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PubMed1986

Observations on dermal blood flow as reflected by technetium-99m pertechnetate clearance.

Skin blood flow as reflected by the clearance rate of intradermal injections of Technetium-99m (99mTc) was studied in the skin of human volunteers and in a variety of clinical situations. In volunteers comparisons between the effect on clearance following intradermal injections of either lignocaine or lignocaine/adrenaline showed that the latter resulted in a dramatic reduction in the clearance rate of the technetium isotope and that such clearance curves exhibited no fast component. Clinical studies in grossly ischaemic skin revealed a similar absence of the fast component of isotope clearance and this was also the case for healed split thickness skin grafts. The dermal isotope clearance was also used in pedicle skin flaps both before and after clamping the axial pedicle in order to derive clearance ratios which would reflect the degree of neovascularisation to the flap. These preliminary observations suggest that the technique is safe, and easy to use in many clinical circumstances. We consider that it offers a valuable method by which changes in dermal blood flow may be quantified, when simultaneous control areas of isotope clearance are also studied. Suggestions are made for further avenues of study.

Adult↗
PubMed1993

HIV-salivary gland disease. Salivary scintiscanning with technetium pertechnetate.

The salivary disease in two patients with human immunodeficiency virus infection was investigated by technetium pertechnetate scintiscanning. Although there was good histologic evidence of benign lymphoepithelial disease, scintiscanning failed to delineate any salivary lesions. Technetium pertechnetate scintiscanning seems to be of little value in the detailed investigation of salivary disease in human immunodeficiency virus infection, though gallium scanning can help. Fine needle aspiration or biopsy remain the main diagnostic tools.

AIDS-Related Opportunistic Infections↗
PubMed1992

Tongue gastric choristoma: failure to localize by technetium-99m pertechnetate scan.

Congenital rests of gastric epithelium have been reported in a variety of head and neck locations. Presenting symptoms of these lesions range from an asymptomatic cyst to one which is compromising the airway. The true diagnosis is rarely suspected prior to excision. A case of a gastric choristoma of the tongue is presented which was noted at birth as an intermittently bleeding ulcer. Complete excision of the mass was difficult to ascertain due to poor delineation of the tumor margins from the tongue musculature. A postoperative technetium-99m pertechnetate scan failed to demonstrate residual gastric mucosa. Conservative management resulted in only transient healing of the ulcer. Repeat excision demonstrated abundant residual gastric mucosa. Technetium-99m pertechnetate scanning may not be a reliable indicator of ectopic gastric mucosa in the head and neck region.

Choristoma↗
PubMed1991

In vivo exposure of human lymphocytes to technetium-99m in nuclear medicine patients does not induce detectable genetic effects.

Recent reports have demonstrated that exposure of nuclear medicine patients to thallium-201 does not result in a detectable increase in mutation at the hprt locus in human lymphocytes. In an effort to study further the potential genetic effects of medical exposures to low dose radiation, we have examined chromosome aberrations and mutations in peripheral blood lymphocytes from nuclear medicine patients exposed to clinical doses of technetium-99m. Our results show that there is no exposure-related increase in chromosomal damage; furthermore, the data do not confirm earlier reports of exposure-related increases in mutations induced by technetium-99m.

Analysis of Variance↗
PubMed1996

Myocardial kinetics of technetium-99m teboroxime in the presence of postischemic injury, necrosis and low flow reperfusion.

