Thallium-201 Single-photon Emission Computed Tomography Research Articles

NIMG-88. THALLIUM 201 SINGLE PHOTON EMISSION CT (TI-SPECT) FOR DIFFERENTIATION OF MALIGNANT VERSUS BENIGN NERVOUS SYSTEM SPACE OCCUPYING LESIONS: A RETROSPECTIVE STUDY, SYSTEMATIC REVIEW, AND META-ANALYSIS

Abstract Importance Thallium-201 single-photon emission computed tomography (TI-SPECT) imaging has been used historically to distinguish malignant cerebral neoplasms from infectious etiologies. Objectives Our study aims to review existing literature and conduct a retrospective study and meta-analysis on the use of TI-SPECT to differentiate malignant from non-malignant nervous system lesions. Data Sources A retrospective study on use of TI-SPECT in differentiating malignant versus benign nervous system masses was conducted in two tertiary hospitals in the Philippines. Systematic review of relevant studies regarding TI-SPECT for brain and spinal cord lesions was also done. Meta-analysis was performed to generate pooled sensitivity and specificity. Study Selection All study types published in the English language were included – randomized controlled trials (RCTs), prospective/retrospective cohort studies, and case series and reports; abstract only studies were excluded. Studies that involved either pediatric and adult cases were considered. Data Extraction and Synthesis The study complied with the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) Guidelines. Main Outcome and Measure The primary outcome was sensitivity and specificity of TI-SPECT. This involved getting correlation of positive and negative thallium scan uptake with either biopsy results (if available) or diagnosis via clinical response to treatment (i.e. whether cases that were managed as infection or demyelination showed improvement on follow-up). RESULTS: Thirty-two (32) articles were qualitatively described and 25 datasets were subjected to meta-analysis. Pooled sensitivity and specificity were 0.89 (95% CI: 0.82-0.94) and 0.82 (95% CI: 0.74-0.88), respectively with an area under the curve (AUC) for diagnostic accuracy of 0.92. CONCLUSION: and Relevance Thallium scans may be utilized to discriminate malignant from benign nervous system lesions, especially, in cases with a >80% pre-test probability. Further studies are needed to validate this findings.

Assessment of left ventricular volumes and ejection fraction using ultra-low-dose thallium-201 SPECT on a CZT camera: a comparison with magnetic resonance imaging

BackgroundCadmium-Zinc-Telluride (CZT) technology allows use of low activities of radiopharmaceuticals. The aim was to verify the values of left ventricular volume parameters, obtained via ultra-low-dose thallium Single Photon Emission Computed Tomography (SPECT) using a CZT camera. Methods and ResultsForty-five patients referred for an assessment of myocardial perfusion or viability imaging were examined using CZT-SPECT and 1.5 T magnetic resonance (MRI) scanner. The ultra-low-dose protocol with 0.5 Mbq 201-Tl per kg of body weight was used. The values of end-systolic (ESV) and end-diastolic volumes (EDV), left ventricular ejection fraction (EF) and myocardial mass (MM) were assessed using both techniques. A very good correlation was found between the EF, ESV, and EDV values assessed with CZT-SPECT and cardiac magnetic resonance MRI; the Pearson coefficients were 0.86, 0.95, and 0.91, respectively. A moderate correlation was found for myocardial mass, r = 0.57. Compared to MRI, SPECT systematically overestimated ESV and MM, while it underestimates the EF, with P ≤ .001 in all cases. There was no difference in EDV estimation. ConclusionsLeft ventricular volumes and ejection fraction assessed via ultra-low-dose CZT-SPECT showed very good correlation with the values obtained by MRI. A moderate correlation was found for myocardial mass.

