Sonja Kandel MD, Presenter: Nothing to Disclose

Henning Meyer MD, Abstract Co-Author: Nothing to Disclose

Patrik Rogalla MD, Abstract Co-Author: Nothing to Disclose

To compare two scanning protocols (free breathing versus breathhold) using dynamic volume CT scanning and to evaluate their effects on manual rigid image registration.

52 patients (mean age 61 years; 31 men; 21 women) underwent dynamic volume CT for perfusion analysis of focal pancreatic lesion and were randomly assigned to either free breathing (I) or multiple breathhold (II) group. CT scanning was performed using a 320-slice dynamic volume scanner after administration of contrast media. Patients were prepared with oxygen hyperventilation through a mask. Both dynamic CT protocols consisted of 15 intermittent low dose scans which were applied within 90 seconds. Group I was instructed to breathe as shallowly as possible during the entire examination. The longest breathhold sequence for group II lasted for 40 seconds. During post-processing, the scan with the highest contrast was determined as reference for manual rigid registration and every image was visually matched focused on the target lesion in the pancreas. The image mismatch per patient was calculated as the median of the 3D vector lengths of the registration offset. Statistic analysis was performed using the Wilcoxon rank sum test with continuity correction.

In all 52 patients, focused rigid image correction was feasible. 8% of the scans in group I and 14% in group II did not require manual image correction. The median registration shift for group I and II was 2.61 and 4.95 mm, respectively (p< 0.005).

Continous shallow breathing during dynamic volume CT scanning reduces the required amount of motion correction necessitating less overall user interaction.

Continous shallow breathing during perfusion imaging may improve implementation of perfusion analysis in clinical practice.  

Kandel, S, Meyer, H, Rogalla, P, Influence of Free Breathing on Motion Correction in Abdominal Perfusion Imaging Using Dynamic Volume CT.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9015526.html