Usefulness of 123I-BMIPP and 201TlCl nuclide scintigraphy in evaluation of myocarditis in patients with polymyositis or dermatomyositis.

ABSTRACT: To investigate the usefulness of 123I-BMIPP/201TlCl scintigraphy for evaluating the presence of myocarditis in patients with polymyositis (PM) or dermatomyositis (DM).We performed a retrospective study of 26 patients diagnosed with new-onset active PM/DM who underwent 123I-BMIPP/201TlCl scintigraphy between 01 April 2010 and 20 March 2015. We determined the 123I-BMIPP/201TlCl ratio and grouped the patients according to presence or absence of a mismatch. We evaluated the relationship between mismatch and the laboratory and echocardiographic findings.Mismatch was found in 13 (50%) patients. There was no statistically significant difference in age, cardiac troponin T, myoglobin, myosin light chain, aldolase levels, E wave/A wave ratio, right ventricular systolic pressure between the mismatch and non-mismatch groups. Left ventricular end-diastolic and end-systolic dimensions were significantly greater in the mismatch group (45.0 vs 42.5 mm, P =  < .01 and 29.5 mm vs 25.0 mm, P < .01). Left ventricular ejection fraction was significantly lower in the mismatch group (63.5% vs 71.5%, P = .04). Significant inverse correlation (r = -0.44, P = .03) was observed between left ventricular ejection fraction and mismatch ratio.The use of 123I-BMIPP/ 201TlCl scintigraphy may be considered for evaluating myocarditis in patients with PM/DM.

Thallium-201 Imaging in Intact Olfactory Sensory Neurons with Reduced Pre-Synaptic Inhibition In Vivo.

In this study, we determined whether the 201Tl (thallium-201)-based olfactory imaging is affected if olfactory sensory neurons received reduced pre-synaptic inhibition signals from dopaminergic interneurons in the olfactory bulb in vivo. The thallium-201 migration rate to the olfactory bulb and the number of action potentials of olfactory sensory neurons were assessed 3 h following left side nasal administration of rotenone, a mitochondrial respiratory chain complex I inhibitor that decreases the number of dopaminergic interneurons without damaging the olfactory sensory neurons in the olfactory bulb, in mice (6-7 animals per group). The migration rate of thallium-201 to the olfactory bulb was significantly increased following intranasal administration of thallium-201 and rotenone (10 µg rotenone, p = 0.0012; 20 µg rotenone, p = 0.0012), compared with that in control mice. The number of action potentials was significantly reduced in the olfactory sensory neurons in the rotenone treated side of 20 µg rotenone-treated mice, compared with that in control mice (p = 0.0029). The migration rate of thallium-201 to the olfactory bulb assessed with SPECT-CT was significantly increased in rats 24 h after the left intranasal administration of thallium-201 and 100 µg rotenone, compared with that in control rats (p = 0.008, 5 rats per group). Our results suggest that thallium-201 migration to the olfactory bulb is increased in intact olfactory sensory neurons with reduced pre-synaptic inhibition from dopaminergic interneurons in olfactory bulb glomeruli.

Postconditioning Accelerates Myocardial Inflammatory Resolution Demonstrated by 14C-Methionine Imaging and Attenuates Ventricular Remodeling After Ischemia and Reperfusion.

