Predictors of abnormality in thallium myocardial perfusion scans for type 2 diabetes.

Type 2 diabetes mellitus (T2DM) increases coronary artery disease (CAD) risk. In this study, we used T2DM clinical variables to predict abnormality in thallium-201 myocardial perfusion scans (Th-201 scans). These clinical variables were summed stress score (SSS), summed rest score, and summed difference score (SDS), with data obtained from 368 male and 428 female participants with T2DM. Multiple linear regression results were as follows. In male participants, body mass index (BMI) and creatinine (Cr) were associated with SSS (ß = 0.224, p < 0.001; ß = 0.140, p = 0.022, respectively), and only BMI was associated with SDS (ß = 0.174, p = 0.004). In female participants, BMI and high-density lipoprotein cholesterol level were associated with SSS (ß = 0.240, p < 0.001; ß = - 0.120, p = 0.048, respectively), and only BMI was correlated with SDS (ß = 0.123, p = 0.031). Our multivariate logistic regression indicated that in male and female participants, BMI was the only independent indicator of high SSS (SSS ≥ 9). In this study, we demonstrated that male patients have a higher SSS and SDS than female patients do in Th-201 scans for T2DM in a Chinese population. For male and female patients, BMI was the strongest predictor of abnormality in Th-201 scans. Our results can help clinicians identify patients with T2DM at high risk of CAD.

Diagnostic value of ultrasonography and TI-201/Tc-99m dual scintigraphy in differentiating between benign and malignant thyroid nodules.

PURPOSE: To evaluate the performance of ultrasonography (US) and TI-201/Tc-99m dual (Tl/Tc) scintigraphy in differentiating between benign and malignant thyroid nodules. METHODS: Eighty-six patients diagnosed to have a thyroid tumor on postoperative histopathologic examination between June 2009 and February 2017 were included in this retrospective study. A radiologist reviewed the US and Tl/Tc scintigraphy reports along with all available clinical and histopathologic information. On Tl/Tc scintigraphy, a nodule in which uptake was higher in the delayed phase than in the surrounding parenchyma was defined as a delayed accumulation pattern and a nodule in which uptake was higher in the delayed phase than in the early phase was defined as a persistent pattern. The Tl/Tc scintigraphy images were evaluated in a blinded manner to assess reproducibility. A statistical analysis was performed to identify features associated with malignancy. Interobserver variability was calculated using the κ statistic. RESULTS: US had higher sensitivity (81.2%), specificity (88.2%), and positive (96.6%) and negative (53.6%) predictive values than Tl/Tc scintigraphy. An ill-defined margin and microcalcification were independent predictors of a malignant thyroid nodule on multivariate logistic regression (P = 0.003 and P = 0.014, respectively). The persistent pattern had high specificity (85.7%) equivalent to that of US but had lower sensitivity (34.7%). The κ values for the delayed accumulation and persistent patterns were 0.66-0.78 and 0.32-0.50, respectively. CONCLUSIONS: An ill-defined margin and microcalcification on US were independent predictors of a malignant thyroid nodule. A persistent pattern seen on Tl/Tc scintigraphy could contribute to the differential diagnosis.

Targeting of endothelin receptors in the healthy and infarcted rat heart using the PET tracer 18F-FBzBMS.

