Search PubMed⌕ Search

Biomedical subjects

A D Elster

Publications and source records attributed to A D Elster.

At least 19 recordsLinked to original sources
PubMed1995

Suture closure in the human chondrocranium: CT assessment.

PURPOSE: To chronicle the development of ossification centers, sutures, and synchondroses in the chondrocranium throughout childhood by using computed tomography (CT). MATERIALS AND METHODS: One hundred eighty-nine children (age range, newborn to 18 years; median age, 4.0 years) without skull base deformity were referred for cranial CT. The closure of 18 sutures and synchondroses was graded. RESULTS: In the occipital bone at birth, six components were identified. The Kerckring ossicle rapidly fused to the supraoccipital bone within the 1st month. At age 1-3 years, the posterior and anterior intraoccipital synchondroses began to fuse. The occipitomastoidal, petro-occipital, and spheno-occipital synchondroses remained partially open into the teenage years. In the sphenoid bone at birth, 13 ossification centers were identified; most assimilated into the sphenoidal body during the first 2 years. Pneumatization of the sphenoid sinus appeared at age 1-2 years and advanced posteriorly over the next 3-5 years. CONCLUSION: The complex process of skull base development is chronicled, which provides CT standards for judgment of the patterns and timing of sutural or synchondrosal closure.

Adolescent↗
PubMed1995

Postnatal development of the central skull base: normal variants.

PURPOSE: To illustrate the normal variants and developmental anomalies of the skull base on computed tomographic (CT) scans. MATERIALS AND METHODS: One hundred eighty-nine children (age range, newborn to 18 years; median age, 4.0 years) without skull base deformity were referred for cranial CT. Normal developmental variants in the sphenoid and occipital bones were characterized. RESULTS: Sixteen normal variants of central skull base development were identified including anterior foramen in the presphenoid, remnant of the craniopharyngeal canal in the anterior portion of the postsphenoid, rounded defects in the central sphenoid, clefts and fissures along the basiocciput and basisphenoid, basioticum variants, notochordal remnant in the midline of the basiocciput, and fusion variants of the Kerckring ossicle with the supraoccipital portion of the occipital bone. CONCLUSION: The location and CT appearance of the 16 variants and anomalies are related to the known embryologic origin of this region. Recognition of such variants may prove necessary in evaluation of patients with skeletal dysplasias and disorders of skull base development.

Adolescent↗
PubMed1995

Lumbar spondylolysis: reactive marrow changes seen in adjacent pedicles on MR images.

OBJECTIVE: In a search for ancillary MR findings for the diagnosis of spondylolysis, we performed a retrospective study to characterize changes in MR signal intensity of marrow within lumbar pedicles at the level of a spondylolytic defect. These reactive marrow changes were classified according to the anatomic-pathologic scheme developed for degenerative disk disease by Modic et al. MATERIALS AND METHODS: Two neuroradiologists retrospectively reviewed MR images of 60 patients with lumbar spondylolysis confirmed by conventional radiography or CT. The MR signal of each pedicle at the level of a pars defect was compared on T1- and T2-weighted sagittal images to that at the next higher level. When both observers concurred that the signal of the involved pedicle differed significantly from that of its neighbor, this signal change was classified into one of three types (type I: hypointense on T1-weighted images, hyperintense on T2-weighted images; type II: hyperintense on T1-weighted images, isointense or hyperintense on T2-weighted images; type III: hypointense on both T1- and T2-weighted images). RESULTS: Changes in MR signal intensity of pedicles adjacent to spondylolytic defects were observed in 24 (40%) of the 60 patients. Type I changes were seen in three patients, all less than 24 years old. Type II changes were seen in 17 patients with a median age of 35 years. Type III changes were seen in four patients with a median age of 51 years. The distribution of changes in signal intensity in the pedicle as a function of age was significant (p = .001). CONCLUSION: Categories of changes in MR signal intensity, similar to those described adjacent to degenerating disks, can be seen in lumbar pedicles adjacent to a spondylolytic defect of the pars interarticularis and are distributed as a function of age. Awareness of this finding may aid in establishing the correct diagnosis of spondylolysis on MR imaging and prevent erroneous interpretation of abnormal signal intensity in the pedicles in these patients.