BACKGROUND: Methionine uptake after myocardial infarction has been proven to reflect myocardial inflammation. The effect of postconditioning on the post-infarction inflammatory process, however, remains to be elucidated.Methods and Results:In control (n=22) and postconditioning rats (n=23), the left coronary artery was occluded for 30 min, followed by reperfusion for 1, 3, 7, and 14 days. Postconditioning was performed immediately following the reperfusion. 14C-methinine (0.74 MBq) and 201Tl (14.8 MBq) were injected 20 and 10 min prior to sacrifice, respectively. One minute before sacrifice, 150-180 MBq of 99 mTc-MIBI was injected immediately following the re-occlusion of the left coronary artery to verify the area at risk, and left ventricular triple-tracer autoradiography was performed. To examine the ventricular remodeling, echocardiography was performed 2 months after reperfusion in both groups (n=6 each). In the control rats, the methionine uptake ratios on days 1, 3, 7, and 14 were 0.74±0.12, 1.85±0.16, 1.48±0.10, 1.25±0.04, respectively. With postconditioning, methionine uptake was similar on day 3 (1.90±0.21), but was lower on day 7 (1.23±0.22, P<0.05) and day 14 (1.08±0.09, P<0.005). Echocardiography revealed that postconditioning reduced the ventricular end-diastolic (0.97±0.16 to 0.78±0.12 cm, P<0.05) and systolic (0.85±0.21 to 0.55±0.23 cm, P<0.05) dimensions and improved ventricular percentage fractional shortening (12±6.2 to 29±12 %, P=0.01). CONCLUSIONS: 14C-methinine imaging revealed that postconditioning accelerated resolution of inflammation and attenuated ventricular remodeling.

The prognostic value of ultra low-dose thallium myocardial perfusion protocol using CZT SPECT.

The purpose of this study was to assess the prognostic value of ultra-low dose thallium myocardial perfusion imaging. Three hundred and sixty-six patients (245 men) underwent ultra-low dose stress-redistribution imaging on CZT SPECT camera GE Discovery NM 530c. The stress test was performed by bicycle ergometry or regadenoson injection. The activity of 0.5 MBq (0.014 mCi) Tl-201 chloride per kilogram of body weight was administered. The stress images were acquired immediately and redistribution images were taken after 3 h. Patient follow-up was focused on combined end-point (death, myocardial infarction, unstable angina, revascularization and hospitalization for heart failure). Data analysis was performed from hospital database, with a mean period 23 months. Patients with revascularization within 1 month after SPECT was excluded as revascularization for diagnosis. Ischaemia on SPECT was found in 72 patients, 294 patients were without ischaemia. In patients with ischaemia there were 21 (29.2%) subjects with cardiac events, and 23 (7.9%) in patients without ischaemia (HR 4.15, 95% CI 2.30-7.51, p < 0.0001). Ultra-low dose thallium perfusion imaging using CZT camera provides very good prognostic results in assessment of myocardial ischaemia.

Evaluation of Need for Implantable Cardioverter-Defibrillator by Thallium-201 Scintigraphy Among Japanese Patients With Prior Myocardial Infarction.

BACKGROUND: Identifying who among current Japanese patients with prior myocardial infarction (MI) would benefit from an implantable cardioverter-defibrillator (ICD) is imperative. Accordingly, this study seeks to determine whether single-photon emission computed tomography (SPECT) can help identify such patients. Methods and Results: This retrospective study enrolled 60 consecutive patients with prior MI who underwent stress thallium-201 SPECT and ICD implantation from February 2000 to October 2014. Occurrence of arrhythmic death and/or or appropriate ICD therapy, defined as shock or antitachycardia pacing for ventricular fibrillation or tachycardia, was identified until November 2016. During the median follow-up interval of 6.6 years, 18 (30%) patients experienced arrhythmic death and/or appropriate ICD therapy. Multivariate Cox proportional hazard regression analysis revealed that the summed stress score (SSS) [hazard ratio (HR)=1.14; P=0.005] and left ventricular ejection fraction (LVEF) at rest (HR=0.92; P=0.038) were significantly associated with the occurrence of arrhythmic events. Patients with SSS ≥21 and LVEF ≤30%, which were determined to be the best cutoff points, had significantly higher incidence of the arrhythmic events than the other patients (64% vs. 11%; HR=7.18; log-rank P=0.001). CONCLUSIONS: SSS using stress thallium-201 SPECT in combination with LVEF can help determine the need for ICD therapy among current Japanese patients with prior MI.

Diagnostic Performance of the Simultaneous Acquisition Rest 99 mTc-Tetrofosmin/Stress 201Tl Dual-Isotope Protocol With a Semiconductor Camera　- Comparison With the Rest-Stress 99 mTc-Tetrofosmin Protocol.

