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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Cardiac MRI and nuclear imaging

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull

Synopsis

Select CMR, SPECT or PET for ventricular function, tissue characterisation, perfusion, viability and infiltrative disease while managing contrast, device and radiation constraints.

  • CMR provides accurate biventricular volumes, function and tissue characterisation without ionising radiation.
  • Late gadolinium enhancement pattern helps distinguish ischaemic scar from many non-ischaemic cardiomyopathies but is not a diagnosis in isolation.
  • Stress CMR, SPECT and PET can demonstrate inducible perfusion abnormality; PET can quantify myocardial blood flow in specialist practice.
  • SPECT compares relative tracer uptake, so attenuation artefact and balanced multivessel ischaemia can conceal disease.
  • Check the exact implanted device and leads for MR conditions; 'pacemaker' is not automatically an absolute contraindication.
  • Use the lowest-risk suitable gadolinium agent and screen renal function and pregnancy according to the product and MHRA safety guidance.
  • Justify ionising-radiation studies, optimise dose and avoid duplicate functional tests that will not change management.

Key red flags

Extensive ischaemia or severe dysfunction

Large inducible burden, marked biventricular dysfunction or a mechanical complication requires prompt specialist action.

Tracer or contrast reaction

New airway, breathing or circulatory compromise during injection requires immediate emergency management and documentation.

Investigation priorities

01
Cine CMRFirst step

Quantify chamber volumes, mass and biventricular ejection fraction.

Management branches

Preferred routeSuspected cardiomyopathy or myocarditis

Unexplained ventricular dysfunction, arrhythmia or myocardial injury

  1. Obtain ECG, biomarkers and comprehensive echocardiography and address acute instability.
  2. Use CMR when tissue characterisation or accurate biventricular assessment will change diagnosis or management.
  3. Review device compatibility, renal function, pregnancy possibility and tolerance before scanning.
  4. Escalate high-risk arrhythmia, severe dysfunction or active inflammation findings through specialist pathways.
Open full textbook →Answer 2 questionsCardiology check
Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE CG95: Recent-onset chest pain
  • NICE NG106: Chronic heart failure in adults
  • MHRA: Gadolinium contrast restrictions and safety
  • ESC/EACVI cardiovascular imaging consensus documents
  • ESC 2024 Guidelines for chronic coronary syndromes

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom