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Biomedical subjects

D S Berman

Publications and source records attributed to D S Berman.

At least 19 recordsLinked to original sources
PubMed2004

Modern nuclear cardiac imaging in diagnosis and clinical management of patients with left ventricular dysfunction.

Congestive heart failure (CHF) has become a large social burden in modern Western society, with very high morbidity and mortality and extremely large financial costs. The largest cause of CHF is coronary heart disease, with ventricular dysfunction that may or may not be reversible by revascularization. Thus, evaluation of the viable myocardial tissue in patients with ischemic left ventricular (LV) dysfunction has important clinical and therapeutic implications. Furthermore, since patients with ventricular dysfunction are at higher operative risk, cardiologists and cardiac surgeons are commonly faced with issues regarding the balance between the potential risk vs benefit of revascularization procedures. Cardiac nuclear imaging [myocardial perfusion SPECT (MPS) and positron emission tomography (PET)] provide objective information that augments standard clinical and angiographic assessments of patients with ventricular dysfunction with respect to diagnosis (etiology), prognosis, and potential benefit from intervention. Development of the technology and methodology of gated MPS, now the routine method for MPS, allows assessment of the extent and severity of inducible ischemia as well as hypoperfused but viable myocardium, and also provides measurements of LV ejection fraction, regional wall motion, LV volume measurements, diastolic function and LV geometry. With PET, myocardial metabolism and blood flow reserve can be added to the measurements provided by nuclear cardiology procedures. This paper provides insight into the current evidence regarding settings in which nuclear cardiac imaging procedures are helpful in assessment of patients in the setting of coronary artery disease with severe LV dysfunction. A risk-benefit approach to MPS results is proposed, with principal focus on identifying patients at risk for major cardiac events who may benefit from myocardial revascularization.

Forecasting↗
PubMed2001

Nuclear cardiology and electron-beam computed tomography: competitive or complementary?

Electron-beam computed tomography (EBCT) and nuclear cardiology techniques are both valuable in the noninvasive assessment of patients with suspected coronary artery disease. The techniques, however, are different in the information they provide about the patient. EBCT provides anatomic information on coronary atherosclerosis, whereas myocardial perfusion single-photon emission computed tomography assesses the physiologic significance of coronary stenosis. Because of these differences, the techniques are highly complementary. In considering the complementary nature of these methods, it is important to clarify the issues being raised. An important question in the consideration of a patient with known or suspected coronary artery disease is, What is the risk in an individual patient of developing clinical coronary artery disease? The answer to this question will determine who needs aggressive medical management. A second question in a suspected coronary artery disease patient is, What is the risk of cardiac death? As will be discussed, this risk, in general, determines the need to consider coronary revascularization. In the former question, EBCT testing and clinical assessment alone is usually sufficient, and in some cases nuclear testing can be of additional value. In answering the second question, on the basis of currently available data, the EBCT and nuclear cardiology studies appear to be operating in a complementary fashion.

Cholesterol↗
PubMed2001

When to stress patients after coronary artery bypass surgery? Risk stratification in patients early and late post-CABG using stress myocardial perfusion SPECT: implications of appropriate clinical strategies.

OBJECTIVES: The study compared the prognostic significance of myocardial perfusion single-photon emission computed tomography (SPECT) (MPS) in patients early and late after coronary artery bypass graft surgery (CABG). BACKGROUND: The long-term effectiveness of CABG is limited by graft stenosis. The greatest incidence of graft occlusion occurs between five and eight years after surgery. However, little is known regarding the appropriate time to stress patients post-CABG with respect to risk stratification. METHODS: We identified 1,765 patients, who underwent MPS 7.1 +/- 5.0 years post-CABG. All patients underwent rest T1-201/stress Tc-99m sestamibi MPS and were followed up > or =1 year after testing. Patients with early CABG or PTCA (<60 days after MPS) were censored. The prognostic population consisted of 1,544 patients. A semiquantitative visual analysis employing a 20-segment model was used to define summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), and the number of nonreversible segments (NRS). RESULTS: During follow-up, 53 cardiac deaths (CD) occurred. There was a significant increase in annual CD rates as a function of SSS. A multivariate analysis identified age, ischemia (SDS), and infarct size (NRS) as independent predictors of CD. Nuclear variables added incremental value to prescan information. The annual CD rate was relatively low (1.3%) in patients < or =5 years post-CABG. In this subgroup only age and infarct size (NRS) were predictive of CD. CONCLUSION: MPS is strongly predictive of subsequent CD in post-CABG patients and adds incremental value over clinical and treadmill test information. Our data suggest that symptomatic patients < or =5 years and all patients >5 years post-CABG may benefit from testing.

