Present and future utility of computed tomography scanning in the assessment and management of COPD

Abstract

likely to have important implications for understanding disease progression and the future management of this condition [2]. There are currently no significant diseasemodifying medications for COPD and there have not been the improvements in outcome seen in other chronic diseases. Other tools are required in addition to spirometry to help explain the heterogeneity and provide further insights into approaches to study and treat COPD. CT has current practical applications in the routine management and investigation of the disease and with the development of novel analysis techniques has the potential to provide further details about the pulmonary and extra-pulmonary manifestations of COPD. Computed Tomography in Current Clinical PractisePrior to the 1970s histological and post mortem studies were required to study structural changes of the lung. The introduction of CT made it possible to visualise the thorax and assess lung structure non-invasively. In COPD CT can identify key morphological features, including emphysema, bronchial wall thickening and gas trapping. These pathologies contribute directly to airflow obstruction and therefore CT has the potential to provide vital insights into the underlying pathophysiological changes of COPD. Despite this, routine CT imaging has not necessarily been widely adopted in clinical practise and its place in the management and investigation of COPD has not been firmly established. The GOLD guidelines do not routinely recommend CT scanning in COPD and only advise that it may be helpful in differential diagnosis or when surgical options are being considered [3]. This general ambivalence is highlighted by a study of attitudes in respiratory physicians and surgeons in the UK where only 32% thought it necessary for patients with severe COPD to have a CT scan [4].There are a number of reasons why the use of CT has not become routine in COPD. One of the most important is the perceived notion that using CT does not alter management, although this is not strictly true. The National Emphysema Treatment Trial (NETT) demonstrated that patients with advanced upper lobe emphysema and limited exercise ability improved after lung volume reduction surgery [5]. There has also been considerable progress and experience in using endobronchial treatments for severe emphysema including coils, valves, sealant and airway bypass. In the correct patients with severe heterogeneous emphysema these treatments can lead to significant improvement in pulmonary physiology and functional capacity [6, 7]. CT imaging can also identify bullous disease, which may be amenable to surgery and bullectomy can lead to improved health status [8]. It therefore seems clear that patients with severe COPD require CT imaging to determine which patients are appropriate for these techniques.CT imaging can also detect concomitant pulmonary pathology in COPD. Bronchiectasis is particularly prevalent, with studies demonstrating 50% of COPD patients having CT evidence of the disease [9][10][11]. When present bronchiectasis is asso...

Distinct emphysema subtypes defined by quantitative CT analysis are associated with specific pulmonary matrix metalloproteinases

“…Efforts have been made to study emphysema in more objective detail using CT image analysis and threshold-based quantification methods, such as %LAA <-950 are the current standard [ 7 ]. These techniques do not provide any information about emphysema sub-types, whereas local histogram-based emphysema (LHE) quantification is a novel method, which uses regional histogram data to quantify different emphysema sub-types on CT images [ 2 ].…”

Objective quantitative multidetector computed tomography assessments in patients with combined pulmonary fibrosis with emphysema: Relationship with pulmonary function and clinical events

“…Physiological measurements of lung function have been conventionally performed to evaluate disease severity in patients with lung disease. However, computer-based HRCT image analysis has greatly improved, and has enabled us to assess the extent of lung disease and to quantify morphological changes [ 54 , 55 ]. The recently introduced densitometric- and histogram-based analysis of CT images provides data on mean lung attenuation, skewness, and kurtosis.…”

Quantifizierung von Ventilation, Inflammation, Perfusion und Struktur (VIPS)

“…Insbesondere bei der COPD wurden mehrere Parameter evaluiert, welche eine Quantifizierung unterschiedlicher Aspekte der Lungenstruktur und damit eine Differenzierung unterschiedlicher COPD-Phänotypen ermöglichen [36,37]. Die meisten Erfahrungen liegen hierbei in der Quantifizierung des Emphysems vor [5].…”