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Biomedical subjects

O B Boyko

Publications and source records attributed to O B Boyko.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Assessment of posterior fossa structures with midsagittal MRI: the effects of age.

Midsagittal magnetic resonance (MR) images of 36 normal volunteers, ranging in age from 26 to 79 years, were used to evaluate the effects of age on the size of posterior fossa structures (cerebellar vermis, midbrain, pons, medulla and fourth ventricle). Our results demonstrate a highly statistically significant age-related decline in the cross-sectional area of the midbrain (r = -.44, p less than 0.007), a less prominent decline in the area of the anterior cerebellar vermis (r = -.33, p less than 0.05) and striking intercorrelations between the dimensions of the pons, medulla and cerebellar vermis. To the best of our knowledge, this is the first MRI demonstration of midbrain atrophy during aging in normal adults.

Adult↗
PubMedDate not supplied

Subcortical hyperintensities on brain magnetic resonance imaging: a comparison between late age onset and early onset elderly depressed subjects.

Subcortical structural changes have been reported to occur in some elderly subjects with late age onset depression. Given the association between diseases affecting subcortical structures and affective disorders, this suggests that these structural changes may be involved in the etiology of late age onset depression in some patients. With the advent of Brain Magnetic Resonance Imaging (MRI), "in vivo" analysis of these subcortical structures is now possible. The authors report a higher occurrence of caudate (60% vs. 11%) and large deep white matter hyperintensities (60% vs. 11%) in late age onset elderly depressed subjects compared with early onset elderly depressed subjects. These results suggest that late age onset depression may be mediated by caudate and white matter structural changes in some patients.

Aged↗
PubMedDate not supplied

MR diagnosis of herniation of the left ventricle through a pericardial window.

The diagnosis of herniation of the left ventricle through a pericardial window was made using MRI. This is a rare type of herniation because it presented 6 years after a pericardial window was made for pericarditis. Herniation of the heart through congenital, traumatic and post surgical pericardial defects are discussed.

Diagnosis, Differential↗
PubMedDate not supplied

CT and pathologic correlation of Tc-99m medronate splenic uptake in metastatic breast carcinoma.

The CT and autopsy findings in a case of bone tracer uptake by a spleen infiltrated with metastatic breast carcinoma is presented. Calcium could not be demonstrated by either CT or special stains of histologic sections of the spleen. The mechanisms that have been postulated for radiotracer uptake by the spleen are reviewed in relationship to the correlation by this case. In addition, bone tracer uptake did not occur in five other sites of metastatic disease.

Ascites↗
PubMedDate not supplied

Reversible cerebral lesions associated with tiazofurin usage: MR demonstration.

Tiazofurin is an experimental chemotherapeutic agent currently undergoing clinical evaluation. We report our results with magnetic resonance (MR) in demonstrating reversible cerebral abnormalities concurrent with the use of this drug. The abnormalities on MR were correlated with findings on CT as well as with cerebral angiography. The utility of MR in the evaluation of patients receiving this new agent is illustrated.

Antineoplastic Agents↗
PubMedDate not supplied

Dilated Virchow-Robin spaces in cryptococcal meningitis associated with AIDS: CT and MR findings.

We present two patients with AIDS complicated by cryptococcal meningitis who displayed focal hypodense nonenhancing lesions in CT in the basal ganglia with corresponding areas of increased T2 and decreased T1 signal on magnetic resonance (MR). These lesions corresponded precisely to the distribution of the perforating arteries. Review of pathological specimens showed these lesions to be small cystic collections of cryptococcal organisms in the perivascular spaces of the arteries with minimal or no inflammatory reaction. The cryptococcal organisms spread from the basal cisterns through the Virchow-Robin spaces, dilating these spaces, to ultimately propagate in the basal ganglia, internal capsule, thalamus, and brain stem. Such lesions have been described as characteristic for cryptococcosis in the pathology literature before the AIDS epidemic, but the radiological manifestations have not been reported previously. The changes appear characteristic for cryptococcosis, which generally incites no host response in the form of perifocal edema or enhancement. These findings in a young adult, with otherwise normal CT or MR scans, may be the first indication that the patient has AIDS. The T2-weighted image sequences are more sensitive in the detection of these lesions when compared to CT or T1-weighted MR images.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Subdural hematoma in the setting of internal carotid artery occlusion: CT studies.

