PubMed Health⌕ Search

Biomedical subjects

S Balachandran

Publications and source records attributed to S Balachandran.

At least 55 records · Page 3Linked to original sources
PubMed1986

Ejection fraction by combined inverse Fourier analysis and second-derivative technique: correlation with isocontour method.

In order to measure ejection fractions (EFs) from nuclear ventriculograms, we devised a semi-automated edge-detection technique based on a combination of inverse Fourier analysis and second-derivative techniques. Initial clinical studies showed that, for the left ventricle, our method gives EF values statistically identical with those obtained using a conventional isocontour technique. For the right ventricle, however, the values obtained using the two methods were somewhat more at variance. Despite requiring a longer processing time, the results obtained with our method are reproducible because less operator intervention is necessary.

Fourier Analysis↗
PubMed1986

Radiation dosimetry considerations in the treatment of cystic suprasellar neoplasms.

Methods and results are given to enable the computation of radiation dose as a function of depth in the wall of a suprasellar cyst containing radioactivity. Both beta- and gamma-emitting nuclides are considered. The methodology considers distribution of the radioactivity on the cyst wall (spherical shell geometry) and distribution uniformly in the fluid (volume geometry).

Beta Particles↗
PubMed1986

111 In-labeled leukocytes in the detection of prosthetic vascular graft infections.

Making a clinical diagnosis of infection in prosthetic vascular grafts is difficult but when undiagnosed, this condition has a high mortality rate. Using Indium-111-labeled white-blood cells, 30 scans were performed in 21 patients suspected of having a prosthetic graft infection. The diagnosis of infected graft was confirmed by surgery in all cases, and lack of infection was established by resolution of symptoms with conservative therapy. Twenty-four hour scans of autologous Indium-111 leukocytes were obtained, and correlative CT studies were done in 11 cases. There were 13 infected grafts at surgery (purulent material present), and scans were positive in all (100% sensitivity); of 17 scans, there were 15 true negatives and two false positives (88% specificity). Using the criteria of gas or fluid around the graft, the sensitivity of CT was only 37% in a small subset of these patients. One-half of the cases in which infection was suspected clinically had no infection and had negative scans. Various types of grafts and graft materials were used, and there was no correlation with presence or absence of infection on the basis of the type of graft. Extragraft infection sites were found in five patients. In conclusion, use of Indium-111 leukocytes has been found to be an accurate and valuable diagnostic method for evaluation of suspected prosthetic vascular graft infection, and to have higher diagnostic accuracy than CT.

Aged↗
PubMed1985

Bremsstrahlung imaging after 32P treatment for residual suprasellar cyst.

A patient with residual suprasellar cystic neoplasm was treated by direct instillation of the 32P colloid. The incidental bremsstrahlung images on a conventional gamma camera helped to localize the pharmaceutical within and outside of the lesion. Advantages of bremsstrahlung imaging and the dosimetry results of phantom studies carried out are described.

Craniopharyngioma↗
PubMed1985

Incidental hydronephrosis on bone scintigraphy: sonographic verification.

We studied 98 kidneys in 55 patients with bone scintiscans and renal sonography. Among the 29 kidneys in which hydronephrosis was suspected on bone scintiscans only 12 were truly hydronephrotic by renal ultrasound. In the other 17 cases extrarenal pelves, postural stasis, early urinary tract obstruction or renal parenchymal disease may have contributed to the discrepant findings. By ultrasound criteria there were no false negative readings for hydronephrosis on scintiscan. While it is safe to interpret absence of hydronephrosis caution should be used in diagnosing hydronephrosis, since less than half of the cases actually will have the disease when suspected on a bone scintiscan.

Bone and Bones↗
PubMed1984

Filiform polyposis in a child with Crohn's disease.

Filiform polyps were demonstrated radiographically in a seven year old child with granulomatous colitis. Most previous reports have been in adult subjects. These slender projections of colonic mucosa and submucosa have a characteristic radiographic appearance on barium enema. It is important to recognize the condition as being benign.

Barium Sulfate↗
PubMed1983

Indium-111 chloride imaging in patients with suspected abscesses: concise communication.

Two hundred and fifty-eight patients with clinically suspected inflammatory processes were studied. Seventy-two images were categorized as true positive; 211 as true negative. There were nine false-positive studies, four of which were due to activity in beds of excised organs. There were six false-negative studies, four of which were due to walled-off abscesses found either at surgery or biopsy. The sensitivity was 92%, the specificity 95%, and the accuracy 94%. This study shows that indium-111 chloride imaging provides a reliable way to locate inflammatory processes and overcomes the disadvantages of other imaging agents, for example gastrointestinal activity or the demonstration of healing surgical wounds with gallium-67, and the false-positive images due to cystic fibrosis and other respiratory diseases, or accessory spleens as seen with In-111-labeled white cells.

Abscess↗
PubMed1982

Bone-marrow imaging with indium-111 chloride in aplastic anemia and myelofibrosis: concise communication.

