MRI superior to ultrasound for diagnosing fetal brain abnormalities

By Will Boggs MD

NEW YORK (Reuters Health) - MRI is more accurate than ultrasound for diagnosing fetal brain abnormalities in utero, according to results from the MERIDIAN study.

"Any pregnancy complicated by a fetal brain abnormality should be offered an in utero MRI (iuMRI)," Cara Mooney, MERIDIAN study manager from the University of Sheffield in the U.K., told Reuters Health by email.

Fetal imaging with ultrasonography is the mainstay of antenatal screening programs and detailed anomaly scanning in the U.K., but studies have suggested that iuMRI might be a useful adjunct for detecting fetal brain abnormalities.

Mooney and colleagues investigated the diagnostic performance, clinical impact, and acceptability of iuMRI to pregnant women for the prenatal diagnosis of fetal brain abnormalities.

The overall diagnostic accuracy of iuMRI was 93%, compared with 68% for ultrasound, according to the study, online December 14 in The Lancet.

Incorrect ultrasound reports were corrected by iuMRI in 25% of cases, whereas only two fetuses (

The dominant diagnosis was reported with high confidence on ultrasound in 82% of cases compared with 95% on iuMRI.

In 49% of cases, iuMRI provided additional diagnostic information and in at least 20% it changed prognostic information (improving the prognosis in 13% and worsening it in 12%).

At least 95% of women said they would have an iuMRI study if a future pregnancy were complicated by a fetal brain abnormality.

"These findings should influence our diagnosis of fetal brain abnormalities by introducing iuMRI into the diagnostic clinical pathway in any pregnancy where a fetal brain abnormality is suspected on ultrasound," Mooney concluded. "The improved accuracy and higher confidence of the information provided by iuMRI will better inform the counseling and management decisions of the pregnancy."

Dr. Rodney C. Scott from the University of Vermont College of Medicine in Burlington, who coauthored an accompanying commentary, told Reuters Health by email, "The primary result that iuMRI is a better tool for the diagnosis of fetal brain abnormalities than the current gold standard of ultrasound is a critically important result. This result is entirely unsurprising but nevertheless needed to be rigorously shown."

"iuMRI will allow fetal medicine practitioners to provide detailed and accurate information to parents, making shared decision making more reliable," he said. "The decisions that need to be taken are extremely difficult for parents, and those difficulties are enormously greater when the physician is not able to be definitive about the nature of the brain abnormality."

"However," Dr. Scott added, "the precise relationship between the abnormality and outcome in the baby still needs to be defined more clearly. Follow-up of babies included in studies like MERIDIAN will ultimately provide this information, further increasing the value of iuMRI."

Dr. Catherine Limperopoulos from Children's National Health System in Washington, D.C., who has published extensively on fetal brain development and its assessment, told Reuters Health by email, "The study clearly demonstrates the added diagnostic benefit of performing in utero MRI for fetuses with a possible brain abnormality on ultrasound that results in vital changes in counseling and management of the high-risk pregnancy."

"A diagnosis of a fetal brain anomaly is a major stressor for pregnant parents and effective counseling and informed decision making depend on accurate prenatal diagnosis," said Dr. Limperopoulos, who was not involved in the study. "Therefore, fetal MRI should become a standard imaging tool for fetuses with suspected brain abnormalities on ultrasound."

"The very high overall acceptability of in utero MRI by pregnant women suggests that MRI plays an important role in helping mothers understand their fetus' condition and future neurologic outcome," she added.

SOURCE: https://bit.ly/2igGUY8 and https://bit.ly/2hdUIRt

Lancet 2016.