Diffusion Tensor Imaging determines three-dimensional architecture of human cervix: a cross sectional study

Objective

To determine the microarchitecture of the cervix using high-resolution diffusion tensor (DT) magnetic resonance imaging (MRI).

Design

Cross-sectional study.

Setting

Leeds, UK.

Sample

Women undergoing hysterectomy for benign pathology.

Methods

Ex-vivo DT-MRI measurements were obtained using a 9.4-T Bruker nuclear magnetic resonance (NMR) spectrometer on seven fixed human cervices obtained at hysterectomy. A deterministic fibre-tracking algorithm was used to indirectly visualise underlying fibre organisation. Inter-regional differences in tissue structure were sought using quantitative measurements of diffusion.

Main outcome measure

The identification of an occlusive structure in the region corresponding to the internal cervical os.

Results

Fibre tracking demonstrated two regions: an outer circular and inner longitudinal layer. The total circumferential tract volume (TV) was greatest in the proximal region of the cervix (TV: proximal, 271 ± 198 mm3; middle, 186 ± 119 mm3; distal, 38 ± 36 mm3). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) measurements were significantly different between regions in all samples (P < 0.0005), indicating greater tract density and organisation towards the internal os.

Conclusion

Fibre tracking infers a system of dense, well-defined, encircling fibres in the proximal region of the cervix, corresponding to the location of the internal os. These findings may provide evidence of specific anatomic microarchitecture within the cervix able to resist intrauterine forces associated with pregnancy.