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

Utility of the New Faster Compressed SENSE MRCP at 3 Tesla MRI in Children with Pancreatitis

OBJECTIVE

To compare the acquisition time, diagnostic efficacy, and image quality of the newer compressed SENSE 3D MRCP (CS-3D MRCP) with conventional 3D MRCP (C-3D MRCP) in children with pancreatitis.

METHODS

A total of 24 children (2-17 y) diagnosed with pancreatitis were included in this study. The children underwent CS-3D MRCP and C-3D MRCP sequences. C-3D MRCP and CS-3D MRCP images were evaluated for the acquisition time duration, visualization of the pancreaticobiliary ducts, background suppression, image quality degradation by artifacts, and overall image quality by the two radiologists independently. Paired sample t-test was used to compare the acquisition time, the McNemar test for the image quality features, and the kappa coefficient was used for interobserver agreement.

RESULTS

A two-fold decrease in the acquisition time of CS-3D MRCP (~148 ± 61 s) was seen, compared to C-3D MRCP (~310 ± 98 s), p < 0.001. The median scores for overall image quality on CS-3D MRCP and C-3D MRCP, respectively, were 2.05 ± 0.52 and 2.21 ± 0.53 (p = 0.18) for both radiologists. No significant difference was seen for the visibility of ducts, background suppression, and artifacts between the two radiologists, with substantial to almost perfect agreement seen for the different findings.

CONCLUSION

The application of compressed SENSE 3D MRCP in children with pancreatitis results in a two-fold reduction in acquisition time with acceptable image quality. This may help in reducing the need for long sedation in children requiring anesthesia support for the MRCP and potentially help in reducing motion artifacts.

Rapid 3D breath-hold MR cholangiopancreatography using deep learning-constrained compressed sensing reconstruction

OBJECTIVES

To compare the image quality of three-dimensional breath-hold magnetic resonance cholangiopancreatography with deep learning-based compressed sensing reconstruction (3D DL-CS-MRCP) to those of 3D breath-hold MRCP with compressed sensing (3D CS-MRCP), 3D breath-hold MRCP with gradient and spin-echo (3D GRASE-MRCP) and conventional 2D single-shot breath-hold MRCP (2D MRCP).

METHODS

In total, 102 consecutive patients who underwent MRCP at 3.0 T, including 2D MRCP, 3D GRASE-MRCP, 3D CS-MRCP, and 3D DL-CS-MRCP, were prospectively included. Two radiologists independently analyzed the overall image quality, background suppression, artifacts, and visualization of pancreaticobiliary ducts using a five-point scale. The signal-to-noise ratio (SNR) of the common bile duct (CBD), contrast-to-noise ratio (CNR) of the CBD and liver, and contrast ratio between the periductal tissue and CBD were measured. The Friedman test was performed to compare the four protocols.

RESULTS

3D DL-CS-MRCP resulted in improved SNR and CNR values compared with those in the other three protocols, and better contrast ratio compared with that in 3D CS-MRCP and 3D GRASE-MRCP (all, p < 0.05). Qualitative image analysis showed that 3D DL-CS-MRCP had better performance for second-level intrahepatic ducts and distal main pancreatic ducts compared with 3D CS-MRCP (all, p < 0.05). Compared with 2D MRCP, 3D DL-CS-MRCP demonstrated better performance for the second-order left intrahepatic duct but was inferior in assessing the main pancreatic duct (all, p < 0.05). Moreover, the image quality was significantly higher in 3D DL-CS-MRCP than in 3D GRASE-MRCP.

CONCLUSION

3D DL-CS-MRCP has superior performance compared with that of 3D CS-MRCP or 3D GRASE-MRCP. Deep learning reconstruction also provides a comparable image quality but with inferior main pancreatic duct compared with that revealed by 2D MRCP.

KEY POINTS

• 3D breath-hold MRCP with deep learning reconstruction (3D DL-CS-MRCP) demonstrated improved image quality compared with that of 3D MRCP with compressed sensing or GRASE. • Compared with 2D MRCP, 3D DL-CS-MRCP had superior performance in SNR and CNR, better visualization of the left second-level intrahepatic bile ducts, and comparable overall image quality, but an inferior main pancreatic duct.

