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Biomedical subjects

A D Elster

Publications and source records attributed to A D Elster.

At least 19 recordsLinked to original sources
PubMed1992

Autosomal recessive osteopetrosis: bone marrow imaging.

Technetium-99m sulfur colloid scintigraphy was performed prospectively in 12 infants and children with autosomal recessive osteopetrosis, to correlate the appearance of bone marrow stores with advancing age. Baseline images were obtained in all patients, and one to five follow-up images were obtained in eight patients after they began therapy with calcitriol, interferon-gamma, or both. Conventional radiography was performed along with the nuclear studies in all cases. Magnetic resonance (MR) images of the head or lower extremities were also obtained in six patients and were correlated with the scintigraphic findings. Patterns of abnormal distribution of bone marrow appeared to be age-dependent. In patients younger than 1 year, marrow stores were primarily in the skull base and at the ends of the long bones. In patients aged 3-5 years, marrow stores shifted to the diaphyseal regions of long bones and to the calvarium. In the appendicular skeleton, areas of greatest bone marrow activity corresponded to regions of relative decreased opacity on radiographs and areas of intermediate or high signal intensity on T2-weighted MR images. The skull base showed appreciable marrow activity in spite of densely sclerotic bone on radiographs.

Bone Marrow↗
PubMed1992

Cranial imaging in autosomal recessive osteopetrosis. Part I. Facial bones and calvarium.

Cranial imaging studies (radiographs, computed tomographic [CT] scans, magnetic resonance [MR] images, and bone marrow scintigrams) in 13 infants and children with autosomally recessive osteopetrosis were reviewed to characterize patterns of facial and calvarial involvement at presentation and with progression of disease. In the mandible, a characteristic triangular opacity representing calcification within the secondary condylar cartilage ossification center was seen in 10 of the 13 patients. Defective dentition with incomplete enamel formation and/or caries was encountered in all patients. The paranasal sinuses were poorly pneumatized in all patients, but the ethmoid sinuses tended to be the least severely affected. Hypertelorism was present in five of the 13 patients, with a characteristic "space-alien" appearance on frontal radiographs. In younger patients, the calvarium demonstrated a high-attenuation inner table, a broad, low-attenuation diploic space, and a less high-attenuation outer table at CT. In three older children, a "hair-on-end" appearance was seen, which, at bone marrow scintigraphy, corresponded to areas of marked hematopoietic activity. Regions of sclerotic bone demonstrated low signal intensity on both T1- and T2-weighted MR images; areas containing marrow had intermediate signal intensity. These many new radiologic features of osteopetrosis are related to its pathophysiologic characteristics.

Child↗
PubMed1992

Cranial imaging in autosomal recessive osteopetrosis. Part II. Skull base and brain.

The authors reviewed cranial imaging studies (radiographs, computed tomographic scans, and magnetic resonance [MR] images) in 13 infants and children with the autosomal recessive form of osteopetrosis to characterize patterns of skull base, brain, and cranial nerve involvement at presentation and with progression of disease. Marked sclerosis and deposition of osteopetrotic bone was noted along the anterior (but not posterior) occipitomastoid suture (n = 8), at the basioccipital-exoccipital synchondrosis (n = 9), and along the sphenooccipital synchondrosis (n = 8). Endobones, presumably representing unresorbed primitive ossification centers, were seen in the sphenoidal body and basioccipital bone in 11 of the 13 patients. Marked cupping at the basioccipital-exoccipital synchondrosis was observed in three. Neurologic deficits included blindness (n = 11), conductive hearing loss (n = 11), and facial nerve palsies (n = 4). Delayed myelination was seen with MR imaging in two of five retarded infants, including one with a documented coexisting neuronal storage defect. Prominent extracerebral cerebrospinal fluid spaces were present over the frontal lobes in five of the eight developmentally normal patients, representing either subclinical parenchymal disease or a phenomenon related to discordant growth rates between skull and brain.

Brain↗
PubMed1992

Chiari I malformations: clinical and radiologic reappraisal.

Clinical findings and magnetic resonance (MR) images in 68 patients with Chiari I malformations were retrospectively analyzed to identify those radiologic features that correlated best with clinical symptoms. A statistically significant (P = .03) female predominance of the malformation was observed, with a female: male ratio of approximately 3:2. Associated skeletal anomalies were seen in 24% of patients. Syringomyelia was detected in 40% of patients, most commonly between the C-4 and C-6 levels. Of the 25 patients who presented with spinal symptoms, 23 (92%) proved to have a syrinx at MR imaging. When the syrinx extended into the medulla (n = 3), however, brain stem symptoms predominated. Patients with objective brain stem or cerebellar signs had the largest mean tonsillar herniations. Patients with tonsillar herniations greater than 12 mm were invariably symptomatic, but approximately 30% of patients with tonsils herniating 5-10 mm below the foramen magnum were asymptomatic at MR imaging. "Incidental" Chiari I malformations are thus much more common than previously recognized, and careful clinical assessment remains the cornerstone for proper diagnosis and management.

