Myocardial perfusion imaging with technetium-99m sestamibi in patients with cocaine-associated chest Pain

STUDY OBJECTIVE: To describe the characteristics and outcome in patients presenting to the emergency department with chest pain associated with cocaine use, the majority of whom underwent early rest perfusion imaging. METHODS: From January 1994 to June 1996, 218 patients had 241 ED visits for evaluation of symptoms consistent with myocardial ischemia after cocaine use. High-risk patients (N=25) were admitted directly to the CCU for exclusion of myocardial infarction (MI). Moderate- to low-risk patients (N=216) were promptly injected with technetium-99m sestamibi in the ED and underwent gated myocardial perfusion imaging 60 to 90 minutes later. Moderate-risk patients were observed in the CCU, whereas low-risk patients with negative perfusion imaging results were discharged home directly from the ED. RESULTS: A diagnosis of MI was made in 6 patients, 4 of whom had ECG findings consistent with MI. Of the 216 patients who underwent perfusion imaging, 5 had positive study results, including 2 with MI. None of the 38 patients with negative results after perfusion imaging who were admitted to the CCU had a diagnosis of MI. Only 6 of the 67 patients undergoing stress perfusion imaging had reversible perfusion defects. At 30-day follow-up, there were no cardiac events in patients with negative results after rest perfusion imaging. CONCLUSION: Acute MI is infrequent in patients presenting with cocaine-associated chest pain. Positive results after rest perfusion imaging are uncommon, suggesting that myocardial ischemia is infrequently the cause of cocaine-associated chest pain. Early perfusion imaging may offer an effective alternative to routine CCU admission of patients with cocaine-related cardiac symptoms.     

Adenosine technetium-99m sestamibi myocardial perfusion SPECT in women: Diagnostic efficacy in detection of coronary artery disease

Objectives. This study sought to assess the diagnostic efficacy of adenosine technetium-99m (Tc-99m) sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) in a consecutive series of female patients.Background. The utility of adenosine myocardial perfusion SPECT for the detection of coronary artery disease is not well defined in women because most studies have described a predominantly male population with a high prevalence of coronary artery disease.Methods. Of the 201 consecutive female patients in the study group who had undergone adenosine Tc-99m sestamibi myocardial perfusion SPECT, 130 had coronary angiography within 2 months of the nuclear test, and the other 71 had a low likelihood (<10%, mean [±SD] 5 ± 3%) of coronary artery disease. The SPECT protocol used separate acquisition of rest thallium-201 and adenosine Tc-99m sestamibi and was visually analyzed in 20 segments with a semiquantitative five-point scoring system (0 = normal; 4 = absent uptake).Results. The normaley rate in patients with a low likelihood of coronary artery disease was 93% (66 of 71). Among the catheterized group, the overall sensitivity, specificity and predictive accuracy of adenosine sestamibi SPECT for detecting coronary artery disease (⪰50% diameter stenosis) were 93% (87 of 94), 78% (28 of 36) and 88% (115 of 130), respectively. In the 103 patients without a prior myocardial infarction, the sensitivity, specificity and predictive accuracy were 91% (61 of 67), 78% (28 of 36) and 86% (89 of 103), respectively, for detecting ⪰50% diameter stenosis. Of particular interest, the sensitivity and specificity were as high in patients with nonanginal symptoms (93% and 69%, respectively) as in patients with angina (92% and 83%, respectively, p = NS). The sensitivity and specificity among patients with a relatively low (<25%), intermediate (between 25% and 75%) or high prescan likelihood of coronary artery disease (>75%) were similar: 82% and 82%, 93% and 73%, and 95% and 100%, respectively. The sensitivity and specificity for detecting individual diseased vessels (⪰50% diameter stenosis) were, respectively, 76% and 81% for the left anterior descending coronary artery, 44% and 90% for the left circumflex coronary artery and 75% and 77% for the right coronary artery.Conclusions. Adenosine Tc-99m sestamibi SPECT is an efficient protocol with high sensitivity and specificity for the detection of coronary artery disease in women irrespective of presenting symptoms or pretest likelihood of coronary artery disease and a high normaley rate. These findings are of particular clinical relevance because chest pain, anginal or otherwise, has been shown to be a frequent but a less specific marker for coronary artery disease among female patients.     

