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Biomedical subjects

D B Mendelsohn

Publications and source records attributed to D B Mendelsohn.

At least 19 recordsLinked to original sources
PubMed2000

Reduction of corpus callosum growth after severe traumatic brain injury in children.

OBJECTIVE: To study effects of closed head injury (CHI) severity on development of corpus callosum (CC) in children, using MRI. BACKGROUND: Vulnerability of CC to diffuse axonal injury has been shown in adults and children by neuropathologic and MRI studies. Given continued development of CC through the second decade, serial MRI could characterize effects of CHI on CC growth in children. METHOD: MRI performed at 3 and 36 months after severe (mean age = 10.3 years, n = 25) and mild to moderate (mean age = 9.7 years, n = 28) CHI. Mild to moderate and severe CHI groups did not differ in demographic features. Morphometry of T1-weighted midsagittal CC by two operators with satisfactory interrater reliability yielded uncorrected and corrected CC volume. RESULTS: An interaction of occasion with CHI severity was present as CC area decreased from 3 to 36 months in severely injured children and increased in the mild to moderate CHI group. Uncorrected CC area was correlated with acute CHI severity and functional outcome at 36 months postinjury. CONCLUSIONS: Morphometric measurement of CC area provides a useful index of diffuse injury, which is related to functional outcome of CHI in children.

Brain Injuries↗
PubMed2000

Safety of MR scanning in patients with nonferromagnetic aneurysm clips.

The purpose of this study was to report our surveillance of patients with nonferromagnetic aneurysm clips (NFAC) who have undergone magnetic resonance imaging (MRI). Forty-six patients with NFAC underwent MRI over a 7-year period. Medical records were studied for evidence of subjective or objective clinical findings as a result of the MRI scan. In two patients with subjective complaints, computed tomograms (CT) were reviewed and patient interviews conducted. No significant neurologic signs or longterm symptoms were experienced. Two patients did not complete their MRI scans due to transient unilateral head pain in one and head "pressure" in another. CT scans in these patients demonstrated no evidence for hemorrhage or visible change in clip position. We documented no objective adverse outcome of patients undergoing MRI with NFAC, confirming that MRI can be performed safely in patients with nonferromagnetic aneurysm clips. The cause of subjective complaints in two of our patients is unknown.

Adult↗
PubMed1999

Corpus callosum damage and interhemispheric transfer of information following closed head injury in children.

We evaluated the relationship of corpus callosum atrophy and/or lesions on magnetic resonance imaging (MRI) to functional hemispheric disconnection following closed head injury (CHI) in 51 pediatric patients, including mild CHI, moderate to severe CHI with extracallosal lesions, and moderate to severe CHI with callosal atrophy and/or lesions. Interhemispheric transfer of information was assessed using auditory, motor, tactile, and visual tests in patients and in 16 uninjured children. Total and regional callosal areas were measured from the midsagittal MRI slice by morphometry. The corpus callosum lesion group demonstrated a greater right ear advantage on verbal dichotic listening than all other groups. Areas of the posterior corpus callosum were negatively correlated with laterality indices of verbal dichotic listening performance and tachistoscopic identification of verbal material. The relationship of corpus callosum atrophy and/or lesions to asymmetry in dichotic listening is consistent with previous investigation of posttraumatic hemispheric disconnection effects in adults.

Adolescent↗
PubMed1998

Stereotactic pallidotomy and thalamotomy using individual variations of anatomic landmarks for localization.

