Michael Bristow MD, Presenter: Nothing to Disclose

Jia Wang PhD, Abstract Co-Author: Nothing to Disclose

Lior Molvin, Abstract Co-Author: Advisory Board, Bracco Group Speakers Bureau, General Electric Company

Nancy Ware RT, Abstract Co-Author: Nothing to Disclose

Dung Nguyen MD, Abstract Co-Author: Nothing to Disclose

Dominik Fleischmann MD, Abstract Co-Author: Research support, Siemens AG

Assessment of deep inferior epigastric artery (DIEA) perforating branches for free tissue transfer is challenging given their small size and low contrast (or attenuation) difference relative to abdominal wall musculature. The purpose of this study was to determine if high matrix size (1024 x 1024) model based iterative reconstruction (MBIR1024) improves spatial resolution and image noise characteristics compared to 512 x 512 filtered back projection reconstruction (FBP512) and if this can translate into improved visualization of DIEA branches.

Spatial resolution was assessed with a line-pair phantom and by calculating the modulation transfer function (MTF) from a wire phantom. Sixteen subjects who underwent high resolution CTA of the abdomen and pelvis were retrospectively identified. Axial images were reconstructed using FBP512 and MBIR2014. Regions of interest (ROI) were drawn in rectus muscles, external iliac arteries (EIA) and DIEAs. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated using noise within rectus muscles as a reference. Two independent readers rated the visualization of 3 DIEA branches (4-point scale) on each side in all 16 subjects using axial thick-slab MIP images reconstructed from FBP512 and MBIR1024 studies in random order. Statistical comparisons were performed using paired t-tests.

Phantom studies reveal improved spatial resolution of MBIR1024 over FBP512 (10 vs 7 line-pairs/cm, f50 of MTF equals 0.61 mm-1 vs 0.41 mm-1). MBIR1024 results in higher SNR and CNR compared to FBP512 for all ROIs tested (p < 0.001). Of specific interest, mean CNR for DIEAs vs rectus muscles was 28.7 for MBIR1024 in comparison to 15.9 for FBP512. On visualization analysis, DIEA branches scored on average higher on MBIR1024 than on FBP512 (14.06/24 for MBIR1024 and 12.25/24 for FBP512, p < 0.001).

MBIR1024 provides improved spatial resolution while simultaneously reducing image noise in comparison to FBP512. These superior image quality characteristics improve contrast between DIEAs and rectus muscles and results in better visualization of DIEA perforators for pre-surgical assessment prior to free tissue transfer.

Superior spatial resolution and image quality of high matrix size MBIR improves visualization of deep inferior epigastric arteries, which may aid in pre-surgical planning for free tissue transfer.

Bristow, M, Wang, J, Molvin, L, Ware, N, Nguyen, D, Fleischmann, D, Improved Visualization of Deep Inferior Epigastric Arteries on CTA with High Resolution Model Based Iterative Reconstruction.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019229.html