Thallium-201 SPECT Research Articles

Value of Thallium-201 SPECT and SPECT/CT Brain Imaging in Differentiating Malignant from Nonmalignant Lesions: A Comparative Case-Series Study with Pathologic and/or Clinical Correlation (P3-13.005)

<h3>Objective:</h3> To describe results of patients who underwent Thallium-201 Single-photon Emission Computed Tomography and Computed Tomography (SPECT/CT) Brain Imaging and relate it to clinical and/or histopathologic findings. This is the first study in the Philippines that documented the correlation between Thallium-201 SPECT/CT findings with histologic and/or clinical diagnosis. <h3>Background:</h3> Thallium-201 SPECT/CT brain scanning is an imaging modality which can be done to differentiate between malignant and non-malignant lesions. Despite its availability, the procedure has been under-utilized and the lack of knowledge about its potential use can be the significant barrier in maximizing its clinical utility. <h3>Design/Methods:</h3> This is a retrospective case series study of 10 patients with cerebral lesions who underwent Thallium-201 SPECT/CT brain imaging in a hospital in the Philippines from 2010 to 2021. <h3>Results:</h3> From 2010 to 2021, a total of 10 patients underwent Thallium-201 SPECT/CT brain scan. Six had negative results while 4 had positive results. All of the patients who had positive results were found to have malignancy, whether recurrent or newly diagnosed. All of the patients with negative scan were found to have either an infectious and inflammatory disease and responded to treatment albeit in different degrees. Two of the 10 patients underwent biopsy whose results were consistent with the Thallium-201 SPECT/CT brain scan results. <h3>Conclusions:</h3> The findings in this study support the role of thallium scintigraphy in the diagnosis of patients with brain lesions most significantly when there is a need to differentiate between a malignant and benign condition. Thallium scintigraphy is a more affordable option compared to Magnetic Resonance Imaging whether conventional or combined with spectroscopy or perfusion studies. In the Philippine setting where cost can be an important factor in the choice of diagnostic procedure, this study further supports the use of Thallium-201 SPECT/CT scan in the diagnosis of patients with brain lesions. <b>Disclosure:</b> Dr. Pang has nothing to disclose. Dr. Luistro has nothing to disclose. Christianne Mojica has nothing to disclose. Dr. Domingo has nothing to disclose. Dr. Batara has nothing to disclose.

Value of Thallium-201 SPECT and SPECT/CT Brain Imaging in Differentiating Malignant From Nonmalignant Lesions: A Comparative Case-Series Study With Pathologic and/or Clinical Correlation.

Thallium-201 single-photon emission computed tomography/computed tomography (SPECT/CT) brain scan is an imaging modality which can be done to differentiate between malignant and nonmalignant lesions among patients with nonconclusive findings on conventional neuroimaging. This study describes the results of thallium-201 SPECT/CT brain imaging and relate it to histopathologic and/or clinical findings and evaluate the value of thallium-201 SPECT/CT brain imaging in differentiating malignant from nonmalignant lesions. This is a retrospective case series study of 10 patients with cerebral lesions who underwent thallium-201 SPECT/CT brain imaging in a hospital in the Philippines from 2010 to 2021. A total of 10 patients underwent thallium-201 SPECT/CT brain scan. Six had negative results while 4 had positive results. All of the patients who had positive results were found to have malignancy, whether recurrent or newly diagnosed. All of the patients with negative scan were found to have either an infectious and inflammatory disease and responded to treatment albeit in different degrees. Two of the 10 patients underwent biopsy whose results were consistent with the thallium-201 SPECT/CT brain scan results. Thallium-201 brain scan combined with SPECT and SPECT/CT has been demonstrated to be useful in distinguishing malignant from nonmalignant lesions and is more cost-effective versus other imaging techniques. The findings in this study support the role of thallium scintigraphy in the diagnosis of patients with brain lesions most significantly when there is a need to differentiate between a malignant and benign condition.

