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Biomedical subjects

S I Blaser

Publications and source records attributed to S I Blaser.

16 recordsLinked to original sources
PubMed1992

Aggressive surgical management of craniopharyngiomas in children.

The cases of 50 patients with craniopharyngioma operated on at The Hospital for Sick Children in Toronto between January, 1975, and December, 1989, are reviewed. All patients were under 18 years of age (mean 9.39 years). Headaches, endocrine deficiencies, and visual deficits were the most common symptoms on admission. Forty-five patients underwent what was considered by the surgeon to be total excision of their tumor, and five had subtotal excision. Tumors recurred in 17 patients (mean time of recurrence 32.6 months after surgery). One patient died in the postoperative period and three have been lost to follow-up study. Of the remaining 46 patients, 28 are leading a normal or nearly normal life, although all are receiving endocrine replacement and some have required help to overcome mild deficits in memory or visual acuity. Twelve patients are able to function reasonably well and attend school despite being hampered by intellectual or visual deficits or problems with weight control; four have a significant handicap, and two have died.

Actuarial Analysis↗
PubMed1992

Radiology of the developing central nervous system.

Functional and anatomical imaging of the developing central nervous system continue to engender considerable interest. Structural anomalies have been further defined and catalogued, aiding in the diagnosis and genetic counseling of children with developmental delay. Anomalous development of the brain has recently been linked to certain neuropsychiatric disorders. The natural course of many of the metabolic brain disorders has now been chronicled with imaging studies, rendering standards on which to evaluate efficacy of treatment.

Brain↗
PubMed1991

Arteriopathy and coarctation of the abdominal aorta in children with mucopolysaccharidosis: imaging findings.

Eight children with mucopolysaccharidosis I (MPS I), representing 33% of all children with MPS I seen at our institution during an 18-year period, developed hypertension. Five of these hypertensive children also exhibited symptoms of aortic coarctation. The radiographic evaluation of four of these children with MPS I (three with Hurler syndrome, MPS I H, and one with Scheie disease, MPS I S) and arteriopathy affecting the thoracic aorta, abdominal aorta, and visceral and renal arteries is presented. Hypertension developed in all four children before they were 4 years old; three had differences between upper- and lower-extremity blood pressures. Irregular narrowing of the abdominal aorta with either multiple minor asymmetric wall lesions (n = 2) or abrupt concentric narrowing (n = 2) was present in all children as shown by aortography (n = 3), sonography (n = 3), MR imaging (n = 2), and/or autopsy (n = 1). A variety of other vessels also were involved, including the ascending aorta (n = 1) and vertebral (n = 1), axillary (n = 1), intercostal (n = 2), lumbar (n = 2), mesenteric (n = 3), renal (n = 2), and iliac arteries (n = 3). Autopsy in one child demonstrated thickened heart valves, narrowing of the coronary arteries, and irregularity of the aorta due to deposition of mucopolysaccharide material within the intima. Our series demonstrates various facets of the arteriopathy of MPS I as shown by sonography, MR imaging, and angiography.

Angiography↗
PubMed1991

Benign intrinsic tectal "tumors" in children.

A specific group of intrinsic dorsal midbrain tumors was identified in six children by computerized tomography (CT) and magnetic resonance (MR) imaging. Each patient presented with raised intracranial pressure as a result of hydrocephalus due to obstruction of the sylvian aqueduct. No patient had brain-stem signs referable to the tectal tumor initially or subsequently. All six children underwent cerebrospinal fluid (CSF) diversionary procedures. The radiological features were consistent and specific, with all patients showing tectal calcification or primary increased attenuation of the tectal plate on CT scans. In addition, lack of contrast enhancement was noted initially in four patients and eventually in all six patients. In all patients MR imaging showed a focal tectal tumor distorting the collicular plate with no cystic component and increased signal intensity on T2-weighted images. There has been no evidence of progression in these six patients in the follow-up period ranging from 8 months to 17 years (8 months and 2 1/2, 4 1/2, 8, and 17 years). Diversion of CSF has been the only surgical treatment and no patient underwent deep x-ray therapy. Five patients have had normal intellectual development. In contrast to the majority of previously described periaqueductal and tectal tumors, this group of lesions appeared to be truly benign. The authors suggest that patients presenting with these clinical and radiological features may be managed by CSF diversion, serial examination, and MR imaging.

