Magnetic resonance imaging, coupled with the use of
the contrast dye gadolinium, may help pediatricians better
diagnose children with ulcerative colitis and Crohn's
disease, according to a study by researchers at the
Johns Hopkins
Children's Center.
Results of the study, published in the March issue of
Inflammatory Bowel Diseases, showed that the
gadolinium-enhanced MRII, or G-MRI, confirmed these
diagnoses in more than 90 percent of the children in the
study who had inflammatory bowel disease. Because
ulcerative colitis and Crohn's disease — two painful
ailments with similar origins and symptoms — have two
very different treatment regimens, especially if surgical
treatment is contemplated, early diagnosis is critical, the
researchers say.
"For the most severe cases of ulcerative colitis,
surgical removal of the colon is the only cure, while there
is no cure for Crohn's disease," says Anil Darbari, a
pediatric gastroenterologist at the
Children's Center and the lead author of the study.
"Unfortunately, many children who are originally diagnosed
with ulcerative colitis and have their diseased colon
surgically removed are later found to actually have had
Crohn's, which is discovered when the disease resurfaces in
another area within the intestinal tract.
"We also found that G-MRI was very helpful in
diagnosing pediatric small bowel disease, or IBD, which
occurs in an area in a child's body that is not accessible
by conventional endoscopies or colonoscopies," Darbari
said. "Because children with small bowel disease may not
exhibit traditional Crohn's disease symptoms, finding
definitive evidence of small bowel disease, which is
affiliated with Crohn's disease, prevents these children
from being labeled with indeterminate IBD and allows them
to begin the appropriate drug treatment right away."
Previous studies have shown G-MRI is effective in
distinguishing Crohn's disease and ulcerative colitis in
adults. However, this is believed to be the first study to
establish G-MRI as a radiological tool in diagnosing IBD in
children.
In the study, pediatric radiologists at the Johns
Hopkins Children's Center performed a G-MRI on 58 children
with suspected IBD between 1999 and 2002. Researchers used
intravenous gadolinium — a safe, commonly used
contrast dye — and other standard imaging tools to
enhance the image of the intestinal wall.
Based on G-MRI results, 30 children were classified as
having Crohn's disease, eight with ulcerative colitis, six
with possible Crohn's disease and 14 as having neither
disease. Researchers compared these findings with those
from more traditional IBD diagnostic tests, including
colonoscopy, in which a tiny scope is inserted through the
rectum to examine the lower digestive tract; computerized
tomography, which creates a 3-D image of the intestines;
small bowel image studies; and biopsied colon tissue. They
discovered G-MRI confirmed the diagnosis of ulcerative
colitis in 92 percent of patients and the diagnosis of
Crohn's disease in 96 percent of patients.
G-MRI is unlikely to replace colonoscopy, Darbari
said, because colonoscopy allows tissue samples to be
obtained and biopsied for further evaluation. However, he
added, for children with suspected small bowel disease,
G-MRI does provide a more sensitive, noninvasive diagnostic
tool and could replace conventional computerized tomography
and small bowel contrast studies.
Crohn's disease and ulcerative colitis primarily
affect the intestines, resulting in pain, severe diarrhea,
intestinal bleeding, weight loss and fever. Symptoms vary
in severity and duration; some patients suffer from
frequent prolonged attacks, and others have fewer
recurrences. Both diseases usually start in adolescence or
young adulthood but can also be seen in younger children.
In ulcerative colitis, the inner lining of the colon is
inflamed. People with Crohn's disease have similar
inflammation, but it extends deeper into the intestinal
wall and also can involve the small and large
intestines.
The study was supported in part by the Crohn's and
Colitis Foundation of America First Award and the Thomas
Wilson Sanitarium Awards. Co-authors of the study were
Laureen Sena and Carmen Cuffari, both of the Johns Hopkins
Children's Center; and Richard Thompson, of the Johns
Hopkins School of Public Health.
— Jessica Collins
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