MRI plays a central role in assessing uterine cancers, including cervical cancer, endometrial cancer and suspected uterine sarcoma. Recommendations from the European Society of Urogenital Radiology, published in European Radiology, describe how MRI should be used for staging, treatment planning and selected fertility-sparing decisions. The recommendations also cover patient preparation, imaging protocols and structured reporting. Each uterine tumour type has different imaging features and treatment implications. Accurate assessment depends on clear protocols, careful evaluation of local tumour spread and consistent reporting of findings that may influence clinical management.
MRI as the Main Imaging Tool
MRI is the preferred imaging method for uterine malignancies because it provides strong soft tissue detail and images in several planes. Dedicated protocols include high-resolution T2-weighted imaging, diffusion-weighted imaging and contrast-enhanced sequences when needed. The protocol is adapted to the clinical question, including cervical cancer staging, endometrial cancer staging and assessment of an indeterminate myometrial mass.
Common reasons for MRI include staging cervical and endometrial cancers, checking whether fertility-sparing treatment may be possible and characterising myometrial lesions that remain unclear after earlier assessment. MRI may also help assess suspected local recurrence or clarify whether a tumour starts from the endometrium or the cervix when pathology is inconclusive.
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Patient preparation includes avoiding menstrual scheduling, fasting, a moderately filled bladder, antiperistaltic agents, supine positioning and optional vaginal gel. Reports should cover tumour site, size, depth and direction of spread, lymph-node status and additional findings relevant to treatment choice.
FDG-PET can complement MRI in cervical cancer because it performs well for lymph-node and distant metastases. CT is mainly used for systemic evaluation, distant staging or follow-up after treatment. The choice of imaging depends on tumour type, disease extent and the specific clinical question.
Assessing Cervical and Endometrial Cancer
In cervical cancer, MRI is used to define local tumour extent and guide treatment selection. It is mandatory when confirming eligibility for fertility-sparing surgery. Important features include maximum tumour size, distance from the tumour to the internal os and parametrial invasion. Cervical cancer usually shows intermediate signal on T2-weighted images, high signal on diffusion-weighted imaging and low apparent diffusion coefficient values.
Parametrial invasion is particularly important because it changes treatment from surgery to chemoradiation. Preservation of the low-signal cervical stromal ring on T2-weighted imaging helps exclude parametrial invasion. Full-thickness cervical stromal invasion alone does not mean that the tumour has spread into the parametrium. Parametrial invasion is diagnosed when full-thickness invasion appears with spiculated or nodular tumour extension into the parametrium, with or without vessel encasement.
In endometrial cancer, MRI is used to assess myometrial invasion and cervical stromal involvement. It is mandatory before fertility-sparing treatment to confirm that disease is confined to the endometrium. Endometrial cancer may appear as a mass, a polypoid lesion or diffuse endometrial thickening. It usually shows intermediate, often mixed signal and diffusion restriction. Histopathological evaluation remains the diagnostic gold standard.
MRI also supports assessment of extrauterine spread. Reports should document serosal, adnexal, vaginal, parametrial, bladder, rectal, lymph-node and peritoneal involvement where present. These findings are important because they affect staging and treatment decisions.
Distinguishing Myometrial Lesions
MRI is the imaging method of choice for indeterminate myometrial lesions, including cases where leiomyoma and leiomyosarcoma must be distinguished. Leiomyomas are common, while leiomyosarcomas are rare and are mostly diagnosed after menopause. The distinction matters because symptomatic leiomyomas may be treated conservatively or surgically, while leiomyosarcomas require prompt radical surgery.
Typical leiomyomas appear as round lesions with smooth or lobulated borders, low signal on T2-weighted and diffusion-weighted imaging and strong enhancement. However, degeneration and histological variants can make leiomyomas look atypical. These appearances can make reliable distinction from leiomyosarcoma difficult.
Features that raise suspicion for malignancy include irregular margins, intermediate-to-high signal on T2-weighted imaging, haemorrhage on T1-weighted imaging, central necrosis, high signal on high-b-value diffusion-weighted imaging and low apparent diffusion coefficient values. Menopausal status may also help improve diagnostic accuracy when used alongside imaging features, although further studies are needed.
Reports for myometrial lesions should include the lesion map, number, size and location. They should also state whether imaging features suggest benign or malignant disease. Peritoneal and lymph-node metastases should be assessed when leiomyosarcoma is suspected. Accurate preoperative identification of suspicious masses helps avoid inadvertent morcellation of an unsuspected malignancy while still supporting appropriate risk assessment in women with benign leiomyomas.
MRI protocols for uterine cancers support staging, treatment selection, fertility-sparing assessment and evaluation of recurrence. Cervical cancer assessment focuses on tumour size, internal os distance, parametrial invasion, vaginal involvement, lymph nodes and distant spread. Endometrial cancer assessment focuses on myometrial invasion, cervical stromal involvement, extrauterine extension, lymph nodes and peritoneal disease. Myometrial lesions require careful assessment for features suspicious for leiomyosarcoma. Consistent imaging protocols and structured reporting help provide clinicians with the information needed for treatment planning.
Source: European Radiology
Image Credit: iStock
References:
Ninkova RV, Bottazzi S, Lakhman Y et al. (2026) ESR Essentials: uterine cancers—practice recommendations by the European Society of Urogenital Radiology. Eur Radiol. https://doi.org/10.1007/s00330-026-12705-2
