Sandra Hamada

First fusion and combined evaluation of 3D-CMR perfusion with 3D-MR coronary angiography

Introduction Myocardial perfusion and the status of the coronary arteries are the two major parameters for the characterization of coronary artery disease (CAD) and for guiding therapeutical interventions. It has been shown that hybrid imaging strategies to acquire both parameters such as SPECT with CT-angiography provide an added value for clinical decision making in the treatment of CAD[1]. Thus the 2014 ESC Guidelines for the first time recommend hybrid imaging for planning myocardial revascularization[2]. However, SPECT and CT expose the patient to ionizing radiation and, in large prospective trials, SPECT showed inferior sensitivity to detect CAD when compared with CMR-perfusion[3]. Therefore, the aim of this study was to investigate the feasibility and potential added value of MR-based hybrid imaging by the combined assessment and fusion of 3D-MR coronary angiography (MRCA) with a 3D-CMR perfusion sequence.

Analysis of spatiotemporal fidelity in quantitative 3D first-pass perfusion cardiovascular magnetic resonance

BackgroundWhole-heart first-pass perfusion cardiovascular magnetic resonance (CMR) relies on highly accelerated image acquisition. The influence of undersampling on myocardial blood flow (MBF) quantification has not been systematically investigated yet. In the present work, the effect of spatiotemporal scan acceleration on image reconstruction accuracy and MBF error was studied using a numerical phantom and validated in-vivo.MethodsUp to 10-fold scan acceleration using k-t PCA and k-t SPARSE-SENSE was simulated using the MRXCAT CMR numerical phantom framework. Image reconstruction results were compared to ground truth data in the k-f domain by means of modulation transfer function (MTF) analysis. In the x-t domain, errors pertaining to specific features of signal intensity-time curves and MBF values derived using Fermi model deconvolution were analysed. In-vivo first-pass CMR data were acquired in ten healthy volunteers using a dual-sequence approach assessing the arterial input function (AIF) and myocardial enhancement. 10x accelerated 3D k-t PCA and k-t SPARSE-SENSE were compared and related to non-accelerated 2D reference images.ResultsMTF analysis revealed good recovery of data upon k-t PCA reconstruction at 10x undersampling with some attenuation of higher temporal frequencies. For 10x k-t SPARSE-SENSE the MTF was found to decrease to zero at high spatial frequencies for all temporal frequencies indicating a loss in spatial resolution. Signal intensity-time curve errors were most prominent in AIFs from 10x k-t PCA, thereby emphasizing the need for separate AIF acquisition using a dual-sequence approach. These findings were confirmed by MBF estimation based on AIFs from fully sampled and undersampled simulations. Average in-vivo MBF estimates were in good agreement between both accelerated and the fully sampled methods. Intra-volunteer MBF variation for fully sampled 2D scans was lower compared to 10x k-t PCA and k-t SPARSE-SENSE data.ConclusionQuantification of highly undersampled 3D first-pass perfusion CMR yields accurate MBF estimates provided the AIF is obtained using fully sampled or moderately undersampled scans as part of a dual-sequence approach. However, relative to fully sampled 2D perfusion imaging, intra-volunteer variation is increased using 3D approaches prompting for further developments.

Fusion of CT coronary angiography and whole-heart dynamic 3D cardiac MR perfusion: building a framework for comprehensive cardiac imaging

The purpose of this work was to develop a framework for 3D fusion of CT coronary angiography (CTCA) and whole-heart dynamic 3D cardiac magnetic resonance perfusion (3D-CMR-Perf) image data—correlating coronary artery stenoses to stress-induced myocardial perfusion deficits for the assessment of coronary artery disease (CAD). Twenty-three patients who underwent CTCA and 3D-CMR-Perf for various indications were included retrospectively. For CTCA, image quality and coronary diameter stenoses >u200950% were documented. For 3D-CMR-Perf, image quality and stress-induced perfusion deficits were noted. A software framework was developed to allow for 3D image fusion of both datasets. Computation steps included: (1) fully automated segmentation of coronary arteries and heart contours from CT; (2) manual segmentation of the left ventricle in 3D-CMR-Perf images; (3) semi-automatic co-registration of CT/CMR datasets; (4) projection of the 3D-CMR-Perf values on the CT left ventricle. 3D fusion analysis was compared to separate inspection of CTCA and 3D-CMR-Perf data. CT and CMR scans resulted in anxa0image quality being rated as good to excellent (mean scores 3.5u2009±u20090.5 and 3.7u2009±u20090.4, respectively, scale 1–4). 3D-fusion was feasible in all 23 patients, and perfusion deficits could be correlated to culprit coronary lesions in all but one case (22/23u2009=u200996%). Compared to separate analysis of CT and CMR data, coronary supply territories of 3D-CMR-Perf perfusion deficits were refined in two cases (2/23u2009=u20099%), and the relevance of stenoses in CTCA was re-judged in four cases (4/23u2009=u200917%). In conclusion,xa03D fusion of CTCA/3D-CMR-Perf facilitates anatomic correlation of coronary lesions and stress-induced myocardial perfusion deficits thereby helping to refine diagnostic assessment of CAD.

