Nasal thallium-201 uptake in patients with parosmia with and without hyposmia after upper respiratory tract infection.

BACKGROUND: In this study, we aimed to determine whether nasal thallium-201 uptake of the olfactory cleft and olfactory bulb (OB) differs between patients with parosmia with and without hyposmia after upper respiratory tract infection (URTI). METHODS: Twenty patients with parosmia after URTI were enrolled in this study (15 women and 5 men, 28 to 76 years old). Nasally administered thallium-201 migration to the OB, nasal thallium-201 uptake ratio in the olfactory cleft, and OB volume were determined in 10 patients with normal T&T olfactometry (Daiichi Yakuhin Sangyo, Tokyo, Japan) odor recognition thresholds (≤2.0) who still complained of parosmia (parosmia group), and 10 patients with T&T odor recognition thresholds >2.0 (parosmia and hyposmia group). RESULTS: The nasal thallium-201 uptake ratio in the olfactory cleft was significantly higher in the parosmia group than in the parosmia and hyposmia group (p = 0.0015). Thallium-201 migration to the OB was not significantly different between the 2 groups (p = 0.31). The OB volume was significantly larger in the parosmia group than that in the parosmia and hyposmia group (p = 0.029); however, the mean OB volume in both the groups was lower than the normal threshold value in healthy individuals. CONCLUSION: Our results signify the recovery of the olfactory epithelium; however, the olfactory neural projections to the OB and regeneration of OB were not complete in patients with parosmia with normal T&T recognition thresholds after URTI.

Thallium stable isotope fractionation in white mustard: Implications for metal transfers and incorporation in plants.

We studied thallium (Tl) isotope fractionation in white mustard grown hydroponically at different Tl doses. Thallium isotope signatures in plants indicated preferential incorporation of the light 203Tl isotope during Tl uptake from the nutrient solution. Negative isotope fractionation was even more pronounced in dependence on how much the available Tl pool decreased. This finding corresponds to the concept of isotope overprinting related to a high contamination level in the growing media (solution or soil). Regarding Tl translocation in plants, we observed a large Tl isotope shift with an enrichment in the heavy 205Tl isotope in the shoots relative to the roots in treatments with low/moderate solution Tl concentrations (0.01/0.05 mg Tl/L), with the corresponding α205/203Tl fractionation factors of ˜1.007 and 1.003, respectively. This finding is probably a consequence of specific (plant) reactions of Tl replacing K in its cycle. The formation of the S-coordinated Tl(I) complexes, potentially affecting both Tl accumulation and Tl isotope fractionation in plants, however, was not proven in our plants, since we did not have indication for that on the basis of X-ray absorption spectroscopy, suggesting that Tl was mainly present as free/hydrated Tl+ ion or chemically bound to O-containing functional groups.

Effects of atrial fibrillation on myocardial washout rate of thallium-201 on myocardial perfusion single-photon emission computed tomography.

BACKGROUND: Myocardial perfusion single-photon emission computed tomography (SPECT) with thallium (Tl)-201 is an established modality for evaluating myocardial ischemia. We assessed the effects of atrial fibrillation (AF) on the myocardial washout rate (WR) of Tl-201 on myocardial perfusion SPECT. PATIENTS AND METHODS: A total of 231 patients with no evidence of myocardial ischemia were enrolled retrospectively in this study. Patients were divided into two groups on the basis of the ECG at the time of myocardial perfusion SPECT. The mean myocardial WR of Tl-201 was calculated from the stress and the redistribution Bull's eye maps. RESULTS: There were 34 patients with AF and 197 patients with sinus rhythm. There were no significant differences in clinical variables, except for older age and higher heart rate in patients with AF. Myocardial WR of Tl-201 was significantly lower in patients with AF than those with sinus rhythm (46±12 vs. 51±8%, P=0.03). Multivariate analysis including these factors showed that female sex (ß=0.18, P=0.02), AF (ß=-0.14 P=0.03), hemoglobin (ß=-0.18, P<0.01), and serum creatinine (ß=0.24, P<0.01) were determinants of myocardial WR of Tl-201. CONCLUSION: Our data suggest that AF is associated with reduced myocardial WR of Tl-201 on myocardial perfuison SPECT.

Effects of chronic kidney disease on myocardial washout rate of thallium-201 in patients with normal myocardial perfusion on single photon emission computed tomography.

