Heart rate variability in patients presenting with anginal symptoms in absence of cardiac and other diseases

Objectives: Angina is a symptom of coronary artery disease (CAD). Modulation of cardiac autonomic tone as assessed by heart rate (HR) variability (HRV) is found reduced in patients with CAD; myocardial ischemia, myocardial infarction and some other cardiovascular diseases. Reduced HRV has been found associated with sudden cardiac death in these CAD patients. Several patients present with anginal symptoms clinically in absence of CAD or other diseases. The status of HRV is not much clear in these patients. Thus, we aimed to assess HRV in patients with angina with and without myocardial ischemia and compare it with HRV of healthy subjects of similar age groups and follow-up patients for 1 year for cardiac/health events. Materials and Methods: The study included 61 consecutive male patients clinically presenting with angina and 30 healthy subjects. Based on Thallium-201 myocardial perfusion Single-photon emission computerized tomography (SPECT) imaging, patients were divided into two groups; patients with myocardial perfusion defects (MPD), (n = 33, age 54.91 ± 7.43 years) and patients with no MPD (NMPD), NMPD (n = 28, age 53.04 ± 8.50 years). Short-term HRV was assessed in all patients and subjects in resting supine position following standard protocol. All MPD and 25 NMPD patients could be followed up for 1 year for cardiac/health events. Results: Surprisingly, the NMPD patients showed significantly reduced HRV, Standard deviation of the N-N intervals, The square root of the mean squared differences of successive N-N intervals, Percentage of the number of interval differences of successive N-N intervals greater than >50 ms divided by total number of R-R intervals, low frequency (LF) power, High Frequency (HF) power and total power as compared to both MPD patients and healthy subjects. (Total power [NMPD vs. MPD]: 610.1 [379.9–1072.8] vs. 1508.0 [748.4–2339.4] millisecond squares (ms2 ), P = 0.001), healthy subjects (Total power: 1414.6 [1104.6-2141.5] ms2 , P = 0.001). The markers of sympathetic tone; LF (normalised unit) and LF/HF ratio were higher in NMPD patients as compared to MPD patients resulting in an altered sympathovagal balance. During a 1-year follow-up, sudden death was seen in one MPD patient (3.1%) and two NMPD patients (8%). Conclusion: The NMPD patients showed significantly reduced HRV as compared to both MPD patients and Healthy subjects with an altered sympathovagal balance. Sudden death was also seen in NMPD patients as MPD patients.

Assessment of Left Ventricular Ejection Fraction by Thallium-201 Myocardial SPECT-CT in Patients with Angina Pectoris: Comparison with 2D Echocardiography / 대한핵의학회잡지

PURPOSE: Left ventricular (LV) ejection fraction (EF) is an important parameter for assessing cardiac systolic function and predicting prognosis in patients with cardiovascular disease. The aim of this study was to evaluate the feasibility of assessing LVEF by Tl-201 hybrid myocardial single-photon emission computed tomography (SPECT)/CT using two attenuation correction methods in patients with angina pectoris.METHODS: A total of 339 patients with angina pectoris (62.8 ± 12.9 years, male:female = 206:133) were analyzed. All patients underwent Tl-201 myocardial SPECT/CT and transthoracic two-dimensional (2D) echocardiograph. We compared LVEF assessed by SPECT/CT using two attenuation correction methods: CT-based attenuation correction (CTAC) and non-attenuation correction (non-AC) methods and 2D echocardiography.RESULTS: LVEF assessed by either of the two attenuation correction techniques and 2D echocardiography showed moderate correlation in all patients with angina pectoris (r = 0.487 for CTAC and r = 0.473 for non-AC, p < 0.001). Results were similar in the subgroup of patients with perfusion abnormalities on myocardial SPECT/CT images. Overall diagnostic performances were similar for the CTAC and non-AC methods for evaluating normal and decreased LVEF by myocardial SPECT/CT.CONCLUSION: LVEF measured by the CTAC method of Tl-201-gated myocardial SPECT/CT was comparable with the conventional non-AC method in patients with angina pectoris and in the subgroup of patients with perfusion abnormality. Tl-201-gated myocardial hybrid SPECT/CT can be a reliable tool in the assessment of LVEF in clinic.