Value of Thallium-201 SPECT and SPECT/CT Brain Imaging in Differentiating Malignant from Nonmalignant Lesions: A Comparative Case-Series Study with Pathologic and/or Clinical Correlation

Value of Thallium-201 SPECT and SPECT/CT Brain Imaging in Differentiating Malignant from Nonmalignant Lesions: A Comparative Case-Series Study with Pathologic and/or Clinical Correlation

333P - Study of searching on efficacy of immune checkpoint inhibitor for the non-small cell lung cancer using FDG-PET/CT and thallium SPECT

BackgroundFDG-PET/CT and Thallium SPECT (TL) which are radioisotope examination are inspection used as diagnostic imaging in the malignant tumors conventionally, and it is reported when useful for a stage diagnosis of the lung cancer. It was common to use the CT imaging according to the RECIST criteria for the effect judgment of cytotoxic agents and molecular target agents. In determining the efficacy of immune checkpoint inhibitors (ICIs), we often experienced that the assessment on CT imaging and the true effect do not match. Therefore, we planned a prospective study to evaluate whether FDG-PET/CT and TL examination is useful for ICI effect judgment. We examined the correlation between SUV differences on PET examination before treatment and 2 months after treatment initiation and RECIST evaluation. MethodsA total of 18 advanced NSCLC patients treated at Kansai Medical University Hospital from September 2017 to September 2018 using ICI monotherapy were enrolled in this study. We examined the correlation with a PERCIST response rate and the response rate that went to the CT evaluation using RECIST1.1. ResultsThe median age was 74 years. There were 15 men and three women. 15 cases were evaluable both before and two months after treatment initiatoin. There were CR/PR/SD/PD;0/3/7/5 by RECIST evaluation, and the curative effect judgment by FDG-PET were CMR/PMR/SMD/PMD; 1/3/6/5. 1 case was PD in RECIST, but was PMR in FDG-PET.The PR case tended to be higher in Tl accumulation after the treatment than an SD and PD cases. ConclusionsThe effect measurement by FDG-PET showed usefulness with more than that of RECIST evaluation and Tl-SPECT seems to have the potential to be useful in determining the effect of ICIs. Legal entity responsible for the studyTakayasu Kurata. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

P297Assessment of left ventricular volumes and ejection fraction by ultra-low-dose thallium SPECT on CZT camera; a comparison with magnetic resonance

P297Assessment of left ventricular volumes and ejection fraction by ultra-low-dose thallium SPECT on CZT camera; a comparison with magnetic resonance

The Effect of Long Term Smoking as an Independent Coronary Risk Factor on Myocardial Perfusion Detected by Thallium 201 or Tc99m Sestamibi Spect Study

Objective: The aim of this work was to assess the effect of smoking as an independent coronary risk factor on Myocardial Perfusion detected by Thallium 201 or Tc99m Sesta MIBI SPECT study.Methods: This study included 200 patients, 100 who are smokers only (group A) without any cardiac risks and the other 100 (group B) were nonsmokers, but with single cardiac risk factor as hypertension or diabetes. Each was subjected to Dipyridamole (smokers 53, 47) or exercise (nonsmokers 51, 49) Thallium-201 or Tc99m SestaMIBI SPECT protocol.Results: Comparing smokers versus nonsmokers who have another one risk factor, smokers had : Lower age with ischemic heart disease 55 years versus 60 years; Higher heart rate during peak stress; higher blood pressure during peak stress; More incidence of chest pain during stress test; had the same degree of ischemic perfusion defect, but higher incidence of persistent LV dilatation (43% versus 28%), higher incidence of severe perfusion defects (68% versus 53%) and statistically significant higher incidence of scar tissue (52% versus 30%).Conclusion: Smoking is an independent risk factor equal to hypertension and diabetes but smokers has higher incidence of severe perfusion defects and scar.

