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[Magnetic resonance imaging in the evaluation of parametrial invasion of carcinoma of the cervix uteri: optimization of the study protocol].

PURPOSE
To determine the efficacy of three different MR sequences in the evaluation of parametrial invasion by early-stage cervical cancer.


MATERIAL AND METHODS
Eighteen consecutive patients with cervical cancer clinically assessed as stage IB1 underwent MR imaging examination with the use of the following sequences: FSE T2-weighted, FSE fat-suppressed T2w, and SE fat-suppressed Gadolinium-enhanced T1w. In all cases, the presence or absence of parametrial invasion on both sides per each sequence used was evaluated. Subsequently all the sequences have been considered together for the evaluation of tumor invasion. Gold standard of the study was the histopathologic analysis of the surgical specimens.


RESULTS
At histological examination, parametrial invasion by tumor was found in 6 out of 36 parametria evaluated. The accuracy achieved with each of the sequences used was as follows: 94% with FSE T2w; 86% with FSE fat-suppressed T2w; and 67% with SE fat-suppressed Gadolinium-enhanced T1w. The simultaneous evaluation of all 3 sequences obtained an accuracy level similar to that achieved with FSE T2w. The difference between the accuracy of T2w sequences and that of fat-suppressed contrast-enhanced T1w sequences was statistically significant (p<0.01).


DISCUSSION AND CONCLUSIONS
Our data suggest that the MR imaging protocol for the evaluation of parametrial tumor invasion could be restricted to FSE T2w sequences. These proved to have the highest negative predictive value (97%) which allows a reliable selection of patients who can be surgically treated.