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PubMed1987

An evaluation of the uptake of technetium-99m (v) dimercaptosuccinic acid in patients with squamous carcinoma of the head and neck.

A new imaging agent, Technetium-99m (Tc99m) (v) Dimercaptosuccinic acid (DMSA), has recently been developed which has been used to evaluate head and neck tumours. Twenty-four patients were studied of whom 21 had histologically proven SCC of the head and neck. The remaining 3 had benign lesions. Planar imaging of patients with primary disease revealed a sensitivity of 83% and a 75% specificity. The results of planar imaging of patients with cervical metastases yielded a 92% sensitivity and 100% specificity. Seven patients also had single photon emission computerized tomography (SPECT) which improved the image quality, spatial resolution and sensitivity of the investigation. Tc99m (v) DMSA imaging provides a cheap and rapid means of investigating head and neck SCC. This study suggests further work is indicated to assess its role in diagnosis and subsequent management.

Adult↗
PubMed1996

Usefulness of technetium-99m-galactosyl human serum albumin liver scintigraphy for assessment of severity of alcoholic hepatitis.

We performed a liver scintigraphy using technetium-99m diethylene-triaminepentaacetic acid-galactosyl human serum albumin (99mTc-GSA), which images the functional liver mass through its binding to the specific receptor asialoglycoprotein receptor in patients with severe alcoholic hepatitis. Receptor index (LHL 15) was significantly lower in patients with alcoholic hepatitis, compared with controls with normal liver. Difference in the isotope uptake patterns between liver and heart varied according to the severity of liver disease, and made it possible to categorize 5 grades. Grading score could discriminate between the eventual outcome of the patients. Furthermore, single photon emission computed tomography showed the variable uptake patterns in the hepatic lobule, wherein there were no evident findings in macroscopic view at autopsy. The results of this study show the usefulness of 99mTc-GSA scintigraphy in the evaluation and prognosis of alcoholic hepatitis.

Adult↗
PubMed2001

Functional hepatic volume measured by technetium-99m-galactosyl-human serum albumin liver scintigraphy: comparison between hepatocyte volume and liver volume by computed tomography.

OBJECTIVES: We investigated the usefulness of measuring the functional hepatic volume by single-photon emission CT with 99m-technetium galactosyl-human serum albumin scintigraphy (GSA-LV). We then compared this value to the total hepatocyte volume and the hepatic volume determined from CT (CT-LV) in the patients with hepatobiliary tumors. METHODS: Forty-seven patients were divided into two groups, the SM group (subsegmentectomy and monosegmentectomy) and the DT group (disegmentectomy and trisegmentectomy). These groups were further divided into subgroups with or without chronic hepatitis or cirrhosis. The GSA-LV, CT-LV, and the total hepatocyte volume were then calculated. The GSA-LV and CT-LV measurements were performed preoperatively, at 2 and 4 wk, and at 3 and 6 months after surgery. RESULTS: The preoperative GSA-LV values were significantly correlated with the hepatocyte volume and the 15-min retention rate of indocyanine green (ICGR15). Similarly, the hepatocyte volume correlated well with the CT-LV and ICGR15. However, the CT-LV was correlated only with the ICGR15. Recovery of the GSA-LV in the DT group was delayed, and about 90% of the volumetric and functional regeneration was observed within 6 months after the hepatectomy. In contrast, the CT-LV of DT group patients with normal liver remnants returned to approximately 90% of their initial volume within 1 month after the hepatectomy, whereas patients with injured livers regenerated gradually and regained approximately 80% of their preoperative value by 6 months after the hepatectomy. CONCLUSIONS: We conclude that the measurement of functional hepatic volume using the GSA-LV is useful in fully evaluating hepatic function based on hepatocyte volume.

Bile Duct Neoplasms↗
PubMed1985

Estimation of glomerular filtration rate in children using 99m-technetium DTPA. A comparison with 51-chromium EDTA clearance.