Twenty-nine patients with aplastic anemia and 11 patients with myelofibrosis were evaluated with indium-111 chloride bone-marrow imaging, ferrokinetics, and bone-marrow core biopsies. There was good correlation between the erythrocyte cellularity of the marrow and the In-111 bone-marrow scan grades in most patients. In some, the overall scan grade tended to underestimate the erythroid elements because the core biopsy had been taken from the area of the greatest radionuclide concentration on the scan. In patients with aplastic anemia, there was good correlation between the plasma iron clearance t1/2 and the scan grade. Less agreement was found in the comparison between the Fe-59 sacral and organ counts and the red-cell iron utilization. In patients with myelofibrosis, there was poor correlation between the surface counts over the sacrum and the red-cell iron utilization. Plasma iron clearances were abnormally short and were unrelated to the transferrin saturation levels. Eighteen patients were studied several times to evaluate their responses to steroid therapy. In all, there was good correlation between the bone-marrow imaging, the erythrocyte cellularity, ferrokinetics, and the patient's response to therapy. Indium-111 bone-marrow imaging is useful both in evaluating marrow erythroid activity and in following the response to therapy in patients with these diseases.

Adolescent↗
PubMed1981

Iodocholesterol adrenal scanning for the detection of adrenal metastases in lung cancer and its clinical significance.

Detection of adrenal metastases is difficult. Since metastatic growth fails to destroy sufficient adrenal tissue to produce clinical symptoms of adrenal insufficiency, and since adrenal metastases have been reported in 28--36% of autopsied patients with primary lung cancer, the authors studied 25 patients with lung cancer by using iodocholesterol adrenal scans. Six patients (24%) were found to have abnormal scans suggestive of adrenal metastases by this technique. Two of these patients were confirmed by biopsy to have adrenal metastases. Four of the six patients died within a mean of six weeks of the positive scan. Iodocholesterol adrenal scanning appears to be a promising noninvasive technique in the detection of adrenal metastases. The prognostic significance of adrenal metastases is discussed.

19-Iodocholesterol↗
PubMed1981

Value of thyroid carcinoma imaging after therapeutic doses of radioiodine.

Thyroid carcinoma scans in the immediate post-therapy period after therapeutic doses of I-131 for well-differentiated thyroid carcinoma showed additional lesions in ten of 24 (42%) patients or on 13 of 42 (31%) occasions, whereas the corresponding pretreatment diagnostic scans done with a small test dose failed to reveal the lesions. In four patients, lesions were only discernible on the regional rectilinear scan views and not on the total-body images. The value of post-therapy scans and the importance of obtaining the regional views are emphasized.

Adenocarcinoma↗
PubMed1980

Functional asplenia in Sezary syndrome.

A case of functional asplenia revealed by radiocolloid scanning is reported in a patient suffering from Sezary syndrome, a lymphoma of cutaneous origin. Heavy, diffuse sinusoidal infiltration of the spleen by the Sezary cells appears to be responsible for the functional asplenia in this case.

Humans↗
PubMed1980

Relative roles of radionuclide scanning and radiographic imaging in eosinophilic granuloma.

Twenty-four skeletal lesions were studied in seven patients with eosinophilic granuloma by radiographic skeletal surveys and radionuclide bone imaging. The radiographs detected 22 (92%) of these lesions and missed only two, whereas the scintiscans identified only 16 (67%) of these lesions, and missed eight. Radiographic skeletal survey and radionuclide bone imaging are complementary procedures in detecting bone lesions in bone marrow disorders, including eosinophilic granuloma. Use of either method alone is fraught with the danger of missing bone lesions of eosinophilic granuloma.

Adolescent↗
PubMed1980

Tumoral calcinosis: scintigraphic studies of an affected family.

Tumoral calcinosis is a rare, familial ectopic calcification syndrome associated with hyperphosphataemia. A family in which seven of 13 siblings had demonstrable, clinical, radiological and pathological findings of tumoral calcinosis was evaluated. The purposes were to compare the efficacy of bone scintiscans with serum phosphorus determination in detecting subclinical disease early in asymptomatic siblings and to assess therapeutic results in affected family members following initiation of phosphate depletion therapy. History, physical examination, serum calcium, serum phosphorus and bone scintiscans were performed in 12 of 13 siblings. All the affected siblings had markedly elevated serum phosphorus levels and abnormal bone scintiscans while the unaffected siblings had normal serum phosphorus levels and normal bone scintiscans. All the siblings, affected and unaffected, were normocalcaemic. After initiation of phosphate depletion therapy, gross changes in the appearance of lesions were detected on bone scintiscans. Serum phosphorus levels likewise showed a modest decline, although still remaining in the hyperphosphataemic range. In conclusion, bone scintiscans and serum phosphorus determinations are equally sensitive in detecting subclinical disease. However, the scintiscans are helpful in assessing not only the extent of the disease, but also whole-body and regional changes following any therapeutic interventions.

Adolescent↗