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Biomedical subjects

D S Berman

Publications and source records attributed to D S Berman.

At least 271 records · Page 15Linked to original sources
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Rest and treadmill exercise first-pass radionuclide ventriculography: validation of left ventricular ejection fraction measurements.

BACKGROUND: To assess the accuracy of rest and treadmill exercise first-pass radionuclide ventriculographic measurements of left ventricular ejection fraction (LVEF), 40 patients underwent treadmill exercise first-pass and bicycle exercise equilibrium radionuclide ventriculography. To determine the frequency of technically adequate treadmill exercise first-pass studies, an additional 128 consecutive patients undergoing treadmill exercise first-pass procedures during stress 99mTc-labeled sestamibi myocardial perfusion studies were assessed. METHODS AND RESULTS: The treadmill exercise first-pass procedure used a multicrystal camera and an 241Am point source to allow for correction of patient motion. Excellent correlations were observed between resting first-pass and resting equilibrium LVEF (r = 0.91; standard error of the estimate = 5.6). A high correlation was also observed between treadmill exercise first-pass and bicycle equilibrium exercise LVEF measurements (r = 0.85, standard error of the estimate = 7.6). Treadmill first-pass LVEF systematically underestimated the bicycle equilibrium LVEF. Intraobserver agreement for rest and exercise first-pass LVEF was high (r values of 0.98 and 0.94, respectively). Of the 168 consecutive treadmill exercise first-pass studies evaluated for technical adequacy, 21 (12.5%) were deemed technically inadequate, with most of the sources of error being avoidable. The frequency of technically adequate studies was as high (87%) in high levels of exercise (Bruce stages 3 and 4) as in lower levels (88%). The findings of this study validate the first-pass treadmill exercise LVEF measurement. CONCLUSION: This procedure now provides the option for combining the information of peak treadmill exercise LVEF with measurements of exercise myocardial perfusion from the same injection of radioactivity.

Adult↗
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Comparative localization of myocardial ischemia by exercise electrocardiography and myocardial perfusion SPECT.

BACKGROUND: Prior angiographic study has shown that the patterns of ST-segment depression during exercise do not provide localizing information of the responsible coronary lesion. However, little is known regarding the ability of exercise-induced ST-segment displacement to localize myocardial perfusion defects. METHODS AND RESULTS: We studied 552 consecutive patients without prior myocardial infarction who had reversible perfusion defect in one vascular territory on rest 201Tl/exercise 99mTc-labeled sestamibi dual-isotope myocardial perfusion single photon emission computed tomography (SPECT) and ischemic ST depression or elevation during exercise. Of these, 192 patients had angiographically documented coronary artery disease (CAD). Two hundred thirty-two patients had maximal ST depression in anterior leads, 247 patients had maximal ST depression in inferior leads, and 45 patients had similar maximal ST depression in both anterior and inferior leads. Twenty-eight (5%) patients had ST elevation with absent Q waves. In patients with maximal ST depression in anterior leads, perfusion defects were found in the territory of the left anterior descending coronary artery (LAD) in 30%, in the territory of the right coronary artery (RCA) in 52%, and in the territory of the left circumflex coronary artery (LCX) in 18%. In patients with maximal ST depression in inferior leads, perfusion defects were found in RCA territory in 44%, in the LAD territory in 42%, and in the LCX territory in 14%. Compared with exercise ST depression, the less common finding of ST elevation did provide accurate localization of perfusion defects. When ST elevation was greatest in the anterior leads, 96% of patients had LAD territory defects. When ST elevation was most prominent in the inferior leads, 100% patients had RCA territory defects. Data of coronary angiograms demonstrated that myocardial perfusion SPECT correctly identified the most stenotic coronary disease for LAD (94%), LCX (72%), and RCA (75%). CONCLUSIONS: The findings of this study indicate that the site of maximal ST-segment depression does not identify the localization of myocardial perfusion defects. However, the less common finding of exercise-induced ST-segment elevation does predict localization of myocardial ischemia.

Adult↗
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Diagnostic efficacy of stress technetium 99m-labeled sestamibi myocardial perfusion single-photon emission computed tomography in detection of coronary artery disease among patients over age 80.