Evaluación de la recurrencia de tumores musculoesqueléticos mediante gammagrafía complementada con SPECT/CT con talio-201 en población pediátrica / Evaluation of recurrence of musculoskeletal tumors with thallium-201 scintigraphy plus SPECT/CT in pediatric population

Resumen Introducción: Los estudios de imagen, como la tomografía simple y contrastada, son la primera aproximación diagnóstica para detectar la recurrencia de tumores musculoesqueléticos. El objetivo de este estudio retrospectivo fue demostrar la utilidad de la gammagrafía acoplada a tomografía computarizada por emisión de fotón único (SPECT/CT) con talio-201(201Tl) en la valoración de tumores musculoesqueléticos malignos con sospecha de recurrencia o enfermedad metastásica. Métodos: Se realizaron 72 estudios gammagráficos y de SPECT/CT para la valoración de la recurrencia locorregional y a distancia, al menos 8 semanas tras la última terapia, en 42 pacientes con diferentes tipos de tumores musculoesqueléticos malignos, como osteosarcoma, sarcoma de Ewing, rabdomiosarcoma, retinoblastoma, sarcoma sinovial y tumor de Wilms en el Hospital Infantil de México. Se calcularon el valor predictivo positivo (VPP) y el intervalo de confianza del gammagrama y de la SPECT/CT en comparación con el resultado del análisis histopatológico y el seguimiento clínico y radiológico para identificar la recurrencia. Resultados: La gammagrafía fue anormal en 30 (71.4%) de los 42 pacientes. Se detectaron 33 lesiones (30 pacientes) por gammagrafía y 25 (21 pacientes) por telerradiografía de tórax y tomografía de dos regiones. La SPECT/CT se realizó en 30 pacientes y se detectaron 12 lesiones adicionales al rastreo planar. El VPP con la gammagrafía fue del 82%, y con la SPECT/CT, del 100%. Conclusión: La gammagrafía con 201Tl puede considerarse un estudio adecuado para identificar los sitios de viabilidad tumoral, con alto grado de certeza diagnóstica al complementar con SPECT/CT.

Abstract Background: Imaging studies, particularly simple and contrast-enhanced tomography, constitute the first diagnostic approach to detect recurrence of musculoskeletal tumors. The aim of the present retrospective study was to demonstrate the usefulness of scintigraphy plus SPECT/CT (single photon emission computed tomography) with thallium-201 (201Tl) in the evaluation of malignant musculoskeletal tumors with suspicion of recurrence or metastatic disease. Methods: Eight weeks after the last therapy, 72 scintigraphy and SPECT/CT studies were performed to assess regional recurrence and metastatic disease in 42 patients with different types of malignant musculoskeletal tumors, such as osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, retinoblastoma, synovial sarcoma, and Wilms tumor at the Hospital Infantil de México Federico Gómez. The positive predictive value (PPV) and the confidence interval of the scintigraphy and SPECT/CT were calculated when compared with the results of the histopathological analysis and the clinical and radiological follow-up for the identification of recurrence. Results: Scintigraphy was abnormal in 30 (71.4%) of the 42 patients; 33 lesions (30 patients) were detected by scintigraphy and 25 lesions (21 patients) by chest X-ray and tomography of two regions. The SPECT/CT was performed on 30 patients, where 12 lesions were detected in addition to the planar scintigraphy. Scintigraphy showed a PPV of 82%; SPECT/CT, 100%. Conclusion: 201Tl-scintigraphy can be considered as an adequate study to identify the sites of tumor viability with a high degree of diagnostic certainty combined with the SPECT/CT technique.

Evaluation of a novel decorporation approach to prevent radioactivity uptake by using acidosis in experimental animals.

