When can MRI make the difference for you in diagnosing a gyn abnormality?
MRI shouldn’t be the first-line modality for characterizing a mass. Rather, make it your effective problem-solver when ultrasonography has left the diagnosis in doubt.
IN THIS ARTICLE
Problem solving in pregnancy
To begin, note that, although MRI at 1.5 Tesla* is safe for use in pregnancy, studies on pregnant women should be performed only on patients in whom the diagnostic benefit is considered to outweigh the theoretical risk of the scan.
Malignancy is found in 2% to 5% of adnexal masses that are removed during pregnancy. Knowledge of the type of lesion is important to judge whether surgery can wait until after delivery or, if a malignancy is a concern, whether it is safest for the patient to have surgery during her pregnancy.
*Tesla is the unit of measurement of the strength of the magnetic field in an MRI scanner that determines the degree and quality of the visualization of anatomic detail.
Presentation: Pain. MRI is very helpful in pregnancy for assessing a patient who has right-lower-quadrant pain when US already has been utilized and the cause of the pain is unclear. MRI can be used in pregnancy to diagnose:
- appendicitis
- Crohn’s disease
- unusual cases of ectopic pregnancy
- ovarian torsion
- ureteral obstruction.
Placenta accreta. Typically, US is utilized to diagnosis placenta accreta. Sonographic findings of accreta include:
- loss of the hypoechoic retroplacental myometrial zone
- thinning or disruption of the hyperechoic uterine serosa or bladder interface
- focal exophytic masses
- lacunar flow.
Typically, a combination of transabdominal and transvaginal US scanning, with assessment of flow using color or power Doppler, or both, is sufficient in the postcesarean-delivery patient who has an anterior placenta previa. In a case in which a patient has had a myomectomy and has scars in the uterus in various locations, MRI can be helpful
In a case of suspected uterine dehiscence, MRI can be used to assess the entire uterine contour—a study that can be difficult with US.
Common indications for using MRI as a problem-solving tool in gynecology
| Distinguishing fibroids from adenomyosis |
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| Assessing an indeterminate adnexal mass |
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| Evaluation of pregnancy |
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Summing up
MRI is an exceptionally helpful modality in cases of gynecologic abnormalities that have not been, and cannot be, fully characterized by US. Keep in mind, however, that MRI should be used for problem solving—not for initial imaging!
Although the expense of pelvic MRI is much greater than the expense of US, MRI can provide a precise diagnosis—allowing you to establish the appropriate treatment plan. If that plan alters the need for, or invasiveness of, surgical management, then you have improved the quality of your care; possibly made follow-up imaging unnecessary; and, perhaps, reduced the cost of care over the longer term.
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