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Biomedical subjects

M A Weinstein

Publications and source records attributed to M A Weinstein.

At least 37 records · Page 2Linked to original sources
PubMed1988

Association of heterotopic gray matter with seizures: MR imaging. Work in progress.

Heterotopic gray matter, which previously had been associated with severe congenital malformations of the brain and developmental delay, was found without these associated conditions. The authors found ten cases of heterotopic gray matter on magnetic resonance (MR) images. The lesions had a signal intensity that was isointense compared with that of gray matter on T1, spin-density, and T2-weighted images. Nine of the ten cases were associated with a seizure disorder. The tenth case, discovered during a workup for metastatic lung disease, was confirmed with pathologic studies. Heterotopic gray matter is the presence of cortical neurons in an abnormal location, which may be periventricular (nodular) or within the white matter (laminar). A knowledge of heterotopic gray matter and its association with seizures may prevent the misinterpretation of findings on MR images.

Adolescent↗
PubMed1988

ENG-MRI correlates in cerebellar oculomotor dysfunction.

This study correlates ENG and MRI findings in six patients with cerebellar eye movements. For each subject, both tests independently support the presence of a cerebellar tract abnormality. In two patients, MRI studies confirmed the site of cerebellar dysfunction previously demonstrated by ENG. Although the number of patients is small, the strong correlation (100%) indicates that ENG remains a sensitive method for detection and localization of the origin of cerebellar eye movements. The physiologic information provided by ENG is supported anatomically by MRI. The cerebellar eye movement abnormalities are briefly reviewed.

Adolescent↗
PubMed1987

Primary anorectal lymphoma. A new manifestation of the acquired immune deficiency syndrome (AIDS).

Non-Hodgkin's lymphomas with particular clinicopathologic features occur with a high incidence in homosexual men affected by AIDS. More frequently than in the general population, these lymphomas have an extranodal location including the gastrointestinal tract. We have recently observed four cases of AIDS-associated lymphomas whose primary location is in the lower rectum and anus. The patients were 27 to 44 years of age, had greatly depressed helper-suppressor T-cell ratios, and antibodies to human immunodeficiency virus (HIV). All four presented with anorectal symptoms and originally had surgery for anorectal fistulas or tumor masses. When staged, three patients had no other organ involvement, the fourth only had lymphoma in an axillary lymph node, and all four had large tumor masses confined within the rectum. In terms of histology, the lymphomas were of undifferentiated or of large cell type and of B-cell phenotype. Lymphomas with primary or major location in the rectum are a rare occurrence in the general population, and until recently, are rare even among the lymphomas associated with the immune deficiency syndrome. At the Lenox Hill Hospital in New York City, no rectal lymphoma among the 58 cases of AIDS-related lymphoma diagnosed during the past 4 years was recorded until 10 months ago. The recognition of the new feature in presentation, a neoplasm associated with AIDS, is obviously important for its early diagnosis and treatment. Its unusual occurrence at the suspected portal of entry of the HIV infection is of interest because it may provide new clues to the association between AIDS and neoplasia.

Acquired Immunodeficiency Syndrome↗
PubMed1987

The preoperative venogram in planning extended craniectomies.

A technique of extended craniectomy sometimes allows removal of large central or transtentorial mass lesions at a single operative sitting because it affords better exposure and control of normal structures. While seeking to avoid multiple craniotomies, this method requires permanent ligation of the transverse venous sinus. Unless there is adequate collateral venous drainage from the ipsilateral hemisphere, the patient is at risk for venous infarction in the post-craniectomy period. The purpose of this study is to propose a method of establishing the presence of collateral venous drainage preoperatively. Each carotid artery is injected with the head in a neutral position and with the head turned to the side ipsilateral to the carotid artery injection in an attempt to divert the venous flow. Fifty patients were examined using this method; seven were being evaluated for possible craniectomies. The technique identified nine patients with potential venous collaterals (20%). They would otherwise have been considered nonoperable: two of the six patients eventually operated upon (33%) fell into this category. In general, the operative procedure may be safe more often on the left than the right (45%) vs (20%). Particular attention must be given to the pattern of venous drainage from the posterior temporal lobe to avoid isolation of the venous drainage from this area.

Adult↗
PubMed1986

Magnetic resonance imaging (1.5 tesla) in patients with intractable focal seizures.

