Evaluation of magnetic resonance diffusion and spectroscopy measurements as predictive biomarkers in stage 1 cervical cancer

ObjectiveTo establish whether ADC and total choline were significantly different between cervical tumors with different histological characteristics (type, degree of differentiation, presence or absence of lymphovascular invasion, lymph-node involvement) in order to establish their role as predictive biomarkers.Methods62 patients with stage 1 cervical cancer were scanned at 1.5 T. T2-weighted imaging (TR/TE = 4500/80 ms), to identify tumor and normal cervix, was followed by diffusion-weighted imaging (TR/TE = 2500/69 ms; 5 b-values 0, 100, 300, 500 and 800 s/mm2) and MR spectroscopic imaging (15 mm slice, 7.5 mm in-plane resolution, TR = 888 ms). Regions of interest in normal cervix and tumor were drawn on apparent diffusion coefficient (ADC) maps by an expert observer with reference to the T2-weighted images. ADCs were calculated using a monoexponential fit of data from all b-values. MR spectra in voxels designated as tumor (> 30% tumor) or non-tumor were quantified using LCModel and referenced to tissue water.ResultsThere was a statistically significant difference between the ADC of tumor regions (1117 ± 183 × 10− 6 mm2/s) and of selected normal regions (1724 ± 198 × 10− 6 mm2/s; p < 0.001), and between tumors that were well/moderately differentiated (1196 ± 181 × 10− 6 mm2/s) compared with those that were poorly differentiated (1038 ± 153 × 10− 6 mm2/s; p = 0.016). There was no significant difference between the ADCs of the tumors when separated by other characteristics (tumor type, lymphovascular invasion, lymph-node metastases), or between measured total choline in any of the groups.ConclusionADCs are lower in cancer compared to normal cervical tissue, with degree of tumor differentiation contributing to this difference.