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At least 973 records · Page 54Linked to original sources
PubMed1997

Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain.

The non-invasive diagnosis of coronary artery disease in hypertensives with chest pain is an important clinical concern because all exercise-dependent tests display limited feasibility and diagnostic accuracy; by contrast, dipyridamole echocardiography testing has been shown to have a similar feasibility and accuracy in hypertensive and normotensive subjects. The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to 99mTc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease (>/=70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole 99mTc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole 99mTc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress.

Chest Pain↗
PubMed1997

Radioimmunoscintigraphy in patients with breast adenocarcinoma using technetium-99m labelled monoclonal antibody 170H.82: report of a phase II study.

Fifty-three women with clinical evidence of adenocarcinoma of the breast were studied with technetium-99m labelled monoclonal antibody (MAb) 170H.82 at protein doses of 1, 2 and 4 mg. An overall per lesion efficacy of 83.5% sensitivity and 97.7% positive predictive value was obtained. Efficacy appears higher in lesions restricted to the breast and local regional disease than systemic metastases. For the 2 mg dose the breast/local regional disease efficacy was 90% sensitivity and 90.2% positive predictive value. The biodistribution of this MAb was best represented by a two-compartment model with a distribution-phase half-life of 4.0+/-1.4 h, followed by an elimination-phase half-life of 39.6+/-6.6 h. In all six patients studied, the critical organ was the kidney, with a mean radiation absorbed dose of 37+/-6.9 mGy/GBq. The accuracy of this imaging technique allows the development of diagnostic strategies for the routine use of the compound in patients with breast cancer.

Adenocarcinoma↗
PubMed1995

Technetium-99m hexamethylpropylene amine oxime leucocyte scintigraphy for the diagnosis of bone and joint infections: a retrospective study in 116 patients.

The aim of this study was to evaluate the diagnostic value of technetium-99m hexamethylpropylene amine oxime leucocyte scintigraphy (HMPAO-LS) by means of a retrospective review of 116 patients divided into three groups of bone and joint infection. One hundred and thirty-one LS examinations were performed, and 143 sites analysed. The final diagnosis of infection was based on surgical, histological and bacteriological data and follow-up. Ninety-four suspected localizations were examined in group 1, which included 74 patients with an infection suspected to involve orthopaedic implants. In this group, there were 38 true-positives, 1 false-negative, 49 true-negatives and 6 false-positives. Surgical confirmation was obtained in 34 cases. In group 2 (24 patients with suspected osteomyelitis), there were 27 localizations of which 14 were true-positives and 13 were true-negatives (including seven surgical confirmations). In group 3 (18 patients suspected of septic arthritis) there were eight true-positives, two false-negatives, ten true-negatives and two false-positives. Overall sensitivity of 99mTc-HMPAO-LS for the detection of bone and joint infection was 95%, with a specificity of 90% (group 1: sensitivity 97%, specificity 89%; group 2: 100% and 100%; group 3: 80% and 83%). It may be concluded that HMPAO-LS is an effective tool for the diagnosis of both bone infection involving implants and chronic osteomyelitis.

Arthritis, Infectious↗
PubMed1995

Technetium-99m and indium-111 double labelling of granulocytes for kinetic and clinical studies.

