agent) vs. T2 MRC. Combined T2/T1 MRC demonstrated improved sensitivity for biliary variant detection using Gd-BOPTA for both observers (p < 0.004) and Gd-EOB-DTPA for one observer (p < 0.001).

CONCLUSION

Equivalent image quality was found for T1 MRC obtained with Gd-BOPTA or Gd-EOB-DTPA and T2 MRC. T1 MRC is equivalent to T2 MRC for detection of variant biliary anatomy, and the combination of sequences may have added value.