Aged↗
PubMed2001

Association of mitral annulus calcification, aortic valve sclerosis and aortic root calcification with abnormal myocardial perfusion single photon emission tomography in subjects age < or =65 years old.

OBJECTIVES: We examined the hypothesis that mitral annulus calcification (MAC), aortic valve sclerosis (AVS) and aortic root calcification (ARC) are associated with coronary artery disease (CAD) in subjects age < or =65 years. BACKGROUND: Mitral annulus calcification, AVS and ARC frequently coexist and are associated with coronary risk factors and CAD in the elderly. METHODS: We studied 338 subjects age < or =65 years who underwent evaluation of chest pain with myocardial perfusion single photon emission computed tomography (SPECT) and a two-dimensional transthoracic echocardiogram for other indications. The association of MAC, AVS and ARC with abnormal SPECT was evaluated by using chi-square analyses and logistic regression analyses. RESULTS: Compared with no or one calcium deposit and no or one coronary risk factor other than diabetes, multiple (> or =2) calcium (or sclerosis) deposits with diabetes or multiple (> or =2) coronary risk factors were significantly associated with abnormal SPECT in women age < or =55 years old (odds ratio [OR], 20.00), in women age >55 years old (OR, 10.00) and in men age < or =55 years old (OR, 5.55). Multivariate analyses identified multiple calcium deposits as a significant predictor for an abnormal SPECT in women (p < 0.001), younger subjects age < or =55 years (p < 0.05) and the total group of subjects (p < 0.01). CONCLUSIONS: When coronary risk factors are also taken into consideration, the presence of multiple calcium deposits in the mitral annulus, aortic valve or aortic root appears to be a marker of CAD in men < or =55 years old and women.

Aged↗
PubMed2001

Quantitative assessment of motion artifacts and validation of a new motion-correction program for myocardial perfusion SPECT.

UNLABELLED: Patient motion during myocardial perfusion SPECT can produce images that show artifactual perfusion defects. The relationship between the degree of motion and the extent of artifactual perfusion defects is not clear for either single- or double-head detectors. Using both single- and double-head detectors and quantitative perfusion SPECT (QPS) software, we studied the pattern and extent of defects induced by simulated motion and validated a new automatic motion-correction program for myocardial perfusion SPECT. METHODS: Vertical motion was simulated by upward shifting of the raw projection datasets in a returning pattern (bounce) and in a nonreturning pattern at 3 different phases of the SPECT acquisition (early, middle, and late), whereas upward creep was simulated by uniform shifting throughout the acquisition. Lateral motion was similarly simulated by left shifting of the raw projection datasets in a returning pattern and in a nonreturning pattern. Simulations were performed using single- and double-head detectors, and simulated motion was applied to projection images from 8 patients who had normal 99mTc-sestamibi SPECT findings. Additionally, images from 130 patients with actual clinical motion were assessed before and after motion correction. The extent of perfusion defects was assessed by QPS, and a 20-segment, 5-point scoring system was used to assess the effect of motion on the presence and extent of perfusion defects. RESULTS: Of 12 bounce simulations, the bouncing motion failed to produce significant (>3%) perfusion defects with either the single- or the double-head detector. With the single-head detector, early shifting created the largest defect, whereas with the double-head detector, shifting during the middle of the acquisition created the largest defect. With regard to upward creep, defects were of larger extent with the double- than the single-head detector. With the single-head detector, 8 of 20 simulated motion patterns yielded significant perfusion defects of the left ventricle, 7 (88%) of which were significantly improved after motion correction. With the double-head detector, 12 of 20 patterns yielded significant defects, all of which improved significantly after correction. Of 2,600 segments in the 130 patients with actual clinical motion, only 1.3% (30/2,259) of segments that were considered normal (score = 0 or 1) changed to abnormal (score = 2-4) after motion correction, whereas 27% (92/341) of abnormal segments were reclassified as normal after motion correction. CONCLUSION: Artifactual perfusion defects created by simulated motion are a function of the time, degree, and type of motion and the number of camera detectors. Application of an automatic motion-correction algorithm effectively decreases motion artifacts on myocardial perfusion SPECT images.