Adolescent↗
PubMed1992

Six-year follow-up of a case of radiation injury following treatment for medulloblastoma.

Recent reports in the literature have documented long-term sequelae of radiation treatment in children, the most notable of which are diminished endocrine functioning and decline in intellectual ability. A case is presented in which both these long-term effects were seen 7 years after radiation treatment for medulloblastoma. Growth hormone and thyroid hormone deficiencies were identified and treated. Full-Scale IQ dropped from the 79th percentile to the 3rd percentile, and neuropsychological functioning ranged from normal to impaired. However, magnetic resonance imaging reveals few direct imaging correlates of J.M.'s neuropsychological deficits. If identified, hormone deficiencies in such patients can be successfully treated; intellectual deficits may present more of a management problem. In this case, cognitive deficits have contributed to considerable difficulty in school; however, with special classes and modifications, the patient is making progress. Our findings indicate that the long-term outcome for children with radiation injury may be improved significantly with hormone therapy and appropriate academic intervention, and argue strongly for systematic, sequential follow-up of such children so that appropriate intervention can be implemented and continued as necessary.

Body Height↗
PubMed1992

Lesions of skin and brain: modern imaging of the neurocutaneous syndromes.

The neurocutaneous syndromes, or phakomatoses, are a diverse group of disorders affecting the skin and CNS. This review highlights some important but lesser known aspects of the more common phakomatoses while concentrating on rarer and more recently discovered syndromes. The roles of newer imaging techniques such as contrast-enhanced MR imaging and three-dimensional CT in the evaluation of these disorders also are discussed.

Brain↗
PubMed1991

Normal pituitary gland: changes in shape, size, and signal intensity during the 1st year of life at MR imaging.

Magnetic resonance images of the pituitary glands in 48 endocrinologically normal neonates and infants were analyzed to determine the changes in pituitary gland size, shape, and signal intensity that occur during the 1st year of life. A progressive increase in the length--but not height--of the gland was seen throughout the 1st year. When corrections for total brain size were made, the pituitary gland was found to diminish in relative cross-sectional area throughout infancy. Upward convexity of the gland was seen in 63% of neonates less than 1 month of age, but in only 4% of infants older than 2 months. Hyperintensity of the adenohypophysis relative to the brain stem was visualized on T1-weighted images in 18 of the 24 (75%) neonates and infants less than 2 months old; this appearance was never seen in older infants. An area of high signal intensity was visualized in the posterior pituitary in 32 of 48 cases (67%), and its visualization was unrelated to age. The neonatal and young infant pituitary gland is thus significantly rounder, brighter, and relatively larger during the first 2 months of life than in later infancy.

Humans↗
PubMed1991

Size and shape of the pituitary gland during pregnancy and post partum: measurement with MR imaging.

Cranial magnetic resonance (MR) imaging was performed in 38 pregnant and postpartum women and 30 nonpregnant age-matched control subjects to establish standards for pituitary gland size and shape during this period. Gland height and infundibulum width were measured on midline T1-weighted sagittal images. Gland convexity or concavity was graded qualitatively. Throughout pregnancy, gland height increased linearly by approximately 0.08 mm/wk. No gland exceeded 10 mm in height during pregnancy. Increases in gland convexity also correlated with progression of pregnancy. The largest glands were seen in the immediate postpartum period; during this period, five of 12 glands measured 10.0-11.8 mm. Beyond the first week post partum, glands rapidly returned to normal size, apparently regardless of the status of breast-feeding. The mean diameter of the infundibulum was 2.2 mm (range, 0.8-4.0 mm). The pituitary gland enlarges throughout pregnancy but should probably not exceed 10 mm during most of this period. Size of up to 12 mm may be acceptable immediately post partum.

Adolescent↗
PubMed1991

Focal high signal on MR scans of the midbrain caused by enlarged perivascular spaces: MR-pathologic correlation.

