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.

Using imaging as a biomarker for asthma

“…Although chest radiography and computed tomography (CT) remain the primary imaging methods used in the clinical and research evaluation of asthmatic patients, there have been parallel advancements in a growing range of imaging techniques that are now available in both research and clinical arena ( Table 1 ) [1]. Modalities such as magnetic resonance imaging (MRI), endobronchial ultrasound (EBUS), optical coherence tomography (OCT) and positron emission tomography (PET) are among the techniques that can be used in pulmonary imaging of asthma patients to assess both structure and function, so that these parameters can be related back to more traditional clinical parameters for a broadened, personalized understanding of the individual patient [2].…”

Pulmonary quantitative CT imaging in focal and diffuse disease: current research and clinical applications

“…131 Asthma severity: proximal and distal airway The airway remodelling seen in asthmatic patients is a morphological feature that yields substantial promise of imaging biomarkers for personalized asthma care. 132,133 Airway remodelling is particularly targeted on QCT, notably, there is association between epithelial thickness and central airway quantification by CT. 94 This association led to definition of CT-based clinical clusters of asthma, with different clinical and therapeutic features. The imaging-based clustering of asthmatic patients was first proposed by Gupta, who found heterogeneity of response to bronchodilator in patients with different imaging cluster 92 (Figure 5).…”

Evaluating small-airways disease in asthmatic patients: The utility of quantitative computed tomography

“…With the advent of fast multidetector scanners and techniques for low-dose computed tomographic (CT) scan acquisition, thoracic QCT, although not capable of visualizing the small airways directly because of inadequate resolution, has nonetheless enabled investigators to assess the structure of the small airways indirectly. 2 Small-airways dysfunction results in maldistribution of ventilation, with reduced ventilation in regions of the lung leading to reflex vasoconstriction and thereby resulting in regional decreases in lung attenuation on inspiratory CT images. The heterogeneity of lung attenuation on inspiratory CT scans is accentuated in expiratory scans because of regional differences in small-airways closure with visual evidence of a mosaic or geographic pattern of gas trapping.…”