Cardiac MRI — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 23-year-old man presents 3 days after a flu-like illness with acute infarct-like chest pain, ST-segment changes and myocardial injury with a raised troponin, and is admitted. Invasive coronary angiography shows no coronary stenosis of 50% or more, and the final diagnosis is not clear after angiography, so MINOCA is the working diagnosis. Myocarditis is suspected. He has no cardiac device and normal renal function.^[14][2][13]

1. Give the three ESC rows that support CMR now, each with its class and level: the two ESC 2025 myocarditis and pericarditis rows (Recommendation Tables 1 and 3) and the ESC 2023 ACS row for a working diagnosis of MINOCA. (3)^[2][14]
2. State how ESC 2025 says the updated Lake Louise criteria diagnose non-ischaemic myocardial inflammation, and the three CMR categories. (3)^[2]
3. What does ESC 2025 say about the timing of CMR in myocarditis, and when does ESC 2023 ACS say CMR should be performed in a working diagnosis of MINOCA? Which LGE patterns does ESC 2025 describe for myocyte necrosis and fibrosis? (2)^[2][14]
4. If CMR confirms myocarditis, give the two ESC 2025 follow-up rows that include CMR, each with its class and level. (2)^[2]

Model answers — SAQ 1

1. ESC 2025 Recommendation Table 1: CMR is recommended in patients with the clinical suspicion of myocarditis (using updated Lake Louise criteria) and/or pericarditis for the non-invasive diagnosis of inflammatory reaction (Class I, Level B) (1 mark).^[2] ESC 2025 Recommendation Table 3: CMR is recommended in patients with suspected myocarditis to reach a clinical diagnosis and to determine the cause of acute myocardial injury, including assessment of oedema, ischaemia, and necrosis/fibrosis/scarring (Class I, Level B) (1 mark).^[2] ESC 2023 ACS Recommendation Table 13: in patients with a working diagnosis of MINOCA, CMR imaging is recommended after invasive angiography if the final diagnosis is not clear (Class I, Level B) (1 mark).^[14] Not marked, but also applicable: the AHA/ACC 2021 chest pain guideline's table for acute chest pain with suspected myopericarditis includes two CMR rows. In patients with acute chest pain and myocardial injury who have nonobstructive coronary arteries on anatomic testing, CMR with gadolinium contrast is effective to distinguish myopericarditis from other causes, including myocardial infarction and nonobstructive coronary arteries (MINOCA) (COR 1, LOE B-NR).^[13] If acute myopericarditis is suspected, the same table's other CMR row also applies: in patients with acute chest pain with suspected acute myopericarditis, CMR is useful if there is diagnostic uncertainty, or to determine the presence and extent of myocardial and pericardial inflammation and fibrosis (COR 1, LOE B-NR); this row is also not marked.^[13]
2. Diagnosis rests on at least one T2-based criterion plus ideally one T1-based criterion; both together increase specificity for diagnosing acute myocarditis, while one criterion can still support possible myocarditis in an appropriate clinical scenario, with less specificity (1 mark).^[2] Proven = 2 out of 2 updated LLC fulfilled; uncertain = only 1 out of 2 fulfilled (1 mark).^[2] Rejected = negative CMR (1 mark).^[2]
3. ESC 2025: the diagnostic accuracy of CMR is higher if performed early, best within the first 2 weeks; ESC 2023 ACS: in a working diagnosis of MINOCA, CMR should be performed as soon as possible after presentation to maximise diagnostic yield, ideally during the index admission (1 mark).^[2][14] Non-ischaemic (e.g. mid-wall, subepicardial, patchy) LGE patterns that do not typically follow a coronary artery distribution (1 mark).^[2]
4. ESC 2025 Recommendation Table 3: CMR is recommended for follow-up at least within the first 6 months in patients with myocarditis to identify a healed or ongoing process, for risk stratification and personalised therapy, and to enable a return to exercise (Class I, Level C) (1 mark).^[2] ESC 2025 Recommendation Table 15: follow-up with clinical assessment, biomarkers (at least troponin), ECG, exercise test, Holter-ECG monitoring, echocardiography, and CMR at least within 6 months after the index hospitalisation is recommended in all patients with myocarditis to identify a potential progression or new risk factors (Class I, Level C) (1 mark).^[2]

