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Biomedical subjects

O B Boyko

Publications and source records attributed to O B Boyko.

At least 55 records · Page 3Linked to original sources

CT patterns of intracranial hemorrhage complicating thrombolytic therapy for acute myocardial infarction.

Computed tomographic (CT) patterns of intracranial hemorrhage (ICH) were determined in 1,696 patients undergoing thrombolytic therapy for acute myocardial infarction. ICH occurred at 33 sites in 0.77% of patients (n = 13). Thirty-six percent of hemorrhages (n = 12) were intraparenchymal, 33% (n = 11) were subdural, 24% (n = 8) were subarachnoid, and 6% (n = 2) were intraventricular. Eight-four percent (n = 26) of all nonventricular hemorrhages were supratentorial in location. The most common site of ICH was supratentorial and intraparenchymal (10 of 33). In 11 of the 13 patients with ICH, clinical symptoms occurred within 24 hours of the initiation of thrombolytic therapy. A fatal outcome resulted in three of the four patients who had clinical symptoms within 3.5 hours after beginning thrombolytic therapy. The CT findings of multiple intracranial bleeding sites, substantial mass effect with midline shift, and large-volume intraparenchymal hematomas were associated with increased mortality. ICH associated with thrombolytic therapy for acute myocardial infarction has a grave prognosis, with 62% of patients dying during hospitalization.

Aged↗

Hippocampal abnormalities in depression.

A quantitative magnetic resonance imaging study of regional brain T1 spin-lattice relaxation times in 29 normal volunteers and in 20 patients with major depression revealed significantly shortened T1 relaxation times for the hippocampus in depressed patients. These differences were particularly prominent in elderly depressed patients. T1 relaxation times are reflective of the content and macromolecular environment of tissue water protons; shorter hippocampal T1 values may reflect differences in the content or organizational properties of hippocampal water protons. These findings are consistent with several lines of evidence that have implicated a role for the hippocampus in the regulation of mood and in the pathophysiology of the stress response, and they suggest that major depression may be associated with biophysical tissue changes in the aging hippocampus.

Adult↗

Aging of the human corpus callosum: magnetic resonance imaging in normal volunteers.

A brain magnetic resonance imaging (MRI) study of the corpus callosum in 36 normal volunteers, ages 26-79 years, revealed that age was positively correlated with the T1 spin-lattice relaxation time of the corpus callosum and was negatively correlated with the corpus callosum cross-sectional area. T1 relaxation times are sensitive to the content and macromolecular environment of tissue water, and variations in callosal T1 may reflect differences in the content or relaxation properties of callosal water. Such changes also potentially could occur secondary to alterations in the composition of callosal myelin. This study confirms and extends prior morphological studies that have reported age-related dimensional changes in the corpus callosum and, in addition, provides evidence of age-related biophysical tissue differences in the human corpus callosum.

Adult↗

Pituitary size in depression.

Magnetic resonance images centered at the pituitary stalk were used to measure pituitary gland size in 19 patients with major depression compared with that in age- and sex-matched controls. Depressed patients had significantly greater pituitary cross-sectional area (P = 0.0009) and volume (P = 0.007) than the controls. This difference was particularly prominent in elderly depressed patients compared to elderly controls. These results provide the first demonstration of structural alterations in the pituitary gland in major depression.

Adult↗

Magnetic resonance angiography: technique and skull-base applications.

Cerebral angiography has become essential in the evaluation and management of extensive skull-base lesions. However, with a 2.6 percent incidence of neurologic complications and a 0.3 percent incidence of permanent neurologic deficits associated with cerebral angiography, the procedure is not without risk. Recent advances in magnetic resonance angiography (MRA), allow one to visualize the skull-base vasculature without need of intravenous contrast injection or radiation exposure. Our initial experience in visualizing the normal vascular anatomy and pathology at the base of skull with this new imaging modality is presented. Two different MRA techniques were used: (1) thin-slice two-dimensional gradient echo pulse sequence acquisition with three-dimensional projection reconstruction, and (2) two-dimensional phase contrast angiography. The specifics of these techniques and their usefulness in the evaluation of lesions involving the skull base are discussed and demonstrated.

Adult↗

Cerebral white matter disease in late-onset paranoid psychosis.

We examined magnetic resonance (MR) scans of the heads of 8 patients with late onset psychosis and 8 aged controls. Although some patients had mild cognitive impairment, none had depression or a history or examination suggesting focal brain disease. Thus, all patients met DSM-III-R criteria for late-onset schizophrenia. All 8 patients showed significant leukoencephalopathy or vascular pathology on MR imaging, and temporoparietal and occipital lesions were especially prominent. Little such pathology was evident on control scans. We suggest that focal brain disease of vascular origin may be associated with late-onset psychosis, and that MR scanning of such cases may provide important clues to pathogenesis.

Aged↗

A brain magnetic resonance imaging study of pituitary gland morphology in anorexia nervosa and bulimia.

Magnetic resonance imaging (MRI) of the brain was used to examine the morphology and dimensions of the pituitary gland in 18 patients with eating disorders (8 anorectics and 10 bulimics), in comparison with 13 healthy volunteers. None of the 18 patients with anorexia or bulimia had any radiological evidence suggestive of pituitary macroadenoma, cyst, or empty sella. Measurements revealed that the anorectics and bulimics had smaller pituitary gland cross-sectional areas (p less than 0.05) and smaller pituitary gland heights, compared with healthy controls. These preliminary findings in anorectics and bulimics are suggestive of pituitary atrophy secondary to nutritional or endocrine alterations, rather than a primary pituitary pathology.

Adolescent↗

In vivo stereological assessment of caudate volume in man: effect of normal aging.

