Keywords:
Metabolic disorders, Diagnostic procedure, MR, Cardiac
Authors:
C. M. Berzovini1, R. Faletti2, M. Gatti2, E. Caramia2, E. Vanni1; 1Torino/IT, 2Turin/IT
Conclusion
Many publications already investigated the quantification of epicardial adipose tissue volume using imaging modalities such as CT and MRI (4; 5).
Our approach allowed us to estimate volume in a fast and reproducible way,
with some sporadic difficulties,
in particular in the delimitation of sovra-diafragmatic fat in patients who had an epicardial adipose tissue of limited thickness.
The evaluation took 8-10 minutes per patient,
in average.
Furthermore,
we used a sequence (axial SSFP) normally part of cardiac MRI protocols we use in our Institution.
Even though we need further evaluation to validate the statistical relevance of our results,
TTE showed an increase of end-systolic diameter in NAFLD patients,
albeit ejection fraction was not reduced.
This finding could be referred to a preclinical systolic dysfunction,
but MRI data analysis has not confirmed this result,
in particular in the evaluation of end-systolic volume.
With TTE,
trans-mitralic diastolic flow velocity can be measured in order to assess E/A ratio,
which represents a widely used parameter for the evaluation of diastolic function (E= first filling velocity,
which is faster and occurs during the valve opening; A= second filling velocity,
which occurs during atrial systole).
The role of MRI in the evaluation of diastolic function is still object of study.
The first and more “intuitive” attempt was to analyze volume/time curves,
but this approach has some limits,
as reported by some Authors (6; 7) (Fig.
3).
In our experience,
analyzing time/volume curves we found that the 1st/2nd filling volume ratio was relevantly different between the two examined groups.
MRI examination showed an increase in NAFLD patients in both visceral and pericardial fat tissue volume and the latter finding was confirmed by the increased thickness of pericardial fat measured with TTE.
While TTE showed signs of preclinical systolic and diastolic dysfunction,
MRI confirmed the presence of signs of diastolic dysfunction only,
by now.
Positive correlation between the volume of visceral and epicardial fat is probably linked to their common embryological origin.
Considering the pathogenesis of myocardial damage,
the paracrine action of vasoactive and metabolic regulating factors released by epicardial adipocytes may influence,
at least partially,
the development of preclinical alterations of systolic and diastolic left ventricular function,
since NAFLD patients have a more abundant epicardial fat.