3D fusion of coronary CT angiography and CT myocardial perfusion imaging: Intuitive assessment of morphology and function

BACKGROUNDnThe objective of this work was to support three-dimensional fusion of coronary CT angiography (coronary CTA) and CT myocardial perfusion (CT-Perf) data visualizing coronary artery stenoses and corresponding stress-induced myocardial perfusion deficits for diagnostics of coronary artery disease.nnnMETHODSnTwelve patients undergoing coronary CTA/CT-Perf after heart transplantation were included (56xa0±xa012 years, all males). CT image quality was rated. Coronary diameter stenoses >50% were documented for coronary CTA. Stress-induced perfusion deficits were noted for CT-Perf. A software was implemented facilitating 3D fusion imaging of coronary CTA/CT-Perf data. Coronary arteries and heart contours were segmented automatically. To overcome anatomical mismatch of coronary CTA/CT-Perf image acquisition, perfusion values were projected on the left ventricle as visualized in coronary CTA. Three resulting datasets (coronary tree/heart contour/perfusion values) were fused for combined three-dimensional rendering. 3D fusion was compared with conventional analysis of coronary CTA/CT-Perf data and to results from catheter coronary angiography.nnnRESULTSnCT image quality was rated good-excellent (3.5xa0±xa00.5, scale 1-4). 3D fusion imaging of coronary CTA/CT-Perf data was feasible in 11/12 patients (92%). One patient (8%) was excluded from further analysis due to severe motion artifacts. 2 of 11 remaining patients (18%) showed both stress-induced perfusion deficits and relevant coronary stenoses. Using 3D fusion imaging, the ischemic region could be correlated to a culprit coronary lesion in one case (1/2xa0=xa050%) and diagnostic findings could be rectified in the other case (1/2xa0=xa050%). Coronary CTA was in full correspondence with catheter coronary angiography.nnnCONCLUSIONnA method for 3D fusion of coronary CTA/CT-Perf is introduced correlating relevant coronary lesions and corresponding stress-induced myocardial perfusion deficits.

Multi-centre study of whole-heart dynamic 3D cardiac magnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: gender based analysis of diagnostic performance

AimsnCoronary artery disease (CAD) is a leading cause of morbidity and mortality in women and non-invasive testing for CAD in women can be more challenging than in men. This study compared the diagnostic performance of whole-heart dynamic 3D cardiovascular magnetic resonance (CMR) stress perfusion imaging in female and male patients with quantitative coronary angiography (QCA) and fractional flow reserve (FFR) as reference tests.nnnMethods and resultsnFour hundred sixteen patients with suspected or known CAD were enrolled in five European centres. CMR imaging was performed prior to clinically indicated coronary angiography. QCA was performed in all patients and FFR in 357 of 416 patients. Whole-heart dynamic 3D CMR first-pass perfusion imaging was conducted at rest and during adenosine stress. All CMR analyses were operated by experienced investigators blinded to all clinical data. One hundred nineteen female and 297 male patients were included and successfully examined (mean age 65u2009±u200911 and 63u2009±u200911u2009years, respectively). FFR was performed in 106 female and 251 male patients. Sensitivity and specificity of whole-heart dynamic 3D CMR stress perfusion imaging were 89% (95% CI: 77-96) and 82% (95% CI: 70-90) in the female population and 83% (95% CI: 77-86) and 79% (95% CI: 71-86) in the male population relative to QCA (Pu2009=u20090.474 and Pu2009=u20090.83, P-values for comparison between genders). Sensitivity and specificity were 95% (95% CI: 82-99) and 84% (95% CI: 73-92) in the female population and 83% (95% CI: 76-89) and 82% (95% CI: 74-88) in the male population when using FFR as the reference (Pu2009=u20090.134 and Pu2009=u20090.936, P-values for comparison between genders). Diagnostic accuracy in females was 92% (95% CI: 85-96) and 86% (95% CI: 81-90) in males when using FFR as the reference. The prevalence of CAD as defined by FFR (<0.8) was 36% in females and 53% in males.nnnConclusionnWhole-heart dynamic 3D CMR stress perfusion imaging has a high diagnostic accuracy for the detection of significant CAD irrespective of gender and is therefore a suitable non-invasive testing tool to detect myocardial ischaemia in both genders.

