Biomedical subjects

G A Press

Publications and source records attributed to G A Press.

At least 37 records · Page 2Linked to original sources

PubMed1989

Reduced cerebellar hemisphere size and its relationship to vermal hypoplasia in autism.

Cerebellar hemisphere size was calculated in 10 autistic and 8 normal control subjects by summing the cross-sectional areas of cerebellar hemisphere tissue measured on paramidline sagittal magnetic resonance images. The areas of two cerebellar vermal regions (lobules I through V and lobules VI through VII) were also measured using the midsagittal image. Our cumulative slice area measure of cerebellar hemisphere size was significantly smaller in the autistic subjects than in the control group. The cumulative slice area correlated positively with the area of vermal lobules VI through VII only in the autistic subjects. Our results indicated that the decreased size of the cerebellar hemispheres and vermal lobules VI through VII was associated with autism.

Autistic Disorder↗

PubMed1989

The ferret as an animal model in cerebrovascular research.

Clinical and pathologic observations have suggested analogies between the developing nervous system of ferrets (Mustela putorius furo) and those of more traditional animal models employed in stroke research. Experimental work has demonstrated advantages of the ferret as a model of visual development. We performed in vivo cerebral angiography and postmortem neurovascular dissection of latex-injected specimens of adult ferrets. The great vessels include a cervical arterial trunk that gives rise to both carotid arteries. The anatomy of the cranial arteries is similar to that of rabbits. No carotid rete mirabile is present. There are no intracranial anastomoses between the external and internal carotid systems. We present in vivo cerebral angiograms with pathologic correlation that demonstrate that ferrets may provide the same anatomic advantages as a rabbit model for the experimental study of cerebrovascular disease, with the additional advantage of a long extracranial cervical segment of the carotid artery, affording easier access to the intracranial vasculature.

Animals↗

PubMed1989

Tissue plasminogen activator-mediated thrombolysis of cerebral emboli and its effect on hemorrhagic infarction in rabbits.

Tissue plasminogen activator (tPA) dissolves intravascular thrombus and restores blood flow after thromboembolic vascular occlusion. The utility of this agent for treatment of stroke in humans may be limited by post-reperfusion hemorrhagic complications. We studied tPA-mediated thrombolysis in an animal model of cerebrovascular occlusion in order to determine what factors, if any, predispose tPA-treated animals to suffer hemorrhage. Small blood clot emboli were injected into the internal carotid arteries of rabbits. Angiograms confirmed occlusion of the middle cerebral artery or internal carotid artery in 100% of subjects. tPA or saline was administered as a 30-minute infusion at various times after embolization. Hemorrhage rates were similar in all groups regardless of treatment. tPA increased the prothrombin time and the thrombin time but not the partial thromboplastin time. There was no correlation between these changes in blood coagulation and the finding of cerebral hemorrhage. We observed a significant association between stroke severity and cerebral hemorrhage. We conclude that tPA treatment successfully causes thrombolysis of cerebral emboli without causing an increase in the incidence of cerebral hemorrhage in rabbits.

Animals↗

PubMed1989

Diagnosis and treatment of an odontoid fracture in a patient with polyostotic fibrous dysplasia: case report.

Fibrous dysplasia of the cervical spine is rare. No prior reports have discussed odontoid fractures in the setting of fibrous dysplasia. We describe a 26-year-old man who suffered a traumatic odontoid fracture in an area of preexisting fibrous dysplasia. The patient was treated conservatively in a sterno-occipito-mandibular immobilizer brace with a good result. A review of fibrous dysplasia is presented. Alternative methods of diagnosis and treatment options in our patient are discussed.

Adult↗

PubMed1989

The cerebellum in sagittal plane--anatomic-MR correlation: 1. The vermis.

