Cardiac magnetic resonance (CMR) can help identify patients with pericarditis who would otherwise fall through diagnostic cracks – while also ruling it out in nearly half of those initially labelled with the condition, new data show.
Published in Heart [link here], the study offers strong real-world support for the 2025 European Society of Cardiology (ESC) guideline update, which formally recognises CMR as a diagnostic criterion for pericarditis. The findings also point to a more nuanced, individualised diagnostic approach – particularly in patients with persistent or ambiguous symptoms, say a team of investigators from Australia, Canada and Switzerland, including lead investigator, cardiologist Dr Christopher Naoum from Concord Hospital in Sydney.
Among 2530 patients referred for CMR at a US tertiary centre, 88 were evaluated specifically for suspected pericarditis or myopericarditis. Of those, 43 (49%) had scan-confirmed pericardial inflammation, while 45 (51%) did not. Notably, almost one-third (13/43, 30%) of those with positive CMR findings did not meet the 2015 ESC clinical criteria for diagnosis – highlighting the risk of underdiagnosis in patients with atypical or subacute disease, say the researchers. Conversely, nearly half (24/45, 47%) of those with negative scans had met the clinical criteria.
Importantly, those with CMR-confirmed pericarditis who lacked clinical signs had similar disease severity on imaging to those who did meet diagnostic criteria. This subgroup also had significantly lower rates of chest pain and ECG changes – possibly reflecting less myocardial involvement and a greater prevalence of non-idiopathic or subacute presentations, investigators said.
“Our data demonstrate that in those patients without sufficient clinical evidence, CMR can have a huge impact on securing the diagnosis,” the authors wrote. Suspicion may be raised in the context of an atypical, subacute presentation, pericardial effusion or unexplained elevated CRP”.
They also suggested that these patients may represent a non-inflammatory phenotype, which has been previously described, although the pathogenesis and relevant biomarkers of this condition remain under investigation.
Pericardial effusion and elevated C-reactive protein (CRP) emerged as the strongest predictors of pericardial inflammation on imaging. Patients with moderate-to-severe late gadolinium enhancement (LGE) had a median CRP of 178 mg/L (IQR 98–253) and effusions in 88% of cases – compared to a CRP of 35 mg/L (IQR 7–63) and effusions in just 19% of those with minimal or mild enhancement (p < 0.05 for both). A CRP level above 50 mg/L had a moderate predictive value for CMR-positivity, with 56% sensitivity and 84% specificity.
“These markers can help clinicians triage which patients may benefit from CMR, particularly when symptoms are unclear or persistent,” the authors said.
CMR also proved valuable in excluding pericarditis where clinical signs were present but no inflammation was found on imaging. Among these patients, the most common alternate diagnoses were myocarditis or a normal scan – allowing for more confident de-escalation or discontinuation of anti-inflammatory therapy, the team proposed.
“CMR differentiated pericarditis from myocarditis on the overlapping spectrum of inflammatory myopericardial syndromes, and also from other causes of chest pain or cardiomyopathies,” the researchers noted – with alternative findings present in 18% of CMR-negative cases.
While the retrospective, single-centre study has limitations – including potential referral bias and non-standardised assessment of clinical signs – the authors argue their findings support a more prominent role for CMR in routine diagnostic pathways.
“These real-world data provide further evidence in support of the new 2025 ESC guidelines,” they concluded.