Using intermediate weighted magnetic resonance imaging (MRI) and a systematic sampling stereological method in 39 normal volunteers aged 24-79 years old, we demonstrated a marked age-associated decline in caudate nuclei volume (r = -0.69, p less than 0.0001). The mean absolute volume of the caudate nuclei in this study (9.4 cm3) was almost identical to that reported in a previous autopsy study and further confirms the validity of this stereological technique for use with MR images. This technique will provide a method for measuring the caudate and other nuclei in vivo, from brain images and, as such, a research tool to correlate age-associated changes in cognitive, sensory and motor function with caudate nucleus volume and other brain regions.

Adult↗

In vivo assessment of pituitary gland volume with magnetic resonance imaging: the effect of age.

We used sagittal and coronal T1 weighted magnetic resonance images, at 1.5 Tesla, to measure the height, width, length, and cross-sectional area and to generate two estimates of pituitary gland volume in 35 normal volunteers aged 26-79 yr (19 females and 16 males). Subjects over 50 yr of age had significantly smaller pituitary gland height (P = 0.03), area (P = 0.04), and volume (P = 0.04) than those under 50 yr (by two-tailed t test). Overall, age was negatively correlated with pituitary volume (V1: r = -0.51; P = 0.003; V2: r = -0.47; P = 0.008), area (r = -0.43; P = 0.009), and height (r = -0.46; P = 0.005), but not with pituitary length or width. There were no statistically significant differences in pituitary size between men and women (by two-tailed t test). These findings suggest that pituitary gland height provides a good single measure for the assessment of pituitary gland size and that age must be controlled for in studies of pituitary gland size.

Adult↗

Sonographic characteristics of small cerebral blood vessels. An in vivo and postmortem study.

The ultrasound appearance of small cerebral blood vessels was investigated with in vivo and postmortem sonography. Linear echoes corresponding in distribution to small branches of major cerebral blood vessels, particularly deep medullary veins, were seen during cranial sonography of living neonates, neonatal postmortem brains, and adult postmortem brains following intravascular injection of a barium sulfate-gelatin suspension. Ease of visualization of the echoes was angle dependent, a phenomenon termed anisotropy. When imaged in cross-section, these reflectors appeared as tiny, closely spaced dots, demonstrating their tubular nature. Additionally, the barium-injected adult postmortem specimens were studied by computed tomography and plain-film radiography, enabling correlation between radiography and sonography. This study demonstrates that small branches of the major intracranial blood vessels can be imaged as linear echoes and closely spaced dots by high-resolution sonography. It is important to recognize the vascular origin of these echoes to avoid the pitfall of misinterpreting them as originating from pathologic processes such as periventricular leukomalacia.

Adult↗

Ectopic immature renal tissue in a lumbosacral lipoma: pathologic and radiologic findings.

Ectopic immature renal tissue was found in a lumbosacral subcutaneous lipoma with intradural extension in a 6-day-old female with spina bifida. No additional neurologic or renal anomalies were found. Ectopic renal tissue is an extremely rare finding. Histopathologic and MRI results from this case are presented and the possible significance of ectopic renal tissue in relation to the origin of extrarenal Wilms' tumors is discussed.

Choristoma↗

MR imaging of osteogenic and Ewing's sarcoma.

Twenty patients with biopsy-proven osteogenic (11 cases) or Ewing's (nine cases) sarcoma were evaluated by MR imaging on a 0.15-T resistive unit to determine the value of MR in the diagnosis and treatment of these two neoplasms and to develop the best protocol for MR imaging. In all 20 cases, MR identified tumor spread into bone marrow, and it was superior to CT in five cases. Extension of tumor into the soft tissues adjacent to bone was shown better by MR than CT in six cases. Improved anatomic information from MR is the result of the ability to image in the axial, coronal, and sagittal planes. Compared with CT, MR identifies cortical disease but has inferior spatial resolution and defines calcium poorly. MR can be used to monitor tumor response to chemotherapy, and the relationship of tumor to adjacent vasculature can be determined without the use of contrast agents. Two pulse sequences are necessary for maximum display of disease, since, in general, tumor involvement of the bone marrow is best assessed on T1-weighted sequences, and tumor involvement of the soft tissue is best seen on T2-weighted sequences. Additional information about bone-marrow involvement, soft-tissue tumor extent, and the relationship of tumor to blood vessels makes MR a valuable adjunct to CT in the evaluation of these neoplasms.

Adolescent↗

Pathological and radiological correlation of subarachnoid hemorrhage in phencyclidine abuse. Case report.

Although hypertension can be associated with phencyclidine (PCP) use, subarachnoid hemorrhage (SAH) is a rare result. The radiological and pathological findings are reported of a patient with acute SAH who had chromatographic evidence of PCP in his blood. The occurrence of SAH in a patient who uses PCP may be caused by a disrupted arterial vessel wall and/or vasospasm due to the pharmacological action of the drug on the cerebral vasculature.

Adolescent↗

Mesenteric vein thrombosis and vascular plasminogen activator.

A 60-year-old woman with livedo reticularis was examined for defective release of vascular plasminogen activator by a newly described chromogenic assay. Her activator level was only 0.007 Committee on Thrombolytic Agents (CTA) units/mL, compared with a mean of 0.19 CTA units/mL for 84 female controls. Subsequently, the patient died as a result of thrombosis of the portal, splenic, hepatic and superior mesenteric veins with small-bowel infarction. The patient's family had a history of deep and superficial vein thrombosis. Her family's medical history was similar to a recently described pedigree, with low levels of releasable plasminogen activator associated with venous thrombosis. We believe that mesenteric vein thrombosis is a serious potential consequence of defective release of vascular plasminogen activator.

Female↗