Hye-Jeong Lee MD, Presenter: Nothing to Disclose

Dong Jin Im, Abstract Co-Author: Nothing to Disclose

Yun Jung Kim MD, Abstract Co-Author: Nothing to Disclose

Jin Hur MD, Abstract Co-Author: Nothing to Disclose

Byoung Wook Choi MD, Abstract Co-Author: Nothing to Disclose

We evaluated the feasibility of dual-energy cardiac CT to determine extracellular volume (ECV) fraction in the assessment of cardiomyopathy with cardiac MRI as the reference standard.

Study participants provided written informed consent to participate in this institutional review board approved prospective study. ECV was measured in patients with cardiomyopathy according to the modified 16-segment model using the following equations; on cardiac MRI, ECV = (ΔR1 of myocardium/ΔR1 of blood) x (1-hematocrit), where ΔR1 was the change in T1 relaxivity between pre and post contrast; on cardiac CT, ECV = (ΔHU of myocardium/ΔHU of blood) x (1-hematocrit), where ΔHU was the overlay HU, which is the HU difference caused by iodine through material decomposition with the dual-energy technique. The paired student t-test and agreement using the intraclass correlation coefficient (ICC) for ECV measurement between cardiac CT and cardiac MRI were evaluated on per-segment and per-patient analysis.

Nineteen patients with 304 myocardial segments were evaluated. For per-segment analysis, cardiac CT demonstrated a mean overlay HU of blood that was 54.13 ± 7.57 HU and a mean overlay HU of the myocardium that was 33.46 ± 10.68 HU, with the resulting mean ECV being 35.98 ± 10.62%. The mean ECV on cardiac MRI was 35.51 ± 10.50%. There was no significant difference in mean values between cardiac CT and cardiac MRI (P = 0.105). For per-patient analysis, cardiac CT demonstrated a mean overlay HU of blood that was 54.13 ± 7.11 HU and a mean overlay HU of the myocardium that was 33.46 ± 8.54 HU, with the resulting mean ECV being 35.98 ± 8.30%. The mean ECV on cardiac MRI was 35.51 ± 8.61%. There was no significant difference in mean values between cardiac CT and cardiac MRI (P = 0.098). Also, excellent agreements were observed for ECV measurement between cardiac CT and cardiac MRI for both per-segment and per-patient analysis (ICC = 0.940 and 0.969, respectively).

ECV found with dual-energy cardiac CT showed excellent agreement with that found with cardiac MRI, suggesting the potential of myocardial tissue characterization with cardiac CT.

ECV measurement with dual-energy cardiac CT represents a new approach toward the clinical assessment of cardiomyopathy, particularly in patients with contraindications to cardiac MRI.

Lee, H, Im, D, Kim, Y, Hur, J, Choi, B, Myocardial Extracellular Volume Fraction with Dual-energy Cardiac Computed Tomography in Cardiomyopathy: Comparison with Cardiac Magnetic Resonance Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010310.html