Electrophysiological cardiovascular MR: procedure-ready mesh model generation for interventional guidance based on non-selective excitation compressed sensing whole heart imaging.

Fully CMR-guided electrophysiological interventions (EP-CMR) have recently been introduced but data on the optimal CMR imaging protocol are scarce. This study determined the clinical utility of 3D non-selective whole heart steady-state free precession imaging using compressed SENSE (nsWHcs) for automatic segmentation of cardiac cavities as the basis for targeted catheter navigation during EP-CMR cavo-tricuspid isthmus ablation. Fourty-two consecutive patients with isthmus-dependent right atrial flutter underwent EP-CMR radiofrequency ablations. nsWHcs succeeded in all patients (nominal scan duration, 98 ± 10 s); automatic segmentation/generation of surface meshes of right-sided cavities exhibited short computation times (16 ± 3 s) with correct delineation of right atrium, right ventricle, tricuspid annulus and coronary sinus ostium in 100%, 100%, 100% and 95%, respectively. Point-by-point ablation adhered to the predefined isthmus line in 62% of patients (26/42); activation mapping confirmed complete bidirectional isthmus block (conduction time difference, 136 ± 28 ms). nsWHcs ensured automatic and reliable 3D segmentation of targeted endoluminal cavities, multiplanar reformatting and image fusion (e.g. activation time measurements) and represented the basis for precise real-time active catheter navigation during EP-CMR ablations of isthmus-dependent right atrial flutter. Hence, nsWHcs can be considered a key component in order to advance EP-CMR towards the ultimate goal of targeted substrate-based ablation procedures.

Cardiovascular magnetic resonance pulmonary perfusion for functional assessment of pulmonary vein stenosis.

BACKGROUND: Cardiovascular magnetic resonance (CMR) imaging allows to combine pulmonary perfusion measurements and pulmonary venous angiography during a single-session examination with both imaging modules representing the basis for accurate diagnosis and therapeutic stratification of pulmonary vein (PV) stenosis. The present study investigated the clinical utility of dynamic pulmonary perfusion imaging integrated into a comprehensive CMR protocol for the evaluation of patients with suspected PV stenosis. METHODS: 162 patients with clinically suspected PV stenosis after catheter ablation of atrial fibrillation underwent a combined single-session CMR examination (cardiac cine imaging, dynamic pulmonary perfusion, and three-dimensional PV angiography). CMR angiography was used for visual grading of PV stenoses; dynamic pulmonary perfusion imaging was evaluated per lung lobe visually and quantitatively. RESULTS: All PV stenosis ≥90% showed a visible perfusion deficit of the corresponding lung lobe (60/60, 100%) while all PVs with luminal narrowing <50% exhibited normal pulmonary perfusion (680/680, 100%). However, every third 70-89% stenosis showed a normal pulmonary perfusion (10/31, 32%) while every fourth 50-69% PV stenosis was associated with hypoperfusion of the corresponding lung lobe (9/39, 23%). For quantitative pulmonary perfusion measurements, ROC analysis demonstrated high discriminatory power regarding PV stenosis detection with the highest AUC values for time-to-peak enhancement (cut-off value, 8.5 s). CONCLUSIONS: The combination of CMR angiography and CMR pulmonary perfusion allowed for assessment of the anatomical degree of PV stenosis and its hemodynamic impact on the pulmonary parenchymal level. Thus, the proposed comprehensive CMR protocol provided an efficient diagnostic work-up of patients with suspected PV stenosis.

Cardiovascular magnetic resonance pulmonary perfusion for guidance of interventional treatment of pulmonary vein stenosis.

