Magnetic resonance imaging of intercranial plasmocytic granuloma.

The objective of this study is to determine characteristic magnetic resonance imaging (MRI) features of intracranial plasmocytic granulomas. Pathological confirmation of three patients with intracranial pathologically confirmed plasmocytic granuloma are presented. Clinical records as well pre- and postgadolinium-enhanced images from each patient are reviewed. The location of the abnormalities is compared with previous reported cases of plasmocytic granulomas, to determine if there is a characteristic finding in this disense. The predominance of this abnormality in the pediatric and young adult patient was striking. On T(1)-weighted MRI, plasmocytic granulomas appear as hypointense lesions, with isointense appearance on T(2) images, and significant, variable patterns of enhancement after the infusion of gadolinium. Typically, the lesion is infiltrating, and causes little mass effect. A dural based lesion, as well as a sellar region abnormality and an infiltrating cortical lesion with little mass effect in the pediatric or young adult age group may lead the observer to suspect the diagnosis of plasmocytic granuloma.

Pulsatile tinnitus associated with a laterally placed sigmoid sinus.

We describe a case of subjective pulsatile tinnitus associated with a laterally placed sigmoid sinus. CT showed an enhancing eroding through the medial wall of the right mastoid. Two-dimensional time-of-flight MR angiography and conventional cerebral angiography revealed the tortuous and laterally deviated sinus.

Selective embolization of glomus jugulare tumors.

Four patients with grade C or D(1) glomus jugulare tumors who underwent preoperative highly selective embolization followed by infratemporal fossa removal of their tumors were compared to three patients undergoing surgery alone with respect to intraoperative blood loss, operative time, cranial nerve palsy, length of hospitalization, and perioperative complications. Embolized patients demonstrated a marked reduction in blood loss (650 vs 1375 cc) compared with the nonembolized group. Operative time was shortened (by 51 minutes). Facial nerve function did not appear related to embolization but was directly related to intraoperative nerve manipulation. Hospital stay, perioperative complications, and lower cranial nerve palsies were not related to embolization.

Experimental chronic compressive cervical myelopathy.

A canine model simulating both cervical spondylosis and its results in delayed progressive myelopathy is presented. This model allowed control of compression, an ongoing assessment of neurological deficits, and evaluation using diagnostic images, frequent electrophysiological tests, local blood flow measurements, and postmortem histological examinations. Subclinical cervical cord compression was achieved in 14 dogs by placing a Teflon washer posteriorly and a Teflon screw anteriorly, producing an average of 29% stenosis of the spinal canal. Four dogs undergoing sham operations were designated as controls. Twelve of the animals undergoing compression developed delayed and progressive clinical signs of myelopathy, with a mean latent period to onset of myelopathy of 7 months. Spinal cord blood flow studies using the hydrogen clearance method showed a significant transient increase in blood flow immediately after compression and a decrease before sacrifice. Somatosensory evoked potential studies indicated progressive deterioration during the period of compression. Magnetic resonance images revealed intramedullary changes. Histological studies showed abnormalities overwhelmingly within the gray matter, including changes in vascular morphology, loss of large motor neurons, necrosis, and cavitation. Axonal degeneration and obvious demyelination were rarely seen. The most profound morphological changes occurred at the site of greatest compression. It is proposed that a momentary arrest of microcirculation occurs during extension of the neck because of loss of the reserve space in the compromised spinal canal. This microcirculatory disturbance is predominant in the watershed area of the cord and mainly affects the highly vulnerable anterior horn cells, leading to neuronal death, necrosis, and eventual cavitation at the junction of the dorsal and anterior horns. Additional supportive evidence of this hypothesis was derived from the literature.

Comparison of computerized tomography and magnetic resonance imaging for the postoperative assessment of residual acoustic tumor.

