Valor diagnóstico de la gammagrafía de perfusión miocárdica con 99mTc-Tetrofosmina en mujeres previamente revascularizadas / Diagnostic value of myocardial perfusion imaging with 99mTc-tetrofosmin in a population of women previously revascularized

Fundamento y objetivo: Se trata de un estudio transversal donde se han determinado los valores de sensibilidad y especificidad del estudio de perfusión miocárdica con 99mTc-Tetrofosmina en protocolo de un día tras estímulo farmacológico con dipiridamol, en una población de mujeres previamente revascularizadas, así como la relación con los territorios vasculares coronarios, tomando como referencia la coronariografía. Pacientes: Se han estudiado con carácter retrospectivo 53 historias clínicas de mujeres sometidas a una prueba de perfusión miocárdica y a una coronariografía de control. Resultados: Los valores de sensibilidad y especificidad para la población fueron de 64,29 por ciento y 75,0 por ciento respectivamente. Por territorio arterial coronario, los valores de sensibilidad y especificidad para la arteria DA fueron de 68,75 por ciento y 75,0 por ciento respectivamente, para la Cx de 37,93 por ciento y 88,89 por ciento, y para la CD de 46,43 por ciento y 60,71 por ciento. Conclusiones: En las mujeres que han sido previamente revascularizadas, la gammagrafía de perfusión miocárdica con 99mTc-Tetrofosmina y dipiridamol en protocolo de un día parece ser una prueba idónea para realizar el seguimiento de pacientes.

Background: This is a cross-sectional study to identify the values of sensitivity and specificity of myocardial perfusion imaging with 99mTc-tetrofosmin one-day protocol after pharmacological stimulation with dipyridamole in a population of women previously revascularized and the relationship of findings to coronary vascular territories, with coronary angiography as a gold standard. Patients We studied retrospectively 53 medical records of women undergoing myocardial perfusion test and control coronary angiography. Results: The sensitivity and specificity for the population were 64.29 percent and 75.0 percent respectively. For coronary artery territory, the values of sensitivity and specificity for the LAD were 68.75 percent and 75.0 percent respectively, for Cx of 37.93 percent and 88.89 percent, and for the RCA 46.43 percent and 60.71 percent. Conclusions: In women who have been previously revascularized, myocardial perfusion scintigraphy with 99mTc-tetrofosmin and dipyridamole in one-day protocol seems to be a suitable test to monitor patients.

The Clinical Usefulness of 99mTc-Tetrofosmin Scintigraphy in the Diagnosis of Lung Neoplasmas and Mediastinal Lymphoid Node Involvement / 华中科技大学学报（医学）（英德文版）

Summary: In order to investigate the clinical significance of 99mTc-Tetrofosmin (TF) seintigraphy in the evaluation of lung cancer and mediastinal lymphoid node involvement, 33 patients with pulmonary neoplasmas were subjected to both 99mTc-TF scintigraphies and CT scans in one week before their operations or puncturations. All the images were judged visually and the emission images were analyzed with semi-quantitative methods in addition. The results of each group were compared. There was marked difference in target/non-target (T/N) ratio between the lung cancer group and the benign lesion group (P<0.001). Moreover, in the lung cancer group, T/N ratio in tomographies was significantly higher than that in planar images (P<0.01). The sensitivity and accuracy of semi-quantitative analysis in 99mTc-TF SPECT were significantly higher than those of CT in the diagnosis of pulmonary neoplasmas (P<0.05 and P<0.01 respectively), so was the sensitivity of 99mTc-TF SPECT vs CT in the diagnosis of mediastinai lymphoid node metastasis (P<0.05). It was also found that epidermoid squamous cell carcinomas and adenocarcinomas had a higher T/N ratio than in small cell carcinomas (P<0.05), and 2 h washout rate (WR) of adenocarcinomas was higher than that of epidermoid squamous cell carcinomas (P<0.05). In conclusion, 99mTc-TF scintigraphy showed a favorable diagnostic accuracy in appraising lung cancers and mediastinal lymph node metastases. Furthermore semi-quantitative technology can improve the accuracy, and is potential to offer some information about histological type of the cancer tissue. Therefore, 99mTc-TF scintigraphy will be a useful tool in the diagnosis and staging of lung cancer.

