Incidental Findings and Their Significance in Rectal MRI: UK Experience

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Rectal MRI is crucial for staging rectal cancer and guiding treatment.
• Incidental findings (IFs) can occur during these scans, necessitating evaluation.
• St George's Hospital utilizes a rectal MRI protocol lacking diffusion-weighted imaging (DW-MRI).

Purpose of the Study:

• To assess the frequency and clinical significance of IFs in rectal MRI performed without DW-MRI.
• To evaluate the impact of omitting DW-MRI on IF detection in rectal cancer staging.

Main Methods:

• Retrospective analysis of 134 rectal MRI reports.
• Stratification of IFs based on clinical significance.
• Review of medical records for clarification of significant IFs.

Main Results:

• 38% (51/134) of rectal MRI studies identified incidental findings.
• Significant IFs were found in 15% (7/46) of baseline cancer staging studies.
• Common IFs included diverticular disease; one bladder malignancy was detected.

Conclusions:

• Clinically significant IFs are present in 12% of patients undergoing rectal MRI without DW-MRI.
• The overall rate of IFs (38%) is comparable to studies using DW-MRI, though fewer overall IFs were noted.
• Findings suggest that rectal MRI protocols omitting DW-MRI can still detect significant incidental findings, informing protocol development.