BACKGROUND: This study compared the diagnostic value of myocardial perfusion imaging (MPI) between the rest-stress 99 mTc-tetrofosmin protocol (Tc/Tc protocol) and simultaneous acquisition rest 99 mTc-tetrofosmin/stress 201Tl dual-isotope protocol (SDI protocol) with a semiconductor camera.Methods and Results: We retrospectively studied 147 patients who underwent stress MPI using a cadmium-zinc-telluride camera and invasive coronary angiography within a 3-month interval. The Tc/Tc and SDI protocols were used in 59 and 88 patients, respectively. The sensitivity, specificity, and accuracy of the summed difference score in per-patient analysis were 56%, 85%, and 69%, respectively, for the Tc/Tc protocol and 89%, 82%, and 85%, respectively, for the SDI protocol. The area under the receiver operating characteristic curve was significantly better for the SDI than Tc/Tc protocol for the left anterior descending artery (0.836 vs. 0.674; P=0.0380), the left circumflex artery (0.754 vs. 0.599; P=0.0441), and in per-patient analysis (0.875 vs. 0.707; P=0.0135). There was no significant difference in the diagnostic accuracy of the summed stress score for any vessel or in per-patient analysis between the 2 protocols. CONCLUSIONS: The SDI protocol had a higher diagnostic accuracy for the detection of coronary ischemia than the Tc/Tc protocol.

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

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.

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 2 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.

Mechanical dyssynchrony and diastolic dysfunction are common in LVH: a pilot correlation study using Doppler echocardiography and CZT gated-SPECT MPI.

Hypertrophic cardiomyopathy (HCM) is an often under-diagnosed cause of left ventricular hypertrophy (LVH). It affects 1/500 of the population, is the most commonly inherited cardiovascular disorder, and can present in apical, concentric, or septal forms. Although most patients are asymptomatic, sudden cardiac death can be the initial presentation of HCM. By retrospectively enrolling patients suspected of having three different types of HCM in the absence of epicardial coronary stenosis, we aimed to examine systolic and diastolic dysfunction and perfusion abnormalities using both Doppler echocardiography and state-of-the-art gated single-photon emission computerized tomography (SPECT) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera and thallium-201. Both regional perfusion and gated SPECT parameters were collected in addition to diastolic parameters from Doppler echocardiography. The results showed that mild ischemia was common in patients suspected of having HCM, with a mean summed stress score of 4.7 ± 4.9 (score 0-4 in 17-segment model). The patients with HCM were associated with discernible left ventricular mechanical dyssynchrony, especially those with the apical form. In addition, diastolic dysfunction was prevalent and early to late ventricular filling velocity ratios were significantly different between groups. By combining gated-MPI and Doppler data, the trivial functional changes in HCM may be identified.

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.

Optimal thallium-201 dose in cadmium-zinc-telluride SPECT myocardial perfusion imaging.

BACKGROUND: We aimed to determine the optimal thallium 201 chloride (thallium-201) dose using a novel ultrafast cardiac gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors (D-SPECT). METHODS AND RESULTS: The optimal thallium-201 dose for obtaining left ventricular (LV) myocardial counts was determined from a phantom study. Consecutive 292 patients underwent stress myocardial perfusion imaging with a thallium-201 injection. Stress test comprised exercise or pharmacological (adenosine) provocation. We calculated an optimal thallium-201 dose that resulted in better LV myocardial counts during 6 minutes of acquisition time. We corrected the respective values according to the patient's age, sex, body mass index (BMI), and type of stress test. The lowest thallium-201 dose for obtaining acceptable imaging was 1.2 million counts. Radiopharmaceutical doses showed a positive correlation with the patient's age (P < .001), sex (P = .012), BMI (P < .001), and type of stress test (P < .001). Multivariate analysis revealed that the patient's BMI and the type of stress test were statistically significant factors for determining the correct radiopharmaceutical dose (P < .001 for both). CONCLUSIONS: For clinical use of the CZT SPECT system, the optimal individual thallium-201 doses can be determined based on the patient's BMI and type of stress test.

Coronary-to-pulmonary artery fistula in adults: Evaluation with thallium-201 myocardial perfusion SPECT.

