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EMUNI, FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Objectives. The purpose of this study was to determine the prognostic value of automatic quantitative analysis in exercise dual-isotope myocardial perfusion single-photon emission computed tomography ...(SPECT) and to compare the prognostic value of quantitative analysis to semiquantitative visual SPECT analysis.
Background. Extent, severity and reversibility of exercise myocardial perfusion defects have been shown to correlate with prognosis. However, most studies examining the prognostic value of SPECT in chronic coronary artery disease (CAD) have been based on visual analysis by experts.
Methods. We studied 1,043 consecutive patients with known or suspected CAD who underwent rest Tl-201/exercise Tc-99m sestamibi dual-isotope myocardial perfusion SPECT and were followed up for at least 1 year (mean 20.0 ± 3.7 months). After censoring 59 patients with early coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, <60 days after nuclear testing, the final population consisted of 984 patients (36% women, mean age 63 ± 12 years).
Results. During the follow-up period, 28 hard events (14 cardiac deaths, 14 nonfatal myocardial infarctions) occurred. Patients with higher defect extent (>10%), severity (>150) and reversibility (>5%) by quantitative SPECT defect analysis, as well as those with an abnormal scan (>2 abnormal segments, summed stress score >4 and summed difference score >2) by semiquantitative visual SPECT analysis, had a significantly higher hard event rate compared to patients with a normal scan (p < 0.001). With both visual and quantitative analyses, hard event rates of approximately 1% with normal scans and 5% with abnormal scans (p > 0.05) were observed over the 20-month follow-up period. A Cox proportional hazards regression model showed that chi-square increased similarly with the addition of quantitative defect extent and visual summed stress score variables after considering both clinical and exercise variables (improvement chi-square = 11 for both, p < 0.0007). There were no significant differences in the areas under receiver operating characteristic curves between quantitative and visual analysis (p > 0.70). Linear regression analysis also indicated that quantitative assessments correlated well with visual semiquantitative assessments.
Conclusions. The findings of this study indicate that automatic quantitative analysis of exercise stress myocardial perfusion SPECT is similar to semiquantitative expert visual analysis for prognostic stratification. These findings may be of particular clinical importance in laboratories with less experienced visual interpreters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study validates a new quantitative perfusion SPECT algorithm for the assessment of myocardial perfusion. The algorithm is not based on slices and provides fully 3-dimensional sampling and ...analysis independent of assumptions about the geometric shape of the left ventricle.
Radiopharmaceutical- and sex-specific normal limits and thresholds for perfusion abnormality in 20 segments of the left ventricle were developed for separate, dual-isotope rest 201Tl-exercise 99mTc-sestamibi SPECT in 36 patients with <5% before-scanning likelihood of coronary artery disease (CAD) (group 1) and 159 patients with perfusion abnormalities (group 2). These thresholds were validated in 131 patients (group 3) by comparison with expert visual interpretation. Thresholds for automatic segmental scores were developed and validated for groups 2 and 3, respectively. The accuracy of CAD detection was assessed in 94 patients, who underwent coronary angiography (group 4).
Overall sensitivity for detection of stress and rest segmental perfusion abnormality was 91% and 96%, respectively, for men and 89% and 79%, respectively, for women. Overall specificity for stress and rest was 87% and 90%, respectively, for men and 88% and 90%, respectively, for women. Agreement between automatic and visual scores was good (weighted K of 0.71 and 0.60 for stress and rest images, respectively). Sensitivity and specificity were 88% for the detection of > or =70% stenosis. For the detection of left anterior descending, left circumflex, and right coronary artery stenosis, sensitivity was 84%, 86%, and 88%, respectively, and specificity was 84%, 88%, and 81%, respectively.
The new quantitative perfusion SPECT approach is highly sensitive and specific for the detection and localization of CAD, provides accurate automatic scores for the assessment of regional perfusion, and overcomes the low-specificity limitations of previous quantitative algorithms.
