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  • 1
    In: European Radiology, Springer Science and Business Media LLC, Vol. 33, No. 9 ( 2023-04-19), p. 6299-6307
    Abstract: In cardiac transplant recipients, non-invasive allograft surveillance for identifying patients at risk for graft failure remains challenging. The fat attenuation index (FAI) of the perivascular adipose tissue in coronary computed tomography angiography (CCTA) predicts outcomes in coronary artery disease in non-transplanted hearts; however, it has not been evaluated in cardiac transplant patients. Methods We followed 39 cardiac transplant patients with two or more CCTAs obtained between 2010 and 2021. We performed FAI measurements around the proximal 4 cm segments of the left anterior descending (LAD), right coronary artery (RCA), and left circumflex artery (LCx) using a previously validated methodology. The FAI was analyzed at a threshold of − 30 to − 190 Hounsfield units. Results FAI measurements were completed in 113 CCTAs, obtained on two same-vendor CT models. Within each CCTA, the FAI values between coronary vessels were strongly correlated (RCA and LAD R  = 0.67 ( p   〈  0.0001), RCA and LCx R  = 0.58 ( p   〈  0.0001), LAD and LCx R  = 0.67 ( p   〈  0.0001)). The FAIs of each coronary vessel between the patient’s first and last CCTA completed at 120 kV were also correlated (RCA R  = 0.73 ( p   〈  0.0001), LAD R  = 0.81 ( p   〈  0.0001), LCx R  = 0.55 ( p  = 0.0069). Finally, a high mean FAI value of all three coronary vessels at baseline (mean ≥  − 71 HU) was predictive of cardiac mortality or re-transplantation, however, not predictive of all cause-mortality. Conclusion High baseline FAI values may identify a higher-risk cardiac transplant population; thus, FAI may support the implementation of CCTA in post-transplant surveillance. Key Point • Perivascular fat attenuation measured with coronary CT is feasible in cardiac transplant patients and may predict cardiac mortality or need for re-transplantation .
    Type of Medium: Online Resource
    ISSN: 1432-1084
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 1472718-3
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  • 2
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2021
    In:  European Radiology Vol. 31, No. 4 ( 2021-04), p. 1883-1893
    In: European Radiology, Springer Science and Business Media LLC, Vol. 31, No. 4 ( 2021-04), p. 1883-1893
    Abstract: Longitudinal hemodynamic follow-up is important in the management of pulmonary hypertension (PH). This study aimed to evaluate the potential of MR 4-dimensional (4D) flow imaging to predict changes in the mean pulmonary arterial pressure (mPAP) during serial investigations. Methods Forty-four adult patients with PH or at risk of developing PH repeatedly underwent routine right heart catheterization (RHC) and near-term MR 4D flow imaging of the main pulmonary artery. The duration of vortical blood flow along the main pulmonary artery was evaluated from MR 4D velocity fields using prototype software and converted to an MR 4D flow imaging-based mPAP estimate (mPAP MR ) by a previously established model. The relationship of differences between RHC-derived baseline and follow-up mPAP values (ΔmPAP) to corresponding differences in mPAP MR (ΔmPAP MR ) was analyzed by means of regression and Bland-Altman analysis; the diagnostic performance of ΔmPAP MR in predicting mPAP increases or decreases was investigated by ROC analysis. Results Areas under the curve for the prediction of mPAP increases and decreases were 0.92 and 0.93, respectively. With the natural cutoff ΔmPAP MR = 0 mmHg, mPAP increases (decreases) were predicted with an accuracy, sensitivity, and specificity of 91% (91%), 85% (89%), and 94% (92%), respectively. For patients in whom 4D flow allowed a point estimate of mPAP (mPAP 〉 16 mmHg), ΔmPAP MR correlated strongly with ΔmPAP ( r = 0.91) and estimated ΔmPAP bias-free with a standard deviation of 5.1 mmHg. Conclusions MR 4D flow imaging allows accurate non-invasive prediction and quantification of mPAP changes in adult patients with PH or at risk of developing PH. Trial registration ClinicalTrials.gov identifier: NCT00575692 and NCT01725763 Key Points • MR 4D flow imaging allows accurate non-invasive prediction of mean pulmonary arterial pressure increases and decreases in adult patients with or at risk of developing pulmonary hypertension. • In adult patients with mean pulmonary arterial pressure 〉 16 mmHg, MR 4D flow imaging allows estimation of longitudinal mean pulmonary arterial pressure changes without bias with a standard deviation of 5.1 mmHg.