OBJECTIVES: With the increasing use of multi-detector CT, the number of detected cases with coronary-to-pulmonary artery fistula (CPAF) has increased. Several previous studies reported severe cases of angina, but no appropriate tests to evaluate myocardial perfusion for patients with CPAF have been established. We evaluated the hemodynamic characteristics of CPAF using thallium-201 (Tl-201) single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Tl-201 SPECT was performed in 17 patients with CPAF, but without evidence of coronary artery disease on coronary computed tomography angiography (CCTA) (age, 58.5±13.3 years; 8 men). Quantitative analysis of scintigraphic data was performed. Additionally, perfusion abnormalities were compared with CCTA findings. Medical records were obtained to define clinical data, diagnostic findings, symptoms, management, follow-up data, and major adverse cardiac events (MACE). RESULTS: Six patients (35.2%) showed perfusion abnormalities on SPECT studies and could be classified as follows: 3 patients, no reversible ischemia (3/17, 17.6%); 1 patient, mild ischemia (1/17, 5.8%); and 2 patients, moderate ischemia (2/17, 11.7%). During the follow-up, ten patients (58.8%) improved under medical management and 5 patients (29.4%) underwent surgical ligation for CPAF with symptomatic improvement in 4 patients. Seven patients performed follow-up myocardial perfusion SPECT, and symptomatic improvement correlated well with scintigraphic perfusion improvement in 6 patients No MACE was observed. CLINICAL SIGNIFICANCE: Tl-201 myocardial perfusion SPECT might be useful for determining the hemodynamic status and for risk stratification in patients with CPAF.

Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

Prognostic value of olfactory nerve damage measured with thallium-based olfactory imaging in patients with idiopathic olfactory dysfunction.

Idiopathic olfactory disorder is resistant to treatment, and the recovery time is long. This study investigated the prognostic value of the migration of nasally administered thallium-201 to the olfactory bulb (thallium migration to the OB), a measure of olfactory nerve damage, in patients with idiopathic olfactory disorders. Twenty-four patients with idiopathic olfactory disorders were enrolled in the study (7 women and 17 men; aged 23-73 years). We retrospectively analyzed potential prognostic markers in subjects who underwent thallium-based olfactory imaging with the nasal administration of thallium-201 before conventional treatment with the Japanese herbal medicine tokishakuyakusan and compared those data with the prognosis. Log-rank tests were performed to assess the relationship between thallium migration to the OB (<4.6% [low] vs. ≥4.6% [high]; data dichotomized at the optimal cutoff value) and the duration until recovery of the odor recognition threshold determined by a standard olfactory function test (T&T olfactometry) after the treatment. Upon statistical analysis, we found that high thallium migration to the OB was significantly correlated with better prognosis in patients. Our results suggest that patients with intact olfactory nerve fibers could be selected using thallium-based imaging for the long-term follow-up of olfactory dysfunction.

Incorporation of no-carrier added 200,203Pb and 200,201,202Tl in calcium alginate and hesperidin incorporated calcium alginate beads.

When radioisotopes are injected to human body, instantly free radicals are generated due to the interaction of ionizing radiation with water and fluids present in the body. The vehicle carrying radionuclides into human body should therefore be designed in a way which could also eliminate or reduce such possibilities. For the first time we have used free radical scavenger hesperidin, a polyphenolic compound having a benzo-γ-pyrone with a benzene ring moiety for extraction of no-carrier added (NCA) 200,203Pb and 200,201,202Tl. We have modified CA beads by incorporation of a polyphenol (hesperidin) (CA-Hes). This tailor made beads were characterized and tested for their efficacy towards extraction of no-carrier-added lead and thallium radioisotopes from 40MeV α particle irradiated Hg2Cl2 target.

A case of infected schwannoma mimicking malignant tumor.

