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Cardiothoracic emergency imaging: evolution of the evaluation.

The perennial top four discharge diagnoses for emergency department (ED) visits in the United States and the developed world center on chest–related conditions. These include the familiar culprits of cardiac disease (both ischemic and non-ischemic), chest pain and pneumonia.1 Coupled with the continued incremental utilization of CT, with CT scanners often now located in the ED, it comes as no surprise that radiologists have seen a tremendous growth in the number of Chest CT examinations in the past 10–15 years.2,3 A plethora of technological innovations have brought beneficial adaptions in contrast, spatial and temporal resolution to our imaging of cardiothoracic emergencies, particularly for angiographic imaging. In turn, not only has the imaging of established clinical indications such as pulmonary embolism and acute aortic diseases improved, but the acute evaluation of coronary arterial disease has become a pragmatic proposition. A byproduct of the use of such multidetector CT systems is the current near ubiquitous availability of isotropic datasets and hence the ability to concomitantly offer multiplanar volumetric high-resolution CT (HRCT) lung parenchymal imaging. In essence, the on-call ED radiologist has been converted into a full service cardiothoracic radiologist interpreting studies with lung images rivalling those obtained in dedicated HRCT examinations. In trying to perform the task of providing a clinically directed, comprehensive cardiopulmonary evaluation, the cardiothoracic or ED radiologist faces a formidable challenge. Not only must he or she be abreast of our changing technical imaging capability, but the practitioner must also be aware of advances in our understanding of the basic pathophysiology of these common diseases. However, as radiologists imaging patients with acute cardiothoracic diseases, we are also aware of wider imaging utilization concerns. Even in the era of increased radiation awareness, only a modest decrease in CT use in the ED has been witnessed in recent years.4 As radiologists we must strive to best use radiation reduction mechanisms that do not impair our ability to accurately diagnose diseases that may have profound acute effects. Of course one of the best ways to reduce radiation exposure overall is not to perform radiological examinations that do not impact clinical outcome or to consider non-ionizing radiation alternatives. The counterpart of course is the need to perform additional examinations where these can alter clinical management pathways or to provide a level of detail that assists clinical stratification or patient management. In this special issue of the Journal of Thoracic Imaging, we have aimed to address these trends in cardiothoracic imaging, namely a comprehensive angiographic assessment of the vasculature and HRCT assessment of the lung parenchyma, an optimization not only of technique and interpretation, but also a realization that the ED radiologist is often at the forefront of emergent treatment planning requiring a current understanding of pathology, clinical pathways and relevance. Every article in this two-part symposium has been carefully constructed to address these issues. Dr Devaraj and colleagues5 have brought us up to date with the clinicoradiological stratification of pulmonary embolism and highlighted how CT pulmonary angiography use interacts with some of the most advanced clinical decision support rules (Geneva, PERC and Wells). Dr Raptis and colleagues highlight important imaging features of traumatic aortic injuries to guide assessment for interventional endovascular or surgical therapy including emerging clinical and radiological concepts with regards to minimal aortic injuries.6 In a companion article Dr Ridge and colleagues address our evolving understanding of the interconnected diagnoses of non-traumatic acute aortic syndromes and how these impact our interpretation and management planning.7 Completing the vascular theme Dr White and colleagues assess the status of imaging of coronary artery syndromes,