PubMed Health⌕ Search

Biomedical subjects

F X Sundram

Publications and source records attributed to F X Sundram.

At least 37 records · Page 2Linked to original sources
PubMed1996

Radionuclide imaging in primary hyperparathyroidism using 99mTc sestamibi--four case reports.

Radionuclide imaging using the 99mTc sestamibi either singly or as a subtraction technique with pertechnetate is a recent and reliable method in localising parathyroid adenomas prior to surgery. This is of use in pre-operative planning, as well as in failed first neck exploration. Four local patients with primary hyperparathyroidism whose parathyroid adenomas were localised by this scintigraphy are presented. The value and limitations of this imaging modality are discussed.

Adult↗
PubMed1995

Clinical studies of alveolar-capillary permeability using technetium-99m DTPA aerosol.

Soluble radioaerosols such as technetium-99m diethylene triamine pentacetate (DTPA) permit simple quantitative studies of alveolar-capillary permeability to be performed, since the submicronic aerosols are deposited mainly at the lung periphery and are cleared across the alveolar-capillary membrane. Regional alterations in permeability can also be noted using this radionuclide technique. We have measured the pulmonary epithelial permeability in normal subjects and the alteration in smokers, in glue-sniffers, in patients with inhalation burns, in chronic obstructive pulmonary disease (COPD) and in patients with lung metastases from thyroid cancer treated with radioiodine 131I. In the normal volunteers, the time taken for 50% of inhaled 99mTcDTPA to be cleared form the lungs (T1/2) was 66 minutes +/- 1sd of 12 mins. The smokers had a mean T1/2 of 20 mins +/- 1sd 4 min. In the hard-core glue-sniffing group, the majority were smokers who had stopped smoking and glue-sniffing for periods varying from 1 day to 42 days, and it was possible to note the changes in clearance times against period of abstinence. In the patients with inhalations burns, there was change in lung clearance arising from pulmonary epithelial damage; these patients showed increased rate of clearance (short T1/2) with mean T1/2 of 36 min +/- 1sd of 11 mins, while the retention images revealed regional lung damage in moderately severe inhalation burns. Twenty-four patients with COPD had inhalation scans done with Tc-99m tin colloid radioaerosol, and these images were compared with the perfusion lung scans done with 99mTc macroaggregated albumin (MAA); in general the perfusion images matched the defects noted in the inhalation scans. The 99mTc DTPA clearance rate in these patients was normal i.e. T 1/2 = 78 +/- 14 mins. In the thyroid cancer patients with lung metastases, who had high doses of radioiodine treatment, the T 1/2 values were normal or prolonged slightly, mean T1/2 = 76 min +/- 23.

Adolescent↗
PubMed1995

Thyrotropin with decreased biological activity, a delayed consequence of cranial irradiation for nasopharyngeal carcinoma.

Patients with TSH of decreased bioactivity have had previous surgery or no known cause (idiopathic). We describe eight patients with nasopharyngeal carcinoma treated with irradiation alone more than 5 yr ago. All had hypothalamic hypothyroidism with low FT4 and normal TSH. Iv TRH gave an exaggerated TSH response, with 60 min greater than 20 min values, without any FT4 or TT3 response at 24 h to the hypersecreted TSH. Radioiodine uptake in 2 patients before and after 3 days of bovine TSH increased from 13 to 31%, and 11 to 28%, respectively. Oral TRH given for 20 days to 5 patients showed a distinctive pattern in serum TSH, FT4 and TT3. Serum TSH rose markedly in the initial few days, dropped to moderate levels for a few days and finally dropped further towards normal values. In contrast, the FT4 and TT3 remained unchanged at hypothyroid levels in the first few days, despite the very elevated TSH; but increased to euthyroid levels and remained higher even while the serum TSH declined further. Direct measurement of TSH bioactivity in FRTL-5 cells in 3 patients showed low values of bioactivity to immunoactivity ratios: 0.4, < 0.2, and 0.35 (NR 0.6-2.1) which increased in 2 patients to 0.9 and 0.8 after 20 days TRH. Serum free alpha-subunit levels were low and unchanged (0.3 to 1.1 micrograms/L) with prolonged TRH. These observations suggest that cranial irradiation may cause hypothalamic hypothyroidism with TSH with decreased bioactivity, and that prolonged TRH administration may restore normal bioactivity.

