The role of magnetic resonance imaging in oncogynecology
Magnetic resonance imaging (MRI) is essential at all stages of patient management—from initial assessment of local tumor extent to risk stratification and follow-up.
- Endometrial cancer: MRI provides precise surgical planning, specifically allowing assessment of the depth of myometrial invasion. Based on these data, physicians select high-progression-risk patients for pelvic or para-aortic lymphadenectomy. Simultaneously, this avoids unjustifiably extensive and traumatic surgical interventions in low-risk patients.
- Cervical cancer: The examination improves the accuracy of clinical staging according to the updated FIGO system and facilitates the selection of adequate treatment tactics. Furthermore, MRI is essential when planning fertility-sparing surgery in early-stage disease.
- Ovarian cancer: The modality plays a major role in assessing resectability in solitary pelvic recurrences.
In complex cases, such as persistent or recurrent malignancies, preoperative MRI is mandatory before performing pelvic exenteration.
Assessment of complex adnexal masses and carcinomas
For the differential diagnosis of complex adnexal masses, the standard MRI protocol is supplemented with perfusion-weighted and diffusion-weighted imaging (DWI) sequences.
A clear example is the visualization of clear cell carcinoma of the ovary:
- On axial T2-weighted images, the tumor appears as a predominantly cystic mass with irregular septations and mural nodules. This solid component demonstrates intermediate signal intensity.
- On diffusion-weighted images, the solid component shows a hyperintense signal.
- On apparent diffusion coefficient maps (ADC maps), a hypointense signal is determined in the corresponding areas.
Combined evaluation of DWI and ADC maps reliably confirms the presence of true diffusion restriction within soft tissue nodules. This imaging sign reflects high cellularity, which is pathognomonic for a malignant process.
Application of PET/CT in gynecological oncology
Positron emission tomography combined with computed tomography (PET/CT) using fluorodeoxyglucose (FDG) is increasingly used to evaluate gynecological malignancies.
Main indications for PET/CT:
- Initial staging of cervical cancer.
- Detection of recurrences of cervical, ovarian, and endometrial cancer.
In ovarian cancer recurrence, combined PET/CT images visualize areas of active radiopharmaceutical uptake. Typical radiological findings include metastases in bilateral pelvic lymph nodes, as well as the presence of peritoneal implants in the pelvic cavity. This method outperforms standalone CT in detecting metabolically active foci of tumor tissue.
Prediction of surgical treatment and therapy response
Imaging modalities are critical for predicting treatment outcomes:
- Optimal cytoreduction: CT and MRI are used to assess the feasibility of optimal cytoreductive surgery in patients with newly diagnosed primary epithelial ovarian cancer.
- Neoadjuvant chemotherapy: In advanced ovarian cancer, DWI-MRI is used to assess tumor response to treatment (by correlating ADC with histological data).
- Risk assessment: To standardize ultrasound and MRI reports, the «Simple Rules» developed by the IOTA group are actively used, allowing the calculation of the risk of malignancy in adnexal masses.
Briefly: answers to topical questions
Which anatomical structures and parameters are assessed on MRI for precise FIGO staging of cervical cancer?
For precise FIGO staging of cervical cancer on MRI, tumor location, tumor size, and involvement of adjacent structures are evaluated. The evaluated parameters and anatomical structures include:
- Cervix — tumor size, distance to the internal os, cervical length, and integrity of the stromal ring are determined.
- Parametrium (parametrium) — presence of invasion is identified (spiculated border, spread of the soft tissue component).
- Vagina — invasion into the upper 2/3 or lower third is assessed.
- Uterine vessels — evaluated for tumor encasement (encasement).
- Pelvic wall — tumor spread is assessed.
- Lymph nodes — metastases are identified.
- Kidneys — presence of hydronephrosis or a non-functioning kidney is determined.
What specific imaging features are included in the IOTA «Simple Rules» for assessing the risk of malignancy?
The IOTA «Simple Rules» (Simple Rules) for assessing malignancy risk include ultrasound descriptors divided into «B-rules» and «M-rules».
| Benign features | Malignant features |
|---|---|
| Unilocular cyst | Solid components |
| Solid component dimensions = 100 mm | |
| No blood flow on color Doppler | Very strong blood flow on color Doppler |
Which pelvic organs and structures are removed during exenteration for recurrent malignancies?
When performing pelvic exenteration for recurrent malignancies, the removed organs depend on the extent of surgical intervention. The following types of surgery are distinguished:
- Total exenteration — removal of the urinary bladder, uterus, vagina, and rectum.
- Anterior exenteration — removal of the urinary bladder, uterus, and vagina.
- Posterior exenteration — removal of the uterus, vagina, and rectum.
Class and exam questions
Why are DWI and ADC maps evaluated together in pelvic MRI?
Their joint analysis allows for the reliable detection of diffusion restriction in solid components and nodules. This indicates high tissue cellularity, which is a typical sign of a malignant neoplasm.
When is FDG PET/CT indicated for a patient with oncogynaecological pathology?
The main indications are initial staging of cervical cancer, as well as the search for and confirmation of recurrences of ovarian, endometrial, and cervical carcinoma (e.g., detecting affected lymph nodes and peritoneal implants).
How does MRI assist in endometrial cancer treatment planning?
MRI accurately assesses the depth of tumor invasion into the myometrium. This helps identify high-risk patients for lymphadenectomy and protects low-risk patients from unjustifiably extensive surgeries.
What else to study on this topic
- Features of MRI staging of uterine and cervical cancer according to ESUR clinical guidelines.
- Dynamic contrast-enhanced imaging combined with diffusion-weighted imaging in gynecological cancer.
- The revised FIGO staging system for vulvar, cervical, and endometrial carcinomas.
- Application of IOTA «Simple Rules» to predict the risk of malignancy in adnexal masses.
- Correlation of the apparent diffusion coefficient (ADC) with histological data in assessing response to neoadjuvant chemotherapy.
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