BACKGROUND: Myocardial perfusion single photon emission computed tomography (SPECT) is often performed even in patients with chronic kidney disease (CKD). We assessed the effects of CKD on myocardial washout rate (WR) of thallium (Tl)-201 in patients with normal myocardial perfusion on SPECT. METHODS: Two hundred and fifty-six patients with normal myocardial perfusion were enrolled in this study. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2. Patients with eGFR ≥ 60 ml/min/1.73 m2 were assigned to a control group. The mean myocardial WR of Tl-201 was calculated from the stress and the redistribution Bull's eye maps. RESULTS: With progressive CKD stages, systolic blood pressure and incindence of hypertension were increased. All patients in CKD stage 5 group were being treated with hemodialysis. Myocardial WR of Tl-201 was significantly higher in all of the CKD groups than control group. With progressive CKD stages, myocardial WR of Tl-201 was increased (stage 3, 52.2 ± 9.2%; stage 4, 55.5 ± 8.1%; and stage 5, 58.9 ± 5.6%). Multivariate analysis showed that hemoglobin (ß = -0.24, p < 0.001) and eGFR (ß = -0.24, p = 0.002) were the major determinants of myocardial WR of Tl-201, but hemodialysis was not. CONCLUSIONS: Our data suggest that CKD is associated with increased myocardial WR of Tl-201 in patients with normal perfusion on SPECT.

Validation of prone myocardial perfusion SPECT with a variable-focus collimator versus supine myocardial perfusion SPECT with or without computed tomography-derived attenuation correction.

OBJECTIVE: The purpose of this study is to evaluate whether prone myocardial perfusion single-photon emission computed tomography (MPS) with thallium-201 acquired through a variable-focus collimator (IQ-SPECT) can correct for soft-tissue attenuation. METHODS: Thirty-nine patients underwent thallium-201 stress MPS with IQ-SPECT. Delayed images acquired with the patients in the prone position were compared with delayed images obtained with the patients in the supine position with computed tomography-derived attenuation correction (CTAC) (S-CTAC images) or without CTAC (S-NCTAC images). Quantitative tracer uptake (QTU) and semi-quantitative defect scores were determined for the 17 standard myocardial segments. Segments were categorized into anterior-anteroseptal, lateral, inferior, and apex, and areas with defect decision were determined by using the defect scores. RESULTS: Image quality in the prone images was similar to that of S-NCTAC and S-CTAC images. In male patients, QTU in prone images was equivalent to that in S-CTAC images in the anterior-anteroseptal area, but was significantly lower than that in S-CTAC images in the inferior area. In female patients, QTU in prone images was similar to that in S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. In male and in female patients, QTU in the apex was significantly greater in the prone images than that in the S-CTAC images. In the combined male and female patient group, the defect decision for prone images was similar to that for S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. Apical defects were observed more frequently in S-CTAC images than in prone or S-NCTAC images. CONCLUSIONS: Fewer artificial defects were observed in the apex of images acquired by prone imaging than by S-CTAC imaging. Prone images improved attenuation and had similar defect decision as S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas.

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.

201Tl heart-liver radioactivity uptake ratio and prediction of decompensation in patients with cirrhosis.

PURPOSE: The present study aimed to determine the predictive value of the heart-liver uptake ratio (H/L ratio) of rectally administered (201)Tl scintigraphy for hepatic decompensation, which was conducted in 107 patients with cirrhosis. METHODS: We retrospectively assessed the predictive value of a noninvasive parameter, H/L ratio, for decompensation during a median follow-up period of 45.4 months using follow-up data from 1996 through 2008 for 107 patients with compensated cirrhosis. Logistic regression analysis and odds ratio estimates were used to estimate independent value of the H/L ratio on the risk of decompensation with 95% confidence intervals. RESULTS: At first visit, all subjects were confirmed as patients with compensated cirrhosis, 39 by liver biopsy and 68 by standard laboratory and radiological criteria. At end of the evaluation time, 81 patients remained compensated, whereas 26 patients decompensated as evidenced by ascites in 23, hepatic encephalopathy in 8, and variceal bleeding in 1 patient. First-visit parameters except bilirubin level, alanine aminotransferase (ALT), and H/L ratio and last visit parameters except ALT and aspartate aminotransferase-ALT ratio were significantly different between the 2 groups as ascertained by Wilcoxon rank sum test (P < 0.05). Among those parameters, we found that the last visit H/L ratio was a strongly reliable predictor of decompensation with an odds ratio estimates of 14.443, area under the receiver operating characteristic curve of 0.825, cutoff of 0.4, sensitivity of 73.1 %, and specificity of 71.6%. CONCLUSIONS: This evidence indicates that in patients with compensated cirrhosis, an increased H/L ratio at follow-up may be a useful predictive parameter showing a high risk of progression to a decompensated state.

