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Biomedical subjects

B P Drayer

Publications and source records attributed to B P Drayer.

At least 19 recordsLinked to original sources
PubMed1992

Carotid artery stenosis: clinical efficacy of two-dimensional time-of-flight MR angiography.

To assess the clinical efficacy of two-dimensional time-of-flight magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis, a group of patients was evaluated in which 73 vessels were studied with both MR and conventional angiography. Four experienced neuroradiologists each scored both the MR and conventional angiograms in a blinded manner by using a standardized scoring scheme. Comparison of the scores revealed a high degree of correlation. In particular, MR angiography served to discriminate reliably between mildly narrowed and severely narrowed or occluded vessels. Furthermore, severe stenoses were accurately discriminated from occlusions in all cases. MR angiography is a robust and accurate modality for the characterization of carotid artery stenosis. It is useful in conjunction with routine MR imaging of the brain in the evaluation of the patient with suspected carotid arterial disease.

Carotid Arteries↗
PubMed1992

Intracranial vascular stenosis and occlusion: evaluation with three-dimensional time-of-flight MR angiography.

To assess the usefulness of magnetic resonance (MR) angiography in the characterization of intracranial arterial stenosis and occlusion, a three-dimensional time-of-flight method was compared with conventional angiography in 214 vessels in 29 patients. Studies were independently interpreted by two neuroradiologists who scored each vessel as normal, narrowed, or occluded. Overall, 97% of normal vessels and 100% of occlusions were correctly graded. Sixty-one percent of stenoses were graded correctly; the remainder were graded as normal. The portions of the intracranial vessels near the skull base and especially the paracavernous and supraclinoid segments of the internal carotid arteries were areas of frequent over- and underestimation of stenosis due to the presence of dephasing artifacts. In patients with stenosis or occlusion, MR angiography also provided information regarding the presence of collateral flow in the circle of Willis. When used in conjunction with MR imaging of the brain and MR angiography of the extracranial carotid arteries, intracranial MR angiography allows a more complete evaluation of the patient with symptoms of cerebral ischemia or infarction.

Adolescent↗
PubMed1991

Clinical safety and efficacy of gadoteridol: a study in 411 patients with suspected intracranial and spinal disease.

In this phase III study, 411 adult patients with suspected intracranial or spinal disease underwent magnetic resonance (MR) imaging before and after intravenous injection of 0.1 mmol/kg gadoteridol (gadolinium 1,4,7-tris [carboxymethyl]-10-[2'-hydroxypropyl]-1,4,7,10-tetraazacyclododecane+ ++). MR images were evaluated by a single unblinded reader at each of 27 sites; the diagnosis was confirmed with one of nine imaging or surgical procedures within 8 weeks before or after MR imaging. After injection, no clinically significant changes were noted in laboratory values, physical examination, or vital signs. Adverse clinical events possibly or probably associated with injection of gadoteridol were seen in 18 of 411 patients (4.4%); the most common were dysgeusia and mild nausea, and all abated without residual effects. MR images enhanced with gadoteridol in patients with confirmed disease provided more diagnostic information than unenhanced images in 128 of 175 brain examinations (73.1%) and 93 of 137 spinal examinations (67.9%). A change in diagnosis because of additional information from contrast-enhanced images was considered likely in 63 of 214 cranial and 54 of 161 spinal studies.

Adult↗
PubMed1991

Magnetic resonance imaging of the transverse atlantal ligament for the evaluation of atlantoaxial instability.

Twenty normal human subjects and 14 patients with upper cervical spine pathology were studied with axial high-field magnetic resonance (MR) imaging to examine the transverse atlantal ligament. Gradient-echo MR imaging pulse sequences provided reliable visualization of the transverse ligament, which exhibited low signal intensity and extended behind the dens between the medial portions of the lateral masses of C-1. The MR imaging characteristics of the transverse ligament were verified in clinical studies and in postmortem specimens. The clinical MR examinations defined 27 normal ligaments, three ligament disruptions, and four stretched rheumatoid ligaments. Atlantoaxial instability associated with transverse ligament rupture or ligamentous laxity required internal fixation. In contrast, fractures of C-1 or C-2 or atlantoaxial rotatory dislocations associated with an intact transverse ligament healed without instability or nonunion. The transverse ligament is the primary stabilizing component of C-1. The treatment of atlantoaxial instability has previously been based on criteria drawn from computerized tomography or plain radiographic studies, which only indirectly assess the probability of rupture of the transverse ligament. It is concluded that MR imaging accurately depicts the anatomical integrity of the transverse ligament. After transverse ligament failure, the remaining ligaments of the craniovertebral junction are inadequate to maintain stability. The presence of ligament disruption should be considered as a criterion for early fusion.

