Stephen Kralik

While experienced pediatric neuroradiologists can differentiate low-grade brain tumors from high-grade brain tumors in most patients, information obtained from MR perfusion techniques can improve accuracy in some patients whose imaging features are otherwise indeterminate. Pediatric primary brain tumors have diverse cellular origins that result in diverse imaging appearances and, consequently, challenges in the diagnosis based on anatomic MRI appearance.

While much of the literature has focused on relative cerebral blood volume measurements from DSC MR perfusion, additional information can be obtained by reviewing the perfusion pattern. We chose to investigate the DSC perfusion patterns of pediatric brain tumors because there was a limited description in the literature for pediatric brain tumors, while the adult literature had suggested the value of these patterns in differentiating some adult brain tumors.

In this study, we evaluated 63 pediatric patients who had untreated primary brain tumors with DSC MR perfusion and characterized the tumor contrast leakage patterns. The striking finding in our data was the 100% positive predictive value for low-grade tumors if a T1-dominant leakage pattern (a pattern characterized by a postbolus signal intensity above baseline) was identified. This pattern was predominantly found in pilocytic astrocytomas and pilomyxoid astrocytomas, suggesting a correlation with tumor histology and vascular permeability.

We believe that the addition of MR perfusion techniques to preoperative imaging of pediatric patients with brain tumors may help radiologists reach an accurate diagnosis and provide data that cannot otherwise be known from conventional MRI sequences. We plan on continuing to investigate various perfusion techniques in pediatric patients with primary brain tumors to continue to advance the imaging capabilities for these patients.

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