The usefulness of radionuclide imaging studies with 99m-technetium diethylenetriaminepentaacetic acid (Tc-DTPA) for quantitating the glomerular filtration rate (GFR) in children was studied. This was compared to the conventional methods for measuring GFR using 51-chromium-EDTA clearance (Cr-EDTA), creatinine clearance and a height/plasma creatinine formula. In the 22 children studied, the correlation coefficient between renal uptake of DTPA and Cr-EDTA was 0.90 (p less than 0.001). In contrast, there was a poorer correlation between Cr-EDTA and creatinine clearance (r = 0.69) or the derived GFR using height/creatinine formula (r = 0.83). The regression line between Tc-DTPA uptake and Cr-EDTA clearance was used to derive a formula for calculating the predicted GFR. This was tested in 10 additional children, and the correlation between the predicted GFR and measured GFR (using Cr-EDTA clearance studies) was 0.92 (p less than 0.001). Quantitative estimation of the GFR during renal imaging studies is a feasible and convenient method of assessing renal function.

Adolescent↗
PubMed1997

Technetium-99m labelled liposomes to image experimental arthritis.

OBJECTIVES: Liposomes sterically stabilised with polyethylene glycol (PEG) labelled with technetium-99m were tested for their ability to image adjuvant arthritis in a rat model. METHODS: Adjuvant arthritis was induced in the ankle joint of the left hind foot by injection of Mycobacterium butyricum in Freund's incomplete adjuvant in the foot pad. Seven days later animals received the following radiopharmaceuticals labelled with 99mTc (a) non-PEG-liposomes, (b) PEG-liposomes or (c) non-specific human polyclonal IgG. For each of the radiopharmaceuticals the in vivo distribution of the radiolabel was monitored both scintigraphically as well as by counting the dissected tissues at two, eight, and 24 hours after injection. RESULTS: The pharmacokinetics of the radiopharmaceuticals differed considerably (halflife in the blood: PEG-liposomes (18 hours) > 99mTc-IgG (3 hours) > non-PEG liposomes (1 hour)). The inflamed focus was visualised with each of the agents. The uptake of each of the radiopharmaceuticals in the inflamed ankle region correlated with their residence time in the blood (inflamed joint uptake: PEG liposomes (1.15% injected dose (ID)/ g) > 99mTc-IgG (0.35% ID/g) > non-PEG-liposomes (0.05% ID/g)). Quantitative analysis of the images showed that the inflamed ankle to background ratio was highest with the PEG-liposomes (7.5 at 24 hours after injection), while with the other two agents this ratio did not exceed 4. CONCLUSION: This study shows that 99mTc-labelled PEG-liposomes may be an excellent agent to visualise arthritis. Increased label uptake in the inflamed joint and increased target to background ratios can be obtained with PEG-liposomes because of their long circulating properties. In addition to their use as vehicles for scintigraphic imaging of arthritis PEG-liposomes might also be used for the site specific delivery of antirheumatic drugs.

Animals↗
PubMed1982

Effects of acute and long-term bronchodilator treatment on regional lung function in asthma assessed with krypton-81m and technetium-99m-labelled macroaggregates.

We have investigated the effect of acute and long-term bronchodilator treatment on the distribution of ventilation and perfusion in 15 asthmatics using a gamma camera, krypton-81m (for ventilation) and technetium-99m macroaggregate (for perfusion). Individual peak expiratory flow (PEF) values before bronchodilation were slightly or moderately below the predicted values. The simultaneous ventilation images (analysed visually) showed areas of delayed ventilation in all patients (mean distribution score on 3-point scale 2.1). After isoprenaline inhalation (240 micrograms) the mean PEF increased by 24%, but the distribution of ventilation remained virtually unchanged in all patients (mean score 2.0). Simultaneously defects in perfusion could be seen in all patients (mean score 1.5). After intensive treatment, when the mean PEF increased by a further 29%, the distribution scores of ventilation and perfusion fell to 0.8 and 0.9, respectively. The results indicate that, without intensive and long-term treatment, appreciable inequality of ventilation and perfusion are usual consequences of asthma; and suggest that although larger airways are dilated by isoprenaline inhalations residual bronchial obstruction may still remain in some smaller airways, maintaining uneven distribution. Perfusion disturbances seem to be secondary to changes in regional ventilation.

Adult↗
PubMed1986

Changes in pulmonary clearance of technetium labelled DTPA during haemodialysis.

