Effects of regional systolic asynchrony on left ventricular global diastolic function in patients with coronary artery disease

AbstractPatients with coronary artery disease often have impaired left ventricular diastolic filling despite normal global systolic function. The influence of regional systolic asynchrony on diastolic function was assessed by radionuclide angiography in 60 patients with coronary artery disease and normal ejection fraction at rest: group 1 (n = 30) with normal wall motion at rest and group 2 (n = 30) with abnormal wall motion. Data were compared with those obtained from 19 normal volunteers.Age, heart rate, ejection fraction and echocardiographic enddiastolic dimension did not differ among the three groups. Peak filling rate in group 1 and group 2 was similar (2.5 ± 0.5 and 2.3 ± 0.6 end-diastolic counts/s, respectively) and significantly lower than that in the normal subjects (2.8 ± 0.7 end-diastolic counts/s; p < 0.01 vs. group 2, p < 0.05 vs. group 1). Time to peak filling rate was prolonged in group 2 (184 ± 27 ms) compared with that in normal subjects (162 ± 19 ms; p < 0.01) and group 1 (172 ± 15 ms; p < 0.05). Left ventricular end-diastolic pressure was significantly higher in group 2 than in group 1 (14 ± 7 vs. 10 ± 5 mm Hg, respectively; p < 0.05).Asynchrony was assessed by sector analysis of the radionuclide left ventricular region of interest. Diastolic asynchrony was similar in the two patient groups (30 ± 23 ms in group 2, 26 ± 16 ms in group 1) and was higher in both groups than in the normal subjects (16 ± 8 ms; p < 0.61). However, systolic asynchrony was higher in group 2 (32 ± 15 ms) than in both group 1 (14 ± 6 ms; p < 0.01) and the normal group (9 ± 6 ms; p < 0.01). In the total group of patients with coronary artery disease, systolic asynchrony correlated with global time to peak filling rate (r = 0.53; p < 0.001). This correlation became stronger when only group 2 was considered (r = 9.62; p < 0.001). Moreover, in group 2 systolic asynchrony correlated with the duration of the isovolumetric relaxation period (r = 0.58; p < 0.001) and the isovolumetric relaxation period, in turn, correlated with global time to peak filling rate (r = 0.72; p < 0.001).Thus, left ventricular systolic asynchrony affects both the relaxation and filling phases of diastole, thereby contributing to the impairment of diastolic function commonly observed in patients with coronary artery disease

Measurement of myocardial wall thickening from PET/SPECT images: comparison of two methods

Purpose: We compared two methods for measuring myocardial wall thickening from nuclear medicine perfusion scans. The first method uses the percent change in peak activity, and the second method models a profile measured across the myocardium. Method: Mathematical simulations of the myocardium were used. In addition, images with PET or SPECT resolution were created from real MR images. Known amounts of noise were then added. Results: The percent peak thickening (%PT) is nonlinear with true percent thickening, especially for PET resolutions [7 mm full width at half-maximum (FWHM)]. For the peak method, low levels of noise (10%) introduced an error of 8%PT for PET and of 16%PT for SPECT. Additional smoothing reduced these errors. For the fitted model, at 10% noise, the error in thickening was large: 2.3 mm for PET and 7.8 mm for SPECT. Conclusion: The fitted model works well only with good resolution and low noise (e.g., 7 mm FWHM and 10%). The peak method is also sensitive to noise, especially for poorer resolutions. Additional smoothing gives more reliable results for the peak method but not the fitted method. The peak method is therefore the more generally reliable, but even this method may only allow classification of myocardial thickening into broad categories.Publicad

Metabolic evidence of viable myocardium in regions with reduced wall thickness and absent wall thickening in patients with chronic ischemic left ventricular dysfunction

