Yunjing Xue MD, Presenter: Nothing to Disclose

Qing Duan MD, Abstract Co-Author: Nothing to Disclose

Jin Wei, Abstract Co-Author: Nothing to Disclose

Lin LIN, Abstract Co-Author: Nothing to Disclose

To investigate the clinical value of using a 100-kVp protocol with 50% adaptive statistical iterative reconstruction (ASiR) and with lower contrast injection rate (4ml/s) in carotid CTA by comparison with a conventional 120-kVp protocol with normal contrast injection rate (5ml/s).

With local ethical committee approval, 43 patients were prospectively enrolled in the study: 21 were scanned with parameters of 120 kVp, 240 mAs, using contrast medium (CM) of 320 mg I/mL with 5ml/s injection rate, and the other 22 were scanned with 100 kVp, 288 mAs, 50% ASiR using the same contrast of 4ml/s injection rate. Image quality (IQ) of the two groups was compared in terms of HU of enhanced arterial, noise, signal-noise-ratio (SNR) and contrast-to-noise ratio (CNR). The effective dose (ED) of radiation and contrast dose were calculated and compared. Data were analyzed by using Independent samples t test.

The carotid artery in 100-kVp (50% ASiR, 4ml/s) group (443.28±72.58HU) demonstrated higher enhancement than that of 120-kVp group (376.60±62.42HU), (P<0.05). Both carotid and three main branches of thoracic aorta showed lower image noise in 100-kVp (11.31±2.20HU, 19.21±3.61HU) than that of 120-kVp group (14.29±2.81HU, 26.69±4.68HU), (P<0.05, respectively). The CNR and SNR of carotid artery and three main branches of thoracic aorta has no significant differences statistically between two groups (all of them P>0.05), respectively. The effective dose and contrast dose of the 100-kVp with 4ml/s protocol (2.38±0.002 mSv, 58.80±9.81ml ) was 25.86% and 12.89% lower than that of the 120-kVp with 5ml/s protocol (3.21±0.30 mSv, 67.5±13.72 ml), respectively. There was significant difference statistically in effective dose of radiation and contrast dose between two groups (P<0.05), respectively.

The use of 100 kVp with 50% ASiR and lower injection rate of CM could provide higher artery enhancement and superior image quality than that of 120-kVp protocol with a smaller amount of iodine and a lower radiation dose.

A low tube voltage with ASiR technique and lower injection rate has a potential clinical application prospect by moderately decreasing radiation and contrast agent doses with superior image quality at carotid CTA.

Xue, Y, Duan, Q, Wei, J, LIN, L, CT Angiography of the Carotid Arteries: Comparison of Lower-tube-Voltage CTA with Lower Iodinated Contrast Injection Rate and Conventional CTA.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008338.html