OBJECTIVES: This study evaluated technetium-99m (Tc-99m) teboroxime kinetics in postischemic and partially necrotic myocardium with complete and low flow reperfusion using an isolated perfused rat heart model. BACKGROUND: Technetium-99m teboroxime has been proposed for use in the early diagnosis of reperfusion after thrombolysis on the basis of models of myocardial necrosis with complete reperfusion. Clinically, however, reperfusion is frequently incomplete, resulting in a mixture of necrotic, ischemic and postischemic tissue. METHODS: Hearts were classified into five groups: group 1 (n = 8, control); group 2 (n = 7, 30 min of no flow with complete reperfusion); group 3 (n = 12, 60 min of no flow to induce partial necrosis, followed by complete reperfusion); group 4 (n = 8, continuous low flow without flow interruption); and group 5 (n = 9, 60 min of no flow with low flow reperfusion). Buffer containing Tc-99m teboroxime was perfused for 15 min, followed by tracerfree buffer for 35 min, to evaluate uptake and clearance, respectively. RESULTS: Uptake slopes for groups 1 to 5 were (mean +/- SD) 3.0 +/- 0.7, 2.6 +/- 0.8, 2.1 +/- 0.5, 0.8 +/- 0.2 and 0.8 +/- 0.3, respectively (p < or = 0.0005 for groups 1, 2 and 3 vs. groups 4 and 5, and p = 0.003 for group 3 vs. groups 1 and 2). Clearance curves from groups 1 to 3 were best fit by a biexponential function (p < 0.001); those from groups 4 and 5 were monoexponential. In groups 1, 2 and 3, the initial clearance rate constants (ki) (0.9 +/- 0.5 x 10(-3); 1.0 +/- 0.2 x 10(-3); 1.1 +/- 0.5 x 10(-3) s-1, respectively) and the monoexponential rate constants (Kmono) (2.0 +/- 0.3 x 10(-4); 2.2 +/- 0.4 x 10(-4); 2.1 +/- 0.2 x 10(-4) s-1, respectively) were significantly greater than those in groups 4 and 5 (0.9 +/- 0.5 x 10(-4); 1.2 +/- 0.3 x 10(-4) s-1, respectively, p < or = 0.005). CONCLUSIONS: The uptake and initial clearance kinetics of Tc-99m teboroxime depend mainly on myocardial flow in this model. The presence of partial necrosis and postischemic injury has little effect on the initial clearance but leads to some reduction in uptake at normal flow rates. Evaluation of Tc-99m teboroxime kinetics may permit early noninvasive detection of inadequate reperfusion in acute myocardial infarction.

Animals↗
PubMed1994

Novel technetium ligands with affinity for the muscarinic cholinergic receptor.

The synthesis and preliminary biological characterization of two isomeric technetium labeled complexes (2,5,5,9-tetramethyl-4,7-diaza-7-(3' (R)-quinuclidinylcarboxymethyl)-2,9-decanedithiolato oxo 99/99mtechnetium(V), [99/99mTc]-1 and [99/99mTc]-2) designed to exhibit affinity to muscarinic cholinergic receptors are described. In vitro binding assays were conducted in mouse brain homogenates (whole brain-cerebellum) at 37 degrees C by the centrifugation method, where non-specific binding was defined by atropine (1 microM). The measured affinity (KD) of [99Tc]-1 for mAChR was 1.9 +/- 0.5 microM (mean +/- SEM; n = 3) and [99Tc]-2 was 4.5 +/- 0.5 microM (mean +/- SEM; n = 3). Scatchard analysis indicated that Bmax values were 10.6 +/- 0.5 and 16.9 +/- 0.5 pmol/mg tissue, respectively. In competition assays, [99Tc]-1 exhibited an apparent affinity (KI) of 16.5 microM (n = 2) against [125I] iododexetimide, whereas [99Tc]-2 exhibited an affinity (KI) of 105 microM. In vivo, 0.3% of the injected dose of [99mTc]-1 and [99mTc]-2 accumulated in the brain at 5 min after injection. These values indicate technetium analogues of neuroreceptor binding ligands can be synthesized and retain some affinity for the receptor.

Animals↗
PubMed2006

Prognostic value of exercise stress technetium-99m-tetrofosmin myocardial perfusion imaging in patients with normal baseline electrocardiograms.

