Search PubMed⌕ Search

Biomedical subjects

D S Berman

Publications and source records attributed to D S Berman.

At least 109 records · Page 6Linked to original sources
PubMed1993

Effect of motion on thallium-201 SPECT studies: a simulation and clinical study.

Although patient motion on 201Tl SPECT studies has been reported as a source of artifacts, systematic studies on motion patterns and resultant artifacts are lacking. Accordingly, we simulated 74 motion patterns upon a normal study. The tomograms were assessed for presence of defects: The "motion pixel area index" ranged from 1 to 83; 26 of 30 (87%) simulations with an index > or = 21 had defects, whereas 38 of 44 (86%) simulations with an index < 21 were normal. Defect location was dependent on motion direction; defect intensity was dependent on its magnitude and timing. Review of data acquisition in 164 recent normal patient studies revealed motion in 42 (26%). Motion was generally minimal and caused defects in only seven (4%). Thus, mild motion is unlikely to produce defects. In our laboratory, motion is now an infrequent source of artifacts; severe motion produces recognizable patterns that depend on its direction, magnitude and timing.

Adult↗
PubMed1993

Detection and correction of patient motion in dynamic and static myocardial SPECT using a multi-detector camera.

We have developed a method for the detection and correction of translational patient motion in dynamic and static myocardial SPECT studies. The method uses a low activity 99mTc point source and is especially designed for multi-detector cameras. The source's centroid coordinates are measured or derived for all projection images in a temporal frame. The coordinate curves fitted to predicted distributions and the projection images shifted to realign measured to fitted values, with sub-pixel accuracy. In dynamic studies, the frame with the best fits serves as reference for all others. The accuracy of this method, measured with cardiac phantom experiments, was found to be +/- 0.37 mm and +/- 0.44 mm in the axial and transaxial dimension, respectively. By comparison, overall motion in 42 patients undergoing 99mTc-teboroxime dynamic cardiac SPECT studies was +/- 1.6 mm and +/- 1.2 mm, respectively (average on 39,272 projection views). Application of the method to phantom experiments, 99mTc-sestamibi and 99mTc-teboroxime human studies visually eliminated artifactual perfusion defects from simulated phantom motion and actual patient motion.

Gamma Cameras↗
PubMed1993

Myocardial perfusion imaging using technetium-99m radiopharmaceuticals.

Research and development in nuclear cardiology have made major contributions to the noninvasive approach for detection of coronary artery disease, to the assessment of disease extent and severity, and for prognostication of cardiac events. This article discusses the use of myocardial perfusion imaging and describes techniques for the evaluation of myocardial viability.

Coronary Circulation↗
PubMed1993

Quantitative same-day rest-stress technetium-99m-sestamibi SPECT: definition and validation of stress normal limits and criteria for abnormality.

Gender-matched stress normal limits and criteria for abnormality for rest-stress 99mTc-sestamibi same-day myocardial perfusion imaging were developed and validated in 160 patients who were imaged using previously developed optimized acquisition, processing and quantitative protocols. The gender-matched mean and standard deviation of the normal response were calculated using 35 male and 25 female patients with a < 5% likelihood of coronary artery disease. Receiver-operating curve analysis using expert visual interpretation as the "gold standard" was used to determine the optimal criteria for abnormality detection, in terms of standard deviations from the mean and minimum defect size for each of the four major zones of the polar map, in a pilot population consisting of an additional 35 male and 25 female patients with a variety of perfusion defects. The optimum standard deviations resulted in the following true-positive/true-negative rates when quantitative results were compared to visual analysis for the anterior, septal, lateral, and inferior segments in the combined male and female pilot populations: 84%/86%, 70%/75%, 86%/76% and 69%/76%, respectively. The final criteria were then applied to a prospective population consisting of 33 male and 7 female patients. This analysis resulted in the following true-positive/true-negative rates for overall perfusion abnormalities and abnormalities of the LAD, LCX and RCA vascular territories: 97%/67%, 94%/73%, 73%/90% and 72%/91%, respectively. The optimized 99mTc-sestamibi stress normal limits and criteria for abnormality correlate well with expert visual interpretation of stress myocardial perfusion defects.

Coronary Disease↗
PubMed1992

Reproducibility of stress redistribution thallium-201 SPECT quantitative indexes of hypoperfused myocardium secondary to coronary artery disease.

To determine the reproducibility of quantitative indexes of hypoperfused myocardium by exercise thallium-201 single-photon emission computed tomography, duplicate studies were performed in 16 stable patients within 1 month. Twenty-three other patients, with intervals up to 13 months between studies, were retrospectively identified from medical records. Symptoms, weight, heart rate achieved and peak systolic blood pressure during the 2 studies were similar. Maximal counts circumferential profiles' polar maps were generated and divided into 3 vascular territories. The hypoperfused myocardium was defined as the percent stress profile points below the normal level. The observed values were compared between the 2 studies for each patient. Defect size ranged from 0 to 73%. The concordance correlation coefficient (a measure of the closeness of the data points to the line of identity) and mean absolute deviation were 0.94 and 4.5%, respectively, when all patients were considered together, 0.93 and 3.2%, respectively in the reproducibility group, and 0.94 and 5.1%, respectively, in the retrospective group. Inter- and intraobserver reproducibility were also very high. For individual vessels, the concordance correlation coefficients were all > or = 0.89 and the mean absolute deviations between 3.7 and 9%. Thus, in stable patients with repeat thallium studies within a year, the percent hypoperfused myocardium is highly reproducible.

