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A Comprehensive Evaluation of Left Atrial Performance Using Volumetric Analysis, Strain, and Strain Rate Imaging
No full textMINOCA—myocardial infarction with nonobstructive coronary arteries
No full textHintergrund
Der Myokardinfarkt mit nichtobstruktiven Koronararterien (MINOCA) betrifft ca. 5–10 % aller akuten Myokardinfarkte.
Ziel der Arbeit
Der vorliegende Artikel erläutert die Rolle der kardialen Magnetresonanztomographie (MRT) bei der Abklärung der Arbeitsdiagnose MINOCA.
Material und Methoden
Aktuelle Leitlinienempfehlungen zum Einsatz der kardialen MRT bei Verdacht auf MINOCA werden zusammengefasst. Klinische Fallbeispiele mit typischen Befunden in der kardialen MRT werden präsentiert.
Ergebnisse
Im Jahr 2019 wurde von der American Heart Association eine überarbeitete Definition für den Begriff MINOCA vorgestellt, welche zuletzt auch von der Leitlinie zum akuten Koronarsyndrom ohne persistierende ST-Strecken-Hebungen (NSTE-ACS) der Europäischen Gesellschaft für Kardiologie übernommen wurde. Die Leitlinie empfiehlt die Durchführung einer kardialen MRT bei allen MINOCA-Fällen ohne offensichtliche Ursache (Klasse-1B-Indikation).
Diskussion
Die kardiale MRT erlaubt mit hoher Zuverlässigkeit eine Differenzierung zwischen ischämischen und nichtischämischen Myokardschädigungen und ist heutzutage zentraler Bestandteil in der Aufarbeitung der Arbeitsdiagnose MINOCA.Background
Myocardial infarction with nonobstructive coronary arteries (MINOCA) accounts for 5–10% of all presentations of acute myocardial infarction.
Objectives
To outline the role of cardiovascular magnetic resonance (CMR) in patients with suspected MINOCA.
Materials and methods
Current guidelines for the use of CMR in suspected MINOCA are summarized. Clinical cases with typical CMR findings are presented.
Results
In 2019, the American Heart Association published a revised definition of the term MINOCA, which was recently adopted in the European Society of Cardiology 2020 guidelines on acute coronary syndromes without persistent ST-segment elevation (NSTE-ACS). The guidelines indicate that a CMR is recommended (class 1B) in all MINOCA cases with no obvious cause.
Conclusion
The major strength of CMR imaging is to differentiate nonischemic from ischemic etiologies of myocardial injury. This makes CMR the most important noninvasive diagnostic tool for the differential diagnosis of patients with suspected MINOCA
Left atrial physiology and pathophysiology: Role of deformation imaging
No full textThe left atrium (LA) acts as a modulator of left ventricular (LV) filling. Although there is considerable evidence to support the use of LA maximum and minimum volumes for disease prediction, theoretical considerations and a growing body of literature suggest to focus on the quantification of the three basic LA functions: (1) Reservoir function: collection of pulmonary venous return during LV systole; (2) Conduit function: passage of blood to the left ventricle during early LV diastole; and (3) Contractile booster pump function (augmentation of ventricular filling during late LV diastole. Tremendous advances in our ability to non-invasively characterize all three elements of atrial function include speckle tracking echocardiography (STE), and more recently cardiovascular magnetic resonance myocardial feature tracking (CMR-FT). Corresponding imaging biomarkers are increasingly recognized to have incremental roles in determining prognosis and risk stratification in cardiac dysfunction of different origins. The current editorial introduces the role of STE and CMR-FT for the functional assessment of LA deformation as determined by strain and strain rate imaging and provides an outlook of how this exciting field may develop in the future
Cardiovascular Magnetic Resonance Myocardial Feature Tracking: Concepts and Clinical Applications
No full textHeart failure-induced cardiovascular morbidity and mortality constitute a major health problem worldwide and result from diverse pathogeneses, including coronary artery disease, nonischemic cardiomyopathies, and arrhythmias. Assessment of cardiovascular performance is important for early diagnosis and accurate management of patients at risk of heart failure. During the past decade, cardiovascular magnetic resonance myocardial feature tracking has emerged as a useful tool for the quantitative evaluation of cardiovascular function. The method allows quantification of biatrial and biventricular mechanics from measures of deformation: strain, torsion, and dyssynchrony. The purpose of this article is to review the basic principles, clinical applications, accuracy, and reproducibility of cardiovascular magnetic resonance myocardial feature tracking, highlighting the prognostic implications. It will also provide an outlook on how this field might evolve in the future