A new technique of labelling granulocytes with both technetium-99m hexamethylpropylene amine oxime (HMPAO) and indium-111 in a single protocol was developed in order to exploit the advantages of each radiolabel in clinical and investigative studies. Fourteen patients were included in this prospective study. Granulocytes were labelled with both 111In-tropolonate and 99mTc-HMPAO. In vitro shape change assay and in vivo distribution and recovery studies were performed to assess the activation of and damage to these cells due to the labelling procedure. The comparative kinetics of 111In and 99mTc in the blood, liver, spleen, and bone marrow were studied by blood sampling and dual radionuclide imaging early (1 h) and late (24 h) after injection. The functional integrity of the double-labelled granulocytes and the feasibility of the technique were investigated in 14 patients with a painful prosthetic hip due to causes other than infection. The efficiency of double labelling was 63% (SD 14%) for 111In and 39% (SD 12%) for 99mTc-HMPAO. In vitro granulocyte activation and ex vivo recovery values were comparable to those from single radionuclide labelling. No artefactual granulocyte sequestration was seen in the lungs or liver. The radioactivity was distributed between the liver, spleen and bone marrow and, to a lesser extent, the lung. Early 99mTc counts in the liver, spleen and bone marrow, in relation to background, were significantly higher than 111In counts while the reverse was seen in late images.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Measurement of the ratio of glomerular filtration rate to plasma volume from the technetium-99m diethylene triamine pentaacetic acid renogram: comparison with glomerular filtration rate in relation to extracellular fluid volume.

Individual kidney glomerular filtration rate (IKGFR) can be measured from the renogram from the rate of uptake of technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA). A blood sample is required to derive IKGFR in millilitres per minute, which is then usually normalised to body surface area. We describe a technique which does not require a blood sample, is already normalised for plasma volume and uses the robust Patlak plot for measuring renal uptake. The rate of kidney uptake, dR(t)/dt, at time = 0, as a fraction of the injected dose, is equal to the fraction of the plasma volume (PV) filtered per minute, i.e. IKGFR/PV. The gradient dR(0)/dt cannot be accurately measured directly but is equal to [alpha .LV(0)], where alpha is the renal uptake constant (proportional to IKGFR) and LV is the count rate over a left ventricular ROI. LV(0) was obtained by extrapolation of LV(t), while alpha is the slope of the Patlak plot up to 3 min. GFR/PV (i.e. right plus left kidneys) in patients with normal renal function was about 0.04 min-1, as would be expected from normal values of GFR (120 ml/min) and plasma volume (3 l). GFR/PV correlated significantly with the ratio of GFR to extracellular fluid volume (ECV), measured from the terminal exponential of the plasma clearance curve (GFR/PV = 3.2.GFR/ECV + 5.3 ml/min/l [r = 0.82, n = 82]). GFR/PV (r = 0.74) and GFR/ECV (r = 0.82) both correlated inversely and non-linearly with plasma creatinine in 43 studies where the measurement was made within 1 week of the 99mTe-DTPA study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Review of imaging techniques for the diagnosis of breast cancer: a new role of prone scintimammography using technetium-99m sestamibi.

Imaging techniques currently used for the diagnosis of breast cancer are reviewed and compared. Besides mammography, magnetic resonance imaging, positron emission tomography, and thallium-201 scintimammography, a new role of technetium-99m sestamibi scintimammography is discussed. It is concluded that while mammography remains the procedure of choice in screening asymptomatic women for breast cancer, other imaging methods play an important role in detecting malignancies in symptomatic patients. 99mTc-sestamibi scintimammography has high sensitivity and improves the specificity of conventional mammography for the detection of breast cancer; with this technique, prone imaging is preferable to supine imaging. 99mTc-sestamibi scintimammography thus deserves further study as a screening technique.

Adult↗
PubMed1991

Technetium 99m mercaptoacetyltriglycine gamma camera clearance calculations: methodological problems.

Major sources of errors in the gamma-camera methods for the calculation of renal clearance are the accuracy of background correction for obtaining the true renal time-activity curve and the validity of the externally recorded pre-cordial activity as an estimate of the plasmatic time-activity curve. With technetium 99m mercaptoacetyltriglycine (99mTc-MAG3), because of its high protein plasma binding, one could expect minimal extravascular diffusion and hence a more accurate externally detected plasmatic curve. The high extraction rate should reduce the influence of the background, but, on the other hand, the effect of hepatobiliary excretion on the calculation of renal clearance might be significant. Our results suggest that the hepatobiliary excretion of 99mTc-MAG3 does not influence the gamma-camera renal clearance determination, even in patients with low renal function. However, the pre-cordial curve does not reflect accurately the plasmatic disappearance curve; its calibration with a single plasma sample taken at the 20th min is responsible for significant errors, probably because of an unfavourable ratio between the intravascular and extravascular activities at the 20th min.