[Clinical diagnosis of the olfactory nerve transport function].

Nasal administration of macromolecular drugs (peptides, nanoparticles) has a possibility to enable a drug delivery system beyond the blood brain barrier via olfactory nerve transport. Basic research on nasal drug delivery to the brain has been well studied. However, evaluation of the olfactory nerve transport function in patients with olfactory disorders has yet to be done, although such an evaluation is important in selecting candidates for clinical trials. Current olfactory function tests are useful for the analysis of olfactory thresholds in olfaction-impaired patients. However, the usefulness of using the increase in olfactory thresholds in patients as an index for evaluating olfactory nerve damage has not been confirmed because of the difficulty in directly evaluating the viability of the peripheral olfactory nerves. Nasally administered thallium-201 migrates to the olfactory bulb, as has been shown in healthy volunteers. Furthermore, transection of olfactory nerve fibers in mice significantly decreases migration of nasally administered thallium-201 to the olfactory bulb. The migration of thallium-201 to the olfactory bulb is reduced in patients with impaired olfaction due to head trauma, upper respiratory tract infections, and chronic rhinosinusitis, relative to the values in healthy volunteers. Nasally administrating thallium-201 followed by single photon emission computed tomography, X-ray computed tomography and magnetic resonance imaging might be useful in choosing candidates for clinical trials of nasal drug delivery methods to the brain.

The role of metamizol induction for the detection of perfusion reversibility on thallium-201 myocardial perfusion scintigraphy.

OBJECTIVE: Metamizol, probably with its vascular smooth muscle relaxant effect, enhances rest myocardial perfusion with the use of technetium-99m-methoxyisobutylisonitrile. We aimed to investigate whether metamizol induction is also able to increase the detectability of the ischemic/jeopardized myocardium during thallium-201 myocardial perfusion scintigraphy (MPS). METHODS: Twenty patients who had partially reversible/irreversible perfusion defects on their routine stress-redistribution-reinjection thallium-201 MPS were enrolled and metamizol-induced thallium-201 MPS (111 MBq thallium-201 was injected 45 min after 1 g oral metamizol) was acquired (10 min, 1 and 3 h later). Routine MPS and metamizol-induced MPS images were interpreted on the model of 17 segments using a visual uptake score (VUS; 0=normal, 1=mild, 2=moderate, 3=significant decreases, 4=no uptake). Thallium-201 uptake ratios (mean counts in the region of the perfusion defect/mean counts in the region of the normal-perfused wall) were calculated for each MPS. Blood pressure was monitored at 15-min intervals. MPS were compared with coronary angiography results. RESULTS: Visual uptake score and thallium-201 uptake ratio results indicated that in the first and third hour metamizol-induced thallium-201 uptake was significantly higher (P<0.001) than the redistribution/reinjection studies in 26 ischemic myocardial walls. Fourteen myocardial walls showed no thallium-201 uptake on either MPS and were considered as myocardial infarction. Statistically significant but asymptomatic decreases in blood pressure were observed. Coronary angiography results were in concordance with metamizol-induced MPS. CONCLUSION: Metamizol increases the detectability of ischemic/viable myocardium during MPS with thallium-201 and could be used with MPS.

Bio-sorption of Tl-201 radionuclide on olive pomace.

This work presents an investigation on the bio-sorption of Tl-201 radionuclide used in nuclear medicine on olive pomace. The experimental parameters were chosen as temperature, the initial pH of the solution, stirring speed, bio-sorbent dose and nominal particle size of bio-sorbent. The initial pH of the solution was found to be the most effective parameter. Thermodynamic analysis gave negative values for ΔG and ΔH. The kinetics of the bio-sorption process fitted very well to the pseudo-second order rate model.

Tumor grade-related thallium-201 uptake in chondrosarcomas.

