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PubMedDate not supplied

Preoperative estimation of risk in hepatectomy using technetium-99m-galactosyl human serum albumin receptor amount by nonlinear 3-compartment model.

BACKGROUND/AIMS: Recently, we developed the method for measurement of the technetium-99m-diethylenetriamine-pentaacetic acid-galactosyl human serum albumin (Tc-GSA) receptor amount (R0) using a nonlinear 3-compartment model. We examined the usefulness of R0 for preoperative estimation of risk in hepatectomy. METHODOLOGY: Sixty-three patients who underwent hepatectomy in our hospital were examined for R0. These patients consisted of 26 cases of normal liver, 16 cases of liver fibrosis, and 21 cases of cirrhosis. R0 was measured by the nonlinear 3-compartment model of ligand-receptor binding without blood sampling in Tc-GSA scintigraphy. The expected remnant liver R0 after hepatectomy was calculated from CT volumetry before hepatectomy. RESULTS: The preoperative mean R0 of liver was 15.8 +/- 3.8 mg for Z0, 13.8 +/- 3.9 mg for Z1, and 6.9 +/- 2.3 mg for Z2. R0 in Z2 was significantly lower than Z0 and Z1 (p < 0.0001). Every patient whose remnant liver R0 was over 5 mg tolerated hepatectomy without any postoperative complications. Among 63 cases, 5 patients developed postoperative complications (two liver failures, two postoperative jaundice and one hepatic coma), and remnant liver R0 of these patients were under 5 mg. CONCLUSIONS: From these results, it can be seen that R0 of remnant liver is a useful parameter to decide indication of hepatectomy and predict postoperative complications.

Adult↗
PubMed1992

New agents labelled with technetium 99m for myocardial perfusion imaging.

New agents labelled with technetium 99m (99mTc) are now available for myocardial perfusion imaging. In this article the author reviews the biologic characteristics, the imaging protocols and the clinical usefulness of thallous chloride Tl 201, 99mTc-sestamibi and 99mTc-teboroxime (not yet available in Canada), as well as their complementary roles in the detection of coronary artery disease.

Clinical Protocols↗
PubMed1992

Role of technetium-99m diphosphonate and gallium-67 citrate bone scanning in the early diagnosis of infectious spondylodiscitis. A comparative study.

A comparative study of the parts played by technetium-99m diphosphonate and gallium-67 citrate bone scanning in the early diagnosis of infectious spondylodiscitis is presented. Nineteen patients were included in the study. All patients (11 men aged 19-70 years and eight women aged 18-72 years) had a history of back pain varying in duration from one to 15 weeks. A 99mTc diphosphonate bone scan was positive in 17 patients. The two patients with negative results had less than two weeks of back pain. The 67Ga citrate bone scan showed uptake in all patients.

Adult↗
PubMed1991

A quantitative model of technetium-99m-DTPA-galactosyl-HSA for the assessment of hepatic blood flow and hepatic binding receptor.

Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) was studied in normal volunteers and in patients with impaired liver function. The extrapolation approach originated the absolute dose of 99mTc-GSA in blood and the hepatic blood volume. The heart and liver regression curves were simultaneously fractionated into the three compartments (extrahepatic blood, hepatic blood and hepatocytes). Four differential equations were integrated with the six parameters as variables, and the smallest residual sum of squares was obtained by the damping Gauss-Newton method. The result of hepatic blood flow was 1603 +/- 144 (ml/min) in normal controls, which was compatible with previously reported values. Maximal removal rate (mg/min) showed statistically significant differences between the normal volunteers and patients with chronic hepatitis or liver cirrhosis. Our kinetic model of 99mTc-GSA can be used in the evaluation of liver function.

Adult↗
PubMed1989

Technetium-99m MAG-3 clearances after captopril in experimental renovascular hypertension.

