Thallium-201 single-photon emission computed tomography (SPECT) in the assessment of coronary artery disease.

Of all currently available techniques, thallium-201 single-photon emission computed tomography (SPECT) is the most time-tested noninvasive method for the detection of coronary artery disease (CAD). Recent pooled data show an overall sensitivity of 90% and a specificity of 70% for thallium-201 SPECT. Of patients with single-vessel coronary disease, 83% are identified by SPECT. Nearly all patients with double- and triple-vessel coronary disease (93% and 95%, respectively) are also identified. Thallium-201 SPECT imaging is also very effective in diagnosing CAD imaging is also very effective in diagnosing CAD using pharmacologic stress testing. In certain patient populations (e.g., in sedentary patients or those using anti-ischemic medications), pharmacologic stress testing with dipyridamole or adenosine may be a logical alternative to exercise testing. Moreover, many patients have physical disabilities that preclude appropriate exercise testing. Intravenous adenosine is a very potent direct coronary vasodilator, with the advantage of an ultrashort half-life, which eliminates the need to administer an antagonist in the majority of patients. In addition, the dosage of adenosine can be adjusted during the infusion, if necessary. The importance of thallium-201 SPECT during exercise or pharmacologic vasodilation transcends diagnosis, since it also plays an important role in the prognostic evaluation of patients with stable angina or postmyocardial infarction. Risk evaluation can be done with submaximal exercise electrocardiographic testing, but there is evidence that the addition of perfusion scintigraphy enhances the ability to predict future risk.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stress scintigraphy using single-photon emission computed tomography in the evaluation of coronary artery disease

Twenty-seven patients with angina pectoris, 24 with postmyocardial infarction angina and 7 with normal coronary arteries were examined by exercise thallium-201 emission computed tomography (SPECT) and planar scintigraphy. Exercise SPECT was compared with the reperfusion imaging obtained approximately 2 to 3 hours after exercise. The sensitivity and specificity of demonstrating involved coronary arteries by identifying the locations of myocardial perfusion defects were 96 and 87% for right coronary artery, 88 and 89% for left anterior descending artery (LAD) and 78 and 100% for left circumflex artery (LC). These figures are higher than those for planar scintigraphy (85 and 87% for right coronary artery, 73 and 89% for LAD and 39 and 100% for LC arteries). In patients with 3-vessel disease, sensitivity of SPECT (100, 88 and 75% for right coronary artery, LAD and LC, respectively) was higher than planar imaging (88, 63 and 31%, respectively), with a significant difference for LC (p less than 0.05). In 1, 2 and 0-vessel disease the sensitivity and specificity of the 2 techniques were comparable. Multivessel disease was more easily identified as multiple coronary involvement than planar imaging with a significant difference in 3-vessel disease (p less than 0.05). In conclusion, stress SPECT provides useful information for the identification of LC lesions in coronary heart disease, including 3-vessel involvement.     

Culprit lesion and jeopardized myocardium: Correlation between coronary angiography and single-photon emission computed tomography

Background: The term “culprit lesion” is used to designate the coronary stenosis responsible for the symptoms of the patient with coronary artery disease. Its detection is essential when partial revascularization is contemplated. The term “jeopardized myocardium” is commonly used to mean the amount of myocardium put in danger by all the stenotic lesions; however, it should be restricted to the amount of myocardium that could become infarcted if only the most severe stenoses were occluded. Hypothesis: The aim of this study was to investigate (1) the agreement between coronary myocardial single-photon emission computed tomography (SPECT) and coronary angiography for the identification of the culprit lesion, and (2) the correlation of the two studies in the quantification of jeopardized myocardium. Methods: In all, 159 patients with coronary artery disease without previous myocardial infarction were included in the study. A score for myocardial SPECT was correlated with the angiographic scores by Califf and Gensini and with the authors' score which includes adjustment for collateral circulation. Results: The agreement between coronary angiography and SPECT for the diagnosis of the culprit lesion was 84% (87/104). The correlations between the scores of angiography and SPECT to assess jeopardized myocardium when all coronary stenoses were taken into account were significant (p<0.0001), but their coefficients were suboptimal (r = 0.48 for Califf, r = 0.48 for Gensini, and r = 0.65 for the authors' score). When only the jeopardized myocardium resulting from the culprit lesion was considered, the correlation clearly improved (r=0.85). Conclusion: Thus, in 84% of patients with multivessel disease, an agreement between coronary angiography and myocardial SPECT for the diagnosis of the culprit lesion was observed. The correlation between these techniques for the quantification of jeopardized myocardium from the culprit lesion was satisfactory.     