OBJECTIVES: Diagnosis of low-grade chondrosarcoma, especially discrimination between enchondroma and low-grade chondrosarcoma, may be difficult pathologically. The aim of this study was to evaluate the value of thallium-201 (Tl-201) scintigraphy in the diagnosis of chondrosarcoma and to investigate whether there was a correlation between Tl-201 uptake and tumor grade. METHODS: We retrospectively evaluated 121 patients with pathologically proven bone and soft tissue tumors diagnosed between the years 1999 and 2007. All patients were followed by the Bone and Soft Tissue Tumor Working Group in our hospital. Twenty-three patients, mean age 44 +/- 15 (range 17-72) years, with a diagnosis of cartilaginous tumors were included. Increased Tl-201 uptake at the lesion sites greater than background was evaluated as malignant tumor. For the pathologic classification, a grading system (grade 1-3) based on the histopathologic findings was used. Pearson correlation coefficient was used to determine whether there was any correlation between Tl-201 uptake and tumor grade in chondrosarcoma. RESULTS: There were 7 enchondromas and 16 chondrosarcomas. Four of 16 patients with chondrosarcoma had lesions pathologically classified as grade 3, 5 as grade 2, and 7 had grade 1 chondrosarcoma. Increased Tl-201 uptake was observed in all patients with grade 3 chondrosarcoma and 2 patients with grade 2 chondrosarcoma. Of 10 patients with chondrosarcoma, 3 grade 2 chondrosarcomas and 7 grade 1 chondrosarcomas, there was no Tl-201 uptake in the tumor region. A significant correlation was found between Tl-201 uptake and tumor grade in chondrosarcoma (p = 0.002, r = 0.71). Only a few reports in literature have demonstrated false negative results in low-grade chondrosarcoma. CONCLUSION: Tl-201 uptake was related to tumor grade in chondrosarcoma. If there is a possibility of chondrosarcoma, Tl-201 scintigraphy should be reported with caution.

Use of thallium transport to visualize functional olfactory nerve regeneration in vivo.

OBJECTIVE: To image olfactory nerve regeneration in vivo using a high-resolution gamma cam- era and radiography after nasal administration of thallium-201 (olfacto-scintigraphy). METHODS: Six Wistar rats were trained to avoid the smell of cycloheximide as a test of olfactory function. The olfactory nerve fibers of 3 rats were then carefully transected bilaterally with a Teflon knife, avoiding damage to the olfactory bulbs. The remaining 3 rats underwent sham operations and were used as controls. Steel wires were implanted in the left olfactory bulb of each rat for locating the bulbs with plain X-rays. The rats were assessed 2, 14, 28, and 42 d after the olfactory nerve transection or sham operation for their ability to detect odours and for transport of 201Tl to the olfactory bulb area 8 h after nasal administration of 201Tl. RESULTS: Both transport of 201Tl to the olfactory bulb area (p < 0.04) and ability to detect odours (p < 0.04) significantly increased with a time course after olfactory nerve transection. CONCLUSION: 201Tl transport to the olfactory bulb may be useful to visually assess olfactory ability in vivo. We plan to test olfacto-scintigraphy clinically by nasal administration of 201Tl in patients with posttraumatic olfactory loss.

Thallium-201 SPECT in brain gliomas: Quantitative assessment in differential diagnosis between tumor recurrence and radionecrosis.

OBJECTIVE: To compare various published thallium-201 uptake indexes in the differential diagnosis in recurrent brain gliomas. MATERIAL AND METHODS: Thallium-201 SPECT studies were performed in 79 patients previously treated for glial tumor with clinical or radiologic suspicion of recurrence. Regions of interest were established in the tumor area and in other sites with normal uptake. RESULTS: A high linear correlation was found among indices, with significant differences between all index pairs. Logistic regression analysis confirmed high colinearity among indexes, with index 3 (mean counts in tumor/mean counts in contralateral hemisphere) showing a slightly superior predictive power to differentiate tumor absence from tumor presence and tumor absence from low-grade recurrence. These findings were supported by analysis of areas under the ROC curve. CONCLUSIONS: The uptake indices studied behave similarly in the evaluation of a possible recurrence of a glial brain lesion and should be considered complementary to visual evaluation as a semi-objective tool.

Comparison of exercise-rest-reinjection Tl-201 imaging and rest sublingual isosorbide dinitrate Tc-99m MIBI imaging for the assessment of myocardial viability.

PURPOSE: Nitrate administration has been proposed to enhance the detection of myocardial viability when performing myocardial perfusion imaging. In this study, we aimed to compare Tl-201 exercise-rest-reinjection protocol with rest isosorbide dinitrate (ISDN)-Tc99m MIBI study in the same population examined for the myocardial viability. METHODS: Twenty-six patients with coronary artery disease who had fixed segmental defects on exercise-rest-Tl-201 imaging were studied. All of them underwent Tl-201 reinjection study. Within 1 week of Tl-201 imaging, rest-Tc99m MIBI imaging was performed after sublingual 5 mg ISDN administration (2-day protocol). For each study, tomograms were divided into 20 segments based on three short-axis slices, one vertical long-axis representing the totality of the left ventricle and regional tracer uptake was quantitatively analyzed. Regional tracer uptake was evaluated in 20 myocardial segments for all patients. Viability was defined as presence of tracer uptake >/=50% of peak activity on each study. A total 520 myocardial segments were assessed by semi quantitative analysis. RESULT: On the baseline rest Tl-201 studies, 211 segments of the 520 segments that were analyzed had <50% of peak activity. Of these segments, 42 (20%) showed reversibility after reinjection Tl-201 imaging and 55 segments (27%) described as viable on the rest ISDN-Tc99m MIBI imaging. There was 89% concordance between the ISDN-Tc99m MIBI study and Tl-201 reinjection study regarding viable myocardial segments. Of the 23 segments with discordant results, 18 were irreversible on Tl-201 reinjection study, but showed >/=50% uptake on ISDN-Tc99m MIBI. CONCLUSION: Observation of good agreement between Tl-201 reinjection and ISDN-Tc99m MIBI study studies led us to suggest the use of ISDN enhanced imaging in the evaluation of myocardial viability.

