Parametric quantification of myocardial ischemia using real-time perfusion adenosine stress echocardiography images. A comparison with SPECT (original) (raw)
Related papers
Clinical Physiology and Functional Imaging, 2010
Background: Real-time perfusion (RTP) adenosine stress echocardiography (ASE) can be used to visually evaluate myocardial ischaemia. The RTP power modulation technique, provides images for off-line parametric perfusion quantification using Qontrast Ò software. From replenishment curves, this generates parametric images of peak signal intensity (A), myocardial blood flow velocity (b) and myocardial blood flow (Axb) at rest and stress. This may be a tool for objective myocardial ischaemia evaluation. We assessed myocardial ischaemia by RTP-ASE Qontrast Ò-generated images, using 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) as reference. Methods: Sixty-seven patients admitted to SPECT underwent RTP-ASE (SONOS 5500) during Sonovue Ò infusion, before and throughout adenosine stress, also used for SPECT. Quantitative off-line analyses of myocardial perfusion by RTP-ASE Qontrast Ò-generated A, b and Axb images, at different time points during rest and stress, were blindly compared to SPECT. Results: We analysed 201 coronary territories [corresponding to the left anterior descendent (LAD), left circumflex (LCx) and right coronary (RCA) arteries] from 67 patients. SPECT showed ischaemia in 18 patients. Receiver operator characteristics and kappa values showed that A, b and Axb image interpretation significantly identified ischaemia in all territories (area under the curve 0AE66-0AE80, P = 0AE001-0AE05). Combined A, b and Axb image interpretation gave the best results and the closest agreement was seen in the LAD territory: 89% accuracy; kappa 0AE63; P<0AE001. Conclusion: Myocardial isachemia can be evaluated in the LAD territory using RTP-ASE Qontrast Ò-generated images, especially by combined A, b and Axb image interpretation. However, the technique needs improvements regarding the LCx and RCA territories.
Quantitative detection of myocardial ischaemia by stress echocardiography; a comparison with SPECT
Cardiovascular Ultrasound, 2009
Aims: Real-time perfusion (RTP) adenosine stress echocardiography (ASE) can be used to visually evaluate myocardial ischaemia. The RTP power modulation technique angio-mode (AM), provides images for off-line perfusion quantification using Qontrast ® software, generating values of peak signal intensity (A), myocardial blood flow velocity (β) and myocardial blood flow (Axβ). By comparing rest and stress values, their respective reserve values (A-r, β-r, Axβ-r) are generated. We evaluated myocardial ischaemia by RTP-ASE Qontrast ® quantification, compared to visual perfusion evaluation with 99m Tc-tetrofosmin singlephoton emission computed tomography (SPECT). Methods and Results: Patients admitted to SPECT underwent RTP-ASE (SONOS 5500) using AM during Sonovue ® infusion, before and throughout adenosine stress, also used for SPECT. Visual myocardial perfusion and wall motion analysis, and Qontrast ® quantification, were blindly compared to one another and to SPECT, at different time points off-line. We analyzed 201 coronary territories (left anterior descendent [LAD], left circumflex [LCx] and right coronary [RCA] artery territories) in 67 patients. SPECT showed ischaemia in 18 patients and 19 territories. Receiver operator characteristics and kappa values showed significant agreement with SPECT only for β-r and Axβ-r in all segments: area under the curve 0.678 and 0.665; P < 0.001 and < 0.01, respectively. The closest agreements were seen in the LAD territory: kappa 0.442 for both β-r and Axβr; P < 0.01. Visual evaluation of ischaemia showed good agreement with SPECT: accuracy 93%; kappa 0.67; P < 0.001; without non-interpretable territories. Conclusion: In this agreement study with SPECT, RTP-ASE Qontrast ® quantification of myocardial ischaemia was less accurate and less feasible than visual evaluation and needs further development to be clinically useful.
European Journal of Nuclear Medicine and Molecular Imaging, 2013
Purpose Automated software tools have permitted more comprehensive, robust and reproducible quantification of coronary stenosis, plaque burden and plaque location of coronary computed tomography angiography (CTA) data. The association between these quantitative CTA (QCT) parameters and the presence of myocardial ischaemia has not been explored. The aim of the present investigation was to evaluate the association between QCT parameters of coronary artery lesions and the presence of myocardial ischaemia on gated myocardial perfusion single-photon emission CT (SPECT). Methods Included in the study were 40 patients (mean age 58.2±10.9 years, 27 men) with known or suspected coronary artery disease (CAD) who had undergone multidetector row CTA and gated myocardial perfusion SPECT within 6 months. From the CTA datasets, vessel-based and lesionbased visual analyses were performed. Consecutively, lesion-based QCT was performed to assess plaque length, plaque burden, percentage lumen area stenosis and remodelling index. Subsequently, the presence of myocardial ischaemia was assessed using the summed difference score (SDS ≥2) on gated myocardial perfusion SPECT. Results Myocardial ischaemia was seen in 25 patients (62.5 %) in 37 vascular territories. Quantitatively assessed significant stenosis and quantitatively assessed lesion length were independently associated with myocardial ischaemia (OR 7.72, 95 % CI 2.41-24.7, p<0.001, and OR 1.07, 95 % CI 1.00-1.45, p=0.032, respectively) after correcting for clinical variables and visually assessed significant stenosis. The addition of quantitatively assessed significant stenosis (χ 2 =20.7) and lesion length (χ 2 =26.0) to the clinical variables and the visual assessment (χ 2 =5.9) had incremental value in the association with myocardial ischaemia. Conclusion Coronary lesion length and quantitatively assessed significant stenosis were independently associated with myocardial ischaemia. Both quantitative parameters have incremental value over baseline variables and visually assessed significant stenosis. Potentially, QCT can refine assessment of CAD, which may be of potential use for identification of patients with myocardial ischaemia. Michiel A. de Graaf and Heba M. El-Naggar share first authorship.