Rats with one kidney clamped (2K1C), both kidneys clamped (2K2C), unilaterally nephrectomized with remaining kidney clamped (1K1C), and normals, were studied using 99mTc mercaptoacetyltriglycine ([ 99mTc]MAG-3) and 131I orthoiodohippurate ([131I]OIH). Clearances of [99mTc]MAG-3 and [131I]OIH were performed after constricted rats became hypertensive. Clearances were repeated after i.v. Captopril. Clearances of [99mTc]MAG-3 and [131I]OIH in normals didn't change significantly after Captopril. Clearances of [99mTc]MAG-3 and [131I]OIH decreased insignificantly after Captopril in the 2K2C model. in the 2K1C group, normal kidney clearance increased ([99mTc]MAG-3 p less than 0.01 and [131I]OIH p less than 0.025) and clamped kidney clearance decreased after inhibition ([99mTc]MAG-3, p less than 0.01, [131I]OIH p less than 0.02). Clearances increased in the 1K1C group after Captopril ([99mTc]MAG-3 p less than 0.0025 and [131I]OIH, p less than 0.001). The ratio of [99mTc]MAG-3 to [131I]OIH before Captopril was 0.81 and 0.84 after Captopril. Changes in renal function after Captopril depend on the model of renovascular hypertension and possibly the dose administered. Technetium-99m MAG-3 clearance parallels [131I]orthoiodohippurate in renovascular hypertension.

Animals↗
PubMed1989

[Echography and scintigraphy using technetium 99m pyrophosphate in the diagnosis of cardiac amyloidosis].

The diagnosis of amyloid cardiomyopathy was only based, until the last few years, on the results of invasive techniques. It seems presently that the combined contribution of cardiac sonography and scintigraphy using technetium 99m pyrophosphate, makes, most of the time, this diagnosis possible without need for additional examinations. This notion is illustrated by a typical case-report and data from the literature. Demonstration on the cardiac sonogram of a thickening of the walls-while the context and especially the electrocardiogram are not in favor of a left ventricular hypertrophy--associated with a very particular "hyperechoing" aspect and an abnormal fixation on the scintigram, may be considered specific of this disease.

Amyloidosis↗
PubMed1989

Technetium-99m (v) dimercaptosuccinic acid uptake in patients with head and neck squamous carcinoma: experience in imaging.

A recently developed imaging agent, technetium-99m (v) dimercaptosuccinic acid (99mTc (v) DMSA), has been used to assess head and neck squamous carcinoma (SCC). We have prospectively studied 62 patients of whom 53 had a histologically proven head and neck SCC. The remaining nine had benign lesions. The results of planar imaging in patients with primary disease yielded an 85% sensitivity and 78% specificity. Planar imaging in patients with cervical lymphadenopathy revealed a 59% sensitivity. Nineteen patients also had single photon emission computed tomography imaging which improved the image quality, spatial resolution and sensitivity of the investigation. Twenty-seven patients were scanned before and after radiotherapy and, of these, 96% showed positive uptake in the salivary glands with no evidence of tumor recurrence. This study has shown 99mTc (v) DMSA imaging provides a cheap and rapid method of investigating head and neck SCC and further studies are necessary to evaluate its role in the management of patients with this disease.

Adult↗
PubMed1989

[Quantification of myocardial infarct size by technetium-99m pyrophosphate single photon emission computed tomography].

Myocardial infarct size in 41 patients with the first attack of acute transmural myocardial infarction (MI) was assessed by technetium-99m pyrophosphate single photon emission computed tomography (99mTcPYP-SPECT). A ratio of the number of voxels of 99mTcPYP uptake into the infarct area to that into the thorax was calculated as a parameter of MI size. The ratio was positively correlated with both peak CPK activity (r = 0.53, p less than 0.005, n = 24) and extent score in 201TI-SPECT (r = 0.70, p less than 0.005, n = 14) significantly in patients with anterior MI but not in patients with inferior MI. There was also significant negative correlation between the ratio and the left ventricular ejection fraction (LVEF) measured by RI angiography in both acute (r = -0.67, p less than 0.005, n = 18) and chronic (r = -0.75, p less than 0.005, n = 25) phases in patients with anterior MI. Recovery in LVEF at chronic phase was noted in patients with small anterior MI but not with large anterior MI. 8 of 14 patients with inferior MI had right ventricular MI, that might have affected evaluation of MI size and resulted in no correlation between variables. It was suggested that 99mTcPYP-SPECT was a useful method to evaluate MI size and to predict prognosis of cardiac function in patients with anterior MI but not in patients with inferior MI.

