Tc-99m-leukocytes--is it an intracellular labelling?

Radiolabeled leukocytes have a potential for clinical use in detecting sites of inflammation. The increasing interest in the use of Tc-99m-labeled white blood cells (WBC) encourages exploration into the site(s) of binding of Tc-99m to the WBC components. Here we present the differential centrifugation study of the labeled leukocytes using a simple and low cost technique (SnTec). The results show most part of radioactivity bound to cytosol. We concluded that this is an intracellular labeling procedure that has the citoplasm, ribosomes unbound to membrane and soluble molecules as targets.     

Tc-99m MIBI uptake in traumatic vertebral fractures and metastatic vertebral lesions: Comparison with Tc-99m MDP

This study compared technetium-99m-hexakis-2-methoxyisobutyl-isonitrile (Tc-99m MIBI) with technetium-99m methylene diphosphonate (Tc-99m MDP) to determine whether Tc-99m MIBI could distinguish vertebral metastases from traumatic vertebral fractures. Twenty patients with traumatic vertebral fracture (and no malignant disease) and 14 patients with metastatic vertebral lesions were evaluated. Three to 4 hours after intravenous injection of Tc-99m MDP, images of the vertebrae in all patients were obtained. Corresponding Tc-99m MIBI images were acquired within 4 days after the Tc-99m MDP bone images were obtained. Computed tomography and magnetic resonance imaging demonstrated 24 vertebral traumatic fractures and 44 vertebral metastases. On conventional bone scans, Tc-99m MDP activity was increased in 92% of vertebral fractures and in 100% of vertebral metastases. However, on MIBI scans, no abnormal findings were observed in the vertebrae with fracture, although increased activity was seen in 73% of vertebral metastases. In this study, traumatic vertebral fractures tended to display no pathologic increases in Tc-99m MIBI uptake, whereas bone metastases usually appeared with high uptake. In light of the excellent specificity of Tc-99m MIBI scans compared with Tc-99m MDP bone scans, imaging studies that use Tc-99m MIBI scans may play an important complementary role in differentiating vertebral metastases from traumatic vertebral fractures.     

High-resolution single-photon emission computed tomography and X-ray computed tomography imaging of Tc-99m-labeled anti-DR5 antibody in breast tumor xenografts

A murine, apoptosis-inducing monoclonal antibody (mTRA-8) targeting human DR5 was radiolabeled with Tc-99m. The binding affinity (K(d)) and the number of DR5 receptors were measured in MD MBA-231-derived 2LMP cell lines that were "sensitive" or "resistant" to mTRA-8 killing. Single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) evaluated the Tc-99m-mTRA-8 retention and distribution within xenograft tumors; biodistribution analyses confirmed the levels. Scatchard assays showed specific and high binding affinity of Tc-99m-mTRA-8 to DR5; the killing efficacy of mTRA-8 was unchanged by Tc-99m labeling. There was no significant difference between sensitive and resistant 2LMP cells for K(d) values (1.5 +/- 0.3 nmol/L = acid labile), or DR5 receptors (mean/cell = 11,000). SPECT/CT imaging analyses at 6 h after injection of Tc-99m-mTRA-8 revealed the second 1.5 mm shell from the surface of the mammary fat pad tumors (n = 5; 5,627 mm(3)) retained 12.7 +/- 1.4%ID/g, higher than the other shells, with no difference between the sensitive and resistant 2LMP tumors. Binding of Tc-99m-labeled mTRA-8 in tumor was specific; excess unlabeled mTRA-8 blocked Tc-99m-mTRA-8 retention in tumor by 45%. Retention of Tc-99m-labeled isotype antibody in tumor was consistent with the blocking study, and 30% lower. These studies show that SPECT/CT imaging provided detailed distribution information of Tc-99m-labeled mTRA-8 within breast tumor xenografts. Imaging could provide a mechanism to assess DR5 modulation when DR5 therapy is combined with chemotherapy and radiation, and thereby aid in optimizing the dosing schedule.     

Sub-millimeter technetium-99m calibration sources.

