OBJECTIVETo evaluate the validity of whole body diffusion-weighted imaging (WBDWI) for the detection of malignant lesions.

METHODSNine healthy volunteers, 4 postoperative cases of malignant tumor and 16 malignant tumor cases were included in this study. 29 cases underwent whole body diffusion-weighted imaging on GE Signa Excite HD MR scanner within one week after or before PET examination. The images were double-blindly evaluated by two radiologists without the knowledge of the original PET results. Clinical diagnoses of malignant lesions were mainly based on PET results taken as gold standard. The malignant lesions were evaluated according to nine locations: lymph node; central nervous system; lung; liver, gallbladder, pancreas and spleen; digestive tract; kidney and adrenal gland; pelvic; skeleton, and soft tissue of each subject. The sensitivity, specificity, positive predicative value, negative predicative value, Youden's index and likelihood ratio of WBDWI were analyzed.

RESULTSThe images of all the 9 healthy volunteers were normal. 57 malignant lesions were found in the 20 malignant cases by PET, among whom 48 lesions were detected by WBDWI including 2 false positive lesions. Among the 261 locations of 29 cases, the WBDWI examination showed 21 true positive locations, 2 false positive locations and 3 false negative locations. The sensitivity, specificity, positive predicative value, negative predicative value, Youden's index and likelihood ratio of WBDWI were 87.5%, 99.2%, 91.3%, 98.7%, 86.7%, and 103.7, respectively.

CONCLUSIONThe validity of WBDWI is high, and it could be a new whole body imaging technique for staging of malignant tumors.