Keywords:
Embolism / Thrombosis, Contrast agent-intravenous, CT-Angiography, CT, Vascular, Thorax, Arteries / Aorta
Authors:
K. N. Jeon, K. Bae, S. B. Cho, S. Park, J. I. Moon, H. J. Baek, B. H. Choi, K. H. Ryu; Changwon/KR
Results
Sufficient attenuation of pulmonary artery (> 180 HU) was achieved in 40/41 (97.6%) patients at 40-70 keV (Fig 1).
The mean attenuation of the pulmonary artery on the VMIs at 40–65 keV was significantly (p < 0.001) higher than that on the conventional 120-kVp
image (Fig 2).
Noise levels of VMIs were gradually increased with decreasing keV.
The mean background noise at 40–65 keV was significantly (p < 0.05) higher than that at 120 kVp (Fig 3).
The mean background noises at 70 keV was not significantly different from that at 120 kVp.
CNR and SNR of VMIs at 40-65 keV were significantly (both p < 0.001)
higher than those of 120-kVp images (Fig 4 and Fig 5). The mean CNR and SNR at 70 keV was not significantly different from that at 120 kVp.The CNR was the highest at 40 keV for all cases.
VMI at 40 keV showed the highest SNR for 38 of 41 patients; the highest SNR was at 45 keV for the remaining three patients.
Subjective image quality was not significantly different between conventional
120-kVp and 40-keV images (Table 2).
Diagnostic accuracy for detecting PE calculated on a per-segment basis was was significantly higher for 40-keV images (reader 1: AUC = 0.992,
p = 0.033; reader 2: AUC = 0.986,
p = 0.043) than that for 120-kVp images (reader 1,
AUC = 0.911; reader 2,
AUC = 0.933) (Fig 6 and Fig 7).