Age Dependency of Myocardial Triglyceride Content: A 3T High-Field ¹H-MR Spectroscopy Study

Abstract

Purpose: The role of myocardial triglyceride (mTG) content in the aging human heart is not entirely understood. The aim of this study was to measure concentrations of mTG content from healthy volunteers and to determine the association between age, mTG content and systolic heart function. Furthermore, the technical stability of the ¹H-magnetic resonance spectroscopy (¹H-MRS) and the reliability of peak evaluation at 3 T were evaluated.

Materials and Methods: The total study population of 47 healthy volunteers was divided into 4 age classes, according to the age of the subjects (1^st cohort 20 – 29 years (yrs.), n = 20; 2^nd cohort 30 – 39 yrs., n = 10; 3^rd cohort 40 – 49 yrs., n = 9; 4^th cohort 50 – 60 yrs., n = 8). Cardiac MRI and double triggered ¹H-MRS of the myocardium were consecutively performed using a 3 T scanner. Each participant underwent spectroscopic measurements twice in the same investigation.

Results: mTG content increases with age. The correlation of age and mTG is minimal (r = 0.48; p < 0.001). The following age-averaged mTG content values expressed as % of mTG signal compared to the water signal were determined for each cohort: 1^st cohort 0.25 % (± 0.17); 2^nd cohort 0.48 % (± 0.30); 3^rd cohort 0.48 % (± 0.18); 4^th cohort 0.77 % (± 0.70). There was no significant correlation (r = 0.04; p = n.s.) between LV mass and mTG content in healthy volunteers. Within our cohorts, no effects of age or mTG content on systolic heart function were seen (r = – 0.01; p = n.s.). The intraclass correlation coefficient of spectroscopic measurements was high (r = 0.965; p < 0.001).

Conclusion: Myocardial TG content increases with age. The normal age-dependent concentration ranges of myocardial lipid metabolites reported in this study may be helpful for the correction of acquired ¹H-MRS data in patients when evaluating metabolic and cardiovascular diseases in future magnetic resonance spectroscopy studies.

Key Points:

• ¹H-MRS enables noninvasive myocardial lipid determination

• Double triggered ¹H-MRS of the heart at 3 T is a technically stable and reliable method

• Myocardial triglyceride content increases with age

• Myocardial triglyceride content is independent of LV mass and systolic function

Citation Format:

• Petritsch B, Gassenmaier T, Kunz AS et al. Age Dependency of Myocardial Triglyceride Content: A 3T High-Field ¹H-MR Spectroscopy Study. Fortschr Röntgenstr 2015; 187: 1016 – 1021

Zusammenfassung

Ziel: Die Rolle myokardialer Triglyceride (mTG) im alternden menschlichen Herz wurde bis dato noch nicht ausführlich untersucht. Das Ziel dieser Studie war die Konzentration von mTG an gesunden Probanden zu messen und Zusammenhänge zwischen Alter, mTG-Konzentration und systolischer Herzfunktion aufzuzeigen. Des Weiteren sollte die technische Zuverlässigkeit der Protonen-MR-Spektroskopie (¹H-MRS) am Herzen bei einer Feldstärke von 3 T untersucht werden.

Material und Methoden: Insgesamt 47 gesunde Probanden wurden entsprechend ihres jeweiligen Alters in 4 Kohorten unterteilt (1. Kohorte 20 – 29 Jahre, n = 20; 2. Kohorte 30 – 39 Jahre, n = 10; 3. Kohorte 40 – 49 Jahre, n = 9; 4. Kohorte 50 – 51 Jahre, n = 8). Kardiale MRT und doppelt getriggerte ¹H-MRS des Myokards wurden unmittelbar nacheinander an einem 3 T Gerät durchgeführt. Von jedem Teilnehmer wurden in einem Untersuchungsgang zwei spektroskopische Messungen akquiriert.

Ergebnisse: Der mTG Gehalt korreliert mit dem Lebensalter (r = 0,48; p < 0,001). Folgende altersgemittelte mTG Werte (angegeben als mTG/Wasser-Resonanz-Verhältnis in Prozent) wurden ermittelt: 1 Kohorte 0,25 % (± 0,17); 2 Kohorte 0,48 % (± 0,30); 3 Kohorte 0,48 % (± 0,18); 4 Kohorte 0,77 % (± 0,70). Die mTG-Konzentration in Gesunden ist unabhängig von der LV-Masse (r = 0,04; p = n.s.) und der systolischen Herzfunktion (r = – 0,01; p = n.s.) Die technische Zuverlässigkeit der ¹H-MRS des Herzens bzw. die Reproduzierbarkeit der mTG Werte waren hoch (r = 0,965; p < 0,001).

Schlussfolgerung: Die myokardiale TG-Konzentration bei Gesunden nimmt mit dem Alter zu. Die ermittelten mTG-Konzentrationen aus dieser Studie könnten als Orientierungswerte für Normalkollektive in zukünftigen ¹H-MRS Studien herangezogen werden.

Kernaussagen:

• ¹H-MRS ermöglicht die nicht invasive myokardiale Lipid Bestimmung

• Die doppelt getriggerte ¹H-MRS des Herzens bei 3 T ist eine technisch zuverlässig Methode

• Die myokardiale Triglyerid-Konzentration steigt mit dem Lebensalter

• Die myokardiale Triglycerid-Konzentration ist unabhängig von der LV Masse und LV Funktion

Key words

MR spectroscopy - myocardial triglyceride content - age dependency

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