Obstruction / Occlusion, Contrast agent-intravenous, CT-Angiography, Pulmonary vessels
A. Demchenkova, T. N. Veselova, T. Martynyuk, N. Danilov, S. K. Ternovoy, I. E. Chazova, N. Serova; Moscow/RU
Methods and Materials
Between November 2015 and May 2016 were examined 22 patients with a definite diagnosis of CTEPH (7 men,
15 women; range,
All patients were examined on 320-detector row CT scanner (Aquilion ONE 640 VISION Edition,
Toshiba Medical Systems) using the standard protocol Lung substraction.
Scans have been acquired in the supine position,
in craniocaudal direction,
during breath-hold at the maximum depth of the breath in non-contrast and arterial phases with the same parameters in the beginning and in the end of the scan.
Contrast agent (70-80 ml) was administered intravenously at a rate of 5 ml/sec.
Scanning was performed in the arterial phase using automated contrast bolus tracking with a region of interest placed in the pulmonary trunk,
and automatically triggered start at 220 Hounsfield units.
Tube voltage and tube currency were 100-120 kV and 50-100 mA,
slice thickness 0.5 mm.
The average effective dose of radiation exposure was 8-10 mSv.
Quantification of perfusion defect was done using the new software that allows to perform the analysis of perfusion lung disorders in the first passage of the contrast agent through the right side of the heart,
pulmonary artery and its branches.
Combination of non-contrast and contrast images was obtained by using subtraction .
Calculation of CT angiographic obstruction score was performed according to the formula described Qanadli et al.: CT obstruction index = Σ (n·d) / 40x100,
where n is the number of segmental arteries with obstruction (minimum,
and d is the degree of vascular obstruction (minimum,
The arterial tree of each lung was represented as 10 segmental arteries (three in both upper lobes,
two in the middle lobe and the lingular division,
and five in both lower lobes) [2-4].
The perfusion defect score can be expressed as Σ (n·d) / 40x100,
where n is the number of segments with perfusion lung disorders and d is the degree of the perfusion defect from 0 to 2 points .
Color model was used to quantify the degree of the perfusion defect,
where the areas from yellow to red colors interpret as normal perfusion,
from purple to dark blue indicate reduced perfusion and from dark blue to black indicate total loss of perfusion,
basing on lung density.