Cardiovascular Magnetic Resonance Imaging Feature Tracking: Impact of Training on Observer Performance and Reproducibility

BACKGROUND: Cardiovascular magnetic resonance feature tracking (CMR-FT) is increasingly used for myocardial deformation assessment including ventricular strain, showing prognostic value beyond established risk markers if used in experienced centres. Little is known about the impact of appropriate training on CMR-FT performance. Consequently, this study aimed to evaluate the impact of training on observer variance using different commercially available CMR-FT software. METHODS: Intra- and inter-observer reproducibility was assessed prior to and after dedicated one-hour observer training. Employed FT software included 3 different commercially available platforms (TomTec, Medis, Circle). Left (LV) and right (RV) ventricular global longitudinal as well as LV circumferential and radial strains (GLS, GCS and GRS) were studied in 12 heart failure patients and 12 healthy volunteers. RESULTS: Training improved intra- and inter-observer reproducibility. GCS and LV GLS showed the highest reproducibility before (ICC \u3e0.86 and \u3e0.81) and after training (ICC \u3e0.91 and \u3e0.92). RV GLS and GRS were more susceptible to tracking inaccuracies and reproducibility was lower. Inter-observer reproducibility was lower than intra-observer reproducibility prior to training with more pronounced improvements after training. Before training, LV strain reproducibility was lower in healthy volunteers as compared to patients with no differences after training. Whilst LV strain reproducibility was sufficient within individual software solutions inter-software comparisons revealed considerable software related variance. CONCLUSION: Observer experience is an important source of variance in CMR-FT derived strain assessment. Dedicated observer training significantly improves reproducibility with most profound benefits in states of high myocardial contractility and potential to facilitate widespread clinical implementation due to optimized robustness and diagnostic performance

Compressed SENSE accelerated 3D single-breath-hold late gadolinium enhancement cardiovascular magnetic resonance with isotropic resolution: clinical evaluation

AimThe purpose of this study was to investigate the clinical application of Compressed SENSE accelerated single-breath-hold LGE with 3D isotropic resolution compared to conventional LGE imaging acquired in multiple breath-holds.Material & MethodsThis was a retrospective, single-center study including 105 examinations of 101 patients (48.2 ± 16.8 years, 47 females). All patients underwent conventional breath-hold and 3D single-breath-hold (0.96 × 0.96 × 1.1 mm3 reconstructed voxel size, Compressed SENSE factor 6.5) LGE sequences at 1.5 T in clinical routine for the evaluation of ischemic or non-ischemic cardiomyopathies. Two radiologists independently evaluated the left ventricle (LV) for the presence of hyperenhancing lesions in each sequence, including localization and transmural extent, while assessing their scar edge sharpness (SES). Confidence of LGE assessment, image quality (IQ), and artifacts were also rated. The impact of LV ejection fraction (LVEF), heart rate, body mass index (BMI), and gender as possible confounders on IQ, artifacts, and confidence of LGE assessment was evaluated employing ordinal logistic regression analysis.ResultsUsing 3D single-breath-hold LGE readers detected more hyperenhancing lesions compared to conventional breath-hold LGE (n = 246 vs. n = 216 of 1,785 analyzed segments, 13.8% vs. 12.1%; p < 0.0001), pronounced at subendocardial, midmyocardial, and subepicardial localizations and for 1%–50% of transmural extent. SES was rated superior in 3D single-breath-hold LGE (4.1 ± 0.8 vs. 3.3 ± 0.8; p < 0.001). 3D single-breath-hold LGE yielded more artifacts (3.8 ± 1.0 vs. 4.0 ± 3.8; p = 0.002) whereas IQ (4.1 ± 1.0 vs. 4.2 ± 0.9; p = 0.122) and confidence of LGE assessment (4.3 ± 0.9 vs. 4.3 ± 0.8; p = 0.374) were comparable between both techniques. Female gender negatively influenced artifacts in 3D single-breath-hold LGE (p = 0.0028) while increased heart rate led to decreased IQ in conventional breath-hold LGE (p = 0.0029).ConclusionsIn clinical routine, Compressed SENSE accelerated 3D single-breath-hold LGE yields image quality and confidence of LGE assessment comparable to conventional breath-hold LGE while providing improved delineation of smaller LGE lesions with superior scar edge sharpness. Given the fast acquisition of 3D single-breath-hold LGE, the technique holds potential to drastically reduce the examination time of CMR

Effect of different conditioning strategies on myocardial function and prognosis after ST-elevation myocardial infarction