Adult↗
PubMed1991

Perioperative myocardial perfusion scintigraphy at rest with technetium 99m methoxyisobutylisonitrile before and after coronary bypass operations.

Eighteen patients were examined at rest by technetium 99m methoxyisobutylisonitrile (99mTc-MIBI) myocardial scintigraphy 1 day before and 1 week after aorto-coronary bypass operation with planar and single photon emission tomography (SPET) imaging. One day postoperatively, a planar scintigraph in the intensive care unit (ICU) was done. Inter-observer variability was 3.8% for all examinations and for SPET alone, 3.9%. The quality of the planar images taken under emergency conditions in the ICU was quite comparable with those taken under routine conditions. The postoperative myocardial infarction in a patient who died 6 days later could clearly be demonstrated. In 16.2% of all segments which were hypoperfused at rest on preoperative scintigraphy, an amelioration of perfusion could be shown in the 1st week after the bypass operation. 99mTc-MIBI proved to be a useful agent to assess perioperative perfusion, in the ICU as well as under standard conditions.

Adult↗
PubMed1991

Measurement of synovial inflammation in rheumatoid arthritis with technetium 99m labelled human polyclonal immunoglobulin G.

The ability of technetium 99m labelled nonspecific, polyclonal human immunoglobulin G (99mTc-IgG) scintigraphy to depict and quantify synovial inflammation was studied in patients with rheumatoid arthritis (RA). Eight patients with clinically active synovitis were injected with 350 MBq 99mTc-IgG, and imaging took place 4 h later. This resulted in excellent images of inflamed synovium. Significant correlations were observed between individual joint uptake on the scan and scores for joint pain (n = 316, p less than 0.001), joint swelling (n = 300, p less than 0.001) or the average of pain and swelling (n = 300, p less than 0.001). These results suggest that 99mTc-IgG scintigraphy may provide an objective, non-invasive test to detect and measure synovitis.

Arthritis, Rheumatoid↗
PubMed1978

Extraosseous tumor uptake of 99m technetium phosphate compounds in children with abdominal neuroblastoma.

Sixteen patients with abdominal neuroblastoma had 99m Technetium Phosphate Compounds (99m TC-PC) bone scans as a preoperative evaluation for metastatic disease. Ten patients (62%) had extraosseous tumor uptake while six patients (38%) did not. There was no difference in the incidence of tumor calcification, tumor necrosis or hydronephrosis in the two groups. However, VMA levels were significantly higher in the group with extraosseous tumor uptake. Various bone seeking radionuclides are compared to 99m TC-PC and possible mechanism for extraosseous uptake of such radionuclides are postulated. Awareness of the frequency of such uptake should reduce the possibility of errors in the interpretation of bone scans in patients with neuroblastoma.

Abdominal Neoplasms↗
PubMed1995

Immunolocalization of transitional cell carcinoma of the bladder with intravesically administered technetium-99m labelled HMFG1 monoclonal antibody.

