Automated quantitation of pericardiac fat from noncontrast CT.
BACKGROUND
Increased abdominal visceral fat has been shown to be a cardiovascular risk factor. Preliminary studies indicate that pericardiac fat (PF) may provide similar information. We aimed to develop new software (QFAT) for automatic quantitation of PF from noncontrast cardiac CT and compare PF measures to other cardiovascular risk factors.


METHODS
QFAT accepts user-defined range of noncontrast transverse cardiac CT slices, automatically segments the heart, and determines PF volume (PFV) as contiguous pericardial fat voxels. PFV normalized to cardiac volume defines PF ratio (PFR). QFAT and manual processing (MAN) was performed in 105 patients (mean BMI, 27; range, 17-41) by 2 observers.


RESULTS
Mean processing time was 20 +/- 4 seconds for QFAT, and 9 +/- 6 minutes for MAN. There was excellent agreement between QFAT and MAN for PFV (R = 0.98) and PFR (R = 0.98). MAN and QFAT interobserver variability were comparable. Interscan and interscanner variability for PFV and PFR were comparable to corresponding interobserver variability. PFV (R = 0.88, P < 0.0001) and PFR (R = 0.81, P < 0.0001) correlated strongly with abdominal visceral fat area, moderately with BMI (R = 0.58, P < 0.0001 and R = 0.48, P < 0.0001), and weakly with abdominal subcutaneous fat area (R = 0.33, P < 0.0001 and R = 0.32, P = 0.001).


CONCLUSIONS
PFV and PFR can be accurately and automatically quantified from noncontrast CT acquired for coronary calcium screening and may provide complementary information regarding cardiovascular risk.
Dey
Damini
D
Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Suzuki
Yasuyuki
Y
Suzuki
Shoji
S
Ohba
Muneo
M
Slomka
Piotr J
PJ
Polk
Donna
D
Shaw
Leslee J
LJ
Berman
Daniel S
DS
D050153:Abdominal Fat / Q000473:pathology*; D050154:Adiposity; D000368:Aged; D000465:Algorithms; D002114:Calcinosis / Q000175:diagnosis* / Q000473:pathology; D003327:Coronary Disease / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000473:pathology* / Q000502:physiology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000295:instrumentation*