Adolescent↗
PubMed1991

MR of infectious and inflammatory diseases of the spine.

Magnetic resonance imaging is the study of choice in the evaluation of infectious and inflammatory disease of the spinal cord and spinal column. Not only is the multiplanar imaging a distinct advantage over other modalities, but direct visualization of the soft tissues, including the spinal cord, paraspinal musculature, and disk, is present. The sensitivity of MR, to evaluate infectious processes of the spine, especially when used with gadolinium, has been well documented. This article is an overview of the pathophysiology and MR appearance of various types of inflammation and infection of the spine. Subjects covered include disk space infections, epidural abscess, meningitis, arachnoiditis, and inflammatory mimics of disk space infections. Suggested imaging protocols are stated.

Bacterial Infections↗
PubMed1991

Infectious and inflammatory processes of the spine.

Infectious and inflammatory processes of the spinal column are discussed, including disc space infection, osteomyelitis, epidural abscess, arachnoiditis, and rheumatoid arthritis. The relative sensitivity and specificity of various imaging modalities, as well as the imaging characteristics and utility of these various modalities are given. Emphasis is placed on the use of magnetic resonance imaging.

Arachnoiditis↗
PubMed1989

Magnetic resonance imaging of disturbances in neuronal migration: illustration of an embryologic process.

Twenty-three cases of suspected congenital anomalies involving disorders of cortical proliferation, migration or cortication were retrospectively collected over an 18 month period. Pathologic confirmation was present in five cases. The theoretical sequential stages of cortical development are discussed as keys to the interpretation of MR images of anomalies resulting from arrest of the developmental process. MRI is the imaging modality of choice for suspected defects of cortex formation since it distinguishes gray from white matter, delineates the corticomedullary junction, records details of cortical surfaces, detects abnormal white matter, identifies heterotopias and records unrelated congenital abnormalities. Histopathologic confirmation of two cases of isolated heterotopia and three cases of polymicrogyria were available. Comparative images of MR, CT and pathologic specimens are presented.

Brain↗
PubMed1989

Magnetic resonance imaging of the spine.

The role of magnetic resonance imaging (MRI) for the evaluation of the spine is expanding rapidly. In addition to being noninvasive, MRI offers high soft-tissue contrast and multiplanar imaging capability. MRI examinations of the spine usually include a T1-weighted spin-echo and a T2-weighted spin-echo and/or a gradient-echo sequence. As in other parts of the body, the use of surface coils results in higher-quality examinations. Various methods are employed to reduce the motion artifacts that are particularly troublesome in spine imaging. Paramagnetic contrast agents are used to enhance soft-tissue lesions. The contrast sensitivity of MRI provides a unique means to assess the intervertebral disc, and MRI is rapidly becoming the method of choice for evaluation of disc disease. It is also very sensitive and accurate in the detection of osteomyelitis of the spine. MRI has improved the evaluation of failed back surgery syndrome, and the administration of gadolinium-diethylene trimene pentacidic acid helps to differentiate postsurgical scar from recurrent disc herniation. MRI is an unparalleled tool for the detection and evaluation of intramedullary lesions including syringomyelia, gliomas, hematomas, and lesions associated with dysraphism. It is also useful in many extramedullary intradural processes. In summary, MRI is the best first examination for spinal disease.

Epidural Space↗
PubMed1989

Diagnostic imaging of craniofacial fractures.

This article reviews common fractures involving the facial skeleton and describes their typical radiographic appearance. The roles of conventional radiography, supplemental projections, conventional tomography, and computed tomography are discussed. Nasofrontal, orbital, zygomatic, maxillary, and mandibular fractures are described and illustrated.

Facial Bones↗
PubMedDate not supplied

Serial MR studies in Menkes disease.

We describe a characteristic combination of findings in a patient with Menkes disease who was serially imaged with magnetic resonance over 2 months. Abnormal intracranial vessels were demonstrated as was the progression of white matter disease.

Brain Diseases, Metabolic↗
PubMedDate not supplied

Current management of choroid plexus carcinoma in children.

