Reproducibility of Tl-201 and Tc-99m sestamibi gated myocardial perfusion SPECT measurement of myocardial function

BACKGROUND: We compared the reproducibility of thallium 201 and technetium 99m sestamibi (MIBI) gated single photon emission computed tomography (SPECT) measurement of myocardial function using the Germano algorithm (J Nucl Med 1995;36:2138-47). METHODS AND RESULTS: Gated SPECT acquisition was repeated in the same position in 30 patients who received Tl-201 and in 26 who received Tc-99m-MIBI. The quantification of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) on Tl-201 and Tc-99m-MIBI gated SPECT was processed independently with Cedars-Sinai QGS (Quantitative Gated SPECT) software. The reproducibility of the measurement of ventricular function on Tl-201 gated SPECT was compared with that of Tc-99m-MIBI gated SPECT. Correlation between the 2 measurements for volumes and EF was excellent for the repeated gated SPECT studies of Tl-201 (r = 0.928 to 0.986, P <.05) and Tc-99m-MIBI (r = 0.979 to 0.997, P <.05). However, Bland-Altman analysis revealed the 95% limits of agreement (2 SDs) for volumes and EF were narrower by repeated Tc-99m-MIBI gated SPECT (EDV 14.1 mL, ESV 9.4 mL, EF 5.5%) than by repeated Tl-201 gated SPECT (EDV 24.1 mL, ESV 18.6 mL, EF 10.3%). The root-mean-square values of the coefficient of variation for volumes and EF were smaller by repeated Tc-99m-MIBI gated SPECT (EDV 2.1 mL, ESV 2.7 mL, EF 2.3%) than by repeated Tl-201 gated SPECT (EDV 3.2 mL, ESV 3.5 mL, EF 5.2%). CONCLUSIONS: QGS provides an excellent correlation between repeated gated SPECT with Tl-201 and Tc-99m-MIBI. However, Tc-99m-MIBI provides more reproducible volumes and EF than Tl-201. Tc-99m-MIBI gated SPECT is the preferable method for the clinical monitoring of ventricular function.     

Comparison of Tc-99m sestamibi and Tl-201 gated perfusion SPECT

BACKGROUND: To determine the interpretability of gated thallium-201 perfusion SPECT compared with that performed by use of technetium-99m sestamibi (MIBI), 33 patients with prior myocardial infarction were studied. Patients received 22 to 30 mCi (814 to 1110 MBq) MIBI at peak stress, and a 15-minute gated SPECT acquisition was begun 30 to 40 minutes thereafter. On a subsequent day gated Tl-201 SPECT was acquired for 15 minutes, 4 hours after a resting 3.5 mCi (130 MBq) injection. SPECT was performed over a 180-degree arc by use of a 90-degree angled 2-detector camera. RESULTS: Gated studies were interpreted independently by 4 experienced physicians. Study quality was graded (0 = uninterpretable to 4 = excellent). Wall motion (0 = normal to 2 = akinetic/dyskinetic) and wall thickening (0 = normal to 2 = absent) were graded for each of 10 segments viewed in orthogonal planes. Left ventricular ejection fraction (LVEF) was calculated by use of software thus far validated only for MIBI. The average count density of mid-ventricular end-diastolic short axis tomograms with sestamibi was 3.47 times greater than with thallium. Mean study quality was 3.4 for MIBI and 1.8 for thallium (P < 10(-6)). No gated MIBI SPECTs, but 2 gated thallium studies (6%) were judged uninterpretable. Among interpretable scans, interobserver agreement (Kendall statistic) in assessing wall motion was 0.73 for MIBI and 0.66 for thallium (P = .01). For assessing wall thickening, the Kendall statistic was 0.73 for MIBI and 0.69 for thallium (P = .05). Correlation (r) of LVEFs was 0.91, SEE = 6.4. CONCLUSIONS: We conclude that gated thallium SPECT is inferior to MIBI because of much poorer image quality and somewhat poorer interobserver agreement among experienced physicians. However, LVEF can be determined reliably from gated thallium SPECT.     

Discordant Tl-201 and Tc-99m imaging in a patient with thyroid carcinoma and Hashimoto's disease

In a case of Hashimoto's disease complicated by thyroid gland cancer, the primary site of the cancer was visualized as a cold nodule on Tc-99m pertechnetate scintigraphy, as a warm nodule on Tl-201 early imaging, and as a hot nodule on Tl-201 delayed imaging. Generally, Tl-201 shows markedly diffuse accumulation in the lesions of Hashimoto's disease. The warm nodules observed on early scans suggested similar accumulation at the sites of Hashimoto's disease and thyroid cancer. The hot nodules on delayed imaging may be due to the difference in Tl-201 washout time between the sites of Hashimoto's disease and thyroid cancer. There was markedly increased Tl-201 accumulation in bilateral cervical metastatic lymph nodes on both early and delayed images.     