Magnetic resonance (MR) (1.5 tesla) studies were performed in ten patients with temporal lobe epilepsy and two with temporofrontal epilepsy. Two patients with temporal lobe epilepsy and one with temporofrontal epilepsy exhibited areas of increased signal intensity on T2-weighted images in the mesiobasal portion of the temporal lobe shown by electroencephalography to be the epileptogenic focus; no analogous abnormalities had been found in these patients on computed tomographic scans. Pathologic studies have not revealed a specific ultrastructural correlate for the MR findings in this group of patients. We found MR to be a useful, noninvasive diagnostic adjunct in the presurgical assessment of some patients with temporal lobe epilepsy. Where abnormalities were found, they corresponded with the epileptogenic focus as defined by electroencephalography.

Adult↗
PubMed1985

Magnetic resonance of brain tumors: considerations of imaging contrast on the basis of relaxation measurements.

Proton spin-lattice and spin-spin relaxation times have been measured in surgically-removed normal CNS tissues and a variety of tumors of the brain. All measurements were made at 20 MHz and 37 degrees C. Between grey and white matter from autopsy human or canine specimens significant differences in T1 or T2 were observed, with greater differences seen in T1. Such discrimination was reduced in samples obtained from live brain-tumor patients due to lengthening in T1 and T2 of white matter near tumorous lesions. Edematous white matter showed T1 and T2 values higher than those of autopsy disease-free white matter. Compared to normal CNS tissues, most brain tumors examined in this study demonstrated elevated T1 and T2 values. Exceptions, however, did exist. No definitive correlation was indicated on a T1 or T2 basis which allowed a distinction to be made between benign and malignant states. Furthermore, considerable variation in relaxation times occurred from tumor to tumor of the same type, suggesting that within a tumor type there are important differences in physiology, biology, and/or pathologic state. Such variation caused partial overlap in relaxation times among certain tumor types and hence may limit the capability of magnetic resonance imaging (MR) alone for the diagnosis of specific disease. Nonetheless, this study predicts that on the basis of T1 or T2 differences most brain tumors are readily detectable by MR via saturation recovery or inversion recovery with appropriate selections of pulse-spacing parameters. In general, tumors can be discriminated against white matter better than grey matter and contrast between glioma and grey matter is usually superior to that between meningioma and grey matter. This work did not consider tissue-associated proton density which should be addressed together with T1 and T2 for a complete treatment of MR contrast.

Adenoma↗
PubMed1985

The intranuclear cleft of the intervertebral disk: magnetic resonance imaging.

Three cadaver spines, 40 patients who were symptomatic for lumbar disk disease, and ten healthy subjects were examined by MR. T2 weighted spin echo images were used to evaluate the character of an intranuclear cleft. This cleft appears identical to annular tissue both on T2 weighted images and histologically. A 120 msec TE, 3 sec TR image was used to delimit the normal nucleus pulposus from the annulus. The incidence and age distribution of the cleft were calculated. An intranuclear cleft was present in all normal disks in both control and symptomatic subjects who were 30 years of age and older. If present in one disk, it was also present in 94% of the other disks in the same subject. This cleft represents a normal anatomic structure and appears to be a constant feature in subjects 30 years of age or older. Its absence, in the presence of an increased signal intensity within the disk, suggests a pathological process with a long T2 value, such as inflammation.

Adolescent↗
PubMed1985

Vertebral osteomyelitis: assessment using MR.

Thirty-seven patients who were clinically suspected of having vertebral osteomyelitis were prospectively evaluated with magnetic resonance (MR), radiography, and radionuclide studies. These findings were correlated with the final clinical, microbiologic, or histologic diagnoses. Based on the results of these latter studies, 23 patients were believed to have osteomyelitis. MR examinations consisted of at least a sagittal image (TE = 30 msec, TR = 0.5 sec) and an image obtained at TE = 120 msec, TR = 2-3 sec. All patients underwent radiographic and MR examinations, 36 underwent technetium 99m-HDP bone scanning, and 20 patients underwent gallium 67 scanning. Nineteen patients underwent both bone and gallium scanning. The imaging studies were reviewed independently by investigators blinded to the final diagnoses. MR had a sensitivity of 96%, specificity of 92%, and accuracy of 94%. Combined gallium and bone scan studies (19 cases) had a sensitivity of 90%, specificity of 100%, and accuracy of 94%. Bone scans alone had a sensitivity of 90%, specificity of 78%, and accuracy of 86%. Plain radiographs had a sensitivity of 82%, specificity of 57%, and accuracy of 73%. The MR appearance of vertebral osteomyelitis in this study was characteristic, and MR was as accurate and sensitive as radionuclide scanning in the detection of osteomyelitis.

Adult↗
PubMed1985

Magnetic resonance with marked T2-weighted images: improved demonstration of brain lesions, tumor, and edema.