Exercise stress electrocardiography is the recommended method for cardiac evaluation of patients with normal electrocardiograms (ECGs). There are no data to indicate an independent value of myocardial perfusion imaging (MPI) in predicting mortality in these patients. This study assessed the value of exercise stress MPI in predicting mortality in patients with normal baseline ECGs. We studied 319 patients (55 +/- 10 years of age; 180 men) with normal ECGs by exercise stress technetium-99m tetrofosmin MPI. End points during follow-up were cardiac and all-cause mortalities and hard cardiac events. A normal scan was detected in 190 patients (60%). Myocardial perfusion abnormalities were fixed in 59 patients (18%) and reversible in 70 (23%). During a mean follow-up of 7 +/- 1.2 years, 46 patients (14%) died. Death was considered cardiac in 28 patients (9%). Nonfatal myocardial infarction occurred in 12 patients (4%). Annual cardiac death rates were 0.4% in patients with normal perfusion, and 2.7% in patients with reversible defects. Annual total mortality rates were 1.1% in patients with normal perfusion and 3.4% in patients with reversible defects. In a multivariate analysis model, reversible perfusion abnormalities were associated with cardiac death (RR 2.8, 95% confidence interval 1.6 to 5.1) and hard cardiac events (RR 2.7, 95% confidence interval 1.5 to 4.5). Perfusion abnormalities in multivessel distribution were predictive of all-cause mortality (RR 2, 95% confidence interval 1.4 to 3.2). ST-segment depression was not significantly associated with events. In conclusion, stress technetium-99m tetrofosmin MPI provides independent information for predicting cardiac and overall mortalities in patients with normal ECGs. Reversible perfusion abnormalities, but not ischemic electrocardiographic changes, are predictive of outcome in these patients.

Electrocardiography↗
PubMed2005

New directions in the coordination chemistry of 99mTc: a reflection on technetium core structures and a strategy for new chelate design.

Bifunctional chelates offer a general approach for the linking of radioactive metal cations to macromolecules. In the specific case of 99mTc, a variety of technologies have been developed for assembling a metal-chelate-biomolecule complex. An evaluation of these methodologies requires an appreciation of the coordination characteristics and preferences of the technetium core structures and oxidation states, which serve as platforms for the development of the imaging agent. Three technologies, namely, the MAG3-based bifunctional chelates, the N-oxysuccinimidylhydrazino-nicotinamide system and the recently described single amino acid chelates for the {Tc(CO)3}1+ core, are discussed in terms of the fundamental coordination chemistry of the technetium core structures. In assessing the advantages and disadvantages of these technologies, we conclude that the single amino acid analogue chelates (SAAC), which are readily conjugated to small peptides by solid-phase synthesis methods and which form robust complexes with the {Tc(CO)3}1+ core, offer an effective alternative to the previously described methods.

Chelating Agents↗
PubMed1990

New technetium 99m-labeled brain perfusion imaging agents.

In developing new brain perfusion imaging agents, three types of neutral and lipid-soluble technetium 99m complexes have been reported: 99mTc-ethylene cysteinate dimer, 99mTc-hexamethyl propylene amine oxime, and 99mTc-boric acid adduct of technetium oxime. Structure-activity relationships of these complexes on brain uptake and retention have been investigated. The new 99mTc-brain perfusion imaging agents are useful in detecting various cerebral vascular abnormalities. The exact trapping mechanisms and their relationship with potential clinical applications still remain to be elucidated. However, initial clinical studies with 99mTc agents do show parallel clinical efficacy as those reported for the iodine 123-labeled brain perfusion agents, isopropyliodoamphetamine and N,N,N'-trimethyl-N'-[2-hydroxy-3-methyl-5-iodobenzyl]-1,3-propanediamine .

Animals↗
PubMed2002

Prediction of mortality in heart transplant recipients by stress technetium-99m tetrofosmin myocardial perfusion imaging.