Direct detection of Left Ventricular Diastolic Dysfunction by Phase image analysis in Gated Thallium SPECT Scan

Direct detection of Left Ventricular Diastolic Dysfunction by Phase image analysis in Gated Thallium SPECT Scan

Prediction of Post-revascularization Ejection Fraction in Patients with Coronory Artery Disease Using Cavity-to-Myocardial Ratio of Thallium Reinjection Image (Multicenter Trial)

Background: We reported the high correlation between cavity-to-myocardial (C/M) count ratio at stress and rest thallium SPECT, and stress-rest EF calculated by MUGA test, this was confirmed by others. This correlation was explained partially by the functional mass. On the other hand, two important prognostic parameters should be considered before any revascularization technique: (1) Identification of viable myocardium and its amount, (2) Prediction of EF improvement post revascularization. Aim of the study: Correlating EF (C/M) on RD and RI image (EFRD & EFRI) image to actual EF (prevascularization EF1) and 1 year post revascularization EF2. Patients and methods: 78 patients with CAD (68 males and 10 females with mean age of 54.2+9 years) had been subjected to: (1) St-RD-RI thallium SPECT with assessment of reversible or fixed perfusion defects and calculation of C/M and consequently the EFC/M at the three settings. (2) Assessment of EF by MUGA at rest pre and 1 year post revascularization EF1 & EF2 respectively. These patients had been subjected to revascularization either by PTCA and stent (23/78 i.e., 29.5%) or by CABG (55/78, i.e., 70.5%). Results: Out of the 1560 myocardial segments (20 segments × 78 patients), 780 (50%) segments had abnormal resting wall motion. 441/780 (56.5%) of these segments were either of normal thallium uptake or with reversible perfusion defects while the rest (43.5%) showed fixed defects. 233/441 (52.8%) of those normal uptake or reversible segments showed recovery of wall motion post revascularization (PRV) while only 29/339 (15.1%) showed similar improvements. EFRI was found higher than EFRD in 44/78 of patients, no change in 23/78 patients and worsened in 11/78 patients with total agreements of 63/78 (80.8%) with EF2. On the other hand, EFRD was matched with EF1 in 64/78 of patients. 30/64 (46.9%) showed higher EF2, 23/64 (35.9%) showed similar EF2 while 11/64 (17.2%) showed lower EF2. The rest of cases 14/78 showed mismatch between EFRD and EF1 with higher values of EFRD. These patients still had higher values of EFRI and EF2 than EFRD. Conclusion: (1) Mismatch between EFRD and EF1 is an indication of presence of stunning myocardium and of good prognosis. (2) EFRI can be used to predict EF2 and so helps on selecting patients who can benefit from revascularization.

Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery.

Radiographic assessment of cerebral metastasis after stereotactic radiosurgery remains a major challenge in neuro-oncology. It is often difficult to distinguish tumor progression from radiation necrosis in this setting using conventional MR imaging. The objective of this study was to compare the diagnostic sensitivity and specificity of different functional imaging modalities for detecting tumor recurrence after stereotactic radiosurgery. We retrospectively reviewed patients treated between 2007 and 2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling, FDG-PET, and thallium SPECT before stereotactic biopsy. Diagnostic accuracy, specificity, sensitivity, positive predictive value, and negative predictive value were calculated for each imaging technique by using the pathologic diagnosis as the criterion standard. Six patients (42%) had tumor progression, while 8 (58%) developed radiation necrosis. FDG-PET and arterial spin-labeling were equally sensitive in detecting tumor progression (83%). However, the specificity of arterial spin-labeling was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of arterial spin-labeling. In our series, arterial spin-labeling positivity was closely associated with the pathologic diagnosis of tumor progression after stereotactic radiosurgery. Validation of this finding in a large series is warranted.

