Diagnostic accuracy in gynecological malignant tumors: A comparison between PET/CT and PET/MRI fusion images

Objectives MRI has better tissue contrast than CT. Therefore, we speculated that FDG-PET/MRI is better than PET/CT. The aim of the present study is to compare a diagnostic accuracy in gynecological malignancies between FDG PET/CT and PET/MRI fusion images.

Methods 25 patients with cervical carcinoma, 3 patients with endometrial carcinoma, and 3 patients with ovarian carcinoma were enrolled . 21 patients were studied before any treatments, and others had some therapy. To assess the ability of mapping images for PET, CT(of PET/CT), T1- and T2-weighted MR images(all non-contrast) were graded regarding the pelvic malignant lesions with a 5-point confidence scale(1=definitely absent to 5=definitely present).Fused PET/CT, PET/T1 or T2 MR images, generated with a dedicated software, were evaluated if additional diagnostic information to PET alone,such as lesion characterization, was obtained using a 3-point scale(1=no to 3=significantly added).Two nuclear medicine physicians visually inspected . Wilcoxon Matched-Pair Signed-Rank Test was employed for statistics.

Results Five points rating scale indicated that T2WI (4.5+/-0.8) is significantly superior in lesion detection than CT (3.3+/-0.9) or non-contrast T1WI (3.4+/-0.9) (p<0.01). Three point rating scale revealed that PET/T2WI (2.9+/-0.4) localized the lesion significantly more convincingly than PET/CT (2.2+/-0.6) or PET/T1WI (2.2+/-0.6) (p<0.01).

Conclusions PET/T2WI is superior to PET/CT or PET/non-contrast T1WI in detecting and localizing gynecological malignancies.