Association of QRS duration with left ventricular volume and ejection fraction after anterior myocardial infarction assessed by gated single photon emission computed tomography

Background: Even intermediate QRS prolongation without bundle branch block is associated with worse clinical outcome after myocardial infarction (MI). We assessed the association of QRS duration with left ventricular (LV) volume and ejection fraction after anterior MI by using quantitative gated single photon emission computed tomography (SPECT).Methods: Eighty-two patients with prior anterior MI were enrolled. Intermediate QRS prolongation was defined as QRS duration ≥100 ms without bundle branch block. Quantitative analysis of thallium SPECT was performed on the redistribution image. LV end-diastolic volume (LVEDV), end-systolic volume (LVESV) and ejection fraction (LVEF) were obtained.Results: There were 25 patients with intermediate QRS prolongation and 57 patients with normal QRS duation. Compared to patients with normal QRS duration, patients with intermediate QRS prolongation had larger LVEDV (137.4 ± 75.1 ml vs 87.9 ± 43.6 ml, p = .004), larger LVESV (89.9 ± 69.6 ml vs 49.2 ± 35.5 ml, p = .009) and lower LVEF (39.3 ± 14.6% vs 47.6 ± 12.0%, p = .02). QRS duration was positively associated with LVEDV (r = 0.49, p < .001) and LVESV (r = 0.47, p < .001), and was inversely associated with LVEF (r= −0.32, p < .001). Multivariate analysis showed that male sex (β = 0.22, p = .04), QRS duration (β = 0.34, p = .002) and number of abnormal Q waves (β = 0.37, p < .001) were associated with LVEDV. QRS duration (β= −0.32, p = .003) and number of abnormal Q waves (β = −0.40, p < .001) were associated with LVEF.Conclusions: Our results suggest that QRS duration as well as number of abnormal Q waves is independently associated with LV volume and ejection fraction after anterior MI.

Clinical Utility of Thallium-201 Single Photon Emission Computed Tomography and Cerebrospinal Fluid Epstein-Barr Virus Detection Using Polymerase Chain Reaction in the Diagnosis of AIDS-Related Primary Central Nervous System Lymphoma.

Objective: To determine the diagnostic efficiency of thallium-201 single photon emission computed tomography (SPECT) and Epstein-Barr virus (EBV) polymerase chain reaction (PCR) in the differentiation of primary central nervous system lymphoma (PCNSL) from other central nervous system processes in patients with HIV/AIDS.Design/Methods: Over 10 years, 68 thallium-201 SPECT scans were performed on neurologically symptomatic HIV+ patients with focal lesions on CT or MRI at the Johns Hopkins Hospital. Diagnoses were then established by either autopsy, biopsy, or clinical response to anti-toxoplasmosis therapy. Patients were categorized prior to a prospective clinical reading of the SPECT scans by nuclear medicine physicians.Results: In our patient sample overall, the diagnostic efficiency of thallium-201 SPECT was 79%. The diagnostic accuracy of EBV PCR testing alone in a subset of 22 patients in our study that had CSF analyzed was 73%. However, when both positive EBV PCR and positive thallium-201 SPECT results were used together, the diagnostic accuracy improved to 100% based on a sample of 13 patients where EBV PCR and SPECT imaging results were concordant. Conclusion: Thallium-201 SPECT has a relatively high positive predictive value with regards to the diagnosis of PCNSL, which suggests that patients with positive results could undergo empiric radiation treatment without resorting to brain biopsy. However, the predictive value can be increased by testing for CSF EBV using PCR. Alternatively, if CSF cannot be safely obtained because of mass effect, we believe that these data still suggest that empiric radiation treatment should be considered when discussing treatment options with patients with a positive thallium-201 SPECT.

Quantification of the myocardial area at risk using coronary CT angiography and Voronoi algorithm-based myocardial segmentation