Technical aspects of myocardial SPECT imaging with technetium-99m sestamibi

Most reports to date using single photon emission computed tomography (SPECT) with technetium-99m (Tc-99m) sestamibi have used acquisition parameters that were optimized for thallium-201. To fully utilize the superior imaging characteristics of Tc-99m sestamibi, there is a need to optimize the technical aspects of SPECT imaging for this agent. Performance can be enhanced through the careful selection of optimal radiopharmaceutical doses, imaging sequences, acquisition parameters, reconstruction filters, perfusion quantification methods and multidimensional methods for visualizing perfusion distribution. The current report describes theoretical considerations, phantom studies and preliminary patient results that have led to optimized protocols, developed at Emory University and Cedars-Sinai Medical Center, for same-day rest-stress studies, given existing instrumentation and recommended dose limits. The optimizations were designed to fit a low-dose-high-dose rest-stress same-day imaging protocol. A principal change in the acquisition parameters compared with previous Tc-99m sestamibi protocols is the use of a high-resolution collimator. The approach is being developed in both prone and supine positions. A new method for extracting a 3-dimensional myocardial count distribution has been developed that uses spherical coordinates to sample the apical region and cylindrical coordinates to sample the rest of the myocardium. New methods for visualizing the myocardial distribution in multiple dimensions are also described, with improved 2-dimensional, as well as 3- and 4-dimensional (3 dimensions plus time) displays. In the improved 2-dimensional display, distance-weighted and volume-weighted polar maps are used that appear to significantly improve the representation of defect location and defect extent, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prognostic value of combined perfusion and function by stress technetium-99m sestamibi gated SPECT myocardial perfusion imaging in patients with suspected or known coronary artery disease

The incremental prognostic value of combined regional wall motion and perfusion over perfusion alone by gated single-photon emission computed tomographic myocardial perfusion scintigraphy has not been evaluated. Of the 402 consecutive patients who underwent stress single-photon emission computed tomographic myocardial perfusion scintigraphy for suspected myocardial ischemia, we identified 333 patients (217 men, mean age 63 +/- 10 years; exercise in 249 and dipyridamole adminstered to 84). Visual scoring of perfusion images and regional wall motion used 20 segments and a scale of 0 to 4. Resting and poststress left ventricular ejection fraction was automatically generated. On follow-up (median 13 months), 30 hard cardiac events (17 cardiac deaths, 13 nonfatal acute myocardial infarctions) and 66 total cardiac events (including hard events, 26 with unstable angina, and 10 who underwent late revascularization) occurred. After adjustment for prescan information, the best independent predictors of hard events were summed stress score for wall motion (Wald's chi-square 8.3, p <0.004) and several vascular territories with ischemia by perfusion/function (Wald's chi-square 6.2, p <0.01). The strongest predictors of all cardiac events were the number of ischemias (Wald's chi-square 32.1, p <0.0001) and the number of ischemic vascular territories by perfusion (Wald's chi-square 13.1, p <0.0001). Addition of function data to the combined model of perfusion data yielded an incremental value of 26% for predicting hard events but not for all events. In conclusion, the assessment of combined perfusion/function provides incremental prognostic information for further hard events with perfusion data alone; perfusion data best predict all cardiac events.     

Enhanced detection of reversible perfusion defects by Tc-99m sestamibi compared to Tc-99m tetrofosmin during vasodilator stress SPECT imaging in mild-to-moderate coronary artery disease