Predicting the image quality of respiratory-gated and breath-hold 3D MRCP from the breathing curve: a prospective study

OBJECTIVES

To compare the image quality of breath-hold magnetic resonance cholangiopancreatography (BH-MRCP) and respiratory-gating MRCP (RG-MRCP), and to explore breathing curve-based factors and patient-related data affecting image quality.

METHODS

A total of 126 participants who underwent RG-MRCP and BH-MRCP on a 3-T magnetic resonance (MR) scanner were enrolled from May to December 2021. The images were evaluated by three radiologists on a 5-point scale. Respiratory parameters were extracted from the breathing curves. The Wilcoxon test was used to compare the image quality between the two MRCPs. Logistic regression analyzes were performed to identify age, sex, abdominal pain, and breathing predictor variables of better image quality.

RESULTS

BH-MRCP performed better in visualizing intrahepatic bile ducts and overall image quality than RG-MRCP (p < 0.01). Factors predicting relatively good image quality included lower standard deviation of the respiratory amplitude (SD_amp)-minimum-peak (odds ratio = 0.16, p < 0.01) for RG-MRCP and lower SD_amp (OR = 0.69, p < 0.01) for BH-MRCP.

CONCLUSIONS

BH-MRCP had significantly better overall image quality than RG-MRCP. Respiratory conditions exerted a significant impact on MRCP image quality, and parameters derived from the breathing curve could help predict the image quality of both sequences.

KEY POINTS

• Both breath-hold (BH) and respiratory-gating (RG) MRCP demonstrate satisfying image quality. • BH-GRASE-MRCP is significantly better than RG-MRCP at the group level, but not for every individual. • Respiratory conditions exert a significant impact on the image quality, and the breathing curve can help predict the image quality.

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.

Accelerated Pancreatobiliary MRI for Pancreatic Cancer Surveillance in Patients With Pancreatic Cystic Neoplasms

BACKGROUND

Pancreatobiliary MRI is often recommended for patients at risk of developing pancreas cancer. But the surveillance MRI protocol has not yet been widely accepted.

PURPOSE

To establish an accelerated MRI protocol targeting the table time of 15 minutes for pancreatic cancer surveillance and test its performance in lesion characterization.

STUDY TYPE

Prospective.

POPULATION

A total of 30 participants were enrolled, who were undergoing follow-up care for intraductal papillary mucinous neoplasms or newly diagnosed pancreatic cysts (≥10 mm) and were scheduled for or had recently undergone contrast-enhanced CT (CECT).

FIELD STRENGTH/SEQUENCE

A 3 T; heavily T2WI, 3D MRCP, DWI, dynamic T1WI, two-point Dixon.

ASSESSMENT

In-room time and table time were measured. Seven radiologists independently reviewed image quality of MRI and then the presence of high-risk stigmata and worrisome features in addition to diagnostic confidence for accelerated MRI, CECT, and the noncontrast part of accelerated MRI (NC-MRI).

STATISTICAL ANALYSIS

Fisher's exact test was used for categorical variables and either the Student's t-test or Mann-Whitney test was performed for continuous variables. The generalized estimated equation was used to compare the diagnostic performance of examinations on a per-patient basis. Interobserver agreement was evaluated via Fleiss kappa. A P value of <0.05 was considered to be statistically significant.

RESULTS

The in-room time was 18.5 ± 2.6 minutes (range: 13.7-24.9) and the table time was 13.9 ± 1.9 minutes (range: 10.7-17.5). There was no significant difference between the diagnostic performances of the three examinations (pooled sensitivity: 75% for accelerated MRI and CECT, 68% for NC-MRI, P = 0.95), with the highest significant diagnostic confidence for accelerated MRI (4.2 ± 0.1). With accelerated MRI, the interobserver agreement was fair to excellent for high-risk stigmata (κ = 0.34-0.98).

DATA CONCLUSION

Accelerated MRI protocol affords a table time of 15 minutes, making it potentially suitable for cancer surveillance in patients at risk of developing pancreatic cancer.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY STAGE: 2.