Can a pelvic MRI help identify the cause of menorrhagia (heavy menstrual bleeding)?

Role of Pelvic MRI in Identifying Causes of Menorrhagia

Pelvic MRI is highly valuable as a second-line imaging modality for identifying causes of menorrhagia when ultrasound findings are inconclusive or further characterization is needed. 1

Initial Diagnostic Approach

1. First-line imaging: Transvaginal ultrasound (TVUS)

   • Combined with transabdominal ultrasound when appropriate
   • TVUS has 90-99% sensitivity for detecting uterine fibroids 1
   • TVUS with Doppler is the most useful initial evaluation for abnormal uterine bleeding 1

2. When to consider MRI:

   • When ultrasound is inconclusive or limited by:
     • Patient body habitus
     • Uterine position (e.g., retroverted)
     • Presence of multiple fibroids
     • Limited visualization of endometrium
     • Need for better characterization of findings

Advantages of MRI for Menorrhagia Evaluation

• Superior tissue characterization:

  • Excellent multiplanar capability and soft-tissue contrast resolution 1
  • Can visualize endometrium even when obscured by fibroids or adenomyosis on ultrasound 1
  • Differentiates between various causes of abnormal uterine bleeding

• Specific structural causes identifiable by MRI:

  1. Fibroids (leiomyomas)

     • Accurately identifies size, number, and location 1
     • Assesses vascularity and characterizes degeneration types 1
     • Helps distinguish between fibroids and adenomyosis 1

  2. Adenomyosis

     • 78% sensitivity and 93% specificity for diagnosis 1
     • Superior to ultrasound when coexisting with fibroids 1

  3. Endometrial abnormalities

     • Can identify endometrial hyperplasia, polyps, and cancer
     • Helps evaluate endometrial-myometrial interface 1

  4. Malignancies

     • Up to 79% sensitivity and 89% specificity for endometrial cancer 1
     • Diffusion-weighted imaging improves diagnostic accuracy 1

Optimal MRI Protocol for Menorrhagia

• Key sequences:

  • T2-weighted imaging for anatomical detail
  • T1-weighted imaging for hemorrhage detection
  • Diffusion-weighted imaging - important addition that improves sensitivity and specificity 1
  • Gadolinium-based IV contrast (preferred but not always necessary) 1

• Contrast considerations:

  • Helps assess fibroid vascularity 1
  • Aids in differentiating benign from malignant pathologies 1
  • May not be necessary in all cases 1

Clinical Algorithm for Menorrhagia Imaging

1. Start with TVUS ± sonohysterography

   • If findings are conclusive → proceed with appropriate treatment
   • If findings are inconclusive or limited → proceed to MRI

2. Pelvic MRI

   • Without and with contrast when malignancy is suspected
   • Without contrast may be sufficient for evaluating fibroids and adenomyosis

3. Treatment planning based on imaging findings

   • Medical management for diffuse pathologies
   • Targeted interventions for focal lesions
   • Surgical planning when indicated

Common Pitfalls to Avoid

• Relying solely on ultrasound when findings are inconclusive or limited
• Failing to use diffusion-weighted imaging in MRI protocols, which significantly improves diagnostic accuracy
• Not considering adenomyosis as a cause of menorrhagia when fibroids are present
• Overlooking the need for endometrial sampling in appropriate cases, regardless of imaging findings

MRI should not be used as a first-line imaging modality for all patients with menorrhagia but reserved for cases where ultrasound is inconclusive or additional information is needed for treatment planning.