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

Feasibility of 3D Breath-Hold MR Cholangiopancreatography with a Spatially Selective Radiofrequency Excitation Pulse: Prospective Comparison with Parallel Imaging Technique and Compressed Sensing Method

RATIONALE AND OBJECTIVES

The purpose of the present study was to evaluate the clinical feasibility of the modified 3D breath-hold magnetic resonance cholangiopancreatography with parallel imaging (3D-BH-PI-MRCP) using a spatially selective radiofrequency excitation pulse in patients with suspected pancreaticobiliary diseases. Moreover, we also compared its image quality with those of the original 3D-BH-PI-MRCP with a nonselective exciting pulse and the 3D breath hold compressed sensing magnetic resonance cholangiopancreatography (3D-BH-CS-MRCP).

MATERIALS AND METHODS

Between January 2021 and July 2021, 106 patients prospectively underwent modified 3D-BH-PI-MRCP, original 3D-BH-PI-MRCP and 3D-BH-CS-MRCP at 3T in this study. The Friedman test was performed to compare the contrast, signal-to-noise-ratio (SNR), and contrast-noise-ratio, overall image quality, and duct visualization among the three protocols.

RESULTS

The contrast ratio, SNR and contrast-to-noise ratio of the common bile duct differed significantly among the three sequences (p < 0.001). Compared to the 3D-BH-CS-MRCP protocol, the overall imaging quality of the two 3D-BH-PI-MRCP was higher but not significantly different. The scores for the anterior and posterior branches visualization were significantly higher in the original 3D-BH-PI-MRCP compared to the 3D-BH-CS-MRCP, but were no significant differences between the modified 3D-BH-PI-MRCP and the 3D-BH-CS-MRCP.

CONCLUSION

The modified 3D-BH-PI-MRCP with a spatially selective radiofrequency excitation pulse could provide comparable image quality to the original 3D-BH-PI-MRCP and the 3D-BH-CS-MRCP during a single breath hold (22 seconds), and showed improved SNR and superior visualization of the pancreaticobiliary tree.

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.

Application of Compressed Sensing 3D MR cholangiopancreatography (CS-MRCP) with Contact-Free Physiological Monitoring (CFPM) for Pancreaticobiliary Disorders

RATIONAL AND OBJECTIVES

To prospectively evaluate the clinical feasibility of the magnetic resonance cholangiopancreatography (MRCP) protocol using both contact-free physiological monitoring (CFPM) and compressed sensing (CS) (CS-CFPM-MRCP) and to compare its performance with that of the standard navigator-triggered (NT) CS-NT-MRCP and NT-MRCP.

MATERIALS AND METHODS

A total of 63 patients (36 males, 27 females, age range: 18-83 years, mean age: 52.30 ± 15.70 years) suspected with duct-related pathologies were prospectively enrolled and performed the three MRCP protocols randomly. The acquisition time was compared. The pancreaticobiliary system was divided into 12 segments and evaluated based on a five-point Likert scale and compared by the Friedman test with a post hoc test. The diagnostic performance of the 3 MRCP was evaluated by the AUC value and compared by Delong's test. The interobserver agreement was evaluated by Kendall's W test.

RESULTS

Compared to NT-MRCP, the acquisition time of CS-NT-MRCP and CS-CFPM-MRCP was significantly decreased (both p < 0.001). There is no significant difference in the overall imaging quality (p > 0.05) between the NT-MRCP and CS-CFPM-MRCP protocols. CS-CFPM-MRCP depicted pancreatic duct and intrahepatic ducts better than CS-NT-MRCP (all p < 0.05) and was comparable with that of the NT-MRCP (all p > 0.05). For identification of abnormalities and diseases associated with MPD anatomy, the mean AUC value for NT-MRCP and CS-CFPM-MRCP were 0.896 (95%CI: 0.834, 0.958) and 0.905 (95%CI: 0.846, 0.964), which were significantly higher when compared to that for CS-NT-MRCP (0.713 [95%CI:0.622, 0.805]) (p = 0.001 and < 0.001). All evaluations showed good to excellent agreement (0.619-0.897).

CONCLUSION

The combination of CS and CFPM is considered feasible for shortening the scan time of 3D free breath MRCP without impairing the imaging quality and CS-CFPM-MRCP is considered feasible for patients suspected with pancreaticobiliary diseases.