An index of pulmonary epithelial permeability has been studied in 12 patients with chronic renal failure during haemodialysis. It was assessed by the half time clearance from lung to blood (t 1/2 LB) of a nebulised solution containing technetium labelled diethylene triamine pentacetic acid (99mTc DTPA). Six patients were cigarette smokers and six were non-smokers. The non-smokers had greater predialysis permeability (mean 37.7, range 24-54 min) than non-smokers without renal disease (mean 60.2, range 38-99 min; p less than 0.025). The t 1/2 LB was measured before dialysis and during the first half hour and the last half hour of dialysis in all 12 patients and also during other periods of dialysis in 10 of them. Dialysis lasted for five hours in 11 patients and four hours in one patient. There was no significant change in the t 1/2 LB of 99mTc DTPA during early dialysis; but as dialysis progressed there was a statistically significant increase in t 1/2 LB, suggesting a reduction of pulmonary epithelial permeability. These results show no increase in an index of pulmonary epithelial permeability in association with the pulmonary sequestration of neutrophils that occurs in early haemodialysis. They also suggest that in chronic renal failure the epithelial permeability is increased and that this can be modified by haemodialysis.

Adult↗
PubMed1980

Serendipity in technetium-99m dimethyl iminodiacetic acid cholescintigraphy: diagnosis of nonbiliary disorders in suspected acute cholecystitis.

Technetium-99m dimethyl iminodiacetic acid cholescintigraphy has contributed significantly to the diagnosis of acute and chronic biliary tract disorders. Yet attention should also be focused on the other structures visualized during the blood pool, hepatocyte, renal excretory, and intestinal phases of the study. Nonbiliary pathology was detected in 42 of 294 patients (14.3%) studied for suspected acute cholecystitis. The serendipitous detection of previously unsuspected abnormalities assisted in directing further work-up from suspected biliary disease and towards the real source of the patient's acute problem in 28 cases (9.5%).

Acute Disease↗
PubMed1983

The technetium-99m-sulfur colloid angiogram in suspected gastrointestinal bleeding.

Dynamic radionuclide angiography (5-sec. images) with technetium-99m-sulfur colloid proved to be helpful in 5 patients who presented with gastrointestinal bleeding. In 2, intermittently bleeding hypervascular lesions were seen on dynamic but not on static images; in 2 others, the dynamic images demonstrated hypervascular lesions better than the static scans; and in 1, the radionuclide angiogram localized colonic bleeding more accurately because of rapid peristalsis of extravasated tracer. The addition of the radionuclide angiogram to routine scintigraphy for gastrointestinal bleeding may be crucial for identification of hypervascular lesions and precise localization of bleeding sites.

Adult↗
PubMed1986

Acute acalculous cholecystitis: sensitivity in detection using technetium-99m iminodiacetic acid cholescintigraphy.

Forty-one proved cases of acute acalculous cholecystitis imaged with technetium-99m iminodiacetic acid (IDA) cholescintigraphy were retrospectively analyzed. After the exclusion of one indeterminate scan (showing poor initial hepatic uptake and excretion), the study yielded a 92.5% (37 of 40) sensitivity for the detection of cystic or common bile duct obstruction. Each of the three patients with false-negative scintigrams had other abnormal scintigraphic findings suggestive of biliary tract disease. Of the 20 patients (48.8%) with focal or diffuse gangrenous cholecystitis or perforation, seven (35%) exhibited either free peritoneal spill or increased pericholecystic activity to indicate the presence of advanced disease.

Acute Disease↗
PubMed1989

The kidney: imaging with Tc-99m mercaptoacetyltriglycine, a technetium-labeled analog of iodohippurate.

A new renal imaging agent, technetium-99m mercaptoacetyltriglycine (MAG3, mertiatide), is currently undergoing clinical trials. Like iodine-131 orthoiodohippurate (OIH)--and unlike all other available agents--it is avidly secreted by the renal tubules. Fifty patients underwent simultaneous renal imaging studies with I-131 OIH and Tc-99m MAG3. The superior physical properties of the Tc-99m label led to better image quality in all cases, largely due to count rates that were 50-fold better. In two patients, lesions were seen with MAG3 that were not visible with OIH. The biological properties of the two agents were found to be so similar that conventional diagnostic criteria for I-131 OIH could be used for Tc-99m MAG3 with only minor modifications.

