18F-FDG PET/CT and PET/MRI Perform Equally Well in Cancer

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  ¹⁸F-FDG PET/CT and PET/MRI Perform Equally Well in Cancer: Evidence from Studies on More Than 2,300 Patients

Gynecologic Cancer

Uterine, ovarian, and cervical cancer is initially diagnosed by ultrasound or biopsy. CT, MRI, and PET/CT are suggested for additional work-up if there is suspected or gross cervical involvement and suspected extrauterine disease (51,52).

Diagnostic accuracy was similar between PET/CT and PET/MRI for detection of primary and recurrent pelvic malignancies in 3 studies that included a total of 69 patients (Table 4) (53–55). In the first study, on 19 patients with recurrent gynecologic cancer, both modalities correctly identified all 58 malignant lesions (57 of which were ¹⁸F-FDG–positive), including local and distant sites of recurrence (53). The diagnostic accuracy of PET/MRI and PET/CT on a patient basis was thus identical. The soft endpoint, interpreter confidence, appeared to be higher for PET/MRI than for PET/CT in both malignant (P < 0.01) and benign lesions (P < 0.05) (53).

In the second study, on 26 patients, both modalities accurately identified all primary and recurrent tumors and abdominal metastases (54). Lesion conspicuity was better for PET/MRI (dedicated pelvic sequences) than for enhanced PET/CT.

In the third study, Grueneisen et al. restaged 24 patients with a variety of gynecologic cancers (55). According to the reference standard (histopathology and imaging follow-up), 21 of those 24 patients (88%) had tumor recurrence. Both PET/CT and PET/MRI correctly identified 20 of 21 patients (95%) with tumor relapse.

In summary, in the 69 patients with gynecologic cancer, diagnostic accuracy was comparable between the two modalities (Table 4).