Immunohistochemical-scintigraphic correlation of sympathetic cardiac innervation in postischemic left ventricular aneurysms

BACKGROUND: This study was conceived to explore the correspondence between scintigraphic imaging of the sympathetic innervation of human postischemic left ventricular aneurysms and direct immunohistochemical localization of the nerve fibers in the same area. MATERIALS AND METHODS: In 7 patients undergoing left ventricular aneurysmectomy for postischemic ventricular aneurysm, the findings of thallium 201 and metaiodobenzylguanidine myocardial scintigraphy were compared with direct immunohistochemical localization of the nerve fibers in the same area. This comparison showed good correspondence between scintigraphic and immunohistochemical data, although scintigraphy failed to detect areas of minimal sympathetic innervation. Moreover, microscopic analysis showed sympathetic nerve fibers with peculiar morphology and distribution in the aneurysmal zone. CONCLUSION: There is a good correspondence between immunohistochemical and scintigraphic imaging in the detection of sympathetic cardiac nerves in human left ventricular aneurysms; a morphologically abnormal sympathetic reinnervation can be found in the aneurysmal area (although denervation can persist in some zones).     

Factor analysis of multigated cardiac blood pool scintigram for the measurement of left ventricular ejection fraction

Left ventricular ejection fraction (EF) was measured by factor analysis (FA) of multigated cardiac blood pool scintigram in 38 consecutive patients, and compared with that measured by the variable ROI method (EFVROI) with automated left ventricular contour detection. FA was automatically performed without operator intervention with a success rate of 100%. The correlation of EF with EFVROI was significant in the group of 22 patients with normal wall motion (r = 0.65, p less than 0.001), and the entire group of patients (r = 0.70, p less than 0.001), but not significant (p = 0.19) in the group of 16 patients with abnormal wall motion. In conclusion, left ventricular ejection fraction can be estimated by factor analysis of MUGA in patients with normal wall motion.     

Comparison of three semiautomatic methods for determination of left ventricular ejection fraction from gated cardiac blood pool images

A number of computer programs exist for the determination of ejection fraction from gated blood pool images. Three commercially available algorithms were compared on the same radionuclide data from 50 catheterized patients. The methods used were: (1) simple thresholding, (2) second derivative edge determination, and (3) a combination of these two. There was good correlation with catheterization ejection fraction for all three methods using smoothed data [r=0.781, 0.77, 0.84 respectively (P<0.01)]. However, interobserver variance was significantly decreased (P<0.01) by use of the second derivative method when compared with the other two methods and catheterization. Thus, if accuracy and low interobserver variance are required, then a combination of a second derivative and thresholding method is preferable.     

Regional observer performance variation in the evaluation of gated cardiac blood pool studies

Receiver operating characteristic (ROC) analysis demonstrated that regional variations of sensitivity exist in the detection of wall motion abnormality in cardiac blood pool imaging studies. The observer response is significantly better in the apex than either the septum or posterolateral wall segments. The observer errors tend to be false-negative in the posterolateral wall segment and false-positive in the other two segments. Image presentation can make a significant difference to the overall sensitivity, and the monochrome cine-sequence performed best in this study.     

Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR

Objective:

Obtaining new details of radial motion of left ventricular (LV) segments using velocity-encoding cardiac MRI.

Methods:

Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Cine images for navigator-gated phase contrast velocity mapping were acquired using a black blood segmented κ-space spoiled gradient echo sequence with a temporal resolution of 13.8 ms. Peak systolic and diastolic radial velocities as well as radial velocity curves were obtained for 16 ventricular segments.

Results:

Significant differences among peak radial velocities of basal and mid-ventricular segments have been recorded. Particular patterns of segmental radial velocity curves were also noted. An additional wave of outward radial movement during the phase of rapid ventricular filling, corresponding to the expected timing of the third heart sound, appeared of particular interest.

