Plaque imaging with CT coronary angiography: Effect of intra-vascular attenuation on plaque type classification.
OBJECTIVE
To assess the attenuation of non-calcified atherosclerotic coronary artery plaques with computed tomography coronary angiography (CTCA).


METHODS
Four hundred consecutive patients underwent CTCA (Group 1: 200 patients, Sensation 64 Cardiac, Siemens; Group 2: 200 patients, VCT GE Healthcare, with either Iomeprol 400 or Iodixanol 320, respectively) for suspected coronary artery disease (CAD). CTCA was performed using standard protocols. Image quality (score 0-3), plaque (within the accessible non-calcified component of each non-calcified/mixed plaque) and coronary lumen attenuation were measured. Data were compared on a per-segment/per-plaque basis. Plaques were classified as fibrous vs lipid rich based on different attenuation thresholds. A P < 0.05 was considered significant.


RESULTS
In 468 atherosclerotic plaques in Group 1 and 644 in Group 2, average image quality was 2.96 ± 0.19 in Group 1 and 2.93 ± 0.25 in Group 2 (P ≥ 0.05). Coronary lumen attenuation was 367 ± 85 Hounsfield units (HU) in Group 1 and 327 ± 73 HU in Group 2 (P < 0.05); non-calcified plaque attenuation was 48 ± 23 HU in Group 1 and 39 ± 21 HU in Group 2 (P < 0.05). Overall signal to noise ratio was 15.6 ± 4.7 in Group 1 and 21.2 ± 7.7 in Group 2 (P < 0.01).


CONCLUSIONS
Higher intra-vascular attenuation modifies significantly the attenuation of non-calcified coronary plaques. This results in a more difficult characterization between lipid rich vs fibrous type.
Erica Maffei, Chiara Martini, Teresa Arcadi, Filippo Cademartiri, Cardiovascular Imaging Unit, Giovanni XXIII Hospital, 31050 Monastier di Treviso, Treviso, Italy.
Erica
E
Maffei
Chiara
C
Martini
Teresa
T
Arcadi
Alberto
A
Clemente
Sara
S
Seitun
Alessandra
A
Zuccarelli
Tito
T
Torri
Nico R
NR
Mollet
Alexia
A
Rossi
Onofrio
O
Catalano
Giancarlo
G
Messalli
Filippo
F
Cademartiri