Preoperative MR staging of cervical carcinoma: are oblique and contrast-enhanced sequences necessary?

BACKGROUND As the choice of treatment in patients with cervical carcinoma depends on cancer stage at diagnosis, accurate staging is essential. PURPOSE To compare three different combinations of magnetic resonance (MR) sequences for preoperative staging. MATERIAL AND METHODS Fifty-seven consecutive patients with biopsy proven cervical carcinoma underwent MR imaging (MRI) staging followed by primary surgical treatment. Thirty-two of 57 patients had had a cone biopsy prior to MRI. Three MR pulse sequence combinations were retrospectively reviewed by two experienced radiologists. The first imaging protocol consisted of pre-contrast sagittal and transverse images (protocol A), the second protocol included additionally oblique high-resolution T2-weighted (T2W) MR images of the cervix (protocol A+B), and the third included also contrast-enhanced sequences (protocol A+B+C). The imaging findings in the three steps (A, A+B, A+B+C) were recorded. The TNM stage was used for comparison between preoperative imaging and histopathology. Histopathology, together with surgical findings, served as gold standard. RESULTS In 4/57 (7%) patients, the MR assessment of tumor stage (mrT) was altered when oblique sequences were added to the standard two plane imaging protocol (A+B). The mrT stage was altered in 1/57 (2%) patient when contrast-enhanced sequences were added to standard and oblique sequences (protocol A+B+C). The correlation between visible tumor on MRI and presence of tumor in the resected specimen did not change by adding oblique or contrast-enhanced images. CONCLUSION It is not necessary to perform oblique and contrast-enhanced sequences in small cervical carcinomas, i.e. without parametrial invasion. To avoid erroneous interpretation, information on previous cone biopsy is essential.