Heart, 2005
Objective: To evaluate whether myocardial parametric imaging (MPI) is superior to visual assessment for the evaluation of myocardial viability. Methods and results: Myocardial contrast echocardiography (MCE) was assessed in 11 pigs before, during, and after left anterior descending coronary artery occlusion and in 32 patients with ischaemic heart disease by using intravenous SonoVue administration. In experimental studies perfusion defect area assessment by MPI was compared with visually guided perfusion defect planimetry. Histological assessment of necrotic tissue was the standard reference. In clinical studies viability was assessed on a segmental level by (1) visual analysis of myocardial opacification; (2) quantitative estimation of myocardial blood flow in regions of interest; and (3) MPI. Functional recovery between three and six months after revascularisation was the standard reference. In experimental studies, compared with visually guided perfusion defect planimetry, planimetric assessment of infarct size by MPI correlated more significantly with histology (r 2 = 0.92 versus r 2 = 0.56) and had a lower intraobserver variability (4% v 15%, p , 0.05). In clinical studies, MPI had higher specificity (66% v 43%, p , 0.05) than visual MCE and good accuracy (81%) for viability detection. It was less time consuming (3.4 (1.6) v 9.2 (2.4) minutes per image, p , 0.05) than quantitative blood flow estimation by regions of interest and increased the agreement between observers interpreting myocardial perfusion (k = 0.87 v k = 0.75, p , 0.05). Conclusion: MPI is useful for the evaluation of myocardial viability both in animals and in patients. It is less time consuming than quantification analysis by regions of interest and less observer dependent than visual analysis. Thus, strategies incorporating this technique may be valuable for the evaluation of myocardial viability in clinical routine. M yocardial contrast echocardiography (MCE) has provided new insight into the assessment of myocardial viability in acute ischaemic syndromes 1 2 and in stable ischaemic heart disease. 3 4 However, clinical assessment of myocardial viability by MCE is based on visual interpretation of MCE images or on quantitative computer assisted processing. Visual interpretation of myocardial perfusion is subjective and requires experienced investigators. 3-7 Quantitative analysis of myocardial perfusion by using replenishment kinetics to fit exponential curves is, on the other hand, time consuming and provides low spatial resolution. Myocardial parametric imaging (MPI) is a new method that provides automated colour coded quantification of myocardial blood flow and parametric imaging according to the relative degree of perfusion. 8-9 Myocardial parametric quantification to detect inducible ischaemia has been shown to be feasible. 8 9 However, the value of MPI for myocardial viability assessment has not been reported. The purpose of this study was to assess the value of MPI for viability detection in the experimental setting of acute infarction and in patients with stable ischaemic heart disease.
2017
The standard assessment of myocardial perfusion has several limitations since it is mainly based on its relative distribution. In the clinical practice, the evaluation of perfusion by using Computed Tomography (CT) Imaging is usually performed visually or semi-quantitatively. The scarcity of quantitative perfusion data not always allows a proper diagnose of patients which are suspected of suffering from some diseases, such as Ischemic Heart Disease (IHD). This project aims to develop a clinical tool for the automatic quantification of myocardial perfusion in patients with suspected IHD. Myocardial perfusion is assessed based on a combined diagnosis protocol (CT/CTP protocol) which involves the acquisition of two contrast-enhanced CT images, one obtained at rest and another acquired under pharmacological stress. All perfusion images are evaluated in the short-axis view of the left ventricle (basal, medium and apical slices), divided in different segments according to the 16-AHA-segmentation model and divided circumferentially in two layers with the same thickness to define subendocardium and subepicardium. The clinical tool, which is developed with MATLAB, enables the automatic quantification of perfusion in each myocardial segment by providing the mean of Hounsfield Units in those regions. Based on this analysis the clinicians can compared the values at baseline and at hyperemia, and they can better determine hypoperfusion defects in patients with IHD. The validation of the clinical tool is performed by comparing automatic and manual perfusion measurements of 10 patients with suspected IHD who were previously assessed with Single Photon Emission Computed Tomography (SPECT) for perfusion analysis. A strong linear correlation is found between the automatic and manual results. Afterwards, perfusion defects obtained from CT/CTP protocol are compared to perfusion defects from SPECT, to assess the applicability of this clinical tool for the diagnosis of IHD. Sensitivity, specificity, positive predictive value and negative predictive values of CT/CTP protocol are 0.64, 0.36, 0.48 and 0.88, respectively. Results from these measurements are not quite good. Nonetheless, the analysis should be done increasing the number of patients to have a better assessment of this protocol for the diagnosis of this disease.