Adult↗
PubMed1995

Evaluation of thyroid nodules for malignancy using 99Tcm-sestamibi.

99Tcm-sestamibi (99Tcm-MIBI) is used for myocardial perfusion imaging but has also been reported to localize in tumours. The usual thyroid scanning radionuclide is 99Tcm-pertechnetate. Altogether, 161 patients with clinically solitary thyroid nodules had both 99Tcm-MIBI and 99Tcm-pertechnetate thyroid scans, with the nodules being reported as cold, warm or hot. Fine-needle aspiration cytology (FNAC) and surgery were performed in those patients who consented to these procedures. Of 131 patients who had FNAC, only 58 proceeded to surgery. In the surgically treated group, 14 of 58 (24%) were confirmed to have thyroid cancer, whereas 44 of 58 (76%) had benign lesions. The 14 cancerous nodules were cold on the 99Tcm-pertechnetate scan, whereas with 99Tcm-MIBI 11 were warm and 3 were either cold or hot nodules. Of the 44 benign lesions, 18 were cold, 9 were warm and 17 were hot nodules. In those 131 patients who had FNAC, the cytology was reported as benign in 120 of the nodules and malignant in 11. The three false-negative cytologies were reported as follicular adenomas. The benign lesions noted on FNAC and surgery were thyroiditis, adenomas and haemorrhagic or colloid cysts. The results from the 58 surgically treated patients suggest that the warm nodules would need surgery, whereas the cold and hot nodules are unlikely to be malignant. The overall sensitivity of the 99Tcm-MIBI scan was 79% and the specificity 80%, with the warm nodule on 99Tcm-MIBI scan having a positive predictive value of 55% and a negative predictive value of 92%.

Adenocarcinoma, Follicular↗
PubMed1995

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease.

Technetium-99m hexakis-2-methoxy-isobutyl-isonitrile (99mTc sestamibi) has been used for myocardial perfusion imaging in the evaluation of coronary artery disease (CAD) since 1990. The experience of its use in an Asian population with and without previous myocardial infarction (MI), diabetes mellitus (DM), hypertension (HPT) and collateral circulation (COL) is reported. One hundred and thirty-nine patients who underwent treadmill exercise testing with 99mTc sestamibi single photon emission computed tomography (SPECT) and coronary angiogram were studied. The overall sensitivity for the detection of CAD was 91.0% and specificity was 64.7%. For patient without previous myocardial infarction, the sensitivity was 83.8% and specificity was 83.3%. Patients with COL had a higher sensitivity while those with HPT had a lower specificity. Sensitivity was higher in patients with multi-vessel disease (MVD) than single vessel disease (SVD). The overall detection for individual artery stenosis was 74.1% with a specificity of 73.1%. Amongst the three major coronary arteries, sensitivity was highest for the right coronary artery and specificity was highest for the left circumflex artery. Specificity was higher in patients without MI or COL. We found that the agreement between 99mTc sestamibi SPECT and coronary angiogram for the extent of CAD was only 52.5%. The concordance rate was higher for patients with MVD than SVD. It is concluded that 99mTc sestamibi SPECT is a sensitive and specific test for the detection of CAD and localization of disease to individual coronary arteries in our patients with some differences in the subgroups. Agreement between coronary angiogram and 99mTc sestamibi for the extent of coronary artery disease was also satisfactory.

Adult↗
PubMed1995

Effect of lithium and oral thyrotrophin-releasing hormone (TRH) on serum thyrotrophin (TSH) and radioiodine uptake in patients with well differentiated thyroid carcinoma.