PURPOSE: Small animal radioscintigraphic imaging systems aim to achieve sub-millimeter resolution. At the present time, sub-millimeter calibration sources that can be placed at will within an imaged volume are not readily available. We have developed a method for producing technetium-99m (Tc-99m) sources in less than 15 minutes with readily available reagents. PROCEDURES: Tc-99m pertechnetate [TcO(4)](-) was incubated with 45 microm to 106 microm diameter spherical anion exchange beads, washed, and mounted as desired for instrument calibration. RESULTS: The procedure yields spherical sources having between 6.8 microCi to 11.1 microCi of Tc-99m per source. This work shows that dual imaging of these sources using white light and radioscintigraphy permits measurement of system performance with high precision. CONCLUSION: Easily prepared, sub-millimeter Tc-99m spherical calibration sources are described, and it is demonstrated that such sources are useful for measuring the resolution and sensitivity of radioscintigraphic systems, such as those designed for small animal imaging.     

Tc-99m HMPAO labelled WBCs in the detection of occult sepsis in the intensive care unit

In a retrospective study involving 25 patients with occult sepsis in the ICU of Taichung Veterans General Hospital, the sensitivity and specificity of the new diagnostic method, Tc-99m HMPAO labelled white blood cells (WBCs) scan, were compared with other evaluating methods including clinical information, radiograph, ultrasound, bacterial culture, operative findings and pathological report. It was found that Tc-99m HMPAO labelled WBCs scans gave a sensitivity of 96.0%, a specificity of 84.4% and an overall accuracy of 87.3%, as well as the probable causes of false positive and false negative diagnoses were discussed. In conclusion, Tc-99m HMPAO labelled WBCs scans provide a reliable method for imaging of occult sepsis in the ICU.     

Direct 99mTc labeling of pegylated liposomal doxorubicin (Doxil) for pharmacokinetic and non-invasive imaging studies

Pharmacokinetic and organ distribution studies of liposomal drugs in humans are a challenge. A direct labeling method using (99m)Tc-N,N-bis(2-mercaptoethyl)-N',N'-diethyl-ethylenediamine (BMEDA) complex to label the commercially available pegylated liposomal doxorubicin, Doxil, has been introduced. Biodistributions of (99m)Tc-Doxil in normal rats were performed to evaluate the feasibility of using it for monitoring the pharmacokinetics of liposomes encapsulating drugs. Labeling efficiency of (99m)Tc-Doxil was 70.6 +/- 0.8% (n = 3). In vitro incubation of (99m)Tc-Doxil in 50% fetal bovine serum or 50% human serum at 37 degrees C showed good labeling stability with 72.3 +/- 3.6% or 78.6 +/- 1.8% of activity associated with Doxil at 24 h, respectively (n = 3). There was a two-phase blood clearance with half-clearance times of 2.2 and 26.2 h after bolus intravenous injection in normal rats. Distribution of (99m)Tc-Doxil at 44 h after injection had 19.8 +/- 1.3% of injected dose in blood, 14.1 +/- 1.7% in liver, 2.6 +/- 0.3% in spleen, 9.0 +/- 0.8% in bone with marrow, 6.0 +/- 0.5% in skin, and 15.3 +/- 4.3% in bowel (n = 5). Unencapsulated (99m)Tc-BMEDA had a very rapid blood clearance with a half-clearance time of only 0.12 h (n = 4). By using this (99m)Tc labeling method, biodistribution and pharmacokinetics of ammonium gradient liposomes encapsulating drugs can be determined by noninvasive scintigraphic imaging. This labeling method may be extended to (186)Re and (188)Re labeling to combine chemotherapy and radionuclide therapy for tumor treatment.     

A technetium-99m red cell survival technique for in vivo compatibility testing

A technique for labeling red cells with Technetium-99m was developed using in vitro reduction by stannous pyrophosphate. The use of Technetium-99m and Chromium-51 enabled simultaneous determination of 60-minute autologous and heterologous red cell survival using small aliquots. In vivo pretransfusion red cell compatibility in a patient with a panagglutinin was identical to that with 51Cr-labeled cells. Simultaneous testing of two heterologous donor units or testing multiple units in the course of a few days was also feasible. In nine studies (one patient and six healthy controls) no significant elution of the 99mTc was observed over 1 hour.     