BACKGROUND: Infected schwannoma has been reported, this being one of the four cases published in the literature. Infected schwannoma has proven to be a tough diagnostic challenge to the treating tumor surgeon, mimicking infectious entities and most essentially, a malignant tumor. CASE PRESENTATION: The authors report the case of a 64-year-old male with a soft tissue mass in his right gluteal area that presented initially with right leg pain, then later with signs of inflammation on the tumor area. Magnetic resonance imaging (MRI), computed tomography (CT), and thallium-201 scintigraphy studies confirm the presence of soft tissue mass which had continuity with sciatic nerve, with subsequent serial MRI findings suggesting tumor enlargement with cystic degeneration. Increased level of C-reactive protein (CRP) was observed before surgery. During an open biopsy upon tissue sampling, exudates with necrotic tissue were seen. Increased level of CRP and necrotic change suggested the possibility of malignant tumor. Histopathological diagnosis was schwannoma, and group B Streptococcus was detected by culture. After the confirmation of infected schwannoma, enucleation of the tumor was performed. CONCLUSIONS: The report concludes that establishment of a benign pathology is essential when presented with similar clinical findings prior to definitive enucleation of an infected schwannoma.

Evaluation of simultaneous 201Tl/99mTc dual-isotope cardiac SPECT imaging with model-based crosstalk compensation using canine studies.

BACKGROUND: Simultaneous (201)Tl/(99m)Tc-sestamibi dual-isotope myocardial perfusion SPECT imaging can reduce imaging time and produce perfectly registered rest/stress images. However, crosstalk from (99m)Tc into (201)Tl images can significantly reduce (201)Tl image quality. We have developed a model-based compensation (MBC) method to compensate for this crosstalk. The method has previously been validated with phantom and simulation studies. In this study, we evaluated the MBC method using a canine model. METHODS: Left anterior descending or left circumflex coronary artery stenoses were created in 50 adult mongrel dogs weighing 20-30 kg. The dogs were injected with 111 MBq (3 mCi) of (201)Tl at rest, and a SPECT study acquired. Stress was induced by administering adenosine to the dog, followed by injection of 740 MBq (20 mCi) of (99m)Tc-sestamibi at peak stress. A second SPECT study was performed with data acquired in both (201)Tl and (99m)Tc energy windows to provide simultaneous dual-isotope projection data. The images were reconstructed using the ordered-subsets expectation-maximization reconstruction algorithm with compensation for attenuation, scatter, and detector response. For simultaneously acquired (201)Tl data, we also applied the MBC method to compensate for crosstalk contamination from (99m)Tc. RESULTS: Without compensation, (99m)Tc crosstalk increased the estimated (201)Tl activity concentration in the rest images and reduced defect contrast. After MBC, the (201)Tl images were in good agreement with the registered single-isotope images and ex vivo count data. The ischemic (IS) to non-ischemic (NIS) region (201)Tl activity concentration ratios were computed for single-isotope and dual-isotope studies. The correlation with ex vivo IS-NIS ratios was 0.815 after MBC, compared to the 0.495 from data without compensation. In addition, the regression line for the IS-NIS ratios with MBC was almost parallel to the line of identity with a slope of 0.93, compared to a slope of 0.45 without compensation. CONCLUSIONS: These results demonstrate that model-based crosstalk compensation can provide substantial reduction of crosstalk effects in simultaneously acquired myocardial perfusion SPECT images in living biological systems.

Single-cell resolution mapping of neuronal damage in acute focal cerebral ischemia using thallium autometallography.

Neuronal damage shortly after onset or after brief episodes of cerebral ischemia has remained difficult to assess with clinical and preclinical imaging techniques as well as with microscopical methods. We here show, in rodent models of middle cerebral artery occlusion (MCAO), that neuronal damage in acute focal cerebral ischemia can be mapped with single-cell resolution using thallium autometallography (TlAMG), a histochemical technique for the detection of the K(+)-probe thallium (Tl(+)) in the brain. We intravenously injected rats and mice with thallium diethyldithiocarbamate (TlDDC), a lipophilic chelate complex that releases Tl(+) after crossing the blood-brain barrier. We found, within the territories of the affected arteries, areas of markedly reduced neuronal Tl(+) uptake in all animals at all time points studied ranging from 15 minutes to 24 hours after MCAO. In large lesions at early time points, areas with neuronal and astrocytic Tl(+) uptake below thresholds of detection were surrounded by putative penumbral zones with preserved but diminished Tl(+) uptake. At 24 hours, the areas of reduced Tl(+)uptake matched with areas delineated by established markers of neuronal damage. The results suggest the use of (201)TlDDC for preclinical and clinical single-photon emission computed tomography (SPECT) imaging of hyperacute alterations in brain K(+) metabolism and prediction of tissue viability in cerebral ischemia.