Aged↗
PubMed2001

Prediction of myocardial infarction versus cardiac death by gated myocardial perfusion SPECT: risk stratification by the amount of stress-induced ischemia and the poststress ejection fraction.

UNLABELLED: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Adenosine↗
PubMed2001

Evidence-based risk assessment in noninvasive imaging.

UNLABELLED: Assessment of important clinical and economic outcomes has become central to the evaluation of patient care. Outcome research is deeply rooted in epidemiology, including the use of multivariable, risk-adjusted regression analysis. In our current health care environment, these methods are increasingly being used to assess the quality of care and to profile physicians and laboratories. Nuclear medicine physicians therefore need to better understand outcome methodologies in order to evaluate patient outcomes, develop guidelines, and decide on patient management. METHODS: This review describes the methods of assessing the diagnostic and prognostic value of nuclear medicine techniques and, briefly, the methodologic limitations of sample size, frequency and type of events, and follow-up periods and the incremental value of imaging. Also described are logistic regression and Cox proportional hazards modeling. Models for risk assessment are designed to identify whether patients require conservative (i.e., low-risk) or aggressive (i.e., high-risk) treatment. Treatment selection is currently based on risk assessment and the formation of an integrated, empiric risk stratification algorithm of care. This review also includes the methods of assessing economic effectiveness and quality-of-life issues for patients examined with nuclear medicine techniques. CONCLUSION: In this era of constrained resources, low-cost outpatient-based care may be of increasing importance. High-quality evidence of the clinical and economic outcome of nuclear imaging is essential for helping health care providers and payers assess its value.

Cardiovascular Diseases↗
PubMed2001

Quantitative analysis of regional motion and thickening by gated myocardial perfusion SPECT: normal heterogeneity and criteria for abnormality.

UNLABELLED: Quantitation of regional myocardial function is valuable in patients with coronary artery disease. This study assessed normal heterogeneity and developed and validated normal limits for quantitative regional motion and thickening by gated myocardial perfusion SPECT. METHODS: Patients underwent rest (201)Tl/exercise (99m)Tc-sestamibi gated SPECT. Reference values of motion and thickening for 20 myocardial segments were obtained in 105 patients with <5% likelihood of coronary disease (low-likelihood group). Criteria for abnormality of motion and thickening were defined for each segment, using receiver operator characteristic analysis, in 101 patients with coronary disease (training group). Semiquantitative visual interpretation was used as the gold standard. These criteria were prospectively validated in 100 patients (validation group). Criteria for grading motion and thickening abnormalities by severity levels were also defined and validated. RESULTS: Normal thickening decreased substantially along the longitudinal axis of the left ventricle, from 69% +/- 13% at the apex to 25% +/- 11% at the basal segments, whereas normal motion varied within the same ventricular plane. Validation of the criteria for abnormality yielded high accuracy in the detection of motion abnormalities (sensitivity, 88%; specificity, 92%) and thickening abnormalities (sensitivity, 87%; specificity, 89%). Quantitative motion and thickening segmental scores showed good agreement with visual scores. CONCLUSION: Normal regional myocardial contraction by gated myocardial perfusion SPECT is characterized by a substantial apex-to-base decline in thickening and by circumferential heterogeneity in endocardial motion. The assignment of segment-specific threshold values for defining motion and thickening abnormalities provided reasonably accurate identification and grading of regional myocardial dysfunction.

Aged↗
PubMed2000

Identification of severe and extensive coronary artery disease by postexercise regional wall motion abnormalities in Tc-99m sestamibi gated single-photon emission computed tomography.