Ziel:  Ziel der Arbeit war die umfassende Evaluation des kardialen MRT-basierten myokardialen Feature-Trackings (CMR-FT) in Bezug auf seine Reproduzierbarkeit, seine Anwendbarkeit zur Beurteilung kardioprotektiver Effekte unterschiedlicher Conditioning-Strategien auf die kardiale Funktion und seine Validierbarkeit zur Prognoseeinschätzung nach ST-Streckenhebungs-Myokardinfarkt (STEMI). Material und Methoden:  Anhand der CMR-FT Analyse von zehn Probanden ohne relevante Einschränkung der links-ventrikulären Ejektionsfraktion (LVEF) und zehn Patienten mit signifikant eingeschränkter systolischer Funktion wurden zwei CMR-FT-Softwarelösungen (TomTec, Germany; QStrain, Netherlands) miteinander verglichen und der Effekt wiederholter Messungen auf die Reproduzierbarkeit untersucht. Erhoben wurden die links-ventrikulären Strainparameter globaler longitudinaler Strain (GLS), globaler circumferentieller Strain (GCS) und globaler radialer Strain (GRS).  Der Effekt unterschiedlicher Conditioning-Regime auf die kardiale Funktion wurde durch die Analyse der links-ventrikulären (GLS, GCS, GRS) und links-atrialen Strainparameter (total strain (ε(s)), passive strain (ε(e)) und active strain (ε(a)) sowie die links-ventrikulären Dyssynchronieparameter (die circumferential und radial uniformity ratio estimates CURE und RURE) der unterschiedlichen Interventionsarme der Randomized-LIPSIA-conditioning-Studie analysiert. Zudem wurde der Effekt eines gesteigerten myocardial salvage index (MSI) auf die links-ventrikuläre und links-atriale Funktion untersucht.  Im dritten Abschnitt wurde die externe Validierung etablierter Cut-off Werte links-ventrikulärer (GLS, GCS, GRS) und links-atrialer Strainparameter (ε(s), ε(e), ε(a)) sowie links-ventrikulärer Dyssynchronieparameter (CURE, RURE) für die verbesserte Prognoseeinschätzung nach akutem Myokardinfarkt durch Anwendung dieser Cut-off Werte und Analyse ihres prognostischen Mehrwerts gegenüber etablierten kardiovaskulären Risikofaktoren im Randomized-LIPSIA-conditioning-Kollektiv angestrebt.  Ergebnisse:  Der GLS und der GCS wiesen die geringste Inter-Hersteller-Variabilität und die beste Intra-Hersteller-Reproduzierbarkeit auf. Der GRS zeigte die höchste Variabilität aller CMR-FT-Parameter. Wiederholte Messungen steigerten zwar die Intra-Hersteller-Reproduzierbarkeit des GRS, unabhängig von der Anzahl der Messungen war der mit QStrain gemessene GRS jedoch signifikant höher als mit TomTec. Unabhängig vom gewählten Conditioning-Regime konnte keine wesentliche Verbesserung der CMR-FT-basierten kardialen Mechanik gegenüber einer konventionellen Therapie mittels alleiniger perkutaner koronarer Intervention erreicht werden. Ein positiver Effekt einer Kombinationstherapie aus remote ischemic conditioning und postconditioning ließ sich nicht nachweisen. Hingegen konnten wir erstmals demonstrieren, dass der MSI signifikant mit einer besseren kardialen Funktion assoziiert ist. Ein Korrelat der kardialen Mechanik für einen größeren MSI ließ sich nicht nachweisen.  Die von Eitel, Schuster und Stiermaier et al. identifizierten Cutoff-Werte für den GLS, GCS, GRS, den links-atrialen Strain und den CURE konnten auch im Randomized-LIPSIA-conditioning-Kollektiv die Prognoseabschätzung signifikant verbessern. Anhand des GLS und der links-atrialen Funktionsparameter gelang zudem eine Risikostratifikation bei Patienten mit erhaltener links-ventrikulärer Ejektionsfraktion (LVEF). Der prognostische Mehrwehrt des ε(s) für die Gesamtmortalität zu der LVEF, der Infarktgröße und der mikrovaskulären Obstruktion konnte bestätigt und damit die Bedeutung der links-atrialen Funktion für den klinischen Outcome nach akutem Myokardinfarkt (AMI) gestützt werden. Zudem konnte der ε(s) als Prädiktor für das Auftreten eines schwerwiegenden kardialen Ereignisses, unabhängig von etablierten Risikofaktoren wie der LVEF, dem Alter, der Killip-Klasse und dem GLS, identifiziert werden.  Zusammenfassung:  Diese Arbeit demonstriert erstens die weiterhin unzureichende Inter-Hersteller-Reproduzierbarkeit der unterschiedlichen kommerziell verfügbaren CMR-FT-Softwarelösungen und betont damit die Notwendigkeit einer weiteren technischen Standardisierung sowie einer Etablierung softwareunabhängiger Cutoff-Werte.  