Left Atrial Performance in the Course of Hypertrophic Cardiomyopathy
No full textOBJECTIVES: Hypertrophic cardiomyopathy (HCM) is associated with left atrial (LA) functional abnormalities. The determinants and the degree of LA dysfunction in the course of HCM are not fully understood. We aimed to characterize LA mechanics in HCM, according to the extent of left ventricular (LV) hypertrophy and fibrosis.METHODS AND RESULTS: Seventy-three HCM patients and 23 age- and sex-matched controls underwent cardiovascular magnetic resonance imaging including late gadolinium enhancement (LGE). LA reservoir, conduit, and contractile functions were quantified by fractional volume changes and cardiovascular magnetic resonance feature-tracking-derived strain and strain rate. In multivariable regression, LA mechanics were associated with the extent of LV LGE (P = 0.033 to P < 0.001), but not with the LV mass extent or maximum wall thickness (P = 0.108 to P = 0.964). Left atrial function decreased according to the increase in extent of LV fibrosis (non-LGE; mild LGE ≤ 10%; intermediate LGE 11%-19%; severe LGE ≥ 20%). Compared with healthy controls, LA conduit function was impaired in HCM with no LGE already (LA emptying fraction conduit: 32% ± 7% vs 26 ± 14, P = 0.037). Conversely, LA contractile booster pump function was impaired in HCM with severe LGE only (LA emptying fraction booster: 40% ± 8% vs 20% ± 10%, P < 0.001; for controls vs LGE ≥ 20%, respectively).CONCLUSIONS: Left atrial functional abnormalities are associated with LV fibrosis, but not with LV hypertrophy. While LA conduit function is impaired in early HCM stages as represented by mild or absent LV fibrosis, LA contractile function is impaired later in the course of disease progression as demonstrated by the presence of severe LV fibrosis only. These novel markers of LA performance may potentially proof useful for disease staging and early detection of cardiac deterioration.</p
Real-time phase-contrast flow MRI of the ascending aorta and superior vena cava as a function of intrathoracic pressure (Valsalva manoeuvre)
No full textObjective: Real-time phase-contrast flow MRI at high spatiotemporal resolution was applied to simultaneously evaluate haemodynamic functions in the ascending aorta (AA) and superior vena cava (SVC) during elevated intrathoracic pressure (Valsalva manoeuvre). Methods: Real-time phase-contrast flow MRI at 3 T was based on highly undersampled radial gradient-echo acquisitions and phase-sensitive image reconstructions by regularized non-linear inversion. Dynamic alterations of flow parameters were obtained for 19 subjects at 40-ms temporal resolution, 1.33-mm in-plane resolution and 6-mm section thickness. Real-time measurements were performed during normal breathing (10 s), increased intrathoracic pressure (10 s) and recovery (20 s). Results: Real-time measurements were technically successful in all volunteers. During the Valsalva manoeuvre (late strain) and relative to values during normal breathing, the mean peak flow velocity and flow volume decreased significantly in both vessels (p < 0.001) followed by a return to normal parameters within the first 10 s of recovery in the AA. By contrast, flow in the SVC presented with a brief (1-2 heartbeats) but strong overshoot of both the peak velocity and blood volume immediately after pressure release followed by rapid normalization. Conclusion: Real-time phase-contrast flow MRI may assess cardiac haemodynamics non-invasively, in multiple vessels, across the entire luminal area and at high temporal and spatial resolution. Advances in knowledge: Future clinical applications of this technique promise new insights into haemodynamic alterations associated with pre-clinical congestive heart failure or diastolic dysfunction, especially in cases where echocardiography is technically compromised.DFG [LO 1773/1-1
Combination of vertebral bone quality scores from different magnetic resonance imaging sequences improves prognostic value for the estimation of osteoporosis
No full textBackground Context
Recent findings revealed a correlation between vertebral bone quality based on T1-weighted (VBQT1) magnetic resonance imaging (MRI) and volumetric bone mass density (vBMD) measured using quantitative computerized tomography. The coherence of VBQ for other MRI sequences, such as T2 or short tau inversion recovery (STIR), has not been examined. The combination of different VBQs has not been studied.
