Gadolinium-based contrast media should not be routinely used for pediatric MRI brain scans if unenhanced images are normal, say pediatric radiologists from University Hospital Leipzig in Germany, who analyzed more than 6,500 such MRI studies. Relevant findings were identified in only 0.3% of patients after gadolinium application, all of which presented as pathological meningeal enhancement, say the researchers who published their findings in the June issue of Pediatric Radiology. According to the study, the probability of missing a relevant pathological meningeal enhancement in the case of a normal unenhanced MRI is approximately 3 per 1,000,000 children.
For the study, two experienced pediatric radiologists reassessed all brain MRI scans of children younger than 17 years imaged between July 2005 and October 2016. They categorized the clinical indications for brain imaging into 12 groups, the majority of which were suspected or known brain tumors (30%), clinically proven neurological findings (25%), and seizures (21%). They determined whether abnormal findings were detected before contrast administration and whether there were any diagnostic benefits to additional post-contrast sequences.
In 3,003 examinations, no abnormalities were identified before contrast administration. No pathological findings were detected in 95% in scans with contrast. Only about 5% revealed irrelevant coincidental findings, primarily developmental venous anomalies. Only eight exams revealed a relevant additional finding, specifically pathological meningeal enhancement.
“The administration of contrast medium in examinations without pathological findings in unenhanced sequences has an estimated likelihood of 0.12-0.52% of adding any relevant information in cohorts similar to the one studied here,” wrote the authors. They recommend that gadolinium-based contrast medium should be administered only for further characterization of equivocal lesions detected in a
noncontrast scan or to exclude meningeal involvement when a tumor or infection has been diagnosed.
In their analysis of the eight exams identifying pathological meningeal enhancement, Ina Sorge, MD, and co-authors stated that four children had bacterial meningitis, one had viral meningitis from enterovirus, one had meningeal irritation from a fracture, one had had a lumbar puncture before the MRI, and one had suspected but unconfirmed meningitis.
Normal unenhanced pediatric MRI brain scans don’t require gadolinium-based contrast sequences. Appl Radiol.