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

yuanfen liu, Abstract Co-Author: Nothing to Disclose

To investigate the clinical value of using a Gemstone spectral imaging(GSI) protocol with 50% adaptive statistical iterative reconstruction (ASiR) and lower contrast injection rate (3ml/s) in carotid CTA by comparison with a conventional 120-kVp protocol with normal contrast injection rate (5ml/s).

With local ethical committee approval, 41 patients were prospectively enrolled in the study: 21 were scanned with parameters of 120 kVp, 240 mAs, contrast medium (CM) of 320 mg I/mL with 5ml/s injection rate in group A, and the other 20 were scanned with GSI mode, 315 mAs, 50% ASiR using the same CM with 3 ml/s injection rate in group B. Monochromatic images of 60keV were evaluated in GSI group. Image quality (IQ) of the two groups was compared in terms of arterial enhancement, 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.

Both carotid (9.78±2.88HU) and three main branches of thoracic aorta (19.05±6.40HU) showed lower image noise in GSI (50% ASiR, 3ml/s) than that of 120-kVp group (26.69±4.68HU) (P<0.05, respectively). The artery enhancement, 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 ED and contrast dose of GSI group (2.86±0.07mSv, 49.42±8.91ml) was 10.9% and 26.79% lower than that of 120-kVp group (3.21±0.30mSv, 67.5±13.72ml), respectively. There was significant difference statistically in ED and contrast dose, respectively, between two groups (all of them P<0.05).

The use of spectral imaging with 50% ASiR and injection rate of 3ml/s could provide lower image noise of both carotid and three main branches of thoracic aorta arteries than that of 120-kVp scan and provide higher image quality than that of 120-kVp protocol with a smaller amount of iodine and a lower radiation dose.

GSI low keV monochromatic imaging can improve the effect of enhancement and thus reducing the amount of contrast agent, in addition, combined with ASiR, it can decrease the noise of images, improve image quality and reduce the scanning of GSI dose.

Xue, Y, Duan, Q, Wei, J, LIN, L, liu, y, Spectral Imaging Associated with Lower Contrast Injection Rate for Carotid Artery: Initial Clinical Experience.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045536.html