Adult↗
PubMed1989

[Noninvasive diagnosis of cardiac involvement by technetium-99m-pyrophosphate (Tc-99m PYP) myocardial scintigraphy in 2 cases of familial amyloid polyneuropathy and 1 case of secondary amyloidosis].

To validate the significance of technetium-99m-pyrophosphate (Tc-99m PYP) myocardial scintigraphy in diagnosing cardiac amyloidosis, 2 patients with familial amyloid polyneuropathy (FAP) and 1 patient with amyloidosis secondary to chronic rheumatic arthritis were studied. All three patients had echocardiographic abnormalities, which were increased wall thickness of the interventricular septum and the left ventricular posterior wall, and granular sparkling appearance in the septum. In 2 patients with FAP, abnormal myocardial uptake of Tc-99m PYP was diffusely detected in Tc-99m PYP SPECT. In the remaining 1 patient with secondary amyloidosis, however, Tc-99m PYP SPECT showed no abnormality, although we had confirmed the presence of myocardial amyloid deposits (type AA amyloid protein) with high amount in the histological examination. Thus, these results indicate that Tc-99m PYP scintigraphy may have a limitation in detecting cardiac involvement in secondary amyloidosis although it is useful in FAP.

Adult↗
PubMed1989

[Clinical significance of the technetium-99m/thallium-201 overlap in acute myocardial infarction].

The region of overlap of thallium-201 (Tl) and technetium-99m pyrophosphate (Tc) was evaluated as a scintigraphic prognosticator of future necrosis. Serial time courses of myocardial perfusion according to Tl and left ventricular wall motion evaluated by two-dimensional echocardiography (2D echo) were used in 22 patients. In all, dual energy emission computed tomography (dual-SPECT) showed the Tl/Tc overlap on identical slices on the third post-infarction day. According to the results of dual-SPECT, the patients were categorized in three groups: nine with large Tl/Tc overlap (group A); five with small Tc accumulation and small Tl/Tc overlap (group B); and eight with large Tl defect and Tc accumulation, which are concordant with each other (group C). Tl-201 SPECT and 2D echo were attempted serially on the 1st and 2nd days, the 7th-10th days and the 28th-30th days. To estimate infarct size with Tl-201 SPECT, we measured pixel counts of eight short-axis images with the 40% cut-off level and computed "% defect". To evaluate the viability of the myocardium, "% Tl uptake" was computed from the ROIs both in the centers of the infarct areas and their border zones. 2D echoes of the left ventricular short axis at the chordae tendineae level were recorded to identify the time course of percent fractional area change (% FAC) of the ischemic left ventricular wall. The scintigraphic results were compared with the serial changes of regional ejection fraction in the areas of infarcts and ischemic lesions. The % defect remained unchanged in group C (29.2 +/- 11.5----25.7 +/- 8.3%); whereas those of groups A and B decreased significantly (21.2 +/- 11.3----9.9 +/- 6.3%, 13.8 +/- 2.6----5.4 +/- 2.9%, respectively). In groups A and B, % FAC improved significantly in the centers of the infarct areas and the border zones, but not in group C. Exercise-induced ischemia determined by redistribution of Tl at the chronic phase was observed more frequently in groups A and B than in group C. These findings indicated that more myocardium can be saved from necrosis in group A than in group C. In conclusion, it is suggested that there is considerable viable myocardium in patients with large Tl/Tc overlap on dual-SPECT.

Aged↗
PubMed1989

Cationic complexes of technetium for myocardial imaging.

Over the past 15 years a major goal of research in cardiovascular nuclear medicine has been the development of 99mTc complexes that could replace 201Tl and thus enhance the utility of myocardial perfusion imaging. This paper presents an overview of the current state-of-art of the development of cationic 99mTc complexes for this purpose. Cationic 99mTc complexes that have been evaluated as myocardial perfusion imaging agents in human volunteers and/or animals are discussed and classified on the basis of the oxidation state of the technetium center.

Animals↗
PubMed1989

Comparative study of regional cerebral blood flow images by SPECT using xenon-133, iodine-123 IMP, and technetium-99m HM-PAO.