BACKGROUND: Pulmonary vein (PV) stenosis represents a rare but serious complication following radiofrequency ablation of atrial fibrillation with a comprehensive diagnosis including morphological stenosis grading together with the assessment of its functional consequences being imperative within the relatively narrow window for therapeutic intervention. The present study determined the clinical utility of a combined, single-session cardiovascular magnetic resonance (CMR) imaging protocol integrating pulmonary perfusion and PV angiographic assessment for pre-procedural planning and follow-up of patients referred for interventional PV stenosis treatment. METHODS: CMR examinations (cine imaging, dynamic pulmonary perfusion, three-dimensional PV angiography) were performed in 32 consecutive patients prior to interventional treatment of PV stenosis and at 1-day and 3-months follow-up. Degree of PV stenosis was visually determined on CMR angiography; visual and quantitative analysis of pulmonary perfusion imaging was done for all five lung lobes. RESULTS: Interventional treatment of PV stenosis achieved an acute procedural success rate of 90%. Agreement between visually evaluated pulmonary perfusion imaging and the presence or absence of a ≥ 70% PV stenosis was nearly perfect (Cohen's kappa, 0.96). ROC analysis demonstrated high discriminatory power of quantitative pulmonary perfusion measurements for the detection of ≥ 70% PV stenosis (AUC for time-to-peak enhancement, 0.96; wash-in rate, 0.93; maximum enhancement, 0.90). Quantitative pulmonary perfusion analysis proved a very large treatment effect attributable to successful PV revascularization already after 1 day. CONCLUSION: Integration of CMR pulmonary perfusion imaging into the clinical work-up of patients with PV stenosis allowed for efficient peri-procedural stratification and follow-up evaluation of revascularization success.

Major incidental findings on routine cardiovascular magnetic resonance imaging prior to first-time catheter ablation of atrial fibrillation.

INTRODUCTION: Preprocedural cardiovascular magnetic resonance (CMR) or computed tomography (CT) imaging of the left atrium/pulmonary veins is usually employed to guide catheter ablation of atrial fibrillation (AFCA). Incidental findings (IFs) are common on cardiac imaging prior to AFCA. However, previous studies have mainly focused on extracardiac IFs detected on CT scan. We aimed to assess the prevalence of relevant cardiac and extracardiac IFs on routine preprocedural CMR in a large patient cohort scheduled for first-time AFCA and report its impact on clinical decision-making and management. METHODS AND RESULTS: We included 2000 consecutive patients (62 ± 10 years; 59% male) who underwent CMR prior to first-time AFCA between April 2015 and March 2019. Among these patients 172 (8.6%) had a total of 184 major IFs. Detection of major IFs resulted in cancellation of the scheduled AFCA procedure in 88 patients (4.4%). Forty-two patients (2.1%) have never been ablated, 46 (2.3%) underwent postponed AFCA after a median time of 83 (32-213) days. The remaining 84 patients (4.2%) underwent an individualized approach to AFCA. The most common major IFs were accessory or anomalous PVs in 76 (3.8%), extracardiac abnormalities suspicious of malignancy in 29 (1.5%), and positive stress perfusion imaging in 19 (7.2% of 261 tested) patients. In 19 patients (1.0%) preprocedural CMR provided the diagnosis of a previously unknown structural cardiac disease. CONCLUSIONS: Unexpected relevant findings on routine preprocedural CMR affected clinical decision-making and management in 8.6% of patients scheduled for first-time AFCA. However, whether preprocedural CMR imaging may improve overall clinical outcome needs to be addressed in future research.

Cardiovascular magnetic resonance-based predictors of complete left ventricular systolic functional recovery after rhythm restoration in patients with atrial tachyarrhythmia.

AIMS: To establish a cardiovascular magnetic resonance (CMR)-based prediction model for complete systolic left ventricular ejection fraction (LVEF) recovery for the distinction of 'arrhythmia-induced' from 'arrhythmia-mediated' cardiomyopathy in patients with atrial tachyarrhythmias. METHODS AND RESULTS: Two hundred and fifty-three tachyarrhythmia patients referred for catheter ablation were enrolled and underwent CMR baseline imaging; patients with a reduced LVEF <50% at baseline and CMR imaging at 3-month follow-up after successful rhythm restoration constituted the final study population (n = 134). CMR at baseline consisted of standard functional cine imaging, determination of extracellular volume, and late gadolinium enhancement (LGE) imaging; follow-up CMR comprised standard functional cine imaging. Left ventricular end-diastolic volume index (LVEDVI) measurements were categorized in 'opposite', 'normal', and 'enlarged'. At follow-up, 80% (107/134) presented with complete LVEF recovery, while in 20% (27/134) persistent LVEF impairment was observed. LVEDVI and LGE were independent predictors of complete LVEF recovery with LGE adding significant incremental value on logistic regression modelling. Model-derived probabilities for complete LVEF recovery in LVEDVI categories of opposite, normal, and enlarged for LGE negativity and positivity were 94%, 85%, and 29% and 77%, 55%, and 8%, respectively. CONCLUSION: CMR-derived assessment of LVEDVI category and LGE allowed for identification of arrhythmia-induced cardiomyopathy with acceptable discriminative performance. Probabilities for complete LVEF recovery for the combination of opposite LVEDVI/LGE negativity and enlarged LVEDVI/LGE positivity were 94% and 8%, respectively. The CMR-based prediction model of complete LVEF recovery can be used to perform upfront stratification in atrial tachyarrhythmia-related LVEF impairment.