Assessment of olfactory nerve by SPECT-MRI image with nasal thallium-201 administration in patients with olfactory impairments in comparison to healthy volunteers.

PURPOSE: The aim of this study was to assess whether migration of thallium-201 ((201)Tl) to the olfactory bulb were reduced in patients with olfactory impairments in comparison to healthy volunteers after nasal administration of (201)Tl. PROCEDURES: 10 healthy volunteers and 21 patients enrolled in the study (19 males and 12 females; 26-71 years old). The causes of olfactory dysfunction in the patients were head trauma (n = 7), upper respiratory tract infection (n = 7), and chronic rhinosinusitis (n = 7). (201)TlCl was administered unilaterally to the olfactory cleft, and SPECT-CT was conducted 24 h later. Separate MRI images were merged with the SPECT images. (201)Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry. RESULTS: Nasal (201)Tl migration to the olfactory bulb was significantly lower in the olfactory-impaired patients than in healthy volunteers. The migration of (201)Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included. CONCLUSIONS: Assessment of the (201)Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.

Low-dose thallium-201 protocol with a cadmium-zinc-telluride cardiac camera.

OBJECTIVES: Thallium-201 is efficient for myocardial perfusion imaging, but leads to relatively high radiation exposure in patients. The purpose of this study was to compare the efficiency of low-dose thallium-201 imaging with cadmium-zinc-telluride (CZT) cameras with regular-dose thallium-201 imaging with conventional cameras. METHODS: We prospectively studied 137 consecutive patients referred for stress myocardial perfusion imaging who had previously had a myocardial single-photon emission computed tomography with thallium-201. We injected at stress a low dose of thallium-201 (1.1 MBq/kg, 28 µCi/kg), performed a 5-7 min scan with a CZT camera (GE DNM 530c), and assessed redistribution imaging when the initial images were abnormal. We compared the CZT scan with the conventional dual-head tomographic camera scan taken previously with a regular dose of thallium-201. RESULTS: The average delay between both scans was 22 months. The stress dose was 88 ± 16 (2.38 ± 0.43 mCi) versus 125 ± 13 MBq (3.38 ± 0.34 mCi; a 30% reduction). The time for camera acquisition was 6 versus 13 min (a 54% reduction). The myocardial counts were increased two-fold with CZT (mean: 446 Kcounts). The quality of CZT images was better in 69% of the cases. There were 59 artifacts with conventional cameras and 29 artifacts with CZT (P<0.01). The diagnostic agreement was calculated in patients without clinical or angiographic changes between both scans (115 patients) and was high (97%). The effective dose at stress was less than 12 mSv. High myocardial counting allowed for further decrease in the injected activity, leading to an effective dose as low as 8 mSv. CONCLUSION: With reduced activities of thallium-201 and low effective doses, the CZT camera provides reliable, high-quality imaging.

Evaluation of the olfactory nerve transport function by SPECT-MRI fusion image with nasal thallium-201 administration.

PURPOSE: The aim of this study was to visualize the human olfactory transport pathway to the brain by performing imaging after nasal thallium-201 ((201)Tl) administration. PROCEDURES: Healthy volunteers were enrolled in this study after giving informed consent (five males, 35-51 years old). The subjects were nasally administered (201)TlCl into either the olfactory cleft. Twenty-four hours later, uptake of (201)Tl was detected by a single photon emission computed tomography (SPECT)/X-ray computed tomography hybrid system. For each subject, an MRI image was obtained and merged with the SPECT image. RESULTS: The peak of the (201)Tl uptake entered into the olfactory bulb in the anterior skull base through the cribriform lamina 24 h after nasal administration of (201)Tl. No participant had olfactory disturbance after treatment. CONCLUSIONS: Nasal (201)Tl administration was safely used to assess the direct pathway to the brain via the nose in healthy volunteers with normal olfactory threshold.