Fetal MRI Adds Clarity to the Ultrasound Image
Dec. 1, 1999 (Chicago) -- MRI (magnetic resonance imaging) is proving to be
a "complementary imaging technique" in cases where fetal ultrasound
results are inconclusive, according to two studies presented at the 85th
Scientific Assembly and Annual Meeting of the Radiological Society of North
Fergus V. Coakley, MBBCh, assistant clinical professor of radiology,
University of California, San Francisco, says that when questionable results
from ultrasound suggest a liver problem, his institution uses MRI. In one case,
a baby was delivered early after a problem was detected. He says the early
delivery allowed treatment, which averted the need for a liver transplant.
"Without the diagnosis by MRI, a transplant would have been
unavoidable," he says.
At Brigham and Women's Hospital in Boston, Mary C. Frates, MD, assistant
professor of radiology, Harvard Medical School, is using MRI to assess central
nervous system (CNS) and genital/urinary abnormalities. Frates says that MRI is
useful in "adding information that is not obtainable with just ultrasound,
even though ultrasound is a very useful tool." In her study she presented
results of 13 MRI evaluations done on 35 pregnant women who were referred for
MRI following ultrasound. Nine of the cases involved suspected CNS disorders,
and the MRI confirmed that diagnosis in all cases, she says. "In two of
these cases, the MRI provided additional information that assisted management
of the cases," she says. In the remaining four cases, the MRI confirmed
ultrasound diagnosis of genital/urinary abnormalities.
Frates says that sometimes the MRI can be useful in easing parental
concerns. In two of her cases, women had previously delivered babies with brain
damage. They wanted to have their current pregnancies checked out, but the
ultrasound examinations in both of these women were inconclusive. "With MRI
we were able to confirm that the fetuses were normal," Frates says.
In Coakley's study, 44 women were referred for MRI. The MRI confirmed
ultrasound findings in 36 cases and added additional information in 12 of those
cases. Moreover, the MRI clarified results in four cases in which the
ultrasound findings were inconclusive. In two cases, MRI added information that
was not available through ultrasound.
"MRI is especially useful in confirming diagnosis," says Frates.
"It is harder to see inside the brain as the fetus gets older if you are
using just ultrasound, but MRI overcomes this difficulty."
Frates adds that when ultrasound indicates a problem, "it is not unusual
to have an MRI scheduled for immediately after birth. But many of these fetuses
are quite ill when they are born and are on ventilators. It is difficult to
take an ICU [intensive care unit] baby and put him or her inside the MRI. But
when the fetus is inside the mother, it is in a stable environment, and we can
put the mother inside the magnet. It's a better option."