High-resolution T₂-weighted cervical cancer imaging: a feasibility study on ultra-high-field 7.0-T MRI with an endorectal monopole antenna

Objectives: We studied the feasibility of high-resolution T₂-weighted cervical cancer imaging on an ultra-high-field 7.0-T magnetic resonance imaging (MRI) system using an endorectal antenna of 4.7-mm thickness. Methods: A feasibility study on 20 stage IB1–IIB cervical cancer patients was conducted. All underwent pre-treatment 1.5-T MRI. At 7.0-T MRI, an external transmit/receive array with seven dipole antennae and a single endorectal monopole receive antenna were used. Discomfort levels were assessed. Following individualised phase-based B₁ ⁺ shimming, T₂-weighted turbo spin echo sequences were completed. Results: Patients had stage IB1 (n = 9), IB2 (n = 4), IIA1 (n = 1) or IIB (n = 6) cervical cancer. Discomfort (ten-point scale) was minimal at placement and removal of the endorectal antenna with a median score of 1 (range, 0–5) and 0 (range, 0–2) respectively. Its use did not result in adverse events or pre-term session discontinuation. To demonstrate feasibility, T₂-weighted acquisitions from 7.0-T MRI are presented in comparison to 1.5-T MRI. Artefacts on 7.0-T MRI were due to motion, locally destructive B₁ interference, excessive B₁ under the external antennae and SENSE reconstruction. Conclusions: High-resolution T₂-weighted 7.0-T MRI of stage IB1–IIB cervical cancer is feasible. The addition of an endorectal antenna is well tolerated by patients. Key Points: • High resolution T₂-weighted 7.0-T MRI of the inner female pelvis is challenging• We demonstrate a feasible approach for T₂-weighted 7.0-T MRI of cervical cancer• An endorectal monopole receive antenna is well tolerated by participants• The endorectal antenna did not lead to adverse events or session discontinuation