Date of Award


Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Daniel Cornfeld

Second Advisor

Hamid Mojibian


THE EFFECT OF LEFT- VERSUS RIGHT-SIDED CONTRAST INFUSION ON ATTENUATION IN CHEST CT ANGIOGRAMS Lars J. Grimm, Daniel Cornfeld, Hamid R. Mojibian. Department of Diagnostic Radiology, Yale University, School of Medicine, New Haven, CT. This study assesses if the arm of contrast infusion influences attenuation of the main pulmonary artery in CT angiograms to evaluate for pulmonary emboli. With IRB approval, 407 consecutive CT angiograms performed to exclude pulmonary emboli were reviewed. Patient characteristics, study details, and interpretation results were collected. After exclusion criteria were applied, 100 studies from each of our three scanners (4, 16, and 64 slice) remained. A reader, blinded to injection side, reviewed the images and recorded the attenuation of the main pulmonary artery. The average post-contrast attenuation in the main pulmonary artery was similar if infused through the right (275.4 HU) or left (275.0 HU) arm when controlling for confounders with a multiple regression analysis (p = 0.82). There was no statistical difference (p > 0.05) in the number of scans with attenuation less than 250 (45.9% right, 42.9% left), 200 (25.0% right, 29.0% left), or 150 HU (11.6% right, 12.3% left) and no difference in the number of scans interpreted as indeterminate (1% right, 4% left) or non-diagnostic (3% right, 3% left). Main pulmonary artery attenuation is not dependent on the arm of infusion when evaluating mean attenuation, attenuation beneath thresholds of 250, 200, or 150 HU, or indeterminate or non-diagnostic interpretations for patients undergoing a CT angiogram of the chest to rule out pulmonary emboli.