Recurrent intracranial stenosis induced by the Wingspan stent: comparison with balloon angioplasty alone in a single patient.

We present a case in which angioplasty alone and stent-assisted angioplasty were performed in the same patient to treat medically refractory intracranial stenoses. This elderly patient with presumed intracranial atherosclerotic disease underwent angioplasty alone for his anterior cerebral artery stenosis. Stent-assisted angioplasty was used for treatment of his ipsilateral middle cerebral artery stenosis. Follow-up angiography at 4 months documented severe recurrent stenosis confined only to the stented portion of the middle cerebral artery.

The development of the corpus callosum in semilobar and lobar holoprosencephaly.

OBJECTIVE: The objective of this study was to determine whether and how a true corpus callosum develops in milder cases of holoprosencephaly. MATERIALS AND METHODS: The MR scans of seven patients with holoprosencephaly and a callosum-like structure were reviewed. The anatomy of the callosum-like structure and the pericallosal anatomy were evaluated. RESULTS: Six of the seven cases had a posterior corpus callosum. The seventh case was indeterminate because lack of myelination prevented confirmation that the callosum-like structure consisted only of white matter. In each case the posterior corpus callosum formed posterior to white matter which spanned the interhemispheric fissure beneath a layer of cortical gray matter. CONCLUSION: A posterior corpus callosum can develop in holoprosencephaly because the first callosal axons use the white matter of the undivided hemispheres as a bridge to cross the interhemispheric fissure.

Gliosarcoma: MR features.

PURPOSE: Our goal was to characterize the MR features of pathologically documented gliosarcoma and to determine if these features help differentiate gliosarcoma from other intracranial neoplasms. METHOD: MR studies of six patients with pathologically documented gliosarcoma were retrospectively analyzed. RESULTS: The tumors tended to be well defined lesions demonstrating either an inhomogeneous or cystic appearance with surrounding vasogenic edema. All tumors were characterized as primarily intraaxial but abutting a dural surface. On T2-weighted images, all tumors were of intermediate signal intensity with surrounding edema. The signal intensity of the tumor was similar to gray matter but was hypointense relative to other glial neoplasms. Postcontrast T1-weighted images showed intense tumor enhancement, often with a ring-like appearance. The isointense component on the T2-weighted images corresponded to this area of intense enhancement. CONCLUSION: Gliosarcoma exhibits some characteristic MR features. It should be included in the differential diagnosis of any tumor that appears to be intraaxial but abuts a dural surface and is much less hypointense on T2-weighted images than other glial neoplasms.

MR imaging of Creutzfeldt-Jakob disease.

PURPOSE: To describe the magnetic resonance (MR) imaging appearance of Creutzfeldt-Jakob disease (CJD). MATERIALS AND METHODS: MR images obtained in 29 patients who died of CJD (aged 53-77 years at death) were retrospectively reviewed by three neuroradiologists blinded to the diagnosis. RESULTS: Moderate to marked bilateral, symmetrically increased signal intensity was demonstrated in the putamen and caudate nucleus on T2- and proton-density-weighted MR images in 23 patients (79%). In six patients (21%), images showed no major signal intensity abnormalities. T1-weighted images revealed no signal intensity abnormalities and no contrast material enhancement. The degree of atrophy in the cortex and basal ganglia corresponded to the time between onset of symptoms and MR imaging. All patients with a disease duration of longer than 4 months had substantial volume loss. CONCLUSION: Although approximately 20% of the patients did not have MR imaging abnormalities, MR imaging did show signal intensity alterations due to gliosis and spongiform changes early in the course of CJD in the remaining 80%. The demonstration of bilateral areas of increased signal intensity that predominantly affected the caudate nuclei and the putamina on long-repetition-time MR images in an elderly patient with rapidly progressive dementia represents a specific finding and clearly should suggest the diagnosis of CJD.

Treatment of dural sinus thrombosis using selective catheterization and urokinase.

Thrombosis of the cerebral dural venous sinuses, cortical draining veins, and deep cerebral veins is a rare clinical finding. Because of its low incidence and multiple etiologies, the optimum therapy for this condition will only be elucidated by a multicenter, randomized prospective study. At our institution, we favor early and aggressive management of cerebral venous sinus thrombosis with transfemoral, venous intradural infusions of the fibrinolytic agent urokinase. To date, treatment of only 13 patients using this technique has been reported in the English literature. This report adds 12 more such treated patients. Despite the presence of preinfusion infarcts in 5 patients, four of which were hemorrhagic, we incurred no major therapeutic morbidity. Functional sinus patency was achieved in 11 of 12 patients, with our only true failure occurring in an individual with symptoms of at least 2 months' duration. Good to excellent clinical outcome was achieved in 10 of 11 patients (one newborn had inadequate follow-up).

