What MRI view is recommended for a patient with secondary infertility and a history of ectopic pregnancies to investigate the fallopian tubes and ovaries?

MRI Pelvis Without Contrast in Sagittal and Axial Planes

For secondary infertility with prior ectopic pregnancies, obtain MRI pelvis without IV contrast using sagittal and axial T1- and T2-weighted sequences to evaluate for hydrosalpinx, tubal scarring, and deep infiltrating endometriosis. 1, 2

Rationale for MRI in This Clinical Context

A history of ectopic pregnancy strongly suggests tubal damage, which accounts for 14% of female infertility cases and is most commonly caused by prior pelvic inflammatory disease (PID) leading to tubal scarring, occlusion, and peritubal adhesions. 2 MRI is superior to transvaginal ultrasound for detecting hydrosalpinx and chronic sequelae of PID, with 75.6% accuracy in diagnosing hydrosalpinx compared to surgical findings. 1

Specific MRI Protocol Requirements

Standard Sequences Without Contrast

• T2-weighted sequences in sagittal and axial planes are essential for detecting fluid-filled dilated fallopian tubes (hydrosalpinx), which appear as hyperintense tubular structures separate from the ovaries. 1
• T1-weighted sequences help identify hemorrhagic content within tubes (hematosalpinx from endometriosis) and detect endometriomas, which show high signal on T1 with low signal on T2 (T2 shading). 1, 2
• No routine IV contrast is required for evaluating tubal pathology or endometriosis, though contrast is useful for assessing acute PID or characterizing ovarian masses with enhancing components. 1

Why These Views Matter

• Sagittal planes optimally visualize the relationship between the uterus, posterior cul-de-sac, and rectovaginal septum—critical for detecting deep infiltrating endometriosis with 88% sensitivity and 83.3% specificity in posterior locations (uterosacral ligaments, retrocervical region). 1
• Axial planes best demonstrate bilateral tubal pathology, peritubal adhesions, and the relationship of tubes to adjacent pelvic structures. 3, 4

Key MRI Findings to Identify

Tubal Pathology

• Hydrosalpinx: Fluid-filled, dilated fallopian tubes appearing as C-shaped or S-shaped tubular structures with incomplete septations ("cogwheel sign") on T2-weighted images. 1, 4
• Peritubal adhesions: Suspected when tubes are fixed in abnormal positions, with obliteration of normal tissue planes and low-signal intensity bands. 1

Associated Endometriosis

• Endometriomas: High T1 signal with T2 shading (sensitivity 82-90%, specificity 91-98%). 1, 2
• Deep infiltrating endometriosis: Low signal intensity regions on T2 with or without hyperintense foci on T1, particularly in the posterior cul-de-sac, uterosacral ligaments, and rectovaginal septum (sensitivity 92.4%, specificity 94.6% for intestinal involvement). 1, 2
• Cul-de-sac obliteration: Adherence or angulation of bowel loops toward the posterior uterus (83.7% sensitive), displacement of pelvic free fluid (95% sensitive), or retrouterine fibrous mass (97.1% sensitive). 1

Critical Pitfalls to Avoid

• Do not assume normal transvaginal ultrasound excludes tubal pathology: Up to 21% of women with surgically confirmed endometriosis have normal hysterosalpingography, and ultrasound is only 86% sensitive for hydrosalpinx. 1, 2
• MRI cannot definitively assess tubal patency: While MRI detects hydrosalpinx and structural abnormalities, it cannot confirm whether tubes are patent. Hysterosalpingography or sonohysterography with tubal contrast agent (HyCoSy) is required for patency assessment if the patient is actively pursuing pregnancy. 1, 2
• Prior ectopic pregnancy increases risk of recurrent ectopic: MRI helps identify structural tubal damage that predisposes to repeat ectopic implantation, guiding decisions about assisted reproductive technology versus tubal surgery. 5, 4

Complementary Imaging Considerations

• Hysterosalpingography (HSG) should be performed if tubal patency assessment is needed, though it is only 65% sensitive and 85% specific compared to laparoscopy with chromopertubation. 1
• Transvaginal ultrasound remains the initial imaging modality for ovarian reserve assessment (antral follicle count, ovarian volume) and should precede MRI. 2, 6
• Dynamic MR-hysterosalpingography is an emerging technique using intracavitary gadolinium injection to directly visualize tubes and assess patency without ionizing radiation, though it is not yet widely available. 7, 8

When to Proceed to Laparoscopy

Laparoscopy with chromopertubation remains the gold standard for diagnosing tubal patency and staging endometriosis, reserved for cases where empirical therapy fails, MRI findings are indeterminate, or immediate histological confirmation is required. 2, 9 Only surgeons experienced with the protean appearances of endometriosis should rely on visual inspection; peritoneal biopsy should confirm questionable lesions. 2