OBJECTIVES: We prospectively compared dipyridamole single-photon emission computed tomography (SPECT) imaging with Tc-99m sestamibi and Tc-99m tetrofosmin for the detection of reversible perfusion defects in patients with mild-to-moderate coronary artery disease. BACKGROUND: Tc-99m tetrofosmin has a lower first-pass myocardial extraction fraction compared to Tc-99m sestamibi and thus could underestimate mild perfusion defects. METHODS: Eighty-one patients with 50% to 90% stenosis in one or two major epicardial vessels without previous myocardial infarction, and seven with <5% probability of coronary artery disease underwent dipyridamole SPECT imaging with both agents. The SPECT data were analyzed quantitatively. RESULTS: Tc-99m sestamibi detected reversible perfusion defects in a greater number of segments (total 363 and 285, p < 0.001, and mean +/- SD, 2.2 +/- 3.0 and 1.8 +/- 2.5 per patient, p = 0.008, for Tc-99m sestamibi and Tc-99m tetrofosmin, respectively), demonstrated a larger extent of perfusion defect (mean +/- SD, 15.8% +/- 12.3% and 12.0% +/- 11.4%, p < 0.03, for Tc-99m sestamibi and Tc-99m tetrofosmin, respectively) and more often correctly identified patients with disease in more than one coronary artery (p = 0.02). There was better defect contrast with Tc-99m sestamibi (defect/normal wall count ratios were 0.60 +/- 0.15 vs. 0.73 +/- 0.14 for Tc-99m sestamibi and Tc99m tetrofosmin, respectively, p = 0.01, for reversible defects seen in identical segments with both agents; and 0.73 +/- 0.16 vs 0.79 +/- 0.17, respectively, p <0.01, for reversible defects detected with either agent alone). There was no significant difference in diagnostic sensitivity or image quality. CONCLUSIONS: These differences between two commonly used tracers may have significant diagnostic and prognostic implications.     

99mTc-MIBI心肌灌注断层显像在冠心病冠状动脉内支架置入术的应用

目的 :应用硝酸甘油 (NTG)介入 ,单光子发射计算机断层显像 (SPECT)检查估测冠状动脉 (冠脉 )介入治疗前后存活心肌的大小、范围。方法 :对 42例冠心病患者行静息及NTG介入SPECT心肌显像检查 ,应用阅片计分法、极坐标靶心图定量分析法估测心肌活力。以 19例接受经皮腔内冠脉成形术 (PTCA)加冠脉内支架置入 (Stent)术后静息显像结果为“金标准” ,评价NTG介入显像对心肌活力检测效果。结果 :静息显像及NTG介入SPECT显像其不规则感兴趣区内放射性稀疏缺损面积、放射性计数、放射性异常计分差异有显著性意义 (t分别为 7.5 43、4.6 0 8、6 .76 2 ,均 P <0 .0 0 1)。静息显像检测出存活心肌为 5 6 .3% ,NTG介入显像为 6 9.6 %。NTG介入显像估测存活心肌准确率为阅片计分法 80 .9% ,定量分析法 90 .5 %。结论 :NTG介入SPECT检查可提高存活心肌检出率 ,为冠脉内支架置入术治疗提供客观依据     

多巴酚丁胺负荷~(99m)Tc-MIBI心肌断层显像诊断冠心病的价值

56例多巴酚丁胺负荷~(99m)锝-甲氧基异丁基异腈(~(99m)Tc-MIBI)门控心肌灌注断层显像(DBA-SPECT),并进行多巴酚丁胺负荷心电图(DBA-ECG)及平板运动心电图.21例行冠脉造影.DBA负荷血液动力学效应曲线与平板运动试验之曲线相似.DBA-SPECT诊断冠心病的敏感性、特异性、准确率分别为87.5%、76.9%、81.0%;DBA-ECG诊断冠心病的敏感性、特异性、准确率分别为75.0%、92.3%、85.0%;平板运动心电图诊断冠心病的敏感性、特异性、准确率分别为87.5%、46.2%、61.9%.表明DBA-SPECT是诊断冠心病的一种具有较高敏感性和特异性的方法.且安全可靠,可部分代替运动负荷试验.     

Myocardial perfusion and angiographic findings in patients with paradoxical sinus deceleration during dobutamine technetium-99m sestamibi-gated SPECT imaging