Purpose
The aims of the study were to confirm the correlation between VBQT1 and vBMD and to examine VBQs from other MRI sequences and their combination with vBMD.
Study Design/Setting
This was a retrospective cross-sectional study.
Patient Sample
The sample consisted of patients older than 18 years, who received treatment at a level-one university spine center of the German Spine Society for degenerative or traumatic reasons in 2017–2021.
Outcome Measures
The outcome measures were the correlation of VBQs from different MRI sequences with vBMD and the association of VBQs with osteopenia/osteoporosis.
Methods
Patients’ VBQ was calculated based on the signal intensities of the vertebral bodies L1–4 in T1-, T2-, and STIR-weighted MRI. The VBQ was standardized according to the signal intensity of the cerebrospinal fluid. The vBMD was determined using data from a calibrated scanner (SOMATOM Definition AS+) and processed with CliniQCT (Mindways Software, Inc., USA). Groups were divided according to vBMD into the following groups: (I) osteoporosis/osteopenia (< 120 mg/m3) and (II) healthy (≥120 mg/m3). An analysis of the correlation between various VBQs and vBMD as well as receiver operating characteristic (ROC) and binary regression analyses were performed for the prediction of osteoporosis/osteopenia.
Results
We included 136 patients (women: 56.6%) in the study (69.7 ± 15.0 years). According to vBMD, 108 patients (79.4%) had osteoporosis/osteopenia. Women were affected significantly more often than men (p = .045) and had significantly higher VBQT1 and VBQT2 values than men (VBQT1: p = .048; VBQT2: p = .013). VBQT1 and VBQT2 values were significantly higher in patients with osteoporosis/osteopenia than in healthy persons (VBQT1: p<.001; VBQT2: p = .025). VBQT1 and VBQT2 were significantly negatively correlated with vBMD with a moderate effect size (p<.001), while VBQSTIR was not significantly correlated with vBMD, although it showed a positive coherence. The combination of different VBQs in terms of VBQT1 × VBQT2 / VBQSTIR distinctly increased the effect size of the negative correlation with vBMD compared to VBQ alone. A cutoff value for VBQT1 × VBQT2 / VBQSTIR of 2.9179 achieved a sensitivity of 80.0%, a specificity of 75.0%, and an area under the curve (AUC) of 0.775 for the determination of osteoporosis. The mathematical model derived from the binary logistic regression showed an excellent AUC of 0.846.