AbstractReduced end-diastolic wall thickness with absent systolic wall thickening has been reported to represent nonviable myocardium in patients with chronic coronary artery disease. To assess whether reduced regional end-diastolic wall thickness and absent wall thickening accurately identify nonviable myocardium, 25 patients with ischemic left ventricular dysfunction (ejection fraction at rest 27 ± 10%) underwent positron emission tomography with oxygen-15-labeled water and 18fluorodeoxyglucose to assess metabolic activity and spin-echo gated nuclear magnetic resonance imaging to measure regional end-diastolic wall thickness and wall thickening. The presence of metabolic activity was defined as 18fluorodeoxyglucose uptake (corrected for partial volume) >50% of that in normal regions.Of 355 myocardial regions evaluated, 266 were hypokinetic or normokinetic at rest and 89 were akinetic (that is, absent wall thickening). 18Fluorodeoxglucose uptake was observed in 97% of the hypokinetic and normokinetic regions and in 74% of the akinetic regions. End-diastolic wall thickness was greater in akinetic regions with than in those without 18fluorodeoxyglucose uptake (11 ± 4 vs. 7 ± 3 nun, p < 0.01). The highest values for sensitivity and specificity of end-diastolic wall thickness in predicting the absence of metabolic activity in akinetic regions were 74% and 79%, respectively, and corresponded to an end-diastolic threshold of 8 mm. However, the positive predictive accuracy was only 55% and did not improve for other end-diastolic wall thickness values. In all myocardial regions, there was only a weak correlation between 18fluorodeoxyglucose activity and either end-diastolic wall thickness (r = 0.17) or wall thickening (r = 0.32).Thus, metabolic activity is present in many regions with reduced end-diastolic wall thickness and absent wall thickening. These data indicate that assessment of regional anatomy and function may be inaccurate in distinguishing asynergic but viable myocardium from nonviable myocardium

Hot spot imaging in cardiovascular diseases:an information statement from SNMMI, ASNC, and EANM

This information statement from the Society of Nuclear Medicine and Molecular Imaging, American Society of Nuclear Cardiology, and European Association of Nuclear Medicine describes the performance, interpretation, and reporting of hot spot imaging in nuclear cardiology. The field of nuclear cardiology has historically focused on cold spot imaging for the interpretation of myocardial ischemia and infarction. Hot spot imaging has been an important part of nuclear medicine, particularly for oncology or infection indications, and the use of hot spot imaging in nuclear cardiology continues to expand. This document focuses on image acquisition and processing, methods of quantification, indications, protocols, and reporting of hot spot imaging. Indications discussed include myocardial viability, myocardial inflammation, device or valve infection, large vessel vasculitis, valve calcification and vulnerable plaques, and cardiac amyloidosis. This document contextualizes the foundations of image quantification and highlights reporting in each indication for the cardiac nuclear imager.</p

Iodofiltic Acid I 123 (BMIPP) Fatty Acid Imaging Improves Initial Diagnosis in Emergency Department Patients With Suspected Acute Coronary Syndromes A Multicenter Trial

ObjectivesThe aim of this study was to assess the performance of β-methyl-p-[123I]-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) to detect acute coronary syndromes (ACS) in emergency department patients with chest pain.BackgroundEmergency department diagnosis of chest pain is problematic, often requiring prolonged observation and stress testing. BMIPP SPECT detects abnormalities in fatty acid metabolism resulting from myocardial ischemia, even many hours after symptom cessation.MethodsEmergency department patients with suspected ACS were enrolled at 50 centers. Patients received 5 mCi BMIPP within 30 h of symptom cessation. BMIPP SPECT images were interpreted semiquantitatively by 3 blinded readers. Initial clinical diagnosis was based on symptoms, initial electrocardiograms, and troponin, whereas the final diagnosis was based on all available data (including angiography and stress SPECT) but not BMIPP SPECT. Final diagnoses were adjudicated by a blinded committee as ACS, intermediate likelihood of ACS, or negative for ACS.ResultsA total of 507 patients were studied and efficacy was evaluated in 448 patients with sufficient data. The sensitivity of BMIPP by 3 blinded readers for a final diagnosis of ACS and intermediate likelihood of ACS was 71% (95% confidence interval [CI]: 64% to 79%), 74% (95% CI: 68% to 81%), and 69% (95% CI: 62% to 77%); the corresponding specificity of BMIPP was 67% (95% CI: 61% to 73%), 54% (95% CI: 48% to 60%), and 70% (95% CI: 64% to 76%). Compared with the initial diagnosis alone, BMIPP + initial diagnosis increased sensitivity from 43% to 81% (p < 0.001), negative predictive value from 62% to 83% (p < 0.001), and positive predictive value from 41% to 58% (p < 0.001), whereas specificity was unchanged (61% to 62%, p = NS).ConclusionsThe addition of BMIPP data to the initially available clinical information adds incremental value toward the early diagnosis of an ACS, potentially allowing determination of the presence or absence of ACS to be made earlier in the evaluation process. (Safety and Efficacy Iodofiltic Acid I 123 in the Treatment of Acute Coronary Syndrome [Zeus-ACS]; NCT00514501