Adult↗
PubMed1995

Lumbar spondylolysis without spondylolisthesis: recognition of isolated posterior element subluxation on sagittal MR.

PURPOSE: To document the occurrence of isolated dorsal subluxation of posterior elements in cases of lumbar spondylolysis without spondylolisthesis both quantitatively (using spinal canal measurements) and qualitatively (by visual inspection) on sagittal MR images. METHODS: Retrospective analysis identified 63 patients with lumbar spondylolysis (confirmed by CT or conventional radiography) who had undergone MR imaging. From these we identified 12 patients with pars interarticularis defects but no evidence of spondylolisthesis. Measurements of anteroposterior spinal canal diameters were performed in these 12 patients to ascertain whether the sagittal canal diameter at the level of the spondylolysis exceeded the normal range as determined from 100 control subjects. RESULTS: In 9 of 12 patients the spinal canal was abnormally widened at the level of the spondylolysis because of dorsal subluxation of posterior elements. In 5 of these patients, the subluxation was readily visible on midline sagittal MR images. In 4 patients, spinal canal measurements were necessary to document this phenomenon. CONCLUSION: In the majority of patients with spondylolysis but without spondylolisthesis, sagittal MR images can show isolated dorsal subluxation of posterior spinal elements.

Adolescent↗
PubMed1995

Seizure-induced transient hippocampal abnormalities on MR: correlation with positron emission tomography and electroencephalography.

We report transient focal abnormalities on MR in a patient having frequent electrographic seizures that were not obvious clinically. Marked mass effect (confirmed with volumetric studies) and abnormal T2 signal intensity in the right hippocampal region correlated with electroencephalographic ictal activity and with increased positron-emitting radiotracer uptake in the medial temporal lobe. The follow-up MR 2 months later, after electroencephalography findings normalized, revealed no hippocampal abnormalities.

Aged↗
PubMed1994

A method for using MR to evaluate the effects of cardiovascular disease on the brain: the cardiovascular health study.

PURPOSE: To do a pilot study for the Cardiovascular Health Study (a population-based, longitudinal study of coronary heart disease and stroke in adults 65 years of age and older designed to identify risk factors related to cerebrovascular disease, particularly stroke): (a) to determine the feasibility of adding brain MR to the full-scale study; (b) to evaluate the reliability of standardized MR image interpretation in a multicenter study; and (c) to compare the prevalence of stroke determined by MR with that by clinical history. METHODS: Protocol-defined MR studies were performed in 100 subjects with clinical histories of stroke and 203 subjects without reported histories of stroke. MR scans were independently evaluated by two trained neuroradiologists for the presence of small (< or = 3 mm) and large (> 3 mm) "infarctlike" lesions. The sizes of the cerebral sulci and lateral ventricles and the extent of white matter disease were graded on a scale of 0 to 9. RESULTS: Eighty percent of the Cardiovascular Health Study participants who were invited to undergo MR studies agreed to do so; 95% of those agreeing to the procedure successfully completed the exams. Intrareader and interreader reliability of infarctlike lesion identification was high for large lesions (kappa, 0.71 and 0.78, respectively) but not for small lesions (kappa, 0.71 and 0.32, respectively). Relaxed intrareader and interreader kappa scores for sulcal and ventricular sizes and extent of white matter disease were greater than 0.8 MR evidence of infarctlike lesions was present in 77% of the participants with histories of stroke but was also present in 23% of the participants without clinical histories of stroke. Seventy-nine percent of the infarctlike lesions were larger than 3 mm. CONCLUSIONS: This preliminary study indicates that a large, prospective, epidemiologic study of elderly subjects using MR scans of the brain for identification of cerebrovascular disease is feasible and that the interpretative results are reproducible, and suggests that MR evidence of stroke is more prevalent than reported clinical history of stroke.

Aged↗
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↗