Small Field-of-View T2-Weighted MRI of the pancreas in a Screening Setting for Hereditary Pancreatic Cancer: Improving Image Quality Through Radial K-Space Sampling

Author(s): Bas Boekestijn, Aleksander Bogdanski, Shirin Feshtali, Andrew G Webb, Rob J van der Geest, Martin N Wasser

Background: Radial k-space sampling is compared with conventional cartesian k-space sampling in small field-of -view respiratory-triggered Turbo Spin Echo (TSE) T2-weighted imaging of the pancreas regarding image quality and artifacts in a screening program for hereditary pancreatic cancer. Methods: Small field-of-view radial and cartesian k-space sampled respiratory triggered TSE images were acquired in 40 healthy mutation carriers undergoing annual screening for pancreatic cancer. Two radiologists evaluated images for motion artifacts, anatomical sharpness, pancreatic duct conspicuity and sharpness of vessels using a five-point Likert scale (1=very poor, 5=excellent) and reported their preferred sequence. Contiguousness between slices was quantified by segmentation of the superior mesenteric vein and determining the continuity of the vessel wall on consecutive slices by determining the deviation of the superior mesenteric vein center points. Results: All categories except in-plane motion artifacts yielded statistically significant differences (p<0.001). Radial sampling performed better in slice contiguousness, anatomical sharpness and sharpness of vessel walls. Pancreatic duct conspicuity was higher on the cartesian approach. Slice contiguousness had an average score of 4.53 ± 0.71 for radial and 3.46 ± 0.76 for cartesian TSE. Radial sampling was preferred in 65 cases (81.3%). The average deviation of the superior mesenteric vein center points was 1.45 mm (interquartile range (IQR) 1.08 – 2.06) on radial TSE and 2.31 mm (IQR 1.65 – 3.30) on cartesian TSE, p < 0.001. Conclusion: Radial k-space sampling yields better overall image quality and contiguousness between slices compared to cartesian sampling in high-resolution respiratory triggered T2-TSE of the pancreas.