Adult↗
PubMed1992

Quantitative stress-redistribution thallium-201 SPECT using prone imaging: methodologic development and validation.

Prone 201Tl myocardial perfusion SPECT has been shown to improve left ventricular inferior wall counts compared to supine imaging, thus minimizing diaphragmatic attenuation. Prone SPECT quantitative normal limits were developed and prospectively applied to 36 patients who had coronary angiography. The prone imaging table used had a cut-out under cardiac area which increased the average myocardial counts by 10.7% compared to prone SPECT through the standard table. Overall specificity and sensitivity were 80% and 93%, respectively. For the right, left circumflex and left anterior descending coronary arteries, the specificities were 94%, 71%, and 94%; and sensitivities were 88%, 89% and 78%, respectively. The normalcy rate in 55 normal patients was 89%. Incidence and the severity of patients motion in 200 prone SPECT studies were compared to 200 supine SPECT studies. Mild and severe motion occurred in 12% and 4% of the supine studies and in only 3.5% and none of the prone studies, respectively. When compared to supine SPECT, prone SPECT had higher (p less than 0.01) regional counts/pixel in the inferior wall and septum, but required an average increase of 2.9 +/- 1.0 cm in camera to chest wall distance and resulted in a reduction of total myocardial counts. Prone SPECT provides an alternative approach for patients who cannot tolerate supine imaging. It should be considered when inferior wall defects on supine imaging pose a diagnostic dilemma and when motion on supine imaging necessitates repeat acquisition.

Aged↗
PubMed1991

Incremental prognostic accuracy of clinical, radionuclide and hemodynamic data in acute myocardial infarction.

A logical sequence of testing in evaluating prognosis early in acute myocardial infarction (AMI) would be to use clinical data first, then add noninvasive data and finally add invasive data. The incremental prognostic information concerning 1-year survival obtained from such a sequence in 107 patients with AMI was studied using logistic regression and receiver-operating characteristic curves. Cardiac mortality was 24% at 1 year. Clinical data obtained soon after admission (prior myocardial infarction, heart rate, blood pressure, age) were 78 +/- 5% accurate in the prediction of 1-year survival. The addition of radionuclide-estimated left ventricular ejection fraction or invasive hemodynamic data to the clinical model at this time improved prognostic accuracy to 84 +/- 5% (p = 0.05) and 87 +/- 4% (p = 0.007), respectively. The further addition of invasive data to the model containing clinical and left ventricular ejection fraction data provided a further increment in prognostic accuracy to 89 +/- 4%, whereas no significant increase in accuracy was seen on addition of left ventricular ejection fraction to the model containing clinical and invasive data. It is concluded that clinical data provide important prognostic information concerning late survival early in the course of AMI. This may be improved by the logical application of noninvasive and invasive studies at this time.

Adult↗
PubMed1991

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.

Animals↗
PubMed1991

Prevalence of unsuspected mitral regurgitation and left ventricular diastolic dysfunction in patients with coronary artery disease and acute pulmonary edema associated with normal or depressed left ventricular systolic function.

To define the prevalence and role of left ventricular (LV) systolic dysfunction, LV diastolic dysfunction and mitral regurgitation (MR) in patients with acute pulmonary edema, 40 patients with coronary artery disease and acute pulmonary edema were prospectively evaluated within 36 hours of presentation. LV ejection fraction and 3 parameters of LV diastolic function were measured with radionuclide ventriculography, whereas MR was assessed with Doppler echocardiography. LV ejection fraction was normal in 11 (27%) and depressed in 29 (73%) patients. Moderate or severe MR without LV diastolic dysfunction was common and equally prevalent in patients with and without LV systolic dysfunction (33 vs 38%; difference not significant). Diastolic dysfunction without MR was less frequent but equally prevalent in patients with and without systolic dysfunction (17 vs 27%; difference not significant). Two (18%) of 11 patients without and 12 (33%) of 36 patients with LV systolic dysfunction had both MR and LV diastolic dysfunction. Furthermore, MR was clinically silent and unsuspected in two-thirds of all patients with MR, regardless of a normal or depressed systolic function. These data show that there is a high prevalence of unrecognized moderate to severe MR in patients with acute pulmonary edema, regardless of the presence or absence of LV systolic dysfunction. Furthermore, the prevalence of LV diastolic dysfunction without MR is relatively low even in patients with normal LV systolic function and pulmonary edema. Thus, unrecognized MR may be an important contributor to the syndrome of acute pulmonary edema in patients with normal or depressed LV systolic function.

