Biomedical subjects
Publications and source records attributed to R S Pinto.
A variety of histologic subtypes of tumor may affect the thalamus and the hypothalamus in the pediatric population. These tumors have radiologic features that are useful in predicting pathology. We discuss the radiologic findings of childhood thalamic and hypothalamic tumors and provide imaging examples.
Intracranial and intraspinal ependymomas are uncommon tumors of the central nervous system. These tumors have a variety of imaging characteristics, some of which are fairly specific for ependymoma. We discuss the MRI features of ependymomas for each of the typical locations within the neuraxis, and provide MR imaging examples.
PURPOSE: Our purpose was to describe the MR imaging features in a series of spinal intramedullary gangliogliomas and to compare these findings with the MR features of intramedullary astrocytomas and ependymomas. METHODS: A retrospective analysis was performed of 76 MR examinations in 27 patients with histologically proved spinal ganglioglioma; these were then compared with imaging findings in a representative sample of histologically proved spinal cord astrocytomas and ependymomas. RESULTS: Statistically significant observations regarding spinal gangliogliomas included young age of the patients (mean, 12 years), long tumor length, presence of tumoral cyst, presence of bone erosion and scoliosis, absence of edema, presence of mixed signal intensity on T1-weighted images, and presence of patchy enhancement and cord surface enhancement. A trend (not statistically significant) was noted for holocord involvement and lack of magnetic susceptibility. CONCLUSION: Spinal ganglioglioma can be strongly suspected if MR images reflect the above criteria; however, the ultimate diagnosis still depends on radical resection and appropriate histopathologic investigation.
Although previously unreported, neurologic compromise may occur secondary to anomalies of the cervical spine in the oculoauriculovertebral spectrum. Medical records and cephalograms were reviewed from 18 patients with classic Goldenhar syndrome and from 18 normal adults. One patient, a 22-year-old man, had experienced a 5-year history of progressive neurologic compromise from basilar impression; the remaining 17 patients were asymptomatic. Radiographic evidence of cervicovertebral fusion was documented in 11 of 18 patients (61 percent). Fusion occurred at every cervical level other than the atlantoaxial joint. Radiographic indices that characterize the cranial base were not significantly different between asymptomatic Goldenhar patients and normal adults. Posterior inclination of the odontoid with respect to the foramen magnum appears to be the best indicator that a patient is at risk for basilar impression. Careful radiographic evaluation may indicate which patients require more careful surveillance with periodic neurologic examination and CT and/or MRI scans.
BACKGROUND AND PURPOSE: To determine the accuracy of magnetic resonance angiography in assessing patients with cerebrovascular disease, we performed a study comparing the results of conventional cerebral angiography, duplex scanning, and magnetic resonance angiography. METHODS: From 42 patients, a total of 25 carotid arteries were evaluated by all three techniques. The studies were independently read and sorted into five categories according to the degree of stenosis: 0-15%, normal; 16-49%, mild; 50-79%, moderate; 80-99%, severe; and totally occluded. RESULTS: Magnetic resonance angiography correlated exactly with conventional angiography in 39 arteries (52%); duplex scanning correlated with conventional angiography in 49 cases (65%). Compared with conventional angiography, both magnetic resonance angiography and duplex scanning tended to overread the degree of stenosis. The most critical errors associated with magnetic resonance angiography were three readings of total occlusion in vessels found to be patent on conventional angiograms. CONCLUSIONS: Although magnetic resonance angiography offers great hope of providing high-quality imaging of the carotid artery with no risk and at less cost, data from this study suggest that misreading the degree of stenosis, or misinterpreting a stenosis for an occlusion, could lead to errors in clinical decisions. Guidelines for use of magnetic resonance angiography in a clinical setting are offered.
Gadolinium-enhanced magnetic resonance (MR) imaging studies of 30 histologically proved cranial meningiomas revealed a linear enhanced structure or "tail" extending away from the tumor mass along the dural surface in 18 cases (60%). Contrast material-enhanced computed tomographic studies available in 10 of these 18 cases did not depict this structure. Characteristic features of this MR finding were reviewed, and criteria were defined to distinguish this tail from other enhanced structures. To assess the differential diagnostic value of this finding, gadolinium diethylenetriaminepentaacetic acid-enhanced MR studies of a control group of other extraaxial lesions as well as superficial intraaxial tumors that abut the meninges were reviewed. These cases failed to show this MR feature. Pathologic correlation was available in three meningiomas with the finding of a tail, and these demonstrated meningothelial tumor nodules in the samples taken from areas corresponding to the enhanced regions on MR images. This is in agreement with other recent pathologic studies of the dura mater surrounding meningiomas. The authors believe that the linear enhanced structure described may represent tissue containing tumoral nodules. Awareness of this MR sign may be useful in distinguishing meningiomas from other lesions and in planning total resection of the infiltrated dura mater.
