Low-kilovoltage, high-tube-current MDCT of liver in thin adults: pilot study evaluating radiation dose, image quality, and display settings.

Objective: The purpose of our study was to evaluate the effect of a low tube voltage-high tube current-time product technique for portal phase abdominal CT of thin adults.

Subjects And Methods: This study included 25 patients who had undergone portal phase abdominal CT at 120 kVp in the preceding 6 months. All were scanned using 80 kVp and high tube-current time products. We assessed the estimated effective dose (ED), image noise, attenuation, contrast-to-noise ratio (CNR), and figure of merit of the liver and portal vein. Two radiologists evaluated the quality of scans for image contrast and streak artifacts at 80 kVp, 120 kVp, and 80 kVp with wide window width display presets (W-80).

Results: The estimated ED was 33% lower at 80 than at 120 kVp. CNR of the portal vein was 36.8% higher at 80 than 120 kVp, and for the liver it was 17.7% higher at 80 than 120 kVp. The visual score of image contrast was significantly higher for W-80 than for 120 kVp; however, there was no significant difference in the visual score of streak artifacts.

Conclusion: At portal phase abdominal CT, 80 kVp and a high tube current-time product setting significantly improved image quality and reduced the radiation dose compared with 120 kVp.