Cardiac allograft vasculopathy is a major cause of mortality in heart transplant recipients. The aim of this study was to assess the prognostic value of stress myocardial perfusion imaging in heart transplant recipients. We studied 166 patients (age 54 +/- 10 years, 140 men) by symptom-limited bicycle exercise or dobutamine (up to 40 microg/kg/min) stress myocardial perfusion imaging 7.4 +/- 2.5 years after heart transplantation. An intravenous dose of 370 MBq of technetium-99m tetrofosmin was injected at peak stress and 24 hours after the stress test. An abnormal test was defined as reversible or fixed perfusion defects. Perfusion abnormalities were detected in 55 patients (33%). During a median follow-up of 2.5 years, 54 deaths (33%) occurred, 16 of which were due to cardiac causes. The incidence of perfusion abnormalities was higher in patients with subsequent cardiac death than in patients without subsequent cardiac death (69% vs 29%, p = 0.01). In an incremental multivariate Cox analysis, cardiac death was not predicted by age, gender, duration of transplantation, number of rejection episodes, or cytomegalovirus infection. In the next step, stress test parameters were added. The peak rate-pressure product was the only significant predictor at this step (risk ratio 0.84, 95% confidence interval 0.73 to 0.97, chi-square 7.7, p = 0.006). In the final step, the presence of abnormal myocardial perfusion was an independent predictor of cardiac death (risk ratio 3.5, 95% confidence interval 1.6 to 11.7, chi-square 4.7, incremental to clinical and stress test variables, p = 0.01). It is concluded that stress myocardial perfusion imaging with technetium-99m tetrofosmin single-photon emission computed tomography provides incremental data for the prediction of cardiac death in heart transplant recipients.

Echocardiography, Stress↗
PubMed1999

Dobutamine stress echocardiography and technetium-99m-tetrofosmin/fluorine 18-fluorodeoxyglucose single-photon emission computed tomography and influence of resting ejection fraction to assess myocardial viability in patients with severe left ventricular dysfunction and healed myocardial infarction.

The purpose of this study was to compare 2 different techniques--dobutamine-atropine stress echocardiography (DSE) and dual-isotope simultaneous acquisition (technetium-99-m-tetrofosmin/fluorine 18-fluorodeoxyglucose) single-photon emission computed tomography (DISA-SPECT)--for assessment of viable myocardium. One hundred ten patients (mean age 55 +/- 9 years) with left ventricular (LV) dysfunction (mean LV ejection fraction 27 +/- 13%) underwent both DISA-SPECT and DSE. A 16-segment scoring model was adopted for both techniques. Four types of wall motion during DSE were assessed: (1) biphasic, improvement at low dose (10 microg/kg/min) with worsening at high dose; (2) worsening, deterioration without initial improvement; (3) sustained, persistent or late improvement; and (4) no change. Viability criteria were biphasic, worsening, and sustained improvement with DSE. Viability criteria with DISA-SPECT were normal perfusion and metabolism (normal), concordantly mildly reduced perfusion and metabolism (subendocardial scar), or severely reduced perfusion and increased metabolism (mismatch). Myocardium was considered nonviable with DSE in case of unchanged wall motion, or moderate reduction or absence in both technetium-99m-tetrofosmin perfusion and fluorodeoxyglucose uptake with DISA-SPECT. Of 1,756 of 1,760 analyzable LV segments, 1,373 (78%) had severe wall motion abnormalities at baseline (severe hypokinesia, akinesia, or dyskinesia). Of these abnormal segments, 282 (21%) were considered viable during DSE (63 [5%] with biphasic response, 47 [3%] with ischemia, and 172 [13%]) with sustained improvement, whereas 1,091 (79%) were considered nonviable. With DISA-SPECT, 396 (29%) segments were considered viable (312 [23%] with matched perfusion/metabolism and 84 [6%] with mismatch), whereas 977 segments (71%) were considered nonviable. Both techniques showed agreement for viability in 201 segments and 896 were concordantly classified as nonviable. Disagreement was present in 276 segments of which 195 (71%) were nonviable with DSE and viable with DISA-SPECT. Overall agreement between the 2 techniques was 81% (kappa 0.46) in a subgroup of patients with an ejection fraction <25% 78% (kappa 0.39). Thus, DSE and DISA-SPECT show good agreement for assessing viable myocardium not influenced by resting ejection fraction. DSE underestimated the amount of viable tissue compared with DISA-SPECT.

