Metabolite changes in the transition from pre-invasive to invasive cervical cancer using in vivo magnetic resonance spectroscopy


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Sonali De Silva, Geoffrey Payne, Veronica Morgan, John Shepherd, Thomas Ind, Desmond Barton, Nandita deSouza

Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, UK

Abstract

Aim

To investigate metabolite changes in the transition from pre-invasive to invasive cervical cancer using in vivo 1H magnetic resonance spectroscopy.

Method

37 women (16 cervical intraepithelial neoplasia (CIN), 3 microinvasive and 18 invasive cervical cancer proven histologically) were studied. A ring-design endovaginal coil of solenoid geometry was positioned around the cervix. Vaginal air, introduced during coil placement, was aspirated to reduce B0 inhomogenities. Studies were performed at 1.5T. Cervical tumour was delineated on T2-weighted images. 1H spectroscopic imaging was performed localised to the cervix using the PRESS technique (TR/TE 888/135ms, 4 signal averages, 17mins). Total Choline (tCho) peak was set as 3.2ppm and peak area measured using LCMODEL software. Tissue water from the same voxel was used as an internal standard. Spectral analysis was done on tumour voxels (>50% tumour), stromal voxels (>50% stroma, no tumour) and epithelium (>50% epithelium, no tumour). Independent two-sample t-tests adjusted for multiple comparisons were used to identify significant differences between individual groups.

Results

tCho/water ratio was significantly increased in tumour voxels (6.7±2.7) compared to epithelium voxels from CIN patients (4.6±1.8, p=0.021). A significant increase in tCho was observed in epithelial and stromal voxels adjacent to invasive cancer compared to voxels adjacent to CIN (p=0.012). tCho values in microinvasive disease were higher than in CIN but small patient numbers and high standard deviation meant results were not statistically significant.

Conclusion

tCho/ water ratio increases significantly between CIN and tumour voxels and shows potential as an indicator of the transition to invasive disease.

Aim

To investigate metabolite changes in the transition from pre-invasive to invasive cervical cancer using in vivo 1H magnetic resonance spectroscopy.

Method

37 women (16 cervical intraepithelial neoplasia (CIN), 3 microinvasive and 18 invasive cervical cancer proven histologically) were studied. A ring-design endovaginal coil of solenoid geometry was positioned around the cervix. Vaginal air, introduced during coil placement, was aspirated to reduce B0 inhomogenities. Studies were performed at 1.5T. Cervical tumour was delineated on T2-weighted images. 1H spectroscopic imaging was performed localised to the cervix using the PRESS technique (TR/TE 888/135ms, 4 signal averages, 17mins). Total Choline (tCho) peak was set as 3.2ppm and peak area measured using LCMODEL software. Tissue water from the same voxel was used as an internal standard. Spectral analysis was done on tumour voxels (>50% tumour), stromal voxels (>50% stroma, no tumour) and epithelium (>50% epithelium, no tumour). Independent two-sample t-tests adjusted for multiple comparisons were used to identify significant differences between individual groups.

Results

tCho/water ratio was significantly increased in tumour voxels (6.7±2.7) compared to epithelium voxels from CIN patients (4.6±1.8, p=0.021). A significant increase in tCho was observed in epithelial and stromal voxels adjacent to invasive cancer compared to voxels adjacent to CIN (p=0.012). tCho values in microinvasive disease were higher than in CIN but small patient numbers and high standard deviation meant results were not statistically significant.

Conclusion

tCho/ water ratio increases significantly between CIN and tumour voxels and shows potential as an indicator of the transition to invasive disease.