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.

Acute unilateral enlargement of the parotid gland immediately post craniotomy in a pediatric patient: a case report.

A temporary acute unilateral enlargement of the parotid gland or "anesthesia mumps" has been described in both surgical and anesthesia literature. It has been described in elderly, dehydrated, poorly nourished, and post-operative patients. We present a 5-year-old patient who underwent a left temporal craniotomy for seizure focus resection and quadriceps muscle biopsy. Immediately post procedure, he was noted to have an acute unilateral enlargement of the right parotid gland. We report acute unilateral parotitis as a possible, but uncommon, complication of positioning in the pediatric population and to discuss possible pathophysiology and prevention, as well as a review of the available literature.

Treatment of intermittent obstructive hydrocephalus secondary to a choroid plexus cyst.

The authors present the case of an 11-week-old girl in whom hydrocephalus developed secondary to intermittent obstruction of the third ventricle by a choroid plexus cyst. The patient presented to the emergency department at the authors' institution with a 1-day history of projectile vomiting, lethargy, and dysconjugate gaze. Hydrocephalus was confirmed on head CT. During hospitalization, the symptoms resolved with a decrease in ventricular size. One week later, the patient again presented with similar symptoms, and MR images with 3D-constructive interference in steady state sequences revealed that a cyst was blocking the third ventricle. The patient subsequently underwent endoscopic fenestration of the cyst with resolution of hydrocephalus and symptoms. The authors present a unique description of the diagnosis of intermittent obstructive hydrocephalus caused by a third ventricular region choroid plexus cyst in an infant.