The aim of this study was the immunolocalization of transitional cell carcinoma of the bladder with a radiolabelled murine tumour-associated monoclonal antibody and the measurement of the absolute uptake of the antibody by the tumour. Fourteen patients with transitional cell carcinoma of the bladder received 3-6 mCi (111-222 MBq) of technetium-99m labelled HMFG1 monoclonal antibody intravesically and one patient, 2 mCi (74 MBq) of iodine-131 labelled 11.4.1, which is a non-tumour-specific monoclonal antibody. Four of the 15 patients were evaluated with single-photon emission tomography (SPET) 1 1/2 to 2 h post administration. All patients underwent transurethral resection of the bladder tumour within 12-20 h following intravesical administration of the radiolabelled antibody. The radioactivity of biopsy specimens from normal urothelium and tumour areas were counted in a gamma counter. The mean uptake of the radiolabelled antibodies from normal and tumour sites was expressed as a percentage of the administered dose per kilogram of tissue. Conventional histology and immunohistochemistry using HMFG1 monoclonal antibody were performed on paraffin sections of the biopsy specimens. Although our results are preliminary, it can be concluded that: (a) bladder tumours are well imaged by SPET when using 99mTc-HMFG1; (b) intravesically administered radiolabelled antibody remains on the bladder tissue and does not escape into the systemic circulation; (c) the wide range of tumour uptake values (0%-9.3% administered dose/kg) observed probably can be attributed to heterogeneity of the antigenic expression of the tumour; (d) values of 99mTc-HMFG1 monoclonal antibody uptake by the tumour do not justify future attempts at radioimmunotherapy.

Administration, Intravesical↗
PubMed1995

Exercise gated planar myocardial perfusion imaging using technetium-99m sestamibi for the diagnosis of coronary artery disease: an alternative to exercise tomographic imaging.

Single-photon emission tomography (SPET) using technetium-99m labelled myocardial tracers (e.g. 99mTc-sestamibi) has become one of the most popular myocardial imaging methods for the diagnosis of coronary artery disease (CAD). This prospective study was designed to evaluate the diagnostic performance of 99mTc-sestamibi exercise gated planar myocardial imaging by comparison with both visual and quantitative analyses of SPET. The study was conducted in 115 consecutive patients with known or suspected CAD, including 54 patients with a previous myocardial infarction (MI), referred for exercise testing prior to coronary angiography. Multi-gated planar imaging and SPET were performed after bicycle exercise. The end-diastolic (ED) and SPET images were visually scored (SVi). Myocardial uptake was quantitated on SPET slices using maximum count circumferential profiles (SQu) and defect extent was measured by comparison with gender-matched data sets obtained from 27 controls (< 5% likelihood of CAD). CAD was defined as coronary artery stenosis > 50% and/or regional wall motion abnormality. The cut-off criteria for positivity of the three procedures were determined from receiver operating characteristic (ROC) curves derived from the data of patients without previous MI. The area under the ROC curves was similar for ED, SVi and SQu. This was confirmed by the analysis of sensitivity performed using the ROC curve-derived cut-off criteria, in patients with or without previous MI. SVi was more sensitive than ED in identifying the diseased vessel(s) (ED: 41% vs SVi: 80%; P < 0.0005) but ED was more specific in this respect (ED: 79% vs SVi: 61%; P < 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Quantitative assessment of technetium-99m methoxyisobutylisonitrile planar perfusion heart studies: application of multivariate analysis to patient classification.

A quantified evaluation of planar cardiac perfusion scintigrams (the objective of the study), obtained using technetium-99m methoxyisobutylisonitrile (MIBI) was performed on the basis of an analysis of circumferential profile curves, representing the perfusion as seen in three typical projections. The analysis involved the curves obtained both at rest and after stress, and was based on a comparison of their shape (trend) with the normal trend (normative evaluation). The latter was obtained by means of an original method of iterative fitting of individual curves into the database. The base consisted of curves recorded in 53 patients (separately in males and females) with normal perfusion of the left ventricle (group I, the reference group). A group of 90 patients suspected of having coronary artery disease (group II) was subdivided into two subgroups on the basis of coronary arteriography: (a) those with and (b) those without critical stenosis of at least one artery. Profile curves characterising the LV perfusion were obtained at rest and after stress. Defects of perfusion were quantified by comparison of individual curves with the normal trends. By means of multivariate analysis it was demonstrated that vectors of mean values characterising the scintigraphically assessed defects of LV perfusion in the two subgroups of group II differed very significantly (P < 10(-5)). Applying methods of discriminant analysis, a classification of patients from group II was performed into those with probable defects of perfusion and those free of such defects. The sensitivity, specificity and accuracy of diagnosis of coronary ischaemia, based on quantified planar 99mTc-MIBI scintigraphy, reached 86%, 87% and 87%, respectively.

