Retrospective review of 50 canine intracranial tumors evaluated by magnetic resonance imaging.

Magnetic resonance imaging (MRI) was performed on 50 dogs with intracranial neoplasia. The following tumor features were assessed: axial origin, location, shape, growth pattern, MRI signal intensity, evidence for edema, and paramagnetic contrast enhancement. Histologic diagnosis included 5 intracranially invading nasal tumors, 7 pituitary tumors, 22 meningiomas, 6 choroid plexus tumors, 7 astrocytomas, 1 ependymoma, and 2 oligodendrogliomas. Axial origin, site, shape, and growth pattern were important diagnostic characteristics for tumor type. Signal intensity and contrast enhancement pattern allowed further differentiation. Characteristic MRI features that facilitate diagnosis and prognosis were identified. Accurate diagnosis of tumor type based on these features was not always possible because of similarities in MRI appearance for some tumors. Tissue biopsy remains necessary for definitive diagnosis of intracranial tumors.

Diffuse cerebral and leptomeningeal astrocytoma in dogs: MR features.

Magnetic resonance (MR) imaging has increased sensitivity in detection of nonenhancing brain tumors and may show the extent of CNS neoplasia with greater detail than CT. Magnetic resonance images of the canine brain were acquired in two dogs with diffuse leptomeningeal and cerebral low grade astrocytoma. Abnormalities were identified with MR imaging when CT and CSF analysis were noncontributory. Changes seen with MR included decreased signal on T1-weighted images and increased signal on T2-weighted images consistent with vasogenic edema. Neither MR nor CT showed post-contrast enhancement. Magnetic resonance did not show the full extent of cellular infiltration, however. This was attributed to the diffuse submacroscopic distribution and absence of corresponding edema and contrast enhancement in certain regions of brain.

Vertebrobasilar injuries following cervical manipulation.

Four cases of brainstem stroke syndromes followed mechanical cervical manipulation; vascular injury was confirmed angiographically. A comprehensive review of the literature on vertebrobasilar injuries disclosed the various mechanisms of injury and pathogenesis of subsequent vascular complications following cervical manipulation. Emphasis is given to the potentially devastating neurological complications, particularly in view of the increasing utilization of chiropractic therapy.

Computed tomography of intracerebral leukemic masses.

Five patients with differing types of leukemia had clinical symptoms of a localized intracerebral leukemic mass. Computed tomography (CT) demonstrated a mass of equal or increased density relative to normal brain; a zone of surrounding edema was variable. In each case, the mass showed evidence of relatively uniform contrast enhancement. CT appearance of leukemic masses is consistent and quite different from the findings in other central nervous system complications of leukemia and its aggressive treatment.

Transient, severe periventricular hypodensity after leukemic prophylaxis with cranial irradiation and intrathecal methotrexate.

Serial computed tomography (CT) demonstrated complete resolution of severe periventricular hypodensity occurring in a child after receiving prophylaxis for acute lymphocytic leukemia. The resolution of this encephalopathy suggests that early changes of subacute necrotizing leukoencephalopathy are reversible and CT is copable of detecting these early changes.