First-arterial-pass dual-energy CT for assessment of myocardial blood supply: do we need rest, stress, and delayed acquisition? Comparison with SPECT.
OBJECTIVE
To compare the relative contributions of rest, stress, and delayed acquisitions with the accuracy of dual-energy (DE) computed tomography (CT) for the assessment of myocardial blood supply.


METHODS
With institutional review board approval and HIPAA compliance, 55 consecutive patients (10 women, 45 men; mean age, 62 years ± 10) clinically referred for cardiac single photon emission computed tomography (SPECT) who were known to have or were suspected of having coronary artery disease were prospectively enrolled. DE CT studies were acquired during adenosine stress, at rest, and after 6-minute delay. The DE CT iodine distribution maps were visually assessed for perfusion deficits or late iodine enhancement. Per-segment agreement between modalities was investigated with κ statistics. Test characteristics for the detection of perfusion deficits were calculated for combinations of rest, stress, and delayed DE CT acquisition, with SPECT as reference standard.


RESULTS
At SPECT, 714 segments were considered normal, 192 showed fixed perfusion defects, and 29 showed reversible perfusion deficits. Sensitivity of rest-only DE CT was 92%, and specificity was 98%. Stress-only, rest-stress, stress and delayed, and the combination of all three had a sensitivity of 99% and a specificity of 97%. Of 29 segments with reversible perfusion deficits at SPECT, 13 (45%) were misclassified by using rest-stress DE CT as fixed perfusion deficits. With stress DE CT plus delayed acquisition, 13 of 192 (7%) segments with fixed perfusion deficits at SPECT were misclassified as reversible.


CONCLUSIONS
Rest-stress acquisition should be the protocol of choice for assessment of the myocardial blood supply in DE CT. The accuracy of DE CT is not increased by the addition of a delayed DE CT acquisition, which may therefore be omitted to reduce radiation exposure. With rest-stress DE CT, almost one-half of defects that are reversible at SPECT were classified as fixed; radiologists and clinicians need to be aware of this incongruence when they interpret DE CT myocardial perfusion studies.
From the Department of Radiology and Radiological Science (F.G.M., C.N.D.C., U.J.S., J.W.N., J.R.S., T.H.) and Division of Cardiology, Department of Medicine (U.J.S., B.A.F.), Medical University of South Carolina, Ashley River Tower, MSC 226, 25 Courtenay Dr, Charleston, SC 29425; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (F.G.M.); Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.); the Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, Md (J.W.N.); and Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany (T.H.).
Felix G
FG
Meinel
Carlo N
CN
De Cecco
U Joseph
UJ
Schoepf
John W
JW
Nance
Justin R
JR
Silverman
Brian A
BA
Flowers
Thomas
T
Henzler
D000241:Adenosine; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide; D000241:Adenosine