Rofo 2010; 182 - V4
DOI: 10.1055/s-0029-1247971

CT Detection of Myocardial Blood Volume Deficits: Dual-Energy CT Compared with Single-Energy CT Spectra – Performance of Dual-Energy CT and Single-Energy CT in Detection of Myocardial Ischemia

EM Arnoldi 1, B Ruzsics 2, YS Lee 2, M Gebregziabher 3, MF Reiser 1, P Costello 2, UJ Schoepf 2
  • 1Institut für Klinische Radiologie, Ludwig-Maximilians-Universität München, München
  • 2Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston SC, South Carolina, USA
  • 3Department of Biostatistics & Epidemiology, Medical University of South Carolina, Charleston SC, South Carolina, USA

Purpose: Recently, dual-energy CT (DECT) has been described for the detection of myocardial blood volume deficits but the performance of DECT for this application has not systematically been compared with single-energy CT spectra. Methods: 50 patients (32 men, age 61±12y) underwent SPECT myocardial perfusion imaging and DECT on a dual-source CT scanner. The A- and B-tubes were operated with 140kV and 80kV or 100kV, respectively. DECT raw data was reconstructed by: 1) only using high (140kV) energy CT spectra; 2) only using low (80kV/100kV) energy CT spectra, which have been described as superior for detection of myocardial blood volume deficits; 3) merging data (30% low and 70% high energy CT spectra), described as most comparable to routine 120kV scanning; 4) DECT-based overlay of iodine distribution on "virtual non-contrast" reconstructions. Two independent, blinded observers analyzed all data based on each of the four reconstructions for myocardial blood volume deficits. Results: SPECT MPI showed 203/850 myocardial segments with fixed perfusion defects. For the CT detection of segments with perfusion defects seen on SPECT, analysis using Receiver Operating Characteristics revealed an Area Under the Curve (AUC) for observer 1 and 2, respectively, of 0.66/0.67 based on high (140kV) energy CT spectra, 0.75/0.75 with low (80kV/100kV) energy CT spectra, 0.79/0.82 with merged (30%/70%) CT spectra, and 0.86/0.93 with DECT-based iodine analysis (p=0.036). Interobserver correlation was very good to excellent (κ=0.86–0.92). Conclusion: Although single-energy CT spectra can detect myocardial blood volume deficits as previously described, diagnosis is more accurate based on DECT.

While single image reconstructions (1) based on 140kV do not reveal perfusion deficits, single image reconstructions based on 100kV (2) and merged image reconstructions (3) show areas of hypoattenuation in the infarcted myocardium. DECT blood pool map clearly visualizes persistent lateral ischemia (4) in good corrleation with fixed perfusion defect on SPECT (5).

Fig. 1 Contrast-enhanced retrospectively ECG-gated DECT study in a 60-year-old man with known CAD and history of prior LCx infarct

cardiac CT - myocardial perfusion imaging