BACKGROUND: Because symptoms of myocardial ischemia in elderly patients are often atypical, accurate noninvasive assessment of the presence, extent, and severity of coronary artery disease (CAD) would be especially useful to avoid unnecessary catheterization or invasive intervention. This study assessed the safety and diagnostic efficacy of 99mTc-labeled sestamibi (99mTc-sestamibi) exercise and pharmacologic myocardial perfusion single-photon emission computed tomography (SPECT) with adenosine or dipyridamole in patients age 80 years or older. METHODS AND RESULTS: Stress 99mTc-sestamibi SPECT was performed in 75 consecutive patients who were 80 years old or older (range: 80 to 91 years) with suspected CAD and who underwent coronary angiography within 6 months of the nuclear study. Of these patients, 51 underwent a pharmacologic (adenosine = 42; dipyridamole = 9) stress study and 24 underwent an exercise treadmill study. A normalcy rate was derived from an additional 36 patients (ages 83 +/- 3 years) who had undergone stress 99mTc-sestamibi SPECT and who had a relatively low likelihood (< 20%) of CAD. No serious adverse events occurred during or after the exercise or the pharmacologic stress test. The overall sensitivity and specificity for detecting CAD with > or = 70% stenosis was 95% (52/55) and 75% (15/20), whereas the corresponding results were 87% (55/63) and 83% (10/12) for detecting patients with > or = 50% stenosis. The sensitivity and specificity for pharmacologic stress 99mTc-sestamibi SPECT were 95% (35/37) and 71% (10/14) for detecting > or = 70% stenosis, and 86% (37/43) and 75% (6/8) for detecting CAD with > or = 50% stenosis. The sensitivity and specificity of treadmill testing were 94% (17/18) and 83% (5/6) in detecting CAD with stenosis > or = 70% and 90% (18/20) and 100% (4/4) in detecting CAD with stenosis > or = 50%. The normalcy rate among the low likelihood patients was 83% (30/36). The accuracy of stress sestamibi testing was similar for patients with or without angina. CONCLUSIONS: Our findings suggest that exercise or pharmacologic myocardial perfusion SPECT with 99mTc-sestamibi is safe and diagnostically accurate for CAD detection in very elderly patients, irrespective of symptoms. Pharmacologic myocardial perfusion SPECT with adenosine or dipyridamole appears to be a valuable alternative to treadmill stress in very elderly patients incapable of performing adequate exercise.

Aged↗
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Fast technetium 99m-labeled sestamibi gated single-photon emission computed tomography for evaluation of myocardial function.

BACKGROUND: This study assesses the feasibility of 99mTc-labeled sestamibi electrocardiographic gated single-photon emission computed tomography (SPECT) with a short acquisition time (6.7 minutes, "fast" gated SPECT) for the evaluation of stress myocardial perfusion and poststress myocardial function. Simultaneous assessment of stress perfusion and poststress function is possible with standard gated SPECT acquisition (19.3 minutes) of stress-injected sestamibi. Sestamibi gated SPECT can be used to evaluate regional wall motion (RWM), thickening, and left ventricular ejection fraction (LVEF); the feasibility of fast gated SPECT has not been evaluated previously. METHODS AND RESULTS: Fifty patients were studied who underwent treadmill exercise, sestamibi injection (25 to 30 mCi), and standard gated SPECT 15 minutes after exercise, immediately followed by fast gated SPECT. All patients underwent rest 201Tl SPECT before exercise testing. All studies were analyzed by semiquantitative visual scoring. Both standard and fast gated SPECT were read for stress perfusion and poststress wall motion and thickening, dividing the left ventricle into 20 segments, on a 5-point scale described previously. The measurement of LVEF used a previously described automatic algorithm. Average myocardial counts per pixel were 58 +/- 19 for standard gated SPECT and 13 +/- 4 for fast gated SPECT (p = 0.0001). Heart/lung ratio was 10.2 +/- 4.8 for regular gated SPECT and 10.3 +/- 5.7 for fast gated SPECT (difference not significant). Perfusion analysis showed exact agreement in 92% of the segments (kappa = 0.76; p < 0.01). Correlation between LVEFs measured from standard and fast gated SPECT was 0.94. Analysis of 998 segments (two segments were uninterpretable) showed exact agreement in 96% (kappa = 0.89; p < 0.001) for RWM and 94% (kappa = 0.83; p < 0.001) for thickening between standard and fast gated SPECT. In 225 segments with abnormal RWM and 189 segments with abnormal thickening by both standard and fast gated SPECT, exact agreements were 0.92 for RWM (kappa = 0.90; p < 0.001) and 0.87 for thickening (kappa = 0.80; p < 0.01). CONCLUSIONS: Our data demonstrate that fast sestamibi gated SPECT is feasible and yields results equivalent to those of standard sestamibi gated SPECT with respect to left ventricular regional and global function.