Conclusion:

The technique has allowed visualization of new details of LV radial wall motion. In particular, higher peak systolic radial velocities of anterior and inferior segments are suggestive of a relatively higher dynamics of anteroposterior vs lateral radial motion in systole. Specific patterns of radial motion of other LV segments may provide additional insights into LV mechanics.

Advances in knowledge:

The outward radial movement of LV segments impacted by the blood flow during rapid ventricular filling provides a potential substrate for the third heart sound. A biphasic radial expansion of the basal anteroseptal segment in early diastole is likely to be related to the simultaneous longitudinal LV displacement by the stretched great vessels following repolarization and their close apposition to this segment.Advances in cardiac imaging techniques have allowed evaluation of new details of the complex pattern of left ventricular (LV) motion. Using high temporal resolution cardiovascular MR with myocardial velocity-encoding techniques, we previously performed a detailed analysis of rotational and longitudinal motions of the left ventricle, correlating them with the orientation or cardiomyocyte aggregates within the LV wall.^1,2 However, accurate evaluation of radial motion is equally important. For example, radial wall motion abnormalities have been detected in patients with diabetes³ and hypertrophic cardiomyopathy,⁴ whereas radial dyssynchrony is almost universal in patients with heart failure.⁵ The purpose of this study was to obtain new details of global and regional radial wall motion of the left ventricle using the cardiac MR high temporal resolution myocardial velocity-encoding technique.^6,7 Considering recent interest in myocardial multilayer measurements, which provide more layer-specific information about the functional state of the myocardium at different levels,^8–13 separate calculations of all myocardial velocities and their corresponding peak times for the inner (endocardial), middle (transmural) and outer (epicardial) layers of the LV wall were performed.     

Successful surgical removal of a cardiac myxoma from the left ventricular outflow tract

The precondition for successful, exclusively surgical treatment in the extracorporeal circulation, is the precise diagnosis of heart myxoma, particularly in rare locations such as the left ventricle. We present a case of myxoma in the outflow tract of the left ventricle as the exceptionally rare location, successfully diagnosed and surgically treated at the Clinic for Cardiac and Thoracic Surgery of the Military Medical Academy. A female patient, aged 46 years, was sent from another hospital with misdiagnosis of idiopathic hypertrophic subaortic stenosis. The patient was successfully operated after transthoracic and transesophageal echocardiography as the main diagnostic procedures. Myxoma that completely obstructed the aortic opening if pulled, was completely removed through aortic valve in the extracorporeal circulation. Its pedicle was arising from the ventricular side of the great mitral cusp. Postoperative course was uneventful and the patient was released from the hospital on the tenth postoperative day.     

Regional observer performance variation in the evaluation of gated cardiac blood pool studies.

Receiver operating characteristic (ROC) analysis demonstrated that regional variations of sensitivity exist in the detection of wall motion abnormality in cardiac blood pool imaging studies. The observer response is significantly better in the apex than either the septum or posterolateral wall segments. The observer errors tend to be false-negative in the posterolateral wall segment and false-positive in the other two segments. Image presentation can make a significant difference to the overall sensitivity, and the monochrome cine-sequence performed best in this study.     

Lack of correlation between ventricular late potentials and left ventricular mass in top-level male athletes

PURPOSE: The aim of this study was to establish: 1) the prevalence of abnormal signal-averaged electrocardiogram (SAECG) in a large population of top-level athletes and 2) the relationship between SAECG parameters and left ventricular mass. One-hundred and fifty-three elite male athletes without apparent heart disease, symptoms, or arrhythmias were studied. METHODS: Fifty-six athletes (37%) had increased left ventricular mass (> 134 g.m(-2)). All athletes underwent time-domain SAECG on 300-400 heart beats recorded at rest from three bipolar orthogonal tests with a filter setting of 40-250 Hz. Criteria for abnormality were 1) filtered QRS duration > 114 ms, 2) duration of low-amplitude signals > 38 ms, or 3) root mean square voltage of the last 40 ms of the filtered QRS < 20 microV. RESULTS: The prevalence of abnormal SAECG was 7.2% (abnormality of one parameter), 6.5% (abnormality of two parameters), and 5.8%(abnormality of three parameters). The prevalence of abnormal SAECG was similar in athletes with or without increased left ventricular mass. CONCLUSIONS: In conclusion, this study showed: 1) the low rate of positive results of SAECG parameters in top-level male athletes, similar to that found in healthy sedentary subjects; and 2) the lack of correlation between left ventricular mass and overall SAECG parameters.     

