AIM
To evaluate the impact of different b-value combinations on synthetic diffusion-weighted imaging (sDWI) and determine the sDWI with an optimal b-value combination for prostatic cancer (PCa) diagnosis.
MATERIAL AND METHODS
A retrospective analysis of 68 patients with abnormal prostate-specific antigen (PSA) was conducted. The sDWI images with b value of 1500 s/mm2 were separately reconstructed by the following five b-value combinations: b=0, 200s/mm2 (sDWI0-200); b=600, 800s/mm2 (sDWI600-800); b=0, 600s/mm2 (sDWI0-600); b=200, 800s/mm2 sDWI200-800); b=0, 800s/mm2 (sDWI0-800). Quantitative analysis was performed on the acquired DWI (aDWI) images with b=1500s/mm2 (aDWI1500) and all sDWI images. These six image groups were scored in five aspects for image quality and further reviewed by two radiologists via six protocols: Protocol Ⅰ, T2WI+sDWI0-200; Protocol Ⅱ, T2WI+sDWI600-800; Protocol Ⅲ, T2WI+sDWI0-600; Protocol Ⅳ, T2WI+sDWI200-800; Protocol Ⅴ, T2WI+sDWI0-800; Protocol Ⅵ, T2WI+aDWI1500. The corresponding diagnostic efficacies for PCa were evaluated using receiver operating characteristic (ROC) curves.
RESULTS
Contrast ratio values of all sDWI images were higher than those of aDWI1500 images. Contrast-to-noise ratio values of sDWI0-200 and sDWI600-800 images were lower than those of the rest sDWI images. All subjective quality scores of sDWI0-600, sDWI200-800, and sDWI0-800 were significantly higher than other groups except for background signal suppression. The area under the curve (AUC) of Protocol Ⅲ, Ⅳ, Ⅴ, and Ⅵ was significantly larger than those of other protocols.
CONCLUSION
Different b-value combinations impact the image quality and diagnostic accuracy of sDWI for PCa detection. The combination of b≤200s/mm2 and b≥600s/mm2 revealed to be optimal.