AIMS: Dobutamine-gated SPECT imaging allows simultaneous perfusion and function assessment and is an alternative stress method for evaluating coronary artery disease in patients unable to perform treadmill exercise. In some patients, a paradoxical decrease in heart rate has been observed during high dose dobutamine infusion. The purpose of this study was to describe the paradoxical decrease in heart rate observed during dobutamine perfusion scintigraphy and determine its relation to inducible ischemia and angiographic coronary artery disease. METHODS AND RESULTS: We studied 52 patients who underwent dobutamine-gated (99m)Tc sestamibi SPECT imaging and coronary angiography within 30 days. Paradoxical deceleration was defined as a decrease in heart rate >/=5 beats/min lasting at least 3 min during dobutamine infusion. Perfusion was graded on a five-point scale (0 = normal; 4 = absent uptake) and wall motion on a four-point scale (0 = akinesia/dyskinesia; 3 = normal) using the 20-segment model. Significant coronary artery disease was defined as >/=50% narrowing of lumen diameter of a major epicardial artery. Paradoxical deceleration occurred in 10 patients (19%, 95% CI 8-30%). A decrease in systolic blood pressure [8 patients (80%), 95% CI 56-92%] with angina [5 patients (50%), 95% CI 23-71%] often accompanied the decrease in heart rate. All 10 patients with sinus deceleration had an inferior wall perfusion defect and 8 of them had a corresponding wall motion abnormality on gated images. Significant coronary artery disease was present in all 10 patients with sinus deceleration, with an increased incidence of right coronary artery stenosis (p = 0.007). CONCLUSIONS: Paradoxical deceleration observed during dobutamine perfusion scintigraphy is associated with inducible ischemia and angiographic coronary artery disease and the underlying mechanism for this phenomenon may be the activation of the Bezold-Jarisch reflex.     

Technical aspects of myocardial planar imaging with technetium-99m sestamibi

Fundamental quantitative planar imaging techniques, evolved over the years, have been adapted to maximize the efficiency and clinical effectiveness of technetium-99m (Tc-99m) sestamibi imaging. To ensure reproducible image interpretation, the Society for Motion Picture and Television Engineers test pattern is used to obtain the necessary standardization of video and hard copy images. A standardized intensity scale intuitively relates count density to perceived brightness. Data are accumulated via standard 16-frame multiple gated acquisition and can be viewed in cine mode to assess wall motion. The images are then automatically summed for quantitative analysis of myocardial perfusion. Excessive extracardiac Tc-99m activity is automatically suppressed by the computer program to prevent suboptimal display of the heart. Due to the difference in heart background ratio and shape of the extracardiac background between resting and exercise Tc-99m sestamibi images, a modified interpolative background subtraction algorithm was developed. Image registration is necessary for accurate comparison of the rest and exercise images to detect redistribution. This is automatically accomplished by adjusting the position of the background-subtracted and centered images so as to maximize the cross-correlation coefficient. Profiles are generated to sample the myocardial count distribution and can be compared to a normal database, subject to confirmation by a competent interpreter. Rest redistribution is defined by a change in the myocardial distribution of Tc-99m sestamibi between exercise and rest images. Flashback display is used to identify subtle regions of redistribution that often signify residual viability within an infarct zone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Myocardial perfusion imaging in coronary artery disease

Radionuclide myocardial perfusion imaging (MPI) can be used to demonstrate the presence of coronary heart disease and to risk stratify and guide management of patients with known disease. It has the ability to localize hemodynamically important coronary stenoses, and assess the extent and severity of coronary obstruction by the presence and extent of perfusion defects. A normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease. Cardiac PET has the advantage from SPECT of higher spatial and temporal resolution, and a decreased radiation exposure to patients. Hybrid cardiac imaging combining SPECT or PET with CT data appears to offer superior diagnostic and prognostic information in patients with intermediate risk for CAD. A significant progress in better quantification of myocardial blood flow and coronary flow reserve has recently been seen. Also several studies have demonstrated that the combination of imaging apoptosis and matrix metalloproteinases production can help imaging vulnerable plaque and identifying the group of high-risk asymptomatic patients who will benefit most by an imaging procedure.     

Myocardial perfusion imaging with technetium-99m-labeled agents.

Thallium-201 (201Tl) is suboptimal as a single-photon emitting agent for myocardial perfusion imaging, in view of its low-energy photons and long half-life. To circumvent these limitations, two new myocardial perfusion imaging agents labeled with technetium-99m (99mTc) have been developed. They are Tc-sestamibi and Tc-teboroxime. Clinical trials of myocardial perfusion with both tracers have shown results similar to those obtained with 201Tl for detection of coronary artery disease. Results to date indicate that Tc-sestamibi accurately detects and locates myocardial infarction and can accurately assess both left and right ventricular ejection fractions by the first-pass technique. In addition, research has shown that rest-stress studies can be performed on the same day and that Tc-sestamibi can be used to assess the results of thrombolytic therapy. Tc-teboroxime has excellent myocardial tracer uptake characteristics but is cleared very rapidly from the myocardium. These features make Tc-teboroxime well suited to rapid serial studies. These new technetium myocardial perfusion agents have just become available for routine clinical use and are likely to replace 201Tl in many of its clinical applications.     