Aged↗
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Effect of the number of projections collected on quantitative perfusion and left ventricular ejection fraction measurements from gated myocardial perfusion single-photon emission computed tomographic images.

BACKGROUND: Gated myocardial perfusion single-photon emission computed tomographic (SPECT) imaging is currently performed by step-and-shoot detector rotation, resulting in acquisition dead time and lengthened study duration compared with nongated SPECT imaging with continuous or pseudocontinuous rotation. Dead time is particularly undesirable in new fast-gated SPECT imaging protocols with inotropic pharmacologic stress. METHODS AND RESULTS: This article evaluated the influence of projections' angular spacing on quantitative measurements of left ventricular ejection fraction (LVEF) and perfusion from postexercise 99mTc-labeled sestamibi images. Gated 60-projection data sets from 30 patients were compacted into 30- and 15-projection sets. The three sets (corresponding to 3-, 6-, and 12-degree spacing over 180 degrees) were reconstructed into gated and ungated short-axis image sets. LVEFs were measured from the gated images according to a previously described automatic algorithm, whereas perfusion was assessed from the ungated images by a 20-segment division of their maximal pixel polar maps. LVEF values were essentially unchanged between 60- and 30-projection images (y = 0.37 + 0.996x; r = 0.999; standard error of the estimate = 0.56) and 60- and 15-projection images (y = 1.35 + 0.987x; r = 0.999; standard error of the estimate = 0.77) in the 30 patients. Overall, 30- and 15-projection polar maps differed by 1.87% +/- 1.24% and 4.38% +/- 2.25% from the 60-projection polar maps, respectively. Segmental perfusion score agreement between 60- and 30-projection images and between 60- and 15-projection images was 93% (kappa = 0.92; p < 0.001) and 83% (kappa = 0.81; p < 0.001), respectively. Sixty- and 30-projection images were visually undistinguishable, whereas loss of image resolution was noticed in many 15-projection gated and ungated images. CONCLUSIONS: Thirty-projection gated SPECT imaging is a practical, accurate, and time-saving approach in standard gated protocols and, potentially, fast-gated protocols. Fifteen-projection gated SPECT imaging is not generally recommended and should be considered only for LVEF assessment in conjunction with fast-gated protocols.

Aged↗
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Evaluation of ventricular ejection fraction, wall motion, wall thickening, and other parameters with gated myocardial perfusion single-photon emission computed tomography.

Assessment of ventricular function (e.g., ejection fraction, wall motion, wall thickening) during myocardial perfusion single-photon emission computed tomography (SPECT) can serve as a cost-effective technique to provide more diagnostic data with fewer diagnostic tests. With the advent of 99mTc-labeled perfusion agents and advances in technology, myocardial perfusion studies can be augmented on a routine basis to provide additional diagnostic information on ventricular function by use of one gated SPECT acquisition. This technique has the potential to reduce health-care costs by reducing the number of unnecessary coronary angiographies that are now performed on patients with equivocal results of perfusion or incomplete risk stratification from standard myocardial perfusion SPECT.

Coronary Disease↗
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Validation of left ventricular volume measurements by gated SPECT 99mTc-labeled sestamibi imaging.