Oral thyrotrophin-releasing hormone (TRH) and lithium were given to patients on follow-up for well-differentiated thyroid carcinoma to see their effect on serum thyrotrophin level (TSH) and radioiodine (I-131) uptake (RAIU). The study was randomised and doubled-blinded and consisted of a total of 19 patients in 3 groups. Group 1 received placebo and TRH, group 2 received lithium and placebo, and group 3 received lithium and TRH. Serum TSH and RAIU at 24 hours were measured before, and after treatment, with TRH, lithium, and/or placebo. In group 1, mean (+/-SEM) TSH increased from 48.9 (+/-15.2) mU/l to 148.2 (+/-48.0) mU/l (p < 0.05); in group 2, the change of 24.9 (+/- 15.9) mU/l to 31.7 (+/-14.1) mU/l in TSH was not statistically significant; and in group 3, TSH increased from 108.1 (+/-13.8) mU/l to 187.0 (+/-39.1) mU/l (p < 0.05). However, despite the significant change in TSH, there was no significant increase in I-131 uptake in any group: 7.70% to 10.43%, 7.15% to 7.43% and 2.49% to 2.61%, in groups 1, 2 and 3 respectively (p > 0.05). We conclude that while oral TRH will increase endogenous serum TSH significantly, there is no significant increase in I-131 uptake. Lithium was not an useful adjunct in increasing serum TSH or I-131 uptake in these patients.

Adenocarcinoma, Follicular↗
PubMed1995

Technetium-99m (Tc-99m) diphosphono-propanedicarboxylic acid bone tracer uptake and Tc-99m sestamibi distribution in cardiac amyloidosis--a case report.

It has long been recognised that significant bone tracer localisation in the myocardium is a good indicator for amyloid involvement of the heart in the clinical context of systemic amyloidosis. In this case report, although myocardial tissue diagnosis of amyloidosis was not made, the massive myocardial uptake of bone tracer strongly suggested the presence of amyloid infiltration in the heart, and this finding eventually led to the histological diagnosis of familial amyloid polyneuropathy by skin and sural nerve biopsy. Interesting findings were noted in the single photon emission computerised tomography (SPECT) studies of the myocardium with Technetium-99m diphosphono-propanedicarboxylic acid bone agent and Technetium-99m sestamibi myocardial perfusion agent. Such findings suggest that there is a lack of correlation between the intensity of myocardial uptake of bone tracer and viability of the myocardium, and that amyloid will not deposit in infarcted myocardial tissue.

Amyloid Neuropathies↗
PubMed1994

Radionuclide detection of dialysate leakage in patients on continuous ambulatory peritoneal dialysis.

While continuous ambulatory peritoneal dialysis (CAPD) offers several advantages over haemodialysis in patients with end-stage renal disease, several complications have been recognised. The intraperitoneal instillation of dialysate increases intra-abdominal pressure and consequently predisposes to leaks and herniations through defects in the abdominal wall. This can lead to disruption of CAPD therapy. Peritoneal scintigraphy with Tc99m colloid has been used to identify such leaks of dialysate. This report analyses the clinical role of peritoneal scintigraphy in patients on the CAPD programme in the Singapore General Hospital. The results of 25 scans performed over a two-and-a-half year period were correlated with clinical and surgical findings. The clinical presentations of suspected dialysate leakage were varied, but can be broadly classified into three subsets for this analysis: (A) swellings confined to the inguinal and genital region, (B) peri-catheter, umbilical and incisional swellings, and (C) diffuse pattern of swellings in the abdominal wall, pelvic and genital region. In group A, the scan proved to be clearly helpful, correctly identifying 10/10 inguinal hernias, all of which resolved after herniorrhaphy. In group B, the scan correctly identified 7/9 leaks and hernias in the ventral abdominal wall. There was one false negative scan in a patient with a peri-catheter leak, and an equivocal result in another with fluid leakage in the lower anterior abdominal wall. In group C, which presented the greatest difficulty in clinical diagnosis, 2/3 cases were correctly diagnosed by scintigraphy. An equivocal result was seen in a patient who had had multiple operations for recurrent incisional hernias.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1993

99Tcm-polyclonal IgG and 99Tcm nanocolloid scans in orthopaedics: a comparison with conventional bone scan.