Standard versus user-interactive assessment of significant coronary stenoses with multislice computed tomography coronary angiography

Forty-four patients in sinus rhythm with suspected coronary artery disease underwent 16-row multislice computed tomography coronary angiography and conventional coronary angiography. Two protocols for image analysis were applied to the multislice computed tomographic images: standard projections versus interactive postprocessing. The diagnostic accuracy of both methods for the detection of significant lesions (>50% lumen reduction) was compared with quantitative coronary angiography. Sensitivity and specificity were 58% and 96% and 96% and 97%, for standard projections and interactive postprocessing protocol, respectively.     

Diagnostic performance of 64-slice computed tomography coronary angiography to detect significant coronary artery stenosis

OBJECTIVE: We aimed to determine the diagnostic accuracy of 64-slice multi-slice computed tomography (MSCT) to detect significant coronary artery stenosis with comparison to conventional coronary angiography (CCA). METHODS: In 100 patients (70 men, average age 58 +/- 10 years and age range 31-75 years) scheduled to have conventional coronary angiography, MSCT was performed before catheterization (within 2 months). All patients were in sinus rhythm, able to hold breath for 15 seconds, and had serum creatinine levels < 1.5 mg/dl. MSCT scans were analysed by a radiologist and a cardiologist. Sensitivity, specificity, positive and negative predictive values for the detection of significant stenoses by MSCT in comparison with CCA were calculated on patient, vessel, and segmental bases. RESULTS: 64-slice computed tomography is able to detect significant coronary artery stenosis on a segmental basis with a sensitivity of 88% and specificity of 99% when compared with CCA. All patients with significantly stenotic coronary artery disease are correctly diagnosed. The presence of significant stenosis was correctly diagnosed by MSCT in 126 of 144 segments. Twelve non-significant lesions on CCA were overestimated by MSCT. On vessel-based analysis, the sensitivity and specificity of MSCT for detecting significant stenosis were 91% and 97%, respectively. CONCLUSION: Our results indicate that 64-slice computed coronary angiography is a reliable diagnostic modality for the detection of significant coronary artery stenosis in patients with sinus rhythm and scheduled to have CCA, but still has limitations of diagnostic performance on a per-segment and per-vessel basis.     

Comparison of planar imaging and single-photon emission computed tomography for the detection and localization of coronary artery disease

Although single photon emission computed tomography (SPECT) has become widely utilized, the superiority of this technique compared to planar conventional imaging remains controversial. In order to compare these two techniques, we retrospectively analysed the results obtained in 70 patients who performed a thallium-201 exercise scintigraphy with a double acquisition during the same test, and who also underwent coronary and ventricular angiography. Overall, SPECT imaging yielded a higher sensitivity (93% vs 82% for SPECT and planar imaging respectively, p<0.05), especially in the inferior and anterior regions. SPECT was also more sensitive for the detection of a single-vessel disease (90% vs 74% for SPECT and planar imaging respectively, p<0.01). The specificity was assessed for both techniques with the help of circumferential computerized analysis, avoiding known causes of false positive scintigrams. We found a high specificity for both SPECT and planar imaging, without any significant difference between the two methods (87% vs 91% for the overall specificity of SPECT and planar imaging respectively, p=NS). Therefore, SPECT imaging analysed with discrimination shows an enhanced reliability over planar imaging for the detection and the localization of coronary artery disease, without increasing the risk of false positive tests.     

Pre-operative computed tomography coronary angiography to detect significant coronary artery disease in patients referred for cardiac valve surgery.