A comparative evaluation of Tl-201 and Tc-99m sestamibi myocardial perfusion spect imaging in diabetic patients

Aim Myocardial perfusion scintigraphy (MPS) is an effective tool for early diagnosis of coronary artery disease (CAD) in type II diabetes mellitus (DM). The purpose of this study was to review the comparative findings of Tc-99m MIBI and Tl-201 MPS in defining normal and abnormal myocardial segments, type and extent of the perfusion defects with reference to coronary angiography findings in diabetic patients. Methods Thirty patients with type II DM who had abnormal Tc-99m MIBI MPS findings and underwent coronary angiography were included this study (20 male, 10 female; mean age was 64 ± 11 years). Those patients were also investigated with Tl-201 MPS thereafter. All scintigraphic images were evaluated semiquantitatively using a 20-segments myocardial model. The perfusion of myocardial segments, reversibility and severity of defects based on defect score were compared using the MIBI and Tl-201 images in relation to coronary angiography. Diffuse slow-washout of Tl-201 was also noted. Results A total of 600 myocardial segments were comparatively analyzed. Diagnostic concordance between both tracers in defining normal and abnormal perfusion on a segmental basis was 88% (κ = 0.71). The percentage of normal, reversible and non-reversible segments in the Tc-99m MIBI and Tl-201 study were 67–61%, 11–20% and 22–19% respectively. While the number of irreversible defects were similar for both tracers, more number of reversible defects were identified by Tl-201 MPS than Tc-99m MIBI (65 vs. 123, p = 0.001). No significant difference between the defect scores of both tracers was found. Conclusion MPS using both tracers offered agreement in defining or excluding perfusion abnormalities in a major part of the data. However, Tl-201 MPS yielded better detection rate of myocardial ischemia than Tc-99m MIBI MPS in diabetic patients.     

Intrapatient Comparison of 2-Deoxy-2-[F-18]fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose with Positron EmissionTomography/Computed Tomography to Tc-99m Fanolesomab (NeutroSpec) for Localization of Infection

Purpose This study evaluated the efficacy of 2-deoxy-2-[F-18]fluoro-d-glucose (FDG) with positron emission tomography/computed tomography (PET/CT) in comparison with Tc-99m fanolesomab (NeutroSpec) for imaging infection. Procedures Twelve patients with possible infection were studied with both FDG-PET/CT and Tc-99m fanolesomab. One patient was studied twice for a total of 13 paired studies. The final determination of the presence or absence of infection and the site(s) of infection at the time of imaging was made by an infectious disease physician using culture results and other relevant information. The sensitivity, specificity, and accuracy were calculated for each imaging study on a per paired study basis and a per lesion basis. In addition, the quality of lesion depicted was compared between the two studies. Results Three patients were determined not to have infection. Ten paired studies, in nine patients, were determined to have one or more sites of infection: seven had one site and three had two sites. On a per paired study basis the sensitivity, specificity, and accuracy of FDG-PET/CT were all 100%; for Tc-99m fanolesomab these parameters were 30, 100, and 46%, respectively (P < 0.01 for sensitivity and accuracy). On a per site basis the results for FDG-PET/CT were all 100% and for Tc-99m fanolesomab they were 23, 100, and 38% (P < 0.01 for sensitivity and accuracy). In the three sites of infection shown by both studies, FDG-PET/CT was judged to be superior in spatial resolution and anatomic localization compared to Tc-99m fanolesomab in all three sites. Conclusion FDG-PET/CT is superior to Tc-99m fanolesomab for detecting and localizing sites of infection.     

Localization of (99m)Tc-Labeled ApoB Synthetic Peptide in Arterial Lesions of an Experimental Model of Spontaneous Atherosclerosis