Tc-99m-N-MPO: Novel cationic Tc-99m radiotracer for myocardial perfusion imaging

Background. Technetium 99m-N-MPO ([Tc-99m-N(mpo)(PNP5)]⁺) is a cationic Tc-99m nitrido complex. The objective of this study is to evaluate its potential as a new radiotracer for myocardial perfusion imaging. Methods and Results. Biodistribution studies were performed in Sprague-Dawley rats and guinea pigs to compare the myocardial uptake and excretion kinetics of Tc-99m-N-MPO from noncardiac organs, such as the liver and lungs, with those of the known cationic Tc-99m radiotracers: Tc-99m-N-DBODC5 and Tc-99m-sestamibi. Planar imaging was performed in Sprague-Dawley rats to evaluate the utility of Tc-99m-N-MPO as a myocardial perfusion imaging agent. Metabolism studies were carried out by use of both Sprague-Dawley rats and guinea pigs. In general, the heart uptake of Tc-99m-N-MPO was between that of Tc-99msestamibi and Tc-99m-N-DBODC5 over the 2-hour study period. However, the heart-liver ratio of Tc-99m-N-MPO (12.75±3.34) at 30 minutes after injection was more than twice that of Tc-99m-N-DBODC5 (6.01±1.45) and approximately 4 times higher than that of Tc-99msestamibi (2.90±0.22). The heart uptake and heart-liver ratio of Tc-99m-N-MPO and Tc-99m-sestamibi in guinea pigs were significantly lower than those obtained in Sprague-Dawley rats. The metabolism studies demonstrated no detectable Tc-99m-N-MPO metabolites in the urine and feces samples of the Sprague-Dawley rats at 120 minutes after injection. In guinea pigs no Tc-99m-N-MPO metabolites were detected in the urine at 120 minutes, but only approximately 60% of Tc-99m-N-MPO remained intact in the feces samples. In contrast, there was no intact Tc-99m-sestamibi detected in urine samples, and less than 15% of Tc-99m-sestamibi remained intact in the feces samples. Planar imaging studies indicated that clinically useful images of the heart may be obtained as early as 15 minutes after injection of Tc-99m-N-MPO. Conclusion. The combination of favorable organ biodistribution and myocardial uptake with rapid liver clearance makes Tc-99m-N-MPO a very promising myocardial perfusion radiotracer worthy of further evaluation in various preclinical animal models. This work was supported, in part, by Purdue University and the following research grants: R01 CA115883 A2 (S.L.) from the National Cancer Institute, BCTR0503947 (S.L.) from the Susan G. Komen Breast Cancer Foundation, AHA0555659Z (S.L.) from the Greater Midwest Affiliate of the American Heart Association, R21 EB003419-02 (S.L.) from the National Institute of Biomedical Imaging and Bioengineering, and R21 HL083961-01 from the National Heart, Lung, and Blood Institute.     

Concordant uptake of Tc-99m sestamibi and Tl-201 in unsuspected breast tumor.

An unsuspected breast tumor was discovered in a 65-year-old woman referred for evaluation of possible ischemic heart disease. Marked tumor uptake of Tl-201 and concordant but less intense uptake of Tc-99m sestamibi (Tc-99m MIBI) was observed after both planar and SPECT imaging post treadmill exercise. Although many reports in the literature document Tl-201 tumor uptake, this is much less frequently reported with Tc-99m MIBI at this time. To the authors' knowledge, Tc-99m MIBI breast tumor uptake has not been reported to date. Tc-99m MIBI might prove useful in the detection of primary and metastatic breast carcinoma, and warrants further investigation.     

Tl-201 and Tc-99m HMDP scintigraphic findings in extraskeletal osteosarcoma

Extraskeletal osteosarcoma is an extremely rare high-grade malignant soft tissue tumor, which accounts for approximately 4% of osteosarcomas and less than 1% of all soft tissue sarcomas. There have been reports describing the scintigraphic findings of this tumor, especially with Tl-201. We report a biopsy-proven case of extraskeletal osteosarcoma in which the bone and thallium scans were found to be useful in monitoring chemotherapy response. The Tc-99m HMDP bone scan revealed increased extraskeletal uptake in the tumor.     