Punctate and linear foci of abnormal signal were observed near the substantia nigra in the midbrains of 32 (20%) of 157 patients undergoing high-resolution MR imaging of the brainstem. The lesions were most easily seen on long TR/long TE images, where they were of high signal intensity. Their location was consistently in the lower mesencephalon near the junction of the substantia nigra and cerebral peduncle. Unilateral lesions were observed in 18 cases, while bilateral lesions were noted in 14. A review of anatomic specimens revealed the constant presence of penetrating branches of the collicular or accessory collicular arteries in this location. Enlarged perivascular spaces around these vessels were frequently seen in the specimens and probably account for punctate and linear foci observed on high-resolution MR images of the midbrain.

Adult↗
PubMed1991

An analysis of the natural history of cavernous angiomas.

The advent of magnetic resonance (MR) imaging has permitted the recognition of many angiographically occult vascular malformations before the development of complications and subsequent surgical removal. This study reviews all patients at one institution who had radiographically identifiable vascular malformations believed to represent cavernous angiomas in order to obtain information on the natural history of this particular lesion. All 8131 craniospinal MR images performed at our medical center from January 1, 1986, to November 30, 1989, were reviewed, and 32 patients were identified with 76 lesions meeting the MR imaging criteria for cavernous angioma. Medical histories, physical examination records, and other data from these patients were then reviewed to determine the frequency of complications. Their mean age at latest follow-up examination (or at surgical removal of the lesion) was 37.6 years (range 16 to 72 years). Sixteen patients (50%) had a history of seizures, seven (22%) had focal neurological deficits, and three (9%) had clinically significant hemorrhage attributable to the cavernous angioma; six patients (19%) were asymptomatic. The estimated risk of hemorrhage for this population is 0.25%/person-year of exposure; the estimated risk of seizure development is 1.51%/person-year. Eight patients underwent surgical procedures, resulting in improved seizure control and/or lessened neurological deficit. Although these lesions are often excised with relative ease and minimal morbidity, the potential risks and benefits of surgery must be weighed carefully before removal of these relatively benign malformations.

Adolescent↗
PubMed1991

Amaurosis fugax due to pituitary tumor.

Amaurosis fugax in a younger person in whom premature atherosclerotic disease and cardiac emboli have been eliminated is usually benign. We describe a 25-year-old man with recurrent painless left monocular visual loss lasting from 5 to 45 minutes. Initial physical examination, carotid ultrasound, and electrocardiogram were normal. Goldmann visual field testing demonstrated a small, left paracentral defect. Neuroimaging studies were initially declined for economic reasons, but later a magnetic resonance image disclosed a large pituitary tumor displacing the left optic nerve and chiasm. The tumor was removed via a transphenoidal approach, and the episodic visual symptoms disappeared. We stress that amaurosis fugax in young patients is not necessarily benign. A specific etiology should be diligently sought, particularly when ocular signs are present.

Adenoma↗
PubMed1991

Seasonality of triplet births in the United States.

Birth data on 1050 sets of triplets delivered in the United States from 1985 to 1988 were analyzed to establish whether seasonal variations in the number of triplet births occur. These data were compared to live birth data from the entire United States population over a similar period; the US data exhibit a seasonal variation with a peak in late summer. Seasonality in the number of triplet births was noted, and it differed significantly (p = 0.01) from that of the entire US population. A large peak in triplet births was seen in the spring (April-May) and a smaller peak in late summer (August-September). Only minor differences in these trends could be observed when triplet data were stratified by cause of pregnancy (spontaneous versus drug-induced ovulation) or corrected for the shorter gestations of triplet pregnancies.

Birth Rate↗
PubMed1991

Birth weight standards for triplets under modern obstetric care in the United States, 1984-1989.

Birth data were reviewed on 3321 live-born infants from 1138 triplet pregnancies delivered in the United States between 1984-1989. The three major etiologies for the multiple gestations were fertility drugs (50%), spontaneous (38%), and in vitro methods (9%). The average length of gestation was 33.8 weeks and the mean birth weight was 1911 g. Neonatal birth weight curves for triplet infants born alive in the third trimester were plotted. From 26-35 weeks, the average triplet newborn has a weight corresponding to approximately the 30th percentile level compared with singletons. After 35 weeks, triplet birth weights fall progressively behind those of singletons, reaching the tenth percentile at 38 weeks. Multiple epidemiologic factors were analyzed to determine their effect upon neonatal birth weight and length of gestation. Factors predicting higher than average birth weight included male sex, increasing maternal age, increasing maternal height and weight, maternal weight gain, and maternal parity. The length of gestation was found to correlate with maternal age, weight gain, and parity. No significant association between fertility method and gestational age or weight could be identified. This large data base provides the first comprehensive percentile birth weight rankings for modernly managed triplet gestations in the United States population. A regression equation is presented which accurately predicts mean triplet birth weight in the third trimester and which suggests that a nearly linear weight gain of approximately 150 g per week per fetus should be expected in this period.