Comprehensive morphologic and functional imaging of heart transplant patients: first experience with dynamic perfusion CT

ObjectivesWe aimed to assess the diagnostic performance of a combined protocol with coronary computed tomography angiography (CCTA) and stress CT perfusion imaging (CTP) in heart transplant patients for comprehensive morphological and functional imaging.MethodsIn this prospective study, 13 patients undergoing routine follow-up 8±6 years after heart transplantation underwent CCTA and dynamic adenosine stress CTP using a third-generation dual-source CT scanner, cardiac magnetic resonance (MR) adenosine stress perfusion imaging at 1.5 T, and catheter coronary angiography. In CCTA stenoses >50% luminal diameter narrowing were noted. Myocardial perfusion deficits were documented in CTP and MR. Quantitative myocardial blood flow (MBF) was calculated with CTP. Left ventricular ejection fraction was determined on cardiac MR cine images. Radiation doses of CT were determined.ResultsOne of the 13 patients had to be excluded because of severe motion artifacts. CCTA identified three patients with stenosis >50%, which were confirmed with catheter coronary angiography. CTP showed four patients with stress-induced myocardial hypoperfusion, which were confirmed by MR stress perfusion imaging. Quantitative analysis of global MBF showed lower mean values as compared to known reference values (MBF under stress 125.5 ± 34.5 ml/100 ml/min). Average left ventricular ejection fraction was preserved (56 ± 5%).ConclusionsIn heart transplant patients, a comprehensive CT protocol for the assessment of morphology and function including CCTA and CTP showed good concordance to results from MR perfusion imaging and catheter coronary angiography.Key Points• Stress CT perfusion imaging enables the detection of myocardial ischemia• CT myocardial perfusion imaging can be combined with coronary computed tomography angiography• Combining perfusion and coronary CT imaging is accurate in heart transplant patients• CT myocardial perfusion imaging can be performed at a reasonable radiation dose

Impact of stroke volume assessment by integrating multi-detector computed tomography and Doppler data on the classification of aortic stenosis

BACKGROUNDnThe prevalence of low flow low gradient (LFLG) severe aortic stenosis (AS) may be overrated due to underestimation of stroke volume in two-dimensional (2D) echocardiography. The implications of 3D imaging on stroke volume calculation for AS classification have not been elucidated. Integrating multi-detector computed tomography (MDCT) and Doppler data may improve diagnostic accuracy in patients with LFLG AS.nnnMETHODSnA total of 186 patients with severe AS evaluated for transcatheter aortic valve replacement were classified according to indexed stroke volume (SVI, cut-off 35mL/m2) and mean transaortic pressure gradient (cut-off 40mmHg). SVI was calculated using a) the biplane Simpsons method, b) left ventricular outflow tract (LVOT) velocity time integral (VTI) and LVOT diameter determined by 2D echocardiography, or c) LVOT VTI and LVOT area planimetered by MDCT.nnnRESULTSnSVI assessed by the biplane Simpsons method was smaller than that obtained from 2D echocardiography LVOT diameter (29.5±0.6 vs 34.9±0.8mL/m2, p<0.001). The latter was smaller than SVI calculated by integrating MDCT and Doppler data (47.5±1.4mL/m2, p<0.001). LFLG and paradoxical LFLG severe AS were diagnosed in 42.5% and 27.4% of patients using the biplane Simpsons method, in 30.1% and 16.7% using 2D echocardiography LVOT diameter, and in 17.2% and 8.1% when integrating MDCT and Doppler data.nnnCONCLUSIONSnThe prevalence of LFLG and paradoxical LFLG severe AS was overestimated by 2.5- and 3.4-fold based on 2D echocardiography alone. Integration of MDCT and Doppler data should be considered for stroke volume assessment in the classification of severe AS.

Isolated hypoplasia of the left ventricular apex

A 44-year-old female personal trainer complaining of intermittent left sided atypical chest pain radiating to the left arm and chin presented to our out-patient clinic for cardiological workup. Her exercise capacity and physical examination were unremarkable. A coronary CT scan showed normal coronaries but raised the suspicion of an apical left ventricular tumor. Cardiac MRI (Fig. 1) showed normal left ventricular function, however the left ventricle appeared spherically configured and truncated at the apex (Panel A). Papillary muscles originated from the flattened apex and an apical diverticulum was present (Panel A). Right ventricle was elongated and wrapped around the deficient left apex. There was no late gadolinium enhancement of the myocardium (Panel B). T1-weighted imaging (Panel C, arrow) with fat suppression (Panel D, arrow) confirmed epicardial fatty tissue without evidence of any tumor. These findings are consistent with isolated left ventricular (LV) apical hypoplasia. A presumably very rare congenital but most probably under-diagnosed cardiomyopathy first described in 2004 [1]. Pathogenesis and prognosis of isolated LV apical hypoplasia remains unclear. However, patients should be monitored closely for

Severe myocardial ischaemia after neonatal arterial switch operation

A 24-year-old male patient presented for a routine yearly check-up. As a neonate, he underwent an arterial switch operation for d-transposition of the great arteries. He complained of shortness of breath on exertion and typical chest pain since 6 weeks. Transthoracic echocardiography was unremarkable. Treadmill examination showed no signs of ischaemia but …