Comparison of the extent and severity of myocardial perfusion defects measured by CT coronary angiography and SPECT myocardial perfusion imaging.
OBJECTIVE
We compared electrocardiogram-gated computed tomography (CT) myocardial perfusion imaging (MPI) based on quantification of the extent and severity of perfusion abnormalities to that measured with single-photon emission computed tomography (SPECT) MPI.


BACKGROUND
Contrast-enhanced CT-MPI has been used for the identification of myocardial ischemia.


METHODS
We performed CT-MPI during intravenous adenosine infusion in 30 patients with perfusion abnormalities on rest/adenosine stress SPECT-MPI acquired within 60 days (18 stress-rest CT-MPI and 12 stress CT-MPI only). The extent and severity of perfusion defects on SPECT-MPI were assessed on a 5-point scale in a standard 17-segment model, and total perfusion deficit (TPD) was quantified by automated software. The extent and severity of perfusion defects on CT-MPI was visually assessed by 2 observers using the same grading scale and expressed as summed stress score and summed rest score; visually quantified TPD was given by summed stress score/(maximal score of 68) and summed rest score/68. The magnitude of perfusion abnormality on CT-MPI in regions of the myocardium was defined.


RESULTS
On a per-segment basis, there was good agreement between CT-MPI and SPECT-MPI with a kappa of 0.71 (p < 0.0001) for detection of stress perfusion abnormalities. Automated TPD on SPECT-MPI was similar to visual TPD from CT-MPI (p = 0.65 stress TPD, and p = 0.12 ischemic TPD stress-rest) with excellent agreement (bias = -0.3 for stress TPD, and bias = 1.2 for ischemic TPD) on Bland-Altman analysis. Software-based quantification of the magnitude of stress perfusion deficit and ischemia on CT-MPI were similar to that for automated TPD measured by SPECT (p = 0.88 stress, and p = 0.48 ischemia), with minimal bias (bias = 0.6, and bias = 1.2).


CONCLUSIONS
Stress and reversible myocardial perfusion deficit measured by CT-MPI using a visual semiquantitative approach and a visually guided software-based approach show strong similarity with SPECT-MPI, suggesting that CT-MPI-based assessment of myocardial perfusion defects may be of clinical and prognostic value.
Department of Imaging, Division of Nuclear Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
Balaji K
BK
Tamarappoo
Damini
D
Dey
Ryo
R
Nakazato
Haim
H
Shmilovich
Thomas
T
Smith
Victor Y
VY
Cheng
Louise E J
LE
Thomson
Sean W
SW
Hayes
John D
JD
Friedman
Guido
G
Germano
Piotr J
PJ
Slomka
Daniel S
DS
Berman
D000241:Adenosine; D003287:Contrast Media; D017023:Coronary Angiography; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012984:Software; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014665:Vasodilator Agents
D003287:Contrast Media; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D000241:Adenosine