Comparison of quantitative 3D magnetic resonance cholangiography measurements obtained using three different image acquisition methods

PURPOSE

To compare quantitative biliary measurements obtained with three different magnetic resonance cholangiopancreatography (MRCP) acquisition methods.

METHODS

This retrospective study was IRB-approved. Patients with combinations of clinically indicated 3D FSE MRCP with sensitivity encoding (SENSE), 3D FSE SENSE MRCP with compressed sensing (CS-FSE; acceleration factor 8), and 3D gradient and spin-echo (GRASE) MRCP, acquired between October 2018 and March 2020, were included. The MRCP + Tuning Threshold algorithm (Perspectum Ltd., Oxford, UK) was used to segment 3D biliary models from MRCP data, with multiple metrics quantified from the models. Single measure, two-way, mixed-effects intra-class correlations, Bland-Altman analyses, and Wilcoxon signed-rank tests were used to compare quantitative measurements.

RESULTS

From 160 MRCP datasets (25 3D FSE, 67 3D CS-FSE, 68 3D GRASE) in 69 patients, 48 datasets (7 [28%] 3D FSE, 14 [21%] 3D CS-FSE, 27 [40%] 3D GRASE) failed post-processing due to motion artifacts. The remaining 112 MRCP datasets (18 3D FSE, 53 3D CS-FSE, 41 3D GRASE) from 60 patients were included in the analysis. There was good to excellent agreement between 3D FSE and 3D CS-FSE MRCP for diameter of the left and right hepatic ducts, biliary volume, number and length of ducts, and total length of dilations (ICC: 0.83-0.93). The only metrics that exhibited good agreement between 3D FSE and 3D GRASE MRCP were biliary volume (ICC: 0.75) and total number of dilations (ICC: 0.77).

CONCLUSION

3D CS-FSE MRCP produces comparable biliary diameter metrics and global duct quantification to 3D FSE MRCP at a significantly reduced acquisition time.

Comparison of respiratory-triggered 3D MR cholangiopancreatography and breath-hold compressed-sensing 3D MR cholangiopancreatography at 1.5 T and 3 T and impact of individual factors on image quality

PURPOSE

To evaluate the image quality of an accelerated compressed-sensing single-breath-hold 3D magnetic resonance cholangiopancreatography (BH-CS-MRCP) prototype sequence compared to the standard 3D sequence with respiratory triggering (STD-MRCP) at 1.5 T and 3 T. To assess the individual factors that can affect image quality.

METHOD

This is a retrospective analysis. Both sequences (BH-CS-MRCP and STD-MRCP) were performed in 200 patients at 1.5 T and 200 patients at 3 T. Overall image quality and the visualization of the bilio-pancreatic ducts were rated on a 5-point scale. Image sharpness and background suppression were rated on a 4-point scale. A double reading was performed in 50 patients to assess the inter-observer reproducibility. Individual characteristics studied were gender, age, BMI, ascites, abdominal surface and breath-hold quality.

RESULTS

At 1.5 T, BH-CS-MRCP was inferior to STD-MRCP in terms of overall quality (p = 0.0046), background suppression (p < 0.0001), visualization of the cystic duct (p < 0.0001), the right bile duct (p = 0.0008), the left bile duct (p = 0.0152), and the main pancreatic duct (p < 0.0001). However, BH-CS-MRCP was sharper than STD-MRCP (p = 0.028). At 3 T, BH-CS-MRCP was superior to STD-MRCP for overall quality (p < 0.0001), sharpness (p < 0.0001), and visualization of the bilio-pancreatic ducts (p < 0.0001). Background signal was conversely better suppressed in STD-MRCP (p < 0.0001). At 1.5 T, the volume of ascites was inversely correlated with image quality for BH-CS-MRCP while BMI was inversely correlated with image quality for STD-MRCP. Breath-hold quality was correlated with image quality for BH-CS-MRCP at 1.5 T and 3 T.

CONCLUSION

BH-CS-MRCP is feasible in clinical routine at 1.5 and 3 T, yielding significantly better perceived image quality at 3 T but not at 1.5 T. BH-CS-MRCP appears to be influenced by ascites whereas STD-MRCP is influenced by BMI at 1.5 T. This study was approved by the Ethics Review Board for Research in Medical Imaging (IRB: CRM-2003-065).

Breath-hold compressed-sensing 3D MR cholangiopancreatography compared to free-breathing 3D MR cholangiopancreatography: prospective study of image quality and diagnostic performance in pancreatic disorders

PURPOSE

To compare image quality and diagnostic performance of three magnetic resonance cholangiopancreatography (MRCP) protocols in patients with suspected pancreatic abnormalities: free-breathing standard 3D-MRCP (STD), free-breathing compressed sensing 3D-MRCP (CS), and CS 3D-MRCP with acquisition during a single breath-hold > 20 s (BH-CS).

METHODS

Informed consent was obtained. We performed 57 MRCPs in 56 prospectively included patients (29 men, median age 59 years). The three protocols were performed in random order. Acquisition time was recorded. Two radiologists blinded to the protocols used 5-point scales to assess image quality parameters (overall image quality, amount of artifacts, background suppression, bile and pancreatic duct visualization) and diagnostic performance (anatomical variants, duct abnormalities, cystic lesions).

RESULTS

Acquisition time was 279 s with STD, 176 s with CS (-37%), and 22 s with BH-CS (-93%). STD and BH-CS were not significantly different for overall image quality, artifacts, or background suppression. The BH-CS group had fewer non-diagnostic scans (3% vs. 19% with STD and 21% with CS, p < 0.05), higher-quality scans (78% vs. 66% with STD and 58% with CS, p < 0.05), and milder artifacts (2% vs. 18% with STD and 16% with CS, p < 0.05). The main pancreatic duct was better visualized with BH-CS compared to STD (p = 0.015) and CS (p < 0.001). Diagnostic performance did not differ across the three protocols. There were fewer indeterminate scans in the BH-CS group.

CONCLUSION

3T BH-CS is reliable, saves time, and is not associated with decreases in image quality or diagnostic performance compared to STD and CS.