Conclusions
This study confirms a significant correlation between VBQT1 and vBMD. The combination of VBQs from different MRI sequences enhances the prognostic value of VBQ for the determination of osteoporosis. While safe clinical application of VBQ for the determination of osteoporosis requires further validation, VBQ might offer opportunistic estimation for further diagnostics
Echtzeit-Cardio-MRT-Phasenkontrast-Flussmessungen mit dem Valsalva- und Müllermaneuver als Stresstest
No full textZiele: Hochaufgelöste Echtzeit-Phasenkontrast-MRT-Flussmessungen wurden u.a. in der Aorta ascendens angewendet. Die MRT-Technik basiert auf einer stark unterabgetasteten radialen FLASH-Sequenz und anschließender Bildrekonstruktion mit nicht-linearer Inversion. Normale Flussmessungen und Flusswerte wurden während physiologischer Stresstests wie dem Valsalva- (erhöhter intrathorakaler Druck) und Müllermaneuver (erniedrigter intrathorakaler Druck) bei gesunden Probanden durchgeführt. Methode: Der Blutfluss wurde in den großen thorakalen Gefäßen gemessen, In-plane 1.2 mm, Schichtdicke 6 mm und realer Echtzeitauflösung von 40 ms. Die TR betrug 3.44 ms, TE 2.76 ms. Alle Scans wurden in einem 3T MRT durchgeführt. Das EKG-Signal wurde zur besseren Zuordnung der Herzphasen mit aufgezeichnet. Die Echtzeitmessungen wurden in Ruhe sowie 10 s Valsalva und 10 s Müllermanöver durchgeführt. Die Bildanalyse erfolgte in einer modifizierten Standardsoftware QFlow, Medis, Leiden NL. Ergebnis: Echtzeitflussmessungen konnten erfolgreich bei allen Probanden (n = 10) durchgeführt werden. Wir beobachteten unter Stressbedingungen einen Abfall des Blutflusses, der Maximalgeschwindigkeit und der kardialen Auswurfleistung sowie eine Herzfrequenzzunahme unter Valsalva- und Müllermaneuver in der Aorta ascendens. Zu Beginn der Stressmaneuver stieg der Blutfluss und die Auswurfleitung initial an unter erhöhten und reduzierten intrathorakalen Druckverhältnissen, gefolgt von einer kontinuierlichen 10 s dauernden Abnahme. Anschließend folgte wieder eine Normalisierung nach Stressbeendigung. Schlussfolgerung: Hoch aufgelöste Echtzeit-MRT-Flussmessungen sind sehr gut dafür geeignet um physiologische Blutflussveränderungen während dem Valsalva- und Müllermaneuver bei Stressbedingungen darzustellen. Die Ergebnisse stimmen mit Beobachtungen aus der Echokardiografie überein. Mit dieser neuen Echtzeit-Flusstechnik gibt es neue Möglichkeiten um pathologische Veränderungen am Herzen darzustellen wie bei angeborenen Herzfehlern oder Kardiomyopathien
Impaired Exercise Tolerance after Repair of Tetralogy of Fallot—Insights from Real-Time Cardiovascular Magnetic Resonance Imaging
No full textObjectives: Surgical correction of tetralogy of Fallot (cTOF) frequently results in residual pulmonary valve stenosis/regurgitation and impaired right ventricular (RV) function. Reduced capacity in cardiopulmonary exercise testing (CPET) in cTOF patients, however, cannot entirely be explained by these findings. The present study sought to assess biventricular cardiac function during exercise using a comprehensive CPET and real-time cardiovascular magnetic resonance exercise testing (CMR-ET) protocol. Methods: A total of 33 cTOF patients (age 35.6 + 11.3 years) and 33 matched healthy controls (age 34.4 +11.9 years) underwent CPET and CMR-ET. Real-time SSFP and phase contrast sequences were obtained during supine bicycle in scanner CMR-ET at 50, 70, and 90 W. RV and LV volumetry and flow quantification of the pulmonary trunk (Qp) were performed. Correlation between CPET and CMR-ET parameters was investigated using Spearman’s rank test. Results: Exercise capacity on CPET was significantly lower in cTOF than in healthy controls. With incremental exercise levels on CMR-ET, cTOF patients failed to recruit both RV and LV functions and Qp (Table 1). Correlation analysis revealed higher CPET values in those cTOF patients with higher Qp (Qp 90 W vs. VE/VCO2%: r = −0.519, p < 0.05), higher LV EDVi (LV EDVi at 50 W vs. VO2% r = 0.452, p < 0.05) and less change in LV EF (LV-EF at 90 W vs. W % r = −0.463, p < 0.05). No correlation was found with RV EF. Significant RV–LV interaction was observed at 70 W CMR-ET (correlation of RV and LF EF r = 0.52, p < 0.05). Conclusion: Compared with healthy controls, cTOF patients displayed impaired exercise capacity due to a lack in recruitment of both RV function and pulmonary blood flow but also of LV function. RV and LV functions during exercise showed significant interdependence. CMR-ET may be a helpful tool in the assessment of cardiac function in cTOF patients
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