Influence of increasing convolution kernel filtering on plaque imaging with multislice CT using an ex-vivo model of coronary angiography.
OBJECTIVE
To assess the variability in attenuation of coronary plaques with multislice CT-angiography (MSCT-CA) in an ex-vivo model with varying convolution kernels.


METHODS
MSCT-CA (Sensation 16, Siemens) was performed in three ex-vivo left coronary arteries after instillation of contrast material solution (Iomeprol 400 mgI/ml, dilution: 1/80). The specimens were placed in oil to simulate epicardial fat. Scan parameters: slices 16/0.75 mm, rotation time 375 ms, feed/rotation 3.0 mm, mAs 500, slice thickness 1 mm, and FOV 50 mm. Datasets were reconstructed using 4 different kernels (B30f-smooth, B36f-medium smooth, B46f-medium, and B60f-sharp). Each scan was scored for the presence of plaques. Once a plaque was detected, the operator performed attenuation measurements (HU) in coronary lumen, oil, calcified and soft plaque tissue using the same settings in all datasets. The results were compared with T-test and correlated with Pearson's test.


RESULTS
Overall, 464 measurements were performed. Significant differences (p<0.05) were found for the mean attenuation of lumen (B30f/B36f, B30f/B60f, B36f/B46f, B36f/B60f, and B46f/B60f), oil (B30f/B36f, B30f/B46f, B30f/B60f, B36f/B46f, and B46f/B60f), calcium (all kernels), and plaque (B30f/B36f, B30f/B46f, B30f/B60f, and B46f/B60f) using 4 different kernels. The attenuation values (mean+/-SD) within the lumen (246+/-6, 215+/-13, 248+/-5, and 270+/-7), oil (-123+/-3, -127+/-1, -121+/-6, and -127+/-4), calcified plaque tissue (703+/-334, 739+/-364, 817+/-381, and 1181+/-503), and soft plaque tissue (134+/-56, 111+/-49, 120+/-56, and 102+/-41) showed high correlation (p<0.001) when attenuation of all structures were compared in different kernels.


CONCLUSIONS
Use of sharper convolution kernels significantly increases the attenuation of the calcium within coronary plaques and reduces the attenuation of soft plaque tissue.
Cademartiri
Filippo
F
Dipartimento di Radiologia, Erasmus Medical Cencter, Rotterdam, The Netherlands. filippocademartiri@hotmail.com
Runza
Giuseppe
G
Mollet
Nico R
NR
Luccichenti
Giacomo
G
Belgrano
Manuel
M
Somers
Pamela
P
Knaapen
Michiel
M
Verheye
Stefan
S
Bruining
Nico
N
Hamers
Ronald
R
Midiri
Massimo
M
De Feyter
Pim J
PJ
Krestin
Gabriel P
GP
D000368:Aged; D001344:Autopsy; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology; D003627:Data Interpretation, Statistical; D005260:Female; D006652:Histological Techniques; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed / Q000379:methods*