Humans↗
PubMed1988

Experimental hemarthrosis in dogs: progressive synovitis monitored with technetium-99m pyrophosphate joint imaging.

We examined the time course of the development of hemorrhagic synovitis in response to repeated autologous blood injections into knee joints in mature dogs and the possible usefulness of joint imaging with technetium-99m pyrophosphate (Tc99m-PYP) in monitoring the early response of synovium to blood. Experimental hemarthrosis was induced in dogs by twice weekly injection of autologous blood into the knee joints. Sequential examination of the synovium at monthly intervals over a period of 12 weeks revealed early inflammatory cell infiltration and capillary neovascularization with eventual replacement of the normal fatty synovium by dense fibrous tissue. Serial Tc99m-PYP joint images demonstrated a progressive increase in isotope accumulation in the knees during the course of the study. Further isotope accumulation was observed after CO2 laser synovectomy. During the 24-week course of the entire study, no changes in joint cartilage or bone were observed by gross inspection or radiologic and light-microscopic examination. The findings indicate that the progressive proliferative, inflammatory, fibrotic changes in joint synovium associated with experimental hemarthrosis in dogs may be noninvasively and semiquantitatively assessed with the use of Tc99m-PYP scintigraphy. Evidence is also presented that the intensity of Tc99m-PYP joint accumulation (immediate static images) may not readily reflect synovial vascularity or synovial tissue mass.

Animals↗
PubMed1981

The high-risk angina patient. Identification by clinical features, hospital course, electrocardiography and technetium-99m stannous pyrophosphate scintigraphy.

We evaluated 193 consecutive unstable angina patients by clinical features, hospital course and electrocardiography. All patients were managed medically. Of the 193 patients, 150 (78%) had a technetium-99m pyrophosphate (Tc-PYP) myocardial scintigram after hospitalization. Of these, 49 (33%) had positive scintigrams. At a follow-up of 24.9 +/- 10.8 months after hospitalization, 16 of 49 patients (33%) with positive scintigrams died from cardiac causes, compared with six of 101 patients (6%) with negative scintigrams (p less than 0.001). Of 49 patients with positive scintigrams, 11 (22%) had had nonfatal myocardial infarction at follow-up, compared with seven of 101 patients (7%) with negative scintigrams (p less than 0.01). Age, duration of clinical coronary artery disease, continuing angina during hospitalization, ischemic ECG, cardiomegaly and a history of heart failure also correlated with cardiac death at follow-up. Ischemic ECG and a history of angina with a crescendo pattern also correlated with nonfatal infarction at follow-up. Patients with continuing angina, an ischemic ECG and a positive scintigram constituted a high-risk unstable angina subgroup with a survival rate of 58% at 6 months, 47% at 12 months and 42% at 24 and 36 months. We conclude that the assessment of clinical features, hospital course, ECG and Tc-PYP scintigraphy may be useful in identifying high-risk unstable angina patients.

Acute Disease↗
PubMed1987

Quantification of myocardial injury produced by temporary coronary artery occlusion and reflow with technetium-99m-pyrophosphate.

Previously, technetium-99m-stannous pyrophosphate (99mTc-PPi) has been used to localize and estimate the size of myocardial infarcts in animals after permanent coronary artery occlusion. This study tested the hypothesis that 99mTc-PPi accurately sizes myocardial infarctions produced by temporary coronary artery occlusion and reflow in dogs. Three groups of dogs were studied: group A underwent 3 hr of occlusion followed by 2 hr of reperfusion, with 99mTc-PPi injected 10 min after reflow (n = 10); group B underwent 3 hr of occlusion followed by 2 hr of reperfusion, with 99mTc-PPi injected 90 min after reflow (n = 11); and group C underwent 3 hr of occlusion followed by reflow with 99mTc-PPi injected at 10 min and again at 48 hr after reflow (n = 5). Myocardial slices from group A and B dogs were imaged in vitro. Group C dogs were imaged with single photon-emission computed tomography (SPECT) in vivo, and myocardial slices were imaged in vitro at the conclusion of the study. The extent of myocardial infarction was defined with triphenyltetrazolium chloride (TTC) staining, and coronary blood flow was estimated with radioactive microspheres. In addition, transmural myocardial tissue samples were taken from the center of the myocardial infarction, the lateral portion of the myocardial infarction, the normal myocardium adjacent to the lateral aspect of the infarcts, and from the normal myocardium and counted for 99mTc-PPi activity. A significant correlation was found between infarct size determined by areas of increased 99mTc-PPi uptake and that estimated from TTC staining for both group A (r = .89) and group B animals (r = .98).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Myocardial kinetics of technetium-99m-hexakis-2-methoxy-2-methylpropyl-isonitrile.

