Seth Jay Kligerman MD, Presenter: Author, Reed Elsevier

Kian Lahiji MD, Abstract Co-Author: Nothing to Disclose

Cheng Ting Lin MD, Abstract Co-Author: Nothing to Disclose

Jean Jeudy MD, Abstract Co-Author: Nothing to Disclose

Robert Daniel Pugatch MD, Abstract Co-Author: Nothing to Disclose

Elizabeth Kristine Weihe MD, Abstract Co-Author: Author, Amirsys, Inc

Aletta Ann Frazier MD, Abstract Co-Author: Nothing to Disclose

Charles S. White MD, Abstract Co-Author: Nothing to Disclose

Jeffrey R. Galvin MD, Abstract Co-Author: Nothing to Disclose

To determine if a model-based iterative reconstruction (MBIR) improves diagnostic confidence and detection of pulmonary embolism (PE) compared to hybrid iterative reconstruction (HIR) and filtered back projection (FBP) reconstructions in patients undergoing CT pulmonary angiography (CTPA).

The study had IRB approval and was HIPPA compliant. 50 patients underwent CTPA at 100kV using  departmental protocol. 22/50 patients had studies positive for PE as determined by two radiologists not involved in the reader study. The 50 studies were reconstructed with FBP, HIR (iDoseL3, Philips), and MBIR (IMR, Philips). Noise, attenuation, and contrast-to-noise (CNR) were recorded. After image randomization, five thoracic radiologists and two thoracic radiology fellows graded each study on a scale of 1 (very poor) to 5 (ideal) in four categories: diagnostic confidence, noise, PA enhancement and plastic appearance. Readers also marked each study for the presence or absence of PE. Parametric and non-parametric data were analyzed with a repeated measures ANOVA and Friedman’s ANOVA, respectively. After Bonferroni correction, significance of pairwise comparisons was set at p<0.0167.

CNR of MBIR (19.7) was signficantly higher than CNR of FBP (7.1) and HIR (10.3, p<0.0001 for both). Pooled sensitivity for detection of PE was 76% (117/154), 78.6% (121.154) and 82.5% (127/154) using FBP, HIR, and MBIR, respectively. With MBIR, detection of PE significantly increased compared to FBP (p=0.016). Detection of PE was not significantly higher with MBIR than HIR (p=0.045). Due to the non-significant increase in FP studies using HIR and MBIR (p=0.153), accuracy with MBIR (88.6%), HIR (87.1%), and FBP (87.7%) was similar. Compared to FBP, MBIR led to a significant subjective increase in diagnostic confidence, noise, and enhancement in 6/7, 6/7, and 7/7 readers, respectively. Compared to HIR, MBIR led to significant subjective increase in diagnostic confidence, noise, and enhancement in 5/7, 5/7, and 5/7 readers, respectively. All seven readers graded MBIR as having a significantly increased plastic appearance compared to both FBP and HIR.

MBIR led to a significant increase in PE detection compared to FBP. MBIR led to qualitative improvements in diagnostic confidence compared to both FBP and HIR.

In CTPA, MBIR can be safely integrated into clinical practice and can increase detection of PE

Kligerman, S, Lahiji, K, Lin, C, Jeudy, J, Pugatch, R, Weihe, E, Frazier, A, White, C, Galvin, J, Detection of Pulmonary Embolism on CT: Improvement Using a Model-based Iterative Reconstruction Algorithm Compared to a Filtered Back Projection Algorithm.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006207.html