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Biomedical subjects

G Sze

Publications and source records attributed to G Sze.

At least 73 records · Page 4Linked to original sources
PubMed1988

Malignant extradural spinal tumors: MR imaging with Gd-DTPA.

Magnetic resonance (MR) imaging with gadolinium diethylenetriaminepentaacetic acid (DTPA) was performed in 12 patients with neoplasia of the spine and epidural space. Postcontrast images were compared with precontrast images. Gd-DTPA MR images did not improve the detection of tumors affecting the epidural space of the spine. In fact, many lesions were isointense when compared with the intensity of the surrounding bone marrow and were difficult to see. Because of this, contrast material-enhanced images were not sufficient; however, when they were combined with precontrast images, the use of Gd-DTPA improved the delineation and characterization of certain lesions. Gd-DTPA MR images were helpful in differentiating disk herniation from epidural tumors, indicating regions of more active tumor for biopsy, outlining areas of spinal cord compression, and demonstrating tumor response to therapy. Therefore, while it may be unlikely that Gd-DTPA will be used routinely in every case of suspected neoplasia of the epidural space, contrast-enhanced images will undoubtedly have an adjunctive role in certain clinical applications.

Adult↗
PubMed1988

Intraparenchymal brain metastases: MR imaging versus contrast-enhanced CT.

Prospective and retrospective studies of 75 patients were performed to assess the sensitivities of magnetic resonance (MR) imaging and computed tomography (CT) in the evaluation of suspected intraparenchymal brain metastases. The findings on MR images were equivalent to those on CT scans in 49 of the 75 patients; the remaining findings were discordant in 26 patients, and neither MR imaging nor CT was consistently superior. MR imaging demonstrated more metastases in nine of these 26 patients. However, contrast material-enhanced CT scans were superior in lesion depiction in eight of the 26 patients. Large enhanced lesions that were nearly isointense on MR images were seen well on CT scans. In several cases in which results were discordant, gadolinium-diethylenetriaminepentaacetic acid (DTPA)-enhanced MR images were obtained, and this agent behaved similarly to iodinated contrast agents. If indicated clinically, such as before surgery for a single metastasis, the authors perform both MR imaging and contrast-enhanced CT. Gd-DTPA-enhanced MR imaging may prove to be the method of choice for depiction of intraparenchymal metastases.

Adolescent↗
PubMed1988

Gadolinium-DTPA in the evaluation of intradural extramedullary spinal disease.

Gadolinium-DTPA was used in MR imaging of the spine to determine the ability of a contrast agent to increase the detection and characterization of disease in the intradural extramedullary space. Although MR imaging, especially with recent technological improvements, has been shown to be at least competitive with, and often superior to, myelography and postmyelography CT in the study of intramedullary and extradural disease, its use in the assessment of intradural extramedullary disease has been questioned. We selected 12 patients with intradural extramedullary disease as demonstrated by positive CSF cytology and/or myelographic findings and performed MR examinations on them before and after administering gadolinium-DTPA (0.1 mmol/kg). Gadolinium-DTPA was extremely effective in depicting intradural extramedullary disease of the spine. Small nodules of 3 mm, virtually invisible on noncontrast MR scans, enhanced strongly and were easily detected. In addition, leptomeningeal spread of tumor along nerve roots was also visualized, sometimes more readily than by myelography and postmyelography CT. The remarkable sensitivity of gadolinium-DTPA to intradural extramedullary disease assures its role in future MR examinations of the spine.

Adult↗
PubMed1988

MR of cranial and spinal meningeal carcinomatosis: comparison with CT and myelography.

Thirty-nine patients with histologically proved primary neoplasms, focal neurologic deficits, and positive CSF cytology were evaluated by enhanced cranial CT and MR, or complete myelography and MR of the spine. Intracranial abnormalities were noted on CT in 56% of cases and included abnormal enhancement of subarachnoid space and ventricular walls, ventricular dilatation, obliteration of cortical sulci, and enhancing nodules within the subarachnoid cisterns and lumen of the lateral ventricles. Although the degree of ventricular enlargement and intraventricular tumor deposits were equally well seen on CT and MR, involvement of ventricular walls, tentorium, subarachnoid cisterns, or subarachnoid space interpreted as abnormal enhancement on CT was not readily appreciated on routine T1- and T2-weighted spin-echo sequences. Forty-four percent of CT and 65% of MR studies were interpreted as normal. There was high correlation of myelographic findings with clinical diagnosis, and no false-negative myelograms. Nodular filling defects within the subarachnoid space, thickening and crowding of roots of the cauda equina, irregularity of individual roots, and scalloping of the subarachnoid membranes were demonstrated. MR was rather insensitive in detecting these changes, revealing a definite abnormality of the subarachnoid space in 27% of patients with positive myelograms. False-negative interpretation of MR of the spine was made in 44% of cases.