Arthritis, Rheumatoid↗
PubMed1991

Cavernous malformations and capillary telangiectasia: a spectrum within a single pathological entity.

Cerebral vascular malformations have traditionally been divided into four categories: arteriovenous, venous, cavernous, and capillary telangiectases. A controversy exists about separating the latter two lesions into separate entities. Critics claim the distinction is arbitrary but have been unable to present convincing evidence linking the two types of lesions. We have reviewed the histories of 20 patients with cavernous malformations and have analyzed the clinical, radiographic, and surgical-autopsy data associated with these lesions. In some patients, multiple lesions, including cavernous malformations, capillary telangiectases, and transitional forms between the two, were identified. Based on this analysis, we conclude that capillary telangiectasia and cavernous malformations represent two pathological extremes within the same vascular malformation category and propose grouping them as a single cerebral entity called cerebral capillary malformations.

Capillaries↗
PubMed1990

Gliomas: classification with MR imaging.

The findings at magnetic resonance (MR) imaging in a group of 36 pathologically verified supratentorial gliomas were analyzed and compared with the biopsy diagnoses (a) to determine whether MR imaging could be used to classify astrocytic-series tumors into a three-tiered system of low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme; and (b) to evaluate MR imaging features that may aid in this classification. The MR characteristics evaluated were crossing of the midline, edema, tumor signal heterogeneity, hemorrhage, border definition, cyst formation or necrosis, and mass effect. The statistically significant MR characteristics (positive predictors) were mass effect (P = .0000) and cyst formation or necrosis (P = .0512). The MR accuracy rate approached that of neuropathologic diagnosis, which is subject to sampling errors. MR imaging may serve as an adjunct in case management when the clinical course and MR findings appear to be at odds with the neuropathologic diagnosis.

Anaplasia↗
PubMed1990

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging.

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.

Aged↗
PubMed1989

Gadolinium-DTPA enhancement of a recurrent intramedullary ependymoma: a case report.

Magnetic resonance images enhanced with the paramagnetic contrast agent gadolinium-DTPA accurately differentiated a recurrent intramedullary spinal cord ependymoma from surrounding postoperative and postirradiation spinal cord tissue changes, thereby facilitating total excision of the lesion. The illustrative case and the merits of enhanced magnetic resonance imaging are presented.

Contrast Media↗
PubMed1989

Human cerebral gliomas: correlation of postmortem MR imaging and neuropathologic findings.

Findings from T2-weighted magnetic resonance (MR) images obtained of postmortem, in vitro human brain glioma specimens were correlated with histologic findings from whole-brain sections. Eighteen cases were categorized as untreated (n = 6), in remission after surgery and radiation therapy (n = 2), or recurrent (n = 10). Findings from MR images generally correlated well with the histologic extent of untreated tumors in white matter; the heterogeneous appearance of glioblastomas multiforme distinguished them from less malignant gliomas. Subpial spread and tumor in the subarachnoid space were not visualized. The extent of tumors in remission was overestimated on MR images because of the extensive surrounding edema and radiation necrosis. MR imaging findings correlated well with those from 48% of brain slices, but resulted in overestimations (24%) or underestimations (28%) of tumor extent in the ten cases of recurrent tumor. The results suggest that information concerning the patient's stage of disease is important in interpreting MR images of gliomas.

Adult↗
PubMed1989

MR angiography with two-dimensional acquisition and three-dimensional display. Work in progress.

Magnetic resonance arteriograms of healthy volunteers and selected patients were produced with a new spoiled gradient-echo pulse sequence based on time-of-flight phenomena. The procedure involves sequential acquisition of many contiguous, thin (1.5-mm) axial two-dimensional sections. These volume data are then submitted to a raytracing projection program, which retrospectively yields multiple arbitrary projection angles rotating through any plane. Venous structures are suppressed with a presaturation slab superior to the current section. The slab location is advanced in concert with advancement of each new section location. The acquisition time varies from 6 to 13 minutes, depending on the number of sections acquired for three-dimensional display. This method obviates the subtraction of image data sets to suppress signals from stationary spins, is more sensitive to slow blood flow than three-dimensional methods of acquisition, and shows special promise for the study of extracranial vascular disease.

Adult↗
PubMed1989

Magnetic resonance imaging and extrapyramidal movement disorders.