We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragment) to Watanabe heritable hyperlipidemic (WHHL) rabbits that foci of tracer uptake can be identified by external gamma camera imaging which correspond to regions of the aortas found to contain abundant atherosclerotic lesions at postmortem evaluation. Because (99m)Tc is preferred over (123)I for scintigraphic imaging, we prepared a (99m)Tc-labeled form of the SP-4 peptide, designated (99m)Tc-P199. To assess the feasibility of detecting atherosclerotic lesions using (99m)Tc-P199 and to compare the relative uptake of the (99m)Tc-labeled and radioiodinated peptides by such lesions, an admixture of (99m)Tc-199 and (125)I-SP-4 was administered to 11 WHHL and 2 normal rabbits. These animals were imaged for up to 3 h and were sacrificed 3--4 h after injection. The extent of aortic lesion involvement and radiotracer uptake were quantitatively compared by planimetric analysis of photographs of the endothelial surface, (99m)Tc-P199 ex vivo images and (125)I-SP-4 autoradiograms of the excised aortas. Pairwise correlation coefficients for planimetric analysis were as follows: photographs versus ex vivo images, r = 0.83, p = 0.003; photographs versus autoradiograms, r = 0.87, p = 0.001; ex vivo images versus autoradiograms, r = 0.83, p = 0.003. (99m)Tc-199 in vivo gamma camera images revealed relatively weak focal aortic uptake in 8 of 11 WHHL rabbits manifesting aortic lesions, and focal carotid artery uptake in 4 of 6 WHHL rabbits manifesting carotid lesions. Neither aortic nor carotid foci were visualized in the normal rabbits. We conclude that (99m)Tc-199 localizes specifically in atherosclerotic lesions and may be useful for external imaging of atherosclerosis.     

人血清白蛋白单克隆抗体的制备、鉴定与初步应用

目的制备人血清白蛋白(HSA)单克隆抗体(单抗)并以之制备亲和层析柱去除甘露聚糖结合凝集素(MBL)制剂中污染的HSA。方法采用杂交瘤技术制备单抗,通过ELISA、Western-blotting鉴定其特性;制备亲和层析柱去除MBL制剂中的污染HSA。结果筛选出4株稳定分泌HSA单抗的杂交瘤细胞株1C11、2E9、3A5和4H1,单抗亚类均为IgG1,亲和常数分别为7.19×109、1.46×109、6.94×109和2.28×1010;1C11与3A5的识别位点相似或相同,其他单抗识别位点均不同;4H1可与兔血清发生交叉反应,余者与其他种属血清均无交叉反应。结论所制备的HSA单抗1C11、2E9、3A5能特异结合HSA且与其他种属血清无交叉反应,抗HSA单抗亲和层析柱可用于去除人血清蛋白制剂中的污染HSA。     

Should imaging at stress always be followed by imaging at rest in Tc-99m MIBI SPECT?

Objectives. We addressed the question whether in patients with cardiac chest pain referred for stress myocardial perfusion scintigraphy, Tc-99m MIBI SPECT stress imaging should always be followed by a rest imaging procedure. Background. Using Tc-99m MIBI imaging a stress-rest sequence is usually performed implying that the resting study always follows the stress study irrespective of the results of the stress study. As a normal stress study would eliminate a subsequent resting study, it appears desirable to potentially define certain subsets of patients in whom a normal stress study can be expected in order to determine a more selective referral approach to the nuclear medicine department. The consequences of such a more streamlined approach would less impose on the logistics of the department of nuclear medicine, with decrease of investigation time, radiation dose, and costs in a time of retrenchment in the medical sector. Methods. A consecutive series of 460 patients (mean age 58.2 years) was studied who were stratified to 269 patients without prior myocardial infarction, and to 191 patients with documented evidence of a previously sustained mycoardial infarction. All patients underwent Tc-99m MIBI SPECT imaging according to a two-day stress-rest protocol. Results. Patients with and without a previous myocardial infarction showed suboptimal overall predictive accuracies for the exercise electrocardiograms (58% and 60%, respectively). In the total group of 460 patients, 94 (20%) patients showed a normal stress-rest Tc-99m MIBI SPECT; this occurred in 86/269 (32%) patients without a previous myocardial infarction and in only 8/191 (4%) patients with a previous myocardial infarction. Conclusions. Patients with a stress defect at Tc-99m MIBI SPECT imaging should always undergo a resting SPECT study irrespective of the clinical and stress electrocardiographic findings. As patients without a previous myocardial infarction had a normal stress SPECT study in almost one-third (32%) of patients compared to only 4% in patients with a previous myocardial infarction, it may be useful to employ different referral and imaging strategies i.e. a stress-only versus a stress-rest procedure. To schedule referring patients differently according to the presence or absence of a previously sustained myocardial infarction may be cost-saving, less demanding for the nuclear medicine personnel, and patient-convenient. In addition, a stress-only imaging procedure reduces radiation exposure to the individual patient.     