Upstream Statin Therapy and Long-Term Recurrence of Atrial Fibrillation after Cardioversion: A Propensity-Matched Analysis.

The relationship of statin therapy with recurrence of atrial fibrillation (AF) after cardioversion (CV) has been evaluated by several investigations, which provided conflicting results and particularly long-term data is scarce. We sought to examine whether upstream statin therapy is associated with long-term recurrence of AF after CV. This was a single-center registry study including consecutive AF patients (n = 454) undergoing CV. Cox regression models were performed to estimate AF recurrence comparing patients with and without statins. In addition, we performed a propensity score matched analysis with a 1:1 ratio. Statins were prescribed to 183 (40.3%) patients. After a median follow-up period of 373 (207-805) days, recurrence of AF was present in 150 (33.0%) patients. Patients receiving statins had a significantly lower rate of AF recurrence (log-rank p < 0.001). In univariate analysis, statin therapy was associated with a significantly reduced rate of AF recurrence (HR 0.333 (95% CI 0.225-0.493), p = 0.001), which remained significant after adjustment (HR 0.238 (95% CI 0.151-0.375), p < 0.001). After propensity score matching treatment with statins resulted in an absolute risk reduction of 27.5% for recurrent AF (21 (18.1%) vs. 53 (45.7%); p < 0.001). Statin therapy was associated with a reduced risk of long-term AF recurrence after successful cardioversion.

Dynamic changes in the signal-averaged electrocardiogram are associated with the long-term outcomes after ablation of ischemic ventricular tachycardia.

PURPOSE: Signal-averaged ECG (SAECG) can detect inhomogeneous myocardial conduction in patients presenting with ventricular tachycardia (VT) after myocardial infarction. Radiofrequency ablation (RFCA) aims at elimination of the endocardial late potentials and non-inducibility of VT. Previously, we demonstrated that abnormal SAECG at baseline can return to normal after a successful VT ablation. The present research investigates the post-ablation changes in SAECG after RFCA of VT and their relation to the procedural long-term outcomes. METHODS: Thirty-three patients (31 male; age 68 ± 9 years; EF 36 ± 12%) with ischemic VT were prospectively enrolled to receive RFCA. One VT (range 1-7) per patient was ablated using substrate-guided RFCA and complete success was achieved in 28 (85%) cases. SAECG was performed before (t1), immediately after (t2), and at least 6 months (t3) after the RFCA. RESULTS: After RFCA, the amount of patients showing abnormal SAECG decreased from 82% initially (t1) to 57.6% post-interventionally (t2); P = 0.008; and remained unchanged thereafter in 57% (t3). Patients who experienced VT recurrence (VT+) during the follow-up period had broader averaged QRS (t2): (VT+) 150 ± 26 vs. (VT-) 129 ± 21 ms; P = 0.015, as well as longer LAS40 (t2): (VT+) 60 ± 26 vs. (VT-) 43 ± 18 ms; P = 0.03. Abnormal SAECG (t2) was a strong predictor for VT recurrence: HR 5.4; 95% CI 1.5-21. SAECG detected more late potentials in patients with inferior than in those with anterior scars: 95% vs. 58%; P = 0.016. CONCLUSIONS: RFCA of VT in the left ventricle can improve an abnormal SAECG in some patients after myocardial infarction. Normal SAECG after RFCA of VT is associated with a lower risk for VT recurrence and death.

Clinical utility of cardiovascular magnetic resonance imaging in patients with implantable cardioverter defibrillators presenting with electrical instability or worsening heart failure symptoms.

