The Clinical Application Of Naturally Breathing And High-pitch Mode Computed Tomography Pulmonary Angiography With Dual-source Scanner

Objective:To investigate the feasibility of naturally breathing high-pitch mode computed tomography pulmonary angiography (CTPA) with dual-source scanner in patients with suspected pulmonary embolism.Methods:After110patients with clinically suspected pulmonary embolism were underwent computed tomography pulmonary angiography (CTPA) with the second generation of dual-source CT, the patients were randomly divided into2groups:High-pitch group (n=55), CTPA in high-pitch mode (pitch3.0,100kV,100mAs, contrast material40mL) without naturally breathing. Routine group (n=55),CTPA in normal mode (pitch0.8,120kV,100mAs, contrast material80mL) scanning in the end of spiratory and breath-hold. Pulmonary trunk, apical segment (S1) and posterior basal segment (S10) artery enhancement, image noise, signal to noise ratio(SNR), CT dose index volume(CTDIvol in mGy), dose-length product(DLP in mGy cm), effective dose(ED) and subjective image quality grade were compared between the two groups. The statistic analysis were done with SPSS19.0, and Student t test, Chi-Square test, Mann-Whitney U test, Kappa test were employed.Results:For mean pulmonary trunk attenuation, The high-pitch group(421±107) was higher than the routine group(375±113)(p<0.05); SNRsi (41.63±9.26)and SNRsi0(41.31±9.13) of the high-pitch group was significantly higher than SNRs1、SNRs10(33.24±10.23±35.20±11.11) of the routine group(p<0.01), Mean image noise(10.05±1.53), Mean examination time(0.76±0.07) of the high-pitch group was significantly lower than the routine groups<0.01), Mean CTDIVOi (2.88±0.44), mean DLP(88±14), mean ED(1.50±0.23) of the high-pitch group was significantly lower than the routine group (5.61±0.98mGy,144±30mGy*cm,2.45±0.52mSv)(p<0.01). for the overall image quality scores, The high-pitch group was higher than the routine group(p <0.05). In the high-pitch group, There were no motion artifacts of the diaphragm or pulmonary vessels related to breathing or heart motion, There was no case of partial or total interruption of the contrast column in the PA tree, No examination was rated non-diagnostic.Conclusions:High-pitch mode CTPA with dual-source scanner in freely breathing can produces images that are free of artifacts related to breathing and cardiac motion. To meet the requirements for the diagnosis of pulmonary embolism, it is of particular value for the severe, shortness of breath, difficult to hold breath patients during CTPA examination. Radiation dose and iodine load can also be decrease using this technique.