Staging uterine cervical carcinoma with low-field MR imaging

Purpose: To assess the validity of low-field MR in staging cervical cancer compared to clinical staging. Material and Methods: A total of 95 women entered the study over a 3-year p eriod. MR examinations with a 0.1 T resistive magnet using a body coil and clinical staging according to the FIGO recommendations (1988) were performe d within 2 weeks from clinical diagnosis. T1- and T2-weighted sequences wer e obtained in transversal and sagittal acquisitions, and an additional T1 b efore and after contrast (randomisation to 0.1 or 0.3 mmol/kg b.w gadodiami de). Treatment decisions on surgery or radiation therapy were made solely o n the clinical staging. Results: Sixty-one patients were found to be eligible for surgery. In 5 wom en, the pathological results revealed a more advanced stage of the disease than assessed by clinical staging. MR correctly staged 4 of the 5 but other wise tended to overstate the disease. Contrast enhancement significantly re duced this trend (p<0.05) regardless of the contrast medium dose used. Divi ded into two groups, an operable (less than stage 2b) and an inoperable gro up (more than stage 2a), the clinical staging correctly classified 57 patie nts (accuracy 92%) compared to 52 patients with MR using contrast enhanceme nt (accuracy 84%). The specificity was no higher than 31%, whereas the repr oducibility of the MR assessment was fairly good with kappa values around 0 .65 for both intra- and inter-observer variations. Conclusion: In the present set-up, clinical assessment was superior to low- field MR in staging cervical cancer. When using contrast enhancement, the s taging accuracies of low-field MR were comparable to the ones reported for techniques with higher tesla values, whereas the specificity and reproducib ility errors were lower. The method, therefore, needs to be optimised.