A 72-year-old woman with previously symptomatic internal carotid artery occlusion subsequently presented with an acute hemispheric deficit. The patient was initially diagnosed as having an ischemic infarction but eventually was shown to have a subacute subdural hematoma with delay in surgical evacuation and a major permanent deficit. We speculate that internal carotid artery occlusion may predispose the patient to greater morbidity from subdural hematoma. Patchy hemispheric infarction may reflect greater vulnerability to extrinsic hemispheric compression in the setting of carotid occlusion. This case illustrates the necessity for vigorous pursuit of the diagnosis of subdural hematoma in patients presumed to have transient ischemic attacks or acute cerebral infarction.

Aged↗
PubMedDate not supplied

Intracerebral extension of nasal dermoid cyst: CT appearance.

We report on a 46-year-old man with a congenital nasal dermoid cyst that extended intracranially to form large bifrontal intraaxial dermoid cysts, which became secondarily infected through a nasal dermal sinus tract. Computed tomography demonstrated bilateral frontal lobe ring enhancing cystic masses containing fat-fluid levels consistent with dermoid cyst abscesses. Axial and coronal CT of the skull base and nose demonstrated a midline bony canal extending from two dimples on the dorsum of the patient's nose to the base of the anterior cranial fossa. The clinical, CT, and surgical findings are reviewed as well as the embryogenesis of congenital nasal dermoid cysts.

Brain Neoplasms↗
PubMedDate not supplied

MRI of temporal lobe pleomorphic xanthoastrocytoma.

Pleomorphic xanthoastrocytomas (PXA) are classically supratentorial, peripherally located, well-circumscribed, partially cystic neoplasms, which can enhance on CT following the administration of intravenous contrast agents. Focal calcification may also be seen. Although the CT appearance has been described, we report the MR findings in two cases of histologically documented temporal lobe PXA. The two well-circumscribed lesions were predominantly cystic and both contained a Gd-DTPA enhancing mural nodule. The latter was isointense with gray matter on T1-weighted images and hyperintense on T2-weighted scans. Minimal surrounding edema was present. Histologically, PXA may be confused with glioblastoma multiforme (GBM) due to the pronounced cellular pleomorphism. Because of their potentially more indolent behavior compared with GBM, it is important to recognize the gross morphologic characteristics of this rare tumor on MR. The MR pattern of a cystic lesion with enhancing mural nodule is characteristic of PXA, but not diagnostic, and other lower grade gliomas such as ganglioglioma and pilocytic astrocytoma need to be considered. The MR and CT appearance of PXA can provide critical information for the pathologist, especially when only a small amount of tissue is obtained for histologic evaluation.

Adult↗
PubMedDate not supplied

Serial FDG-PET studies in the prediction of survival in patients with primary brain tumors.

OBJECTIVE: This study examines the changes in tumor [18F]fluoro-2-deoxyglucose (FDG) uptake on serial FDG-PET studies and the ability of serial FDG-PET studies to predict survival in patients with treated and untreated primary brain tumors. MATERIALS AND METHODS: The study population included 20 patients with primary brain tumors. Changes in FDG uptake over time were visually assessed and correlated with clinical course and survival. RESULTS: Although little change in FDG uptake was noted for individual patients, high average FDG uptake (greater than or equal to gray matter) on serial studies was associated with shorter survival. Patients with persistently low FDG uptake (less than gray matter) survived significantly longer than patients with persistently high FDG uptake (p = 0.007). CONCLUSION: Serial evaluation of metabolic activity with PET may provide more accurate prognostic information than a single FDG uptake determination in patients with primary brain tumors.

Adult↗
PubMedDate not supplied

Non-heme mechanisms for T1 shortening: pathologic, CT, and MR elucidation.