SAQ 2 (10 marks)

Practice scenario. A 44-year-old man has hypertrophic cardiomyopathy, diagnosed on echocardiography 5 years ago, and attends follow-up. His estimated 5-year SCD risk is in the ESC low-risk category (<4%). After clinical assessment that includes personal and family history, echocardiography and ambulatory ECG monitoring, he is not otherwise identified as high risk for SCD (no major SCD risk factors under the AHA/ACC 2024 guideline), and the decision to proceed with an ICD remains uncertain. He has never had CMR.^[1][7]

1. Give the AHA/ACC 2024 row from its recommendations for CMR imaging that supports CMR now, with its COR and LOE, and the four things it assesses. (2)^[7]
2. How does AHA/ACC 2024 Table 8 define extensive LGE? (2)^[7]
3. His CMR shows LGE of 18% of LV mass and no finding that is a major SCD risk factor under the AHA/ACC 2024 guideline. Give the ESC 2023 row and the AHA/ACC 2024 row on using the LGE in the ICD decision, each with its class or COR. (4)^[1][7]
4. Give one ESC 2023 statement and one AHA/ACC 2024 statement on how LGE is quantified. (2)^[1][7]

Model answers — SAQ 2

1. For patients with HCM who are not otherwise identified as high risk for SCD, or in whom a decision to proceed with ICD remains uncertain after clinical assessment that includes personal or family history, echocardiography, and ambulatory electrocardiographic monitoring, CMR imaging is beneficial (COR 1, LOE B-NR) (1 mark).^[7] It assesses maximum LV wall thickness, EF, LV apical aneurysm, and extent of myocardial replacement fibrosis with LGE (1 mark).^[7] Not marked, but also applicable: AHA/ACC 2024 recommendations for SCD risk assessment in adults with HCM: for adult patients with HCM who are not otherwise identified as high risk for SCD, or in whom a decision to proceed with ICD placement remains uncertain after clinical assessment that includes personal/family history, echocardiography, and ambulatory electrocardiographic monitoring, CMR imaging is beneficial to assess for maximum LV wall thickness, EF, LV apical aneurysm, and extent of myocardial fibrosis with LGE (Table 8) (COR 1, LOE B-NR).^[7] Not marked, but also applicable: ESC 2023 Recommendation Table 5: contrast-enhanced CMR should be considered in patients with cardiomyopathy during follow-up to monitor disease progression and aid risk stratification and management (Class IIa, Level C).^[1]
2. Extensive LGE represents replacement fibrosis, either quantified or estimated by visual inspection, comprising ≥15% of LV mass (1 mark).^[7] The extent of LGE conferring risk has not been defined in children (1 mark).^[7]
3. ESC 2023: for patients in the low-risk category (<4% estimated 5-year risk of SCD), extensive LGE (≥15%) on CMR may be considered in shared decision-making about prophylactic ICD implantation, acknowledging the lack of robust data on the impact of scar quantification on personalised risk estimates generated by HCM Risk-SCD or a validated paediatric model (1 mark).^[1] Class IIb, Level B (1 mark).^[1] AHA/ACC 2024: in select adult patients with HCM and without major SCD risk factors after clinical assessment, or in whom the decision to proceed with ICD placement remains otherwise uncertain, an ICD may be considered in patients with extensive LGE by contrast-enhanced CMR imaging or NSVT on ambulatory monitoring (1 mark).^[7] COR 2b, LOE B-NR (1 mark).^[7]
4. ESC 2023: LGE varies substantially with the quantification method used, and the 2-standard deviation technique is the only one validated against necropsy (1 mark).^[1] AHA/ACC 2024: no consensus on the optimal quantification technique(s) has been determined (1 mark).^[7]