OBJECTIVES: We studied the diagnostic performance of 64-slice computed tomography coronary angiography (CTCA) to rule out or detect significant coronary stenosis in patients referred for valve surgery. BACKGROUND: Invasive conventional coronary angiography (CCA) is recommended in most patients scheduled for valve surgery. METHODS: During a 6-month period, 145 patients were prospectively identified from a consecutive patient population scheduled for valve surgery. Thirty-five patients were excluded because of CTCA criteria: irregular heart rhythm (n = 26), impaired renal function (n = 5), and known contrast allergy (n = 4). General exclusion criteria were: hospitalization in community hospital (n = 4), no need for CCA (n = 4), previous coronary artery bypass surgery (n = 1), or percutaneous coronary intervention (n = 4). Of the remaining 97 patients, 27 denied written informed consent. Thus, the study population comprised 70 patients (49 male, 21 female; mean age 63 +/- 11 years). RESULTS: Prevalence of significant coronary artery disease, defined as having at least 1 > or =50% stenosis per patient, was 25.7%. Beta-blockers were administered in 71%, and 64% received lorazepam. The mean heart rate dropped from 72.5 +/- 12.4 to 59.5 +/- 7.5 beats/min. The mean scan time was 12.8 +/- 1.3 s. On a per-patient analysis, the sensitivity, specificity, and positive and negative predictive values were: 100% (18 of 18; 95% confidence interval [CI] 78 to 100), 92% (48 of 52; 95% CI 81 to 98), 82% (18 of 22; 95% CI 59 to 94), and 100% (48 of 48; 95% CI 91 to 100), respectively. CONCLUSIONS: The diagnostic accuracy of 64-slice CTCA for ruling out the presence of significant coronary stenoses in patients undergoing valve surgery is excellent and allows CTCA implementation as a gatekeeper for invasive CCA in these patients.     

Beneficial effect of coronary artery bypass grafting as assessed by quantitative gated single-photon emission computed tomography.

The development of quantitative gated single-photon emission computed tomography (SPECT) has enabled the assessment of left ventricular perfusion, function and wall thickness in a single examination. Accordingly, the present study used gated SPECT to assess the benefit of coronary artery bypass grafting (CABG) in patients with coronary artery disease; 47 of those patients were evaluated before and 5 months after CABG. As a result of coronary revascularization, a significant improvement was observed in global ejection fraction (50+/-12 --> 53+/-11%; p<0.05). In 107 revascularized territories, the average regional reversible defect score (0.8+/-0.5 --> 0.2 +/-0.3; p<0.0001), average regional perfusion score at rest (0.6+/-0.6 --> 0.3+/-0.4; p<0.0001), average regional wall motion score (0.9+/-0.7 --> 0.7+/-0.5; p<0.05), and end-diastolic wall thickness (8.1+/-1.3 --> 8.6+/-1.5 mm; p<0.0005) all improved significantly. Even in 34 non-revascularized territories, the average regional reversible defect score (0.5+/-0.7 --> 0.2+/-0.5; p<0.03), average regional wall motion score (0.8+/-1.1 --> 0.5 +/-1.0; p<0.03) and end-diastolic wall thickness (8.0+/-1.4 --> 9.1+/-2.0 mm; p<0.03) all improved significantly. These results indicate that improvement in myocardial ischemia, hibernation and left ventricular function with CABG can be assessed in detail with gated SPECT.     

Assessment of coronary artery disease using single-photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia

Thallium-201 myocardial imaging during dipyridamole-induced coronary hyperemia has been an accepted method for diagnosing coronary artery disease (CAD) and risk stratification. Adenosine is a powerful short-acting coronary vasodilator. Initial results of thallium imaging during adenosine infusion have been encouraging. In 132 patients with CAD and in 16 patients with normal coronary angiograms, adenosine was given intravenously at a dose of 0.14 mg/kg/min for 6 minutes and thallium-201 was injected at 3 minutes. The thallium images using single-photon emission computed tomography were abnormal in 47 of the 54 patients (87%) with 1-vessel, in 34 of 37 patients (92%) with 2-vessel and in 40 of 41 patients (98%) with 3-vessel CAD. The sensitivity was 92% in the 132 patients with CAD (95% confidence intervals, 86 to 96%). In patients with normal coronary angiograms, 14 of 16 patients had normal thallium images (specificity, 88%; 95% confidence intervals, 59 to 100%). The results were very similar when subgroups of patients were analyzed: those without prior myocardial infarction, elderly patients and women. The nature of the perfusion defects (fixed or reversible) was assessed in relation to whether the 4-hour delayed images were obtained with or without the reinjection technique. In patients who underwent conventional delayed imaging, there were more fixed perfusion defects than in patients with reinjection delayed imaging (16 vs 0%, p less than 0.0001). The adverse effects were mild, transient and well tolerated. Thus, adenosine thallium tomographic imaging provides a high degree of accuracy in the diagnosis of CAD. The use of the reinjection technique enhances the ability to detect reversible defects.     