Ten patients with surgically confirmed residual cerebellopontine angle neuromas, imaged by both computerized tomography (CT) with iodine contrast and magnetic resonance (MR) with and without gadolinium enhancement, are reviewed to identify the strengths and limitations of MR as compared with CT imaging. MR imaging offers superior anatomic resolution in multiple imaging planes without ionizing radiation, but it is expensive and has adverse effects on some patients. CT imaging offers good anatomic resolution, but in only one or two planes. CT is both less expensive and generally well tolerated, but allergy to the iodine contrast is not uncommon. The cases presented demonstrate the adequacy of CT imaging of residual tumor. However, in some cases MR imaging provided important additional detail. MR imaging also demonstrated postoperative changes within the brain stem and cerebellum. In our experience, CT imaging remains a satisfactory, unambiguous approach to the assessment of known postoperative residual cerebellopontine angle neuromas. MR imaging provides superior resolution, however, and should be used when better definition of tumor detail is needed for management decisions or when multiple follow-up scans are anticipated, so that the exposure to ionizing radiation is limited. MR is also useful to investigate postoperative neurologic dysfunction. Postoperative changes and residual tumors are more difficult to interpret on MR than on CT. Guidelines are proposed to help distinguish residual tumor from postoperative changes and scarring.

Neurovascular complications of cocaine abuse.

A 3-year prospective study of 31,081 admissions to an inner-city, emergency trauma hospital revealed 33 patients less than or equal to 45 years of age who had a total of 35 acute neurovascular events (infarction or hemorrhage) related to cocaine abuse (3% of the total 979 cocaine-related admissions). Fifty-four percent of the events were ischemic, and 46% were hemorrhagic. Six patients died. The majority (63%) of ischemic events were hemispheric and subcortical in distribution. Eleven of 13 angiograms were abnormal (five aneurysms and two arteriovenous malformations were identified). No case of "vasculitis" was seen. Seventy percent of the patients exclusively abused crack cocaine, and 94% of the neurovascular events were related to its use. No first-time cocaine users were identified. During the last year of the study, 29% of the 558 cocaine-related admissions were psychiatric admissions, and most (58%) were for treatment of depressive illness (34 patients were admitted for attempted suicide).

MR imaging of compressive myelomalacia.

The authors studied retrospectively 42 patients with the magnetic resonance (MR) diagnosis of myelomalacia. Depending on MR findings, the patients were grouped into early, intermediate, and late stages of myelomalacia. Early stage myelomalacia patients presented with high intensity signal changes on T2-weighted images involving the width of the affected cord. The intermediate stage patients were characterized by varying degrees of cystic necrosis of the central gray matter, better seen on T2-weighted images. Central cystic degeneration, syrinx formation, and atrophy were prominent features of the late stage of myelomalacia. Ten patients had follow-up MR examinations within 6 months of initial imaging. Two of the four early stage myelomalacia patients showed improvement in the repeat studies. The follow-up scans of the six intermediate and late stage myelomalacia patients showed either no change or progression of disease. Early stage myelomalacia may be reversible, depending on the severity of the initial spinal cord injury. Magnetic resonance can serve as a useful tool in the assessment and management of myelomalacia patients.

MR imaging of lytic changes in Paget disease of the calvarium.

The authors present two patients with Paget disease, both showing lytic changes in the calvarium. On T1 contrast sequences, the first patient demonstrated an extraaxial soft tissue mass in the temporooccipital region. This abnormality was hypointense to the adjacent normal diploic tissue. The second patient demonstrated a hypointense frontal abnormality on the T1-weighted sequence. Intracranial extension of this lesion was associated with lysis in otherwise mixed signal pagetoid bone. The first patient had osteoclastic Paget disease or osteoporosis circumscripta. The second patient had sarcomatous degeneration.

Embolization in cataclysmal hemorrhage caused by squamous cell carcinomas of the head and neck.

Cataclysmal hemorrhage occurred in eight patients with known aggressive squamous cell tumors of the head and neck. Angiography showed neovascularity, narrowing, beading of affected arteries, and pseudoaneurysms. Postembolization residual stump formation was seen in a few patients. A total of 11 embolization procedures were performed in these eight patients. Embolization materials included polyvinyl alcohol, isobutyl-2-cyanoacrylate, and detachable balloons. Survival times ranged from 5 to 274 days, with no deaths as a direct result of hemorrhage. Only one severe complication following embolization was noted.

