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  • 1
    ISSN: 1432-1084
    Keywords: Key words: Heart ; Ischaemia ; MR imaging ; MR spectroscopy ; High-energy phosphates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The value of 31P-magnetic resonance spectroscopy (MRS) as a possible tool to distinguish viable from non-viable tissue after myocardial infarction was analysed in humans. Fifteen patients 3 weeks after anterior myocardial infarction were studied with breath-hold cine MRI and 3D-CSI MRS (1.5 T system). 31P-spectra were obtained from infarcted as well as non-infarcted myocardium (voxel size 25 cm3 each). Gold standard for viability was recovery of regional function, as determined by a control MRI 6 months after revascularization. Ten age-matched healthy volunteers served as control group. No significant difference was found between the phosphocreatine to adenosinetriphosphate (PCr/ATP) ratio of volunteers (SD 1.72 ± 0.31) and non-infarcted septal myocardium of patients. Cine MRI demonstrated recovery of regional function in 10 patients, i. e. 10 patients showed viable and 5 non-viable myocardium. In viable myocardium, the PCr/ATP ratio was 1.47 ± 0.38 (non-significant vs volunteers; p 〉 0.05). In the 5 patients with akinetic myocardium, PCr peaks could not be detected. Therefore, calculation of PCr/ATP ratios was not possible. However, a significant reduction of the ATP signal-to-noise ratio (SNR) was observed (2.92 ± 0.73 vs 6.68 ± 0.80; patients vs volunteers; p 〈0.05). The SNR of ATP of akinetic regions may predict recovery of function after revascularization in patients with myocardial infarction.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2102
    Keywords: Schlüsselwörter ; Herzvitien ; Klappenersatz ; MR-Imaging ; 31P-MR-Spektroskopie ; Energiestoffwechsel ; Key words ; Valve disease ; Valve replacement ; MR-imaging ; 31P-MR-spectroscopy ; Energy metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: Heart valve disease combined with left ventricular hypertrophy leads to derangements in cardiac energy metabolism, which can be detected non-invasively by 31P-MR-spectroscopy. The purpose of the present study was to examine whether the derangements in cardiac metabolism are reversible after surgical valve replacement. Patients and methods: 10 healthy volunteers and 10 patients with aortic stenosis (pressure gradients 〉60 mmHg) were included. For assessment of energy metabolism, 31P-MR spectra were obtained with a double oblique 3D-CSI technique (voxel size 25 cm3). In 5 of 10 patients, follow-up examination was performed 3 months after surgical valve replacement (SVR). Left ventricular (LV) function was analyzed by cine MRI. Results: Before SVR the myocardial phosphocreatine to adenosinetriphosphate (PCr-ATP) ratio was significantly (p=0.0002) reduced to 0.80±0.25 in patients compared to 1.65±0.21 in volunteers. 3 months after SVR, LV mass had significantly (p=0.04) decreased from 238±33 g to 206±47 g. At the same time a significant (p=0.04) increase of the PCr-ATP ratio from 0.80±0.25 to 1.28±0.22 was observed. A slight, but not significant, reduction of the phosphodiester ATP ratio was observed before SVR, with a trend towards normalization after SVR. Conclusions: After SVR, the deranged energy metabolism shows a trend towards normalization. Further follow-up is necessary to determine whether complete normalization of the energetic derangement can be observed over longer periods of time following SVR.
    Notes: Zusammenfassung Zielsetzung: Mit einer linksventrikulären Hypertrophie einhergehende Herzvitien führen zu Veränderungen des kardialen Energiestoffwechsels, die mit der 31P-MR-Spektroskopie nichtinvasiv erfasst werden können. Ziel der vorliegenden Studie war es, zu untersuchen, ob nach chirurgischem Klappenersatz eine Normalisierung des Energiestoffwechsels beobachtet werden kann. Patienten und Methode: 10 gesunde Probanden und 10 Patienten mit Aortenklappenstenose (Druckgradient 〉60 mmHg) wurden untersucht. Zur Erfassung des kardialen Energiestoffwechsels wurde eine doppelt angulierbare 3D-CSI-Technik verwendet (Voxelgröße 25 ccm). 3 Monate nach Aortenklappenersatz (AKE) erfolgte bei 5 Patienten eine Nachkontrolle. Bei den Patienten wurden zusätzlich linksventrikuläre (LV) Funktionsparameter mittels cine-MRI-Technik analysiert. Ergebnisse: Vor Klappenersatz war bei den Patienten das Phosphokreatin-Adenosintriphosphat(PCr-ATP)-Verhältnis mit 0,80±0,25 signifikant im Vergleich zu Gesunden (1,65±0,21; p=0,0002) erniedrigt. 3 Monate nach AKE konnte eine signifikante (p=0,04) Verringerung der LV-Masse von 238±33 g auf 206±47 g nachgewiesen werden. Die LV-Ejektionsfraktion änderte sich jedoch nicht wesentlich (von 61±11% auf 65±7%; p=0,22). Zur selben Zeit zeigte sich ein signifikanter (p=0,04) Anstieg des PCr-ATP-Verhältnis von 0,80±0,25 auf 1,28±0,22 an. Für das Phosphodiester-ATP-Verhältnis zeigte sich eine geringe, jedoch nicht signifikante Reduzierung vor AKE, mit einer Tendenz zum Wiederanstieg nach AKE. Schlussfolgerungen: Nach Klappenersatz ist eine Tendenz zur Normalisierung des pathologisch veränderten Energiestoffwechsels zu beobachten. Weitere Nachkontrollen sind notwendig, um zu klären, ob es zu einem späteren Zeitpunkt zu einer vollständigen Normalisierung des Energiestoffwechsels kommt.
    Type of Medium: Electronic Resource
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