The bone scan is sensitive in detection of active bone/joint lesions. A normal bone scan virtually excludes the presence of an inflammatory process with high precision, but the poor specificity of bone scans is well known. In recent years, various new agents including 99Tcm-hexamethylpropylene amine oxime (HMPAO)-labelled white blood cells, nanocolloid, polyclonal IgG, anti-granulocyte antibody, 111In-labelled IgG, leucocytes, chemotactic peptides etc. have been widely evaluated in inflammatory imaging, especially in the orthopaedic context. This study was undertaken to compare the usefulness of 99Tcm-nanocolloid and 99Tcm-polyclonal IgG in the detection of focal bone/joint inflammation. Twenty-seven patients with a common presentation of bone/joint pain resulting from various pathologies were included in the study. A total of 47 lesions were imaged. The overall sensitivity and specificity of both nanocolloid scan and IgG scan were identical with 95% sensitivity and 100% specificity, in detecting inflammatory foci. However, specificity dropped to 18% with nanocolloid scans and 16% with IgG scans when an attempt was made to distinguish noninfective from infective inflammatory processes; thus neither type of scan permits differentiation between septic and nonseptic inflammatory processes with sufficient accuracy. As both nanocolloid and IgG scans are equally sensitive and specific in detecting inflammation, the choice of type of scan will depend on cost, imaging time and availability of the radiopharmaceutical.

Adolescent↗
PubMed1993

Role of technetium-99m sestamibi in localisation of thyroid cancer metastases.

Technetium-99m sestamibi (MIBI) is a routinely used myocardial perfusion imaging agent. We have studied groups of patients with differentiated thyroid carcinoma, in order to evaluate the usefulness of this agent in localising regional neck and nodal disease and metastases. There are three groups of patients. Group 1 consisted of patients with known nodal disease or metastases (22 patients) and with raised serum thyroglobulin levels (Tg). Group 2 comprised patients with normal I-131 scans and normal Tg levels (nine patients). Non-thyroid malignancies (six patients) comprised an additional group 3. In group 1, the MIBI scan showed 47 sites of metastases, while the I-131 scan revealed 49 sites. The MIBI scan was positive in two patients where the I-131 scan was negative, while in two other patients, the MIBI study was negative whereas the I-131 scan was positive. In group 2, 6/9 patients had no disease, 2/9 had thyroid remnants, and 1/9 had a fresh primary lung tumour, unrelated to the earlier thyroid cancer. All of them had normal MIBI scans. In group 3, two patients with lung cancer and two with breast cancer and metastases had normal MIBI scans. A further two patients with nasopharyngeal cancer (NPC) had mildly increased MIBI localisation in neck nodes and bone metastases. In summary, Tc-99m sestamibi appears to be as good as I-131 in search for thyroid carcinoma metastatic spread, especially nodal disease and this tracer does not localise well in the primary or metastases of other cancers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma, Follicular↗
PubMed1993

Prospects for tumour imaging with radiolabelled antibodies.

An ideal diagnostic imaging method in cancer management should be one which surveys the entire body for occult or small tumour foci in a single procedure. Imaging with radiolabelled antibodies appears to have such potential if the limiting factors which we have encountered in the last 40 years can be completely eliminated. These factors include antibody-dependent factors, radionuclide-dependent factors, host-dependent factors and imaging modality-dependent factors. Advances in immunology and bio-genetic engineering have enabled production of various antibody fragments and genetically engineered antibody molecules (i.e. chimeric/humanized antibodies and the single-chain antigen binding protein), giving a promise of overcoming the problem of cross-reactivity and host immuno-response. The rapid development in radiopharmacy and labelling chemistry has led to the establishment of various pre-targetted methods which are aimed to improve the tumour to non-tumour ratio. The recent success of producing Tc99m labelled monoclonal antibodies preparation in a kit form has certainly encouraged its clinical applications and made antibody imaging a less tedious task. The progression in computer technology has made "image fusion" possible and hence improve the accuracy of anatomical localization of tumour foci in antibody imaging. It would appear possible to overcome most, if not all, of the limiting factors mentioned above in the near future. The prospect of radiolabelled antibodies in tumour imaging is promising and the dream of a "magic bullet" will soon be fulfilled.

Humans↗
PubMed1992

Radionuclide lung scanning in the management of respiratory burns.