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.     

Quantitative analysis of cardiac left ventricular variables obtained by MRI at 3 T: a pre- and post-contrast comparison

Short-axis cine images are acquired during cardiac MRI in order to determine variables of cardiac left ventricular (LV) function such as ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and LV mass. In cardiac perfusion assessments this imaging can be performed in the temporal window between first pass perfusion and the acquisition of delayed enhancement images in order to minimise overall scanning time. The objective of this study was to compare pre- and post-contrast short-axis LV variables of 15 healthy volunteers using a two-dimensional cardiac-gated segmented cine true fast imaging with steady state precession sequence and a 3.0 T MRI unit in order to determine the possible effects of contrast agent on the calculated cardiac function variables. Image analysis was carried out using semi-automated software. The calculated mean LV mass was lower when derived from the post-contrast images, relative to those derived pre-contrast (102 vs 108.1 g, p<0.0001). Small but systematic significant differences were also found between the mean pre- and post-contrast values of EF (69.4% vs 68.7%, p<0.05), EDV (142.4 vs 143.7 ml, p<0.05) and ESV (44.2 vs 45.5 ml, p<0.005), but no significant differences in SV were identified. This study has highlighted that contrast agent delivery can influence the numerical outcome of cardiac variables calculated from MRI and this was particularly noticeable for LV mass. This may have important implications for the correct interpretation of patient data in clinical studies where post-contrast images are used to calculate LV variables, since LV normal ranges have been traditionally derived from pre-contrast data sets.     

Multislice cardiac spiral CT evaluation of atypical hypertrophic cardiomyopathy with a calcified left ventricular thrombus

We report a case of a 43-year-old male patient with an atypical nonobstructive hypertrophic cardiomyopathy and a calcified left ventricular thrombus, and present results of multislice computed tomography (MSCT) using retrospective electrocardiograph gating, which is a new modality in cardiac imaging. Obtaining virtually motion-free images with a temporal resolution of 250 ms in an optimized heart scan MSCT allows functional imaging with evaluation of impaired systolic and diastolic left ventricular wall motion.     

Quantitative analysis of left ventricular performance from sequences of cardiac magnetic resonance imaging using active mesh model

In this study, the local and global left ventricular function are estimated by fitting three-dimensional active mesh model (3D-AMM) to the initial sparse displacement which is measured from an establishing point correspondence procedure. To evaluate the performance of the algorithm, eight image sequences were used and the results were compared with those reported by other researchers. The findings were consistent with previously published values and the clinical evidence as well. The results demonstrated the superiority of the novel strategy with respect to formerly presented algorithm reported by author et al. Furthermore, the results are comparable to the current state-of-the-art methods.     

Clinical usefulness of ultrashort-lived iridium-191m from a carbon-based generator system for the evaluation of the left ventricular function

Ultrashort-lived 191mIr (4.96 sec; 63-74 and 129 keV photons) is potentially advantageous for first-pass radionuclide angiocardiography, offering the opportunity to perform repeat studies with very low absorbed radiation dose to the patient. Left ventricular (LV) first-pass studies were performed in 72 patients with 191mIr from a new bedside 1.3 Ci (48.1 GBq) 191Os/191mIr generator system using an activated carbon support that offers high 191mIr yields (15-18%) and consistent low 191Os breakthrough (2-4 x 10(-4)%/bolus). Using a single crystal digital gamma camera, uncorrected end-diastolic counts in the left ventricular representative cycle ranged from 10 up to 30 k counts. The reproducibility of repeated LV ejection fraction (LVEF) determination at 2-min intervals in 50 patients was r = 0.97, mean diff. = 2.08 +/- 1.55 EF units. Comparison between 191mIr (80-120 mCi; 2,960-4,400 MBq) and 99mTc (20-25 mCi; 750-925 MBq) LV count rates indicates a 3 wk useful shelf life of this new generator system for cardiac studies. Iridium-191m determined LVEF correlated closely with 99mTc determined LVEF in 32 patients (r = 0.96, mean diff. = 1.87 +/- 1.23 EF units). Parametric images for LV wall motion analysis were comparable with both isotopes. We conclude that rapid, repeat, and reproducible high count rate first-pass left ventricular studies can be obtained with 191mIr from this new 191Os/191mIr generator system using a single crystal digital gamma camera.     