The purpose of this study was to estimate the myocardial area at risk (MAAR) using coronary computed tomography angiography (CTA) and Voronoi algorithm-based myocardial segmentation in comparison with single-photon emission computed tomography (SPECT). Thirty-four patients with coronary artery disease underwent 128-slice coronary CTA, stress/rest thallium-201 SPECT, and coronary angiography (CAG). CTA-based MAAR was defined as the sum of all CAG stenosis (>50%) related territories (the ratio of the left ventricular volume). Using automated quantification software (17-segment model, 5-point scale), SPECT-based MAAR was defined as the number of segments with a score above zero as compared to the total 17 segments by summed stress score (SSS), difference (SDS) score map, and comprehensive SPECT interpretation with either SSS or SDS best correlating CAG findings (SSS/SDS). Results were compared using Pearson's correlation coefficient. Forty-nine stenoses were observed in 102 major coronary territories. Mean value of CTA-based MAAR was 28.3 ± 14.0%. SSS-based, SDS-based, and SSS/SDS-based MAAR was 30.1 ± 6.1%, 20.1 ± 15.8%, and 26.8 ± 15.7%, respectively. CTA-based MAAR was significantly related to SPECT-based MAAR (r = 0.531 for SSS; r = 0.494 for SDS; r = 0.814 for SSS/SDS; P < 0.05 in each). CTA-based Voronoi algorithm myocardial segmentation reliably quantifies SPECT-based MAAR. • Voronoi algorithm allows for three-dimensional myocardial segmentation of coronary CT angiography • Stenosis-related CT myocardial territories correlate to SPECT based area at risk • CT angiography myocardial segmentation may assist in clinical decision-making.

Cost analysis favours SPECT over PET and CTA for evaluation of coronary artery disease: the SPARC study.

There are many ways to perform noninvasive testing in patients with coronary artery disease (CAD), including myocardial perfusion imaging with single-photon emission computed tomography (SPECT), positron-emission tomography (PET), and coronary computed tomography angiography (CTA). Results from series of patients evaluated with single modalities have already been published by many researchers [1–3], but there are few head-to-head comparisons of the outcomes of alternative test strategies [4, 5]. Consequently, the comparative effectiveness of different noninvasive cardiac testing strategies has been difficult to assess. The recently published SPARC registry (Study of Myocardial Perfusion and Coronary Anatomy Imaging Roles in Coronary Artery Disease) in JACC by the group of DiCarli et al. (Stanford, CA, USA) was a multicentre study designed to collect standardised clinical data on patients undergoing CTA, PET, or SPECT [6]. The primary purpose of the SPARC study was to evaluate the economic outcomes of using CTA, PET, or SPECT to evaluate patients with suspected CAD. The authors used an observational registry of 1703 patients: 590 patients underwent CTA, 548 patients had PET and 565 patients SPECT for diagnosis of suspected CAD. Patients were followed for 2 years; documented resource use, medical costs for CAD, and clinical outcomes were assessed. The main findings were that costs were significantly lower for SPECT compared with CTA or PET in the evaluation of suspected CAD. SPECT was economically attractive compared with PET, whereas CTA was associated with higher costs and no significant difference in mortality compared with SPECT. More specifically, the authors observed that patients who underwent coronary CTA and PET experienced higher rates of subsequent invasive coronary arteriography (16 % and 15 %, respectively) as compared with patients who underwent SPECT (7 %). The mean total radiation was significantly higher for CTA (15.1 mSV) compared with SPECT (11.7 mSV), both for the initial tests (13 mSV vs. 11 mSV) and for follow-up tests and procedures (2.1 mSV vs. 0.7 mSV). Exposure from follow-up tests and procedures was higher after PET (2.0 mSV) than after SPECT (0.6 mSV). The findings in favour of SPECT are in line with a decision model by Garber and Solomon [7], who compared exercise treadmill testing, stress echocardiography, planar thallium imaging, SPECT, and PET imaging with a strategy of immediate invasive angiography. They found SPECT to be much more cost-effective than PET for noninvasive diagnosis, and SPECT to be a better option than immediate invasive coronary angiography. In terms of outcomes, Shaw et al. [1] found that patients who underwent initial SPECT with selective cardiac catheterisation had lower costs than patients who underwent routine coronary angiography (END study). In the EMPIRE study by Underwood et al. [2] it was demonstrated that strategies using myocardial perfusion imaging were cheaper and equally effective when compared with strategies that did not use myocardial perfusion imaging, both for the cost of diagnosis and for overall 2-year management costs; the 2-year patient outcome was the same. Sharples et al. [8] randomised 898 patients to SPECT, stress echocardiography, magnetic resonance imaging (MRI), or direct invasive coronary angiography, and found SPECT to be as useful as immediate invasive angiography with similar costs. A limitation of the SPARC study is the fact that MRI was not included in the comparative strategies. In addition, as the study started in 2006, in recent years many technological revolutions have taken place for all imaging modalities indicating that studies such as SPARC should be repeated and extended every 5–10 years [9]. Analysis of the current SPARC registry at least suggests that SPECT is the noninvasive imaging procedure of choice to evaluate patients with suspected CAD in terms of subsequent medical costs. SPECT offered the lowest costs over 2 years of follow-up among patients with suspected CAD. The significantly higher costs among patients undergoing CTA or PET were primarily due to higher rates of subsequent invasive cardiac procedures, because there was little difference in initial costs of testing. To conclude, the use of SPECT myocardial perfusion imaging was associated with lower costs over 2 years of follow-up than the use of CTA or PET, primarily because of fewer subsequent invasive procedures. Consequently, SPECT imaging seems to be the preferred imaging strategy in patients with suspected CAD. The value of SPECT imaging has been underscored by several recent reports [10–13]. However, larger and more definitive studies, such as the ongoing PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial (NCT01174550), are needed to assess the value and cost effectiveness of the various noninvasive imaging strategies.

