DTI fiber tracking to differentiate demyelinating diseases from diffuse brain stem glioma.

OBJECT: Intrinsic diffuse brainstem tumors and demyelinating diseases primarily affecting the brainstem can share common clinical and radiological features, sometimes making the diagnosis difficult especially at the time of first clinical presentation. To explore the potential usefulness of new MRI sequences in particular diffusion tensor imaging fiber tracking in differentiating these two pathological entities, we review a series of brainstem tumors and demyelinating diseases treated at our institution. MATERIAL AND METHODS: The clinical history including signs and symptoms and MRI findings of three consecutive demyelinating diseases involving the brainstem that presented with diagnostic uncertainty and three diffuse intrinsic brainstem tumors were reviewed, along with a child with a supratentorial tumor for comparison. Fiber tracking of the pyramidal tracts was performed for each patient using a DTI study at the time of presentation. Additionally Fractional Anisotropy values were calculated for each patient in the pons and the medulla oblongata. RESULTS: Routine MR imaging was unhelpful in differentiating between intrinsic tumor and demyelination. In contrast, retrospective DTI fiber tracking clearly differentiated the pathology showing deflection of the pyramidal tracts posteriorly and laterally in the case of intrinsic brainstem tumors and, in the case of demyelinating disease, poorly represented and truncated fibers. Regionalized FA values were variable and of themselves were not predictive either pathology. CONCLUSION: DTI fiber tracking of the pyramid tracts in patients with suspected intrinsic brainstem tumor or demyelinating disease presents two clearly different patterns that may help in differentiating between these two pathologies when conventional MRI and clinical data are inconclusive.

Evaluation and management of children with holoprosencephaly.

Recent advances in genetics and neuroimaging have greatly contributed to our understanding of the spectrum of midline brain and craniofacial malformations known as holoprosencephaly. Neuroradiologic studies have provided detailed characteristics of four major types of holoprosencephaly: alobar, semilobar, lobar, and middle interhemispheric variant. Clinical studies in children with these types of holoprosencephaly have revealed a wide range of survival and neurologic outcomes. Motor and developmental dysfunctions correlate with the severity of the brain malformation in holoprosencephaly. These findings have implications in the management of medical problems associated with holoprosencephaly and overall prognostication.