High-field strength magnetic resonance imaging is an accurate clinical technique for detecting the relative distribution of ferritin in the brain. In normal adults, iron is found in highest concentrations in the globus pallidus, red nucleus, pars reticulata of the substantia nigra, and dentate nucleus of the cerebellum; its distribution is clearly mapped as signal hypointensity (darkness) on a T2-weighted image due to local-field heterogeneities produced by ferritin. Iron is absent at birth and increases in concentration in the putamen in the elderly. Poorly drug-responsive Parkinson's disease (multiple-system atrophy) is characterized by premature signal hypointensity in the putamen and caudate, while Hallervorden-Spatz disease exhibits abnormal hypointensity in the globus pallidus in children. Dyskinetic disorders often have abnormal signal hyperintensity (whiteness) in the putamen related to gliosis.

Adolescent↗
PubMed1989

Magnetic resonance imaging in pathologically proven Hallervorden-Spatz disease.

We present an 11-year-old girl in whom high field strength MRI performed 2 1/2 years and 6 months before her death showed prominent hypointensity in the globus pallidus and substantia nigra consistent with iron deposition. This finding suggested Hallervorden-Spatz disease, which was confirmed at autopsy.

Basal Ganglia Diseases↗
PubMed1989

Efficacy of MR vs CT in epilepsy.

We studied 59 seizure patients with CT, MR, and EEG to determine the efficacy of each in the detection of an epileptogenic focus. EEG was most sensitive (67%), MR was next (53%), and CT was least sensitive (42%). MR detected an abnormality in five patients (8%) in whom CT was negative. EEG was positive in each of these patients. CT failed to demonstrate any focal lesion not detected by MR. MR and CT detected focal abnormalities in seven patients (12%) who had negative EEGs. Five of the seven patients had brain tumors. Eighteen of the 26 patients who underwent surgery had positive CT and MR; 14 of these patients had tumors. The remaining eight patients who had surgery all had temporal lobectomies for intractable seizures; none had tumors. In the complex partial seizure subgroup of 34 patients, MR was positive in 44%, CT was positive in 29%, and EEG was positive in 80%. We consider MR to be the imaging procedure of choice for the detection of an epileptogenic focus in seizure patients. When indicated, CT may be performed as a second procedure to try to distinguish neoplasm from thrombosed vascular malformations and other lesions.

Brain Neoplasms↗
PubMed1989

Unenhanced and gadolinium-DTPA-enhanced MR imaging in postoperative evaluation in pediatric brain tumors.

Gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) is a chelated paramagnetic contrast agent under clinical trial for use in magnetic resonance (MR) imaging. The increased signal intensity following the intravenous infusion of contrast medium may improve the ability of MR imaging to delineate tumors. The use of this method in 15 pediatric patients with suspected brain-tumor recurrence was analyzed. All 15 patients underwent postoperative Gd-DTPA-enhanced MR imaging, and residual tumor was demonstrated in nine of them. Based on the findings of the enhanced MR studies, four patients had additional surgery, two underwent radiation therapy, and one was given immunotherapy. Continued surveillance was recommended for the remaining eight patients. In all cases the enhanced MR imaging studies were superior to the unenhanced studies in regard to the qualitative and quantitative assessment of the residual tumor. Gadolinium-DTPA-enhanced MR imaging appears to be a safe and effective means of providing an accurate postoperative assessment of residual disease in pediatric brain-tumor patients. It is as effective as contrast-enhanced computerized tomography and has the sensitivity and anatomic resolution provided by MR imaging. The most useful role of this agent was in the postoperative period, in assessing the adequacy of surgical resection. This technique is recommended as the procedure of choice in the postoperative assessment and long-term surveillance of patients with brain tumors.

Adolescent↗
PubMed1988

Cerebral cavernous malformations. Incidence and familial occurrence.

We studied 24 patients with histologically verified cerebral cavernous malformations, reviewing the familial occurrence and presenting signs, symptoms, and radiographic features of the disorder. Eleven patients had no evidence of a heritable trait and had negative family histories. Thirteen patients were members of six unrelated Mexican-American families. Sixty-four first-degree and second-degree relatives were examined, and family pedigrees were established. Most relatives (83 percent) were asymptomatic; 11 percent had seizures. Magnetic resonance imaging was performed in 16 relatives (5 of whom were asymptomatic). Fourteen of the 16 studies revealed cavernous malformations; 11 studies identified multiple lesions. As compared with computerized tomography and angiography, magnetic resonance imaging was far more accurate in detecting cavernous malformations. We conclude that cavernous malformations are more prevalent than previously reported, and that a familial form of the disorder exists that is more common than expected, with a high incidence of multiple lesions and an increased frequency of occurrence among Mexican-American families. Magnetic resonance imaging is the radiographic technique of choice for the identification and follow-up of these lesions.

Cerebral Angiography↗