Zweitens liefern unsere Ergebnisse einen nennenswerten Beitrag zum besseren Verständnis der Effekte unterschiedlicher Conditioning-Strategien und stärken die Bedeutung des MSI nach AMI als Marker für eine verbesserte kardiale Funktion. Drittens konnte mit dieser Arbeit der prognostische Mehrwert des CMR-FT nach AMI erstmals extern validiert werden.Aim:  To evaluate cardiac MRI-based myocardial feature tracking (CMR-FT) regarding its reproducibility, its feasibility for the assessment of cardioprotective effects of different conditioning strategies on myocardial function and its validation for an optimized risk stratification following ST-elevation myocardial infarction (STEMI).   Material and Methods:  CMR-cine images of 10 patients without significant reduction in left ventricular ejection fraction (LVEF) and 10 patients with a significantly impaired systolic function were analyzed using two different types of FT-software (TomTec, Germany; QStrain, Netherlands). Global left ventricular longitudinal circumferential and radial strains (GLS, GCS and GRS) were assessed. Differences in intra- and inter-observer variability within and between software types based on single and up to three repeated and subsequently averaged measurements were evaluated. The effect of different conditioning strategies on myocardial function was assessed by analyzing left ventricular (GLS, GCS, GRS) and left atrial strain parameters (total strain (ε(s)), passive strain (ε(e)) and active strain (ε(a)) as well as left ventricular dyssynchrony parameters (the circumferential and radial uniformity ratio estimates CURE and RURE) in the different study groups of the Randomized-LIPSIA-conditioning study. Further, we investigated the effect of an increased myocardial salvage index (MSI) on left ventricular and left atrial function.   In the third part we aimed for the external validation of established cut-off values of the left ventricular strain (GLS, GCS, GRS), the left atrial strain (ε(s), ε(e), ε(a)) and the left ventricular dyssynchrony parameters (CURE and RURE) for the optimized risk stratification following STEMI by applying these values as well as assessing their prognostic merit over and above established cardiovascular risk factors in the Randomized-LIPSIA-conditioning cohort.  Results:  Inter-vendor agreement was highest for GCS followed by GLS. GRS showed the lowest inter-vendor agreement. Intra-vendor reproducibility was excellent for GCS and GLS, but lower for GRS. The impact of repeated measurements was most pronounced for GRS on an intra-vendor level. However, regardless of the number of repetitions, GRS was measured significantly higher with QStrain than with TomTec.  Despite the chosen conditioning regimen, there was no significant improvement in CMR-FT-based cardiac mechanics compared to conventional therapy using percutaneous coronary intervention alone. A positive effect of a combination therapy of remote ischemic conditioning and postconditioning could not be demonstrated. In contrast, we were able to show the MSI being significantly associated with a better cardiac function. A correlate of cardiac mechanics for a larger MSI could not be demonstrated. The cut-off values for GLS, GCS, GRS, left atrial strain and the CURE, that were identified by Eitel, Schuster and Stiermaier et al. did also lead to an optimized risk stratification in the Randomized-LIPSIA-conditioning cohort. GLS and left atrial strain parameters even improved risk assessment in patients with preserved left ventricular ejection fraction (LVEF). The prognostic merit of the ε(s) for the prediction of mortality over and above LVEF, infarct size and microvascular obstruction could be validated, supporting the importance of a maintained left atrial function for clinical outcome following acute myocardial infarction (AMI). Moreover, the ε(s) was identified as an independent predictor of major adverse cardiac events independent of established risk factors as LVEF, age, Killip-class and GLS.  Conclusion:  First of all, this study demonstrates the still insufficient inter-vendor reproducibility of different, commercially available CMR-FT software solutions and thus stresses the necessity for further technical standardization between vendors and the establishment of vendor independent cut-off values.  Secondly, our results lead to the considerably improved understanding of the effects of different conditioning strategies and strengthens the importance of the MSI as a marker for an improved cardiac function after AMI. Thirdly, the prognostic merit of CMR-FT after acute myocardial infarction could be externally validated for the first time as the result of this work. 2021-09-1