With an aim to devise a prophylactic and/or therapeutic approach for preventing internalization of radiothallium (201Tl), and more importantly by implication, its chemical analogue radiocesium (137Cs) during any nuclear emergency, different ex vivo and in vivo animal models were created to determine the role of pH in absorption of 201Tl across jejunum/muscle tissue and whole body retention of 201Tl respectively. Movement of Tl+ under simulated pH conditions proved that pH had direct influence on its absorption. Oral intake of acidified water or parenteral administration of lactic acid was able to reduce the body burden of 201Tl by up to 12 and 50% respectively. The results indicate that acidification of gut, within physiological range may be used as an option for decorporation/inhibition of incorporation of radiothallium and radiocesium, particularly in cases of mass casualty.

Transient cell function disruption by low dose acute exposure of ionizing radiation.

Incubation of BMG-1 cells with thallium chloride (201Tl) in the range of diagnostic dose did not show a smooth uptake curve and appeared to have an unsuspected deviation in initial phase. In the present study this unexpected phenomenon was explored, using commonly used radionuclides (viz., 201Tl and 131I). Comparison was made with technetium-99m pertechnetate (99mTcO4-) and technetium-99m labeled methoxyisobutylisonitrile (99mTc-MIBI) that are known to show conventional 2 phase graph representing inflow and outflow segments. Serial in vitro, ex-vivo and in vivo gamma scintigraphy as well as NMR spectroscopy experiments were conducted to corroborate the results. BMG-1 cells demonstrated a four-phase uptake pattern with 201Tl as compared to a conventional biphasic pattern with 99mTc-MIBI. Flow cytometry data however did not reveal any 201Tl induced cell injury. Further, mice tissue extracts injected with 201Tl also showed a transient depression in its uptake. Scintigraphy experiments in rabbits administered with diagnostic dose of 201Tl and 131I confirmed the in vitro and ex vivo findings. Further, proton NMR spectroscopy showed decrease in the level of choline at 3 h and 24 h in 201Tl treated animals as compared to control. Phosphoethanolamine peak firstly decreased at 3 h but reached normal level at 24 h time point. No significant change was observed in the level of betaine. This transient reduction in internalization of 201Tl and 131I may represent a hitherto unknown acute effect of low dose radiation, i.e., transient depression in Na+-K+ ATPase pump activity without any apparent evidence of cell damage, representing a transient cell membrane dysfunction. The phenomenon may present a mechanistical explanation of ‘thyroid stunning’ at cellular level and suggest that it may be more universal in nature than suspected till now.

Assessment of coronary artery disease with the nitroglycerin augmented ~(99m)Tc-MIBI and ~(201)Tl dual-isotopic myocardial perfusion imaging / 中国医学影像技术

Objective To assess the clinical value of dobutamine 201Tl stress-redistribution/nitroglycerin augmented ~(99m)Tc-metho~(99m)Tc-xyisobutylisonitrile (MIBI) gated myocardial perfusion imaging (MPI) in patients with coronary artery disease (CAD). Methods A total of 132 patients with suspected CAD underwent dobutamine 201Tl stress-redistribution/nitroglycerin augmented MIBI gated MPI and coronary arteriography (CAG) within two weeks after MPI. Percutaneous coronary interventions (PCI) were performed in 23 patients with myocardial infraction. The regional wall movement was assessed with echocardiography before and within three months after PCI. Results Taking stenosis ≥50% as standard of CAD, the sensitivity, specificity and accuracy of dual-isotopic SPECT imaging in diagnosing CAD was 93.41%, 87.80% and 91.67%, respectively. The sensitivity, specificity and accuracy in diagnosing left anterior descending artery (LAD) stenosis was 93.85%, 91.04% and 92.42%, for left circumflex artery (LCX) was 86.79%, 89.87% and 88.64%, while for right coronary artery (RCA) was 81.25%, 82.14% and 81.82%, respectively. Of all 207 myocardium segments in 23 patients with myocardial infarction, radioactivity defect was found in 113 segments on the redistributed ~(201)Tl images, and radiofilling was found in 52 (52/113) segments on the nitroglycerin augmented ~(99m)Tc-MIBI images, whereas 61 segments had no radiofilling. Taking regional wall movement improvement as the criterion of viable myocardium, the sensitivity, specificity and accuracy of identifying viable myocardium with nitroglycerin augmented ~(99m)Tc-MIBI imaging was 87.23%, 83.33% and 84.96%. Conclusion Dobutamine ~(201)Tl stress-redistribution/nitroglycerin augmented ~(99m)Tc-MIBI gated MPI is able to effectively detect CAD and viable myocardium and helpful in diagnosis and treatment of CAD.