Relationship between exercise echocardiography and perfusion single-photon emission computed tomography in patients with single-vessel coronary artery disease.

The aim of this study was to assess the relative value of exercise echocardiography and perfusion single-photon emission computed tomography (SPECT) in identifying the presence and severity of coronary artery stenosis. Accordingly, 44 consecutive patients with stenosis in one vessel performed simultaneous postexercise echocardiography and perfusion SPECT (with either thallium-201 [n = 19] or 99m-Tc-methoxyisobutyl isonitrile [n = 25]) in conjunction with symptom-limited bicycle exercise testing. Positive test results were based on the presence of new or worsened exercise-induced wall motion abnormalities and transient perfusion defects, respectively. Moreover, an "ischemic" score index was derived for semiquantitative assessment of both echocardiography (with a 14-segment model of left ventricular wall on a 4-point scale) and SPECT (47-segment model on a 5-point scale). All patients underwent correlative coronary arteriography, assessed by digital caliper. Significant coronary artery disease (diameter stenosis greater than or equal to 50%) was present in 30 patients. There was a good overall concordance between the two tests in terms of result (79%); compared with patients with positive results of both tests, in the seven patients with positive SPECT and negative echocardiography the time of recording echocardiographic images was longer (p = 0.05). When analyzing patients according to the percent diameter stenosis (greater than 70%, 50% to 70%, and less than 50%) for both echocardiography and SPECT, the prevalence of an ischemic response was directly related to the severity of the coronary stenosis (p less than 0.001); moreover, a negative test result was highly predictive of a diameter coronary stenosis less than 70%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary computed tomography angiography in coronary artery disease

AIM: To investigate the research directions of coronary computed tomography (CT) angiography in the diagnosis of coronary artery disease (CAD) based on a systematic review of the literature.METHODS: A search of articles on coronary CT angiography in the diagnosis of CAD was performed during a 6-year-period between 2005 and 2010 from f ive main radiology journals namely, Radiology, American Journal of Roentgenology, European Radiology, European Journal of Radiology and British Journal of Radiology. Analysis of the references was focused on the research directions of coronary CT angiography with regard to the type of studies in terms of diagnostic value, application of dose-reduction strategies and resultant effective radiation doses with use of these techniques.RESULTS: One hundred and forty two studies were identified which met the selection criteria and were included in the analysis. 64-slice CT (single source anddual-source CT) dominated 78% of the coronary CT angiography studies. Prior to 2007, research was focused on the diagnostic value of coronary CT angiography, but since 2008 more attention has been paid to radiation dose reduction. Radiation dose was reported in 64 studies, representing 45% of total studies published in the f ive radiology journals. Various dose-saving strategies have been implemented and prospective electrocardiography-triggering and high pitch techniques were found to be the most effective approaches for radiation dose reduction, with the corresponding mean effective dose being 3.5 ± 1.9 mSv and 1.7 ± 0.6 mSv, respectively.CONCLUSION: This review shows that the current research in coronary CT angiography has shifted from the previous focus on diagnostic accuracy in CAD to more emphasis on radiation dose reduction.     

Quantitative thallium-201 single-photon emission computed tomography during maximal pharmacologic coronary vasodilation with adenosine for assessing coronary artery disease

The diagnostic value of maximal pharmacologic coronary vasodilation with intravenously administered adenosine in conjunction with thallium-201 single-photon emission computed tomography (SPECT) for detection of coronary artery disease was investigated in 101 consecutive patients who had concomitant coronary arteriography. Tomographic images were assessed visually and from computer-quantified polar maps of the thallium-201 distribution. Significant coronary artery disease, defined as greater than 50% luminal diameter stenosis, was present in 70 patients. The sensitivity for detecting patients with coronary artery disease using quantitative analysis was 87% in the total group, 82% in patients without myocardial infarction and 96% in those with prior myocardial infarction; the specificity was 90%. The sensitivity for diagnosing coronary artery disease in patients without infarction with single-, double-and triple-vessel disease was 76%, 86% and 90%, respectively. All individual stenoses were identified in 68% of patients with double-vessel disease and in 65% of those with triple-vessel disease. The extent of the perfusion defects, as quantified by polar maps, was directly related to the extent of coronary artery disease. In conclusion, quantitative thallium-201 SPECT during adenosine infusion has high sensitivity and specificity for diagnosing the presence of coronary artery disease, localizing the anatomic site of coronary stenosis and identifying the majority of affected vascular regions in patients with multivessel involvement.     