Phase II study of aziridinylbenzoquinone (AZQ: NSC-182986) in the treatment of malignant gliomas recurrent after radiation. Preliminary report.

Seventeen patients with malignant gliomas recurrent after chemotherapy and/or radiation failure were treated with aziridinylbenzoquinone (AZQ) at a dose of 20-15 mg/M2 weekly for four weeks followed by a two week rest. Regression of disease was observed in four patients, 4/17 (24%) for 35, 15+, 40+, and 10 weeks. Toxicity was limited to moderate reversible myelosuppression. AZQ in this dose and schedule has limited but definite activity in patients with malignant gliomas progressive after primary radiation therapy failure.

Histopathologic effects of transarterial bucrylate occlusion of intracerebral arteries in mongrel dogs.

Bucrylate was injected directly into the cerebral cortical arteries of mongrel dogs. Preparations for light and electron microscopy were obtained from 5 min to 5 months after the introduction of the polymer. A mixed pattern of damage to arterial endothelium was seen, including electron microscopic documentation of stripping away of the endothelium. Acute effects include a subocclusive thrombogenic matrix, which causes partial or complete thrombosis. The long-term reactions are those of a chronic inflammatory response to a foreign body.

Arteriovenous vertebral fistulae: cure by combination of operation and detachable intravascular balloon.

The direct surgical treatment of vertebral arteriovenous fistulae (AVF) presents serious difficulty and risk. Techniques for intravascular occlusion or embolization have made the treatment of AVF safer and effective. However, the occlusion of an AVF involving the segment where the vertebral vein becomes a single vessel may result in pulmonary emoblization by the occluding material. A combined procedure involving ligation of the vertebral vein and detachable balloon occlusion of the fistula was used in two instances without complications and with complete cure of the AVF.

Evaluation of the inferior vena cava by sonography and venography in children with renal and hepatic tumors.

Ultrasonography was used to examine 81 children with intra-abdominal or retroperitoneal malignancies for tumor extension into the inferior vena cava (IVC). In seven of the 18 patients with Wilms tumors and three of the seven patients with hepatic tumors, the IVC ws sonographically abnormal. Venography was also performed in five patients with Wilms tumors. However, percutaneous transfemoral venacavography did not always allow differentiation between extrinsic compression and intracaval tumor. It is suggested that venacavography, when necessary, should be performed via the brachial vein route and that the catheter be advanced into the right atrium. If an injection in this chamber does not result in enough reflux into the retrohepatic IVC for adequate evaluation, the catheter should be advanced into the IVC and a second injection made. However, ultrasonography is the preferred modality for evaluation of the IVC in children because it is the most accurate method and is noninvasive. Real-time ultrasonography makes it possible to distinguish between tumor extension into the lumen of the IVC and extrinsic compression of the vessel.

Craniofacial mucormycosis: computed tomographic and angiographic findings in two cases.

Two cases of craniofacial mucormycosis are presented, stressing computed tomographic (CT) and angiographic findings. In the first case, successful embolization of a sphenopalatine artery pseudoaneurysm is shown. The second case demonstrates CT findings of ethmoidal sinus and frontal lobe inflammatory change. Ophthalmic artery occlusion is show. Obstructive venous changes within the orbit and cavernous sinus are displayed by means of orbital venography.

Orbital pseudotumor: association of orbital vein deformities and myositis.

Twenty adult patients with orbital pseudotumor were studied with orbital venography and magnification arteriography. Computed tomography (CT) scans were obtained in 14 patients. Occlusive and constrictive changes of the proximal segments of the superior ophthalmic veins were the most frequent vascular abnormalities. The affected ophthalmic arteries were often attenuated but not occluded. Myositis and surrounding connective tissue inflammatory changes are thought to result in sufficient mass effect to cause the venous stasis with narrowing and subsequent occlusion. Such venographic changes are not distinctive for orbital pseudotumor but may also be seen in cases of thyrotoxicosis, Tolosa-Hunt syndrome, and orbital tumors.