Stress Testing and Imaging Protocols for Myocardial Perfusion Studies / 핵의학분자영상

Scince 201Tl was introduced as a myocardial perfusion imaging agent in the early 1970s, scintigraphic evaluation of myocardial perfusion for the diagnosis of coronary artery disease is a valuable noninvasive diagnostic imaging modality. Stress radionuclide myocardial perfusion imaging is widely accepted to have high diagnostic and prognostic use in the assessment of patients with known or suspected coronary artery disease. With wise use of this nonivasive imaging technique, more patients are referred for stress perfusion imaging. Until now various protocols for stress testing and myocardial imaging were developed and used in worldwide. This article presented various protocols of stress testing and myocardial imaging for clinical use.

Trazabilidad de las mediciones realizadas con activímetros en medicina nuclear / Traceability of radionuclide calibrators measurements in nuclear medicine

RESUMEN En medicina nuclear, las dosis del radiofármaco administradas se expresan mediante la actividad del radionucleido en el preparado. La medición de esa actividad se realiza en el activímetro y resulta primordial para garantizar la comparabilidad nacional e internacional de los resultados clínicos relacionados y la seguridad radiológica del paciente. En este trabajo se detalla la transferencia de la unidad becquerel a los activímetros empleados en medicina nuclear en Cuba. Se presentan los resultados de la implantación de un servicio de calibración in situ, basado en la comparación directa con muestras de referencia de los radionucleidos específicos sujetos a medición. Los resultados de las comparaciones de medición internacionales y nacionales que se muestran, validan los estimados de incertidumbre de los coeficientes de calibración, determinados para la medida en estos instrumentos de la actividad de los principales emisores gamma que se han utilizado en la medicina nuclear cubana: technetium 99,iodine 131, radiopharmaceuticals thallium 201.

ABSTRACT In nuclear medicine, the administered doses of the radiopharmaceutical are expressed through the amount of radioactivity contained in the drug. The measurement of this activity, performed using a radionuclide calibrator, is of the utmost importance to guarantee the national and international comparability of clinic results and the radiological safety of the patient. In this paper, the transferring of the becquerel unit to the radionuclide calibrators employed in the nuclear medicine practice in Cuba is detailed. The obtained results with an in situ calibration service, which is based on the direct comparison with standards of the specific measured radionuclides, are presented. Outcomes of international and national measurement comparisons are shown. They validate the uncertainty estimates of the calibration coefficients installed in the instruments for measurements of technetium 99,iodine 131, radiopharmaceuticals thallium 201, the main gamma emitters that have been used in Cuban nuclear medicine.

Relationship between The Expressions of Sodium/Iodide Symporter and The Findings of Thallium-201 Scan in Thyroid Nodules / 대한내분비학회지