The prognosis of a normal stress-only Tc-99m myocardial perfusion imaging study

Background  

Stress-only imaging saves time and radiation exposure, but apprehension remains about the reliability, diagnostic, and prognostic accuracy of a normal stress-only study. The objective of this study was to determine the prognosis of stress-only SPECT MPI in routine clinical practice.     

用201Tl与99Tcm-HL91双核素显像评价心脏病患者心肌灌注与乏氧

目的用201Tl与99Tcm-4,9-二氮-3,3,10,10-四甲基十二烷-2,11-二酮肟(HL91)同时评价心脏病患者心肌灌注与乏氧.方法22例心脏病患者及9例临床诊断正常者行10 min、3和24 h延迟201Tl与99Tcm-HL91双核素心肌显像,用5分法评价图像质量,用17节段法分析201Tl显像缺损与乏氧显影心肌节段.结果双核素显像中99Tcm-HL91显像图质量不如201Tl(P＜0.01);80.85%(38/47个节段)的急性心肌梗死患者201Tl灌注缺损心肌节段在99Tcm-HL91显像中显影,乏氧显影心肌节段数明显多于201Tl灌注缺损节段数;陈旧性心肌梗死201Tl、99Tcm-HL91均不显影的符合率为85.71%.结论201Tl与99Tcm-HL91双核素心肌显像能同时提供判断心肌血流灌注与乏氧的信息.     

Focal pulmonary uptake during Tc-99m myocardial perfusion SPECT imaging

PURPOSE: To evaluate the incidence and origin of abnormal focal pulmonary uptake during myocardial perfusion SPECT imaging (MSPECT). METHODS: For evaluation of chest pain, 790 men and 581 women (mean age, 56 +/- 13 years) underwent MSPECT. All of them received adenosine for pharmacologic stress and Tc-99m tetrofosmin (TF, n = 817) or Tc-99m sestamibi (MIBI, n = 554) for myocardial perfusion imaging. RESULTS: Review of chest radiography with or without computed tomography revealed 111 (8.1%) focal pulmonary diseases. Among them, 38 (34.2%) showed focal pulmonary uptake (TF, 22; MIBI, 16); 27 (30.7%) of 88 showed previous pulmonary tuberculosis; 2 of 10 (20%) benign pulmonary nodules; 4 of 5 (80%) metastatic lung cancers; 2 of 4 (50%) primary lung cancers; and 3 of 4 (75%) pneumonias. No difference in uptake was noted for the two imaging agents. Intensity of uptake did not vary with origin of the uptake. Focal abnormal pulmonary uptake was found in 2.8% of patients undergoing MSPECT and in 34.2% of patients in whom radiological examinations showed regional pulmonary disease. In patients with abnormal pulmonary uptake on MSPECT, 16% had a malignant lesion, whereas 75% of patients with a pulmonary nodule shown on radiography and focal pulmonary uptake on MSPECT had a malignant lesion. CONCLUSIONS: Although the incidence of abnormal pulmonary uptake during MSPECT was very low, the incidence of malignant lesions in the patients with nodular pulmonary uptake was relatively high.     

Assessment of myocardial viability using F-18 fluorodeoxyglucose/Tc-99m sestamibi dual-isotope simultaneous acquisition SPECT: Comparison with Tl-201 stress-reinjection SPECT

BACKGROUND: This study compared technetium 99m sestamibi/fluorine 18 fluorodeoxyglucose dual-isotope simultaneous acquisition (DISA) with stress-reinjection thallium 201 single photon emission computed tomography (SPECT) with regard to their ability to detect myocardial viability. METHODS AND RESULTS: The study cohort consisted of 42 angiographically significant coronary artery disease patients with symptomatic congestive heart failure or regional wall motion abnormalities. In total, 398 dysfunctional segments in 40 patients were analyzed (2 patients were excluded because of poor-quality F-18 fluorodeoxyglucose images). Of the segments, 217 were diagnosed as viable and 144 as nonviable by both DISA and Tl-201, 33 were viable by DISA but nonviable by Tl-201, and 4 were viable by Tl-201 but nonviable by DISA. Most discrepancies were in the inferior wall. Of the 40 patients, 16 underwent revascularization. From the follow-up results for the 105 dysfunctional segments in these 16 patients, DISA viability appears to be a significant predicting factor (P = .014) for functional recovery after revascularization statistically whereas Tl-201 viability does not (P = .09). CONCLUSION: Our study suggests that DISA viability provides more accurate prediction of postrevascularization functional recovery than Tl-201 viability. Given the small number of patients who underwent revascularization, the superiority of DISA over Tl-201 in detecting myocardial viability may be firmly established by further study on a large scale for patients with profound left ventricular dysfunction.     