Abstract 19973: Dynamic Thallium-201 SPECT/CT Provides Quantitative Index of Myocardial Flow and Viability: Validation in Porcine Post-Myocardial Infarction Model

Introduction: Thallium-201 (Tl-201) SPECT imaging is routinely used to evaluate relative myocardial perfusion and/or viability. In this study, we have evaluated Tl-201 kinetics in a porcine model of myocardial infarction (MI) with dynamic imaging on a hybrid SPECT/CT system. Methods: Tl-201 SPECT and contrast CT imaging were performed on hybrid SPECT/64-slice CT (GE Discovery NM/CT 570c) in Yorkshire pigs (n=5) one week following a 90 min balloon occlusion of the LAD below the first diagonal branch. Tl-201 (83-158 MBq) was injected after the initiation of a 900s list-mode acquisition. The list-mode data was reconstructed with MLEM using 30 iterations creating 23 frames (12 x 10s; 6 x 30s; 5 x 120s). Reconstructed dynamic SPECT data was analyzed using FlowquantTM semi-automated analysis software with a 1-compartment model. K1 (index of flow) and k2 (index of viability) were assessed within a 17-segment model of the left ventricle. Four segments within the central infarcted LAD territory were compared to six segments of the contralateral inferolateral wall. The same segments were analyzed for wall thickening from ECG-gated contrast CT scans using centerline approach (GE AW Cardiac Function Xpress). Results: K1 was significantly decreased in the MI vs contralateral normal regions (0.52 ± 0.17 vs 0.61 ± 0.16 ml/min/g, p&lt;0.02). K2 an index of tissue viability was significantly increased in the MI region (0.42 ± 0.19 vs 0.32 ± 0.12 /min, p&lt;0.04), reflecting accelerated Tl-201 washout in MI. Wall thickening in the same MI region was significantly decreased (0.33 ± 1.5 mm vs 3.3 ± 1.9 mm, p&lt;0.005). Conclusions: Dynamic Tl-201 SPECT/CT imaging provides a quantitative index of both myocardial flow and viability using a 1-compartment model. This preliminary pre-clinical demonstrates the potential for dynamic Tl-201 SPECT imaging to quantify myocardial viability early post-MI.

PW319 Comparison of Thallium-201 and 99mTc-Tetrofosmin myocardial perfusion SPECT in patients with triple vessel disease

PW319 Comparison of Thallium-201 and 99mTc-Tetrofosmin myocardial perfusion SPECT in patients with triple vessel disease

Transcatheter treatment for refractory angina with the coronary sinus Reducer

To evaluate the clinical efficacy of the coronary sinus (CS) Reducer in attenuating angina severity in patients suffering from severe refractory angina. Patients with refractory angina, objective evidence of myocardial ischaemia and no option for revascularisation were treated with CS Reducer implantation at two medical centres. Six-month follow-up evaluation consisted of clinical assessment of angina severity. Objective assessment of ischaemia at six-month follow-up was performed in one of the two centres. Successful CS Reducer implantation was achieved in 21 of 23 eligible patients, at both centres. No device-related adverse effects were observed during the procedure or the follow-up period. Canadian Cardiovascular Society (CCS) score diminished from a mean of 3.3 at baseline to 2.0 at six months (n=20, p<0.01), exercise duration was prolonged from 3:16 to 5:16 min (min:sec; n=8, p=0.05). Thallium SPECT summed stress score and summed difference score were both reduced (n=9, 21.5±10 vs.13.2±9, p=0.01, and 11.1±6 vs. 4.7±4, p=0.007, respectively). Wall motion score index at peak dobutamine infusion was also significantly improved (n=8, 1.9±0.4 vs. 1.4±0.4, p=0.046). CS Reducer implantation was safe and resulted in significant improvement of angina class. The results of the ongoing randomised sham-control trial will address the concern regarding the possible placebo effect, and hopefully further support our encouraging observations.