Adult↗
PubMed1990

Sexual dimorphism of the human corpus callosum studied by magnetic resonance imaging: fact, fallacy and statistical confidence.

Magnetic resonance (MR) imaging was performed in 120 normal right-handed individuals (60 males, 60 females) to clarify existing contradictory data concerning possible sexual dimorphism of the human corpus callosum (CC). Five linear and three area measurements of the CC and brain were obtained directly at the MR scanner console from midline sagittal T1-weighted images. The anteroposterior length of the CC was significantly larger in males than in females (p = 0.0005). No other differences in absolute callosal measurements between the sexes could be demonstrated. However, several size ratios did achieve statistical significance (p less than 0.05), being consistently larger in females: splenial width/length CC, splenial width/brain length, and area of CC/area of brain. Where no statistically significant differences were obtained, precision, tolerance, and confidence interval calculations are presented. The data in this large series support a limited but definite sexual dimorphism of the CC in right-handed individuals.

Adult↗
PubMed1990

Cranial postoperative site: assessment with contrast-enhanced MR imaging.

To define duration and patterns of postoperative contrast material enhancement, the authors evaluated magnetic resonance (MR) images obtained with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 46 patients who had undergone major intracranial surgery. Intervals between surgery and MR imaging ranged from 1 day to 40 years (median, 1.3 years). Moderate or marked brain and dural enhancement was noted in nearly every patient imaged within 3 months of surgery, but all brain enhancement was gone by 1 year. Abnormal dural enhancement was noted in every patient imaged within 1 year of surgery and in approximately 50% at 1-2 years afterward. One patient had persistent mild enhancement of the dura 40 years after surgery. MR images revealed enhancement in several sites not frequently recognized on computed tomographic (CT) scans. Brain and meningeal enhancement with Gd-DTPA at cranial operative sites was more extensive and persisted much longer than is commonly seen on contrast-enhanced CT scans. Enhancement of the brain or pia mater does not normally last beyond 1 year, but dural enhancement may persist for decades.

Adult↗
PubMed1990

Pseudolayering of Gd-DTPA in the urinary bladder.

When excreted gadolinium diethylenetriaminepentaacetic acid (DTPA) collects in the bladder of a supine patient during magnetic resonance (MR) imaging, a puzzling pattern of signal intensities is noted. A gradual change in urine signal intensity with progressive addition of Gd-DTPA does not occur; instead, three sharply defined "layers" are seen both on T1- and T2-weighted images within the urine-Gd-DTPA mixture. The physical basis for this triple-layering phenomenon was investigated. A bladder phantom was constructed to reproduce the phenomenon. T1 and T2 relaxivities of urine doped with varying concentrations of Gd-DTPA were measured in vitro; measured signal intensities corresponded closely to predicted intensities. Early urine concentrations of excreted Gd-DTPA may be relatively high (10-40 mmol/L), resulting in extremely short T1 and T2 values (less than 30 msec). These extremely short relaxation times cause an artifactual pseudolayering of signal within the urine-Gd-DTPA mixture.

Contrast Media↗
PubMed1990

Pituitary gland: MR imaging of physiologic hypertrophy in adolescence.

The size and shape of pituitary glands in 169 children, adolescents, and young adults were analyzed with T1-weighted sagittal magnetic resonance (MR) images. In patients younger than 12 years old, no pituitary gland was found to be more than 6 mm in height. In adolescents, definite evidence for physiologic (pubertal) pituitary hypertrophy was seen in both sexes, although it was much more prominent in girls. The pituitary glands of four of 32 teenage girls measured 8-10 mm, but no teenage boy had a gland taller than 7 mm. Young adults aged 21-30 years had significantly (P less than .05) smaller glands than teenagers of the same sex. Significant (P = .0001) variations in the shape of the pituitary glands according to patient age and sex were also noted. Convex upper margins were seen in 56% of teenage girls, while this shape was noted in only 18% of the remaining patients of either sex. In eight of 32 teenage girls (25%) the pituitary glands were nearly spherical on sagittal images; this shape was not recorded in any other group. The normal maturation sequence of the pituitary gland apparently involves a period of physiologic hypertrophy in teenagers. This is manifest in girls by a significant change in both pituitary size and shape, while the glands of boys undergo a transformation in size only.

Adolescent↗