Thoracic Imaging

The current issue of Seminars in Respiratory and Critical Care Medicine is entirely devoted to chest imaging and its recent technological developments. Because chest radiologists are at the cross-road between physicists, developers of highly sophisticated machines, and clinicians, who refer their patients for specific clinical situations, the latter have to be regularly informed of the new trends in imaging. With this objective in mind, internationally renowned authors have accepted to share their expertise on specific fields of chest imaging to allow clinicians to become more familiar with several new options, mature enough to be introduced into clinical practice. As chest radiography remains the key primary tool for screening and monitoring pulmonary disease, the first series of manuscripts in this issue are devoted to this modality which has shown a dramatic improvement in detection efficiency. In many instances, it represents the initial macroscopic approach of the underlying disease, influencing more sophisticated approaches using cross-sectional imaging. Between chest radiography and computed tomography (CT), digital tomosynthesis tries to find a “path of reason,” hampered by the ongoing technological revolutions of CT. Although the respective roles of CT and digital tomosynthesis remain yet to be defined, it is important to inform readers of the efforts developed in the field of first-line chest imaging modalities. When considering CT, magnetic resonance imaging (MRI), and positron emission tomography (PET)-CT, the current trend is obviously toward “integration,” a concept that has already entered radiological practice and that can be described in several different realms. Owing to dramatic developments in CT technology, chest imaging now encompasses imaging of the heart on routine chest examinations. This integration gives the opportunity to screen asymptomatic disorders, in particular cardiovascular comorbidities in the routine assessment of respiratory diseases that can be simultaneously assessed from the same examination. Chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis are two targets for such combined approaches that have raised great interest among chest physicians in the recent years. The second level of integration is the combined assessment of morphology and function in respiratory as well as cardiovascular diseases. The choice of CT versus MRI as the most suitable approach remains debatable, as both modalities are able to provide morphological and functional information on lung ventilation and perfusion as well as cardiac function. While the two technologies can often compete against each other, this situation can trigger their respective technological developments with a similar goal, namely, the possibility of modifying diagnostic strategies with substitutions between investigations. This ultimate goal is certainly the most ambitious to consider for the medical community, at a patient level and also regarding the economic challenges we face. A realistic analysis imposes on us to acknowledge that it will take time to approach substitutions, but this objective can be reasonably achievable by a constant collaboration between radiologists and clinicians. It is also increasingly common to find an integrated approach between plain radiographic imaging, CT, MRI, ultrasound, and nuclear medicine. The integration between PET and CT as well as between PET and MRI will soon become the precursor of all mergers needed between molecular, morphological, and functional imaging. We hope that the readers of this issue of Seminars in Respiratory and Critical Care Medicine will find answers to their questions regarding the new directions they could follow in their daily practice. We would also like to express our sincere thanks to each of the authors who contributed to this issue, as they have been generous enough to share their extraordinary experience setting aside their busy schedules. As clinical and radiological practices evolve into ever-increasing sophistication, this issue aims to provide a modest contribution toward a clearer understanding of our respective evolutionary steps that in turn would serve for the greatest benefit of our patients.