United Kingdom standards for non-invasive cardiac imaging: recommendations from the Imaging Council of the British Cardiovascular Society.

Heart and circulatory diseases affect more than seven million people in the UK. Non-invasive cardiac imaging is a critical element of contemporary cardiology practice. Progressive improvements in technology over the last 20 years have increased diagnostic accuracy in all modalities and led to the incorporation of non-invasive imaging into many standard cardiac clinical care pathways. Cardiac imaging tests are requested by a variety of healthcare practitioners and performed in a range of settings from the most advanced hospitals to local health centres. Imaging is used to detect the presence and consequences of cardiovascular disease, as well as to monitor the response to therapies. The previous UK national imaging strategy statement which brought together all of the non-invasive imaging modalities was published in 2010. The purpose of this document is to collate contemporary standards developed by the modality-specific professional organisations which make up the British Cardiovascular Society Imaging Council, bringing together common and essential recommendations. The development process has been inclusive and iterative. Imaging societies (representing both cardiology and radiology) reviewed and agreed on the initial structure. The final document therefore represents a position, which has been generated inclusively, presents rigorous standards, is applicable to clinical practice and deliverable. This document will be of value to a variety of healthcare professionals including imaging departments, the National Health Service or other organisations, regulatory bodies, commissioners and other purchasers of services, and service users, i.e., patients, and their relatives.

CT imaging prior to transcatheter aortic valve implantation in the UK.

Objective: This cross-sectional observational study sought to describe variations in CT in the context of transcatheter aortic valve implantation (CT-TAVI) as currently performed in the UK. Methods: 408 members of the British Society of Cardiovascular Imaging were invited to complete a 27-item online CT-TAVI survey. Results: 47 responses (12% response rate) were received from 40 cardiac centres, 23 (58%) of which performed TAVI on-site (TAVI centres). Only six respondents (13%) performed high-volume activity (>200 scans per year) compared with 13 (28%) performing moderate (100-200 scans per year) and 27 (59%) performing low (0-99 scans per year) volume activity. Acquisition protocols varied (41% retrospective, 12% prospective with wide padding, 47% prospective with narrow padding), as did the phase of reporting (45% systolic, 37% diastolic, 11% both, 6% unreported). Median dose length product was 675 mGy.cm (IQR 477-954 mGy.cm). Compared with non-TAVI centres, TAVI centres were more likely to report minimum iliofemoral luminal diameter (n=25, 96% vs n=7, 58%, p=0.003) and optimal tube angulation for intervention (n=12, 46% vs n=1, 8%, p=0.02). Conclusions: This national survey formally describes current CT-TAVI practice in the UK. High-volume activity was only present at one in seven cardiac CT centres. There is wide variation in scan acquisition, scan reporting and radiation dose exposure in cardiac CT centres.

Complementary role of cardiac CT in the assessment of aortic valve replacement dysfunction.

Aortic valve replacement is the second most common cardiothoracic procedure in the UK. With an ageing population, there are an increasing number of patients with prosthetic valves that require follow-up. Imaging of prosthetic valves is challenging with conventional echocardiographic techniques making early detection of valve dysfunction or complications difficult. CT has recently emerged as a complementary approach offering excellent spatial resolution and the ability to identify a range of aortic valve replacement complications including structural valve dysfunction, thrombus development, pannus formation and prosthetic valve infective endocarditis. This review discusses each and how CT might be incorporated into a multimodal cardiovascular imaging pathway for the assessment of aortic valve replacements and in guiding clinical management.

Multimodality imaging in heart valve disease.

In patients with heart valve disease, echocardiography is the mainstay for diagnosis, assessment and serial surveillance. However, other modalities, notably cardiac MRI and CT, are used if echocardiographic imaging is suboptimal but can also give complementary information to improve assessment of the valve lesion and cardiac compensation to aid the timing of surgery and determine risk. This statement discusses the way these imaging techniques are currently integrated to improve care beyond what is possible with echocardiography alone.