BACKGROUND: The sodium/iodide symporter (NIS) has an important role in the diagnosis and treatment of well differentiated thyroid carcinoma. The relationship between the uptake of thallium- 201 scan (201Tl scan) and the expression of sodium/iodide symporter (hNIS) was studied in thyroid nodules. METHODS: Patients that had undergone operations for thyroid nodules, and who received a 201Tl scan before their operations, were investigated. Anti-NIS antibodies were used to analyze the presence and distribution of the hNIS protein by immunohistochemical staining of their thyroid tissues. RESULTS: Forty-four patients (papillary carcinoma; 18, follicular adenoma; 11, adenomatous goiter; 14, nonspecific thyroiditis; 1) 30 with no immunoreactivity and 14 with a positive reaction to the anti-NIS antibody, were included. The NIS negative patients (12/30) had no 201Tl uptake, but all others were positive on 201Tl scan, and the NIS-positive patients (13/14) had positive 201Tl uptake, with 1 negative on 201Tl scan, with significant difference (p=0.035). Of the 18 patients with a papillary thyroid carcinoma, the NIS negative patients (2/10) had no 201Tl uptake and the others were positive on 201Tl scan, but without significant difference. NIS positive patients (1/8) with a papillary thyroid carcinoma had no 201Tl uptake, and the others were positive on 201Tl scan, but without significant difference. Whether the results of NIS staining and 201Tl scan were positive or not did not affect the responses of radioactive iodine therapy in our study. CONCLUSION: These results suggest that thallium-201 uptake may be correlated with hNIS expression in thyroid nodules

Predicting the Response of Preoperative Chemotherapy in Osteosarcoma by Thallium-201 Scintigraphy / 대한정형외과학회잡지

PURPOSE: The current study was designed to evaluate the ability of thallium-201 scintigraphy to predict the response to preoperative chemotherapy in osteosarcoma, by comparing changes in thallium uptake ratio after chemotherapy to the tumor necrosis ratio. MATERIALS AND METHODS: Twelve osteosarcoma patients were included in this study. Thallium-201 scintigraphy was performed before and after preoperative chemotherapy, and the degree of tumor necrosis was estimated by histologic mapping postoperatively. To quantitatively determine thallium uptake, we drew a region of interest on the tumor side and on the contralateral normal side as a mirror image, and calculated the uptake ratio with dividing the gamma count in the tumor side by that of the normal side. We calculated these percent changes of thallium uptake ratio in the early and delayed phases, and compared these to the corresponding tumor necrosis ratio. RESULTS: Percent changes in the thallium uptake ratio were found to be correlated with the tumor necrosis ratio (p<0.03). This correlation was found in both the early (p<0.03) and delayed phase (p<0.03); moreover the correlation coefficient in early phase (0.79) was greater than that in the delayed phase (0.67). CONCLUSION: Thallium-201 scintigraphy could be effective at predicting the response to preoperative chemotherapy in osteosarcoma.

The Role of Thallium-201 Scintigraphy in Bone and Soft Tissue Tumor / 영남의대학술지

Thallium-201 scintigraphy is used to discriminate the malignant bone tumor from the benign by qualitatively and quantitatively, and to predict the response of preoperative chemotherapy in osteosarcoma, by comparing the changes of thallium uptake ratio after chemotherapy to the tumor necrosis ratio. Thallium-201 scintigraphy scan should be done prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator is usually used for scanning. The patient is injected with 2-3mCi of Tl-201 and the early phase is checked in 30 minutes and delayed phase in 3 hours. The scan images are visually evaluated by a blinded nuclear medicine physician. We could evaluate true positive, true negative, false positive and false negative by the comparison of results with those of biopsy, and calculate positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%). For the quantitative analysis of thallium uptake, we drew the region of interest on the tumor side and contralateral normal side as mirror image, and calculated the uptake ratio with dividing the amount of gamma count in tumor side by normal side. We could calculate the percent changes of thallium uptake ratio in early and delayed phase, and compare them to the ratio of tumor necrosis. Thallium-201 scintigraphy proved as useful imaging study to discriminate malignant bone tumor from benign, but had exception in giant cell tumor and low grade malignant bone tumors. We can use T1-201 scan to differentiate the benign from the malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

