Retrospective cohort study.
29 patients were included.
All patients had a systemic amyloidosis (light chain or transthyretin) histologically confirmed.
Cardiac amyloidosis was diagnosed on the presence of a myocardial hypertrophy (>12 mm) on echocardiography,
associated with a diffuse myocardial enhancement and myocardial thickening on CMR.
Diagnosis of CA was proved histologically in 4 (22%) patients.
- 12 patients with systemic amyloidosis (SA) but without CA
The absence of CA was defined as a normal echocardiography (wall thickness > 12 mm,
strain >15% in all segments),
and a normal cardiac MRI (lack of hypertrophy,
none enhancement on LGE sequences).
- 15 control patients were also included
All patients had a normal cardiac MRI with:
- No focal or global myocardial edema on STIR T2 sequences.
- Normal LV wall thickness and mass on SSFP sequences.
- Normal LVEF (>55%) and LV volumes ; no abnormalities of segmental contraction on SSFP sequences.
- Absence of abnormal myocardial enhancement on LGE sequences.
Patients were undergoing cardiac MRI because of atypical chest pain,
suspicion of hypertrophic cardiomyopathy and suspicion of arrhythmogenic right ventricle dysplasia.
All patients included were explored with a 1.5T MRI (Avanto; Siemens Medical; Erlangen; Germany).
The following sequences were systematically performed:
- SSFP sequences,
acquired before and 3 to 5 minutes after injection of 0.2 mmol/Kg of gadolinium:
- In a middle short axis plane.
- In the four-chamber plane.
- Parameters of SSFP sequences were as follows: TR/TE,
2.8/1.4; flip angle,
82°deg; matrix size,
192 x 192; FOV,
300 x 270 mm; slice thickness,
6 mm.
- LGE sequence acquired 10 minutes after injection:
- Parameters of LGE sequences were as follows: TR/TE,
3.9/1.4; mean inversion recovery time,
220 +/- 50 ms; flip angle,
10°deg; matrix size,
192 x 192; FOV,
300 x 270 mm; number of sections,
12; slice thickness,
6 mm.
- A TI scouting sequence was systematically performed before LGE sequence
Image analysis was performed on a dedicated console (Leonardo; Siemens Medical) by one operator with 1 year experience in cardiac imaging.
Left ventricular myocardial signal intensity (SI) was measured using a ROI drawn manually (encompassing the whole myocardium) on the SSFP images acquired before and after injection.
This measurement was performed on the short axis view and on the four chamber view on end diastolic images.
Attention was paid to avoid subendocardial and subepicardial areas.
Percentage of myocardial enhancement was calculated between pre and post contrast measures of signal intensities.
Left ventricular ejection fraction (LVEF) and myocardial thickness were measured using a dedicated software (Argus; Siemens Medical System).
Statistical analysis :
Results are presented as mean values +/- standard deviation.
ANOVA test with post-hoc Bonferroni test was used to compare data of the 3 groups of patients.
The percentage of myocardial enhancement were compared using a Pearson’s test.