Keywords:
Ear / Nose / Throat, Head and neck, Thorax, CT, CT-Quantitative, Computer Applications-3D, Computer Applications-Virtual imaging, Chronic obstructive airways disease, Acute
Authors:
Z. Ding, Z. Wang; Hangzhou/CN
DOI:
10.1594/ecr2013/B-0271
Methods and Materials
Sixteen patients with small BMI (BMI < 25) underwent 640-slice dynamic volume CT scan (80 or 100kV; 50 mA; collimation,
320×0.5 mm; gantry rotation,
0.5 second; acquisition time,
3-6 seconds).
Eight patients employed 100kv protocol,
acquisition time,
5.1 seconds; and remaining 8 objects employed 80kv protocol,
acquisition time,
5.2 seconds.
During the coaching period,
expiratory time (Texp) taken from maximal end-inspiration to the end of forceful exhalation was measured,
and acquisition time was selected according to Texp time.
Multiplanar reformation and 3D reconstruction images were created from each respiratory phase of the 16 CT acquisitions.
All images were reviewed in a randomized,
blinded fashion by two experienced radiologists,
who measured the tracheal lumen to determine the presence of central airways narrowing by consensus.
The 3D reconstruction images of confidence level in measuring the tracheal lumen was graded on a four-point scale from 0 (no confidence) to 3 (highest level of confidence),
also by consensus of the two same radiologists.
The multiplanar reformation image noise level was assessed by measuring the standard deviation of the pre-sternal soft tissue.
The radiation doses were recorded for each type of scan,
and the relative radiation dose length products were used to compare radiation doses of the various CT techniques.