A dose-escalation study of the calcium ion entry blocking drug nicardipine was performed using large dose infusions in 67 patients with recent aneurysmal subarachnoid hemorrhage (SAH). A safe, potentially therapeutic dose of the drug was determined. Patients admitted within 7 days of SAH from a documented cerebral aneurysm were entered into the study if no spasm was present on the initial angiogram. Nicardipine was administered as a continuous intravenous infusion throughout the 14-day period after SAH, regardless of the timing of surgery. To determine the safest possible dose, nicardipine was administered at seven dose levels from 0.01 to 0.15 mg/kg/hr. The total daily doses ranged from 27.7 mg to 375.0 mg. A follow-up angiogram was carried out on all 67 patients 7 to 10 days after SAH. Computerized tomography and neurological examinations were used to determine the presence of cerebral infarction. No major adverse effects, unexpected reactions, or permanent sequelae could be attributed to nicardipine. A decline in blood pressure was noted following administration of the drug. This occurred more frequently among patients given the largest dose but did not produce clinical problems or require discontinuation of the drug. Favorable outcomes were noted in 52 patients (78%). Vasospasm was found by arteriography in 31 patients (46%). A dose-related trend was noted: only eight (24%) of 33 patients treated at the highest dose level (approximately 10 mg/hr) developed arteriographic evidence of vasospasm. Symptomatic vasospasm was diagnosed in only two (6%) of 33 patients treated with this dose. Of the 34 patients receiving the lower dose levels, angiographic spasm was observed in 68% and symptomatic vasospasm in 27%. No deaths due to vasospasm occurred. Nicardipine appears to prevent both vasospasm and cerebral ischemia after SAH. A multicenter randomized double-blind trial to test this hypothesis is planned.
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Fifteen magnetic resonance (MR) imaging studies in 16 patients with intramedullary spinal cord lesions were correlated with surgical findings in all patients and with results of intraoperative spinal sonography (IOSS) in eight. Tumor extent was defined accurately in all but two patients by MR imaging; these lesions were found at surgery to have been underestimated by one to two vertebral body segments. Most tumors had lengthened T1 and T2 relaxation times. Intratumoral cysts were detected by MR imaging in one of eight cases, and rostral and caudal cysts were defined in only two of ten cases. The poor detection rate is attributed to poor spatial and contrast resolution. Preoperative MR imaging to define the extent of cord enlargement and IOSS to define cystic structures appears to be the optimal method of tumor management pending our further study.
The presence of periventricular high signal lesions and ventricular signal void was tabulated and compared in three groups: patients with unshunted hydrocephalus (n = 24), cerebral atrophy (n = 14), and a subgroup of treated hydrocephalus subjects studied both pre- and post-shunting (n = 6). We found that T2 high signal lesions and ventricular signal void are common in both hydrocephalus and atrophy and are of no value in distinguishing between the two. The pre-treatment presence or absence of periventricular high signal lesions and signal void were of no use in predicting the clinical outcome of shunting in hydrocephalus.
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Calcification of the posterior longitudinal ligament occurs in about 3% of adults in Japan, and in about 0.7% of hospitalized adults with spinal symptoms in the United States. The condition may be asymptomatic, however, in patients with a stenotic spinal canal or when the calcification is large, it may cause compression of the spinal cord and myelopathy. The radiographic diagnosis is made when a band of calcification is noted in the spinal canal directly posterior to the vertebral bodies. Lateral tomograms of the spine are helpful for detection and measurement of the exact thickness of the calcification. Computed tomography is particularly helpful because it reveals the thickness and the extent of lateral extension of the calcification, as well as the size of the spinal canal and the extent of its narrowing by the calcification. Seventeen patients evaluated by computed tomography are reported.
Thrombosed arteriovenous malformations (AVMs) in children are rare lesions that may present with headaches or a seizure disorder. Thirteen patients (4 months to 21 years of age) with this lesion were examined with computed tomography (CT). In 11 patients surgical confirmation was obtained, and the other two patients were examined with follow-up CT scans. Angiography either showed an avascular mass (7/13) or was negative (6/13). CT showed a lobulated lesion (8/13), peripheral location (11/13), and minimal surrounding edema (8/13). All of the lesions were hyperdense prior to the administration of contrast material and all enhanced either slightly or not at all following contrast material administration. It is concluded that these characteristic CT features aid in making the diagnosis of thrombosed AVM. The major differential diagnosis is small intracerebral neoplasm.
Iopamidol (280 mgI/ml) was compared with Conray 60 (iothalmate meglumine, 282 mgI/ml) during selective and superselective cerebral arteriography. Twelve patients were examined, and a total of 51 selective injections were compared. Iopamidol produced significantly less pain and burning than Conray 60 and caused no patient motion.
All complications were recorded from the initial 2488 cases studied with digital intravenous angiography (DIVA) at New York University Medical Center. Mechanisms of producing these reactions were categorized into procedure-related, contrast-medium-related, or disease-related. The complications included extravasation of contrast material into the arm (11 patients) and mediastinum (two), acute pulmonary edema (four), hypotension (23), thrombophlebitis (two), and grand mal seizure (one). Recommendations are made that would allow DIVA to be performed more safely.
A patient with signs of brainstem compression and hydrocephalus is reported. The clinical picture suggested a posterior fossa neoplasm. Computed tomography, however, proved highly accurate in making the diagnosis of a giant, partially thrombosed vertebrobasilar aneurysm. The radiographic appearance of this entity is summarized and pathologic correlation is offered.
A case of brain stem infarction after chiropractic manipulation of the cervical spine is presented. Proposed mechanisms and sites of possible arterial injury are discussed. A diagnosis of vertebral artery occlusion was made using conventional brachial angiography. Digital intravenous angiography, a relatively new and less invasive vascular imaging technique which was used as an adjunct for evaluating the remainder of the cervicocephalic vessels, documented the vertebral occlusion. Chiropractic manipulation, which is increasing in popularity, may be a cause of potentially devastating neurologic disease.
A case of brain stem infarction after chiropractic manipulation of the cervical spine is presented. Proposed mechanisms and sites of possible arterial injury are discussed. A diagnosis of vertebral artery occlusion was made using conventional brachial angiography. Digital intravenous angiography, a relatively new and less invasive vascular imaging technique which was used as an adjunct for evaluating the remainder of the cervicocephalic vessels, documented the vertebral occlusion. Chiropractic manipulation, which is increasing in popularity, may be a cause of potentially devastating neurologic disease.