Correlation of thin (5-mm) sagittal high-field (1.5-T) MR images of three brain specimens and 11 normal volunteers with microtome sections of the human cerebellar vermis and hemispheres demonstrates that proton-density-weighted (long TR/short TE) and T2-weighted (long TR/long TE) spin-echo pulse sequences provide the greatest contrast between gray and white matter. These images also can display (1) the corpus medullare and primary white-matter branches to the vermian lobules, including the lingula, centralis, culmen, declive, folium, tuber, pyramis, uvula, and nodulus; and (2) several finer secondary branches to individual folia within the lobules. Surface features of the vermis including the deeper fissures (e.g., preculminate, primary, horizontal, and prepyramidal) and shallower sulci are best delineated by T1-weighted (short TR/short TE) and T2-weighted images, which provide greatest contrast between CSF and parenchyma. Given that the width of the normal vermis varied from 6 to 12 mm in our volunteers, the acquisition of thin slices (less than or equal to 5 mm) was required to minimize volume averaging of the cerebellar hemispheres with the vermis on a midline sagittal MR section. Knowledge of the detailed normal anatomy of the cerebellar vermis on sagittal MR images can assist in the identification of various pathologic alterations.

Adolescent↗

PubMed1989

The cerebellum in sagittal plane--anatomic-MR correlation: 2. The cerebellar hemispheres.

Thin (5-mm) sagittal high-field (1.5-T) MR images of the cerebellar hemispheres display (1) the superior, middle, and inferior cerebellar peduncles; (2) the primary white-matter branches to the hemispheric lobules including the central, anterior, and posterior quadrangular, superior and inferior semilunar, gracile, biventer, tonsil, and flocculus; and (3) several finer secondary white-matter branches to individual folia within the lobules. Surface features of the hemispheres including the deeper fissures (e.g., horizontal, posterolateral, inferior posterior, and inferior anterior) and shallower sulci are best delineated on T1-weighted (short TR/short TE) and T2-weighted (long TR/long TE) sequences, which provide greatest contrast between CSF and parenchyma. Correlations of MR studies of three brain specimens and 11 normal volunteers with microtone sections of the anatomic specimens provides criteria for identifying confidently these structures on routine clinical MR. MR should be useful in identifying, localizing, and quantifying cerebellar disease in patients with clinical deficits.

Cerebellum↗

PubMed1989

Amyloid ophthalmoplegia. Ophthalmoparesis secondary to primary systemic amyloidosis.

We report a patient with primary systemic amyloidosis and orbital involvement associated with ophthalmoparesis. We support this with the first demonstration of eye movement recordings and magnetic resonance imaging (MRI) of such a patient. The patient presented with a restrictive ophthalmoparesis. Eye movement recordings documented slowed horizontal saccades. MRI of orbital structures suggests that all extraocular muscles were enlarged, with possible involvement of their tendinous insertions.

Amyloidosis↗

PubMed1988

Hypoplasia of cerebellar vermal lobules VI and VII in autism.

Autism is a neurologic disorder that severely impairs social, language, and cognitive development. Whether autism involves maldevelopment of neuroanatomical structures is not known. The size of the cerebellar vermis in patients with autism was measured on magnetic resonance scans and compared with its size in controls. The neocerebellar vermal lobules VI and VII were found to be significantly smaller in the patients. This appeared to be a result of developmental hypoplasia rather than shrinkage or deterioration after full development had been achieved. In contrast, the adjacent vermal lobules I to V, which are ontogenetically, developmentally, and anatomically distinct from lobules VI and VII, were found to be of normal size. Maldevelopment of the vermal neocerebellum had occurred in both retarded and nonretarded patients with autism. This localized maldevelopment may serve as a temporal marker to identify the events that damage the brain in autism, as well as other neural structures that may be concomitantly damaged. Our findings suggest that in patients with autism, neocerebellar abnormality may directly impair cognitive functions that some investigators have attributed to the neocerebellum; may indirectly affect, through its connections to the brain stem, hypothalamus, and thalamus, the development and functioning of one or more systems involved in cognitive, sensory, autonomic, and motor activities; or may occur concomitantly with damage to other neural sites whose dysfunction directly underlies the cognitive deficits in autism.

Adolescent↗

PubMed1988

Rhinocerebral mucormycosis: results of aggressive surgical debridement and amphotericin B.

