Ultra-low-dose chest CT versus chest X-ray for acute pulmonary disease Clinical and societal implications

Radiological imaging plays a pivotal role in clinical decision-making in the work-up of ED patients with non-traumatic pulmonary complaints. Ultra-low-dose chest CT (ULDCT) offers the possibility to obtain detailed imaging at a radiation dose similar to that of conventional chest X-ray (CXR). Optimal implementation of such a novel imaging technique with a higher diagnostic accuracy than the default modality requires evidence on the impact on patient management and efficiency. Therefore, this thesis studied the impact on patient outcome and societal outcome of replacing CXR by ULDCT in patients presenting at the ED with non-traumatic pulmonary complaints. We designed the OPTIMACT trial, a multicenter, pragmatic, non-inferiority randomized controlled trial comparing ULDCT to CXR in consecutive adult patients presenting at the ED with non-traumatic pulmonary complaints. We demonstrated that ULDCT was non-inferior in short-term functional health with minimal differences in hospital admissions, length of stay, mortality, and economic impact compared to CXR. There were more incidental findings, but less additional imaging procedures after 28 days with ULDCT. In patients with an atypical presentation of pneumonia ULDCT performed better than CXR.
ULDCT was more accurate in detecting pulmonary infections, but less accurate in detecting pulmonary congestion. Awareness for early radiological features of pulmonary congestion may improve the recognition of pulmonary congestion at ULDCT and CXR.
Overall, the results of our trial do not support the unconditional use of ULDCT in the work-up of patients presenting with non-traumatic pulmonary disease at the ED. It is recommended to consider the use of ULDCT instead of CXR in vulnerable patients.