Clinical Value of Preoperative Coronary Risk Assessment by Computed Tomographic Arteriography Prior to Adult Living Donor Liver Transplantation

PurposePatients with advanced liver diseases are at increased risk of cardiovascular events, resulting in a higher incidence of cardiac complications following liver transplantation (OLT). We assessed the clinical value of computed tomographic coronary arteriography (CTCAG) as a routine preoperative cardiac evaluation test in adult patients scheduled for living donor OLT (LDLT). MethodsThis single-center, prospective, observational study evaluated 247 adult patients being assessed for LDLT from April 2010 to March 2011. CTCAG was performed in patients with all-negative findings on routine cardiac workup, including thallium single photon emission computed tomography (SPECT). ResultsOf the 247 patients evaluated, 27 (10.9%) showed abnormal findings on CTCAG, with 18 (7.3%) showing mild to moderate involvement of one vessel; 7 (2.8%), two-vessel; and 2 (0.8%), three-vessel involvement. Coronary artery calcification was identified in patients with significant coronary artery stenosis. No adverse events occurred after CTCAG. Noticeable hypotensive episodes during LDLT surgery occurred in 5% of patients, mostly related to massive bleeding or postperfusion syndrome. During the first 3 months after LDLT, 3% of patients showed stress cardiomyopathy, but all recovered with supportive care. ConclusionsThe poor general medical condition of LDLT candidates and the diagnostic accuracy of CTCAG suggest that this test should be included in the routine pretransplant cardiac workup, along with thallium SPECT, for these patients.

MRI and thallium-201 SPECT in the prediction of survival in glioma

This paper aims to study the value of MRI and Thallium 201 ((201)Tl) single-photon emission computed tomography (SPECT) in the prediction of overall survival (OS) in glioma patients treated with temozolomide (TMZ) and to evaluate timing of radiological follow-up. We included patients treated with TMZ chemoradiotherapy for newly diagnosed glioblastoma multiforme (GBM) and with TMZ for recurrent glioma. MRIs and (201)Tl SPECTs were obtained at regular intervals. The value of both imaging modalities in predicting OS was examined using Cox regression analyses. Altogether, 138 MRIs and 113 (201)Tl SPECTs in 46 patients were performed. Both imaging modalities were strongly related to OS (P ≤ 0.02). In newly diagnosed GBM patients, the last follow-up MRI (i.e., after six adjuvant TMZ courses) and SPECT (i.e., after three adjuvant TMZ courses) were the strongest predictors of OS (P = 0.01). In recurrent glioma patients, baseline measurements appeared to be the most predictive of OS (P < 0.01). The addition of one imaging modality to the other did not contribute to the prediction of OS. Both MRI and (201)Tl SPECT are valuable in the prediction of OS. It is adequate to restrict to one of both modalities in the radiological follow-up during treatment. In the primary GBM setting, MRI after six adjuvant TMZ courses contributes significantly to the prediction of survival. In the recurrent glioma setting, baseline MRI appears to be a powerful predictor of survival, whereas follow-up MRIs during TMZ seem to be of little additional value.