BACKGROUND: Data on the usefulness of cardiovascular magnetic resonance (CMR) imaging for clinical decision making in patients with an implanted cardioverter defibrillator (ICD) are scarce. The present study determined the impact of CMR imaging on diagnostic stratification and treatment decisions in ICD patients presenting with electrical instability or progressive heart failure symptoms. METHODS: 212 consecutive ICD patients underwent 1.5 T CMR combining diagnostic imaging modules tailored to the individual clinical indication (ventricular function assessment, myocardial tissue characterization, adenosine stress-perfusion, 3D-contrast-enhanced angiography); four CMR examinations (4/212, 2%) were excluded due to non-diagnostic CMR image quality. The resultant change in diagnosis or clinical management was determined in the overall population and compared between ICD patients for primary (115/208, 55%) or secondary prevention (93/208, 45%). Referral indication consisted of documented ventricular tachycardia, inadequate device therapy or progressive heart failure symptoms. RESULTS: Overall, CMR imaging data changed diagnosis in 40% (83/208) with a significant difference between primary versus secondary prevention ICD patients (37/115, 32% versus 46/93, 49%, respectively; p = 0.01). The information gain from CMR led to an overall change in treatment in 21% (43/208) with a similar distribution in primary versus secondary prevention ICD patients (25/115,22% versus 18/93,19%, p = 0.67). The effect on treatment change was highest in patients initially scheduled for ventricular tachycardia ablation procedure (18/141, 13%) with revision of the treatment plan to medical therapy or coronary revascularization. CONCLUSIONS: CMR imaging in ICD patients presenting with electrical instability or worsening heart failure symptoms provided diagnostic or management-changing information in a considerable proportion (40% and 21%, respectively).

Combined single-session cardiovascular magnetic resonance: stress perfusion and three-dimensional pulmonary vein angiography for stratification of atrial fibrillation patients with chest pain syndromes prior to catheter ablation.

AIMS: To determine the clinical utility of a combined single-session cardiovascular magnetic resonance (CMR) imaging protocol integrating adenosine stress perfusion and three-dimensional pulmonary vein angiography for stratification of atrial fibrillation (AF) patients referred for pulmonary vein isolation (PVI) and complaining about chest pain syndromes. METHODS AND RESULTS: The preprocedural CMR examination (adenosine stress perfusion, late gadolinium enhancement, and three-dimensional pulmonary vein angiography) was performed in 357 consecutive AF patients with chest pain syndromes referred for PVI. Stress perfusion results were used for stratification: ischaemia positive patients underwent invasive coronary angiography, ischaemia negative patients underwent PVI, and follow-up/outcome data were collected (combined primary endpoint of cardiac death/non-fatal myocardial infarction). The integrated CMR protocol had a high success rate (356/357, 99.7%), a short total examination duration (<30 min in all patients), and delivered high-quality three-dimensional pulmonary vein angiography in all patients undergoing PVI (324/324, 100%). Variants of pulmonary vein anatomy were identified in 33% of all patients (117/357). Stress positivity (28/356, 8%) had a high positive predictive value for identification of obstructive coronary artery disease (86%), while stress negativity carried a low short-term event rate following PVI (cumulative 1-year event-free survival rate, 99.6%). CONCLUSION: Combined single-session CMR as a routine diagnostic workup for AF patients with chest pain syndromes prior to PVI proved to represent a time-efficient and effective stratification tool.

Agreement between gadolinium-enhanced cardiac magnetic resonance and electro-anatomical maps in patients with non-ischaemic dilated cardiomyopathy and ventricular arrhythmias.

AIMS: We sought to investigate the overlap between late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischaemic dilated cardiomyopathy (NIDCM) and how it relates with the outcomes after catheter ablation of ventricular arrhythmias (VA). METHODS AND RESULTS: We identified 50 patients with NIDCM who received CMR and ablation for VA. Late gadolinium enhancement was detected in 16 (32%) patients, mostly in those presenting with sustained ventricular tachycardia (VT): 15 patients. Low-voltage areas (<1.5 mV) were observed in 23 (46%) cases; in 7 (14%) cases without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 and 5 mV for bipolar and unipolar maps, respectively. Most VT exits (12 out of 16 patients) were found in areas with LGE. VT exits were found in segments without LGE in two patients with VT recurrence as well as in two patients without recurrence, P = 0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12% ± 5.8% vs. 6.9% ± 3.4%; P = 0.049. CONCLUSIONS: In NIDCM, the agreement between LGE and bipolar EAM was fairly poor but can be improved with adjustment of the thresholds for EAM according to the amount of LGE. The outcomes were related to the volume of LGE.

