Efficacy of gadolinium administration in magnetic resonance imaging screening of patients with complex partial seizures and results of a normal neurologic examination.

RATIONALE AND OBJECTIVES: Magnetic resonance imaging has become a standard screening tool in the evaluation of patients with complex partial seizures. This study prospectively addresses the efficacy, if any, of routinely adding gadolinium-enhanced images to routine T2-weighted images in patients with a normal neurologic examination. METHODS: One hundred consecutive patients with electroencephalogram and clinical evidence of complex partial seizures and no other neurologic abnormalities were examined prospectively with axial and coronal T2-weighted spin-echo images, followed by axial and coronal gadolinium-enhanced T1-weighted scans. RESULTS: The scans in 73 patients were interpreted as normal, 14 had nonspecific white matter lesions, 5 had asymmetry of the temporal horns, and 2 had asymmetric signal intensity in the temporal lobes, and the scans in 6 showed abnormal gadolinium enhancement. Of the lesions in the six patients whose scans showed abnormal enhancement, four were seen well on the T2-weighted images. Of the remaining two, one was a small cerebellar venous angioma, and the other, a probable tiny convexity meningioma. One temporal lobe glioma seen on the T2 scans did not enhance with gadolinium. CONCLUSIONS: Routine administration of gadolinium does not appear to be of benefit in imaging patients with complex partial seizures who are otherwise neurologically normal.

Embolization of intracranial aneurysms with Guglielmi detachable coils augmented by microballoons.

We describe two cases in which balloons were used to aid in the occlusion of intracranial aneurysms with Guglielmi detachable coils. In both patients, initial attempts to place coils within the aneurysmal sac failed, as the loops of the coil repeatedly protruded through a wide aneurysmal neck into the parent vessel. Temporary balloons placed across the neck of these small, wide-necked aneurysms, the bridging balloon technique, effectively narrowed the necks, providing support for the formation of a proper coil basket, which was not possible without the balloon. Follow-up studies at 1 year showed good results in both patients.

Fenestration of intracranial arteries with special attention to associated aneurysms and other anomalies.

PURPOSE: To determine the association of intracranial arterial fenestration and aneurysms. METHODS: We retrospectively reviewed 5,190 cerebral angiogram reports and identified 37 patients with arterial fenestrations. RESULTS: These 37 patients had 38 fenestrated arteries: 16 basilar, 10 vertebral, nine middle cerebral, and three anterior cerebral arteries. Seven of these patients had a total of 13 aneurysms, although only one aneurysm was at the site of a fenestration. The remaining aneurysm patients had fenestrations as unassociated findings. Other anomalies detected were two azygous anterior cerebral arteries, on dural arteriovenous shunt of the cavernous sinus, one extracranial arteriovenous fistula, and one developmental venous anomaly (venous angioma). None of the fenestrations were in the vessels directly involved with these associated lesions. The incidence of aneurysm at the fenestration was 7% (one in 16) for basilar artery fenestrations. Considering all fenestrations, the incidence of aneurysm at the site of fenestration was 3%. CONCLUSION: Our data show that the association of a fenestration with an aneurysm at the fenestration site is not different from the typical association of circle of Willis bifurcations with saccular aneurysms.

Importance of absence of CSF pulsation artifacts in the MR detection of significant myelographic block at 1.5 T.

MR imaging was performed on 21 patients who had high-grade myelographic block due to various diseases in all spinal compartments (extradural, intradural/extramedullary, and intramedullary) and in all portions of the spinal canal (cervical, thoracic, and lumbosacral). Loss of CSF pulsation artifacts due to significant compression of the spinal cord was demonstrated on non-motion-compensated T2-weighted examinations in each case. We believe that the absence of such artifacts on these sequences indicates significant spinal cord compression in patients without classic signs and symptoms of cord compression but with intraspinal disease identified on T1-weighted studies.

Angiographic features of gliosarcoma.

Gliosarcoma is a brain neoplasm that is being recognized with increasing frequency. We discuss the radiographic findings in 14 pathologically proven cases. At angiography in nine cases, four showed mixed dural and pial vascular supply to the lesion. Early cortical venous drainage, irregular tumor vessels, and a prominent vascular stain with well-defined tumor margins were seen in the majority of cases. CT showed an irregular enhancing rim surrounding a necrotic center in 14 cases. Most lesions were peripherally located and invaded dura.

Paraganglioma of the temporal bone: role of magnetic resonance imaging versus computed tomography.