Comparison of single-photon emission computed tomographic (SPECT) myocardial perfusion imaging with thallium-201 and technetium-99m sestamibi in dogs.

OBJECTIVES. The purpose of the present study was to compare single-photon emission computed tomographic (SPECT) myocardial images of technetium-99m (Tc-99m) sestamibi and thallium-201 (Tl-201) isotopes in the same dog undergoing partial coronary occlusion during pharmacologic vasodilation. BACKGROUND. To date, no controlled study has been reported comparing SPECT Tc-99m sestamibi with SPECT Tl-201 imaging during stress with anatomic and physiologic standards. METHODS. Mongrel dogs were anesthetized with chloralose and instrumented to record left anterior descending coronary blood flow and aortic pressure. Partial coronary occlusion with a hydraulic cuff reduced coronary vascular conductance, which is equal to the coronary blood flow normalized to aortic pressure during peak vasodilation with intravenous adenosine. Each dog received 5 mCi of Tl-201, then 30 mCi of Tc-99m sestamibi during partial coronary occlusion at peak vasodilation. Tomographic myocardial imaging was performed in a 180 degrees anterior arc scan for 33.5 min, first with Tl-201, and later, without moving the dog, for 33.5 min with Tc-99m sestamibi. Postmortem staining defined the region underperfused because of its dependence on the artery that was partially occluded. RESULTS. In seven dogs with moderate reduction in coronary blood flow, coronary vascular conductance decreased with partial coronary occlusion (47 +/- 12%) during Tl-201 imaging and (47 +/- 8%, p = NS) during Tc-99m sestamibi imaging. The underperfused region was 23.9 +/- 6.4% of total left ventricular mass. Counts in the defects were 39% higher (0.86 +/- 0.08 of normal counts) for Tc-99m sestamibi than for Tl-201 (0.64 +/- 0.09 of normal counts, p < 0.001), and the defect on SPECT Tc-99m sestamibi images occupied only a fraction (0.37 +/- 0.30) of the area of the defect on the Tl-201 images of the same dog. Bull's-eye displays constructed from the pathologic slices showed that the Tl-201 defect size was closer to the underperfused region of the left ventricular mass determined pathologically than was the Tc-99m sestamibi defect size. In four additional dogs a severe, near total coronary occlusion was created during Tl-201 and Tc-99m sestamibi administration. In these dogs, similar defect contrast (0.55 +/- 0.12 vs. 0.62 +/- 0.09, p = NS) and areas (0.18 +/- 0.07 vs. 0.18 +/- 0.11, p = NS) were observed with Tl-201 and Tc-99m sestamibi, respectively. CONCLUSIONS. Tomographic myocardial imaging with Tc-99m sestamibi during moderately severe partial coronary occlusion underestimated the area of the defect relative to Tl-201 or to the pathologic reference standard in dogs. Defect contrast was sharper with tomographic myocardial Tl-201 than with tomographic myocardial Tc-99m sestamibi during moderately severe partial coronary occlusion.     

Simultaneous measurement of myocardial perfusion and ventricular function during exercise from a single injection of technetium-99m sestamibi in coronary artery disease

New radiopharmaceuticals permit simultaneous assessment of myocardial perfusion and left ventricular function using a single tracer injection. The purpose of this study was to quantitate the relation between myocardial perfusion and function at rest and during exercise in patients with documented coronary artery disease (CAD). A rest first-pass radionuclide angiocardiogram (RNA) was recorded in 51 patients with CAD during injection of 10 mCi of technetium-99m (Tc-99m) sestamibi, and tomographic perfusion images were obtained 60 minutes later. A treadmill test was then performed, and on attainment of an exercise end point a second first-pass RNA was recorded with 30 mCi of Tc-99m sestamibi. Tomographic images reflecting myocardial perfusion during exercise were obtained 1 hour later. Tomographic perfusion defect size, quantified using modifications of the Cedars-Sinai program, correlated directly with end-systolic volume and inversely with ejection fraction at rest and during exercise. However, perfusion defect size often varied widely in patients with similar left ventricular function. This independence between measurements of perfusion and function suggests that simultaneous assessment of the 2 physiologic variables could improve the diagnostic and prognostic information of radionuclide tests.     