Clinical workflow and applicability of electrophysiological cardiovascular magnetic resonance-guided radiofrequency ablation of isthmus-dependent atrial flutter.

Aims: To determine safety and efficacy of electrophysiological cardiovascular magnetic resonance (EP-CMR)-guided radiofrequency (RF) ablation in patients with typical right atrial flutter in a routine clinical setting. Methods and results: Thirty patients with typical right atrial flutter underwent clinically indicated EP-CMR-guided cavotricuspid isthmus ablation. EP-CMR protocols included pre- and post-ablation CMR imaging (whole heart, T2-weighted, and early-/late-gadolinium enhancement) together with electroanatomic mapping of the right atrium. Coronary sinus cannulation time and total ablation procedure duration were used as performance measures to determine the learning experience of the EP-CMR interventionalist and for comparison with conventional, fluoroscopy-guided atrial flutter ablation. Procedural safety and success rates were evaluated at 1 week and 3 months follow-up. Safety and success rates of EP-CMR were similar to conventional flutter ablations (primary success rate, 93% vs. 100%; recurrence rate, 0% vs. 3%, respectively). EP-CMR procedure duration indicated a learning experience (first vs. last six patients, 54.2 ± 23.1 vs. 29.7 ± 20.0 min) and the minimum number of procedures needed to achieve a level of competency was n = 12. An isthmus angle <110° and the presence of pouch-like isthmus anatomy were indicative of significantly prolonged EP-CMR procedure duration. CMR-defined ablation lesion size was not associated with total RF-ablation time or RF-induced maximum temperature. Conclusion: In a routine clinical setting, EP-CMR demonstrated its safety and high efficacy for the treatment of typical right atrial flutter with performance and outcome measures similar to conventional, fluoroscopy-guided flutter ablation. Hence, EP-CMR represents a valid alternative to conventional right atrial flutter ablation.

Characteristics of the ablation lesions in cardiac magnetic resonance imaging after radiofrequency ablation of ventricular arrhythmias in relation to the procedural success.

BACKGROUND: In human patients, studies about the cardiac magnetic resonance (CMR) appearance of the acute radiofrequency (RF) lesions in relation to the procedural outcomes after catheter ablation (CA) of ventricular arrhythmias (VA) are scarce. We aimed to investigate the RF lesions characteristics in relation to the procedural success. METHODS: Patients referred for ablation of VA received CMR (1.5 T) using gadolinium contrast before and after ablation. CA in left ventricle was performed using a 3.5-mm irrigated catheter. The volume and transmurality of the RF-induced lesions were measured in early gadolinium-enhanced postablation CMRs. Acute failure was defined as persistently inducible VA at the end of the CA. RESULTS: Twenty-five patients (60.7 ±â€¯9.8 years, 19 with sustained ventricular tachycardia) were studied. All RF lesions had nonenhanced core. The volume of the nonenhanced lesions showed positive correlation with the maximal RF power (r = 0.598, P = .002) and the impedance drop (r = 0.416, P = .038). Patients with transmural (≥75%) lesions had significantly larger impedance drop as compared to those with nontransmural lesions (<75%): 20.3 ±â€¯9.4 versus 13.5 ±â€¯4.3, P = .037. In the failures, the lesions volume was nonsignificantly larger: 3.86 ±â€¯3.3% versus 2.6 ±â€¯1.7%, P = .197; however, it was considerably deeper: 86 ±â€¯13% versus 62 ±â€¯26%, P = .03. CONCLUSIONS: CMR after VA ablation showed nonenhanced lesions resembling the no-reflow phenomenon in myocardial infarction. Although the size and the depth of the RF injury correlated with the ablation energy and impedance drop, they were not associated with acute ablation success.

Artefact-free late gadolinium enhancement imaging in patients with implanted cardiac devices using a modified broadband sequence: current strategies and results from a real-world patient cohort.