BACKGROUND: Previous studies have shown that gated single photon emission computed tomography (SPECT) technetium 99-labeled sestamibi imaging provides accurate and reproducible measurement of left ventricular (LV) ejection fraction (EF), wall motion, and thickening. This study examined the reliability of gated SPECT sestamibi imaging in measuring LV end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV). METHODS AND RESULTS: Gated SPECT measurements were compared with an independent nongeometric method based on thermodilution SV and first-pass radionuclide angiographic EF (using a multicrystal gamma camera). Twenty-four patients aged 58+/-11 years underwent cardiac catheterization and coronary angiography for evaluation of chest pain syndromes. None had primary valvular disease, intracardiac shunts, or atrial fibrillation. RESULTS: The correlation between the two methods were as follows: EDV: r = 0.89, P<.001; ESV: r = .938, P<.001; SV: r = 0.577, P<.001. Bland-Altman plots showed mean differences (+/-standard deviation [SD]) for EDV of -14.3+/-33.3 mL, for ESV of -0.4+/-23.7 mL, and for SV of -13.9+/-15.2 mL. The reproducibility of measuring EDV and ESV by gated SPECT was very high (r = 0.99 each). CONCLUSION: Gated 99mTc-labeled sestamibi SPECT provides reproducible LV volume measurements. With validation of volume measurement, gated SPECT provides comprehensive assessment of regional and global LV function. This information is important in many patient groups such as those with ischemic cardiomyopathy, concomitant coronary and valve disease, and those who have had myocardial infarction. It will also be useful to assess the incremental value of LV volumes in risk assessment.

Cardiac Output↗
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Repeatability of automatic left ventricular cavity volume measurements from myocardial perfusion SPECT.

BACKGROUND: This study sought to assess the repeatability of automatic quantitative measurements of left ventricular (LV) cavity volumes in a large patient population (N = 926), to correlate those measurements to similarly obtained LV ejection fraction (LVEF) measurements, and to investigate the relationship between ungated and gated volumes. METHODS: All 926 patients underwent ungated single photon emission computed tomography (SPECT) immediately followed by 8-frame gated SPECT. LV cavity volumes were automatically measured from ungated (V), summed gated (SUMV), end-systolic (ESV) and end-diastolic (EDV) images, and LVEFs derived from the latter 2. RESULTS: Repeatability (SUMV vs V) was very good overall (6.4%+/-6.6%), further improving for volumes >25 mL (5.7%+/-5.5%) and >40 mL (5.2%+/-5.0%). Exponential regression between ESV and LVEF (r = 0.925, SEE = 15.0 mL), EDV and LVEF (r = 0.802, SEE = 24.2 mL), and SUMV and LVEF (r = 0.867, SEE = 19.7 mL) was also very good. Summed gated volumes were closer to ESV than to EDV (43.3%+/-8.8% of EDV-ESV range). SUMV <50 mL and SUMV >110 mL were good substitutes for LVEF >50% and LVEF <40% (93.4% and 97.1%, respectively). CONCLUSION: Automatic quantitative measurements of gated and ungated volumes with our algorithm are repeatable, correlate well with other global myocardial parameters, and may contribute important additional information to that conventionally provided by myocardial perfusion SPECT studies.

Adult↗
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Automatic quantification of left ventricular ejection fraction from gated blood pool SPECT.

BACKGROUND: Cardiac gated blood pool single photon emission computed tomography (GBPS) better separates cardiac chambers compared with planar radionuclide ventriculography (PRNV). We have developed a completely automatic algorithm to measure quantitatively the left ventricular ejection fraction (LVEF) from gated technetium 99m-red blood cells (RBC) GBPS short-axis 3-dimensional image volumes. METHODS AND RESULTS: The algorithm determines an ellipsoidal coordinate system for the left ventricle and then computes a static estimate of the endocardial surface by use of counts and count gradients. A dynamic surface representing the endocardium is computed for each interval of the cardiac cycle by use of additional information from the temporal Fourier transform of the image data sets. The algorithm then calculates the left ventricular volume for each interval and computes LVEF from the end-diastolic and end-systolic volumes. The algorithm was developed in a pilot group (N = 45) and validated in a second group (N = 89) of patients who underwent PRNV and 8-interval GBPS. Technically inadequate studies (N = 38) were rejected before grouping and processing. Automatic identification and contouring of the left ventricle was successful in 121/172 patients (70%) globally and in 76/89 patients (85 %) in the validation group. Correlation between LVEFs measured from GBPS and PRNV was high (y = 2.00 + 1.01x, r = 0.89), with GBPS LVEF significantly higher than PRNV LVEF (average difference = 2.8%, P < .004). CONCLUSIONS: Our automatic algorithm agrees with conventional radionuclide measurements of LVEF and provides the basis for 3-dimensional analysis of wall motion.

Algorithms↗
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Cost analysis of diagnostic testing for coronary artery disease in women with stable chest pain. Economics of Noninvasive Diagnosis (END) Study Group.