Brain Neoplasms↗
PubMed1988

Intramedullary disease of the spine: diagnosis using gadolinium-DTPA-enhanced MR imaging.

Twenty-six patients with suspected lesions of the spinal cord were studied before and after administration of gadolinium-DTPA to assess whether contrast enhancement was useful in the MR evaluation of intramedullary disease. Nine patients had primary tumors, six had benign syringes, three had multiple sclerosis with cord involvement, three had thrombosed vascular malformations, three had probable intramedullary metastasis, and two were normal. Although all lesions were detected on noncontrast MR scans, gadolinium-DTPA was of great help in their delineation and characterization. Specifically, contrast material may be able (1) to localize tumor nidus and separate it from edema, in cases of hemangioblastomas and metastases; (2) to suggest regions of more active tumors, in cases of glioma, for surgical biopsy or removal; (3) to differentiate benign or reactive processes from neoplastic lesions, such as reactive cyst from tumor cyst or hematoma due to thrombosed malformation from tumor hemorrhage; and (4) possibly to differentiate active from inactive lesions, for example, in multiple sclerosis. Because of these advantages, gadolinium-DTPA probably will often be used routinely when intramedullary lesions are detected on noncontrast MR scans.

Adult↗
PubMed1988

The magnetic resonance imaging of infections and inflammatory diseases.

The MR features of inflammatory lesions of the central nervous system are reviewed in this article, and the sensitivity and specificity of MR and CT in the detection of these lesions are compared. The advent of CT dramatically improved the morbidity and mortality of inflammatory disease by facilitating earlier and more accurate diagnosis which, in turn, produced more timely medical and surgical intervention. The efficacy of MR in the evaluation of inflammatory lesions must, therefore, be compared to CT in order to accurately asses its role.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Gadolinium-DTPA in spinal disease.

The use of paramagnetic contrast agents, in particular, gadolinium-DTPA, holds great promise for the MR evaluation of the spine. However, because of the lack of a previous model for intravenous contrast enhancement in the spine and because of some peculiarities of enhancement of spinal lesions, close attention must be paid to the appropriate uses of contrast in MR of the spine. Gadolinium-DTPA appears to be extremely useful in intradural extramedullary disease and intramedullary disease, but its use in extradural disease may best be restricted to certain specific clinical situations.

Adult↗
PubMed1987

Hemorrhagic neoplasms: MR mimics of occult vascular malformations.

The MR scans of 24 patients who had findings previously reported to be characteristic of occult cerebral vascular malformations were reviewed to demonstrate that such findings may also occur in primary or secondary neoplasms. Eighteen of the 24 patients were found to have hemorrhagic neoplasms. Additional criteria, such as multiplicity of lesions and the presence of edema, were of some help in differentiating between occult vascular malformation and hemorrhagic neoplasm. In certain cases, CT was necessary to provide further information, such as the presence of calcification; however, an absolute and accurate diagnosis was impossible in several cases. The striking similarity on MR between cryptic vascular malformation and some hemorrhagic neoplasms is most likely due to the unifying mechanisms that underlie the evolution of extravascular intracerebral blood. Although the preponderance of neoplastic etiologies in our series may be partly due to the strong bias in our sample population toward patients with tumors, it seems clear that when an MR scan discloses findings "typical" of an occult vascular malformation, consideration must also be given to the generally more serious possibility of underlying neoplasm.

Adolescent↗
PubMed1986

Pseudotumor of the craniovertebral junction associated with chronic subluxation: MR imaging studies.

Masses at the craniovertebral junction generally have serious prognostic implications. However, the authors studied three patients who had chronic atlantoaxial subluxation from either degenerative disease or congenital dysplasia of the dens and who also had benign fibrous masses in this region, confirmed at surgery. The association of masses of the craniovertebral junction with chronic atlantoaxial subluxation raises the possibility that the underlying cause of the masses is chronic mechanical irritation. All patients were imaged with metrizamide myelography and adjunctive computed tomography (CT), then by magnetic resonance (MR) imaging. MR images were not only superior to myelograms and CT scans in delineating the exact extent of the lesions, they also indicated the benign, fibrous nature of the masses.

