Application of compressed sensing to 3D magnetic resonance cholangiopancreatography for the evaluation of pancreatic cystic lesions.

The aim of this study was to assess changes in acquisition time, image quality and evaluation of pancreatic cysts when applying CS to a 3D MRCP sequence. Thirty subjects (17F; 13M) undergoing MRCP for evaluation of pancreatic cyst(s) were prospectively recruited and underwent 3D MRCP and CS 3D MRCP (CS factor = 2) on a 3T scanner. The acquisition time was recorded. Two experienced radiologists independently recorded quality of the images, presence of artifacts, visualization of the main pancreatic duct, bile ducts and index pancreatic cyst using a five-point scale. Presence of mural nodules and septations in the cyst, size of the cyst and caliber of the main pancreatic duct were also recorded. A paired sample t-test was used to compare the acquisition time of 3D MRCP and CS 3D MRCP. Image quality metrics and visualization of cyst features were compared with Wilcoxon signed-rank test and McNemar test. The mean acquisition time of CS-3D-MRCP (150 ±â€¯63 s) was significantly lower than that of 3D-MRCP (317 ±â€¯104 s; P < 0.001). The median score of overall quality (reader 1, 3.7 ±â€¯1.0 vs. 3.4 ±â€¯1.1, P = 0.11; reader 2, 3.8 ±â€¯1.0 vs. 3.7 ±â€¯1.1, P = 0.36), artifacts and visualization of the bile ducts were not significantly different between 3D-MRCP and CS-3D-MRCP. There was no significant difference in the visualization score of the index pancreatic cyst (reader 1, 4.2 ±â€¯0.9 vs. 4.1 ±â€¯0.9, P = 0.42; reader 2, 4.2 ±â€¯0.4 vs. 4.0 ±â€¯0.7, P = 0.27) and no difference in the assessment of cyst features. Applying CS to 3D-MRCP yields a two-fold reduction in acquisition time with comparable image quality and visualization of key pancreatic cyst features.

Direct comparison of computed tomography and magnetic resonance imaging for characterization of posterior left atrial morphology.

OBJECTIVE: Accumulating evidence points to the central importance of the posterior left atrium (PLA) for atrial fibrillation (AF). Catheter ablation intended to cure AF is increasingly practiced; performance and assessment of this procedure is enhanced by accurate imaging of PLA anatomy. Prior reports have suggested that both computed tomographic (CT) and magnetic resonance (MR) imaging techniques provide accurate PLA images. These techniques have never been compared directly. MATERIALS AND METHODS: Twenty patients referred for catheter ablation underwent preoperative imaging using both CT and MR. Each technique was used to create a multidimensional image of the PLA. RESULTS: Within patients, morphologic and dimensional PLA indices, including number of individual pulmonary venoatrial junctions, presence of ostial branches, circumference of each venoatrial junction, venoatrial junction "non-circularity", and distance between ipsilateral superior and inferior venoatrial junctions, were well correlated. CONCLUSIONS: CT and MR-based images of the PLA appear comparable. Technique selection should involve considerations of toxicity, tolerance, and local resources.