Three-dimensional sonographic evaluation of gallbladder contractility: comparison with cholescintigraphy

PURPOSE: To compare three-dimensional sonography (3D US) with quantitative cholescintigraphy for assessing gallbladder contractility. METHODS: Gallbladder radioactivity was assessed in 35 patients with suspected gallbladder disease using a gamma camera 5, 30, 60, and 90 minutes after technetium 99m (Tc-99m) DISIDA injection and 30 and 60 minutes after ingestion of a high-fat meal. Immediate gallbladder images were obtained via 3D US. Gallbladder radioactivity at 120 minutes after injection of Tc-99m DISIDA was defined as 100%, and gallbladder contractility was calculated. Gallbladder volume on 3D US was calculated using a dedicated software. Pearson correlation analysis and simple linear regression analysis were used. RESULTS: The mean gallbladder volume on 3D US was 25.3 ml after fasting and 6.6 ml after a high-fat meal. The mean gallbladder contractility index was 77.7% on cholescintigraphy (range, 18-99) and 73.4 on 3D US (range, 16.7-97.3). A linear correlation between cholescintigraphy and 3D US contractility indices was observed. The r value on Pearson analysis was 0.92 and R(2) of the coefficient of determination was 0.85. The difference in measured contractility between the 2 methods ranged from +21.5% to -15.0% (mean +/- SD, 4.4 +/- 8.7%). CONCLUSIONS: 3D US is a reliable and easy method for clinical measurement of the volume of the gallbladder and its contractility.     

Pulmonary sequestration of cardioplegia administered via the aortic root during aortocoronary bypass surgery

A semi-quantitative method was devised of tracing blood flow through the heart and lungs at the time of cardioplegia delivery and circulatory arrest of the heart during coronary artery bypass graft surgery (CABG). There were no previous studies confirming or disputing an accepted 'observation' by cardiac surgeons that cardioplegia solution does enter the lung parenchyma during cardiopulmonary bypass (CPB). This study was conducted as part of a larger (n = 142) double-blind, randomised, controlled, clinical research study. OBJECTIVE: The objective was initially to establish the efficacy of measures to prevent cardioplegia entering the lungs and, subsequently, to determine whether cardioplegia indeed circulates through the lung parenchyma or merely accumulates and 'pools'. METHOD: A prospective study on 20 consecutive patients (5 per group) admitted for CABG was made. Technetium (Tc-99m), a radioactive isotope, was added to the cold blood cardioplegia solution prior to cardioplegia delivery in order to track flow of cardioplegia solution. An independent nuclear medicine radiographer measured the samples with the use of a 'Curimentor' dose calibrator for presence and quantity of radiation in the samples. Decay was factored into the results. The Tc-99m tracer samples were also analysed using Gamma Acquisition and Analysis on the Genie 2000vdm Well Counter to confirm the presence and quantity of Tc-99m. RESULTS: In the four groups, it was confirmed that the pulmonary artery (PA) vent is 90-100% effective in retrieving any cardioplegia solution not drained by the atriocaval cannulae. CONCLUSIONS: The PA vent is effective in preventing cold blood cardioplegia solution from entering the lungs. Any cardioplegia that does enter the lung parenchyma during CPB circulates through the lungs and can be retrieved by a vent in the left atrium. This method may be useful in other studies that require investigation.     

