Search PubMed⌕ Search

Biomedical subjects

W S Ball

Publications and source records attributed to W S Ball.

At least 19 recordsLinked to original sources
PubMed1999

NMR relaxation times in the human brain at 3.0 tesla.

Relaxation time measurements at 3.0 T are reported for both gray and white matter in normal human brain. Measurements were made using a 3.0 T Bruker Biospec magnetic resonance imaging (MRI) scanner in normal adults with no clinical evidence of neurological disease. Nineteen subjects, 8 female and 11 male, were studied for T1 and T2 measurements, and 7 males were studied for T2. Measurements were made using a saturation recovery method for T1, a multiple spin-echo experiment for T2, and a fast low-angle shot (FLASH) sequence with 14 different echo times for T2. Results of the measurements are summarized as follows. Average T1 values measured for gray matter and white matter were 1331 and 832 msec, respectively. Average T2 values measured for gray matter and white matter were 80 and 110 msec, respectively. The average T2 values for occipital and frontal gray matter were 41.6 and 51.8 msec, respectively. Average T2 values for occipital and frontal white matter were 48.4 and 44.7 msec, respectively. ANOVA tests of the measurements revealed that for both gray and white matter there were no significant differences in T1 from one location in the brain to another. T2 in occipital gray matter was significantly higher (0.0001 < P < .0375) than the rest of the gray matter, while T2 in frontal white matter was significantly lower (P < 0.0001). Statistical analysis of cerebral hemispheric differences in relaxation time measurements showed no significant differences in T1 values from the left hemisphere compared with the right, except in insular gray matter, where this difference was significant at P = 0.0320. No significant difference in T2 values existed between the left and right cerebral hemispheres. Significant differences were apparent between male and female relaxation time measurements in brain.

Adult↗
PubMed1998

Research in pediatric radiology: preparing for our future.

The changing healthcare environment challenges the traditional role of academic medicine. Pediatric radiologists involved in research, education and teaching are under pressure to forego such endeavors in favor of increased clinical responsibilities. How we perform research must change if our subspecialty is to survive into the future, as we cannot afford to give up our traditional duties as researchers and educators. To do so could summon the beginning of the end for pediatric radiology. Rather, we must begin the process of restructuring research in pediatric radiology to take into account the efficient use of our resources which provide the greatest return on our investment.

Academic Medical Centers↗
PubMed1998

Central nervous system relapse of treated stage IV neuroblastoma.

Neuroblastoma is the most common extracranial solid tumor in pediatrics. The long-term survival of patients with advanced-stage neuroblastoma has remarkably improved secondary to aggressive treatment protocols including autologous bone marrow transplant (BMT). As a result, a different natural history of this disease is being reported with unusual, late manifestations. The central nervous system (CNS), once a rare site of disease, is being involved with increasing frequency. Appropriate neuroimaging in these patients is important. Two cases of patients with treated stage IV neuroblastoma who developed isolated CNS metastases are presented. The proposed pathogenesis and neuroradiologic manifestations of this complication are reviewed.

Adrenal Gland Neoplasms↗
PubMed1998

Formation of intracerebral cavernous malformations after radiation treatment for central nervous system neoplasia in children.

OBJECT: Radiation is a common treatment modality for pediatric brain tumors. The authors present a retrospective review of six children who developed cerebral cavernous malformations after they underwent radiation treatment for central nervous system (CNS) neoplasia and propose two possible models to explain the formation of cavernous malformations. METHODS: Three boys, aged 13, 9, and 17 years, suffered intracerebral hemorrhages from cerebral cavernous malformations 87, 94, and 120 months, respectively, after they received whole-brain radiation therapy (WBRT) for acute lymphocytic leukemia. A 10-year-old girl and a 19-year-old man developed temporal lobe cavernous malformations 46 and 48 months, respectively, after they received radiation therapy for posterior fossa astrocytomas. A 12-year-old girl developed a temporal lobe cavernous malformation 45 months after WBRT was administered for a medulloblastoma. In all of these cases the cavernous malformation appeared in the irradiated field, was not known to be present prior to radiation therapy, and developed after a latency period following treatment. The incidence of cavernous malformations in these patients suggests that children who undergo radiation therapy of the brain may have an increased risk of hemorrhage. CONCLUSIONS: Two possible models may explain the formation of cavernous malformations following brain radiation in these patients. First, the cavernous malformations may form de novo in response to the radiation. Second, the cavernous malformations may have been present, but radiographically occult, at the time of radiation therapy and may have hemorrhaged in response to the radiation. The authors conclude that cavernous malformations may develop after brain radiation and propose a possible mechanism for this formation.

Adolescent↗
PubMed1998

Proton MR spectroscopic characteristics of pediatric pilocytic astrocytomas.