The Role of Thallium-201 Scintigraphy in Bone and Soft Tissue Tumor / 영남의대학술지

Thallium-201 scintigraphy is used to discriminate the malignant bone tumor from the benign by qualitatively and quantitatively, and to predict the response of preoperative chemotherapy in osteosarcoma, by comparing the changes of thallium uptake ratio after chemotherapy to the tumor necrosis ratio. Thallium-201 scintigraphy scan should be done prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator is usually used for scanning. The patient is injected with 2-3mCi of Tl-201 and the early phase is checked in 30 minutes and delayed phase in 3 hours. The scan images are visually evaluated by a blinded nuclear medicine physician. We could evaluate true positive, true negative, false positive and false negative by the comparison of results with those of biopsy, and calculate positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%). For the quantitative analysis of thallium uptake, we drew the region of interest on the tumor side and contralateral normal side as mirror image, and calculated the uptake ratio with dividing the amount of gamma count in tumor side by normal side. We could calculate the percent changes of thallium uptake ratio in early and delayed phase, and compare them to the ratio of tumor necrosis. Thallium-201 scintigraphy proved as useful imaging study to discriminate malignant bone tumor from benign, but had exception in giant cell tumor and low grade malignant bone tumors. We can use T1-201 scan to differentiate the benign from the malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

Prediction of Salvaged Myocardium in Patients with Acute Myocardial Infarction after Primary Percutaneous Coronary Angioplasty using early Thallium-201 Redistribution Myocardial Perfusion Imaging / 대한핵의학회잡지

PURPOSE: The amount of salvaged myocardium is an important prognostic factor in patients with acute myocardial infarction (MI). We investigated if early Tl-201 SPECT imaging could be used to predict the salvaged myocardium and functional recovery in acute MI after primary PTCA. MATERIALS AND METHODS: In 36 patients with first acute MI treated with primary PTCA, serial echocardiography and Tl-201 SPECT imaging (5.8+/-2.1 days after PTCA) were performed. Regional wall motion and perfusion were quantified with on 16-segment myocardial model with 5-point and 4-point scaling system, respectively. RESULTS: Wall motion was improved in 78 of the 212 dyssynergic segments on 1 month follow-up echocardiography and 97 on 7 months follow-up echocardiography, which were proved to be salvaged myocardium. The areas under receiver operating characteristic curves of Tl-201 perfusion score for detecting salvaged myocardial segments were 0.79 for 1 month follow-up and 0.83 for 7 months follow-up. The sensitivity and specificity of Tl-201 redistribution images with optimum cutoff of 40% of peak thallium activity for detecting salvaged myocardium were 84.6% and 55.2% for 1 month follow-up, and 87.6% and 64.3% for 7 months follow-up, respectively. There was a linear relationship between the percentage of peak thallium activity on early redistribution imaging and the likelihood of segmental functional improvement 7 months after reperfusion. CONCLUSION: Tl-201 myocardial perfusion SPECT imaging performed early within 10 days after reperfusion can be used to predict the salvaged myocardium and functional recovery with high sensitivity during the 7 months following primary PTCA in patients with acute MI.

A case of coronary fistula between the left anterior descending and main pulmonary artery complicating acute myocardial infarction in a 27-year-old man / 대한내과학회지

We report a case of coronary fistula between the left anterior descending and main pulmonary artery complicating acute non-Q wave myocardial infarction. A 27-year-old man visited emergency department because of severe chest pain lasting two hours. The electrocardiogram showed ST segment elevation in precordial leads V3~6. Cardiac enzymes were as follows;CK-MB:36.44 IU/L T-T:0.489 ng/mL, CPK:542 IU/L, and LDH:475 IU/L. The thallium-201 dipyridamole stress perfusion scan showed perfusion defect and reversed redistribution in the anteroseptal wall. The coronary angiogram revealed coronary artery fistula between the proximal left anterior descending artery and main pulmonary artery without significant stenoses of coronary arteries. The result of ergonovine test was negative. After micro-coil embolization to the coronary fistula, symptoms were improved. Follow-up thallium-201 scan showed normalized blood flow in the left anteroseptal wall.

Thallium-201 SPECT in the Evaluation of Postoperative Tumor Recurrence on the Chest Wall in Lung Cancer / 결핵

No abstract availalbe.