Postexercise wall motion abnormality (WMA) in patients with normal resting myocardial perfusion may represent prolonged postischemic stunning, and may be related to the presence of severe angiographic coronary artery disease (CAD). This study assesses the diagnostic value of postexercise WMA by technetium-99m (Tc-99m) sestamibi gated single-photon emission computed tomography (SPECT) in patients with normal resting perfusion. Ninety-nine patients underwent exercise gated Tc-99m sestamibi/resting thallium-201 SPECT and coronary angiography within 90 days of nuclear testing. All patients had normal perfusion at rest. Multivariate logistic regression analysis demonstrated an incremental value of wall motion and perfusion over perfusion data alone in identifying severe and extensive CAD. Sensitivity for identifying any severely stenosed coronary artery by WMA was significantly higher than by severe perfusion defect (78% vs 49%, p <0.0001). Overall specificities of severe perfusion defect and WMA were 91% and 85%, respectively (p = NS). Thus, postexercise WMA detected by gated Tc-99m sestamibi SPECT in patients with normal resting perfusion is a sensitive marker of severe and extensive CAD.

Aged↗
PubMed2000

Early Permian bipedal reptile.

A 290-million-year-old reptilian skeleton from the Lower Permian (Asselian) of Germany provides evidence of abilities for cursorial bipedal locomotion, employing a parasagittal digitigrade posture. The skeleton is of a small bolosaurid, Eudibamus cursoris, gen. et sp. nov. and confirms the widespread distribution of Bolosauridae across Laurasia during this early stage of amniote evolution. E. cursoris is the oldest known representative of Parareptilia, a major clade of reptiles.

Animals↗
PubMed2000

Noninvasive strategies for the estimation of cardiac risk in stable chest pain patients. The Economics of Noninvasive Diagnosis (END) Study Group.

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.

Aged↗
PubMed2000

An economic analysis of an aggressive diagnostic strategy with single photon emission computed tomography myocardial perfusion imaging and early exercise stress testing in emergency department patients who present with chest pain but nondiagnostic electrocardiograms: results from a randomized trial.

STUDY OBJECTIVE: Conventional emergency department testing strategies for patients with chest pain often do not provide unequivocal diagnosis of acute coronary syndromes. This study was conducted to determine whether the routine use of single photon emission computed tomography (SPECT) imaging at rest and early exercise stress testing to assess intermediate-risk patients with chest pain and no ECG evidence of acute ischemia will lead to earlier discharges, more discriminate use of coronary angiography, and an overall reduction in average costs of care with no adverse clinical outcomes. METHODS: All patients in this study had technetium 99m tetrofosmin SPECT imaging at rest and were randomly assigned to either a conventional (results of the imaging test blinded to the physician) or perfusion imaging-guided (results of the imaging test unblinded to the physician) strategy. Patients in the conventional arm were treated at their physician's discretion. Patients in the perfusion imaging-guided arm were treated according to a predefined protocol based on SPECT imaging test results: coronary angiography after a positive scan result and exercise treadmill testing after a negative scan result. Study endpoints consisted of total in-hospital costs and length of stay. Hospital costs were calculated using hospital department-specific Medicare cost/charge ratios. Length of stay was calculated as total hospital room days billed (regular and intensive care). RESULTS: We enrolled 46 patients, 9 with acute myocardial infarctions. Patients randomly assigned to the perfusion imaging-guided arm had $1,843 (95% confidence interval [CI] $431 to $6,171) lower median in-hospital costs and 2.0-day (95% CI 1.0 to 3.0 days) shorter median lengths of stay but similar rates of in-hospital and 30-day follow up events as patients in the conventional arm. CONCLUSION: An ED chest pain diagnostic strategy incorporating acute resting (99m)Tc tetrofosmin SPECT imaging and early exercise stress testing may lead to reduced in-hospital costs and decreased length of stay for patients with acute chest pain and nondiagnostic ECGs.

Aged↗
PubMed2000

Enhanced prognostic stratification of patients with left ventricular hypertrophy with the use of single-photon emission computed tomography.

