Image quality in dual-source multiphasic dynamic computed tomography of the abdomen: evaluating the effects of a low tube voltage (70 kVp) in combination with contrast dose reduction

Purpose

To compare the image quality of multiphasic (arterial, portal, and equilibrium phases) dynamic computed tomography (CT) of the abdomen obtained by a low tube voltage (70kVp) in combination with a half-dose iodine load using low-concentration contrast agent in high tube output dual-source CT with a standard tube voltage (120kVp) and full-dose iodine load using the same group of adult patients.

Methods

Fifty-five patients who underwent both low-tube-voltage (70kVp) abdominal CT with a half-dose iodine load and standard-tube-voltage (120kVp) CT with a full-dose iodine load were analyzed. The mean CT values and signal-to-noise ratio (SNR) of the liver, aorta and portal veins were quantitatively assessed. In addition, the contrast enhancement of the abdominal organs and overall image quality were qualitatively evaluated.

Results

The mean CT values and SNR of the liver parenchyma were significantly higher in 70-kVp protocol than in 120-kVp protocol in all 3 phases (p = 0.018 ~  < 0.001). Regarding the qualitative analysis, the overall image quality in the 70-kVp protocol was significantly better than in the 120-kVp protocol in all 3 phases (p < 0.001). In addition, the contrast enhancement scores of the liver parenchyma and hepatic vein in the equilibrium phase were also significantly higher in the 70-kVp protocol than in the 120-kVp protocol (p < 0.001).

Conclusion

A low tube voltage (70kVp) in combination with a half-dose iodine load using a low-concentration contrast agent and an iterative reconstruction algorithm in high tube output dual-source CT may improve the contrast enhancement and image quality in multiphasic dynamic CT of the abdomen in patients under 71 kg of body weight.