Fabian Morsbach, Presenter: Nothing to Disclose

Lotus May Desbiolles MD, Abstract Co-Author: Nothing to Disclose

Sebastian Leschka MD, Abstract Co-Author: Nothing to Disclose

Hatem Alkadhi MD, Abstract Co-Author: Nothing to Disclose

To investigate image quality and conspicuity of liver lesions on abdominal computed tomography (CT) images, reconstructed with advanced modeled iterative reconstruction (ADMIRE), sinogram-affirmed IR (SAFIRE) and filtered back projection (FBP).

Forty patients (19 female, mean age 63±14 years) with focal liver lesions (cysts, n=16; hemangiomas, n=6; metastases, n=18) undergoing standard portalvenous phase abdominal CT were included. Images were reconstructed with ADMIRE (strength levels 1-5), SAFIRE (strength levels 1-5), and FBP at a slice thicknesses of 2 mm. Two readers evaluated subjective image quality focusing on image appearance (score 1: no artifacts, 2: minor artifacts, blotchy, plastic-like appearance, 3: major artifacts, blotchy, plastic-like appearance, 4: artifacts making a diagnosis impossible), and visibility of small structures (score 1: excellent visibility, 2: above average, 3: average, 4: poor). Readers also rated the conspicuity of lesions (score 1: well-seen lesion, well delineated margin, score 2: well-seen lesion, poorly delineated margin, score 3: subtle lesions, score 4: probably an artifact mimicking a lesion). Attenuation (in HU) of the liver and subcutaneous fat and the standard deviation of attenuation indicating noise was measured. Friedman test and analysis of variance (ANOVA) were conducted.

Readers found a significantly improved image appearance for all strength levels of ADMIRE compared to the respective SAFIRE levels (P<0.001), as well as superior visibility of small structures (P<0.001). Lesion conspicuity was rated similarly with ADMIRE and SAFIRE (P>0.05) and superior to FBP at strength levels 3-5 (all,P<0.05). HU-values of the liver and fat did not vary with reconstruction algorithms (P>0.05). Noise decreased with increasing strength levels compared to FBP (P<0.05), with no differences among corresponding strength levels (P>0.05).

As compared to SAFIRE, ADMIRE improves image quality and reduces artificial image appearance at a similar noise reduction level without impairing lesion conspicuity.

Iterative reconstructions with a less artificial image appearance can be used for CT imaging at low radiation doses with a broader acceptance by radiologists in daily clinical routine.

Morsbach, F, Desbiolles, L, Leschka, S, Alkadhi, H, CT Imaging of the Liver: Comparison of Sinogram-affirmed with Advanced Modeled Iterative Reconstructions.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016656.html