Technetium-99m pyrophosphate/thallium-201 dual-isotope SPECT imaging predicts reperfusion injury in patients with acute myocardial infarction after reperfusion.

PURPOSE: Microcirculatory failure after reperfusion is clinically indicated to cause reperfusion injury whereas excessive intracellular calcium ion overload is experimentally proved as a key mechanism of reperfusion injury. We hypothesized that technetium-99m ((99m)Tc) pyrophosphate (Tc-PYP) uptake in injured but viable infarct-related myocardium with preserved myocardial perfusion after reperfusion estimated by thallium-201 ((201)Tl) uptake would be associated with final functional recovery. METHODS: Dual-isotope Tc-PYP/(201)Tl single-photon emission computed tomography (SPECT) was performed 2 days after successful reperfusion therapy in patients with first acute myocardial infarction, and 50 patients (63 +/- 13 years old, female 22%) with preserved (201)Tl uptakes of > or = 50% in reperfused myocardium was followed for 1 month. Tc-PYP uptake was assessed as the heart-to-sternum (H/S) ratio. Two-dimensional echocardiography was also performed 2 days and 1 month after reperfusion to evaluate functional recovery. RESULTS: High Tc-PYP uptake, defined as the H/S ratio > or = 0.81, was predictive of chronic phase no functional recovery (73.7% in 14 of 19 patients with high uptake vs 16.1% in five of 31 patients without those, p < 0.0001). After adjustment for potential confounding variables, including electrocardiographic persistent ST segment elevation at 1 h after reperfusion, high Tc-PYP uptake remained independently predictive of no functional recovery with odds ratio of 8.7 (95% confidential interval = 2 to 38.7; p = 0.005). CONCLUSION: High Tc-PYP uptake in reperfused but viable infarct-related myocardium was a powerful predictor of no functional recovery, which may reflect excessive intracellular calcium ion overload caused by reperfusion injury. Tc-PYP/(201)Tl dual-isotope SPECT imaging can provide prognostic information after reperfusion.

Scintographic evidence of severe myocardial hypoperfusion in a patient with left anterior descending coronary artery bridging--case report and review of the literature.

Myocardial bridging is a congenital abnormality characterized by an intramyocardial course of a major epicardial coronary artery segment. Generally considered a benign condition, myocardial bridging has been associated with angina, acute myocardial infarction, and sudden death. Herein, we report a patient with an intramyocardial segment in the mid portion of the left anterior descending coronary artery with marked systolic compression. Single photon emission computed tomography with technetium-99m tetrofosmin done to evaluate an episode of chest pain showed a large predominantly fixed perfusion defect in the mid to apical anterior wall with partial reversibility. The patient's chest pain did not recur and repeat single photon emission computed tomography imaging 14 days later with rest-redistribution thallium-201 showed normal myocardial perfusion. The overall clinical impression was that myocardial bridging resulted in severe transient anterior myocardial hypoperfusion. The literature on prevalence, diagnosis, use of perfusion imaging, and hemodynamic effects of myocardial bridging is reviewed.

Odor detection ability and thallium-201 transport in the olfactory nerve of traumatic olfactory-impaired mice.

Although olfactory nerve damage is a contributing factor in the diagnosis of posttraumatic olfactory loss, at present, there are no methods to directly assess injury to these nerves. We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. To determine if olfactory function after nerve injury could be assessed with nasal administration of 201 Tl, we measured the correlation between odor detection ability (ODA) and the rate of transport of 201 Tl in olfactory nerves. Both ODA and 201 Tl transport were measured after bilateral olfactory nerve transection for a 4-week period. Cycloheximide solution was used for ODA against tap water. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry. There was a significant correlation between ODA and the rate of 201 Tl transport in the olfactory nerve. These findings suggest that olfactory function after nerve injury can be objectively evaluated with the nasal administration of 201 Tl.