201-Thallium SPECT Could Predict the Prognosis of Dilated Phase of Hypertrophic Cardiomyopathy

Purpose: Although dilated phase of hypertrophic cardiomyopathy (D-HCM) is recognized to have a poor prognosis, there are some D-HCM patients who survive for a long period. The purpose of this study was to investigate whether thallium-201 single photon emission computed tomography (Tl-SPECT) could predict the prognosis in patients with D-HCM. Methods: We studied the relationship between the degree of myocardial perfusion defects on Tl-SPECT and the prognosis in patients with D-HCM. For analysis of Tl-SPECT, semiquantitative 20-segment visual interpretation was performed using a 5-point scoring system and the summed rest scores (SRS) was obtained.

Left Ventricular Long-Axis Function During Dobutamine Stress Echocardiography for the Prediction of Post- Revascularization Recovery: Comparison with SPECT Thallium Scintigraphy

Aim: Το compare echocardiographic left ventricular (LV) long axis function and single photon emission computed tomography (SPECT) thallium-201 scintigraphy for the prediction of recovery of LV dyssynergies after revascularization. Methods: Thirty patients with a history of previous myocardial infarction and LV dysfunction underwent a transthoracic echocardiographic study before and after successful revascularization (101±14 days), in order to evaluate post-revascularization recovery of asynergic myocardial walls. In these patients and in 25 ageand sex-matched healthy subjects, an additional study during dobutamine infusion was also performed. All subjects also underwent SPECT thallium-201 scintigraphy. Prior and during dobutamine infusion the LV systolic atrioventricular (AV) plane displacement was recorded from the apical four and two chamber views, by M-Mode, at four LV sites, corresponding to the septal, lateral, anterior and inferior walls. Results: Healthy subjects showed a significant increase in AV displacement at all LV sites during dobutamine infusion (p 0.05). Selecting a maximum LV systolic AV displacement increase of >2 mm, the method proved to have a sensitivity of 91%, specificity of 83%, positive predictive value of 88% and negative predictive value of 87%. When SPECT thallium scans were used, the above indices were 86%, 65%, 74% and 79% respectively. Conclusion: The assessment of LV long axis function with the measurement of left systolic AV plane displacement during dobutamine infusion constitutes a simple and accurate method, better than SPECT thalium images, for the prediction of recovery of LV asynergy after revascularization. Euroclinic Hospital, Athens, Greece Nikaia General Hospital, Piraeus, Greece 1 Department of Cardiology, Evagelismos Hospital, Athens, Greece 2 Department of Cardiology, University of Athens, Attikon Hospital, Athens, Greece Agia Varvara Hospital, Athens, Greece

Lack of Association between Small Dense Low-Density Lipoprotein Levels and Coronary Artery Disease in Chronic Hemodialysis Patients

Background/Aims: Small, dense low-density lipoprotein (sd-LDL) is a newly recognized risk factor for coronary artery disease (CAD) in the general population. This study was performed to evaluate the relationship between sd-LDL, and CAD and cardiovascular risk factors such as other lipid profiles and hemostatic factors, in patients with chronic hemodialysis (CHD). Methods: Thallium single-photon emission computed tomography (SPECT) was performed to evaluate for CAD in 126 CHD patients. Coronary angiography was performed in patients with positive thallium SPECT. CHD patients were classified into CAD and non-CAD group. LDL subfractions, other lipid profiles, and hemostatic factors were measured. Results: The proportion of sd-LDL, and mean LDL size did not differ between CHD patients and healthy controls. Twenty-eight CHD patients had CAD by thallium SPECT and coronary angiography. The proportion of sd-LDL and mean LDL size did not differ between CAD and non-CAD patients. Age, diabetes mellitus presentation and high-sensitivity C-reactive protein (hs-CRP) levels were significantly higher, and prealbumin and apolipoprotein A1 levels were significantly lower, in the CAD group (p < 0.05). The proportion of sd-LDL was positively correlated with triglyceride levels (p < 0.001), apolipoprotein B (p < 0.05) and fibrinogen (p < 0.05). Conclusion: This study showed that sd-LDL is not increased in CHD patients and is not associated with CAD in such patients.