The object of this study was to determine the sensitivity of magnetic resonance (MR) for imaging intracranial lesions with heavily T2-weighted images compared with that of computed tomographic (CT) and T1-weighted images. Fifty-five patients with known intracranial pathology consisting of primary neurogenic tumors, brain infarcts, demyelinating disease, and metastases were studied by MR and CT. Patients were studied with either 0.6 or 1.5 T systems with T1- and T2-weighted radiofrequency pulse sequences. The heavily T2-weighted images were found to be superior to the T1-weighted images in terms of sensitivity, with 168 lesions found versus 86 by CT and 104 by T1-weighted imaging.

Brain Edema↗
PubMed1984

Magnetic resonance. Principles and applications.

Magnetic resonance is a unique, noninvasive imaging modality which allows direct, multiplanar imaging and the possibility of obtaining biochemical information in vivo. Presently, MR appears most applicable to the evaluation of central nervous system abnormalities. The high sensitivity of MR in the evaluation of intracranial pathology suggests that it may eventually replace CT for many suspected diseases, if future investigations are able to improve its specificity. As previously noted, MR may be more diagnostic than other radiologic studies in the evaluation of suspected Chiari malformation, syringomyelia, congenital abnormalities, tumors of the spinal axis, and disc space infection. In the chest, MR appears to be more accurate than CT in the determination of the extent of mediastinal tumor, but at present cannot replace CT because of the lack of experience in imaging parenchymal nodules and benign diseases. MR of the breast is promising, but the size of the lesion may prove to be a limiting factor with magnetic field strengths commonly being utilized. There are inherent difficulties in the evaluation of cardiac disease with MR, but it offers a noninvasive method of investigating congenital heart disease and may provide valuable information in suspected myocardial ischemia and altered cardiac function. MR provides a new method of evaluating the vascular system, both in terms of providing anatomic information on large and medium-sized vessels and flow analysis. In the abdomen, MR appears to be most sensitive in the evaluation of suspected hepatic masses, but as with the brain, greater specificity will be needed to replace CT. At the present time, MR offers no distinct advantage over conventional imaging modalities in the evaluation of pancreatic disease, it maybe more accurate than CT in the staging of renal cell carcinoma. Larger studies are needed to determine the role of MR in the investigation of retroperitoneal adenopathy and adrenal abnormalities. In the pelvis, MR offers the hope of earlier diagnosis of prostatic carcinoma and may replace CT for staging of prostatic carcinoma and transitional cell carcinoma of the bladder. Limited MR experience with benign disease of the female pelvis suggests that it is currently more accurately evaluated with ultrasound. MR appears to be highly sensitive and specific for the diagnosis of avascular necrosis and may provide an early clue in suspected osteomyelitis. Finally, in vivo MR spectroscopy may provide unique metabolic information that was unobtainable prior to the advent of magnetic resonance, if this proves to be technically feasible.

Bone Diseases↗
PubMed1984

Magnetic resonance imaging of intervertebral disk disease. Clinical and pulse sequence considerations.

Sixty-five patients were examined with magnetic resonance imaging (MR) to determine what combination of operator-selectable controls would result in a thorough examination of the intervertebral disks. There were 20 normal subjects, 8 with degenerative lumbar disk disease, 27 with both degeneration and herniation, 5 with stenosis of the spinal canal, and 5 with disk space infection. T2 was significantly longer in the normal nucleus pulposus than in the degenerated disk. Based on plots of in vivo signal intensity vs. repetition time (TR) for various echo times (TE), a sagittal 30-msec. TE and a 0.25-sec. TR were used for anatomical delineation and rapid localization, while sagittal and/or axial 120-msec. TE/3-sec. TR images were used to evaluate the cerebrospinal fluid and disk. Comparison with radiographs, high-resolution CT scans, and myelograms showed that MR was the most sensitive for identification of degeneration and disk space infection, separating the normal nucleus pulposus from the annulus and degenerated disk. Herniation, stenosis of the canal, and scarring can be identified as accurately with MR as with CT or myelography.

Adult↗
PubMed1984

Nuclear magnetic resonance of the spine: clinical potential and limitation.

Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluated. It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin-echo technique with appropriate T1 and T2-weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography.

Arteriovenous Malformations↗
PubMed1984

Complications of Crohn's disease predisposing to dysplasia and cancer of the intestinal tract: considerations of a surveillance program.

Carcinomas of the ileum and colon in patients with Crohn's disease are being reported with such increasing frequency as to raise the question of a surveillance program to find dysplasia or the carcinoma itself at the earliest possible time. Accordingly, we consider the overall risk with emphasis on specific manifestations of Crohn's disease which predispose to malignancy so that the surveillance might be given special direction. Two more cases of carcinoma in Crohn's disease are reported, one in association with a long-standing fistula, the other with synchronous, metachronous, and multifocal lesions, and both with dysplasia.

Adenocarcinoma↗