Myocarditis

Case contributed by Joachim Feger

Presentation

Chest pain elevated troponin T: 1.4 µg/L, CK 19.2 µmol/L, LDH 6.3 µmol/L and C-reactive protein (CRP): 17 mg/L. Mildly decreased cardiac function on echo.

Patient Data

Age: 20 years
Gender: Male
mri

Findings:

Heart rate: 65 bpm, hematocrit: 0.42

Image quality: mild respiratory artifacts, otherwise no limitations

Morphology and functional analysis:

  • LV-EDVI: 90 mL/m²
  • LV-ESVI: 43 mL/m²
  • LV-SVI: 46 mL/m²
  • LV-EF: 52%
  • cardiac output: 5.7 L/min
  • cardiac index: 3.0 L/min/m²
  • LV-ED wall + papillary mass: 77 g
  • septum thickness: 8 mm

No regional left ventricular wall motion abnormalities.

Visually normal atrial size.

No significant cardiac valve pathology.

No intracavitary thrombi.

Cardiac tissue characterization (according to Lake Louise criteria II)1:

Regional myocardial edema is visible in the lateral wall from anterolateral to inferior and basal to apical.

Subepicardial and patchy intramyocardial late gadolinium enhancement (LGE) visible in the lateral and inferior segments from basal to apical.

T1 mapping: native T1 >1100 ms [948-1060 ms*], extracellular volume (ECV) 34-40% in lateral and inferior segments

T2 mapping: 65-70 ms [42-56 ms*]

* native 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 whole lateral wall of the myocardium or acute myocarditis.

Annotated image

T2 black-blood/STIR:

Focal myocardial edema can be seen in the lateral and inferior segments from basal to apical (blue arrowheads). 

Myocardial edema can be also assessed by calculating the T2 signal intensity ratio between myocardium and skeletal muscle within the same image.

T1 mapping:

Increased native T1 in the basal, midventricular and apical lateral and inferior segments is measured and displayed on a color-map T1 >1150 ms, z-score of >5 (based on local data).

The T1 values in the septum are within normal limits of the local reference range.

T2 mapping

Increased T2 values are measured in the basal, midventricular and apical lateral and inferior wall as another proof of myocardial edema in those segments.

The T2 values in the septum are within normal limits of the local reference range.

Late gadolinium enhancement (LGE):

Patchy intramyocardial and focal subepicardial late gadolinium enhancement can be seen on IR-GE images (red arrowheads) which is a characteristic pattern in myocarditis and reflects myocardial injury or myocardial necrosis but is neither very sensitive nor specific if used exclusively 2.

Case Discussion

This case is an example of myocardial tissue characterization in a patient with typical features of myocarditis.

According to the Lake Louise criteria, both main criteria are fulfilled 2:

In addition, there is mild systolic dysfunction present, which further supports the diagnosis and accounts as one of the supportive criteria (pericarditis, systolic dysfunction).

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