Adult↗
PubMed1996

Scintimammography with technetium-99m methoxyisobutylisonitrile: comparison with mammography and magnetic resonance imaging.

The aim of the study was to compare the diagnostic accuracy of scintimammography with technetium-99m methoxyisobutylisonitrile (MIBI; SMM) in the detection of primary breast cancer with that of mammography (MM) and magnetic resonance imaging (MRI). Fifty-six patients with suspected lesions detected by palpation or MM were included in the study. Within the 4 weeks preceding excisional biopsy, MM and MRI were performed in all patients. Between 5 and 10 min after the injection of 740 MBq 99mTc-MIBI, SMM in the prone position was performed. In the total group of 56 patients, 43 lesions were palpable, while 13 were non-palpable but were detected by MM. Breast cancer was confirmed by histopathology in 27 of the patients (22 palpable and 5 non-palpable carcinomas). The tumour size ranged from 6 to 80 mm in diameter. For non-palpable lesions, the sensitivity of SMM, MM and MRI was 60%, 60% and 100%, respectively, while the specificity was 75%, 25% and 50%, respectively. For palpable breast lesions, all methods showed high sensitivity (SMM 91%, MM 95%, MRI 91%) but SMM demonstrated significantly higher specificity (SMM 62%, MM 10%, MRI 15%). In two mammographically negative tumours (dense tissue), SMM showed a positive result. In comparison to MRI, one additional carcinoma could be diagnosed by SMM. It may be concluded that for palpable breast lesions, the diagnostic accuracy of SMM is superior to that of MM and MRI. Through the complementary use of SMM it is possible to increase the sensitivity for the detection of breast cancer and multicentric disease. In patients in whom the status of a palpable breast mass remains unclear, SMM may help to reduce the amount of unnecessary biopsies.

Biopsy↗
PubMed1996

Primary breast cancer imaging with technetium-99m sestamibi and its relation with P-glycoprotein overexpression.

The aim of this preliminary study was to evaluate retrospectively sestamibi scintigraphy in relation to the presence of the 170-kDa P-glycoprotein (Pgp), which represents an expression of multidrug resistance in patients with primary breast cancer. Fifteen women (age range 37-76 years) were referred for technetium-99m sestamibi scintigraphy because of suspicious breast lesions detected by mammography and ultrasonography, and subsequently assessed by fine-needle aspiration. Scintigraphy was performed 30 min following the injection of 500 MBq 99mTc-sestamibi. Three planar anterior and oblique images were obtained with the patient in the supine position. Excised tumours were assessed for cytosolic CA 15.3, oestrogen (OR) and progesterone (PR) receptors and c-erb B2 neu oncogene. Pathology revealed that only 13 of the 15 patients had malignant tumours. The two benign tumours were sestamibi-negative and Pgp-positive. Sestamibi scintigraphy was positive in 10 of the 13 malignant lesions (including nine of ten infiltrating ductal carcinomas). Two of the three lesions with false-negative scintigraphy were Pgp-negative; in one of these cases histology revealed an invasive lobular carcinoma and in the other, mucinous adenocarcinoma. The third false-negative lesion was a Pgp-positive infiltrating ductal carcinoma which was c-erb B2 neu-negative but CA 15.3-, OR- and PR-positive. This preliminary study confirms that the resistance to chemotherapy which may occur in patients with primary breast cancer can be a cause of negative sestamibi scintigraphy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Technetium-labeled myocardial imaging agents.