Regional cerebral blood flow (rCBF) was measured by single photon emission computed tomography (SPECT) using 133Xe, N-isopropyl-p-[123I]iodoamphetamine ([123I]IMP) and [99mTc] hexamethylpropyleneamine oxime ([99mTc]HM-PAO) in 24 patients with cerebrovascular diseases. The greatest advantage of 133Xe SPECT was to be able to provide absolute rCBF values without arterial sampling. However, its image quality was very poor. Iodine-123 IMP SPECT provided rCBF images of higher quality and it had good correlation to 133Xe SPECT. Iodine-123 IMP SPECT provided the best images to detect mild ischemic lesions. It could detect obstructive or stenotic changes of large cerebral arteries very well except for a moderate stenosis of internal carotid artery. Technetium-99m HM-PAO SPECT also provided very good rCBF images and it had good correlation to 133Xe SPECT. However, the count-density ratios for the ischemic lesions to the contralateral presumed normal areas of [99mTc] HM-PAO SPECT were significantly higher than those of [123I]IMP SPECT.

Adult↗
PubMed1989

Dynamic SPECT with technetium-99m HM-PAO in meningiomas--a comparison with iodine-123 IMP.

Technetium-99m hexamethylpropyleneamine oxime ([99mTc]HM-PAO) has recently been introduced as an alternative to N-isopropyl-p-[123I]iodoamphetamine ([123I]IMP) for measurement of regional cerebral blood flow. This study compares dynamic SPECT studies using the two tracers in seven patients with meningiomas. Regions of interest were placed over the lesion and contralateral homologous presumed normal area. The counting-rate ratio for the lesion to the contralateral homologous area (L/N ratio) was then calculated in the first image. L/N ratios of [99mTc]HM-PAO single photon emission computed tomography (SPECT) were lower than those of [123I])IMP SPECT, particularly in hypervascular meningiomas. Furthermore, time-activity curves showed that the washout of [99mTc]HM-PAO in the tumors was very slow or incomplete, preventing an accurate assessment of vascularity of meningiomas with [99mTc]HM-PAO, as is generally possible with [123I]IMP.

Adult↗
PubMed1986

[Infarct size in patients with acute myocardial infarction estimated by emission computed tomography with technetium-99m pyrophosphate: relation to creatine phosphokinase release].

To evaluate the usefulness of single photon emission computed tomography (SPECT) with technetium-99m-pyrophosphate (99mTc-PYP) for estimating infarct size, we compared SPECT data with maximum creatine phosphokinase values. Background threshold was established in a series of phantom experiments. When a 40% cut-off was applied, the SPECT data most closely approximated actual phantom volumes. Therefore, the 40% cut-off level was used in the present study. In 10 patients with acute myocardial infarction, planar 99mTc-PYP myocardial scintigraphy and SPECT using a rotating gamma camera were performed two days after the initial myocardial infarction episode. The maximum creatine phosphokinase value (CPKmax) was also measured repeatedly following the episode. When the infarct size measured by SPECT using transaxial images and calculated by the pixel counts, it correlated very closely with CPKmax (r = 0.94). Most studies so far have reported that the CPKmax level reflects infarct size. We conclude that the infarct size as measured by 99mTc-PYP SPECT closely approximates the actual infarct size, and that this method is useful to determine the severity of infarcts clinically. Among the 10 patients in this series, three of five with infarcts greater than 60 ml died of pump failure. Therefore, we may be able to predict prognosis after accumulating more such cases and improving the methodology.

Aged↗
PubMed1986

Quantitative analysis of acute myocardial infarction using single photon emission computed tomography using technetium-99m pyrophosphate.