Eleven children with choroid plexus carcinoma are reviewed with respect to presentation, radiographic diagnosis, treatment and pathologic histology. These cases accumulated over a 33-year period and represent 39% of all of our choroid plexus tumors (n = 28). Characteristically, choroid plexus carcinomas are associated with a poor prognosis for long-term survival. Unfortunately, efforts at total resection are hindered in part by the extreme vascularity of the tumor which itself may be of considerable volume. We have recently treated four children who had biopsy or minimal resection of their tumor after which adjuvant chemotherapy was given. Chemotherapy is not curative but it does cause a reduction in tumor volume and, more importantly, has tended to reduce the tumor vascularity. This allows for a second stage operation which is more safely performed and typically allows for more complete tumor removal. At this point, our length of follow-up is insufficient to conclude if total removal in this manner significantly increases survival but it would seem that consistent gross total removal may be an initial step toward better overall management and prognosis in this tumor type.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Melanotic neuroectodermal tumor of infancy: clinical, radiologic, and pathologic findings in five cases.

Five pathologically proved melanotic neuroectodermal tumors of infancy are reported. These rare neoplasms of infancy exhibit a distinct predilection for the maxillary bone. Three tumors originated in the maxilla, one in the calvaria, and one in the cerebellar vermis. Those occurring in bone did not metastasize but were locally invasive, as reflected in their radiologic appearance. Bone erosion, expansion, hyperostosis, and osteogenesis can occur in the same neoplasm and were appreciated best on CT. MR imaging showed the soft-tissue component and extent of the neoplasm better than CT did. The pathologic findings from all five cases (and one possibly related melanotic tumor of the face) revealed abundant melanin. MR imaging of two melanotic tumors showed isointense T1-weighted and slightly hyperintense T2-weighted signals. This appearance is contrary to that of most melanin-containing tumors, which exhibit enhanced T1 and T2 relaxation, and indicates that variables other than the absolute amount of melanin may determine the MR signal. Clinically, rapid neoplastic growth and excessive melanin production by the tumor cells caused facial disfigurement and visible blue black discoloration. All five melanotic neuroectodermal tumors were resected and the vermian tumor was also irradiated. Four of five children were well and free from disease 1 month to 7 years after resection. The calvarial tumor was incompletely resected and involved the underlying brain, eventually causing death. The clinical, radiologic, and pathologic features of melanotic neuroectodermal tumors of infancy are reviewed. Melanotic neuroectodermal tumors of infancy that involve bone can be diagnosed from the clinical and radiologic findings. Prompt diagnosis and surgical resection are essential for cure.

Cerebellar Neoplasms↗
PubMedDate not supplied

Diagnosis of ruptured intracranial dermoid cyst: value MR over CT.

The CT and MR findings of seven patients with pathologically proved ruptured dermoid cysts were reviewed to analyze the MR characteristics and to see if MR evaluation had significant advantages over CT. In six cases, both CT and MR identified fatty material in the CSF spaces. Hemorrhage complicated preoperative diagnosis in one case. Patterns of extraaxial fat distribution were as follows: intraventricular fat/CSF levels (three patients), generalized subarachnoid spread (six patients), and localized subarachnoid spread with sulcal widening (one patient). There was no correlation between fat distribution and clinical symptoms. MR showed the vascular involvement better than CT did in five of seven cases, and showed extension of the cysts into the skull base in two cases. Signal intensity of the solid mass was low on T1-weighted MR images and inhomogeneously high on T2-weighted images, which correlated pathologically with the presence of crystal cholesterol, hair, sebaceous glands, and epithelial cells in all cases. On MR, brain parenchyma showed little edema or other reaction to the masses, which were typically large. The value of MR over CT in the examination of ruptured dermoid cysts is the conspicuity of the extent of subarachnoid spread, involvement of the extraaxial structures, and evidence of vascular compromise, which can obviate angiography. MR had no advantage over CT in making the initial diagnosis of ruptured dermoid, but it would be the preferred preoperative study.

Adult↗
PubMedDate not supplied

Tuberous sclerosis: increased MR detection using gradient echo techniques.

The case of a child with a pervasive developmental disorder secondary to tuberous sclerosis is presented. Magnetic resonance images demonstrated several areas of decreased signal on both T1- and T2-weighted conventional spin echo sequences. The abnormal areas became more conspicuous on the gradient echo images. The increase in conspicuity of the parenchymal brain lesions in the gradient echo images was presumably secondary to magnetic susceptibility effects.

Brain↗