PURPOSE: To further elucidate the nonparamagnetic effects of T1-relaxation mechanisms in MR imaging. PATIENTS AND METHODS: In 12 patients with lesions having hyperintense signal on T1-weighted spin-echo MR, findings were correlated with autopsy/surgical biopsy in seven cases and/or noncontrast CT scans in 10 cases. RESULTS: Eight of the 10 CT scans demonstrated hyperattenuation in the lesions, indicating mineralization, which correlated with the areas of hyperintense signal on MR. Histologic characterization of the mineralization was accomplished in three cases using four stains; hematoxylineosin, alizarin red S, von Kassa stains for calcium and Perls' iron. The areas of mineralization were homogeneously strongly positive with the calcium stains and only focally weakly positive with the Perls' iron stain. The mineralization was further characterized in all three cases as containing calcium and phosphorus using energy-dispersive x-ray analysis. Four of the 12 cases had either no correlating CT scans (two cases) or the CT showed no hyperattenuating properties to the lesions (two cases). In all four of these cases, microscopic examination showed that the gyriform configuration of the cortical hyperintense signal on T1-weighted images correlated with linear zones of nonhemorrhagic laminar necrosis (cerebral infarction). No mineralization, except for an occasional ferruginated neuron, could be demonstrated with the four histologic stains. Specimen MR imaging of formalin-fixed brain sections in one case demonstrated in vitro the gyriform hyperintense signal seen in vivo. CONCLUSION: Our studies describe and pathologically characterize two associations with T1 shortening in neuroimaging unrelated to the presence of heme: 1) calcification and 2) laminar necrosis in cerebral infarction.

Brain↗
PubMedDate not supplied

Morphometric changes of the human midbrain with normal aging: MR and stereologic findings.

PURPOSE: To determine the effects of age on estimated midbrain volume. PATIENTS AND METHODS: T2-weighted MR imaging and an unbiased stereologic method were used in 75 volunteers; the subjects ranged in age from 21 to 82 years and were without any significant neurologic or psychiatric disorders. RESULTS: Age was negatively correlated with estimated midbrain volume (R = -.39, P less than .0005), with the anteroposterior diameter through the substantia nigra (R = -.33, P less than .004) and with the interpeduncular distance (R = -.24, P less than .04). The linear measurements for the right and left side were almost identical. These findings are consistent with prior reports of nigrostriatal degeneration with increasing age. Furthermore, they suggest a close symmetry of age-related changes between the right and left side in normal subjects. CONCLUSIONS: Volumetric and linear measurements of midbrain morphology with MR may prove useful in the investigation of neurologic disorders such as Parkinson disease.

Adult↗
PubMedDate not supplied

Hamartomas of the tuber cinereum: CT, MR, and pathologic findings.

The neuroimaging studies, clinical evaluations, and surgical and pathologic findings in five children with biopsy-proved hamartomas of the tuber cinereum were reviewed. Surgical and/or MR findings showed that patients with precocious puberty had pedunculated lesions while those with seizures had tumors that were sessile with respect to the hypothalamus. The radiologic studies included six MR examinations in four patients and CT studies in all five patients. Three children presented with precocious puberty and two with seizures, one of which was a gelastic (spasmodic or hysteric laughter) type of epilepsy. MR studies were obtained both before and after surgery in two patients, only preoperatively in a third patient, and only postoperatively in the fourth child. MR was superior to CT in displaying the exact size and anatomic location of the hamartomas in all cases. The mass was isointense with gray matter on sagittal and coronal T1-weighted images, which best displayed the relationship of the hamartoma to the third ventricle, infundibulum, and mammillary bodies. Intermediate- or T2-weighted images showed signal characteristics of the hamartoma to be isointense (one case) or hyperintense (two cases) relative to gray matter. The difference in T2 signal intensity did not correlate with any obvious differences in histopathology. CT showed attenuation isodense with gray matter, and no calcium. There was no enhancement on CT. There was no enhancement on MR in the one case in which contrast medium was administered. Preservation of the posterior pituitary bright spot was noted on all pre- and postoperative T1-weighted MR scans.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMedDate not supplied

In vivo stereological assessment of human cerebellar volume: effects of gender and age.

Intermediate T2-weighted MR images and a systematic sampling stereological method were used in 37 normal volunteers, 24 to 79 years old, to assess the effects of age and sex on cerebellar volume. Female subjects (n = 21) had significantly smaller cerebellar volumes compared with males (n = 16) of similar age (t = -3.9, p less than .0008, two-tail t test). Using straight-line, univariate regression, we determined that age was not a significant predictor of cerebellar volume (R2 = 0.07, t = -1.66, p = 0.11), whereas gender did appear to account for a significant amount of variability in cerebellar volume (R2 = 0.33, t = -4.13, p = .0002). The mean absolute cerebellar volume in this study was 112 ml (SD +/- 16) for all subjects, 104 ml (SD +/- 10) for females, and 122 ml (SD +/- 16) for males. This study demonstrates the feasibility of using MR images along with a systematic stereological method to assess in vivo human cerebellar volume, thereby providing a research tool to correlate cerebellar morphology with cognitive and neuromotor function.

Adult↗