Novel imaging approaches in adult asthma and their clinical potential

Abstract

Currently, imaging in asthma is confined to chest radiography and CT. The emergence of new imaging techniques and tremendous improvement of existing imaging methods, primarily due to technological advancement, has completely changed its research and clinical prospects. In research, imaging in asthma is now being employed to provide quantitative assessment of morphology, function and pathogenic processes at the molecular level. The unique ability of imaging for non-invasive, repeated, quantitative, and in vivo assessment of structure and function in asthma could lead to identification of ‘imaging biomarkers’ with potential as outcome measures in future clinical trials. Emerging imaging techniques and their utility in the research and clinical setting is discussed in this review.

Keywords:

• asthma
• endobronchial ultrasound
• hyperpolarized MRI
• molecular imaging
• optical coherence tomography
• positron emission tomography
• quantitative computed tomography

Financial & competing interests disclosure

S Gupta is a National Institute for Health Research (NIHR) Clinical Lecturer and is funded by a research and career development training scheme. C Brightling is a NIHR senior fellow and has received grant and consultancy funding via his institution from GSK, MedImmune/AstraZeneca, Roche/Genentech, Novartis, Chiesi and Boehringer-Ingelheim. This paper presents independent research funded by the National Institute for Health Research (NIHR). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Imaging in asthma is at a new horizon with emergence of exciting new modalities and continued improvement of existing techniques.

• Computed tomography has evolved from being a tool for qualitative structural assessment to a technique for accurate, repeatable, quantitative structural and functional assessment of asthma.

• MRI allows novel assessments in asthma including pulmonary ventilation, perfusion and assessment of small airways.

• Endobronchial ultrasound and optical coherence tomography can probe the microstructure of the airways in vivo, due to their high resolution.

• Molecular imaging in asthma is providing insight into the pathogenic pathways at molecular and cellular levels.

• Imaging is being used in asthma phenotyping with potential to identify new disease subtypes.

• Computational modeling is multi-modality, multi-scale approach to study asthma with an aim to gain new insights into disease pathophysiology, unravel structure–function relationship and make predictive and personalized medicine a reality.

• Imaging biomarkers have an immense potential as outcome measures in future clinical trials.

• Some of the imaging techniques described involve exposure to ionizing radiation and a risk–benefit assessment before imaging is pertinent.