Detection of patients with chronic thromboembolic pulmonary hypertension by volumetric iodine quantification in the lung-a case control study

Background: To evaluate whether volumetric iodine quantification of the lung allows for the automatic identification of patients with chronic thromboembolic pulmonary hypertension (CTEPH) and whether the extent of pulmonary malperfusion correlates with invasive hemodynamic parameters. Methods: Retrospective data base search identified 30 consecutive patients with CTEPH who underwent CT pulmonary angiography (CTPA) on a spectral-detector CT scanner. Thirty consecutive patients who underwent an identical CT examination for evaluation of suspected acute pulmonary embolism and had no signs of pulmonary embolism or PH, served as control cohort. Lungs were automatically segmented for all patients and normal and malperfused volumes were segmented based on iodine density thresholds. Results were compared between groups. For correlation analysis between the extent of malperfused volume and mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) 3 patients were excluded because of a time span of more than 30 days between CTPA and right heart catheterization. Results: Patients with CTEPH had a higher percentage of malperfused lung compared to controls (43.25%+/- 24.72% vs. 21.82%+/- 20.72%; P=0.001) and showed reduced mean iodine density in malperfused and normal-perfused lung areas, as well as in the vessel volume. Controls showed a left-tailed distribution of iodine density in malperfused lung areas while patients with CTEPH had a more symmetrical distribution (Skew: -0.382 +/- 0.435 vs. -0.010 +/- 0.396; P=0.004). Patients with CTEPH showed a significant correlation between the percentage of malperfused lung volume and the PVR (r=0.57, P=0.001). Conclusions: Volumetric iodine quantification helps to identify patients with CTEPH by showing increased areas of malperfusion. The extent of malperfusion might provide a measurement for disease severity in patients with CTEPH

Value of spectral detector computed tomography to differentiate infected from noninfected thoracoabominal fluid collections

Purpose: To investigate the diagnostic value of spectral detector CT (SDCT)-derived virtual non-contrast (VNC), virtual monoenergetic images (VMI) and iodine overlays (IO) for distinguishing infected from noninfected fluid collections (FC) in the chest or abdomen. Method: This retrospective study included 58 patients with venous phase SDCT with 77 FC. For all included FC, microbiological analysis of aspirated fluid served as reference. For quantitative analysis, wall thickness was measured, and (ROI)-based analysis performed within the fluid, the FC's wall (if any) and the aorta. Two radiologists qualitatively evaluated visibility of wall enhancement, diagnostic confidence regarding infection of fluid collection, confidence of CT-guided drainage catheter placement and visibility of anatomical landmarks in conventional images (CI) and VNC, VMI40keV, IO. Results: Wall thickness significantly differed between infected (n = 46) and noninfected (n = 31) FC (3.5 +/- 1.8 mm vs. 1.4 +/- 1.8 mm, AUC = 0.81; p < 0.05). Fluid attenuation and wall enhancement was significantly higher in infected as compared to noninfected FC in all reconstructions (p < 0.05, respectively). Highest AUC regarding A) attenuation in fluid was yielded in CI and VMI70,80keV (0.75); B) wall enhancement in CI (0.88) followed by iodine concentration (0.86). Contrast-to-noise ratio of wall vs. fluid was highest in VMI40keV (p < 0.05). All assessed qualitative parameters received significantly higher ratings when using spectral reconstructions vs. CI (p for all <0.05), except for visibility of wall enhancement. Conclusion: Spectral reconstructions improve the assessment of infected from noninfected thoracoabdominal fluid collections and depiction of wall enhancement. Diagnostic performance of the quantitative measurements in spectral reconstructions were comparable with measurements in conventional images

Reduction of CT artifacts from cardiac implantable electronic devices using a combination of virtual monoenergetic images and post-processing algorithms

Objectives To evaluate the reduction of artifacts from cardiac implantable electronic devices (CIEDs) by virtual monoenergetic images (VMI), metal artifact reduction (MAR) algorithms, and their combination (VMIMAR) derived from spectral detector CT (SDCT) of the chest compared to conventional CT images (CI). Methods In this retrospective study, we included 34 patients (mean age 74.6 +/- 8.6 years), who underwent a SDCT of the chest and had a CIED in place. CI, MAR, VMI, and VMIMAR (10 keV increment, range: 100-200 keV) were reconstructed. Mean and standard deviation of attenuation (HU) among hypo- and hyperdense artifacts adjacent to CIED generator and leads were determined using ROIs. Two radiologists qualitatively evaluated artifact reduction and diagnostic assessment of adjacent tissue. Results Compared to CI, MAR and VMIMAR >= 100 keV significantly increased attenuation in hypodense and significantly decreased attenuation in hyperdense artifacts at CIED generator and leads (p = 100 keV alone only significantly decreased hyperdense artifacts at the generator (p = 100 keV, MAR, and VMIMAR >= 100 keV provided significant reduction of hyper- and hypodense artifacts resulting from the generator and improved diagnostic assessment of surrounding structures (p = 140 with and without MAR significantly worsened diagnostic assessment (p < 0.05). Conclusions The combination of VMI and MAR as well as MAR as a standalone approach provides effective reduction of artifacts from CIEDs. Still, higher keV values should be applied with caution due to a loss of soft tissue and vessel contrast along the leads