Aims: Cardiac magnetic resonance (CMR) imaging in patients with implanted cardiac devices is often limited by device-related imaging artefacts. Limitations can potentially be overcome by employing a broadband late gadolinium enhancement (LGE)-CMR imaging technique. The purpose of this study was to investigate the relationship between implanted cardiac devices and the optimal frequency offset on broadband LGE-CMR imaging to increase the artefact-free visibility of myocardial segments. Methods and results: A phantom study was performed to characterize magnetic field disturbances related to 15 different cardiac devices. This was complemented by B0 and B1+ imaging of three different device types in four healthy volunteers. Findings were validated in 28 patients with an indication for arrhythmogenic substrate characterization before catheter ablation. In the phantom study, the placement of a PM, implantable cardioverter-defibrillator (ICD) or CRT-D generator led to a significant impairment of the radiofrequency field. B0 mapping in phantom and volunteers showed the highest off-resonance maximum with CRT-D systems with the maximum off-resonance significantly decreasing for ICD or PM systems, respectively. In all patients, with conventional LGE imaging 73.1% (61.5-92.3%) of LV segments were free of device-related artefacts, while with the broadband LGE technique, a significant increase of artefact-free segments was achieved [96.4% (85.7-100%); P = 0.00008]. Conclusion: Using a modified broadband sequence for LGE imaging significantly increased the number of artefact-free myocardial segments thereby leading to improved diagnostic value of the CMR exam. Since the occurrence and extent of hyperintensity artefacts are closely related to the individual device, more studies are warranted to evaluate if the results can be extrapolated to other devices and manufacturers.

Subacute and Chronic Left Ventricular Myocardial Scar: Accuracy of Texture Analysis on Nonenhanced Cine MR Images.

Purpose To test whether texture analysis (TA) allows for the diagnosis of subacute and chronic myocardial infarction (MI) on noncontrast material-enhanced cine cardiac magnetic resonance (MR) images. Materials and Methods In this retrospective, institutional review board-approved study, 120 patients who underwent cardiac MR imaging and showed large transmural (volume of enhancement on late gadolinium enhancement [LGE] images >20%, n = 72) or small (enhanced volume ≤20%, n = 48) subacute or chronic ischemic scars were included. Sixty patients with normal cardiac MR imaging findings served as control subjects. Regions of interest for TA encompassing the left ventricle were drawn by two blinded, independent readers on cine images in end systole by using a freely available software package. Stepwise dimension reduction and texture feature selection based on reproducibility, machine learning, and correlation analyses were performed for selecting features, enabling the diagnosis of MI on nonenhanced cine MR images by using LGE imaging as the standard of reference. Results Five independent texture features allowed for differentiation between ischemic scar and normal myocardium on cine MR images in both subgroups: Teta1, Perc.01, Variance, WavEnHH.s-3, and S(5,5)SumEntrp (in patients with large MI: all P values < .001; in patients with small MI: Teta1 and Perc.01, P < .001; Variance, P = .026; WavEnHH.s-3, P = .007; S[5,5]SumEntrp, P = .045). Multiple logistic regression models revealed that combining the features Teta1 and Perc.01 resulted in the highest accuracy for diagnosing large and small MI on cine MR images, with an area under the curve of 0.93 and 0.92, respectively. Conclusion This proof-of-concept study indicates that TA of nonenhanced cine MR images allows for the diagnosis of subacute and chronic MI with high accuracy. © RSNA, 2017 Online supplemental material is available for this article.

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 > 50% 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 an image quality being rated as good to excellent (mean scores 3.5 ± 0.5 and 3.7 ± 0.4, 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 (22/23 = 96%). Compared to separate analysis of CT and CMR data, coronary supply territories of 3D-CMR-Perf perfusion deficits were refined in two cases (2/23 = 9%), and the relevance of stenoses in CTCA was re-judged in four cases (4/23 = 17%). In conclusion, 3D 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.

Cardiovascular magnetic resonance imaging in patients with cardiac implantable electronic devices: a device-dependent imaging strategy for improved image quality.

