Duan Haifeng MMed, Presenter: Nothing to Disclose

Ma Guangming MMed, Abstract Co-Author: Nothing to Disclose

Zhang Xirong MMed, Abstract Co-Author: Nothing to Disclose

Yang Chuangbo MMed, Abstract Co-Author: Nothing to Disclose

Guo Youmin MD, Abstract Co-Author: Nothing to Disclose

Tian Qian MMed, Abstract Co-Author: Nothing to Disclose

Jia Yongjun MMed, Abstract Co-Author: Nothing to Disclose

To evaluate if the virtual nonenhanced (VNE) images generated from the contrast-enhanced spectral CT images could replace the true nonenhanced (TNE) for radiation dose reduction.

40 adults (28 males and 12 females, ages: 23-76 years) underwent 3-phase abdominal CT were retrospectively analyzed. Plain CT was performed with conventional 120kVp. The contrast-enhanced scans in the arterial phase (AP) and portal venous phase (VP) were performed with spectral CT imaging mode. VNE images were generated from the AP and VP spectral CT images. 2 board-certified radiologists reviewed both TNE and VNE images for image quality and lesion detection. Mean CT value, signal-noise-ratio (SNR) and contrast-noise-ratio (CNR) for liver, spleen, kidney, pancreas and muscle were measured. Lesion detection rate, subjective image rating and radiation dose were also assessed and compared.

Both the TNE and VNE images satisfied clinical needs for lesion detection and image quality. The image quality scores were 4.73±0.55, 4.25±0.90 and 4.55±0.64 for TNE, VNE at AP and VNE at PP, respectively, and there was no difference in terms of number of lesions detected (108, 100 and 104, respectively) (p>0.05). The mean and standard deviation values (in HU) of the CT number in liver, spleen, kidney, pancreas and muscle were, respectively, (53.16±6.11, 48.40±6.06, 36.84±9.41, 32.00±3.34 and 46.00±5.62) on TNE, (54.12±6.39, 50.79±5.06, 41.99±7.65, 34.34±4.62 and 48.22±5.90) on VNE at AP and (57.09±5.91, 53.80±3.98, 43.30±6.87, 34.08±3.68, and 49.16±6.19) on VNE at VP. There was slight bias for CT numbers on VNE. However, the absolute difference in CT number between VNE and TNE was less than 10HU, with the largest at VP for the pancreas. VNE at AP had better CT number fidelity with the smallest difference for the liver. CNR values in 3 groups were similar. VNE images provided statistically higher SNR. The potential dose reduction for replacing TNE with VNE was 21.4%.

VNE image generated from the contrast-enhanced abdominal spectral CT provides adequate image quality for lesion depiction, high CT number fidelity and 20% dose reduction compares with TNE.

VNE images generated from the contrast-enhanced abdominal spectral CT may be used to replace TNE images to provide adequate image quality for lesion depiction and 20% dose reduction.

Haifeng, D, Guangming, M, Xirong, Z, Chuangbo, Y, Youmin, G, Qian, T, Yongjun, J, Spectral CT Imaging in Abdominal Patients: Evaluation of Whether the Virtual Nonenhanced Images from Contrast-enhanced Spectral CT Could Replace Plain Scan for Radiation Dose Reduction.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016839.html