Spectral Detector CT-Derived Pulmonary Perfusion Maps and Pulmonary Parenchyma Characteristics for the Semiautomated Classification of Pulmonary Hypertension

ObjectivesTo evaluate the usefulness of spectral detector CT (SDCT)-derived pulmonary perfusion maps and pulmonary parenchyma characteristics for the semiautomated classification of pulmonary hypertension (PH). MethodsA total of 162 consecutive patients with right heart catheter (RHC)-proven PH of different aetiologies as defined by the current ESC/ERS guidelines who underwent CT pulmonary angiography (CTPA) on SDCT and 20 patients with an invasive rule-out of PH were included in this retrospective study. Semiautomatic lung segmentation into normal and malperfused areas based on iodine density (ID) as well as automatic, virtual non-contrast-based emphysema quantification were performed. Corresponding volumes, histogram features and the ID Skewness(PerfDef)-Emphysema-Index (delta-index) accounting for the ratio of ID distribution in malperfused lung areas and the proportion of emphysematous lung parenchyma were computed and compared between groups. ResultsPatients with PH showed a significantly greater extent of malperfused lung areas as well as stronger and more homogenous perfusion defects. In group 3 and 4 patients, ID skewness revealed a significantly more homogenous ID distribution in perfusion defects than in all other subgroups. The delta-index allowed for further subclassification of subgroups 3 and 4 (p < 0.001), identifying patients with chronic thromboembolic PH (CTEPH, subgroup 4) with high accuracy (AUC: 0.92, 95%-CI, 0.85-0.99). ConclusionAbnormal pulmonary perfusion in PH can be detected and quantified by semiautomated SDCT-based pulmonary perfusion maps. ID skewness in malperfused lung areas, and the delta-index allow for a classification of PH subgroups, identifying groups 3 and 4 patients with high accuracy, independent of reader expertise

Inter-vendor reproducibility of left and right ventricular cardiovascular magnetic resonance myocardial feature-tracking

<div><p>Aim</p><p>Since cardiovascular magnetic resonance feature-tracking (CMR-FT) has been demonstrated to be of incremental clinical merit we investigated the interchangeability of global left and right ventricular strain parameters between different CMR-FT software solutions.</p><p>Material and methods</p><p>CMR-cine images of 10 patients without significant reduction in LVEF and RVEF and 10 patients with a significantly impaired systolic function were analyzed using two different types of FT-software (TomTec, Germany; QStrain, Netherlands). Global longitudinal strains (LV GLS, RV GLS), global left ventricular circumferential (GCS) and radial strains (GRS) were assessed. Differences in intra- and inter-observer variability within and between software types based on single and up to three repeated and subsequently averaged measurements were evaluated.</p><p>Results</p><p>Inter-vendor agreement was highest for GCS followed by LV GLS. GRS and RV GLS showed lower inter-vendor agreement. Variability was consistently higher in healthy volunteers as compared to the patient group. Intra-vendor reproducibility was excellent for GCS, LV GLS and RV GLS, but lower for GRS. The impact of repeated measurements was most pronounced for GRS and RV GLS on an intra-vendor level.</p><p>Conclusion</p><p>Cardiac pathology has no influence on CMR-FT reproducibility. LV GLS and GCS qualify as the most robust parameters within and between individual software types. Since both parameters can be interchangeably assessed with different software solutions they may enter the clinical arena for optimized diagnostic and prognostic evaluation of cardiovascular morbidity and mortality in various pathologies.</p></div

Inter-vendor agreement on an intra- and inter-observer level for global longitudinal, global circumferential andglobal radial strain for the complete study cohort, normal subjects and patients with impaired cardiac function* based on three averaged measurements (R3).

<p>Inter-vendor agreement on an intra- and inter-observer level for global longitudinal, global circumferential andglobal radial strain for the complete study cohort, normal subjects and patients with impaired cardiac function* based on three averaged measurements (R3).</p

Inter-vendor agreement and intra-vendor reproducibility at intra- and inter-observer levels for global longitudinal, global circumferential and global radial strain based on two averaged measurements (R2).

<p>Inter-vendor agreement and intra-vendor reproducibility at intra- and inter-observer levels for global longitudinal, global circumferential and global radial strain based on two averaged measurements (R2).</p