Pelvic MRI Protocol, Anatomy, and Reporting Approach

Pelvic MRI is not one fixed examination. Questions about the uterus, adnexal mass, rectum, prostate, bladder, or pelvic floor require different planes, sequences, and contrast decisions. A useful report defines the clinical question and target organ, then organizes findings by organ and pelvic compartment.

High-resolution T2 images are planned perpendicular and parallel to the target organ. T1 images assess fat, blood, and marrow. Diffusion provides supporting information about cellularity, and contrast-enhanced imaging can assess solid tissue and tumor spread. Diffusion signal alone does not establish malignancy.

Assessment framework

• Confirm the indication and target organ before planning the protocol.
• Add small-field-of-view organ-specific T2 images to wide-field axial coverage.
• When blood or fat is possible, compare fat-suppressed and non-fat-suppressed T1 images.
• Establish organ origin and intraperitoneal or extraperitoneal location.
• Review ureters, bladder, rectum, pelvic sidewalls, vessels, and lymph nodes systematically.

What the report should contain

• Measure a lesion in three planes on the same sequence.
• Describe T1, T2, diffusion, and enhancement in separate statements.
• Distinguish contact with an adjacent organ from invasion.
• Assess nodal morphology and distribution as well as short-axis diameter.
• Put a technical limitation in the impression when it affects the target question.

Common errors

• Using the same protocol for every pelvic indication.
• Calling loss of a low-T2 band invasion by itself.
• Listing a long differential before establishing organ origin.

Example report wording

Example technique note: Wide-field T1, T2, and diffusion images of the pelvis were supplemented with high-resolution T2 series perpendicular and parallel to the uterus. Postcontrast fat-suppressed T1 imaging was obtained. Mild motion artifact does not materially limit myometrial assessment.

When origin is uncertain, use the MRI checklist for uterine origin of a pelvic mass.

References

1. American College of Radiology. Practice Parameter for MRI of the Soft-Tissue Components of the Pelvis. Source (opens in a new tab)
2. American College of Radiology. Practice Parameter for CT of the Abdomen and Pelvis. Source (opens in a new tab)

Clinical note: This material is for radiology education. Do not generate an automatic diagnosis or management decision without checking guideline scope, patient factors, and local policy.