Rhinocerebral mucormycosis is a fulminant, devastating fungal disease. The use of amphotericin B, combined with aggressive surgical debridement, has increased survival rates from approximately 20% to 70%. Eleven patients with this rare disease have been treated over the past 6 years. Therapy with amphotericin B was begun in all patients as soon as the diagnosis of mucormycosis was suspected. Seven patients underwent aggressive surgical debridement; all seven had disease involving the sphenoethmoidal complex, requiring external ethmoidectomy with or without sphenoidotomy. Six patients had maxillary sinus disease, requiring Caldwell-Luc antrostomy or maxillectomy. Three patients required orbital exenteration. Surgery was performed within 24 hours of diagnosis on all but two of our patients. Despite prompt diagnosis, aggressive surgical debridement, therapy with amphotericin B, and correction of metabolic acidosis, our mortality rate was 82%. Rhinocerebral mucormycosis remains a rapidly progressive, frequently fatal disease.

Adolescent↗

PubMed1988

MR imaging of cerebellopontine angle and internal auditory canal lesions at 1.5 T.

The high-field, thin-section (3-5 mm) MR imaging characteristics of 49 cerebellopontine angle and internal auditory canal lesions were reviewed. The diverse abnormalities include 20 acoustic neurinomas, eight neurinomas of other cranial nerves (six involving the fifth cranial nerve and two involving cranial nerves IX-XI), seven meningiomas, five subdural fluid collections, four brainstem tumors with exophytic components, three glomus jugulare tumors, one epidermoid tumor, and one basilar artery aneurysm. T1-, T2-, and proton-density-weighted images were obtained in all cases. T1-weighted images most accurately showed the margins of the seventh and eighth nerves in the internal auditory canal and were most sensitive in detecting small tumors in the cerebellopontine angle. Differentiation of meningioma from acoustic neurinoma by MR was provided most reliably by separation of the meningioma from the porus acusticus and seventh and eighth nerves and not by signal-intensity differences. A hypointense vascular rim was noted on MR in seven of 13 extracanalicular acoustic tumors and in three of seven meningiomas.

Adolescent↗

PubMed1988

MR contrast enhancement of intracranial lesions with Gd-DTPA.

Gd-DTPA is a paramagnetic contrast agent for MR that produces enhancement of lesions on T1-weighted images. Since it does not cross the intact blood-brain barrier (BBB), Gd-DTPA enhances only those pathologic processes that are associated with breakdown of the BBB and structures or lesions that are devoid of a BBB. Gd-DTPA improves conspicuity, helps characterize and delineate the extent of lesions, and increases the sensitivity for detection of cerebral abnormalities.

Brain Diseases↗

PubMed1987

Increased detection of intracranial metastases with intravenous Gd-DTPA.

Three patients with intracranial metastases were studied with magnetic resonance imaging at 1.5 T before and after intravenous administration of 0.1 mmol/kg gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). Axial pre- and postcontrast images demonstrated a total of six and 38 metastases, respectively. Of the 35 lesions detected only after administration of contrast material, all were less than 10 mm, and none had evidence of surrounding edema. Lesion conspicuity was comparable on postcontrast mixed (T1, proton density, and T2) images and T1-weighted images, indicating the feasibility of effectively screening for metastases with a single postcontrast spin-echo sequence providing mixed and T2-weighted images. Sagittal and coronal images depicted temporal lobe lesions not seen on axial images. No discomfort, side effects, or complications resulted from the contrast medium. The detection of additional lesions with Gd-DTPA increased the radiologic suspicion of metastatic disease, revealed locations more favorable for biopsy, prompted the search for a primary tumor, and modified therapeutic objectives and methods.

Adult↗

PubMed1987

The effect of hemodynamically significant carotid artery disease on the hemodynamic status of the cerebral circulation.

Although the presence of a hemodynamically significant carotid artery lesion is commonly used as an indicator of impaired cerebral circulation, the effect of such lesions on cerebral perfusion pressure and cerebral blood flow has never been determined accurately. We used positron emission tomography (PET) to study 19 patients with unilateral hemodynamically significant carotid artery disease (greater than 66% diameter reduction) and no evidence of cerebral infarction. According to PET measurements in the cerebral hemisphere distal to the lesion, 7 patients had normal cerebral hemodynamics, 8 had reduced perfusion pressure with normal blood flow, and 4 had reduced blood flow. Neither the percent stenosis nor the residual lumen diameter in the carotid artery was a reliable indicator of the hemodynamic status of the cerebral circulation. However, a significant relationship was found between the PET measurements of cerebral hemodynamics and the arteriographic circulation pattern (p = 0.006). The role of hemodynamic factors in the pathogenesis and treatment of cerebrovascular disease cannot be determined from the severity of carotid artery disease alone.

