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Biomedical subjects

M Sundaram

Publications and source records attributed to M Sundaram.

At least 199 records · Page 11Linked to original sources
PubMed1988

Computed tomography or magnetic resonance for evaluating the solitary tumor or tumor-like lesion of bone?

Following an abnormal radiograph, an initial 34 patients had both computed tomography (CT) and magnetic resonance (MR) to further characterize and stage a solitary tumor. This experience determined the choice between CT and MR in evaluating the next 55 solitary tumors. The choice of examination depends on the radiologist's ability to characterize the lesion from the radiograph as to its morphology, matrix, and probable histologic nature. The anatomic location, in turn, frequently influences the ability to characterize the lesion. Lesions in long bones can almost always be successfully characterized by radiography and, in these instances, only the MR examination is required to stage the tumor. Radiographic characterization of tumors in flat bones such as the scapula, certain portions of ribs, vertebrae, and pelvis is often difficult or incomplete. In these cases, CT is the preferred initial examination, and if further staging is required to establish the relationship of the tumor to soft tissues or neurovascular structures, the MR examination is done. Because of MR's superiority in staging the tumor and CT's superiority in characterizing the lesion, the initial choice between the two examinations should depend on the radiologist's ability to characterize the lesion from the radiograph. When radiographic depiction of tumor permits assessment of its morphology, matrix and probable histologic nature, (characterization) MR ought to be the next examination solely for staging purposes. It is the anatomic location of the tumor and the radiologist's ability to characterize it that ought to govern the choice of the next examination. Surgical and histopathological findings were known in all patients in this study.

Adolescent↗
PubMed1988

Avascular bone necrosis in an untreated case of chronic myelogenous leukemia.

Hip pain due to aseptic necrosis of the femoral head was the first clinical manifestation of chronic myelogenous leukemia in a 9-year-old white female. An erroneous diagnosis of rheumatoid arthritis was first entertained. Physical examination showed splenomegaly, complete blood count revealed leucocytosis of 359,000. The initial radiograph of the involved hip was negative. Biopsy revealed aseptic necrosis of the femoral head. Chronic myelogenous leukemia (CML) was diagnosed on the basis of the peripheral blood smear and bone marrow biopsy. Two months later, radiograph, radionuclide bone scan, and magnetic resonance imaging (MR) of the involved hip were positive for aseptic necrosis of the femoral head.

Arthritis, Juvenile↗
PubMed1988

Neutropenic colitis: evaluation with computed tomography.

The computed tomography findings of 10 patients with neutropenic colitis are described and illustrated. Seven of these patients had leukemia, one had lymphocytic lymphoma, and two had systemic lupus erythematosus. All patients had colon wall thickening which was either isodense with the normal bowel tissue or showed areas of intramural low density. Air in the thickened bowel wall was seen in six patients. These computed tomography findings in neutropenic patients with fever, abdominal pain, and diarrhea should suggest the diagnosis in most instances, resulting in prompt treatment of this usually life-threatening entity.

Adult↗
PubMed1988

Body computed tomography findings in systemic lupus erythematosus.

Fifty-five computed tomography scans in 27 patients with systemic lupus erythematosus were reviewed. The most frequent indication for scanning was suspected intraabdominal sepsis, and the most frequent finding was mild lymphadenopathy. Renal abnormalities were: subcapsular hematoma, focal defects, overall enlargement, and diminution of size. Other findings included serositis, bowel wall thickening with pneumatosis intestinalis, pancreatic pseudocyst, and hepatic and splenic enlargement. Five abscesses were found that were indistinguishable from other fluid collections. Computed tomography was helpful in clinical evaluation and in some cases changed management.

Abscess↗
PubMed1988

Longitudinal study of the early neuropsychological and cerebral metabolic changes in dementia of the Alzheimer type.

To examine the progression of neuropsychologic and metabolic changes in the early stages of dementia of the Alzheimer type (DAT), we studied 11 midly demented patients longitudinally. Three aspects of neuropsychological function were measured: memory, attention to complex sets and abstract reasoning, and lateralized functions, i.e., language and visuoconstruction. Regional cerebral metabolic rates for glucose were measured in frontal, parietal, and temporal association cortices. Our results show that, in general, memory deficits are the first neuropsychological impairments to occur in DAT, followed by problems with attention to complex cognitive sets and abstract reasoning, which are followed in turn by deficits in language and visuospatial abilities. In addition, neocortical metabolic abnormalities usually precede impairment of neocortically mediated attention and abstract reasoning by 8 to 16 months, and precede impairment of neocortically mediated language and visuospatial function by 12 to 37 months. These findings suggest that the first nonmnestic neuropsychological consequence of neocortical physiological dysfunction in DAT is a loss of attentional capacity. Since neocortical metabolic changes generally precede the appearance of neocortically mediated neuropsychological dysfunction, physiologic dysfunction may exist for some time before cognition is affected.

Aged↗
PubMed1988

Malignant rhabdoid tumor of the thoracic spine.