UNLABELLED: The endothelin subtype-A receptor (ET-A) is a promising therapeutic target in cardiovascular disease. We sought to determine the feasibility of an (18)F-labeled ligand, (18)F-(N-[[29-[[(4,5-dimethyl-3-isoxazolyl)amino]sulfonyl]-4-(2-oxazolyl)[1,19-biphenyl]-2-yl]methyl]-N,4-fluorobenzamide) ((18)F-FBzBMS), for imaging ET-A in the healthy and injured rat heart. METHODS: Male Wistar rats were used for all experiments. The specificity of cardiac (18)F-FBzBMS uptake was determined in healthy animals (n = 23) using pretreatment with various blocking agents and doses. Myocardial infarction (MI) was induced by permanent left coronary ligation in 32 animals. Autoradiography was conducted to determine regional FBzBMS distribution relative to tissue perfusion at various times after MI. Histology and immunohistochemistry were performed for validation. The feasibility of in vivo detection of the tracer signal was tested using dedicated small-animal PET (n = 6). RESULTS: At autoradiography, intravenous pretreatment with the selective ET-A blocker BMS-207940 reduced myocardial FBzBMS uptake by 93% ± 0.7%. Oral pretreatment with the clinical blocker bosentan resulted in a dose-dependent partial blockade (5 mg/kg, 48% ± 6%; 50 mg/kg, 61% ± 7%; and 100 mg/kg, 88% ± 0.7%). After MI, FBzBMS uptake was preserved in the infarct region from day 1 to month 6, whereas the perfusion tracer (201)Tl showed a persistent defect (MI-to-remote ratios: (201)Tl, 0.23 ± 0.28, 0.39 ± 0.07, 0.31 ± 0.07, 0.24 ± 0.12, 0.29 ± 0.10, and 0.23 ± 0.09; and FBzBMS, 0.94 ± 0.28, 0.92 ± 0.20, 0.88 ± 0.13, 0.82 ± 0.12, 0.80 ± 0.11, and 0.84 ± 0.08 at day 1, day 3, week 1, month 1, month 2, and month 6, respectively) (P < 0.01 vs. (201)Tl). Ex vivo analysis confirmed ET-A expression in the infarct area, where the signal was partially colocalized with CD31 expression on endothelial cells. In vivo small-animal PET successfully confirmed specific uptake and blockade of FBzBMS in healthy myocardium. CONCLUSION: Cardiac uptake of the PET tracer (18)F-FBzBMS is specific for ET-A expression in rats, shows infarct-related alterations, and can be imaged noninvasively. Further efforts to establish myocardial ET-A imaging methodology are warranted, with the perspective of determining role, efficacy, and benefit of ET-A targeted drug treatment in cardiovascular disease.

The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glutathione reductase activity.

AIM: The aim of the study was to evaluate the inhibitory effects of thallium-201 ((201)Tl) solution on human erythrocyte glutathione reductase (GR) activity. METHODS: Erythrocyte GR was initially purified by 2',5'-adenosine diphosphate Sepharose-4B affinity and Sephadex G-200 gel filtration chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the (201)Tl solution including Tl(+), Fe(+3) and Cu(+2) metals and the in vitro effects of the radiation effect of the (201)Tl solution and nonradioactive Tl(+), Fe(+3) and Cu(+2) metals on human erythrocyte GR enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at (+)4 °C. RESULTS: Glutathione reductase was purified 2033-fold at a yield of 28.17%. (201)Tl solution and radiation exposure had inhibitory effects on the enzyme activity. Besides, effects of nonradioactive Tl(+), Fe(+3) and Cu(+2) were studied on enzyme activity in vitro. Furthermore, seven human patients were also used for in vivo studies of (201)Tl solution. CONCLUSION: It was detected in in vitro and in vivo studies that the human erythrocyte GR enzyme is inhibited due to the radiation effect of (201)Tl solution.

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.

Nodular fasciitis of the hand in a young athlete. A case report.

Nodular fasciitis is a rapidly growing mass, with high cellularity and mitotic activity, that can be both clinically and histologically misdiagnosed as a soft tissue sarcoma. Nodular fasciitis of the hand is an extremely rare condition. We report a 17-year-old male hand-ball player with nodular fasciitis in the dominant hand. The patient presented with a rapidly growing mass in his right hand and no history of major trauma. On physical examination, a painful mass measuring 2 cm in diameter was observed in the first web space. Magnetic resonance imaging (MRI) demonstrated a subcutaneous mass with isointensity on T1-weighted images and inhomogeneous high intensity on T2-weighted images. The lesion was inhomogeneously enhanced after intravenous administration of gadolinium. Moreover, thallium-201 scintigraphy showed high uptake at the early phase and no wash-out at the delayed phase. We performed an excisional biopsy. The mass was present subcutaneously and adhered to the interosseous muscle fascia. Although a pathological examination by frozen section during surgery showed a low-grade spindle cell sarcoma, the final histological diagnosis was nodular fasciitis. There was no evidence of local recurrence at the recent follow-up 2 years after the operation. We speculate that repeated small injuries as a result of sports activities played an important causative role in the nodular fasciitis.

Stunned myocardium in transient left ventricular apical ballooning: a serial study of dual I-123 BMIPP and Tl-201 SPECT.

