Automated Tube Voltage Adaptation in Combination with Advanced Modeled Iterative Reconstruction in Thoracoabdominal Third-Generation 192-Slice Dual-Source Computed Tomography: Effects on Image Quality and Radiation Dose

Rationale and Objectives: To evaluate image quality and radiation exposure of portal venous-phase thoracoabdominal third-generation 192-slice dual-source computed tomography (DSCT) with automated tube voltage adaptation (TVA) in combination with advanced modeled iterative reconstruction (ADMIRE). Materials and Methods: Fifty-one patients underwent oncologic portal venous-phase thoracoabdominal follow-up CT twice within 7 months. The initial examination was performed on second-generation 128-slice DSCT with fixed tube voltage of 120 kV in combination with filtered back projection reconstruction. The second examination was performed on a third-generation 192-slice DSCT using automated TVA in combination with ADMIRE. Attenuation and image noise of liver, spleen, renal cortex, aorta, vena cava inferior, portal vein, psoas muscle, and perinephric fat were measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Radiation dose was assessed as size-specific dose estimates (SSDE). Subjective image quality was assessed by two observers using five-point Likert scales. Interobserver agreement was calculated using intraclass correlation coefficients (ICC). Results: Automated TVA set tube voltage to 90 kV (n = 8), 100 kV (n = 31), 110 kV (n = 11), or 120 kV (n = 1). Average SSDE was decreased by 34.9% using 192-slice DSCT compared to 128-slice 120-kV DSCT (7.8 +/- 2.4 vs. 12.1 +/- 3.2 mGy; P < .001). Image noise was substantially lower; SNR and CNR were significantly increaeed in 192-slice DSCT compared to 128-slice DSCT (all P < .005). Image quality was voted excellent for both acquisition techniques (5.00 vs. 4.93; P = .083). Conclusions: Automated TVA in combination with ADMIRE on third-generation 192-slice DSCT in portal venous-phase thoracoabdominal CT provides excellent image quality with reduced image noise and increased SNR and CNR, whereas average radiation dose is reduced by 34.9% compared to 128-slice DSCT.