Prognostic significance of fixed perfusion abnormalities on stress technetium-99m sestamibi single-photon emission computed tomography in patients without known coronary artery disease

Fixed perfusion abnormalities in patients with known coronary artery disease (CAD) are associated with myocardial damage and adverse outcomes. However, the significance of these abnormalities in patients without known CAD is unclear. The aim of this study was to assess the prognostic significance of fixed versus reversible perfusion abnormalities in patients without known CAD. We studied 327 patients (58 +/- 11 years of age; 215 men) with no history of myocardial infarction or revascularization, who demonstrated myocardial perfusion abnormalities on stress (exercise or dobutamine) sestamibi tomographic imaging. Follow-up end points were all-cause mortality and hard cardiac events (cardiac death and nonfatal myocardial infarction). Myocardial perfusion abnormalities were reversible in 226 patients (69%) and fixed in 101 patients (31%). During a mean follow-up of 7 years, 72 patients (22%) died (cardiac death in 30) and 15 patients had nonfatal myocardial infarctions. The annual mortality rate was higher in patients with fixed abnormalities than in those with reversible abnormalities (4.4% vs 2.7%, p <0.01), whereas the annual hard cardiac event rate was not significantly different between the 2 groups (2.5% vs 2%). In a multivariate analysis model, the summed stress score was an independent predictor of hard cardiac events (risk ratio 1.7, 95% confidence interval 1.3 to 5.4). The presence of a fixed perfusion abnormality was independently associated with an increased risk of death after adjustment for clinical and stress test data and the summed stress score (risk ratio 2.5, 95% confidence interval 1.3 to 3.7). In patients with suspected, but no history of CAD, fixed perfusion abnormalities were associated with a higher risk of death compared with reversible perfusion abnormalities.     

Assessment of myocardial perfusion and contractile function by inotropic stress Tc-99m sestamibi SPECT imaging and echocardiography for optimal detection of multivessel coronary artery disease

Objective—To assess whether inotropic stress myocardial perfusion imaging, echocardiography, or a combination of the two could enhance the detection of multivessel disease, over and above clinical and exercise electrocardiographic data.
Design—100 consecutive patients investigated by exercise electrocardiography and diagnostic coronary arteriography underwent simultaneous inotropic stress Tc-99m sestamibi SPECT (MIBI) imaging and echocardiography. MIBI imaging and echocardiographic data were analysed using a 12 segment left ventricular model, and each segment was ascribed to a particular coronary artery territory. The presence of perfusion defects with MIBI imaging or of wall thickening abnormality with echocardiography in at least two coronary artery territories at peak stress was taken as diagnostic of multivessel disease. Arteriographic evidence of  50% stenosis was considered significant.
Results—56 patients had multivessel disease. The sensitivity of the combination of MIBI imaging and echocardiography for detecting this was greater than either MIBI imaging or echocardiography alone (82%, 68%, and 68%, respectively; p = 0.005). Clinical and exercise electrocardiographic variables gave an R² value of 18.2% for predicting multivessel disease. The addition of either MIBI imaging (R² = 29.2%; p = 0.002) or echocardiography (R² = 28.8%; p < 0.001) enhanced the detection of multivessel disease, and the inclusion of both had further incremental value (R² = 34.8%; p = 0.003). Age (p = 0.03), MIBI imaging (p = 0.007), and echocardiography (p = 0.001) were independent predictors of multivessel disease.
Conclusions—The assessment of both myocardial perfusion and contractile function by simultaneous inotropic stress MIBI imaging and echocardiography optimises the non-invasive detection of multivessel disease.

Keywords: multivessel disease;  inotropic stress;  SPECT imaging;  echocardiography     

Gated technetium-99m methoxy-isobutylisonitrile perfusion imaging.

Technetium-99m methoxy-isobutylisonitrile, has been shown to be a useful perfusion agent for detecting coronary artery disease. Gated acquisition of perfusion images may remove motion artefact and improve detection. We compared the results of sensitivity and specificity for detecting coronary artery disease using perfusion images from the whole cardiac cycle (ungated) or from end-diastolic (gated) frames in 46 subjects, 31 with significant coronary disease and 15 with normal coronary arteries. There was no significant difference in detection of patients with coronary disease between the ungated and end-diastolic images: 25/31 with the ungated image and 28/31 with the end-diastolic. An improvement was made in detecting defects in the left anterior descending artery territory: 17/20 with the end-diastolic vs 11/20 with the ungated image (P less than 0.05) and in the right coronary artery region: 16/21 vs 10/21 (P less than 0.05), with an overall improvement in detecting regions supplied by stenosed coronary arteries: 45/55 end-diastolic vs 31/55 ungated (P less than 0.01). These results suggest use of the end-diastolic frame can significantly enhance the diagnostic capacity of methoxy-isobutylisonitrile perfusion imaging.     