BACKGROUND: Patients with left ventricular hypertrophy (LVH) are at increased risk of future cardiovascular events. Little is known about risk stratification of these patients with the use of myocardial perfusion imaging. This study sought to assess the prognostic stratification of patients with LVH by using myocardial perfusion single-photon emission computed tomography (SPECT). METHODS AND RESULTS: We studied 633 consecutive patients with electrocardiographic evidence of LVH who underwent dual isotope myocardial perfusion SPECT (rest thallium 201/stress technetium 99m sestamibi) and were followed up for a mean period of 22 +/- 7 months. During the follow-up period, 67 events (35 cardiac deaths and 32 nonfatal myocardial infarctions) occurred (6% annual event rate). The results of the perfusion scan significantly risk-stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (<1% per year of follow-up). The rates of cardiac events increased significantly as a function of the scan result: 4.9% in patients with mildly abnormal scans and 10. 3% in moderately to severely abnormal scans. Cox proportional hazards analysis demonstrated that after adjusting for pretest likelihood of coronary artery disease (the most predictive clinical variable; chi(2) = 15.5, P <.001), summed stress score (the most predictive nuclear variable; chi(2) = 18, P <.0001) added significant incremental prognostic information (global chi(2) increased from 15.5 to 36; P <.001). CONCLUSIONS: In patients with LVH with an overall high cardiac event rate, SPECT provided enhanced stratification by adding significant incremental prognostic information over clinical and historic variables.

Aged↗
PubMed2000

The clinical value of assessing left ventricular function from gated SPECT perfusion studies.

Gated myocardial perfusion SPECT is a technique that is rapidly becoming widespread in the nuclear cardiology arena, and it currently accounts for a majority of all perfusion SPECT acquisitions performed in the USA. Its main advantage is that of providing important incremental clinical information over SPECT perfusion assessment alone, at essentially no extra cost. With respect to the diagnosis of cardiac disease, gated SPECT has been demonstrated to improve specificity by helping identify attenuation artifacts in patients with suspected coronary artery disease, and is also key in identifying patients with non-ischemic cardiomyopathies. In prognostic assessment, gated SPECT-derived measurements of ejection fraction achieve substantial incremental stratification of patients at risk for cardiac death or myocardial infarction, compared to perfusion scores, and volume measurements further improve risk stratification. New quantitative algorithms allow the fast, accurate and reproducible measurement of parameters of global cardiac function (ejection fraction, end-systolic and end-diastolic volume) as well as regional cardiac function (myocardial wall motion and thickening), all of which have been validated against a wide variety of gold standards.

Coronary Disease↗
PubMed2000

A new algorithm for the quantitation of myocardial perfusion SPECT. I: technical principles and reproducibility.

UNLABELLED: We have developed a new, completely automatic 3-dimensional software approach to quantitative perfusion SPECT. The main features of the software are myocardial sampling based on an ellipsoid model; use of the entire count profile between the endocardial and epicardial surfaces; independence of the algorithm from myocardial shape, size, and orientation and establishment of a standard 3-dimensional point-to-point correspondence among all sampled myocardial regions; automatic generation of quantitative measurements and 5-point semiquantitative scores for each of 20 myocardial segments and automatic derivation of summed perfusion scores; and automatic generation of normal limits for any given patient population on the basis of data fractionally normalized to minimize hot spot artifacts. METHODS: The new algorithm was tested on the tomographic images of 420 patients studied with a rest 201TI (111-167 MBq, 35 s/projection)-stress 99mTc-sestamibi (925-1480 MBq, 25 s/projection) separate dual-isotope protocol on a single-detector camera, a dual-detector 90 degrees camera, and a triple-detector camera. RESULTS: The algorithm was successful in 397 of 420 patients (94.5%) and 816 of 840 image datasets (97.1%), with a statistically significant difference between the success rates of the 201TI images (399/ 420, or 95.0%) and the 99mTc images (417/420, or 99.3%; P < 0.001). Algorithm failure was caused by extracardiac uptake (10/24, or 41.7%) or inaccurate identification of the valve plane because of low count statistics (14/24, or 58.3%) and was obviated by simply limiting the image volume in which the software operates. Reproducibility of measurements of summed perfusion scores (r = 0.999 and 1 for stress and rest, respectively), global defect extent (r = 0.999 and 1 for stress and rest, respectively), and segmental perfusion scores (exact agreement = 99.9%, kappa = 0.998 for stress and 0.997 for rest) was extremely high. CONCLUSION: Automatic 3-dimensional quantitation of perfusion from 201Tl and 99mTc-sestamibi images is feasible and reproducible. The described software, because it is based on the same sampling scheme used for gated SPECT analysis, ensures intrinsically perfect registration of quantitative perfusion with quantitative regional wall motion and thickening information, if gated SPECT is used.

Algorithms↗