MRI Volumetrics for Risk Stratification of Vision Loss in Optic Pathway Gliomas Secondary to NF1
Abstract
Nearly 20% of children with Neurofibromatosis type 1 (NF1) will develop a tumor of the visual system. The tumor, called an optic pathway glioma (OPG), causes irreversible vision loss leading to permanent disability in about 50% of children who have NF1, typically between 1 to 6 years of age. For unknown reasons, the other 50% of children with NF1-OPGs will not lose vision. Unfortunately, doctors do not have a good way of identifying which children will lose vision and when the vision loss will occur. Given this uncertainty, some children will sustain lifelong disability from their vision loss, even despite receiving treatment for their tumor, likely because treatment is started only after the loss of vision occurs. Also, for these exact same reasons, doctors may unknowingly treat NF1-OPGs that would have never caused vision loss. To address these clinical challenges, we will develop a novel quantitative magnetic resonance imaging (MRI) application that will accurately identify which children with NF1-OPGs will lose vision, thereby providing an opportunity to provide early treatment and preserve their vision. MRI is the standard imaging exam used to evaluate and monitor patients with NF1-OPG. Our application will inform doctors about which children can avoid unnecessary sedated MRIs and aggressive treatment with systemic chemotherapy—both of which have untoward side effects and risks of long-term toxicity in young developing children. Doctors consider two factors when deciding whether or not to start treating a child with a NF1-OPG. The first is the result of the ophthalmologic examination, specifically the visual acuity (i.e., the clarity of vision). The second is the results of the MRI. If the visual acuity is getting worse (e.g., difficulty reading the eye chart), then treatment is started. When the visual acuity remains unchanged, the doctor is reassured and treatment can be deferred. Unfortunately, most NF1-OPGs cause vision loss in younger children (i.e., < 3 years old) who cannot reliably complete the visual acuity testing due to their poor cooperation or problems common to NF1 (i.e., autism, developmental delay, attention deficit disorder). Thus, in children who cannot cooperate with the visual acuity testing, the doctor must base their treatment decision solely on the interpretation of the MRI. Using the MRI results to make treatment decisions for NF1-OPGs is also problematic. While MRI scans are very “high tech” images, the radiologist determines whether these irregularly shaped tumors get bigger or smaller in a very simple way: using a ruler to make 1-dimension (i.e., how wide is the tumor) or 2-dimension (i.e., how wide and tall) measures of the tumor. These simple and often inaccurate measures fail to extract a lot of important information from these “high tech” MRI scans. As such, the radiologist’s interpretation of MRI is not helpful in determining which child will lose vision from their NF1-OPG. Even when the tumor is being treated with chemotherapy, these basic measurements are not helpful in identifying whether the treatment is successful. To enable the full potential of MRI for NF1-OPGs, we will develop our novel quantitative MRI application to perform comprehensive measurements of these tumors’ volume, shape and texture. In turn, we will use these measurements to identify which children need treatment and which children undergoing therapy are responding favorably to their treatment. MRIs produce many types of distinctive images, called sequences. Each sequence is designed to highlight different features of brain tissue, such as inflammation, blood vessels, and texture. Our quantitative MRI application does not simply measure one type of MRI sequence, but instead performs a cumulative measure of all MRI sequence types. This type of comprehensive and objective measure cannot be reliably performed by humans, but instead relies on computer algorithms to process millions of data p
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 16, 2019
- Source ID
- W81XWH1910376
Entities
People
- Robert Avery
Organizations
- United States Army