Clinical correlation between increased lung to heart ratio of technetium-99m sestamibi and multivessel coronary artery disease

BACKGROUND: An increased lung to heart ratio (LHR) on thallium-201 (Tl-201) stress myocardial perfusion imaging (MPI) is a predictor of adverse cardiac events and identifies people with extensive coronary artery disease (CAD). The implications of increased LHR in patients undergoing stress technetium-99m (tc-99m) sestamibi are developing. Our aim is to evaluate the relationship between increased LHR and extent of CAD in patients undergoing tc-99m sestamibi MPI. METHODS: We reviewed the records and images of 530 consecutive subjects who underwent exercise or adenosine tc-99 m sestamibi MPI. One hundred thirty-two had transient or partially reversible myocardial perfusion defects and 79 (exercise=34, adenosine=45, male=43, female=36, mean age=61 years) of these underwent coronary angiography (study population). The average LHR of these 79 subjects was compared to 79 patients (control population) with normal scans (exercise=50, adenosine=29, male=34, female=45, mean age=60 years). RESULTS: The mean LHR (+/-SE) in subjects with normal scans was 0.30+/-0.01. The mean LHR for those with abnormal scans and single vessel CAD who underwent exercise was 0.32+/-0.01 and pharmacological stress was 0.31+/-0.01. There was no statistically significant difference between the LHR of those with a normal scan and those with single vessel disease and an abnormal scan. However, there was a statistically significant association between the elevated LHR and multi-vessel CAD. The mean LHR for subjects with multi-vessel CAD with exercise was 0.39+/-0.01 (p=0.000) and for adenosine was 0.39+/-0.02 (p=0.000). CONCLUSION: An elevated LHR in patients undergoing exercise or pharmacological tc-99m MPI correlates with multi-vessel CAD.     

Detection and assessment of unstable angina using myocardial perfusion imaging: comparison between technetium-99m sestamibi SPECT and 12-lead electrocardiogram

Forty-five studies using technetium-99m (Tc-99m) sestamibi single photon emission computed tomography (SPECT) were performed on patients hospitalized for spontaneous chest pain suggestive of myocardial ischemia. The studies were done after an injection during an episode of chest pain and a repeated injection when the patients were free of pain. All patients were hospitalized with a presumed diagnosis of unstable angina, and none had evidence of a previous myocardial infarction. The presence of a perfusion defect observed with Tc-99m sestamibi injected during chest pain had a 96% sensitivity and a 79% specificity for the detection of significant coronary artery disease (stenosis greater than or equal to 50%) on subsequent angiography. When the criterion of a larger perfusion defect during pain compared to absence of pain was used, the sensitivity was 81% and the specificity was 84%. In contrast, transient electrocardiographic ischemic changes during pain had a sensitivity of 35% and a specificity of 68%; electrocardiographic changes during or outside episodes of chest pain had a sensitivity of 65% and a specificity of 63% for the diagnosis. Tc-99m sestamibi SPECT represents a reliable noninvasive diagnostic tool that could aid in the diagnosis of myocardial ischemia in patients with spontaneous chest pain and provide additional information to that provided by the electrocardiogram.     

Prediction of all-cause mortality in women with known or suspected coronary artery disease by stress technetium-99m tetrofosmin myocardial perfusion imaging

We studied the incremental value of stress technetium-99m tetrofosmin imaging for predicting all-cause mortality in 503 women (aged 58 +/- 12 years) with known or suspected coronary artery disease. The annual mortality rate was 1.4% with normal perfusion and 4% with abnormal perfusion (p <0.01) during a follow-up of 3.5 +/- 1.2 years. In an incremental multivariate analysis model, clinical predictors of mortality were age, diabetes mellitus, smoking, and a lower systolic blood pressure during stress. An abnormal scan was incremental to clinical data in predicting mortality.