PURPOSE: We report the common characteristics of juvenile pilocytic astrocytomas revealed by proton MR spectroscopy. METHODS: Eight children with pilocytic astrocytomas were studied with proton MR spectroscopy. The selected sampling volume was approximately 4 cm3, obtained from solid tumor. To localize the sampling volume, we used point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) techniques to acquire long- and short-TE spectra, respectively. Spectra from PRESS and STEAM sequences were processed using Lorentzian-to-Gaussian transformation and exponential apodization, respectively. For PRESS (2000/270) spectra, peaks of creatine, choline, N-acetylaspartate (NAA), and lactate resonances were integrated; for STEAM (2000/20) spectra, we measured the amplitude of the peaks at 3.2, 2.0, 1.3 and 0.9 ppm. RESULTS: An elevated lactate doublet was observed in the PRESS spectra. The choline/NAA ratio was 3.40. The amplitude ratios of the lipid pattern (0.9, 1.3 and 2.0 ppm) to choline were all below one. CONCLUSION: Despite the benign histology of the tumor, which generally lacks necrosis, a lactate signal was detected in all eight patients studied. A dominant lipid pattern was not observed.

Aspartic Acid↗
PubMed1998

Atretic parietal cephaloceles revisited: an enlarging clinical and imaging spectrum?

PURPOSE: We describe imaging features that are clues to the diagnosis of atretic cephaloceles and discuss clinical findings and a possible mechanism by which these lesions develop. METHODS: Eight children (five girls and three boys) ranging in age from 1 day to 3 years 4 months with midline subscalp lesions underwent radiologic examination with CT or MR imaging. In all cases, the lesions were surgically excised and subjected to pathologic examination. Imaging studies and medical records were reviewed retrospectively. RESULTS: Six of eight children had vertical embryonic positioning of the straight sinus with a prominent superior cerebellar cistern. A "spinning-top" configuration of the tentorial incisura, a "cigar-shaped" CSF tract within the interhemispheric fissure, fenestration of the superior sagittal sinus, and "peaking" of the tentorium were associated findings helpful in making this diagnosis. Two of the eight children had findings indistinguishable from focal dermoid, six were developmentally normal, one had mild motor delay, and one died at the age of 3 years. Pathologic examination revealed glial, meningeal (arachnoid), fibrous, and dermal elements. CONCLUSION: Characteristic findings on MR images and CT scans provide clues to the diagnosis of atretic cephalocele. However, even in the presence of abnormal imaging findings, these children may be developmentally normal.

Cerebellum↗
PubMed1997

Trilateral retinoblastoma with suprasellar involvement.

"Trilateral retinoblastoma" (TRB) is the association of a midline intracranial tumor with familial bilateral retinoblastoma. Classically, the intracranial tumor is a pineal region tumor (pineoblastoma) with histology similar to retinoblastoma. We present a 7-month-old child with bilateral orbital retinoblastoma with a third tumor arising in the chiasmatic cistern. The presentation and prognosis of patients with this association differ from those children with "classical" TRB. The presentation, treatment, and outcome are described, with a review of the literature.

Brain Neoplasms↗
PubMed1997

Parry-Romberg syndrome: follow-up imaging during suppressive therapy.

Parry-Romberg syndrome is a poorly--understood disorder characterized by progressive hemifacial atrophy involving the skin, soft tissue, and bone. Involvement of the central nervous system with impairment in neurologic function occurs infrequently. We describe a child with this syndrome in whom central nervous system involvement, documented on serial MRI, played a prominent role. We have attempted to correlate the clinical course with the radiologic findings, and to determine the impact of prednisone and methotrexate on the intracranial lesions.

Brain↗
PubMed1997

Safety and efficacy of sedation in children using a structured sedation program.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of sedating pediatric outpatients in a radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics. MATERIALS AND METHODS: Medical records of 6006 pediatric outpatients who underwent sedation for imaging studies under the guidelines of a structured sedation program were retrospectively reviewed for safety and efficacy of sedation, complications related to sedation, and rate of successful sedation. RESULTS: No cases of cardiovascular or respiratory arrest or fatalities occurred. Four children who required overnight hospitalization because of CNS depression had no sequelae. Forty-eight patients experienced transient respiratory depression that proved responsive to supplemental oxygen. Delayed complications were found in 29 children, none of whom required hospitalization. The rate of sedation failure was approximately 1%. CONCLUSION: Sedation of children can be done in a safe and highly efficacious manner in a hospital radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics.

Adolescent↗
PubMed1996

Intracranial tumors in children: small single-voxel proton MR spectroscopy using short- and long-echo sequences.

We report preliminary experience using single-voxel, proton MR spectroscopy (MRS) employing small voxels of interest, in combination with short and long echo-time protocols, for the assessment of primary intracranial tumors in children. We examined 23 children with primary intracranial tumors detected by MRI, and 32 controls with similar ages, using MRS on a 1.5 T system. Localized single-voxel (3.7 +/- 1.3 cc) proton spectra were obtained with short-echo (2,000/18), stimulated-echo (STEAM) and long-echo (2,000/270) spin-echo (PRESS) protocols. All spectra were evaluated qualitatively; 10 tumor and 19 control spectra were processed for peak area quantification. Small voxels of interest were able to account for tissue heterogeneity. Combined acquisition of short- and long-echo spectra increased the number of detectable metabolites. The solid portion of all tumors exhibited reduced N-acetyl-aspartate (NAA), strong contribution from cholines (Cho) and inositols or glycine, minimal presence of total creatine (tCr), enhanced broad mobile lipid resonances and accumulated lactate. Calculated selected metabolite ratios of Cho/tCr and Cho/NAA were substantially increased from control values. The cystic portions of the masses showed only lipid and lactate peaks.

Adolescent↗