A case of malignant rhabdoid tumor of the spine and a description of its CT findings are presented. The CT demonstrated a heterogeneous contrast enhancing epidural mass associated with severe bony destruction of the adjacent vertebra and cord compression.

Adolescent↗
PubMed1987

Magnetic resonance imaging of osteosarcoma.

Early magnetic resonance (MR) experience in the evaluation of 14 consecutive long bone intramedullary osteosarcomas demonstrates the need for T1 and T2 weighted pulsing sequences in the staging of this disease. Intramedullary disease is best depicted by coronal T1 weighted pulsing sequences and subtle extra-compartmental disease by T2 weighted axial imaging. Both high intensity and low intensity intra-medullary signals were noted on T2 weighting, while all T1 weighted pulsing sequences showed intra-medullary disease to have low signal intensity. Extraosseous tumor on T2 weighting usually had a high signal, and disease extent was therefore sharply demarcated from uninvolved muscle and its relationship to vessels confidently assessed. MR appears optimally suited for local staging of osteosarcoma, further enhancing the role of radiology in planning limb-salvage surgical techniques.

Bone Neoplasms↗
PubMed1987

High signal intensity soft tissue masses on T1 weighted pulsing sequences.

On T1 weighted pulsing sequences, the majority of soft tissue masses are of low signal intensity and show high intensity signals on T2 weighting. There however is a subset of soft tissue masses of varied histology that shows high signal intensity on T1 weighted pulsing sequences. These masses have either fat or blood in their substance. Lipomatous and hemangiomatous lesions that did not show high-signal intensity on T1 weighting were also encountered and are discussed. Present experience with MRI of soft tissue masses suggests that there is a limited spectrum of entities that produce high-signal intensity T1 weighted soft tissue masses.

Cysts↗
PubMed1987

Decline in cerebral glucose utilisation and cognitive function with aging in Down's syndrome.

The cerebral metabolic rate for glucose (CMRglc) was measured with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in 14 healthy subjects with Down's syndrome, 19 to 33 years old, and in six healthy Down's syndrome subjects over 35 years, two of whom were demented. Dementia was diagnosed from a history of mental deterioration, disorientation and hallucinations. All Down's syndrome subjects were trisomy 21 karyotype. CMRglc also was examined in 15 healthy men aged 20-35 years and in 20 healthy men aged 45-64 years. All subjects were at rest with eyes covered and ears plugged. Mean hemispheric CMRglc in the older Down's syndrome subjects was significantly less, by 23%, than in the young Down's syndrome group; statistically significant decreases in regional metabolism (rCMRglc) also were present in all lobar regions. Comparison of the younger control group with the older control group showed no difference in CMRglc or any rCMRglc (p greater than 0.05). Assessment of language, visuospatial ability, attention and memory showed significant reductions in test scores of the old as compared with the young Down's syndrome subjects. These results show that significant age differences in CMRglc and rCMRglc occur in Down's syndrome but not in healthy controls, and that, although only some older Down's syndrome subjects are demented, significant age reductions in neuropsychologic variables occur in all of them.

Adolescent↗
PubMed1987

Rate of ventricular enlargement in dementia of the Alzheimer type correlates with rate of neuropsychological deterioration.

We studied twelve men and six women with dementia of the Alzheimer type (DAT) and twelve healthy men at intervals of 6 months to 5 years. In the male DAT patients, mean CT rates of enlargement of third ventricle and of total lateral ventricular volumes differed significantly from zero and exceeded respective control values (p less than 0.05). The rate of neuropsychological decline correlated with rates of enlargement of the third ventricle or right lateral ventricle. Women with DAT also had significant rates of enlargement of the third and total lateral ventricles. The rate of lateral ventricular dilatation discriminated DAT patients from controls.

Aged↗
PubMed1987

Soft-tissue masses: histologic basis for decreased signal (short T2) on T2-weighted MR images.

Most soft-tissue masses and tumors of various etiologies and histologies have high signal intensity on T2-weighted pulse sequences (long T2). Of 47 soft-tissue masses, seven had a low signal (short T2) on T2-weighted pulse sequences. All seven masses were tumors, and histologic review showed that their composition differed from that of the other 40 lesions with a long T2 in that the seven masses were relatively acellular and had more collagen. The tumors with a short T2 included one malignant and six benign soft-tissue tumors. Malignant fibrous histiocytoma and aggressive fibromatosis showed paradoxical signal intensities in that they showed both long and short T2. All of the tumors with low signal intensity on T2-weighted images had significant fibrous elements and marked hypocellularity. This study suggests that the less commonly encountered short T2 may be seen in both benign and malignant soft-tissue lesions. A part of the explanation for the low signal on T2-weighted sequences appears to be the relative acellularity and abundant collagen of these tumors in comparison with those that have the same histologic diagnoses but show a high signal. The histologic composition of the tumor rather than the histologic diagnosis appears to influence the MR signal on T2-weighted sequences.

Collagen↗