BACKGROUND: Seven clinical sites compiled data from 4638 women who were referred directly to coronary angiography (catheterization-first strategy; n = 3375) or who underwent stress myocardial perfusion imaging (MPI) first (n = 1263) followed by coronary angiography if at least one reversible myocardial perfusion abnormality was detected. The study examines the cost minimization potential of these available invasive and noninvasive diagnostic strategies in women with chest pain. METHODS AND RESULTS: Women in both groups were subclassified by the core laboratory as being at low (<0.15), intermediate (0.15 to 0.60), or high (>0.60) pretest likelihood for coronary artery disease (CAD). Among the catheterization-first patients, at least one coronary stenosis >70% was present in 13% of low likelihood patients, 29% of intermediate likelihood patients, and 52% of patients with high CAD likelihood. Perfusion abnormality rates in the MPI-first group were 23% in low likelihood patients, 27% in intermediate likelihood patients, and 34% in high CAD likelihood patients. Of the MPI-first subset, 50%, 55%, and 76%, respectively, underwent catheterization in at least one coronary stenosis >70%. Cardiac death rates ranged from 0.5% to 2.2% in patients with CAD and did not differ from the 2 testing strategies (P = not significant). The composite cost per patient of diagnostic testing plus follow-up medical care over a period of 2.5 +/- 1.5 years (calculated for both strategies from inflation-corrected Medicare charges, adjusted for institutional cost-charge ratios) ranged from $2490 for patients with low likelihood to $3687 for patients with high likelihood with the catheterization-first strategy and from $1587 to $2585 for patients undergoing MPI first (P < .01 between risk subsets and strategies). CONCLUSIONS: In women referred for diagnostic evaluation of stable chest pain, MPI followed by selective coronary angiography in patients with at least 1 perfusion abnormality minimizes the near-term composite cost per patient compared with a direct catheterization-first strategy, regardless of pretest CAD likelihood.

Aged↗
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Methodological considerations in the assessment of noninvasive testing using outcomes research: pitfalls and limitations.

The ongoing demands for cost-containment in medicine have radically altered the practice of medicine in general and the practice of cardiology in particular. The need to justify the use of noninvasive testing has led to the development of outcomes data to validate the use of these tests and show their cost-effectiveness when incorporated into testing strategies. The development of a supportive literature of noninvasive modalities, however, requires an understanding of the varied methodological approaches that constitute outcomes research. The proper use of these methods, the interpretation of their results, and the application of these results to clinical practice are potentially problematic. This review focuses on the use and limitations of the methods used for outcomes-based assessment of technology and examples of their application.

Cost-Benefit Analysis↗
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Sustained reduction of exercise perfusion defect extent and severity with isosorbide mononitrate (Imdur) as demonstrated by means of technetium 99m sestamibi.

BACKGROUND: The impact of long-acting nitrates on the extent and severity of stress-induced myocardial ischemia is not well described, especially after long-term treatment. METHODS: Forty patients with chronic stable angina and reversible ischemia on an exercise stress myocardial perfusion single photon emission computed tomography (ex-SPECT) were prospectively studied in a 6-week period. At baseline, rest thallium-201/exercise stress technetium 99m sestamibi SPECT was performed, followed by treatment with extended-release isosorbide 5-mononitrate (5-ISMN, Imdur). Follow-up ex-SPECT was performed 5 days and 6 weeks after the initiation of therapy with extended-release 5-ISMN. The exercise treadmill testing (ETT) protocol and exercise duration of the follow-up studies were the same as that of the baseline ETT. Defect extent and severity were analyzed both by means of an automated quantitative method, with CEqual software, and visually, with a 20-segment scoring system (which was also used to derive a summed stress score [SSS]). RESULTS: In the 6-week study period, significant reductions occurred in both the extent and the severity of exercise-induced ischemia by means of quantitative SPECT (13.8% [P<.0003] and 12.7% [P<.0003], respectively). There was no significant change in these variables between stages 2 (day 5) and 3 (6 weeks), indicating no development of tolerance to the nitrate effect. Similar reductions were noted by means of the visual analysis (SSS reduction of 13.0% [P<.002]) in the entire study period. CONCLUSIONS: Patients with chronic-stable-angina treated with a long-acting nitrate demonstrate improvement in myocardial perfusion defect extent and severity in an extended period by means of both visual and quantitative analysis of sequential exercise testing to the same rate-pressure product end point.

Aged↗