Comparison of Image Quality of Low Voltage 64-slice Multidetector CT Angiography with the Standard Condition in Patients Suspected of Pulmonary Embolism

Reduction of peak kilovoltage (kV) setting has been a useful approach to d creating radiation dose; however, it may have varied effects on noise and the accuracy of diagnosis. Thus, we compared image quality between low (80 kV) and standard kilovoltage (100 kV) protocols.
Material and This triple blind non-randomized parallel quasi-experimental study was conducted on 140 cases of questionable pulmonary embolism. Image quality was twice as high as the standard protocol in the 80-kV group (odds ratio=2.08). Main, segmental, and subsegmental arteries showed significantly higher vascular enhancement (P<0.001) in the 80-kV group. Similarly, the mean number of measurable segmental arteries was significantly greater in the 80-kV group relative to the standard group. On the other hand, the mean of image noise was significantly higher in the 80-kV group in comparison with the 100-kV group (mean: 68.4 vs. 43.1; P<0.001). Finally, the mean of radiation dose received in the 80-kV group was significantly lower than that in the 100-kV group (mean: 0.94 vs. 2.43 mSv; P<0.001). Lower radiation dose received and higher image quality, but worse image noise, in the 80-kV group compared to the 100-kV group present acceptable evidence in support of reduction of voltage in cases with the suspicion of pulmonary embolism. In these patients, therefore, it is recommended as a good strategy to be adopted in computed tomography angiography.