运动、巯甲丙脯酸与巯甲丙脯酸运动肾显像检测原发性高血压的肾功能

目的：观察和分析运动（ＥＸ）、巯甲丙脯酸（ＣＡＰ）及巯甲丙脯酸运动（ＣＡＰ－ＥＸ）介入对轻中度原发性高血压（ＥＨ）患者肾功能的影响。方法：１０例正常志愿者和１５例轻中度原发性高血压患者,在１个月内完成基础双核素肾显像（ＢＳ－ＲＳ）、运动双核素肾显像（ＥＸ－ＲＳ）、巯甲丙脯酸双核素肾显像（ＣＡＰ－ＲＳ）及巯甲丙脯酸运动双核素肾显像（ＣＡＰ－ＥＸ－ＲＳ）４次检查。图像均按ＡＤＡＣ公司提供的计算机软件进行处理。结果：ＥＸ和ＣＡＰ－ＥＸ介入,ＧＦＲ,ＥＲＰＦ均明显降低（Ｐ＜００１）;而ＣＡＰ介入未见明显变化。ＥＨ组与对照组相应方法间ＧＦＲ,ＥＲＰＦ不存在显著差异（Ｐ＞００５）。１５例ＥＨ患者中,基础肾显像及巯甲丙脯酸肾显像结果均正常,而４０％（６／１５）的患者出现异常运动肾图,３０％（５／１５）出现异常巯甲丙脯酸运动肾图,二者同时异常的有５例,其中１例于ＣＡＰ－ＥＸ－ＲＳ介入时,异常更加明显,均表现为对称性的１３１Ｉ－ＯＩＨ和９９ｍＴｃ－ＤＴＰＡ排泄延迟,１３１Ｉ－ＯＩＨ肾图和９９ｍＴｃ－ＤＴＰＡ肾图曲线宽大,排泄段抬高。上述异常变化在１３１Ｉ－ＯＩＨ和９９ｍＴｃ－ＤＴＰＡ肾图曲线中,以９９ｍＴｃ－ＤＴＰＡ肾图     

Radioimmunoassay of glycosylated albumin with monoclonal antibody to glucitol-lysine

An immunoassay specific for glycosylated albumin was developed by the use of beads coated with antibody to human serum albumin (beads) and 125I-labelled monoclonal antibody to reduced bovine glucosylated low density lipoprotein. One bead was capable of binding 100 ng of serum albumin which had been treated with sodium borohydride (NaBH4) to reduce the Schiff base in the protein. The monoclonal antibody reaction with glucitol-lysine epitopes on the reduced glucosylated proteins and amino acids studied, including human serum albumin (HSA), bovine serum albumin and hippuryl-L-lysine. The detection limit of this assay was 100 pmol/mg HSA, which was sensitive enough for clinical use. The mean serum reduced glycosylated albumin concentration measured by this new method was significantly higher in diabetic patients (2.63 +/- 0.35 nmol/mg HSA, n = 32) than in healthy subjects (0.53 +/- 0.05 nmol/mg HSA, n = 38). The serum reduced glycosylated albumin concentration correlated with both hemoglobin A1c (r = 0.69, p less than 0.005) and the fasting blood glucose level (r = 0.51, p less than 0.005) in diabetic patients.     

Comparison of modification sites formed on human serum albumin at various stages of glycation

BackgroundMany of the complications encountered during diabetes can be linked to the non-enzymatic glycation of proteins, including human serum albumin (HSA). However, there is little information regarding how the glycation pattern of HSA changes as the total extent of glycation is varied. The goal of this study was to identify and conduct a semi-quantitative comparison of the glycation products on HSA that are produced in the presence of various levels of glycation.MethodsThree glycated HSA samples were prepared in vitro by incubating physiological concentrations of HSA with 15 mmol/l glucose for 2 or 5 weeks, or with 30 mmol/l glucose for 4 weeks. These samples were then digested and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the glycation products that were formed.ResultsIt was found that the glycation pattern of HSA changed with its overall extent of total glycation. Many modifications including previously-reported primary glycation sites (e.g., K199, K281, and the N-terminus) were consistently found in the tested samples. Lysines 199 and 281, as well as arginine 428, contained the most consistently identified and abundant glycation products. Lysines 93, 276, 286, 414, 439, and 524/525, as well as the N-terminus and arginines 98, 197, and 521, were also found to be modified at various degrees of HSA glycation.ConclusionsThe glycation pattern of HSA was found to vary with different levels of total glycation and included modifications at the 2 major drug binding sites on this protein. This result suggests that different modified forms of HSA, both in terms of the total extent of glycation and glycation pattern, may be found at various stages of diabetes. The clinical implication of these results is that the binding of HSA to some drug may be altered at various stages of diabetes as the extent of glycation and types of modifications in this protein are varied.     