Comparing compressed sensing breath-hold 3D MR cholangiopancreatography with two parallel imaging MRCP strategies in main pancreatic duct and common bile duct

PURPOSE

To evaluate the image quality and image consistency between 3D Breath-hold (BH)-MRCP with parallel imaging (3D-BH-PI-MRCP) and 3D-BH compressed sensing (CS)-MRCP (3D-BH-CS-MRCP) in patients with suspected pancreaticobiliary diseases, compared with 3D navigator-triggered (NT)-MRCP.

MATERIALS AND METHODS

The A total number of 109 patients who underwent 3D-NT-MRCP, 3D-BH-PI-MRCP and 3D-BH-CS-MRCP were prospectively enrolled in this study. The Friedman test was performed to compare quantitative values, image acquisition time, the presence of artifacts, overall image quality, and duct visualization among the three protocols. Additionally, we compared 3D-BH-PI-MRCP and 3D-BH-CS-MRCP with 3D-NT-MRCP in morphological consistency of main pancreatic duct and common bile duct (CBD) based on overall image quality score of = 4.

RESULTS

Three MRCP methods were successfully performed in all the patients. The contrast ratio, SNR and CNR of the CBD were significantly higher for 3D-BH-CS-MRCP than those for 3D-NT-MRCP and 3D-BH-PI-MRCP images. Overall image quality did differ significantly across the three sequences. Visualization of the CBD, RHD, LHD, anterior branch, posterior branch and cystic duct was similar with the 3D-BH-CS-MRCP and 3D-BH-PI-MRCP sequences. In contrast, segment 2 or 3 branch and main pancreatic duct visualization were significantly better with 3D-BH-PI-MRCP than with 3D-BH-CS-MRCP and 3D-NT-MRCP (p < 0.001).

CONCLUSIONS

Both the two breath-hold approaches were considering the time-saving advantages without deterioration of image quality. Compared with 3D-BH-CS-MRCP, 3D-BH-PI-MRCP yielded significantly better visualization of the segment 2 and 3 branch of the intrahepatic duct and performed better consistency in main pancreatic duct and common bile duct morphology.

Comparisons between image quality and diagnostic performance of 2D- and breath-hold 3D magnetic resonance cholangiopancreatography at 3T

OBJECTIVES

To compare the image quality and diagnostic performance of 2D MRCP to those of breath-hold 3D MRCP using compressed sensing (CS-MRCP) and gradient and spin-echo (GRASE-MRCP) at 3T.

METHODS

From January to November 2018, patients who underwent pancreatobiliary MRI including 2D MRCP and two breath-hold 3D MRCP using CS and GRASE at 3T were included. Three radiologists independently evaluated image quality, motion artifact, and pancreatic cyst conspicuity. Diagnostic performance was assessed for bile duct anatomic variation, bile duct, and pancreatic diseases using a composite algorithm as reference standards. Pancreatic lesion detectability and conspicuity were evaluated using JAFROC and generalized estimating equation analysis.

RESULTS

One hundred patients (male = 50) were included. Bile duct anatomic variation, bile duct and pancreatic diseases were present in respectively 31, 15, and 79 patients. Breath-hold 3D MRCP provided better image quality than 2D MRCP (3.5 ± 0.6 in 2D MRCP; 4.0 ± 0.7 in GRASE-MRCP and 3.9 ± 0.8 in CS-MRCP, p < 0.001 for both). There was no difference in motion artifact between 2D and breath-hold 3D MRCP (p = 0.1). Breath-hold 3D CS-MRCP provided better pancreatic cyst conspicuity than 2D MRCP (2.7 [95% CI: 2.5-3.0] vs. 2.3 [95% CI: 2.1-2.5], p = 0.001). There were no significant differences between the diagnostic performance of the three sequences in the detection of bile duct anatomic variation or pancreatic lesions (p > 0.05).

CONCLUSION

Breath-hold 3D MRCP with GRASE or CS can provide better image quality than 2D MRCP in a comparable scan time.