The usefulness of single photon emission computed tomography (SPECT) using technetium-99m pyrophosphate (99mTc-PPi) was evaluated in 15 patients with acute myocardial infarction. SPECT was performed with a rotating gamma camera after conventional planar images were made. Infarct size was measured from transaxial images of myocardial pyrophosphate uptakes. In each slice, the boundary was defined by subtracting 70 percent of the maximal counts and the number of voxels automatically counted. This subtraction rate was determined by phantom study and by comparing SPECT using 99mTc-PPi with thallium-201-gated myocardial scintigraphy (201Tl gated SPECT). The planar images showed diffuse uptakes in two of the 15 patients, and in these cases it was difficult to detect the infarct site. In contrast, SPECT images clearly imaged the infarct site consistent with the electrocardiographic findings, and they were definitely separated from the uptakes in the bones in all cases. Infarct size, ranging from 3.4 ml to 78.3 ml, correlated well with cumulative creatine kinase release (r = 0.84, p less than 0.01, y = 772x + 13900). Correlation of infarct size with peak serum creatine kinase level was also significant (r = 0.66, p less than 0.01, y = 10.6x + 693). In conclusion, SPECT with 99mTc-PPi is a useful means of investigating the spatial distribution of pyrophosphate uptake and of evaluating the size of myocardial infarction.

Aged↗
PubMed1988

Sipple's syndrome with liver tumors examined by iodine-131 MIBG and technetium-99m(V)-DMSA.

This case report describes the localization and categorization of tumors using 99mTc(V)-dimercaptosuccinic acid and [131I]metaiodobenzylguanidine scans in a very uncommon case of medullary thyroid carcinoma associated with pheochromocytoma (Sipple's syndrome) and hepatocellular carcinoma. Technetium-99m(V)-dimercaptosuccinic acid showed accumulation only in medullary thyroid carcinoma, but [131I]metaiodobenzylguanidine scans were positive in both medullary thyroid carcinoma and pheochromocytoma. In advanced Sipple's syndrome, combined use of [99mTc(V)]dimercaptosuccinic acid and [131I]metaiodobenzylguanidine may be useful for the categorization of tumor mass lesions and planning appropriate therapy.

3-Iodobenzylguanidine↗
PubMed1986

Synthesis and biological evaluation of technetium-99m MAG3 as a hippuran replacement.

A new technetium-chelating agent based on a triamide monomercaptide tetradentate set of donor groups, mercaptoacetylglycylglycylglycine (MAG3), was synthesized and evaluated. Chelation with 99mTc resulted in a single radiochemical product as expected. Studies in mice of [99mTc]MAG3 indicated excretion rates faster than omicron-iodohippurate (OIH) both in normal and in probenecid treated animals. Specificity for renal excretion was essentially complete. Clearance studies in rats resulted in 2.84 ml/min/100 g for [99mTc]MAG3, 2.17 for OIH, and 1.29 for [125I]iothalamate. Extraction efficiencies were 85% for [99mTc]MAG3, 69% for OIH and 39% for [125I]iothalamate. Probenicid depressed the clearance both of [99mTc]MAG3 and OIH at 25 and 50 mg/kg/hr, but to a greater extent with [99mTc]MAG3. The greater effect is offset, however, by the larger fraction secreted by the renal tubular cells. The animal results suggest that [99mTc]MAG3 may be a useful alternative to [131I]OIH.

Animals↗
PubMed1987

Animal evaluation of technetium-99m triamide mercaptide complexes as potential renal imaging agents.

Technetium-99m mercaptoacetylglycylglycylglycine (MAG3), a [99mTc]triamide mercaptide (N3S) compound has been synthesized in an attempt to obviate the stereochemistry problems associated with the diamide dimercaptide (N2S2) ligands. Because initial studies have been promising, the terminal glycine on the MAG3 compound has been varied to create a new series of N3S compounds. Twelve new N3S complexes were initially screened in mice and the more promising complexes, 99mTc mercaptoacetylgylcylglycyl-glycine [( 99mTc]MAG3), 99mTc mercaptoacetylgylcylglycyl-L-alanine [( 99mTc]MAG2-Ala), and both complexes of 99mTc mercaptoeacetylglycylglycyl-L-asparagine [( 99mTc]MAG2-Asn) and 99mTc mercaptoacetylglycylglycyl-L-glutamine [( 99mTc]MAG2-Gln), were further evaluated in rats utilizing constant infusion blood clearances, extraction efficiencies and protein binding assays. The renal excretion of all these complexes compared favorably with simultaneously administered [131I]OIH and [125I]iothalamate. The triamide mercaptide complexes represent a new ligand class for 99mTc, which may provide a variety of complexes for the evaluation of renal tubular function.

Animals↗