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.     

Observer variability in the evaluation of dual-isotope Tl-201/Tc-99m sestamibi rest/stress myocardial perfusion SPECT in men and women with known or suspected stable angina pectoris

BACKGROUND: Observer variability of dual-isotope myocardial perfusion imaging (MPI) with single photon emission computed tomography has rarely been investigated. The aim of our study was to evaluate the interpretive reproducibility with this technique. METHODS AND RESULTS: We report on 507 patients with known or suspected stable angina who were studied before coronary angiography. A 1-day thallium 201/technetium 99m sestamibi rest/stress MPI protocol was used. MPI was interpreted by 2 independent observers without knowledge of clinical data, using a 20-segment scoring model. By consensus, the overall rate of abnormal MPI was 49% (59% in men and 34% in women). The interobserver agreement for the whole group (kappa = 0.85) and for men and women separately (kappa = 0.86 and 0.82, respectively) was excellent with regard to the overall diagnosis (normal, reversible, or fixed defects) as well as left anterior descending and left circumflex artery vascular territories (kappa = 0.85 and 0.82, respectively). However, in the right coronary artery territory, agreement was excellent in men (kappa = 0.83) but moderate in women (kappa = 0.57). CONCLUSIONS: In a relatively large group of men and women with stable angina pectoris, interpretive reproducibility (overall and individual vessel diagnosis) was excellent, except in the right coronary artery territory of women, in which it was moderate.     

Interpretive reproducibility of stress Tc-99m sestamibi tomographic myocardial perfusion imaging

BACKGROUND: Observer variability has been shown with interpretation of planar thallium-201 images. The interpretive reproducibility of technetium-99m sestamibi tomographic imaging is unknown. This study evaluated the interpretive reproducibility of interpretable Tc-99m sestamibi tomographic images among nuclear cardiologists with a wide range of training and experience. METHODS: Three experienced readers (EX) and 3 less-experienced readers (LEX) interpreted 138 exercise and rest Tc-99m sestamibi tomographic images (101 were abnormal in patients with coronary artery disease [CAD], 37 were normal in patients with <5% likelihood of CAD) twice in random sequence without clinical data. Images of good to excellent quality were randomly selected from a database at 2 nuclear cardiology laboratories. Intraobserver and interobserver agreement for global, left anterior descending (LAD) territory, non-LAD first (normal/abnormal) and second (normal/fixed/reversible) order, and defect extent (normal/single-vessel CAD/multi-vessel CAD) were assessed with percent agreement and Cohen's kappa (kappa) statistic. RESULTS: With regard to intraobserver agreement, first and second order ranged from 87% to 94% and 80% to 90% for global, 82% to 96% and 78% to 95% for LAD, and 88% to 91% and 80% to 90% for non-LAD, respectively. Defect extent ranged from 75% to 90%. There were no differences between EX and LEX for global and non-LAD first and second order, LAD first order, and defect extent. LAD second order was 93% for EX compared with 88% (P = .015) for LEX. With regard to interobserver agreement, first and second order ranged from 73% to 89% and 64% to 85% for global, 73% to 93% and 69% to 91% for LAD, and 76% to 88% and 68% to 84% for non-LAD, respectively. Defect extent ranged from 61% to 82%. Global first and second order ranged from 85% to 87% and 78% to 82% for EX compared with 73% to 84% and 64% to 79% for LEX. LAD first and second order ranged from 89% to 91% and 88% to 89% for EX compared with 73% to 91% and 69% to 70% for LEX. Non-LAD first and second order ranged from 82% to 86% and 76% to 77% for EX compared with 76% to 86% and 68% to 81% for LEX. Defect extent ranged from 69% to 75% for EX compared with 59% to 77% for LEX. CONCLUSIONS: There is moderate to excellent interpretive reproducibility with stress Tc-99m sestamibi SPECT imaging among nuclear cardiologists with a wide range of training and experience.     

Scapular hibernoma fortuitously discovered on myocardial perfusion imaging through Tc-99m tetrofosmin

A 49-year-old man was hospitalized for precordial pain. The result of a resting electrocardiograph was normal. Tc-99m tetrofosmin stress myocardial imaging was performed and uptake in the area of the left scapula was seen. The abnormality was caused by a subcutaneous tumor. Histologic examination revealed a hibernoma.