KEY POINTS

• Breath-hold 3D MRCP using compressed sensing (CS) or gradient and spin-echo (GRASE) provided a better image quality with less image blurring than 2D MRCP. • There were no significant differences between 2D MRCP and breath-hold 3D MRCP in either motion artifact or the number of non-diagnostic exams. • There were no significant differences between 2D MRCP and either type of breath-hold 3D MRCP in the diagnosis of bile duct anatomic variation or detection of pancreatic lesions.

Combination of compressed sensing and parallel imaging for T2-weighted imaging of the oral cavity in healthy volunteers: comparison with parallel imaging

OBJECTIVE

Compressed sensing (CS) and parallel imaging (PI) are magnetic resonance (MR) imaging acceleration techniques. Image quality of two-dimensional fast spin echo imaging of the oral cavity using CS or combined CS and PI has not been evaluated. The aim of this study was to compare the acquisition time and image quality between T2-weighted imaging (T2WI) with CS and PI (CSPI-T2WI) and T2WI with PI (PI-T2WI) of the oral cavity.

MATERIALS AND METHODS

Twenty healthy volunteers who underwent CSPI-T2WI and PI-T2WI of the oral cavity on a 3 T MR scanner were enrolled in the study. Contrast ratios of fat/muscle and bone/muscle on CSPI-T2WI and PI-T2WI were measured. Overall image quality, 4 kinds of artifacts, and visualization of 18 anatomical structures were independently evaluated by two radiologists with grading scales. The quantitative and qualitative measurements were compared between CSPI-T2WI and PI-T2WI by using the Wilcoxon signed-rank test.

RESULTS

Mean acquisition time of CSPI-T2WI and PI-T2WI was 72 s and 136 s, respectively (p < .001). CSPI-T2WI showed a significantly higher contrast ratio of fat/muscle than PI-T2WI (p < .01). There were no significant differences in the overall image quality, artifacts, and visualization of anatomical structures between CSPI-T2WI and PI-T2WI.

CONCLUSIONS

CSPI-T2WI of the oral cavity in healthy volunteers can provide a reduction in acquisition time without impaired image quality compared to PI-T2WI.

KEY POINTS

• The acquisition time of T2WI with the combined CS and PI provided a 47% reduction in acquisition time compared with T2WI with PI. • T2WI with the combined CS and PI did not show impaired image quality compared with T2WI with PI. • Combined CS and PI can be a useful technology to evaluate the oral cavity with high-speed acquisition.

High-resolution three-dimensional T1-weighted hepatobiliary MR cholangiography using Gd-EOB-DTPA for assessment of biliary tree anatomy: Parallel imaging versus compressed sensing

PURPOSE

To compare the quality of images obtained by T1-weighted hepatobiliary MR cholangiography using Gd-EOB-DTPA with 1-mm isovoxel acquisition and compressed sensing (T1-MRC_CS) or parallel imaging (T1-MRC_PI) for assessment of biliary tree anatomy.

METHOD

We prospectively reviewed T1-MRC_CS, T1-MRC_PI, and respiratory-triggered 3D T2-weighted MR cholangiography (T2-MRC) images in 58 patients. Two radiologists independently assessed the three sets of images and scored the biliary tree visualization and overall image quality in all cases using a 5-point Likert scale. The resulting scores were compared among T1-MRC_CS, T1-MRC_PI, and T2-MRC images using a Friedman test followed by a Scheffe test. The inter-reader agreement in scoring was assessed using κ statistics.

RESULTS

The image quality scores for the gallbladder on both T1-MRC_CS and T1-MRC_PI were significantly lower than those on T2-MRC (p < 0.01) for both readers. Meanwhile, the image quality scores for the right and left hepatic ducts and the anterior and posterior branches of the right hepatic duct on both T1-MRC_CS and T1-MRC_PI were significantly higher than those on T2-MRC (p < 0.05) for both readers. For Reader 2, the overall image quality scores on T1-MRC_CS and T1-MRC_PI were both significantly higher than those on T2-MRC (p < 0.05). There were no significant differences between the image quality scores on T1-MRC_CS and T1-MRC_PI for visualization of each bile duct (p < 0.05).

CONCLUSIONS

There may be no significant difference in quality between T1-MRC_CS images and T1-MRC_PI images for assessment of biliary tree anatomy, and both types of images may be better than T2-MRC images, although clinical indication is limited compared with T2-MRC.