BACKGROUND: This study was designed to assess the influence of coronary endothelial function and the serial changes of dual myocardial single photon emission computed tomography (SPECT) imaging in transient left ventricular (LV) apical ballooning. METHODS AND RESULTS: We evaluated 35 consecutive patients (8 men and 27 women; mean age, 71 +/- 13 years) with transient LV apical ballooning. All patients underwent coronary angiography with acetylcholine provocation 1 month after onset. Iodine 123 beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) and thallium 201 dual myocardial SPECT was serially performed on day 1 of admission and 1 month and 6 months later. In 8 of 35 patients (23%), epicardial coronary spasm was induced by acetylcholine infusion. At the peak acetylcholine dose (100 microg), diffuse coronary vasoconstriction developed in 19 of 35 patients (54%). Of 19 patients, 13 had diffuse coronary vasoconstriction with chest pain and ST-segment depression. The total defect score of I-123 BMIPP and Tl-201 SPECT showed marked perfusion-fatty acid metabolic mismatches (13.7 +/- 3.6 vs 8.7 +/- 2.3, P < .001) at the LV apex during the acute phase but few mismatched areas (2.1 +/- 1.1 vs 1.5 +/- 1.4, P = not significant) at 6 months. CONCLUSIONS: Transient LV apical ballooning might be caused by stress-induced coronary epicardial spasm or endothelial dysfunction, resulting in myocardial stunning.

Does supplementation of contrast MR imaging with thallium-201 brain SPECT improve differentiation between benign and malignant ring-like contrast-enhanced cerebral lesions?

OBJECTIVE: To determine whether thallium-201 ((201)Tl) brain single photon emission computed tomography (SPECT) could supplement magnetic resonance (MR) imaging diagnostic information by visual comparison of two separate data sets from patients with ring-like contrast-enhanced cerebral lesions. METHODS: A combination of MR imaging and (201)Tl brain SPECT sets obtained from 13 patients (10 men, 3 women) ranging in age from 26 years to 86 years (mean 61.0 years) were retrospectively reviewed. A total of 12 patients had a solitary lesion, and the others had multiple lesions. All but two intracranial foci were pathologically confirmed. The final diagnoses were six glioblastomas, two cerebral metastases from lung cancer, and one each of abscess, resolving hematoma, primary central nervous system lymphoma, toxoplasmosis, and radiation necrosis. The two separate image formats (MR images and SPECT) were shown to ten readers with practical experience. All of the MR images for each patient were shown to each reader first. After interpreting them, the readers were shown the SPECT images. Images were scored in terms of how benign or malignant the foci were on a 5-point scale from "definitely benign" to "definitely malignant." RESULTS: The improvement in the performance of all ten readers was from 67.7% to 93.8% in mean accuracy (P = 0.0028) and from 0.730 to 0.971 in mean Az value (P = 0.0069) after they were shown the (201)Tl brain SPECT images. CONCLUSIONS: (201)Tl brain SPECT should substantially increase confidence in the diagnosis of intracranial lesions with ring-like contrast enhancement when MR imaging does not permit differentiation between benign and malignant disease.

Myocardial kinetics of (201)Thallium, (99m)Tc-tetrofosmin, and (99m)Tc-sestamibi in an acute ischemia-reperfusion model using isolated rat heart.

