MRI
Which late gadolinium enhancement pattern is seen in the images?
There is a focal, patchy subepicardial pattern.
What cut-off values are used regarding global oedema and early gadolinium enhancement (EGE) if myocarditis is suspected?
Signal intensity and enhancement ratios between myocardium and skeletal muscle should be ≥2 (for myocardial oedema) and ≥4 for early gadolinium enhancement (EGE) to be considered a sign of myocarditis.
What needs to be considered on the acquisition of T1wBB and STIR images, if one aims for assessing global oedema or early gadolinium enhancement (EGE)?
It is recommended that those sequences are acquired with the body coil.
Which cardiac pathologies can lead to increased native T1 and ECV values?
A whole lot, among them, myocardial infarction, myocarditis, amyloidosis, Tako-tsubo cardiomyopathy and every clinical entity which can lead to fibrosis.
What criteria need to be fulfilled for the diagnosis of myocarditis?
According to the updated version of the Lake Louise criteria (2018), a cardiac MRI scan provides strong evidence for myocardial inflammation if at least one T2-based criterion for myocardial oedema and one T1-based criterion for associated non-ischaemic myocardial injury is positive. There are also two supportive criteria, being pericarditis and systolic left-ventricular dysfunction.
Findings:
Heart rate: 67 bpm, haematocrit: 0.38
Image quality: some respiratory artifacts, otherwise no limitations
Morphology and functional analysis:
- LV-EDVI: 71 mL/m²
- LV-ESVI: 27 mL/m²
- LV-SVI: 43 mL/m²
- LV-EF: 61%
- cardiac output: 5.3 L/min
- cardiac index: 2.9 L/min/m²
- LV-ED wall + papillary mass: 99 g
- septum thickness: 10 mm
No regional left ventricular wall motion abnormalities.
Visually normal atrial size.
No significant cardiac valve pathology detected.
No intercavitary thrombi found.
Myocardial tissue properties (according to Lake Louise criteria II)1:
Regional myocardial oedema in the apical segments best visible in the lateral wall.
Patchy intramyocardial and subepicardial late gadolinium enhancement (LGE) visible in the apical lateral and midventricular antero- and inferolateral segments.
T1 mapping: native T1 >1100 ms [948-1060 ms*], extracellular volume (ECV) 32-35%
* native T1 reference range based on local data
Minimal pericardial enhancement without thickening, adjacent to the left ventricular free wall.
No pericardial effusion.
Small bilateral pleural effusions.
Impression:
Cardiac MRI findings are consistent with acute inflammatory changes of the myocardium or acute myocarditis.