Adult↗
PubMed1986

Pituitary adenomas: high-resolution MR imaging at 1.5 T.

The magnetic resonance (MR) images of 28 patients with surgically confirmed pituitary adenomas were retrospectively evaluated. The examinations were performed on a 1.5-T superconducting MR system using a multisection spin-echo technique with 3-mm-thick sections and a 256 X 256 matrix. T1- and T2-weighted images were obtained in sagittal and coronal planes. The MR findings were correlated with detailed operative reports and diagrams. There were 11 microadenomas and 17 macroadenomas. Ten of the microadenomas and all of the macroadenomas were accurately localized and their extent delineated, particularly on T1-weighted coronal sections. Adenomas typically appeared hypointense on T1-weighted coronal sections. The appearance on T2-weighted images was variable, and generally the lesions were less well seen. Involvement of parasellar structures, particularly the optic chiasm and cavernous sinuses, was accurately depicted. Cyst formation and hemorrhage could be characterized in some instances. In general, there was excellent correlation between MR imaging and operative findings.

Adenoma↗
PubMed1986

Foci of MRI signal (pseudo lesions) anterior to the frontal horns: histologic correlations of a normal finding.

Review of all normal magnetic resonance (MR) scans performed over a 12-month period consistently revealed punctate areas of high signal intensity on T2-weighted images in the white matter just anterior and lateral to both frontal horns. Normal anatomic specimens were examined with attention to specific characteristics of this region. Three unique features typify the brain tissues that correspond to the foci of high signal. First, this region of the brain is notable for its loose network of axons with low myelin content. Second, pathologic scrutiny revealed an entity called "ependymitis granularis," which represents patchy loss of the ependyma in the frontal horns with astrocytic gliosis. Third, flow of interstitial fluid within this region of the brain tends to converge at the dorsal-lateral angle of the frontal horns. All these factors contribute to increased water content locally, which results in foci of high signal intensity anterior to the frontal horns in all normal MR scans.

Adolescent↗
PubMed1986

Gadolinium-DTPA in the magnetic resonance evaluation of the postoperative patient. Work in progress.

The application of gadolinium-DTPA to magnetic resonance scanning has been demonstrated to have considerable potential. Because the evaluation of the post-operative patient is particularly difficult for magnetic resonance due to the non-specific appearance of surgical trauma and edema, we attempted to formulate some preliminary impressions regarding the use of gadolinium-DTPA in this setting based on our experience with 15 patients studied at varying intervals following surgery, from 2 days to 8 years. Specifically, the time course and appearance of normal post-surgical enhancement was found to exhibit certain patterns. Recognition of these patterns may allow differentiation from pathology and may result in gadolinium-DTPA adding useful information in evaluating these patients.

Adult↗
PubMedDate not supplied

Gadolinium-enhanced MR in spinal infection.

The purpose of this study was to determine what advantages the use of paramagnetic contrast material might have in evaluating patients clinically suspected of having spinal infection. To determine this we prospectively examined with noncontrast and contrast magnetic resonance (MR) 33 such patients and correlated the MR diagnoses with clinical and pathologic data. Our results showed the following advantages of gadolinium-enhanced MR: it (a) provided excellent anatomical delineation of all epidural abscesses, routinely differentiating them from the adjacent compressed thecal sac even when this was not possible by noncontrast MR; (b) increased observer confidence in the diagnosis of disk space infection and osteomyelitis in patients with equivocal noncontrast MR; (c) localized those portions of paraspinal masses most likely to yield a positive percutaneous biopsy; and (d) identified active infections from those that had responded adequately to antibiotic therapy. We conclude that contrast MR is a valuable adjunct to noncontrast MR when diagnosis, anatomical clarity, and/or lesion activity requires further elucidation.

Abscess↗
PubMedDate not supplied

Spinal cord MRI in adult polyglucosan body disease.

MRI appearance of adult polyglucosan body disease is described. A 67-year-old man presenting with a chronic progressive degenerative neurologic disorder was found to have marked atrophy of the entire cord, without signal abnormalities on long TR images. Autopsy revealed atrophy of the cord, diffuse gliosis, and numerous corpora amylacea.

Aged↗