Diffusion-weighted imaging of the abdomen at 3 T: image quality comparison with 1.5-T magnet using 3 different imaging sequences.

OBJECTIVE: This study aimed to perform comparisons between diffusion-weighted imaging (DWI) sequences at 3 T with 1.5 T. METHODS: Thirteen healthy volunteers underwent abdominal DWI on both 3- and 1.5-T magnets using 3 sequences including breath hold without parallel imaging (PI), breath hold with PI, and free breathing with PI at b50 and b1000. Artifacts and subjective image quality scores, signal intensity, and apparent diffusion coefficient were compared. RESULTS: For breath hold without PI, higher artifact was noted at 3 T b50 compared with 1.5 T (P < 0.0001). For b50 and b1000 breath hold with PI, artifacts were not different between the magnets, but image quality was better at 3 T (P = 0.04 and P = 0.02, respectively). For b50 and b1000 free breathing sequences, artifact and image quality scores were significantly better at 1.5 T. For breath hold acquisitions, the signal-to-noise ratio of gallbladder, kidneys, and pancreas was generally higher and that of the liver was lower on 3 T. Imaging at 3 T showed significantly higher image quality and lower artifacts for breath hold with PI compared with free breathing. Most apparent diffusion coefficients were not significantly different between the 2 magnets (P > 0.05). CONCLUSIONS: Three-tesla magnets can provide good images using breath hold with PI sequence.

Cardiac conduction system: delineation of anatomic landmarks with multidetector CT.

Major components of the cardiac conduction system including the sinoatrial node (SAN), atrioventricular node (AVN), the His Bundle, and the right and left bundle branches are too small to be directly visualized by multidetector CT (MDCT) given the limited spatial resolution of current scanners. However, the related anatomic landmarks and variants of this system a well as the areas with special interest to electrophysiologists can be reliably demonstrated by MDCT. Some of these structures and landmarks include the right SAN artery, right atrial cavotricuspid isthmus, Koch triangle, AVN artery, interatrial muscle bundles, and pulmonary veins. In addition, MDCT has an imperative role in demarcating potential arrhythmogenic structures. The aim of this review will be to assess the extent at which MDCT can outline the described anatomic landmarks and therefore provide crucial information used in clinical practice.