64层CT冠状动脉成像技术和冠状动脉造影对冠状动脉疾病诊断的对照研究

目的比较64层计算机断层摄影扫描冠状动脉成像技术(64-slice computed tomography coronaryangiography,64-SCTCA)和冠状动脉造影(coronary artery angiography,CAG)在冠状动脉粥样硬化性心脏病(冠心病)诊断中的价值。方法回顾性分析126例疑似冠心病的患者64-SCTCA和CAG检查资料,并对两组资料进行对比分析。结果 64-SCTCA和CAG检查结果中可用于评价的病变血管段支数比较,差异无统计学意义(P0.05)。CAG共发现≥50%狭窄节段242个,64-SCTCA共发现≥50%狭窄节段199个,两种检查方法对病变狭窄的显示情况比较,差异无统计学意义(P0.05)。全部126例冠心病患者中有91%通过64-SCTCA发现(110/121)。64-SCTCA诊断冠状动脉病变血管的敏感性、特异性、阳性预测值、阴性预测值分别为81.6%、98.8%、79.5%、99%。结论 64-SCTCA可作为冠心病无创、便捷、可靠的检查方法。     

Usefulness of single-photon emission computed tomography of thallium-201 uptake after dipyridamole infusion for detection of coronary artery disease.

The diagnostic performance of single-photon emission computed tomography (SPECT) and planar imaging of thallium-201 uptake for the detection of coronary artery disease (CAD) was compared in 79 patients who underwent both dipyridamole thallium-201 scintigraphy and coronary angiography. Clinical subgroups were assigned by severity of CAD, presence of a prior myocardial infarction and the number of narrowed coronary arteries. The overall detection of CAD was 89% for SPECT and 67% for planar (p less than 0.001). For the anterior vascular territory, sensitivities for SPECT and planar imaging were 69 and 44% (p less than 0.01), respectively; for the posterior vascular territory, sensitivities were 80 and 54% (p less than 0.01). Receiver-operating characteristic analysis, using a 5-point evaluation scale, was performed for the anterior and posterior vascular territories. Receiver-operating characteristic curves generated for SPECT and planar studies demonstrated improved diagnostic performance by SPECT in the anterior vascular territory, but showed similar performance in the posterior territory because of lower SPECT specificity despite higher sensitivity at clinically relevant decision thresholds. In each clinical subgroup of patients, the detection of CAD by SPECT was significantly superior to that by planar imaging, regardless of the severity of stenosis or the number of significantly narrowed coronary arteries, or whether a myocardial infarction was present. Thus, SPECT thallium-201 scintigraphy is an important and necessary clinical tool for detecting CAD after dipyridamole infusion.     

Exercise echocardiography and technetium-99m MIBI single-photon emission computed tomography in the detection of coronary artery disease

To compare the relative diagnostic value of exercise echocardiography with perfusion technetium-99m metoxyisobutylisonitrile single-photon emission computed tomography (SPECT) in detecting coronary artery disease (CAD), 75 patients with suspected CAD but a normal electrocardiogram (ECG) at rest were included in a prospective correlative study. Both the exercise echocardiograms and SPECT studies were performed in conjunction with the same symptom-limited bicycle exercise test. The development of either a new wall motion abnormality or a reversible perfusion defect after exercise, or both, were regarded as a positive test for the exercise echocardiographic and SPECT studies, respectively. The results of these 2 diagnostic tests were compared with coronary arteriography. Exercise echocardiography identified 35 (71%) and SPECT 41 (84%, p = 0.13) of the 49 patients with significant CAD (defined as greater than 50% diameter stenosis). Twenty-five of the 26 patients (96%) without significant coronary stenosis had negative exercise echocardiographic results and 23 of 26 (88%) had negative SPECT results. Exercise-induced new wall motion abnormalities showed a good correlation with reversible perfusion defects, and the results of the 2 methods were concordant in 65 of 75 patients (agreement = 88%, kappa = 0.75 +/- 0.14). Both the diagnostic accuracy of exercise echocardiography and SPECT were significantly higher than the exercise ECG (81 vs 64%, p less than 0.02 and 88 vs 64%, p less than 0.005). The sensitivity and specificity for detecting individual diseased vessels were 60 and 95% for exercise echocardiography and 67 and 94% for SPECT.(ABSTRACT TRUNCATED AT 250 WORDS)