99mTc sestamibi and 99mTc teboroxime has unique features that differ from thallium-201 in dosimetry, energy, cellular transport, extraction fraction, retention, washout, and imaging protocols. Sestamibi is ideal for gated and SPECT imaging while SPECT imaging with a multi-head detector system is preferred for teboroxime. Both permit simultaneous assessment of perfusion and function using first-pass radionuclide angiography. This paper discusses the special features and clinical applications of these two technetium agents.

Coronary Disease↗
PubMed1997

Comparison technetium of Tc-99m disofenin cholescintigraphy with ultrasonography in the differentiation of biliary atresia from other forms of neonatal jaundice.

Technetium Tc-99m disofenin cholescintigraphy (CS) and ultrasonography (US) are two major clinical methods used in differentiating biliary atresia (BA) from neonatal jaundice. To compare the diagnostic utility of these two modalities, 66 patients with neonatal cholestasis (15 BA, 3 choledochal cyst (CC), 32 neonatal hepatitis, 13 prolonged jaundice, 2 total parenteral nutrition, and 1 sepsis) underwent Tc-99m disofenin CS and US. The diagnostic sensitivity, specificity, and accuracy of CS in differentiating BA from other forms of neonatal jaundice was 100%, 87.5%, and 90.5%, respectively, and for US 86.7%, 77.1%, and 79.4%, respectively. Tc-99m disofenin CS after premedication with phenobarbital and cholestyramine is a convenient and reliable method of differentiating BA from neonatal hepatitis, with a diagnostic accuracy superior to that of US. However, US is the initial imaging procedure of choice in patients presenting with jaundice to rule out anatomic anomalies such as CC.

Biliary Atresia↗
PubMed1996

Technetium-99m tetrofosmin imaging in thyroid diseases: comparison with Tc-99m-pertechnetate, thallium-201 and Tc-99m-methoxyisobutylisonitrile scans.

Technetium-99m tetrofosmin is a lipophilic phosphine used for myocardial perfusion imaging. Biodistribution studies have shown significant thyroid uptake of tetrofosmin and preliminary reports have suggested that tetrofosmin imaging may be of value in patients with thyroid cancer. In this study, tetrofosmin whole-body scintigraphy was performed in 35 patients with evidence of thyroid diseases. All patients underwent laboratory evaluation of thyroid function as well as 99mTc pertechnetate scan, thallium-201 (n=16) 99mTc-methoxyisobutylisonitrile (MIBI) (n=19) whole-body studies. Thyroid images were semi-quantitatively analysed by a 4-point score: 0=no significant uptake; 1=uptake increased as compared to background activity, but inferior to normal thyroid tissue; 2=uptake equal to normal thyroid tissue; 3=uptake superior to normal thyroid tissue. Pathology examinations were obtained. A total of 41 thyroid nodules were detected, of which 15 were goitre nodules, 13 adenomas and 13 malignant lesions. In goitre nodules, concordant results of tetrofosmin and pertechnetate uptake (score 1 or 0) were observed in the majority of lesions (87%). In function adenomas (n=10), both tetrofosmin uptake and pertechnetate uptake were score 3. In non-function adenomas (n=3), tetrofosmin uptake was score 3, while pertechnetate uptake was score 0. In six malignant lesions, tetrofosmin uptake was score 3, while pertechnetate uptake was score 0; in the other seven lesions, where a prevalence of goitre abnormalities was observed, results of tetrofosmin and pertechnetate uptake were similar (score 0 or 1). In seven (70%) of the ten patients with malignant nodules, whole-body tetrofosmin images showed increased abnormal uptake in a total of 28 extra-thyroid tumour sites, as subsequently confirmed by other techniques. When tetrofosmin images were compared to 201Tl and 99mTc-MIBI scans, concordant results were observed in all cases. In conclusion, tetrofosmin imaging may be particularly useful to characterize and stage patients with malignant thyroid nodules; it shows similar results to thallium but provides better image quality. Comparable findings were observed between tetrofosmin and MIBI studies. Thus, tetrofosmin may be an alternative to thallium and MIBI in the aforementioned patients.

Adenoma↗