Blood Pressure↗
PubMed1995

The role of pre-operative thallium-technetium subtraction scintigraphy in the surgical management of patients with solitary parathyroid adenoma.

Since 1985 we have practised scan directed unilateral cervical exploration for patients with primary hyperparathyroidism (HPT) on the basis of a solitary parathyroid adenoma, and who had a pre-operative thallium-technetium subtraction scintigram demonstrating one focus of activity (positive scan). Between 1985 and 1993, a total of 160 patients with proven HPT and a technically satisfactory scintigram underwent neck exploration. Of these, 96 had positive preoperative scans, 81 (84.4%) of which accurately predicted the site of the tumour subsequently retrieved at operation. Seventy-four (77.6%) with positive scans, and 80 of the entire group, underwent unilateral cervical exploration with removal of a presumed single adenoma. Seventy-eight (97.5%) of these patients were cured of their HPT; two patients demonstrated mild persistent hypercalcaemia. Median operating time was significantly reduced for patients having unilateral as opposed to bilateral operation. Our results suggest that, when positive, thallium-technetium subtraction scintigraphy will accurately predict the site of a solitary parathyroid adenoma in a high proportion of patients and will thus permit a unilateral parathyroid exploration in these individuals. The usefulness of the technique is limited by its low sensitivity for small tumours.

Adenoma↗
PubMed2002

Assessment of prosthetic vascular graft thrombogenicity using the technetium-99m labeled glycoprotein IIb/IIIa receptor antagonist DMP444 in a dog model.

INTRODUCTION: Prosthetic graft patency greatly depends on graft thrombogenicity. The concept of graft thrombogenicity is poorly understood and difficult to measure or quantify. In a study we tested the experimental radiopharmaceutical DMP444 and developed a suitable dog model. This agent is a radiolabelled ((99m)Technetium) glycoprotein IIb/IIIa receptor antagonist with a high affinity for activated platelets. It binds to platelets that are intimately involved in thrombus formation. The agent does not affect thrombocyte function, when used in a dose necessary for imaging. DMP444 does not require platelet harvesting and processing. Early imaging of thrombocyte aggregation sites such as vascular prostheses is possible within 4 hours after injection. MATERIAL AND METHODS: Adult Beagle dogs weighing 12-15 kg were used for the experiments. In 16 dogs a prosthetic patch was sewn onto the abdominal aorta (Bovine pericard: n=4, Dacron: n=6, Human Umbilical Vein: n=6). Imaging cycles after injection of (99m)Technetium-labelled DMP444 were performed on days 1, 7, 14 and 28 after surgery. RESULTS: We noticed differences in thrombus formation on the tested graft materials. The bovine pericard patches (n=4) showed a relatively high rate of thrombocyte aggregation. In the Dacron patches (n=6) aggregation was not seen. In 1 of 6 cases of human umbilical vein patches a measurable focal aggregation was recorded. CONCLUSION: The method outlined in this study is a relatively simple and reproducable method to visualize thrombocyte aggregation.

Animals↗
PubMed2000

In situ sorption of technetium using activated carbon

The sorption of technetium in pertechnetate form on carbon has been investigated. The sorption is pH dependent with maximal distribution coefficients, Kd, in the order of 10(6) at pH 2-4 for activated carbon with a grain size < or = 100 microm. The equilibrium time to reach such distribution coefficient was about 5 h at room temperature. The exact mechanisms for the sorption are not fully understood but reduction of Tc by the carbon might be an important process. Technetium can effectively and rapidly (5 l min(-1)) be sorbed from very large volumes (several hundred liters) of environmental waters on commercial cartridge filters impregnated with activated carbon. After incineration, the filters can be analyzed for 99Tc by conventional methods.

Journal Article↗
PubMed2000

Synthesis and biological evaluation of the four isomers of technetium-99m labeled ethylenecysteamine cysteine ((99m)Tc-ECC), the mono-acid derivative of (99m)tc-L,L-ethylenedicysteine.