OBJECTIVE: (201)Thallium (TL), (99m)Tc-tetrofosmin (TF), and (99m)Tc-sestamibi (MIBI) are extensively used as myocardial perfusion agents. The objective of the present study was to evaluate their kinetics under acute ischemia-reperfusion. METHODS: Isolated rat hearts, perfused by the Langendorff method at a constant flow rate of 10 ml/min, were allotted to normal control, mild ischemia, and severe ischemia groups, in which 20-min tracer wash-in was conducted followed by a 25-min tracer washout. No-flow ischemia (15 min for mild ischemia groups; 30 min for severe ischemia groups) was induced before conducting wash-in and washout in the ischemia groups. Whole-heart radioactivity was determined with an external gamma detector. Myocardial flow rate (K (1), ml/min) and clearance rate (k (2), min(-1)) were calculated. RESULTS: K (1TL), K (1TF), and K (1MIBI) decreased according to the severity of ischemia (K (1TL) 5.32 +/- 0.53, 4.76 +/- 0.70, and 1.44 +/- 0.59; K (1TF) 3.80 +/- 0.70, 2.73 +/- 0.99, and 1.09 +/- 0.45; and K (1MIBI) 3.45 +/- 1.10, 2.15 +/- 0.82, and 1.05 +/- 0.13, in the normal control, mild, and severe ischemia groups, respectively). K (1) was significantly higher for TL than for the (99m)Tc tracers (P < 0.05), but the (99m)Tc tracers had equivalent K (1) values. k (2TL) increased significantly (P < 0.05) in the ischemia groups (k (2TL) 0.062 +/- 0.013, 0.11 +/- 0.045, and 0.12 +/- 0.035), but showed no significant difference between the ischemia groups. k (2MIBI) and k (2TF) were significantly (P < 0.05) lower than k (2TL) and increased significantly (P < 0.05) in the severe ischemia group (k (2TF) 0.0056 +/- 0.0022, 0.0037 +/- 0.0015, and 0.024 +/- 0.015; and k (2MIBI) 0.00072 +/- 0.0011, 0.00038 +/- 0.00076, and 0.042 +/- 0.034). k (2MIBI) was significantly (P < 0.05) lower than k (2TF) in the normal control and mild ischemia groups. CONCLUSIONS: Tracer extraction was higher for TL than for the (99m)Tc tracers and all tracers decreased according to the severity of ischemia-reperfusion in the three tracer groups. The clearance kinetics of not only MIBI but also TF is possibly useful for the evaluation of the severity of ischemia, and the Langendorff method and a methodological approach by continuous determinations of radioactivity may serve for the quantitative analysis of tracer kinetic profiles.

The use of perfusion scintigraphy to differentiate proximal right coronary artery stenosis from distal right coronary artery stenosis in patients with inferior left ventricular ischaemia.

OBJECTIVE: The identification of patients with a significant proximal right coronary artery (RCA) is of clinical relevance since it may direct diagnostic and therapeutic strategies. This study was performed to determine parameters of (201)Tl RV perfusion SPECT which can be used to discriminate between proximal and distal RCA stenosis in patients with inferior left ventricular (LV) ischaemia. In addition, feasibility and reproducibility of a new semi-quantitative method for the assessment of RV perfusion were evaluated. METHODS: Inferior LV ischaemia was due to a single distal RCA stenosis in 10 (group I) and proximal RCA stenosis in 27 patients (group II). Twenty patients with normal (201)Tl myocardial perfusion scintigraphy and low likelihood of cardiovascular disease were used as a reference (group III). RESULTS: RV (201)Tl stress uptake did not differ between the three groups. However, group II showed a significantly higher (201)Tl rest uptake indicating RV redistribution whereas in group I and III tracer washout was shown. Extent and severity of LV inferior ischaemia was not different between groups I and II. RV redistribution has a sensitivity of 0.74, a specificity of 0.80, and an overall agreement of 0.76 for detecting proximal RCA stenosis. The feasibility of the assessment of RV (201)Tl perfusion was 94%. Inter-observer and intra-observer coefficients of variation for RV (201)Tl perfusion assessment were 1.5 and 2.4%, respectively. CONCLUSION: RV (201)Tl perfusion scintigraphy is feasible and reproducible. RV (201)Tl redistribution can be used to discriminate between proximal and distal RCA stenosis in patients with inferior LV ischaemia.

Prognostic significance of increased thallium-201 lung uptake during dipyridamole myocardial scintigraphy: comparison with exercise scintigraphy.

OBJECTIVE: To compare the incidence of cardiac events among patients with increased lung uptake of thallium after dipyridamole stress, matched subjects without such uptake and matched subjects with increased lung uptake during exercise stress. DESIGN: Retrospective case control study based on quantitative and semiquantitative visual consensus analysis of thallium scintigraphy. SETTING: Nuclear cardiology laboratory of a university teaching hospital. PATIENTS: Thirty-six patients with increased lung activity after dipyridamole stress and two groups of matched control subjects identified from 3150 consecutive thallium single photon emission computed tomography studies. INTERVENTIONS: Telephone follow-up and chart reviews to determine the incidence of cardiac events. MAIN RESULTS: Cardiac events were significantly less frequent in the study group with increased lung uptake after dipyridamole stress (two of 36,5%) than in the control group with increased thallium lung uptake at exercise scintigraphy (nine of 36,25%; P = 0.046). CONCLUSIONS: Increased lung uptake of thallium has less ominous short term prognostic significance when observed in association with dipyridamole stress rather than with exercise.