Effectiveness of 99mTc-tetrofosmin for assessment of heart functions in micropigs

This study examined the suitability of a nuclear imagingtechnique using 99mTc-tetrofosmin as an agent to assess theheart functions of healthy micropigs. The mean age of thepigs was 360 days (male), and the mean body weight was35.3kg ranging from 34.5-36kg. There were no significantperfusion defects in any of the reconstructed images.Gated single-photon emission computed tomographyimaging can be used to calculate the ventricular volumeand ejection fraction (EF). In this case, an EF of 79% wascalculated from the ventricular volume of the end-systolicimage (10 ml) subtracted from that of the end-diastolicvolume (49 ml). A perfusion defect (particularly the apex,lateral wall) is unlikely because of the presence of apreserved wall motion in a segment with a defect. It isconcluded that quantitative cardiac scintigraphy, using99mTc-tetrofosmin is an adequate technique for estimatingthe heart functions of healthy micropigs.

Comparative Uptake of Tc-99m Sestamibi and Tc-99m Tetrofosmin in Cancer Cells and Tissue Expressing P-Glycoprotein or Multidrug Resistance Associated Protein / 대한핵의학회잡지

PURPOSE: 99mTc-sestamibi (MIBI) and 99mTc-tetrofosmin have been used as substrates for P-glycoprotein (Pgp) and multidrug resistance associated protein (MRP), which are closely associated with multidrug resistance of the tumors. To understand different handling of radiotracers in cancer cell lines expressing Pgp and MRP, we compared cellular uptakes of 99mTc-MIBI and 99mTc-tetrofosmin. The effects of cyclosporin A (CsA), well-known multidrug resistant reversing agent, on the uptake of both tracers were also compared. MATERIALS AND METHODS: HCT15/CL02 human colorectal cancer cells for Pgp expressing cells, and human non-small cell lung cancer A549 cells for MRP expressing cells, were used for in vitro and in vivo studies. RT-PCR, western blot analysis and immunohistochemistry were used for detection of Pgp and MRP. MDR-reversal effect with CsA was evaluated at different drug concentrations after incubation with MIBI or tetrofosmin. Radioactivities of supernatant and pellet were measured with gamma well counter. Tumoral uptake of the tracers were measured from tumor bearing nude mice treated with or without CsA. RESULTS: RT-PCR, western blot analysis of the cells and immunochemical staining revealed selective expression of Pgp and MRP for HCT15/CL02 and A549 cells, respectively. There were no significant difference in cellular uptakes of both tracers in HCT15/CL02 cells, but MIBI uptake was slightly higher than that of tetrofosmin in A549 cells. Co-incubation with CsA resulted in a increase in cellular uptakes of MIBI and tetrofosmin. Uptake of MIBI or tetrofosmin in HCT15/CL02 cells was increased by 10- and 2.4-fold, and by 7.5 and 6.3-fold in A549 cells, respectively. Percentage increase of MIBI was higher than that of tetrofosmin with CsA for both cells (p< 0.05). In vivo biodistribution study showed that MIBI (114% at 10 min, 257% at 60 min, 396% at 240 min) and tetrofosmin uptake (110% at 10 min, 205% at 60 min, 410% at 240 min) were progressively increased by the time, up to 240 min with CsA. But increases in tumoral uptake were not significantly different between MIBI and tetrofosmin for both tumors. CONCLUSION: MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators in vitro, but these differences were not evident in vivo tumoral uptake. Both MIBI and tetrofosmin seem to be suitable tracers for imaging Pgp- and MRP-mediated drug resistance in tumors.