Partial development of the corpus callosum.

PURPOSE: To determine whether the MR findings of callosal dysgenesis suggest that the partially formed corpus callosum in humans is the result of arrested growth or delayed continued development. METHODS: The MR scans of 25 patients with callosal dysgenesis were reviewed to determine whether the observed corpus callosum corresponded to the form and position of a portion of a normal corpus callosum, as suggested by a theory of arrested growth. RESULTS: In 10 of the 25 cases, the partially formed corpus callosum corresponded to a portion of a normal corpus callosum. In the remaining 15 cases, the partially formed corpus callosum was located posterior to the expected location of a normal genu and inferior to the expected location of a normal body. CONCLUSIONS: Corpus callosum dysgenesis in humans may be caused by arrested growth in some cases; in other cases it is most likely caused by delayed continued development that attempts to compensate for earlier abnormalities in the evolution of midline structures.

Intraventricular fibroma: MR and pathologic comparison.

This case report describes clinical, surgical, MR, and pathologic findings of an intraventricular fibroma, a rare, benign mesenchymal neoplasm. Relatively isointense with normal brain parenchyma on T1-weighted images, the tumor exhibited hyperintense signal on T2-weighted pulse sequences and enhanced intensely and homogeneously after intravenous administration of gadopentetate dimeglumine. Choroid plexus papilloma/carcinoma, meningioma, ependymoma, and subependymal giant cell astrocytoma should be included in the differential diagnosis.

Intracranial granulocytic sarcoma: CT, MR, and angiography.

Granulocytic sarcoma is a rare, solid tumor composed of immature granulocytes usually found in association with systemic leukemia in younger patients. We present a case of granulocytic sarcoma occurring in an elderly female with no evidence of systemic leukemia. Computed tomography, MR (with and without Gd-DTPA), and angiography showed features commonly found in meningiomas.

Stroke associated with coronary artery bypass surgery.

Medical records and neuroimaging studies of 30 patients with major neurologic events after coronary artery surgery were reviewed. Two thousand and twenty-nine coronary artery bypass graft operations were performed in our institution between October 15, 1985, and December 27, 1989. Of these, there were 30 documented neurologic events suggesting acute ischemic injury during the intraoperative or the postoperative period. Clinical manifestations included hemiparesis, monoparesis, aphasia, bilateral cortical dysfunction, cortical and brainstem dysfunction, and left homonymous hemianopsia. There were five deaths directly attributable to neurologic injury. Twenty-two patients had a CT scan of the head, of which 15 showed evidence of acute infarction, two suggested watershed lesions from cerebral hypoperfusion, and the remainder showed findings consistent with multiple cerebral emboli or primary intracranial occlusion. Five carotid arteriograms and one digital subtraction arteriogram of the carotids were obtained. Angiographic findings revealed two common carotid artery occlusions, one callosal marginal artery occlusion, and two cases of bilateral high-grade internal carotid stenoses. Our findings support the contention that in patients who suffer cerebral infarction associated with coronary artery bypass grafting, the main mechanism of injury is cerebral embolization rather than cerebral hypoperfusion.

Cell lysis by induction of cloned lambda lysis genes.

The lysis gene region of bacteriophage lambda, including genes S, R, and Rz, was cloned into the plasmid pBH20. In the recombinant plasmid, the lysis genes are expressed under the control of the lacOP region. Induction of this "lysis operon" with the lac inducer, IPTG, under conditions where transcription from the lacOP region is not subject to catabolite repression, results in a sharply defined lysis after 35 min. Premature lysis can be accomplished by cyanide, chloramphenicol, or chloroform, exactly as in bacteriophage lambda infected cells. The lysis gene region of an S- mutant was also cloned into pBH20. Induction of the S- lysis operon has no apparent effect on culture growth; however, large quantities of bacteriolytic activity accumulate intracellularly. Neither cyanide nor chloramphenicol causes lysis in the induced S- clones. Thus premature lysis appears to be entirely an S-dependent phenomenon. A model for the control of lysis in bacteriophage lambda infections is presented in which it is the accumulation of the S gene product in competition with a host "anti-S" protein that determines lysis timing.