Coronary CT with late iodine enhancement found a cause in most patients with troponin rise and no infarct

Design

Prospective single-centre cohort

Population

191 emergency patients with raised troponin and no acute MI criteria

Primary outcome

Change in working diagnosis after CT

Effect

Diagnosis changed in 48%; agreement with discharge diagnosis 0.94 (95% CI 0.89 to 0.97)

This prospective single-centre study enrolled 191 consecutive emergency patients (median age 70) with acute chest pain or equivalent symptoms, raised troponin and no diagnosis of acute myocardial infarction, between 2018 and 2025. All had coronary CT angiography; those without obstructive disease went on to late iodine enhancement imaging and, if negative, extracellular volume mapping in the same visit.

Obstructive coronary disease was found in 40%. Of the 106 without it, tissue imaging was positive in 55%, showing myocarditis (30%), infarction with non-obstructive arteries (8%), Takotsubo (13%), amyloidosis (3%) and dilated cardiomyopathy (1%). The protocol changed the working diagnosis in 48% of patients and agreed with the final discharge diagnosis in 94%. No major cardiac events occurred over a median of 24 months in patients with a fully negative scan.

Raised troponin without an infarct is common with high-sensitivity assays, and these patients often wait for separate angiography and cardiac MRI. A single CT visit that answers both the coronary and the myocardial question could shorten that path, particularly where MRI access is limited, as in many Indian hospitals. This is one centre without a comparison group, and late iodine enhancement needs scanner capability and reader experience, so it is a protocol to consider building rather than a proven replacement for MRI.

• Consider adding late iodine enhancement to coronary CT angiography for troponin-positive patients without infarction where scanner and expertise allow.
• Report myocardial findings in categories that map to clinical diagnoses: myocarditis, MINOCA, Takotsubo, infiltrative disease.
• Agree a joint protocol with cardiology covering who is scanned and when.
• Recognise that cardiac MRI remains the reference standard for tissue characterisation.
• Audit agreement between CT and final diagnosis if the protocol is introduced locally.

Why it matters

It could give one-visit answers to a common emergency dilemma that usually needs two separate tests.

Don't overread it

A single-centre study without a comparison arm cannot show this protocol improves outcomes or matches cardiac MRI.

The statistics, in plain English

Agreement of 0.94 with discharge diagnosis is high, but the discharge diagnosis was made with knowledge of the CT, which inflates agreement. Zero events in scan-negative patients is reassuring but comes from a small group, so the true event rate could still be a few percent.

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