Aims: To prospectively determine evaluability of routine cardiovascular magnetic resonance (CMR) diagnostic modules in a referral population of implanted rhythm device all-comers, and to establish a device-dependent CMR imaging strategy to achieve optimal image quality. Methods and results: One hundred and twenty-eight patients with cardiac implantable electronic devices [insertable cardiac monitoring system, n = 14; implantable loop-recorder, n = 21; pacemaker, n = 31; implantable cardioverter-defibrillator (ICD), n = 50; and cardiac resynchronization therapy defibrillator (CRT-D), n = 12] underwent clinically indicated CMR at 1.5 T. CMR protocols were tailored to the clinical indication and consisted of cine, perfusion, T1-/T2-weighted, late-gadolinium enhancement (LGE), 3D angiographic, and post-contrast cine spoiled gradient echo (SGE) scans. Image quality was determined using a 4-grade visual score per myocardial segment. Segmental evaluability was strongly influenced by device type and location with the highest proportion of non-diagnostic images encountered in the presence of ICD/CRT-D systems. Cine steady-state free-precession (SSFP) imaging was found to be mostly non-diagnostic in ICD/CRT-D patients, but a significant improvement of image quality was demonstrated when using SGE sequences with a further incremental improvement post-contrast resulting in an overall four-fold higher likelihood of achieving good image quality. LGE scans were found to be non-diagnostic in about one-third of left-ventricular segments of ICD/CRT-D patients but were artefact-free in > 94% for all other device types. Conclusion: Device type and location constitute the main independent predictors of CMR image quality and thus, need to be considered during protocol adaptation. Most notably, post-contrast SGE cine imaging proved superior to conventionally used SSFP sequences. Thus, following the proposed device-dependent CMR imaging strategy, diagnostic image quality can be achieved in the majority of device patients.

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.

AIMS: Coronary 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. METHODS AND RESULTS: Four 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 65 ± 11 and 63 ± 11 years, 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 (P = 0.474 and P = 0.83, 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 (P = 0.134 and P = 0.936, 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. CONCLUSION: Whole-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.

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

BACKGROUND: The 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. METHODS: Twelve patients undergoing coronary CTA/CT-Perf after heart transplantation were included (56 ± 12 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. RESULTS: CT image quality was rated good-excellent (3.5 ± 0.5, 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 (1/2 = 50%) and diagnostic findings could be rectified in the other case (1/2 = 50%). Coronary CTA was in full correspondence with catheter coronary angiography. CONCLUSION: A method for 3D fusion of coronary CTA/CT-Perf is introduced correlating relevant coronary lesions and corresponding stress-induced myocardial perfusion deficits.

ECG morphology of premature ventricular contractions predicts the presence of myocardial fibrotic substrate on cardiac magnetic resonance imaging in patients undergoing ablation.

BACKGROUND: The most likely origin of premature ventricular contractions (PVCs) may be deduced from surface electrocardiogram (ECG) analysis while planning an electrophysiological study (EPS). Apart from purely benign forms of increased ventricular ectopy, myocardial substrate (e.g., regional fibrosis) may be present in certain cases, which will significantly impact the ablation approach. Cardiac magnetic resonance (CMR) imaging can reliably identify fibrotic target lesions and, hence, may assist in adequate patient selection and procedural planning. METHODS AND RESULTS: We analyzed 101 patients (59% males, mean age 57.15 ± 15.5 years, mean PVC count 19,801 ± 14,021 per 24 hours) referred for ablation of PVCs. The CMR (1.5T, Philips Ingenia, Best, The Netherlands) protocol included cine and three-dimensional-delayed enhancement imaging using standard cardiac geometries. On surface, ECG right bundle branch block (RBBB) morphology was present in 43% of patients. Twenty-one patients showed the fibrotic substrate on CMR. On univariate analysis, both RBBB morphology (P < 0.001) and presence of multiple PVC morphologies (≥2) significantly predicted the presence of fibrotic substrate (P = 0.01), which various baseline characteristics including left ventricular ejection fraction (45.7 ± 12.6% vs. 50.6 ± 11.0%, P = 0.08) failed to do. CMR-identified fibrosis was associated with the site of origin of the clinical PVCs during EPS and was successfully treated by radiofrequency ablation in 93% (PVC reduction >95%). CONCLUSION: In patients with RBBB morphology and/or multiple PVC patterns, CMR imaging before ablation may be helpful due to the increased prevalence of fibrotic lesions with regard to patient stratification and periprocedural management.