The classic staging of cervical cancer is clinical and uses the International Federation of Gynecology and Obstetrics (FIGO) classification. In addition to the standard physical examination, FIGO staging may include findings from physical examination under anesthesia, cystoscopy, rectosigmoidosccopy, barium enema, biopsy, intravenous pyelography, and chest radiography. However, when compared with intraoperative and pathologic findings, FIGO clinical staging shows errors of 20 to 66% depending on the stage of the disease. In addition, FIGO staging does not take into account important prognostic factors such as tumor volume and the presence and extent of nodal involvement. The real strength of MRI is its ability to exclude parametrial invasion, because the presence of parametrial invasion makes radiation therapy rather than surgery the preferred treatment. Unfortunately, the positive predictive value of MR imaging for the diagnosis of parametrial invasion is only 67%. Direct lateral extension of tumor into the parametrium is usually easily recognized, however, cervical cancer can demonstrate several patterns of spread including: local intracervical extension with forniceal obliteration but without invasion, extension into the wall of the fornices, vagina, or both, protrusion into the vaginal lumen, and extension into the paracolpium, lower parametrium, or both. Differentiation of these various patterns of tumor extension is possible only if the morphology of the vaginal and forniceal walls can be assessed. This may be difficult in the physiologic state, as the lumen of the vagina and fornices is usually collapsed. MR imaging with intravaginal contrast has been developed as a possible solution to address this problem.
Vaginal distension improves assessment of the cervix and adjacent vaginal mucosa. Vaginal lubricant is used to distend the vagina and to outline the cervix for complete assessment of the female pelvis when required. In our institution, the major indications for application of vaginal gel include cervical cancer (initial evaluation or follow-up after treatment), cervical mass, and vaginal mass. In addition, this technique can also be used in patients with vaginal atrophy and when distortion of normal anatomy occurs in the setting of large pelvic masses where the cervix may become compressed and/or displaced. Without distension, apposition of the mucosa within the vaginal fornices can mimic a mass, especially when this signal blends with the signal intensity of the surrounding vessels. In addition, differentiation of various patterns of tumor extension, e.g. cervical cancer with spread into the parametrium, is possible only if the morphology of the vaginal and forniceal walls can be assessed. Studies have shown that vaginal opacification in patients with cervical cancer has resulted in an improved visualization of the vaginal wall, lumen, and fornices and have improved the visualization of the tumor, parametrium infiltration, and bladder and rectal invasion, thus modifying staging of cervical cancer in patients.
Vaginal Gel Contrast
For opacification of the vagina our department uses surgical lubricant (Surgilube from Fougera). Other studies have used mixtures of maltodextrin/calcium lactate, water, and barium. The patient is put on the MR table and given two 10cc syringes filled with Surgilube. After the procedure is explained to the patient, the patient is given privacy to insert as much Surgilube into her vagina. Following insertion of the contrast material, the patient in a supine position and the MRI coils are set up. MR images are obtained using a routine protocol for female cervix imaging, which includes non-enhanced T1-weighted images in the axial plane, T2-weighted images in the axial, sagittal, and coronal planes, and T1-weighted contrast-enhanced 3D GRE images with fat saturation (VIBE).
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