Soluble radioaerosols such as technetium-99m diethylene triamine pentacetate (DTPA) permit simple quantitative studies of alveolar-capillary permeability to be performed, since the submicronic aerosols are deposited mainly at the lung periphery and are cleared across the alveolar-capillary membrane. Regional alterations in permeability can also be noted using this radionuclide technique. We have measured the alteration in pulmonary epithelial permeability in normal subjects and in patients with inhalation burns using a computer-linked gamma-camera. In the normal volunteers, the time taken for 50% of inhaled Tc-99m DTPA to be cleared from the lungs (T1/2) was 66 minutes +/- 1sd of 12 minutes. In the 42 patients with inhalation burns, besides the T1/2, retention images of uncleared Tc-99m DTPA in the lungs were obtained to note regional differences, if any, in lung clearance arising from pulmonary epithelial damage; these patients showed increased rate of clearance (short T1/2) with mean T1/2 of 36 minutes +/- 1sd of 11 minutes, while the retention images revealed regional lung damage in moderately severe inhalation burns. In 18 patients with abnormal T1/2, 16 (89%) had abnormal bronchoscopy findings. Fifteen patients also had lung perfusion scans with Tc-99m MAA (macroaggregated albumin). The regional defects in perfusion when present were generally matched with the defects seen on ventilation scans. The Tc-99m DTPA lung clearance measurement and imaging has clinical usefulness in suspected inhalation burns.

Accidents, Occupational↗
PubMed1990

Bone scintigraphy in nasopharyngeal carcinoma.

One hundred and forty-three patients (Group 1) with histologically proven nasopharyngeal-carcinoma (NPC) had bone scintigraphy with 99Tcm methylenediphosphonate (MDP) or dihydroxypropanediphosphonate (DPD) within 2 months of the initial diagnosis. A further 162 patients (Group 2) had bone scans during the course of follow-up if there were symptoms of bone pain or evidence of metastases at other sites. Twenty-three per cent (33/143) of the newly diagnosed NPC patients (Group 1) had evidence of bone metastases. Of these 143 patients, 101 were T0-T2, 16 were T3 and 25 were T4. Thirty-six patients had no neck nodes (NO), 44 were N1, 25 N2 and 38 N3. Of the 162 patients in Group 2, 96 (59%) had a positive bone scan. The commonest sites for bony metastases from NPC were the spine, ribs, pelvis and lower limbs in order of frequency. There is a highly significant association with the nodal stage but no association with the UICC T staging which is not adequate in nasopharyngeal carcinoma. In our part of the world, bone metastases from NPC are a common cause of an abnormal bone scan.

Adolescent↗
PubMed1990

Remission of Ménétrier's disease associated with ranitidine administration.

We describe a patient with Ménétrier's disease in whom acute administration of ranitidine reduced gastric protein loss more effectively than cimetidine or propantheline. This patient went into remission following a course of ranitidine. We reviewed the literature on remissions in Ménétrier's disease occurring without surgery. More detailed studies of various anti-secretory agents on individual patients are required to determine whether or not they are truly efficacious.

Adult↗
PubMed1990

Use of radionuclides in clinical endocrinology.

Radionuclides provide sensitive reporter molecules for labeling pharmaceuticals. Hormone measurements using radioimmunoassays are commonplace today, increasing our understanding of the pathophysiology of endocrine disease. In turn, hormones tagged with radionuclides are opening studies on new fields of receptor defects both at the receptor site and beyond. Common disorders such as diabetes mellitus, hyperthyroidism and acromegaly have been the first to benefit. Tracer methods to study secretory and clearance rates and the size of metabolic pools are mainly based on the use of radionuclides. DNA probes are useful in unravelling endocrine defects at the genome level. Originally using radioiodine but now an increasing number of newly synthesised radiopharmaceuticals, the individual organs are being visualised more specifically. Among these agents are labelled monoclonal antibodies hunting for neoplasias and analogs of adrenal medullary hormones such as metaiodobenzylguanidine (MIBG). From these studies the therapy of endocrine disorders will ultimately benefit.

Adrenal Glands↗