Paragangliomas, also known as glomus tumors or chemodectomas, are tumors arising from chemoreceptor tissue (paraganglia), which are neural crest in origin and found in higher concentration along the glossopharyngeal and vagal cranial nerve. Three types of paragangliomas are related with the temporal bone: glomus tympanicum, glomus jugulare, and glomus vagale. The role of computed tomography (CT) and magnetic resonance imaging (MRI) in diagnosing these types of tumors is discussed, along with the importance of arteriography in aiding the diagnosis and treatment. This article discusses the choice between CT and MR based on clinical symptoms and tumor location, and illustrates the newest CT, MR, and angiography applications. A brief discussion on treatment options is given.

Ultrasonic features of two cases of spinal cord hemangioblastoma.

Two patients with proven intramedullary spinal cord hemangioblastomas were examined with intraoperative ultrasound. The ultrasonic features of a hyperechoic intramedullary mass accompanied by nearby cysts and, in one case, by a syrinx correspond with well-known pathological and computed tomographic descriptions of these tumors. Ultrasonic guidance enabled the surgeon to identify the exact location of the tumors and to proceed with the surgery, limiting the dissection to the area detected. The ultrasound also revealed cysts associated with the tumors, thus providing valuable information to guide the progress of surgery.

MRI of hemorrhagic choroid plexus cyst.

An unusual case of hemorrhage within a cyst in the choroid plexus of the lateral ventricle is presented. Choroid plexus cysts are commonly found incidentally on imaging studies, particularly MRI, where their characteristic appearance produces little diagnostic difficulty. In this case, high signal intensity of the cyst contents on T1-weighted images and apparent hemosiderin deposition in the cyst wall, not previously described, represented a dramatic change from a study 10 weeks previously and allowed a presumptive diagnosis of hemorrhage into the cyst, a presumption further supported by the changes in signal 20 weeks later.

Absence of the supraclinoid internal carotid artery in association with intracranial aneurysms.

We report a case of absence of the supraclinoid segment of the left internal carotid artery associated with hypoplasia of the ipsilateral internal carotid artery and anterior communicating artery aneurysm formation. We discuss the embryology probably responsible for this anatomical variant and show the imaging findings.

Imaging-guided injection techniques with fluoroscopy and CT for spinal pain management.

Local spinal pain and radiculopathy are common conditions that debilitate millions of Americans annually. Most cases are successfully treated conservatively with rest or physical therapy. Chiropractic manipulation or, in some cases, surgery may also be performed. Percutaneous injection has been used for spinal pain management for many years, but many of these procedures have historically been performed without imaging guidance. Recently, however, newer minimally invasive, imaging-guided percutaneous techniques have been added to the list of available treatment options for spinal pain. Imaging-guided techniques with fluoroscopy or computed tomography increase the precision of these procedures and help confirm needle placement. Cervical, thoracic, lumbosacral, and sacroiliac pain can be evaluated and treated safely and effectively with injections of local anesthetics or long-acting steroids into facet joints, sacroiliac joints, selective nerve roots, spondylolytic areas, and the epidural space. Because imaging-guided techniques appear to provide better results and reduce complication rates, they are becoming more popular despite controversy regarding their effectiveness. Controversy will continue to surround these imaging-guided techniques until large, double-blinded studies become available. In the meantime, there is an increased demand for these procedures from referring physicians, and it is important to be able to safely perform them with a minimum of patient discomfort.

Intraventricular primary neuronal neoplasms: CT, MR, and angiographic findings.

Intraventricular primary cerebral neuroblastoma and the more differentiated intraventricular neurocytoma are primary neuronal tumors that share common radiological characteristics. This article describes the imaging characteristics of these rare tumors using CT, MR, and angiography. We present one case of each neoplasm.

Epidural lipomatosis.

The authors report six new cases of epidural lipomatosis--a rarely described entity characterized by increased extradural fat within the spinal canal causing compression of the spinal cord and neurologic deficits. Five of the six patients had a history of chronic steroid use. Myelography of the thoracic spine, followed by computed tomography (CT), was performed in five patients, and magnetic resonance (MR) imaging was done in three. Myelographic findings were abnormal in three patients and normal in two, compared with those of postmyelography CT, which revealed increased accumulation of extradural fat in all five patients. In the three patients in whom it was performed, MR imaging also showed the increased spinal canal fat. Four patients underwent surgery, which revealed an increased amount of histologically normal, unencapsulated fat in all cases. The diagnosis of epidural lipomatosis should be based on a combination of clinical, imaging, surgical, and histologic findings. If the clinical suspicion is high, even if results of myelography are normal, further evaluation with post-myelography CT or MR imaging should be considered.