Dilatation of the aorta in pure, severe, bicuspid aortic valve stenosis.

BACKGROUND: Aortic complications are more frequent after bicuspid aortic valve (BAV) replacement (AVR), than tricuspid aortic valve replacement. We studied the size of the proximal thoracic aorta in patients with BAV undergoing AVR for pure, severe aortic stenosis, looking for dilatation in comparison with patients with a matched tricuspid aortic valve (TAV) and normograms of aortic size. METHODS: Aortic root and ascending aortic diameter measurements were taken at 3 levels, from electrocardiographic-gated multidetector row computed tomograms, in 28 patients with pure, severe aortic stenosis before AVR. The patients were divided in 2 groups (BAV, n = 10; TAV, n = 18). Patients with greater than mild aortic regurgitation or who were scheduled for aortic root replacement were excluded. RESULTS: Although patients in the BAV group were younger (P <.0001) and less likely to have hypertension (P <.005), their aortic diameters were larger than those of patients in the TAV group at all levels measured (aortic sinus, 41.1 +/- 8.1 mm vs 33.8 +/- 3.3 mm; sino-tubular junction, 39.0 +/- 7.8 mm vs 31.1 +/- 3.8 mm; right pulmonary artery level, 42.8 +/- 7.1 mm vs 33.7 +/- 4.3 mm; P <.005 for all). Whereas 60% (6/10) of patients in the BAV group had >/=1 aortic diameter measurements greater than the 95th age-adjusted percentile, 0% (0/18) of patients in the TAV group did. CONCLUSIONS: Patients with BAV undergoing AVR with pure, severe aortic stenosis commonly have moderate dilatation of the thoracic aorta, whereas matched patients with a TAV do not. This finding may contribute to the increased frequency of aortic complications seen in follow up of patients with a BAV after AVR.

Morphologic assessment of patent ductus arteriosus in adults using retrospectively ECG-gated multidetector CT.

OBJECTIVE: Noninvasive imaging of a persistently patent ductus arteriosus in adults remains a challenge. Bearing in mind the excellent spatial resolution provided by multidetector CT (MDCT), we postulated that MDCT might be used to evaluate this anatomic defect. We sought to show that MDCT can depict in detail patent ductus arteriosus in adults and allow determination of the size of the duct, degree of calcification, and morphologic classification. CONCLUSION: MDCT represents a novel method of noninvasively assessing patent ductus arteriosus in adults that provides detailed anatomic information. Comparison with invasive angiographic findings is needed to validate the technique of sizing of ducts using MDCT.

Calcified patent ductus arteriosus diagnosed following aortic valve replacement.

A 71-year-old woman underwent aortic valve replacement for severe, symptomatic aortic stenosis. The left ventricle filled rapidly when the left ventricular vent was switched off and postoperatively she was slow to recover with bilateral pleural effusions. These findings prompted early reinvestigation, initially with echocardiography and subsequently with multi-detector row computed tomography. Using a retrospectively electrocardiographic-gated acquisition, adapted from a noninvasive coronary angiography protocol, a calcified, persistently patent ductus arteriosus was identified as the cause for her perioperative and postoperative condition. The defect has since been closed successfully using a transcatheter technique.

Thoracic aorta at multi-detector row CT: motion artifact with various reconstruction windows.

The authors assessed motion artifact of the thoracic aorta in 25 patients who underwent multi-detector row computed tomography (CT) with retrospective electrocardiographic (ECG) gating. CT reconstructions centered at four phases of diastole were compared for five different levels of the thoracic aorta. A significant positive correlation was observed between heart rate and motion artifact (r = 0.72, P <.001). The optimal reconstruction phase varied between patients, and this was directly related to heart rate. For patients with a heart rate of 70 beats per minute, the reconstruction phase centered at 75% of the R-R interval had the significantly least motion artifact (P =.004). Conversely, the optimal reconstruction phase for patients with heart rates above 70 beats per minute was centered at 50% of the R-R interval (P =.09).