Thallium-201 and I-123 Beta-Methyl Iodophenyl-Pentadecanoic Acid Dual Isotope Single Photon Emission Computed Tomography for Evaluating Reperfusion Injury After Successful Reperfusion Therapy

We report a reperfusion injury after rotational coronary atherectomy (RA) in a 66-year-old man with coronary artery disease. Submaximal exercise with thallium-201 single photon emission computed tomography (SPECT) imaging before reperfusion showed partially reversible perfusion defects in the apex and reversible perfusion defects in the anteroseptal area. Thallium-201 and I-123 beta-methyl iodophenyl-pentadecanoic acid (BMIPP) dual isotope SPECT was performed 5 days before and 1 hour after RA, and 1 month after RA. SPECT images at 1 hour after recovery of no reflow phenomenon after RA revealed enlargement of the defect sizes on thallium-201 and BMIPP uptakes in the anteroseptal area including the apex compared with those before RA. The defect size of thallium-201 uptake was progressively improved on 5 hour delayed redistribution imaging and 1 month after reperfusion compared with that of BMIPP uptake. In conclusion, the changes for the worse of thallium-201 uptake and fatty acid metabolism immediately after the no reflow phenomenon may indicate an injured membrane integrity with altered myocardial metabolism rather than myocardial ischemia. Thallium-201 and I-123 BMIPP dual isotope SPECT is useful for evaluating reperfusion injury after successful reperfusion therapy in a patient with acute coronary syndrome.

Frequency of Silent Myocardial Ischemia Detected by Thallium-201 SPECT in Patients with Type 2 Diabetes

Background: Silent myocardial ischemia (SMI) is more common in diabetic patients than among the general population. It is not yet established whether a routine screeni ng test for SMI is necessary, and which screening test would be most useful. The purpose of this study was to estimate the prevalence of SMI detected by Thallium-201 perfusion single photon emission compu ted tomography (SPECT) in type 2 diabetic patients. Methods: A total of 173 asymptomatic type 2 diabetic patients were included in the study. Thallium-201 perfusion SPECT was performed to screen for SMI. Results: Among the 173 patients, abnormal perfusion patterns were found in 11 patients. Coronary angiography was carried out for these patients, and significant coronary artery stenosis was found in ten of them (positive predictive value; 90.9%). There was a significant association between SMI and overt albuminuria (OR = 7.33, 95% CI, 1.825-29.437). Conclusion: Thallium-201 perfusion SPECT is not sensitive enough to identify SMI, but is accurate in detecting decreased myocardial perfusion. This may be a useful screening tool for detecting SMI in type 2 diabetic patients with impaired renal function. (Korean Diabetes J 33:225-231, 2009)

Direct comparison of thallium-201 and technetium-99m MIBI SPECT of a glioma by receiver operating characteristic analysis

The diagnostic value of single photon-emission computed tomography (SPECT) has been assessed using arbitrarily determined sensitivity and specificity cut-off values. The diagnostic accuracy of thallium-201 (Tl-201) SPECT and technetium-99m methoxyisobutylisonitrile (Tc-MIBI) SPECT were compared for patients with primary glioma using receiver operating characteristic (ROC) analysis. The study population included 59 patients with gliomas. Tl and Tc-MIBI SPECT images were obtained using a multi-detector SPECT machine 15 min (early) and 3 hours (delayed) after intravenous injection of 74 MBq of Tl-chloride or 740 MBq of Tc-MIBI. The regions of interest were set on the tumor and contralateral normal white matter and tumor : normal ratios were calculated. The area z-score (A z) values were calculated from the areas under the ROC curves. All A z values were high and no statistical difference was observed between the two modalities. Both Tl and Tc-MIBI SPECT are useful imaging modalities for the evaluation of glioma malignancy.