OBJECTIVE: The optimal choice of imaging and localization for stereotactic surgery for movement disorders remains uncertain, with controversy surrounding the use of microelectrode recording and the role of distortion of magnetic resonance imaging (MRI) scans in reducing the accuracy of lesion placement. We review our experience with 67 pallidotomies and 35 thalamotomies performed without microelectrode recording, using instead individual variations in anatomic landmarks. METHODS: Computed tomography is used as the primary modality, with comparison with carefully angled MRI scans and the use of neural structures, such as the mamillary bodies and the vascular anatomy. Pallidal target sites are chosen immediately lateral and superior to the optic tract on a line bisecting the axis of the peduncle, with macrostimulation guiding the final adjustment of target position. Forty-seven patients undergoing unilateral pallidotomies were studied in the "off" state and the "on" state using a modified Unified Rating Scale for Parkinson's disease (URSP) score and a dyskinesia scale, preoperatively and postoperatively at 2 weeks, 2 months, 6 months, and 12 months. In the 31 patients undergoing thalamotomy, tremor was rated preoperatively and postoperatively as near-complete resolution, partial resolution, and failure. RESULTS: The "off" state Unified Rating Scale for Parkinson's disease motor score declined from 42.0 to 32.2 at 2 weeks after surgery (P < 0.0001, n = 42). The Unified Rating Scale for Parkinson's disease motor score was 34.2 at 2 months (P < 0.0001, n = 35), 29.4 at 6 months (P < 0.0001, n = 27), and 24.9 at 12 months (P = 0.005, n = 12), representing an overall improvement in "off" state motor function of approximately 25 to 40%. The "on" state dyskinesia score fell from 5.5 to 2.0 at 2 weeks (P < 0.0001) and persisted in the later visits. The dyskinesia score for the contralateral side fell from 2.5 preoperatively to 0.26 at 2 weeks, 0.28 at 2 months, 0.22 at 6 months, and 0.0 at 12 months. Of the patients undergoing thalamotomies, 65% experienced near-complete or complete tremor resolution, 23% experienced partial tremor relief, and 13% were considered treatment failures. CONCLUSION: Stereotactic procedures for movement disorders requiring high precision can be safely and successfully performed without the use of microelectrode recording techniques. Meticulous alignment of MRI and computed tomographic scans based on visualized anatomy allows precise lesion placement and avoids the distortion inherent in MRI scans.

Globus Pallidus↗
PubMed1994

Chondroblastoma: classic and confusing appearance at MR imaging.

PURPOSE: To define the characteristics of chondroblastoma at magnetic resonance (MR) imaging and the combination of findings that are diagnostic for chondroblastoma. MATERIALS AND METHODS: From January 1987 through December 1992, 22 patients with histologically confirmed chondroblastoma and prior MR imaging examinations were seen. Patients included 16 men and six women, aged 10-58 years (median, 17 years). Retrospective analysis of findings at MR imaging, plain radiography, computed tomography, and bone scanning was performed. RESULTS: Low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins were well defined with high-resolution T2-weighted (repetition time > or = 1,500 msec, echo time > or = 70 msec) MR imaging. Adjacent bone-marrow and soft-tissue edema and periosteal reactions were more dramatically demonstrated on MR images than on radiographs. Bone marrow edema was prominent in all but five cases. Obvious periosteal reaction and adjacent soft-tissue edema were visible in 17 cases. CONCLUSION: Knowledge of the MR imaging findings of chondroblastoma will allow accurate diagnosis and help avoid confusion with infection and aggressive neoplasms.

Adolescent↗
PubMed1994

Dissociation between delayed alternation and memory after pediatric head injury: relationship to MRI findings.

This study investigated the usefulness of a delayed alternation task in characterizing the cognitive sequelae of closed head injury in children and adolescents. Verbal learning and memory (California Verbal Learning Test) were also studied for comparison. Sixty-two closed head injury patients (mean age, 9.6 years), who were studied after an average postinjury interval of 20 months, were divided according to both their lowest postresuscitation Glasgow Coma Scale score (3 to 8 versus 9 to 15) and age range (5 to 7 years versus 8 to 16 years) at the time of testing. Magnetic resonance imaging was performed to evaluate the relationship of focal brain lesions to cognitive and memory performance. Fifty-six neurologically normal children (mean age, 9.9 years) were tested on the same measures. The results disclosed no relationship between delayed alternation performance and severity of injury. In contrast, verbal memory was impaired in the severely-injured patients, relative to both controls and less severely-injured patients. Frontal lobe (but not extrafrontal) lesion size incremented the Glasgow Coma Scale score in predicting verbal memory, but there was no relationship between focal brain lesions and delayed alternation performance. In contrast to the tendency for more efficient delayed alternation performance in the 5- to 7-year-old subjects than in the 8- to 16-year-old subjects, verbal memory significantly improved with age in the closed head injury and control groups. Notwithstanding our essentially negative findings for delayed alternation, it is possible that this task may be useful for assessing frontal lobe injury in younger children or infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Corpus callosum lesions after closed head injury in children: MRI, clinical features and outcome.