The Acute Administration of Trimetazidine Modified Myocardial Perfusion and Left Ventricular Function in 31 Patients with Ischaemic Ventricular Dysfunction

Trimetazidine (TMZ) increases the mithocondrial oxidative metabolism and improves Tc-99m sestamibi uptake in myocardial single photon emission tomography (SPECT). The aim of this study was to evaluate whether the acute administration of TMZ improved myocardial perfusion and modified left ventricular ejection fraction (LVEF) in ischaemic left ventricular impairment. METHODS: Thirty-one patients (23 males, age 66 years) with prior myocardial infarction (>6 months) and echocardiographic LVEF < or = 45% underwent coronary angiography, rest basal myocardial SPECT (after 3-day placebo administration) and rest TMZ myocardial SPECT [after 3-day TMZ administration (60mg/die)]. The left ventricle was analysed in 16 segments. The summed placebo score (SPS) and the summed TMZ score (STS) were calculated with a 5-point scale (from 0 = normal uptake to 4 = absent uptake) by two blinded operators. The GATED Tc-99m SPECT was always provided. RESULTS: After TMZ administration GATED LVEF improved from 26.5+/-9.7% to 29.1+/-11.3% (p = 0.04) and left ventricular end-systolic volume (LVESV) was reduced from 90.2+/-40.7 to 85.6+/-39.2 ml/mq (p = 0.006). Similarly the addition of TMZ to myocardial SPECT significantly reduced the STS compared to SPS (21.5+/-11 vs. 26.6+/-10.5 p = 0.0001). Eleven patients (35.5%) had an echocardiographic LVEF < or = 30%; in these patients who had severe ventricular dysfunction, GATED LVEF and LVESV did not change after TMZ (20.2+/-5.7% vs. 21+/-6.9% p =0.6; 116.7+/-35.3 ml vs. 112.6+/-32.3 ml p = 0.08, respectively). CONCLUSION: In comparison with placebo, the addition of TMZ to myocardial Tc-99m tetrofosmin SPECT improved myocardial perfusion and LVEF, reducing LVESV. These effects were lost in patients with more severe ventricular dysfunction.     

Role of99mTc-IDA cholescintigraphy in evaluating biliary tract disorders

Technetium-99m IDA cholescintigraphy has provided a new, noninvasive means of visualizing biliary tract function. It has become the procedure of choice in patients with suspected acute cholecystitis because of its ability to most accurately detect functional obstruction or patency of the cystic duct as opposed to ultrasound's ability to detect only anatomic changes such as the presence of calculi or a thickened gallbladder wall. These latter findings are more important in establishing the diagnosis of chronic cholecystitis where ultrasound shares a position of prime importance with the oral cholecystogram. Tc-99m IDA cholescintigraphy has also been particularly useful in evaluating bile leaks, biliary-enteric anastomosis patency and the post-cholecystectomy patient with recurrent pain. In the patient with cholestasis, ultrasound is usually the procedure of choice since it establishes whether or not ductal dilatation is present and frequently can determine the cause of obstruction. Cholescintigraphy has played an ancillary role in many cases by demonstrating the level of partial obstruction, but it does not have the anatomic resolution to visualize the cause of obstruction. Occasionally, in the evaluation of cholestasis, cholescintigraphy has proven to be the only modality which has identified the presence of acute common duct obstruction or localized intrahepatic ductal obstruction. All in all, Tc-99m IDA cholescintigraphy has had a dramatic impact upon hepatobiliary diagnosis.     

Tc-99m-MIBI双时相显像评价甲状旁腺机能亢进症的临床研究

目的:在甲状旁腺机能亢进症患者中,评价双时相Tc-99m-MIBI甲状旁腺显像对异常甲状旁腺组织的诊断和定位。方法:35例临床检查和生化指标提示甲状旁腺机能亢进的患者,手术前1周内行双时相Tc-99m-MIBI甲状旁腺平面显像。注射740MBq的Tc-99m-MIBI,15分钟和2小时后,分别进行颈胸前位平面显像,部分病人在延迟相还进行SPECT断层显像。结果:Tc-99m-MIBI甲状旁腺显像结果与手术结果对比,双时相Tc-99m-MIBI甲状旁腺平面显像对甲状旁腺腺瘤诊断灵敏度是75%(27?36),而SPECT断层显像的灵敏度是86%(31?36);甲状旁腺增生诊断灵敏度是50%(2?4)。结论:本研究认为双时相Tc-99m-MIBI甲状旁腺显像对甲状旁腺腺瘤的诊断和定位有较高的临床价值,尤其是SPECT断层显像,而对甲状旁腺增生的诊断,有必要进行进一步研究。