A few years ago (99m)Tc-ethylenedicysteine ((99m)Tc-L,L-EC) had been proposed as an interesting substitute for technetium-99m labeled mercaptoacetyltriglycine (MAG3) as renal function tracer agent. It possesses in its structure two carboxylate functions and is in this respect different from other renal tracers such as (99m)Tc-N, N'-bis-(mercaptoacetyl)-2,3-diaminopropionate ((99m)Tc-CO(2)DADS), (99m)Tc-MAG3, and Hippuran, which have only one carboxylic group. To study whether both carboxylic acid groups of (99m)Tc-L,L-EC contribute to the efficient renal handling of this compound we synthesized and biologically evaluated the technetium-99m labeled isomers of L- and D-ethylenecysteamine cysteine (ECC), the mono-acid derivative of (99m)Tc-L,L-EC. Labeling of L-ECC or D-ECC with (99m)Tc using a direct or exchange labeling method yields for each of them two diastereomeric (99m)Tc complexes (A and B, in the order of elution during reversed phase high performance liquid chromatography) in relative amounts depending on the pH during labeling. In mice, all four isomers of (99m)Tc-ECC (LA, LB, DA, and DB) are cleared rapidly from the blood, mainly by the renal system. The isomers LB and DB show the most efficient renal handling, but none of the mono-acid derivatives has a urinary excretion rate as high as that of (99m)Tc-L,L-EC. The renal handling of the isomers of (99m)Tc-ECC is partly due to tubular secretion because the urinary excretion of these compounds is significantly lower in mice pretreated with probenecid. In the baboon, isomers DA and DB show a plasma clearance comparable to that of (99m)Tc-L,L-EC. The plasma clearance of isomers LA and LB is lower but still comparable to or higher than that of (99m)Tc-MAG3. In a human volunteer, isomer DB shows a plasma clearance rate only slightly lower than that of (99m)Tc-L,L-EC. Thus, it appears that the presence of one carboxylate in (99m)Tc-EC-like compounds can be sufficient for efficient renal handling. However, it is also evident that the configuration at the chiral carbon atom and the orientation of the oxotechnetium core determine in a significant way the biological characteristics.

Adult↗
PubMedDate not supplied

Clearance of technetium 99m N-NOET in normal, ischemic-reperfused, and membrane-disrupted myocardium.

BACKGROUND: Technetium 99m-labeled bis(N-ethoxy, N-ethyl dithiocarbamato) nitrido technetium(v) (99mTcN-NOET) is a new neutral cardiac perfusion imaging agent that has been shown to have very high uptake and retention in vitro. The purpose of this study was to determine the clearance kinetics of 99mTcN-NOET in control, ischemic-reperfused, and membrane-disrupted myocardium. METHODS AND RESULTS: After a 100 microCi (3.7 x 10(6) Bq) bolus of 99mTcN-NOET was injected, myocardial clearance was monitored for 1 hour by the use of a sodium iodide detector in 30 isolated, Krebs-Henseleit (KH) perfused rat hearts. Seven hearts were used as controls (group 1). In seven ischemic-reperfused hearts, tracer administration and uptake was followed by 30 minutes of no flow and 1 hour of reflow (group 2). In six additional ischemic-reperfused hearts, tracer administration was followed by deprivation of flow for 1 hour followed by 1 hour of reflow (group 3). Six hearts were perfused with a 0.5% Triton X-100 KH perfusate for 1 hour (group 4). Four hearts were perfused with KH for 10 minutes, followed by cyanide for 10 minutes (group 5). This cycle was repeated three times. Activities remaining in each heart at the end of each experiment were quantitated, and activity at peak uptake was calculated. The 99mTcN-NOET myocardial clearance was near linear in the control (0.6 +/- 0.4) and both ischemic-reperfused groups with virtually no fractional clearance (1.2% +/- 0.6% and 2.1% +/- 0.6%, respectively; p = NS). In the Triton X-100 membrane-disrupted hearts, clearance was substantial (94.2% +/- 4.0%; p < 0.0001 compared with the control and ischemic-reperfused groups). Cyanide treatment produced rapid clearance, which was arrested by a return to the standard KH perfusate. Peak uptake as a percentage of injected dose was 74.9% +/- 1.4% for all groups combined. CONCLUSION: Thus 99mTcN-NOET has extremely high myocardial retention after 1 hour in normal myocardium and is not significantly affected by ongoing myocardial ischemia or reperfusion injury in this model. Clearance is increased markedly in extreme conditions of membrane disruption. These data are consistent with the concept that 99mTc-NOET is localized predominantly in or on cell membranes. 99mTcN-NOET is a promising, new myocardial perfusion imaging agent that exhibits a stable myocardial distribution in the setting of acute developing injury.

