Cardiac iron overload protocol (MRI)
Citation, DOI & article data
Note: This article aims to frame a general concept of a cardiac MRI protocol in the above setting.
Protocol specifics will vary depending on additional clinical questions, differential diagnosis, MRI scanner type, specific hardware and software, radiologist and perhaps referrer preference, patient factors e.g. arrhythmia or breathing problems or implants, specific indications and time constraints.
1.5 vs 3 tesla
The mainstay for the assessment of iron overload is T2* mapping this should currently be performed at 1.5 tesla 3.
Checking indications, contraindications, explanation of the examination and obtaining informed consent is obvious as in other examinations.
Beyond that patient preparation for cardiac MRI includes the following:
- instruction how to breathe
- an electrocardiogram signal need to be acquired
A cardiac MRI is conducted in the supine position.
Multiphased array coils are recommended.
- anterior surface coil, posterior coil
- cardiac coil
- in-plane spatial resolution: will vary with the sequence
- field of view (FOV): will vary, for most planes a FOV ≤320 mm is recommended
- slice thickness: varies with the sequence and is usually 6-10 mm
The cardiac imaging planes differ from the normal axial, coronal and sagittal body planes 1-4:
- angulation: strictly axial
- volume: from the thoracic inlet to the diaphragm
horizontal long axis view or 4-chamber view (4ch)
- angulation: along the left ventricular long axis through the apex and the centers of the mitral and tricuspid valves
left ventricular vertical long axis view or 2-chamber view (2ch)
- angulation: along the left ventricular long axis through the left ventricular apex and the center of the mitral valve
sagittal left ventricular outflow tract (LVOT) or 3-chamber view (3ch)
- angulation: through the left ventricular apex, the center of the mitral valve and the left ventricular outflow tract and aortic valve
short-axis view (sax)
- angulation: perpendicular to the left ventricular long axis
T2 black-blood or SSFP
- purpose: overview, depiction of the cardiac surroundings and greats vessels, assessment of mediastinal lymphadenopathy in suspected sarcoidosis
- technique: T1 black-blood, T2 black-blood, SSFP ideally over 1-2 breath-holds
- planes: axial
- cine imaging
- T2* mapping
- T1 mapping (native)
- late gadolinium enhancement (C+)
The following considerations can be made in certain conditions:
- single shot modules or free breathing with real-time image acquisition in patients with difficulties holding their breath
- abdominal bands in profound respiratory motion
- peripheral pulse gating in patients with a weak ECG signal
- postponing the exam in patients with severe pleural effusion and related ghosting artefacts and breathing problems until after pleural drainage
- cine imaging
- cardiac volumes should be obtained as in every cardiac MRI
late gadolinium enhancement
- should be performed in case of decreased ejection fraction
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- 4. Torlasco C, Cassinerio E, Roghi A et al. Role of T1 Mapping as a Complementary Tool to T2* for Non-Invasive Cardiac Iron Overload Assessment. PLoS One. 2018;13(2):e0192890. doi:10.1371/journal.pone.0192890 - Pubmed