Comparison of contemporaneous left ventricular ejection fraction (LVEF) obtained from planar gated cardiac blood pool scans (GCBPS) and Tl-201 gated myocardial perfusion scans (MPS) using a novel solid state dedicated cardiac camera

Background

There is limited data on the concordance of left ventricular ejection fraction (LVEF) obtained via solid state dedicated cardiac cameras (SSD) and gated cardiac blood pool scans (GCBPS). This study aimed to examine the agreement of LVEF measured during GCBPS and Tl-201 myocardial perfusion scans (MPS) using SSD.

Methods

Seventy six patients were enrolled. Following stress MPS with 0.8 Mbq/kg (0.022 mCi/kg) Tl-201 and 8-frame gated rest studies after additional 15 Mbq (0.41 mCi) Tl-201, LVEFs were obtained using ECToolbox (ECT) and quantitative gated SPECT (QGS) software. Same day 16-frame planar GCBPS were performed. Interobserver variability was compared and LVEF results were compared using paired t tests, Pearson’s correlation and the differences of the LVEF were plotted against GCBPS values.

Results

For GCBPS, ECT and QGS, the mean (±SD) LVEF was 52% ± 14%, 61% ± 18% and 48% ± 19%, respectively. When compared to GCBPS, ECT and QGS, LVEFs had similar R values of 0.85 and 0.83, respectively, and mean differences [95% limits of agreement (LA)] of ?8.6% (?27.4% to +10.2%, P < .001) and 4.2% (?17.2% to +25.6%, P = .001), respectively.

Conclusion

While the LVEF obtained by ECT or QGS demonstrates a statistically significant correlation with GCBPS, they are significantly different and the wide 95% LA suggest that Tl-201 MPS LVEFs derived from either software package are not interchangeable with GCBPS results.     

Comparison of left ventricular functional parameters obtained from three different commercial automated software cardiac quantification program packages and their intraobserver reproducibility

Objective  

ECG-gated myocardial perfusion scintigraphy (MPS) can be used to determine several cardiac functional parameters (e.g., left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV)). In this study, we aimed to compare these cardiac functional parameters calculated by the following cardiac quantification programs: Emory Cardiac Toolbox (ECTb), Quantitative Gated SPECT (QGS), and Myometrix. We also evaluated reproducibility of the cardiac programs.     

冠状动脉SYNTAX评分与左心功能指数间相关性研究

目的 分析冠心病患者冠状动脉病变复杂程度与左心功能指数间的相关性.方法 69例冠心病患者根据冠状动脉CT血管成像(CTA) SYNTAX评分分为低危组(27例)、中危组(23例)、高危组(19例).使用SPSS16软件,采用ANOVA分析比较3组左心功能的差异,采用Spearman秩相关分析SYNTAX评分与左心功能指标间的相关性.结果 低、中、高危3组患者间左心室舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)、射血分数(EF)、心肌质量(MM)差异有统计学意义(F值分别为7.254、9.181、13.004、7.544、5.276,P均<0.05).冠状动脉SYNTAX评分与左心室EF呈显著负相关(r=-0.702,P<0.05),与MM呈显著正相关(r=0.638,P<0.05).结论 冠状动脉SYNTAX评分与左心室EF呈显著负相关,与左心室MM呈显著正相关.