Imaging of the pituitary gland an important tool in pediatric endocrinology
Canadian Pediatric Endocrine Group
TORONTO — Magnetic resonance imaging of the pituitary gland is an important clinical tool for predicting future risk for multiple pituitary hormone deficiencies, researchers said here.
Patients with the classic triad — interrupted or thin pituitary stalk, absent or ectopic posterior pituitary and anterior pituitary hyperplasia — are at greater risk for developing multiple pituitary hormone deficiencies.
Sarah Tsai, MD, FRCPC, a pediatric endocrinology fellow at Children’s Hospital of Eastern Ontario in Ottawa, Canada, and colleagues conducted a review to examine the relationship between the degree of hormonal dysfunction and pituitary anatomy.
The review focused on MRI findings of 52 pediatric patients who were diagnosed with growth hormone deficiency and had received GH treatment from 1988 to 2010. Thirty-seven patients were determined to have isolated GH deficiency; of these, four had the classic triad, eight had varying degrees of pituitary anatomy abnormalities and 25 had normal MRI findings. Fifteen of the 52 patients were found to have mutiple pituitary hormone deficiencies; of these, nine had the classic triad, five had variants of the triad and one had a normal MRI.
“Of note, there were some mild abnormalities in the ‘normal’ group,” Tsai said.
There were differences in the reading of MRI images from the initial report in nine of the 52 cases, including four cases of inappropriate identification of a pituitary microadenoma and five instances of misidentification of one or more elements of the classic triad.
“It is a good idea to review with a pediatric neuroradiologist if you have an unexpected result,” Tsai said in an interview with Endocrine Today. “That may be someone who has multiple pituitary hormone deficiencies like GH, thyroid-stimulating hormone and adrenocorticotropin-releasing hormone and they have a normal MRI.”
Tsai noted that patients who have many pituitary hormone deficiencies tend to have more abnormal pituitary glands on MRI.
“If you have found someone with many deficiencies and a normal MRI, that would be unusual,” she said.
According to the researchers, the number of patients who had abnormal pituitary anatomy in this study is consistent with current literature.
A limitation of the study was that the pediatric neuroradiologist was not blinded to the results of the initial MRI finding nor the hormone status of the patient. – by Louise Gagnon
For more information:
- Tsai SL. Oral Abstract 9. Presented at: the Canadian Pediatric Endocrine Group 2011 Scientific Meeting; Feb. 10-12, 2011; Toronto.
Disclosure: Dr. Tsai’s research has been supported by a Canadian Pediatric Endocrinology Group scholarship that was funded by Sandoz.
It is very important when doing the reviews of MRI imaging, in the case of congenital hypopituitarism, that people realize when looking at hormone deficits it is an evolving phenotype. It is important to track these children even if you find that they may have only an isolated GH at the time of diagnosis. When you find some of these MRI anomalies on the midline, you should track these children very carefully because they can ultimately develop multiple hormone deficiencies. The other side of the coin, in patients for whom you have an absolutely normal MRI and a GH insufficiency, these patients all need to be retested. The question of whether this is true GH insufficiency needs to be asked before proposing that GH therapy be continued in adulthood.
– Cheri Deal, MD, PhD
Professor of Medicine, University of Montreal
President, Canadian Society of Endocrinology and Metabolism
Disclosure: Dr. Deal has been a speaker for Pfizer, Eli Lilly, EMD Serono and Novo Nordisk.
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