Aged↗
PubMed1991

Comparison of thallium-201 SPECT and planar imaging methods for quantification of experimental myocardial infarct size.

To compare single photon emission computed tomography (SPECT) and planar thallium-201 (TI-201) myocardial perfusion imaging methods for quantification of left ventricular infarct size, 12 dogs with 6 to 8 hours of closed-chest coronary occlusion and 5 normal dogs were studied. After intravenous administration of TI-201, SPECT and three-view planar images were obtained. After the animals were put to death, hearts were sliced and stained with triphenyltetrazolium chloride (TTC) for planimetric determination of left ventricular infarct size. Infarct size on each SPECT slice and planar image was defined as the percentage of circumferential count profiles falling below the limits derived from normal dogs. Infarct size as a percentage of left ventricular mass was determined from SPECT and planar images before and after correcting for differences in myocardial slice mass from apex to base. The correlation coefficients, the concordance correlation coefficients (reflecting closeness to the line of identity), and the mean absolute deviations of the four methods versus TTC staining were 0.83, 0.77, and 5.1% (SPECT, no correction); 0.85, 0.84, and 3.7% (SPECT with correction); 0.81, 0.42, and 12.9% (planar, no correction); and 0.75, 0.49, and 10.4% (planar with correction). The regression lines did not differ from the line of identity for SPECT, whereas they differed significantly for planar imaging. Thus both SPECT and planar imaging are well suited for quantification of left ventricular infarct size. SPECT, however, appears to be superior to planar imaging, since its regression line more closely approximates the line of identity.

Animals↗
PubMed1991

Frequency of late reversibility in stress-redistribution thallium-201 SPECT using an early reinjection protocol.

To assess the efficacy of an early thallium-201 reinjection protocol for reducing the need for late redistribution imaging, the frequency of thallium-201 late reversibility was prospectively assessed in 62 patients who had stress-redistribution thallium-201 studies by single-photon emission computerized tomography (SPECT), and who received 1 mCi of thallium-201 reinjection immediately following stress tomographic acquisition. These patients also demonstrated greater than or equal to 2 segments with nonreversible defects at 4-hour imaging and underwent late (18-to 72-hour) redistribution imaging. When the criterion of late reversibility was defined as greater than or equal to 1 segment with a 4-hour nonreversible defect demonstrating late reversibility, late reversibility was present in 36 (58%) of the 62 patients and in 88 (24%) of 368 SPECT segments. When the criterion of greater than or equal to 2 segments was used, late reversibility was found in 21 (34%) of the 62 patients and in 73 (20%) of the 368 segments. Of the 21 patients who had greater than or equal to 2 late reversible segments, 12 (57%) exhibited late reversibility in greater than or equal to 3 segments. The frequency of detected reversible defects increased from 32% by 4-hour imaging to 48% by combined 4-hour and late imaging (p less than 0.0001). The patients who demonstrated late reversibility could not be distinguished from those who had only late nonreversible defects by analysis of the clinical, exercise, and electrocardiographic (ECG) variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Technetium 99m sestamibi in the assessment of chronic coronary artery disease.

Extensive work has already been performed with regard to both planar and single photon emission computed (SPECT) technetium 99m sestamibi studies. Before widespread application of optimized acquisition and processing methods, clinical results between 99mTc sestamibi and thallium 201 were remarkably similar. It is anticipated that as techniques for 99mTc sestamibi planar and SPECT imaging become optimized, improvements in sensitivity and specificity for detection of coronary artery disease, over those observed with 201TI, might be forthcoming. This expectation is based on the improved image quality inherent in the use of the 99mTc agent with its higher count rate and higher energy. This improvement in image quality may be a principal reason for laboratories to switch from 201TI to 99mTc sestamibi imaging. It is anticipated that, with improved imaging characteristics, it will be easier for the average community hospital to obtain higher quality planar or SPECT imaging using 99mTc sestamibi rather than 201TI. In addition to improved image quality, the characteristics of 99mTc sestamibi allow gated planar or SPECT perfusion images to be obtained. It has been suggested that stress-gated SPECT sestamibi studies may provide all the information contained in a stress-rest nongated 99mTc sestamibi study, thereby potentially increasing patient throughput, a major concern with SPECT. Throughput can also be increased by using dual-isotope approaches with rest 201TI and stress technetium sestamibi acquisitions, employing either separate or simultaneous imaging with which the entire study can be accomplished in less than 2 hours. With simultaneous dual-isotope acquisition, camera time can be reduced by 50%. Finally, 99mTc sestamibi offers the advantage of the ability to perform first-pass exercise ventricular function and SPECT myocardial perfusion studies with a single injection of tracer. Regarding the assessment of myocardial viability, results to date suggest a very high degree of concordance between 201TI and 99mTc sestamibi studies using either planar or SPECT acquisition techniques. Correlative rest studies with both tracers will be of particular interest, as will preoperative and postoperative and position emission tomography correlation studies.

Aged↗