Effect of image quality on diagnostic accuracy of noninvasive fractional flow reserve: results from the prospective multicenter international DISCOVER-FLOW study.
BACKGROUND
Fractional flow reserve calculated from coronary CT (FFR(CT)) is a novel method for determining lesion-specific ischemia.


OBJECTIVE
To assess the effect of CT quality on accuracy of FFR(CT), we compared performance of FFR(CT) with severe stenosis by CT in relation to image quality; heart rate; signal-to-noise ratio (SNR); and common CT artifacts, including calcification, motion, and poor contrast enhancement.


METHODS
FFR(CT) was performed on 159 vessels in 103 patients undergoing CT, FFR(CT), and FFR. Ischemia was defined as FFR(CT) and FFR ≤ 0.80, and severe stenosis by CT was defined by ≥50% reduction in luminal diameter. FFR(CT) and CT stenosis were compared with FFR, which served as the reference.


RESULTS
On a vessel basis, accuracy of FFR(CT) was higher than CT stenosis for satisfactory or poor quality CTs (87.5% vs 64.6%), for heart rates > 65 beats/min (100% vs 52.9%), and for SNR less than the median (26.3) (84.4% vs 64.1%). Accuracy of FFR(CT) was superior to CT stenosis in the presence of calcification (85.7% vs 66.7%), motion (90.5% vs 57.1%), and poor contrast opacification (100.0% vs 71.4%). Similar relations were observed for exploratory analyses of FFR(CT) and CT stenosis on a patient basis. In 42 subjects who underwent coronary calcium scanning, accuracy of FFR(CT) was 77.8% (n = 18), 100% (n = 11), and 100% (n = 13) for coronary calcium scores of 0-100, 101-400, and >400, respectively.


CONCLUSIONS
Accuracy of FFR(CT) is superior to CT stenosis for determining lesion-specific ischemia. The performance of FFR(CT) remains robust across an array of factors known to adversely affect CT quality.
Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA 90048, USA. james.min@cshs.org
James K
JK
Min
Bon-Kwon
BK
Koo
Andrejs
A
Erglis
Joon-Hyung
JH
Doh
David V
DV
Daniels
Sanda
S
Jegere
Hyo-Soo
HS
Kim
Allison
A
Dunning
Tony
T
Defrance
Jonathan
J
Leipsic
D017023:Coronary Angiography / Q000706:statistics & numerical data*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*