Aged↗

PubMed1985

Thoracic wall involvement by Hodgkin disease and non-Hodgkin lymphoma: CT evaluation.

Thoracic computed tomographic (CT) scans of 250 patients with newly diagnosed or recurrent lymphoma revealed thoracic wall involvement in 24 patients (11 with Hodgkin disease, 13 with non-Hodgkin lymphoma). Thoracic wall involvement occurred without contiguous mediastinal or parenchymal involvement in 17 patients. Of these, 13 patients had masses beneath the pectoralis muscles or within the breast, and four had masses arising from the ribs. Five additional patients had mediastinal masses with thymic involvement and parasternal extension through the thoracic wall. Pulmonary parenchymal lymphoma with thoracic wall invasion was noted in the remaining two patients. In five of nine patients receiving radiation therapy, treatment plans were modified by CT demonstration of thoracic wall lymphoma.

Adolescent↗

PubMed1984

Computed tomography of fatal hepatic rupture due to peliosis hepatis.

Hepatic rupture with subcapsular hematoma and hemoperitoneum is shown by CT in a patient with peliosis hepatis. Peliosis hepatis is pathologically characterized by blood-filled cystic spaces in the liver associated with the administration of anabolic androgenic steroids or oral contraceptive agents, particularly those with large components of estrogen. We report a fatal case in a patient receiving diethylstilbestrol for 3 years. In patients receiving these medications, peliosis hepatis should be considered in the differential diagnosis of low attenuation areas in the liver by CT. These patients are subject to increased risk of spontaneous hepatic rupture.

Aged↗

PubMed1984

Papillary renal cell carcinoma: CT and sonographic evaluation.

The CT, sonographic, and pathologic appearances of 13 surgically confirmed cases of papillary renal cell carcinoma were reviewed. CT-pathologic correlation was available in all 13 cases. Sonography was performed in eight patients (10 distinct renal masses). CT features closely correlated with the previously established clinicopathologic and angiographic appearances. Papillary renal cell carcinoma demonstrated low stage at presentation in most cases (10 of 13 had stage I or II), had a high frequency of calcification (seven), and had less enhancement (diminished vascularity) than typical hypernephroma on CT scans. No consistent sonographic pattern existed; one of 10 masses was hyperechoic, five were hypoechoic, and four were isoechoic compared with normal kidney cortex. On the basis of these observations, a prospective CT diagnosis of papillary renal cell carcinoma can be confidently made in many circumstances. This is particularly important when renal-sparing surgery is a clinical consideration.

Adult↗

PubMedDate not supplied

Cortical atrophy and cognitive performance in infantile nephropathic cystinosis.

A group of children and adolescents with infantile nephropathic cystinosis underwent cognitive testing and were examined for cortical atrophy using magnetic resonance imaging or computed tomography. Ten of 11 patients demonstrated cortical atrophy. A consistent pattern of lower cognitive performance was found in patients with greater atrophy; however, only the relationship between atrophy and short-term memory approached statistical significance. In addition, evidence for greater impairment of visual memory than of other cognitive functions was observed. This latter observation did not appear to be related to the degree of atrophy.

Adolescent↗

PubMedDate not supplied

Neonatal schizencephaly: comparison of brain imaging.

Schizencephaly is a regional disturbance of cerebral hemisphere formation occurring at 3-5 months gestation; neonatal presentation is uncommon. Three neonates with schizencephaly were evaluated with cranial ultrasonography (US), unenhanced computed tomography (CT), and magnetic resonance imaging (MRI) examinations. Common findings in US, CT, and MRI include parasylvian and midline clefts, size asymmetries of the basal ganglia and thalamus, cerebral parenchymal volume loss, ventriculomegaly, ventricular diverticula, and absence of the septum pellucidum. MRI and CT were superior to US in detecting calcification, gyral and sulcal abnormalities, and parasylvian clefts. MRI alone demonstrated homolateral absence of the sylvian vasculature, small medullary pyramids, low position of the fornix, and the thinning of the corpus callosum. Although US appears adequate as a screening test, MRI best defines the precise pathoanatomic findings of neonatal schizencephaly and allows for the prediction of neurologic outcomes in affected newborns.

Brain↗