Usefulness of Thallium-201 Scintigraphy for Differentiating Benign and Malignant Thyroid Nodules in Inconclusive Cases with Fine Needle Aspiration / 대한내분비학회지

BACKGROUND: Although fine needle aspiration(FNA) is recognized as the most accurate procedure in the differential diagnosis of thyroid nodules, about 20~30% of nodules remain inconclusive in FNA. Therefore, we assessed the usefulness of Thallium-201 scintigraphy in differentiating benign from malignant thyroid nodules in patients with inconclusive diagnosis by FNA. METHODS: We studied 43 patients with inconclusive diagnosis(29 of follicular neoplasm, 11 of cystic change and 3 of inadequate) by FNA, with the results being confirmed histopathologically by operation. Thallium-201 scintigraphy was performed at 15 minutes(early scan) and 2-3 hours(late scan) after the intravenous administration of 37 MBq of thallium-201. Malignant nodules were defined by the retention of Thallium-201 on delayed images. RESULTS: In the 43 patients with inconclusive FNA diagnosis, Thallium-201 scan had a sensitivity of 75.0%, specificity of 62.9% and accuracy of 65.1%. The positive and negative predictive values were 31.6% and 91.7%, respectively. In the 29 patients with follicular neoplasm by FNA, Thallium-201 scan had a sensitivity of 83.3%, specificity of 60.9% and accuracy of 65.5%. The positive and negative predictive values were 35.7% and 93.3%, respectively. CONCLUSION: In particular, Thallium-201 scintigraphy demonstrated a high negative predictive value, Therefore, for patients with inconclusive FNA findings, Thallium-201 scintigraphy might be useful in differentiating between benign and malignant thyroid nodules, and has the potential to reduce the rate of unnecessary operations in benign nodules.

The study of the shunt index of thallium-201 liver scintigraphy and liver biopsy in the patients with chronic liver disease / 대한내과학회지

BACKGROUND: The disturbances of portal circulation in chronic liver disease may cause hepatic failure, hepatic encephalopathy and variceal bleeding. The measure of porto-systemic shunt plays a significant role in the management and prognosis of the patients. So we have evaluated the relationship between the shunt index of thallium-201 liver scan and the histological grade and stage of chronic liver disease. METHODS: The thallium-201 scintigraphy per rectum was evaluated in 159 patients with chronic liver disease, which were proven with percutaneous liver biopsy. We used the heart to liver activity ratio at 20 minute as shunt index, representing portal-systemic shunt. The two pathologists scored independently hepatitis activity (lobular and porto-periportal activity) and stage (fibrosis). RESULTS: A significant difference was noted between the shunt index and the scores of fibrosis (p< 0.001) although this correlation was statistically weak (r=0.26, p=0.008). In cumulative logistic regression test, the shunt index had a effect on the fibrosis (p< 0.001) but not on the lobular and porto-periportal activity. Fibrosis was predicted as less than 2 if shunt index was less than 0.24, 3 if more than 0.24 but less than 0.46, 4 if more than 0.46. CONCLUSION: The shunt index of thallium-201 liver scintigraphy correlated only with fibrosis not with lobular and porto-periportal activity. As the fibrosis progresses in chronic liver disease, portal hypertension becomes more severe and the shunt index increases. Thallium-201 liver scan may be useful for evaluation of hepatic fibrosis instead of invasive liver biopsy in predicting the histological stage (fibrosis) of advanced chronic liver disease.

Thallium-291 Whole Body Scintigraphy in Postoperative Follow-up of Differentiated Thyroid Carcinoma / 대한내분비학회지

