CT Detection of Myocardial Blood Volume Deficits: Dual-Energy CT Compared with Single-Energy CT Spectra
Purpose
Recently, dual-energy CT (DECT) has been described for the detection of myocardial blood volume deficits but to date the performance of DECT for this application has not systematically been compared with single-energy CT spectra.
Method and materials
With IRB approval 50 patients (32 men, mean age 61±12 years) 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 (depending on body habitus), 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), which has been 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 reconstruction strategies for myocardial blood volume deficits.
Results
Rest 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. However, we did not perform a direct comparison between single-energy and DECT acquisitions in the same patient, which would be desirable, but problematic at current, due to cumulative radiation exposure.
Clinical relevance/application
For the detection of myocardial perfusion deficits seen on SPECT, DECT-based analysis of myocardial iodine distribution is superior to single-energy CT spectra.
Submission Type: Scientific Presentations RSNA 2010
Authors: E M Arnoldi, MD, Charleston, SC; U J Schoepf, MD; Y Lee, MBBCh; P Costello, MD; M F Reiser, MD; B Ruzsics, MD, PhD; et al.
