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Cardiovascular CT: the role of cardiologists
  1. Muhummad Sohaib Nazir1,
  2. Edward D Nicol2
  1. 1 Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
  2. 2 Departments of Cardiology and Radiology, Royal Brompton and Harefield NHS Foundation Trust, London, UK
  1. Correspondence to Dr. Edward D Nicol, Departments of Cardiology and Radiology, Royal Brompton and Harefield NHS Foundation Trust, London SW3 6NP, UK; e.nicol{at}nhs.net, cyprusdoc{at}doctors.org.uk

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Role of cardiac CT

CT is an increasingly pivotal diagnostic tool for cardiovascular disease and preprocedural planning for structural intervention and device implantation. CT coronary angiography (CTCA) has gained prominence in UK clinical practice as it is now recommended in the National Institute for Health and Care Excellence guidelines as the first-line test for the investigation of anginal symptoms in those without known coronary artery disease (CAD).1 CTCA is an excellent rule-out test for CAD (figure 1) but has an increasingly robust positive predictive value, especially when combined with CT-fractional flow reserve,2 which is currently being funded as part of an NHS England Innovation programme. Recent evidence has demonstrated the addition of CTCA to standard of care in patients from rapid access chest pain clinics reduced non-fatal myocardial infarction rates by over 40%.3

Figure 1

Typical CT coronary angiogram images of a patient referred for investigation of coronary artery disease. (A) 3D volume rendered images demonstrated the anatomical distribution of the left anterior descending (LAD) and diagonal vessels. (B) Centre-vessel tracking reconstructed images of the LAD demonstrated no significant coronary stenosis or atheroma.

In structural heart disease, such as prior to transcatheter aortic valve implantation, CT can provide accurate dimensions of the aortic annulus, root and coronary ostia to guide valve sizing and intravenous access route (figure 2).4 Prior to mitral valve intervention, detail on mitral valve annulus morphology, calcification, landing zone and anatomical relation to the left circumflex artery can be acquired to guide device sizing and implantation.5 Furthermore, CT is important in the workup for electrophysiology procedures to evaluate the size, position and morphology of the atria, pulmonary veins and left atrial appendage prior to radiofrequency ablation and left atrial exclusion.6 It is increasingly used in the assessment of both paediatric and adult congenital heart disease, especially when cardiac MRI is contraindicated.

Figure 2

Preprocedural reconstructed images demonstrating accurate dimensions and morphology to guide transcatheter aortic valve implantation (TAVI). (A) Aortic annulus, (B) aortic root, (C) distance from aortic annulus to ostia of coronary arteries, (D, E) orthogonal views of the iliofemoral arteries for access routes, (F) 3D volume rendered reconstruction of the entire arterial tree from aortic root to femoral arteries.

Technology and image processing has rapidly progressed such that radiation doses have markedly reduced by 78% over 10 years,7 and with emerging cost-effectiveness evidence, CT has an expanding role for diagnosis of cardiovascular disease.

Role of cardiologists

Increasingly, all cardiologists require a clear understanding of indications and limitations (table 1), contraindications, radiation burden and strengths of cardiovascular CT. Referring clinicians need to provide sufficient clinical details and indicate clear clinical questions. This allows adequate planning of image acquisition to obtain optimal images with least radiation and in turn enables reporters to produce high-quality relevant reports to guide patient care. While the indications and evidence base are expanding for cardiovascular CT, there is a clear shortfall in trained clinicians to meet UK service requirements.8 Thus, there is a need to train the next generation of cardiovascular imagers to meet this challenge nationally and internationally.

Table 1

Indications and limitations for cardiovascular CT

Accreditation

Formal accreditation requires demonstration of skills and knowledge through experience and participation in image acquisition, reporting and formal lectures.9 Currently, level I accreditation provides familiarity to cardiovascular CT and requires 50 CTCA reports, while level II accreditation requires accurate interpretation of cardiovascular CT and is achieved by reporting a case mix of 150 studies. Given the increasing role of cardiovascular CT in routine clinical practice there may be a case to incorporate level II training as a core requirement for cardiologists in both Europe and the UK. Level III accreditation is reserved for clinicians with considerable expertise in performing and reporting CT and capable to lead a clinical/academic unit or provide high-quality education in the field.

In summary, cardiovascular CT is an increasingly central non-invasive imaging test in cardiology with growing diagnostic and clinical application that will likely hold an increasingly important role in future cardiovascular care.

References

Footnotes

  • Contributors EDN conceived the idea of this article. MSN and EDN jointly wrote this manuscript.

  • Funding This study was funded by the Medical Research Council (grant number MR/P01979X/1).

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

  • Patient consent for publication Not required.