Evaluation of chronic ischemic heart disease with myocardial perfusion and regional contraction analysis by contrast-enhanced 256-MSCT

To investigate myocardial viability in chronic ischemic heart disease by myocardial perfusion and regional contraction analysis using 256-slice MSCT coronary angiography (CCTA). In 30 patients with prior myocardial infarction (MI), CCTA with retrospective ECG-gating and stress-redistribution thallium-201 SPECT were performed. Using the same raw data as used for CCTA, myocardial perfusion imaging (CT-MPI) was reconstructed at four phases during the cardiac cycle. Mean myocardial attenuation and wall thickness at end-systole and end-diastole were measured in the MI areas depicted by SPECT, and they were compared between viable and non-viable segments categorized by SPECT. End-systolic thickness was significantly greater for viable than for non-viable segments (12.0 ± 3.2 vs. 9.6 ± 3.5 mm, p = 0.0017). There was no difference in end-diastolic thickness. Myocardial attenuation was significantly higher for viable than for non-viable segments in the subendocardium (62 ± 13 vs. 70 ± 11 HU, p = 0.003) and the epicardium (65 ± 13 vs. 80 ± 15 HU, p = 0.0002). The systolic wall thinning and epicardial low-attenuation areas were the indicative findings of CT-MPI for non-viable segments in the prior MI.

ECG-gated Cardiac Magnetic Resonance Imaging for Myocardium and the Results of Echocardiography and Thallium SPECT Scan

Objective This study was to investigate the usefulness and limitations of cardiac magnetic resonance imaging (MRI). We compared echocardiography (ECHO) and perfusion scans to evaluate: left ventricular wall scar formation of the myocardium; hypokinesis, akinesis, or dyskinesis of the myocardium; regurgitation of the aortic and mitral valves; post acute myocardial infarction (AMI) ventricular function; and the viable myocardium (ischemia/infarction). Methods Twenty patients received both cardiac MRI and ECHO. Among them, nine patients received perfusion scans. The modalities and methods examined in this study were not the most advanced or updated protocols. Results We compared the results of cardiac MRI with those of ECHO and perfusion scans. We found significant correlations between the interpretations of left ventricular wall morphological change with dynamic images for hypokinesia, akinesia, and dyskinesia of the myocardium. We also found possible correlations between cardiac MRI and perfusion scans regarding their results to produce a “bull's eye target figure” to evaluate severe ischemia and infarctions. Conclusion We found that cardiac MRI provided a useful adjunct to ECHO on interpretations of left ventricular wall morphological change. The correlations between qualitative interpretations of cardiac MRI versus perfusion scan respective to ‘bull's eye target figures’, were found to be moderately matching. There was an unsatisfactory mismatching of correlations between quantitative by manual input and the drawing inaccuracy and an unavoidable error of the post-processing technique of cardiac MRI on ejection fraction (EF) and end systolic volume (ESV).

Comparison of cardiac MR and 201 Thallium spect in evaluation of myocardial perfusion and viability in coronary artery disease

To compare 201Tl (201-Thallium) single photon emission CT (SPECT) and cardiac MRI (cMRI) for identifying regions of reversible myocardial dysfunction. We conducted an experimental study to compare both modalities by finding the area under ROC curve and coefficient of variability in 42 cases (714 cardiac segments) after a pilot study on 16 cases. We also compared the two modalities by an ingenious method validated in pilot study with common physiological variable, regional wall motion abnormality vs viability assessed independently by both the modalities. The correlation coefficient in the detection of perfusion defects by both the diagnosing modalities was 0.89 and diagnostic region of operating characteristics was 0.97. The sensitivity was 0.96 by 201Tl-SPECT and 0.98 by cMRI, whereas the specificity 0.84 by 201Tl-SPECT and 0.85 by cMRI. The positive and negative predictive value was 0.95 and 0.85 by 201Tl-SPECT, 0.97 and 0.90 by cMRI, respectively. The accuracy of evaluating the viability was 93.15 and 95.69 by the 201Tl-SPECT and cMRI respectively with a ‘p’ value of <0.0001. The study shows a good sensitivity and correlation of both 201Tl-SPECT and cMRI in diagnosing the extent and number of perfusion defects in the myocardium. cMRI is more accurate than 201Tl-SPECT in not only diagnosing myocardial infarcts but also shows its exact location and extent; this is likely to be of use in patients with equivocal 201Tl-SPECT studies. The results were concordant with the other international studies. This is one of the largest study ever carried on comparison of these two modalities.

Semiquantitative Analysis Using Thallium-201 SPECT for Differential Diagnosis Between Tumor Recurrence and Radiation Necrosis After Gamma Knife Surgery for Malignant Brain Tumors

Semiquantitative analysis of thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was evaluated for the discrimination between recurrent brain tumor and delayed radiation necrosis after gamma knife surgery (GKS) for metastatic brain tumors and high-grade gliomas. The medical records were reviewed of 75 patients, including 48 patients with metastatic brain tumor and 27 patients with high-grade glioma who underwent GKS in our institution, and had suspected tumor recurrence or radiation necrosis on follow-up neuroimaging and deteriorating clinical status after GKS. Analysis of 201Tl SPECT data used the early ratio (ER) and the delayed ratio (DR) calculated as tumor/normal average counts on the early and delayed images, and the retention index (RI) as the ratio of DR to ER. A total of 107 tumors were analyzed with 201Tl SPECT. Nineteen lesions were removed surgically and histological diagnoses established, and the other lesions were evaluated with follow-up clinical and neuroimaging examinations after GKS. The final diagnosis was considered to be recurrent tumor in 65 lesions and radiation necrosis in 42 lesions. Semiquantitative analysis demonstrated significant differences in DR (P=.002) and RI (P<.0001), but not in ER (P=.372), between the tumor recurrence and radiation necrosis groups, and no significant differences between metastatic brain tumors and high-grade gliomas in all indices (P=.926 for ER, P=.263 for DR, and P=.826 for RI). Receiver operating characteristics analysis indicated that RI was the most informative index with the optimum threshold of 0.775, which provided 82.8% sensitivity, 83.7% specificity, and 82.8% accuracy. Semiquantitative analysis of 201Tl SPECT provides useful information for the differentiation between tumor recurrence and radiation necrosis in metastatic brain tumors and high-grade gliomas after GKS, and the RI may be the most valuable index for this purpose.

Usefulness of thallium-201 SPECT for prediction of early progression in low-grade astrocytomas diagnosed by stereotactic biopsy

ObjectiveTo establish the value of thallium-201 single-photon emission computed tomography (201Tl-SPECT) as a predictor of early progression in low-grade astrocytomas (LGAs). MethodsWe studied 57 consecutive patients who underwent 201 Tl-SPECT before stereotactic biopsy (n=33) or surgical resection (n=24). The value of radiologic and histopathological variables (201Tl index and MIB-1 index) in predicting progression free survival (PFS) was examined in each group of patients. ResultsDuring a median follow up of 55 months (range, 11–101), progression of the primary lesion was identified in 46 patients (80.7%). Based on Cox's proportional hazards model, the increased thallium uptake was associated with a short PFS in both biopsy and resection groups, whereas the MIB-1 index was significant only in the resection group. Considering the cut-off value, 201Tl index>1.7 was statistically significant for reduced PFS in the biopsy group; however, MIB-1 index was not directly related to the PFS at any level. For the surgical resection group, both a 201Tl index>1.9 and a MIB-1 index>6% were associated with short PFS. Conclusion201Tl SPECT may play a role in prediction of early tumor progression not only in resected LGAs, but also in biopsy-proven LGAs. Therefore, we suggest that patients with LGAs established from biopsy should be considered as high-risk groups for early progression if the tumor shows a high 201Tl uptake, even if the tumor demonstrates low proliferative activity on histopathologic examination.