Usefulness of triple-phase thallium-201 SPECT in non-small-cell lung cancer (NSCLC): association with proliferative activity

The conventional delayed scan in dual phase of thallium-201 ((201)Tl) single-photon emission computed tomography (SPECT) is useful for estimating the viability of non-small-cell lung cancer (NSCLC). However, the influence of tumor blood flow cannot be ignored by the scan at 4 h after the tracer injection. For the purpose of improving the diagnostic capability and for clarifying the association between (201)Tl uptake and proliferative activity, we investigated the usefulness of super-delayed scan obtained at 24 h in triple-phase (201)Tl SPECT. A total of 122 patients with lung nodule, 106 of NSCLC and 16 of benign nodule, were given (201)Tl SPECT before the tumor resection. Early image (15 min), delayed image (4 h), and super-delayed image (24 h) were obtained after intravenous injection of (201)Tl chloride (111 MBq). On the each SPECT image, regions of interest (ROIs) were placed over the tumor contour (T) and contra-lateral normal lung tissue (N) area on one transverse view clearly defined lesions, and T/N ratio on the early image (ER), the delayed image (DR), and the super-delayed image (sDR), and retention indexes (RI and sRI) were calculated. All patients underwent subsequent surgical excision, and the specimens were immunostained for Ki-67 and CD34. The proliferative capability was measured as a percentage of positive nuclear area for Ki-67 (MIB-1 index). The angiogenesis was measured density of positive micro-vessels for CD34 (micro-vessel density, MVD). Correlation analysis was performed to evaluate the relationship between the MIB-1 index, MVD, and SPECT parameters. The diagnostic accuracy of sDR in the differential of NSCLC was higher than that of DR (83.6% vs. 91.8%). Both DR and sDR were positively correlated with MIB-1 index. The correlation coefficient was higher in sDR (0.53 vs. 0.69). The MIB-1 index of the increasing pattern (RI < sRI) group was significantly higher (P < 0.001) than that of the decreasing pattern (RI > sRI) group. The super-delayed scan in the triple-phase (201)Tl SPECT is more useful than conventional delayed scan for both the diagnostic capability and assessing proliferation of NSCLC.

Quantitative Analysis of Echocardiographic Cine-Loops Using a 2D-Strain Algorithm in Correlation with Thallium-201 SPECT Imaging

The aim of this study was to investigate the correlation between the regional left ventricular (LV) contractility, assessed by two-dimensional (2D)-strain echocardiographic images, and regional LV perfusion, determined by thallium-201 single photon emission computed tomography (SPECT) imaging. Forty-five hospitalized patients with suspected myocardial ischemia (32 males, mean age 69 ± 12 years) have undergone both echocardiography and SPECT imaging on the same day. The echocardiographic data has been obtained in three apical views. The data for each view has been processed by the 2D-strain algorithm, to produce six peak systolic longitudinal strain measurements per view, one per segment. The resulting measurements have been compared with the corresponding regions within the SPECT bull's-eye map (at rest). In order to handle inaccuracies in the positioning of the echocardiographic transducer, the two datasets have undergone registration based on local correlation. The mean correlation coefficients between SPECT perfusion and peak systolic longitudinal strain for the apical long-axis, apical two-chamber, and apical four-chamber views were 0.55 ± 0.36, 0.47 ± 0.35, and 0.64 ± 0.30 respectively (negative correlation coefficients have been considered as zero). The overall mean correlation coefficient was 0.56 ± 0.34. The scatter graphs of the average values of perfusion and the strain values showed a nonlinear relation between the two parameters. The average correlation coefficient is comparable to the values reported for the correlation between the average LV function, based on visual analysis of echocardiographic imaging, and the average LV perfusion, based on SPECT imaging. (E-mail: aaronisme@yahoo.com)

