Therefore, for cervical cancer, the suggested time interval for determining posttherapy treatment response with pelvic MRI is 3 to 6 months after completion of therapy [27], although earlier imaging is sometimes used for interim assessment of tumor regression for prognostication and/or adaptive radiation planning. Because MRI relies primarily on size criteria for nodal evaluation, it has limitations similar to CT with respect to sensitivity and specificity for nodal metastases. Therefore, although MRI may depict size regression of nodal metastases following therapy, it is likely at least modestly inferior for detecting new or residual disease in subcentimeter lymph nodes compared to FDG-PET/CT [22,23,29,30]. 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 gadolinium-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 MRI of the abdomen and pelvis can be considered in the early posttreatment evaluation of primary vaginal cancer, although its main value is in the utility of pelvic MRI for primary tumor response assessment. MRI of the abdomen is not commonly included, given the availability of whole-body FDG-PET/CT or CT of the chest, abdomen, and Staging and Follow-up of Primary Vaginal Cancer pelvis for evaluation of distant disease. Although no study has specifically evaluated pelvic MRI for treatment response assessment in vaginal cancer patients, multiple studies support its potential value in cervical cancer to which analogous principles apply.
Staging and Follow up of Primary Vaginal Cancer. Therefore, for cervical cancer, the suggested time interval for determining posttherapy treatment response with pelvic MRI is 3 to 6 months after completion of therapy [27], although earlier imaging is sometimes used for interim assessment of tumor regression for prognostication and/or adaptive radiation planning. Because MRI relies primarily on size criteria for nodal evaluation, it has limitations similar to CT with respect to sensitivity and specificity for nodal metastases. Therefore, although MRI may depict size regression of nodal metastases following therapy, it is likely at least modestly inferior for detecting new or residual disease in subcentimeter lymph nodes compared to FDG-PET/CT [22,23,29,30]. 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 gadolinium-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 MRI of the abdomen and pelvis can be considered in the early posttreatment evaluation of primary vaginal cancer, although its main value is in the utility of pelvic MRI for primary tumor response assessment. MRI of the abdomen is not commonly included, given the availability of whole-body FDG-PET/CT or CT of the chest, abdomen, and Staging and Follow-up of Primary Vaginal Cancer pelvis for evaluation of distant disease. Although no study has specifically evaluated pelvic MRI for treatment response assessment in vaginal cancer patients, multiple studies support its potential value in cervical cancer to which analogous principles apply.