Animals↗
PubMedDate not supplied

No gender bias in referral for coronary angiography after myocardial perfusion scintigraphy with technetium-99m tetrofosmin.

BACKGROUND: Several studies have shown that the application of diagnostic and invasive procedures varies between men and women. The purpose of this study was to assess if referral for coronary angiography after technetium-99m tetrofosmin myocardial perfusion scintigraphy in 616 patients with undiagnosed chest pain might demonstrate gender bias. METHODS AND RESULTS: The primary end point for this study was coronary angiography within 90 days of myocardial perfusion scintigraphy. Women had more normal perfusion images than men (207 [70.9%] vs 160 [50.5%], P < .05). Of 242 patients with abnormal images (157 men, 85 women), 28 men (17.7%) and 17 women (20.0%) were referred for further invasive testing (P = not significant). Referral for coronary angiography increased relative to the number of defects. Univariate analysis showed that reversible and persistent defects were the most predictive variables for referral to coronary angiography (odds ratio [OR] 5.45, 95% confidence interval [CI] 3.10-9.58, P < .001, and OR 2.67, 95% CI 1.52-4.67, P = .001, respectively). More importantly, multivariate analysis showed that reversible perfusion defects (OR 4.77, 95% CI 2.48-9.17, P < .001) and persistent perfusion defects (OR 2.14, 95% CI 1.11-4.14, P = .02) were predictive of subsequent coronary angiography. No significant association between gender and subsequent coronary angiography was found both in univariate and multivariate logistic regression analysis (OR 0.64, 95% CI 0.37-1.12, P = .12, and OR 0.70, 95% CI 0.36-1.36, P = .28, respectively). CONCLUSIONS: Our study reveals that after correction for the presence and the severity of myocardial perfusion abnormalities, men and women were referred to coronary angiography at a similar rate. Thus, based on the results of technetium-99m tetrofosmin myocardial perfusion imaging, no substantial evidence for a gender-related bias could be found in the referral for further invasive testing.

Analysis of Variance↗
PubMedDate not supplied

Design and synthesis of functionalized cyclopentadienyl tricarbonylmetal complexes for technetium-94m PET imaging of estrogen receptors.

Cyclopentadienyl tricarbonylmetal (CpTM, M = Re, (94m)Tc) complexes, some based on a typical nonsteroidal estrogen, were prepared with the aim of developing technetium- and rhenium-labeled imaging agents for estrogen receptor (ER) positive breast tumors. CpT[(94m)Tc] compounds with simple cyclopentadienyl substituents were first synthesized using a modified double ligand transfer reaction. The in vivo biodistribution of one of these CpT[(94m)Tc] complexes was determined by tissue dissection and microPET imaging. Novel C-ring substituted analogues of cyclofenil, a nonsteroidal compound known to bind the ER, were also prepared, and their ER binding was measured. Because of their low ER affinity, however, labeling and imaging studies of these compounds were not pursued. It is notable that the highest ER binding analogue, a CpTRe cyclofenil derivative, could be synthesized from the corresponding ferrocenyl cyclofenil analogue by the double ligand transfer reaction. This further demonstrates the versatility of the double ligand transfer reaction and indicates that the synthesis of technetium and rhenium radiolabeled agents for breast tumor imaging and therapy is also likely to be successful.

Animals↗