To study the potential usefulness of technetium-99m hexakis-2-methoxy-2-methylpropyl-isonitrile (Tc-MIBI) as a cardiac perfusion imaging agent, the left circumflex coronary arteries of 12 dogs were partially occluded. Eight additional control dogs had no coronary artery stenosis. Myocardial Tc-MIBI activities in the left circumflex and left anterior descending zones were continuously monitored by miniature implantable radiation detectors for 4 hr after administration of the isotope. The dogs were then killed. Serial gamma camera images were also acquired during the study. Heart rate, arterial blood pressure, pressure distal to the stenosis, and cardiac output did not change significantly during the experiment. Microsphere-determined regional myocardial blood flow was significantly reduced in the left circumflex distribution in the 12 dogs with coronary artery stenoses. In the 12 dogs with left circumflex coronary artery stenoses, the 4 hr fractional Tc-MIBI clearances from the normal and ischemic zones were minimal and equivalent (0.15 +/- 0.05 vs 0.15 +/- 0.07). In the eight control dogs, 4 hr fractional Tc-MIBI clearances from the left anterior descending and left circumflex artery zones were minimal and equivalent (0.11 +/- 0.06 vs 0.10 +/- 0.07). Four hour fractional Tc-MIBI clearance from the blood was 0.98 +/- 0.03 for the dogs with stenosis and 0.97 +/- 0.02 for the dogs without stenosis. One additional dog had complete occlusion of the left circumflex coronary artery followed by administration of Tc-MIBI and scandium-46-labeled microspheres. This heart was immediately sectioned and counted to determine the relationship of regional blood flow to Tc-MIBI distribution (r = .92).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Comparison of the myocardial uptake of a technetium-labeled isonitrile analogue and thallium.

The myocardial transmicrovascular transport of thallium-201 (201Tl) and technetium-99m hexakis(2-methoxyisobutylisonitrile) (MIBI) were compared during variable blood flow levels in nine blood-perfused, isolated rabbit hearts. Seventeen injections of radiolabeled albumin and EDTA as well as 201Tl and MIBI were performed by indicator-dilution techniques. When coronary flow was varied from 0.52 to 3.19 ml/g/min, myocardial extraction for MIBI averaged 0.38 +/- 0.09 (SD) whereas 201Tl myocardial extraction averaged 0.73 +/- 0.10 (p less than 0.001). Net extraction, which was calculated using end points of 1.8-4.9 minutes, averaged 0.41 +/- 0.15 for MIBI and was less than the 201Tl net extraction of 0.57 +/- 0.13 (p less than 0.001). The mean capillary permeability-surface area product for MIBI (0.44 +/- 0.13 ml/g/min) was one third of 201Tl (1.30 +/- 0.45 ml/g/min; p less than 0.001). However, parenchymal cell permeability-surface area product for MIBI (47.58 +/- 25.85 ml/g/min) was much higher than 201Tl (6.52 +/- 6.51 ml/g/min; p less than 0.0001), and apparent cellular volume of distribution for MIBI (15.15 +/- 3.31 ml/g) was also higher than 201Tl (10.19 +/- 4.00 ml/g; p less than 0.01). These data suggest that capillary permeability for 201Tl is greater than MIBI, but the reverse is true at the parenchymal cell wall. In addition, a new blood-perfused preparation is used for indicator-dilution techniques, and previously developed modeling analyses are also extended to these experiments.

Animals↗