Myocardial Ischemia Diagnosed by Dual-Energy Computed Tomography

For decades, dual-energy imaging has been used for tissue differentiation with several x-ray–based imaging modalities, exploiting the fact that the tissues in the human body show different absorption characteristics when penetrated with different x-ray spectra, spectra that are typically generated by different kV settings of the x-ray tube. Recently, dual-source computed tomography (CT) with 2 x-ray tubes and 2 detector arrays mounted in the same gantry has become available.1 After experience with earlier experimental prototypes, this dual-source CT for the first time enables the clinical acquisition of dual-energy CT studies simultaneously with a single scan. We used a dual-source CT scanner (Definition, Siemens, Forchheim, Germany) in dual-energy mode for performing coronary CT angiography in a 74-year–old woman with suspected coronary artery disease and prior abnormal nuclear rest/stress single-photon emission CT (SPECT). The CT scan was acquired with retrospective ECG-gating and the following scan parameters: 330-ms gantry rotation, pitch 0.2, and 32×2×0.6-mm …

Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: Comparison with thallium single photon emission computed tomography and echocardiography

Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities. One hundred one patients with previous MI (62 +/- 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion. By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (kappa value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (kappa value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively. Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Evaluation of undifferentiated carcinoma of nasopharyngeal type with thallium-201 and technetium-99m MIBI SPECT

To determine the value of 201-thallium (201-Tl) and technetium-99m sestamibi (Tc-99m MIBI) single photon emission computed tomography (SPECT) for detecting primary undifferentiated carcinoma of nasopharyngeal type (UCNT), residual/recurrent tissue, and lymph node involvement. SPECT of head and neck was prospectively performed in 46 patients with a history of UCNT (201-Tl in 24 patients, Tc-99m MIBI in 22). CT/MRI findings, clinical follow-up, and pathohistological verification served as a gold standard for calculating sensitivity, specificity, and accuracy of each scintigraphic technique. Tumor-to-background index (T/Bg) was derived when SPECT findings were positive. Sensitivity of 201-Tl SPECT was 87 percent, with 78 percent specificity, 83 percent accuracy, and T/Bg of 4.05 +/- 1.50. Tc-99m MIBI SPECT had 85 percent sensitivity, 78 percent specificity, 82 percent accuracy, and T/Bg of 4.45 +/- 1.27. 201-Tl SPECT and Tc-99m MIBI SPECT are useful for detecting primary UCNT, residual/recurrent disease, and lymph node involvement. This use is particularly valuable after chemoradiotherapy when CT/MRI may be ambiguous.

Thallium-201 SPECT predicts response to intensity-modulated radiation therapy for recurrent oral squamous cell carcinoma

The aim of this study was designed to investigate the usefulness of thallium-201 single photon emission computed tomography (SPECT) in predicting response of intensity-modulated radiation therapy (IMRT) for recurrent oral squamous cell carcinoma (OSCC). Thirty-one patients with histologically proven recurrent OSCC were recruited. Before IMRT, all patients underwent SPECT at 15 min and 120 min after intravenous injection 111 MBq of thallous chloride ((201)Tl). Tumour uptake was measured with the semiquantitative early ratio (ER), delayed ratio (DR), and retention index (RI). The patients were classified into responder (complete response and partial response) and non-responder (stable disease and progressive disease) groups according to the tumour response evaluated by the Response Evaluation Criteria in Solid Tumors guidelines. As comparing DR and RI between the two groups, both parameters were significantly higher in the responder group. When a DR of 1.75 was used as a cutoff value for the responders, the receiver operating characteristic (ROC) analyses revealed sensitivity and specificity of 79% and 75%, respectively. At a cutoff value for the responders of a RI of 78.5%, the ROC analyses showed sensitivity and specificity of 95% and 83%, respectively. Our results suggest that (201)Tl-SPECT, as measured by the DR or RI has clinical potential in predicting response of IMRT for patients with recurrent OSCC. The ROC curve analyses further suggest that RI may be superior to DR in distinguishing responders from non-responders.