Comparison of the Uptakes of 99mTc-sestamibi and 99mTc-tetrofosmin in Cancer Cell Lines Expressing Multidrug Resistance / 대한핵의학회잡지

PURPOSE: Cellular uptakes of 99mTc-sestamibi (MIBI) and 99mTc-tetrofosmin into cancer cell lines expressing multidrug resistance (MDR) were investigated and compared. The effects of verapamil and cyclosporin A, well-known multidrug resistant reversing agents, on cellular uptakes of both tracers were also compared. MATERIALS AND METHODS: Doxorubicin-resistant HCT15/CL02 human colorectal cell and doxorubicin-resistant K562 (Adr) and vincristine-resistant K562 (Vcr) human leukemic cells were studied. RT-PCR analysis was used for the detection of mdr1 mRNA expression. MDR-reversal effects with verapamil and cyclosporine A were evaluated at different drug concentrations after incubation with MIBI and tetrofosmin for 1, 15, 30, 45 and 60 min, using single-cell suspensions at 1x10 (6) cells/ml incubated at 37 degrees C. Radioactivity in supernatants and pellets were measured with gamma well counter. RESULTS: The cellular uptakes of MIBI and tetrofosmin in K562 (Adr) and K562 (Vcr) were lower than those of parental K562 cell. In HCT15/CL02 cells and K562 (Adr) cells, there were no significant difference in cellular uptakes of both tracers, but cellular uptake of MIBI was higher than that of tetrofosmin in K562 (Vcr) cells. Coincubation with verapamil resulted in a increase in cellular uptakes of MIBI and tetrofosmin. Verapamil increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 11.9- and 6.8-fold, by K562 (Adr) cell by 14.3- and 8-fold and by K562 (Vcr) cell by 7- and 5.7-fold in maximum, respectively. Cyclosporin A increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 10- and 2.4-fold, by K562 (Adr) cell by 44- and 13-fold and by K562 (Vcr) cell by 18.8- and 11.8-fold in maximum, respectively. CONCLUSION: Taking together, MIBI and tetrofosmin are considered as suitable radiopharmaceuticals for detecting multidrug resistance. However, MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators. Since cellular uptakes of both tracers might differ in different cell types, further experiments regarding differences in cellular uptakes between cell types should be explored.

99mTc-tetrofosmin, 131I Whole Body Scan and Thyroglobulin in Detecting Differentiated Thyroid Carcinoma Metastases

PURPOSE: The purpose of this study was to assess the detectability of differentiated thyroid carcinoma metastases by 99mTc-tetrofosmin and to compare these results with a 131I whole body scan (131I WBS). The results of two scans were also compared with the T4 off-thyroglobulin (Tg) concentration. METHODS: A prospective study was performed on 43 patients (40 females, 3 males) with differentiated thyroid carcinomas (41 papillary, 2 follicular) having undergone a total thyroidectomy, and received 100~200 mCi (3,700~7,400 MBq) of radioiodine for ablation of residual thyroid tissue, or treatment of metastasis. All patients (n=43) had a 99mTc- tetrofosmin scan, and a 131I WBS following the discontinuation of thyroid hormone replacement. The T4 off-Tg level was checked immediately prior to the radioiodine therapy, with T4 off-Tg levels above 20 ng/ml defined as positive for metastasis or a remnant disease. RESULTS: Cervical metastases were considered in 6 patients and distant metastases in 7, based on the clinical, radiological, and histopathological findings. The 131I WBS (70.2%) was much more sensitive than the 99mTc-tetrofosmin scan (29.8%) in demonstrating the residual thyroid tissue following surgery. The 131I WBS revealed cervical metastases in 3 of the 6 patients, but only 2 of the 6 were revealed by the 99mTc-tetrofosmin scan. Of the 3 patients with negative 131I WBS, two were detected by the 99mTc-tetrofosmin scan. The sensitivities of the 131I WBS and 99mTc-tetrofosmin scan in diagnosing distant metastases were comparable (71%, and 57% respectively), but in 2 patients with negative 131I WBS, the 99mTc-tetrofosmin revealed distant metastases. The specificities of the 131I WBS and 99mTc-tetrofosmin scan were not comparable (100%, 97%, respectively) in the diagnosis distant metastases. The mean T4 off-Tg level of the patients with cervical or distant metastases was 317 ng/ml, with a sensitivity and specificity of 100%, and 83% respectively. In the patients with a T4 off-Tg level above 50 ng/ml, the two scans and clinical studies could not reveal any metastases in 3 of the patients. CONCLUSION: Although the specificity of the 99mTc-tetrofosmin scan was slightly lower than that of the 131I WBS, it is a useful tool for detecting cervical or distant metastases in differentiated thyroid carcinomas and does not require prior withdrawal from thyroid hormones. Therefore the concomitant use of a 99mTc-tetrofosmin scan, a 131I WBS and Tg, is more effective in detecting metastases in differentiated thyroid carcinomas.

Gender Difference of Accuracy in Detecting Coronary Artery Disease by Myocardial Perfusion SPECT / 대한핵의학회잡지

PURPOSE: Myocardial SPECT is an effective test for detecting coronary artery disease in the general population. But the diagnostic accuracy between sexes is not defined. The purpose of this study is to compare the diagnostic accuracy between males and females. MATERIALS AND METHODS: One hundred and seventy seven male and 98 female patients who underwent myocardial SPECT within 1 month of coronary angiography were studied. Myocardial SPECTs were considered abnormal if fixed or reversible perfusion defects were detected. Stenosis severity of > or = 50% luminal diameter reduction of any artery defined coronary artery disease (CAD). RESULTS: Overall sensitivity for detection of CAD was 98% in men and 97% in women (p=not significant). However, specificities, accuracies, and positive predictive values (PPV) in men and women were 49% vs 31% (p<0.05), 81% vs 57% (p<0.01), 78% vs 48% (P<0.01), respectively Diagnostic accuracies for detection of right coronary artery disease were not different in both sexes, however, accuracies for detection of left anterior descending artery disease and left circumflex artery disease were significantly lower in female (p<0.05). CONCLUSION: A significant difference of diagnostic accuracy between sexes, especially in LAD and LCx disease, was noted. Artifacts from breast attenuation might be a cause for the lower diagnostic accuracy in female.

Comparison of 99mTc-tetrofosmin and 99mTc-sestamibi Myocardial Perfusion SPECT in Detecting Coronary Artery Fisease / 대한핵의학회잡지

PURPOSE: Tc-99m-tetrofosmin(TF) is a recently proposed myocardial imaging agent which has similar biokinetic characteristics to Tc-99m-sestamibi(MIBI). The aim of this study was to compare TF and MIBI myocardial perfusion SPECTs in detecting coronary artery disease. MATERIALS AND METHODS: One hundred and sixty patients(l0l males, 59 females, mean age 57+/-9 yr) who had undergone both myocardial perfusion SPECT (M- SPECT) and coronary angiography within 1 month were studied. M-SPECT was performed using TF in 115 patients and MIBI in 45 patients. Stress-rest one day protocol was used in all patients A coronary stenosis was considered significant when the luminal diameter > or =50% was compromised. The chi square test was used to compare, differences in sensitivity and specificity between the two groups. RESULTS: There was no difference in age and diseased coronary artery branches between the two groups. There were more male patients in TF group: Male-to-female ratios of TF and MIBI groups were 78:37 and 23:22, respectively (p<0.05). The overall sensitivity of TF study was 92% and specificity 36%. The overall, sensitivity and specificity of MIBI study were 93% and 30% respectively. There was no difference between TF and MIBI groups in identifying individual diseased coronary artery branches. CONCLUSION: One day stress-rest myocardial SPECT using either TF or MIBI was comparable and was a very sensitive test in detecting coronary artery disease.