Faculty Bibliography

Computed tomography (CT) and magnetic resonance (MR) imaging were performed in ten patients with paranasal sinus hemorrhage after trauma. Acute or subacute hemorrhage was detected on MR images by using T1- and T2-weighted imaging to identify the chemical state of the blood and to differentiate blood from mucosal thickening and sinus effusion. Surgical proof of intrasinus hemorrhage was obtained in only two cases. Displaced fractures, associated cerebral contusions, and traumatic encephalocele were well shown on MR imaging. Nondisplaced and minimally displaced fractures were better evaluated with CT

Magnetic resonance (MR) imaging was used to evaluate normal fetal intracranial anatomy in axial, coronal, and sagittal planes. The T1 and T2 weighted images (WI) of aborted fetuses of varying gestational ages were correlated with anatomic sections. In the premature fetus three distinct intensity zones were seen on MR that were not visualized on gross specimens. Unmyelinated white matter displays low intensity on T1 W1 and high intensity on T2 W1. Maturational changes of the brain were observed with advancing fetal age

Disseminated necrotizing leukoencephalopathy is a rare syndrome of progressive neurologic deterioration seen most often in patients who have received central nervous system irradiation combined with intrathecal or systemic chemotherapy in the treatment or prophylaxis of various malignancies. Magnetic resonance imaging was more sensitive than computed tomography in detecting white matter abnormalities in the case of disseminated necrotizing leukoencephalopathy reported here. Magnetic resonance imaging may be useful in diagnosing incipient white matter changes in disseminated necrotizing leukoencephalopathy, thus permitting early, appropriate therapeutic modifications

Appropriate spin-echo (SE) pulse sequence parameters generate magnetic resonance (MR) images with very high gray matter/white matter contrast in neonates and young infants. In these young patients, long SE sequences with a repetition time of 3,000-3,500 msec and multiple echoes with the longest echo time of 120-160 msec are employed to yield high-contrast images. A high-contrast MR image of a 1-month-old infant is presented

Two patients with surgically and angiographically proved partially thrombosed giant aneurysms of the middle cerebral artery were studied with computed tomography (CT) and magnetic resonance (MR) imaging. MR and histopathologic findings were correlated. The central location of methemoglobin, with its high intensity (surrounding the patent lumen, seen as signal void), in giant aneurysms is directly opposite the initial peripheral appearance of methemoglobin in extra-aneurysmal intracerebral hematomas. More peripherally, the thrombosed portion of the lumen is layered with intensities that represent stages of clot (methemoglobin and hemosiderin). Three characteristics enable differentiation of giant aneurysms from intracerebral hematoma: signal void in residual patent lumen; laminated, staged thrombus with intervening layers of hemosiderin and methemoglobin that is initially centrally, rather than only peripherally, located; and signal void in the vessel from which the aneurysm arises. Hemorrhage from prior bleeding can be readily identified and separated from perianeurysmal edema on MR images. MR appears to be a specific, noninvasive method for diagnosing partially thrombosed giant intracranial aneurysms and is superior to CT and angiography in characterizing these lesions

Gliomatosis cerebri is a rare condition characterized by diffuse overgrowth of large portions of the brain and spinal cord by glial cells in varying stages of differentiation. The tumor process is primarily an infiltrative, rather than a destructive one. Hence, pre-operative diagnosis by traditional imaging studies, including computed tomography (CT), has been difficult. Magnetic resonance imaging (MRI), with its unique sensitivity for cerebral pathology, is an ideal modality for demonstrating this lesion. We present three cases of gliomatosis cerebri in which high-field MRI clearly delineates the extent of the pathologic process

1.5 Tesla MRI examinations were evaluated for aqueductal configuration, hydrocephalus and flow-related signal void in 70 patients with juxtaaqueductal pathology and in 20 normal controls. In the 70 cases with pathology, the aqueduct was obliterated or distorted in 34, dilated in 3, normal in 29 and not evaluable in 4. A definite flow-related signal void indicated CSF movement within the aqueduct in all normal examinations. Flow-related signal void was absent in some, but not all, patients with aqueductal obliteration and distortion. CSF turbulence can create an intra-aqueductal signal void in the dilated proximal aqueduct, despite more distal obstruction. Thus hydrocephalus related to aqueductal obstruction is frequently, but not always, associated with absence of signal void

Two cases of superficial siderosis with subependymal siderosis, secondary to neonatal intraventricular hemorrhage, are presented. High-field spin-echo MR imaging (1.5 Tesla) showed marginal hypointensity of the ventricular walls as well as of the subpial regions. These findings were most evident on T2 weighted images, characteristic of hemosiderotic deposits

In seven patients with temporal bone fractures examined by both CT and MRI, thin section CT proved superior to MRI in demonstrating the full extent of the fractures and the status of the ossicular chain. MR studies were able to demonstrate fractures, when these fractures contained blood or CSF, and the presence of ossicular dislocation in one case where the middle ear was completely filled with CSF or blood. Admixture of air in the middle ear gave a false impression of ossicular dislocation, while air in the fracture obscured portions of it. MR proved superior to CT in the evaluation of intracranial contents by showing 5 additional subdural hematomas, 2 epidural hematomas and 2 hemorrhagic contusions

Eleven patients with sickle cell disease and neurological symptoms underwent MRI examination. Cerebral infarcts of two types were found, those in the vascular distribution of the middle cerebral artery and those in the deep white matter. In the patient whose hydration and whose oxygenation of erythrocytes has been treated, MRI offers diagnostic advantages over arteriography and CT