However, data from mixed cohorts of patients with recurrence of cervical, vaginal, and other gynecologic cancers have suggested superior sensitivity of FDG-PET/CT for pelvic nodal metastases compared with pelvic MRI and CT [29,30]. The use of IV contrast may improve tissue characterization but is not considered essential, with variable inclusion in published protocols for evaluation of vaginal [28,31] and cervical cancer [7,32-34]. No study has specifically compared the incremental utility of contrast-enhanced sequences over T2-weighted sequences for pelvic MRI in this context. Regarding the use of vaginal gel in MRI of the pelvis, there is insufficient primary data in the literature to support its routine use. MRI Abdomen and Pelvis Because of the rarity of vaginal cancer, the primary data regarding the use of MRI in initial staging of vaginal cancer are sparse. Taylor et al [28] retrospectively evaluated pelvic MRI for initial staging in 25 patients with primary vaginal cancer spanning all disease stages. MRI depicted the primary tumor in 96% (24 of 25) of patients, demonstrating hyperintense signal compared to muscle on T2-weighted images, and enabled assignment of a radiologic disease stage based on adaptation of FIGO clinical staging criteria. Because 80% (20 of 25) of patients received either radiation or palliative therapy, pathologic confirmation of imaging findings could be obtained in only 20% (5 of 25) of cases. Of these cases, MRI stage was concordant with pathologic stage in 40% (2 of 5). More recent data in cervical cancer patients support the use of MRI for initial staging, with a meta-analysis suggesting high sensitivity (76%) and specificity (94%) of MRI for parametrial invasion [20]. Although MRI readily depicts lymph nodes, it has constraints similar to CT with regard to the limited sensitivity and specificity of size and morphologic criteria.
Staging and Follow up of Primary Vaginal Cancer. However, data from mixed cohorts of patients with recurrence of cervical, vaginal, and other gynecologic cancers have suggested superior sensitivity of FDG-PET/CT for pelvic nodal metastases compared with pelvic MRI and CT [29,30]. The use of IV contrast may improve tissue characterization but is not considered essential, with variable inclusion in published protocols for evaluation of vaginal [28,31] and cervical cancer [7,32-34]. No study has specifically compared the incremental utility of contrast-enhanced sequences over T2-weighted sequences for pelvic MRI in this context. Regarding the use of vaginal gel in MRI of the pelvis, there is insufficient primary data in the literature to support its routine use. MRI Abdomen and Pelvis Because of the rarity of vaginal cancer, the primary data regarding the use of MRI in initial staging of vaginal cancer are sparse. Taylor et al [28] retrospectively evaluated pelvic MRI for initial staging in 25 patients with primary vaginal cancer spanning all disease stages. MRI depicted the primary tumor in 96% (24 of 25) of patients, demonstrating hyperintense signal compared to muscle on T2-weighted images, and enabled assignment of a radiologic disease stage based on adaptation of FIGO clinical staging criteria. Because 80% (20 of 25) of patients received either radiation or palliative therapy, pathologic confirmation of imaging findings could be obtained in only 20% (5 of 25) of cases. Of these cases, MRI stage was concordant with pathologic stage in 40% (2 of 5). More recent data in cervical cancer patients support the use of MRI for initial staging, with a meta-analysis suggesting high sensitivity (76%) and specificity (94%) of MRI for parametrial invasion [20]. Although MRI readily depicts lymph nodes, it has constraints similar to CT with regard to the limited sensitivity and specificity of size and morphologic criteria.