Thirty-four children who sustained moderate to severe closed head injury underwent magnetic resonance imaging (MRI). Eight (24%) had MRI evidence of corpus callosum injury, most commonly within the posterior body and splenium. In contradistinction to reports in adults, there was no definite relationship between callosal injury and lower initial Glasgow Coma Scale scores, nor was there a significantly higher incidence of primary brain-stem lesions, diffuse axonal shear injury or intraventricular hemorrhage. In none of these 8 children did the initial admission computed tomography show evidence of callosal injury. Callosal injuries on MRI are not necessarily a poor prognostic finding, the majority of the 8 children showing good functional recovery.

Adolescent↗
PubMed1991

The neuroradiology of visual disturbances.

The neuroradiology of visual deficits has advanced dramatically in recent years. Plain film evaluation of the orbit and face remains useful in the emergency room for the evaluation of trauma. High-resolution coronal CT remains the method of choice in the assessment of serious injury to the orbit and in cases of penetrating metallic foreign body. The contrast-enhanced orbital CT provides useful information in cases of tumor and infection and when the bones of the face or skull are involved. MRI has largely replaced CT in the search for brain infarct, brain tumor, and cerebral inflammatory and demyelinating processes. MRI is the study of choice in all cases of sellar and parasellar disease. It offers high-resolution images in any plane. GTPA enhancement has provided additional information from MRI without significant risk. The final selection of an imaging modality should be based upon the clinical presentation and any physical limitations of the patient.

Brain Neoplasms↗
PubMed1985

Chondrosarcoma of the head and neck--the value of computed tomography.

Chondrosarcomas of the head and neck represent a small percentage and differ in their treatment and prognosis compared with chondrosarcomas elsewhere. Four different cases of chondrosarcoma are presented. One arose intracranially, two in the jaws, one of which followed irradiation for a retinoblastoma, and the last represents chondrosarcomatous transformation in cervical spine Paget disease which is exceptionally rare. Computer tomography (CT) plays an important role in delineating the extent of the tumor with visualization of bony destruction, associated soft-tissue mass, and calcification, information which is extremely important for surgical and therapeutic planning. CT can be vital in suggesting the best possible site for biopsy which is particularly important in this group of neoplasms where the histological diagnosis may be difficult.

Adult↗
PubMed1985

Computed tomography in the diagnosis and treatment of mandibular ameloblastoma: report of cases.

Treatment of ameloblastoma is based on clinical manifestations and radiological features. The value of routine radiographs in determining the extent of the lesion may be limited. Four cases of mandibular ameloblastoma were studied using axial and coronal computed tomography (CT). The soft-tissue mass, destruction of cortical bone, and extension of tumor into the infratemporal fossa and adjacent structures were clearly visualized. These features demonstrate the superiority of CT over conventional radiography in delineating the extent of the lesion, which may be essential to its management.

Adult↗
PubMed1985

Nasopalatine duct cyst.

The nasopalatine duct cyst appears to be an aggressive and symptomatic condition in the South African black population group. Of a total of 114 cases, 30 patients, all blacks, had cysts in excess of 30 mm in diameter. Two patients with large nasopalatine duct cysts, one of which was infected, underwent computed tomography. Computed tomography is an excellent method of demonstrating the extent, bony destruction and relationship of the lesion to neighbouring structures. A review of the subject with clinical and radiological features is presented.

Adult↗
PubMed1985

Intracerebral pneumatoceles following facial trauma: CT findings.

Three patients with delayed frontal intracerebral pneumatoceles following facial injury are presented. In one patient an unusual appearance of bilateral and symmetrical frontal lobe pneumatoceles was demonstrated. While diagnosis is not difficult on routine radiographs, CT is valuable for determining effects on the brain and clearly delineating the fracture site; CT shows the location of the pneumatocele and may show an associated air-fluid level, mass effect or surrounding edema, or rim enhancement following administration of contrast material. The radiological appearances in conjunction with the clinical findings are highly characteristic and should not be mistaken for gas-forming cerebral abscesses.

Adolescent↗
PubMed1984

Migratory redundant lumbar nerve roots. A case report.

A case of migratory redundant cauda equina nerve roots is presented. The redundant roots, seen initially below a spinal stenosis, were shown on repeat study after a short interval to have migrated above the level of stenosis, leaving the lower nerve roots with a normal appearance.

Cauda Equina↗
PubMed1984

Atypical findings on computed tomography in tuberous sclerosis. Case reports.

In 3 patients with tuberous sclerosis computed tomography showed numerous low-density areas suggestive of brain demyelination. In addition, solitary small subependymal calcifications were noted. These features in an infant or child with unexplained seizures should alert one to the diagnosis of tuberous sclerosis.

Cerebral Cortex↗