Introduction Cardiac magnetic resonance (CMR) is an increasingly important imaging modality, which by necessity incorporates a large field of view. Both “localiser” and multiple slice half-fourier spin echo (eg, HASTE) sequences provide coverage of the thorax and upper abdomen. Such imaging may reveal hitherto unexpected incidental extra-cardiac findings (IEF). First we sought to assess the frequency of IEF found on clinically indicated CMR scans. Second we compared the 3 clinically used HASTE acquisition protocols in this context. Lastly we determined the impact of the 3 different protocols on acquisition time and image quality.
Methods Three subsequent groups of 238 patients (714 patients in total), all referred for clinically indicated CMR, were scanned with either breath-hold (BH) HASTE (Group 1), free breathing (FB) HASTE (Group 2) or diaphragmatic navigated (NAV) HASTE (Group 3). Additionally “localiser” sequences performed in 3 orthogonal planes were analysed. All 714 clinical reports were reviewed regarding the presence of IEF. These were categorised as either minor, or major if recommendations for further investigation, follow-up, and/or clinical correlation were made. Finally, to determine the impact of each HASTE protocol on acquisition time and image quality, an additional cohort of 15 patients underwent 3 protocols back to back in a random fashion. The length of each acquisition was timed and image quality was reviewed and scored externally.
Results A total of 180 IEF were found in 162 (22.7%) out of 714 patients. There was no significant difference in frequency of IEF between the 3 HASTE groups. Out of 180 IEF, 88 were considered minor and 92 major findings. Of the latter, 8 (1.1%) were considered highly significant. These included one bronchoalveolar carcinoma stage 1B requiring lobectomy, 2 cases of florid sarcoidosis in patients presenting with VT and “structurally normal hearts” on echocardiography, one case of pulmonary aspergillosis, 2 cases of advanced pulmonary fibrosis, one ascending thoracic aortic aneurysm and a case of iatrogenic liver haemorrhage following placement of a pericardial drain. FB HASTE acquisition (69±2.5 s) was significantly faster than BH (105±3.8 s) and NAV (121±2.7 s), p<0.001, but also produced the lowest image quality on a 5 point scale; 3.5 (FB) vs 3.9 (BH) vs 3.8 (NAV), p=0.08.
Conclusion Overall, IEF are common and lead to follow on investigations in a substantial minority of cases. However, the overall incidence of highly significant findings in the current study was low (∼1%). There was no difference in the frequency of incidental extra-cardiac findings between the 3 HASTE protocols. While the free breathing HASTE technique is statistically significantly faster than breath hold and navigated HASTE, the absolute time saving is small and probably out-weighted by lesser image quality.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.