BACKGROUND: The advantages of thallium (Tl)-201 whole body scan in follow-up of patients with thyroid carcinoma include no need to discontinue thyroid hormone replacement, a shorter period of time between injection and imaging, a lower radiation dose, and preservation of affinity for subsequent therapeutic dose of 131I. To evaluate the reliability of whole body scintigraphy using Tl-201 in postoperative follow-up of thyroid carcinoma, this procedure was performed in patients after total thyroidectomy for thyroid carcinoma. The results were compared with those of 131I scintigraphy. METHODS: One hundred nineteen cases (119 patients) with a median age of 43 years (range, 20 85 years) were included in the study. After optimal endogenous thyroid-stimulating hormone stimulation (>50 mIU/mL), 131I (4 mCi) scan and Tl 201 (3 mCi) scan were simultaneously performed. Concomitantly serum thyroglobulin and anti-thyroglobulin antibody levels were checked. If abnormal findings on any of the scintigraphic methods or high levels of thyroglobulin (> 10 ng/mL) were detected, high dose (150~200mCi) 131I was administered as therapy and then whole body scans were performed repeatedly after the therapy. The presence or absence of thyroid cancer was established by pathologic, radiologic, and/or high dose 131I scan findings. RESULTS: In 12 patients, ll-201 scan revealed positive accumulations which were not found on 131I scan, of whom 9 had elevated thyroglobulin levels. In these cases, 5 cases were interpreted to have normal thyroid remnant and 7 cases showed pathologic findings (1 lung, 2 lymph node, 1 bone, and 2 lung and lymph node metastasis, and 1 false positive accumulation of thallium). Metastasis were confirmed histologically in 2 and radiologically in 5 cases. Negative Tl-201 scans, despite of positive 131I scans, occurred in 20 patients, of whom 6 had abnormal thyroglobulin levels. Seventeen cases were interpreted to have thyroid remnant, 2 cases were diagnosed to have thyroid carcinoma metastasis (1 lung, 1 lung and lymph node), and 1 case was not confumed. CONCLUSION: These results suggest that 131I scan is superior to 11-201 scan for detection of residual or metastatic differentiated thyroid carcinoma. However, the use of combined modalities may provide a higher diagnostic yield. TI-201 scan can be useful especially in cases in which 'I scan is negative despite of abnormal thyroglobulin levels.

Diagnostic Ability of Arm Exercise Thallium-201 SPECT in Detecting Coronary Artery Disease

BACKGROUND: Exercise testing is a standard noninvasive method used in the evaluation and management of patients with suspected coronary artery disease. However, patients with lower limb impairment are unable to undergo a standard bicycle or treadmill test. Alternative methods of exercise testing are needed for patients with vascular, orthopedic or neurologic conditions who cannot perform leg exercise. This study was aimed to determine the diagnostic accuracy of arm exercise thallium-201 SPECT for evaluating chest pain in patients unable to perform leg exercise. METHOD: Twenty-five anginal patients performed arm ergometry testing in conjunction with thallium-201 SPECT. Thereafter all underwent coronary angiography. RESULT: Significant coronary artery disease (> or =50% stenosis) in at least one vessel was present in 22 (88%) of the 25 patients. The sensitivity of thallium-201 SPECT for detecting coronary artery disease was 91%, which was significantly higher than the 32% sensitivity found with the electrocardiographic response alone (p <0.001). Thallium-201 SPECT yielded a sensitivity of 88, 86 and 100% for one, two, and three vessel diseases, respectively, and an 84% sensitivity and 81% specificity for detecting individual vessel stenosis. CONCLUSION: Arm exercise thallium-201 SPECT is useful for detecting coronary artery disease in patients unable to perform leg exercise. In addition, it provides an information regarding exercise tolerance. Therefore, this test appears to be reliable and useful and should be considered in the detection of coronary artery disease in nonambulatory patients.

Accumulation of Thallium-201 in Hemorrhagic Cerebral Infarction / 대한핵의학회잡지

Thallium-201 brain SPECT is utilized in the diagnosis of brain tumor especially in cases where CT or MRI findings alone cannot differentiate malignant lesion from benign. Recently we came across two cases of positive T1-201 brain SPECT in clinically suspected brain tumor patients that turned out to be hemorrhagic cerebral infarction instead on biopsy. The findings in these cases demonstrate that thallium-201 accumulation may occur by the breakdown of the blood-brain barrier and phagocytic cell infiltration in the liquefaction stage of infarction.