Brain SPECT Thallium Using Cadmium Zinc Telluride

A 70-year-old man underwent a thallium-201 brain SPECT in the work-up and characterization of a frontotemporal mass. SPECT images were performed on cadmium zinc telluride system during only 5 minutes and after the injection of only 2 mCi. Images demonstrated high thallium uptake in frontotemporal areas considered as a potential malignant tumor. Surgical removal confirmed the diagnosis of malignant glioblastoma. The thallium SPECT fast acquisition imaging on cadmium zinc telluride systems is feasible with reduced injected dose. This method allows a significantly decrease of patient radiation exposure without compromising the image quality. This initial experience needs to be confirmed and optimized in larger clinical studies.

201Thalium SPECT in the detection of recurrent laryngeal carcinoma

Objective To evaluate the diagnostic yield of 201Thallium SPECT in the detection of local and/or regional lymph node dissemination of pharyngo-laryngeal carcinoma. Material and methods 29 Patients who had been diagnosed with pharyngo-laryngeal carcinoma were studied (mean age: 60.9 years). These patients had been treated by surgery, chemotherapy and radiotherapy. At between 3 and 6 months after finishing the treatment, all of them underwent a planar and SPECT study at 1 h after the administration of 148 MBq of 201Thallium. Uptake was scored on four grades: from 0 (no uptake) to 3 (very intense uptake). The presence or non-presence of lymph nodes with uptake was also evaluated. All the results on the scintigraphy were correlated with long term clinical and radiological follow-up (mean: 2.5 years). The studies were classified as positive for recurrence when the uptake was 2–3 and/or with presence of lymph nodes with uptake. Results We obtained 9 true positive, 14 true negative, 3 false positive and 3 false negative results. Sensitivity was 75%, specificity was 82.4%, positive predictive value was 75% and negative predictive value was 82.4%. Two out of three false positives corresponded to the surgical bed uptake and one was attributed to the laterocervical lymph nodes. The three false negatives had grade 1 uptakes, two of them corresponding to pulmonary metastasis without evidence of local recurrence. Conclusions The use of 201Thallium SPECT in the prognostic evaluation in patients with a treated laryngeal carcinoma shows very acceptable results in the detection of local recurrence and/or regional lymph node dissemination.

El SPECT con 201Talio en la detección de recidiva del carcinoma de laringe

Objective To evaluate the diagnostic yield of 201Thallium SPECT in the detection of local and/or regional lymph node dissemination of pharyngolaryngeal carcinoma. Material and methods 29 patients who had been diagnosed with pharyngolaryngeal carcinoma were studied (mean age: 60.9 years). These patients had been treated by surgery, chemotherapy and radiotherapy. At between 3 to 6 month after finishing the treatment, all of them underwent a planar and SPECT study at one hour after the administration of 148 MBq of 201Thallium. Uptake was scored on four grades: from 0 (no uptake) to 3 (very intense uptake). The presence or non-presence of lymph nodes with uptake was also evaluated. All the results on the scintigraphy were correlated with long term clinical and radiological follow-up (mean: 2.5 years). The studies were classified as positive for recurrence when the uptake was 2-3 and/or with presence of lymph nodes with uptake. Results We obtained 9 true positive, 14 true negative, 3 false positive and 3 false negative results. Sensitivity was 75%, specificity was 82.4%, positive predictive value was 75% and negative predictive value was 82.4%. Two out of three false positives corresponded to the surgical bed uptake and one was attributed to the laterocervical lymph nodes. The three false negatives had grade 1 uptakes, two of them corresponding to pulmonary metastasis without evidence of local recurrence. Conclusions The use of 201Thallium SPECT in the prognostic evaluation in patients with a treated laryngeal carcinoma shows very acceptable results in the detection of local recurrence and/or regional lymph node dissemination.