The combination of myocardial perfusion and poststress ejection fraction (EF) provides incremental prognostic information. This study assessed predictors of nonfatal myocardial infarction (MI) versus ...cardiac death (CD) by gated myocardial SPECT and examined the value of integrating the amount of ischemia and poststress EF data in risk stratification.
We identified 2,686 patients who underwent resting (201)Tl/stress (99m)Tc-sestamibi gated SPECT and were monitored for >1 y. Patients who underwent revascularization < or = 60 d after the nuclear test were censored from the prognostic analysis. Visual scoring of perfusion images used 20 segments and a scale of 0--4. Poststress EF was automatically generated.
Cox regression analysis showed that after adjusting for prescan data, the most powerful predictor of CD was poststress EF, whereas the best predictor of MI was the amount of ischemia (summed difference score SDS). Integration of the EF and SDS yielded effective stratification of patients into low-, intermediate-, and high-risk subgroups. Patients with EF >50% and a large amount of ischemia were at intermediate risk (2%--3%), whereas those with mild or moderate ischemia were at low risk of CD (<1%/y). Patients with EF between 30% and 50% were at intermediate risk even in the presence of only mild or moderate ischemia. In patients with EF <30%, the CD rate was high (>4%/y) irrespective of the amount of ischemia.
Poststress EF is the best predictor of CD, whereas the amount of ischemia is the best predictor of nonfatal MI. Integration of perfusion and function data improves stratification of patients into low, intermediate, and high risk of CD.
Effective allocation of medical resources in stable chest pain patients requires the accurate diagnosis of coronary artery disease and the stratification of future cardiac risk. We studied the ...relative predictive value for cardiac death of 3 commonly applied noninvasive strategies, clinical assessment, stress electrocardiography, and myocardial perfusion tomography, in a large, multicenter population of stable angina patients. The multicenter observational series comprised 7 community and academic medical centers and 8,411 stable chest pain patients. All patients underwent pretest clinical screening followed by stress (exercise 84% or pharmacologic 16%) electrocardiography and myocardial perfusion tomography. Risk-adjusted multivariable Cox proportional hazards models were developed to predict cardiac death. Kaplan-Meier rates of time to cardiac catheterization were also computed. Cardiac mortality was 3% during the 2.5 ± 1.5 years of follow-up. The number of infarcted vascular territories and pretest clinical risk factors were strong predictors of cardiac mortality, whereas the number of ischemic vascular territories gained increasing importance when determining post-test resource use requirements (i.e., the decision to perform cardiac catheterization). Exertional ST-segment depression in a population with a high frequency of electrocardiographic abnormalities at rest was not a significant differentiator of cardiac death risk. Stable chest pain patients are accurately identified as being at high risk for near-term cardiac events by both physicians’ screening clinical evaluation and by the results of stress myocardial perfusion imaging. Disease management strategies for stable chest pain patients aimed at risk reduction should incorporate knowledge of relevant end points in treatment and guideline development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background The clinical usefulness of a rapid rest low-dose/stress high-dose (dose ratio =1:5) 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) protocol for the ...detection of coronary artery disease was evaluated. Methods and Results In 89 patients, rest images were obtained immediately after the injection of 99mTc-sestamibi (256.1±28.4 MBq) followed by drinking water (400 ml). Exercise or vasodilator stress test was performed immediately after the completion of rest imaging with the injection of 99mTc-sestamibi (1312.3 ±167.6 MBq). Prior to the post-stress imaging, patients were asked again to drink water (400 ml) in order to eliminate subdiaphragmatic tracer activity. The myocardial count ratio (stress/rest) of 99mTc-sestamibi was calculated. Image quality was scored using a 4-point scale system (4= excellent, 3= good, 2= poor, 1= unacceptable). Coronary angiography was performed in 56 patients within 1 month of the SPECT scan. All patients successfully performed the protocol and total examination time was 108±7 min. The myocardial count ratio of 99mTc-sestamibi was always greater than 6. The image quality was satisfactory both at rest (3.4±0.9) and after stress (3.9±0.2). The sensitivity and specificity to detect coronary artery stenosis >50% was 84% and 97%, respectively. Conclusions This rapid one-day 99mTc-sestamibi protocol provides adequate image quality and diagnostic accuracy for detecting coronary artery disease. (Circ J 2006; 70: 1585 - 1589)
Background Previous studies have shown that myocardial perfusion single photon emission computed tomography (SPECT) provides incremental prognostic information in the general population, but the ...prognostic efficacy of nuclear testing in patients with diabetes mellitus is unclear.