    Type of Medium: Online Resource
    ISSN: 0938-7994 , 1432-1084
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 1472718-3
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  • 3
    In: Journal of Magnetic Resonance Imaging, Wiley, Vol. 53, No. 3 ( 2021-03), p. 755-765
    Abstract: Quantification of myocardial blood flow (MBF) from dynamic contrast‐enhanced (DCE) MRI can be performed using a signal intensity model that incorporates T 1 values of blood and myocardium. Purpose To assess the impact of T 1 values on pixelwise MBF quantification, specifically to evaluate the influence of 1) study population‐averaged vs. subject‐specific, 2) diastolic vs. systolic, and 3) regional vs. global myocardial T 1 values. Study Type Prospective. Subjects Fifteen patients with chronic coronary heart disease. Field Strength/Sequence 3T; modified Look–Locker inversion recovery for T 1 mapping and saturation recovery gradient echo for DCE imaging, both acquired in a mid‐ventricular short‐axis slice in systole and diastole. Assessment MBF was estimated using Fermi modeling and signal intensity nonlinearity correction with different T 1 values: study population‐averaged blood and myocardial, subject‐specific systolic and diastolic, and segmental T 1 values. Myocardial segments with perfusion deficits were identified visually from DCE series. Statistical Tests The relationships between MBF parameters derived by different methods were analyzed by Bland–Altman analysis; corresponding mean values were compared by t ‐test. Results Using subject‐specific diastolic T 1 values, global diastolic MBF was 0.61 ± 0.13 mL/(min·g). It did not differ from global MBF derived from the study population‐averaged T 1 ( P = 0.88), but the standard deviation of differences was large (0.07 mL/(min·g), 11% of mean MBF). Global diastolic and systolic MBF did not differ ( P = 0.12), whereas global diastolic MBF using systolic (0.62 ± 0.13 mL/(min·g)) and diastolic T 1 values differed ( P   〈  0.05). If regional instead of global T 1 values were used, segmental MBF was lower in segments with perfusion deficits (bias = −0.03 mL/(min·g), −7% of mean MBF, P   〈  0.05) but higher in segments without perfusion deficits (bias = 0.01 mL/(min·g), 1% of mean MBF, P   〈  0.05). Data Conclusion Whereas cardiac phase‐specific T 1 values have a minor impact on MBF estimates, subject‐specific and myocardial segment‐specific T 1 values substantially affect MBF quantification. Level of Evidence 3 Technical Efficacy Stage 3
    Type of Medium: Online Resource
    ISSN: 1053-1807 , 1522-2586
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1497154-9
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  • 4
    In: European Journal of Radiology, Elsevier BV, Vol. 141 ( 2021-08), p. 109756-
    Type of Medium: Online Resource
    ISSN: 0720-048X
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 2005350-2
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  • 5
    Online Resource
    Online Resource
    Georg Thieme Verlag KG ; 2020
    In:  RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren Vol. 192, No. 03 ( 2020-03), p. 246-256
    In: RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, Georg Thieme Verlag KG, Vol. 192, No. 03 ( 2020-03), p. 246-256
    Abstract: Hintergrund Die kardiale Magnetresonanztomografie (MRT) stellt sowohl in der Beurteilung der Herzfunktion als auch zur nichtinvasiven Gewebsanalyse des Myokards in vielen klinischen Fragestellungen die Referenz-Standard-Methode dar. Speziell die Quantifizierung kardialer Parameter nimmt eine immer zentralere diagnostische und differenzialdiagnostische Rolle ein. Im vorliegenden Review sollen etablierte und vielversprechende neue quantitative Herz-MRT-Parameter der klinischen Routine zusammengefasst, ihre Zusammenhänge beschrieben sowie ihre Abhängigkeiten von substanziellen Einflussfaktoren dargestellt werden. Methode Die Übersichtsarbeit basiert auf einer PubMed-Literaturrecherche zu den Begriffen „cardiac magnetic resonance“ und „quantification“, „recommendations“, „quantitative evaluation/assessment“, „reference method“, „reference/normal values“, „pitfalls“ sowie „artifacts“ innerhalb des Publikationszeitraums 2000–2019. Ergebnisse und Schlussfolgerung Funktionelle, Phasenkontrast- und Perfusionsbildgebung sowie Relaxationszeit-Kartierung ermöglichen die Erfassung einer Vielzahl quantitativer Herz-MRT-Parameter. Diese erlauben eine über die visuelle Beurteilung von Herz-MRT-Bildern hinausgehende Charakterisierung der Funktion, Morphologie und Perfusion des Herzens, sei es im Vergleich zu Normalwerten oder im Therapieverlauf. Bei der Interpretation ausgewerteter Herz-MRT-Parameter in der klinischen Routine muss allerdings zunehmend auf Standardisierung geachtet werden, da Aufnahmetechniken und Auswertealgorithmen quantitative Ergebnisse maßgeblich – jedoch mitunter nicht unmittelbar erkennbar – beeinflussen können. Kernaussagen:  Zitierweise
    Type of Medium: Online Resource
    ISSN: 1438-9029 , 1438-9010
    RVK:
    Language: English
    Publisher: Georg Thieme Verlag KG
    Publication Date: 2020
    detail.hit.zdb_id: 2031079-1
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  • 6
    In: Magnetic Resonance in Medicine, Wiley, Vol. 84, No. 6 ( 2020-12), p. 3396-3408
    Abstract: To present and validate a method for automated extraction and analysis of the temporal evolution of the mitral valve (MV) vortex ring from MR 4D‐flow data. Methods The proposed algorithm uses the divergence‐free part of the velocity vector field for Q criterion‐based identification and tracking of MV vortex ring core and region within the left ventricle (LV). The 4D‐flow data of 20 subjects (10 healthy controls, 10 patients with ischemic heart disease) were used to validate the algorithm against visual analysis as well as to assess the method’s sensitivity to manual LV segmentation. Quantitative MV vortex ring parameters were analyzed with respect to both their differences between healthy subjects and patients and their correlation with transmitral peak velocities. Results The algorithm successfully extracted MV vortex rings throughout the entire cardiac cycle, which agreed substantially with visual analysis (Cohen’s kappa = 0.77). Furthermore, vortex cores and regions were robustly detected even if a static end‐diastolic LV segmentation mask was applied to all frames (Dice coefficients 0.82 ± 0.08 and 0.94 ± 0.02 for core and region, respectively). Early diastolic MV vortex ring vorticity, kinetic energy and circularity index differed significantly between healthy controls and patients. In contrast to vortex shape parameters, vorticity and kinetic energy correlated strongly with transmitral peak velocities. Conclusion An automated method for temporal MV vortex ring extraction demonstrating robustness with respect to LV segmentation strategies is introduced. Quantitative vortex parameter analysis indicates importance of the MV vortex ring for LV diastolic (dys)function.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 1493786-4
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