Methods We conducted a study with 1271 consecutively registered patients with diabetes and 5862 patients without diabetes with known or suspected coronary artery disease undergoing rest thallium 201/stress technetium 99m sestamibi dual-isotope myocardial perfusion SPECT with exercise or adenosine pharmacologic testing. Patients were followed up for at least 1 year. The successful follow-up rate was 92.4% for patients with diabetes and 94.0% for subjects without diabetes. The mean follow-up period was 23.7 ± 7.7 months for the former group and 21.5 ± 6.1 months for the latter.
Results Over the follow-up period, patients with diabetes had significantly higher rates of hard events (cardiac death or nonfatal myocardial infarction) (4.3% per year versus 2.3% per year,
P < .001) and higher total event rates (hard events and late revascularization) (9.0% per year versus 5.3% per year,
P < .001) compared with rates among patients without diabetes. Cox proportional hazards analysis revealed that nuclear testing added incremental value over clinical and historical variables among patients with diabetes (global χ
2 increased 46% for the exercise group n = 619 and 88% for the adenosine group n = 461; both
P < .001). The event rates rose significantly as a function of summed stress score and summed difference score among both patients with diabetes and patients without diabetes (
P < .001). The patients with diabetes with normal scans had relatively low hard event rates (1% to 2% per year), those with mildly abnormal scans had intermediate hard event rates (3% to 4% per year), and those with moderately to severely abnormal scans had relatively high hard event rates (>7% per year).
Conclusions The results of this study indicated that exercise and adenosine stress myocardial perfusion SPECT are valuable for risk stratification and management of patients with diabetes. (Am Heart J 1999;138:1025-32.)
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background. Little is known about the prognostic value of myocardial perfusion single photon emission computed tomography (SPECT) in patients with remote prior myocardial infarction (MI). Methods and ...Results. We identified 1413 consecutive patients with remote prior MI who underwent rest-stress myocardial perfusion SPECT. Semiquantitative visual analysis of 20 SPECT segments was used to define the summed stress, rest, and difference scores. The number of non-reversible segments was used as an index of infarct size. During follow-up (≥1 year), 118 hard events occurred: 64 cardiac deaths (CDs) and 54 recurrent MIs. Annual CD and hard event rates increased significantly as a function of SPECT abnormality. For summed stress scores less than 4, 4 to 8, 9 to 13, and more than 13, the annual CD rates were 0.4%, 0.9%, 1.7%, and 3.5%, respectively (P = .002). Patients with small MI (<4 non-reversible segments) and no or mild ischemia (summed difference score ≤6) had an annual CD rate of 0.6%. Patients with small MI and moderate or severe ischemia had an annual CD rate of 1.6%, and those with large MI (≥4 non-reversible segments) had moderate to high annual CD rates (3.7%-6.6%) regardless of the extent of ischemia. Nuclear testing added incremental prognostic information to pre-scan information. Compared with a strategy in which all patients are referred to catheterization, a strategy that referred only those patients with a risk for CD of greater than 1% by myocardial perfusion SPECT resulted in a 41.6% cost savings. Conclusions. Myocardial perfusion SPECT adds incremental value to pre-scan information and is highly predictive and cost-efficient in the risk stratification of patients with remote prior MI. Patients with normal or mildly abnormal scan results or small MI in combination with absent or mild ischemia have a low risk for CD. (J Nucl Cardiol 2002;9:23-32.)
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EMUNI, NUK, SBMB, SBNM, UL, UPUK
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