Radiology in diffuse parenchymal lung disease and lung nodules

It is a privilege and honour to introduce a new series entitled “Radiology” that is starting in this issue of the European Respiratory Review (ERR). The series focuses on diagnostic imaging and we are sure it will be of great interest for physicians dealing with both diffuse parenchymal lung disease (DPLD) and lung nodules. Indeed, the management of DPLD and incidentally identified lung nodules on computed tomography (CT) is, to say the least, difficult. Diagnostic uncertainty and variation in choice of treatment or follow-up among pulmonologists, radiologists and pathologists are common sources of clinical discussion. The arena of DPLD and incidental lung nodules is topical and both are the subject of recently published or to-be-published guidelines [1, 2].

To those already working in the field of DPLD, it will be abundantly clear that diagnostic uncertainty (based on a review of clinical data, high-resolution computed tomography (HRCT) appearances and/or the pathological findings) is part and parcel of the clinical challenge. The benefits of a multidisciplinary approach to the management of patients with DPLD are well known [1, 3, 4]. This is perhaps most important for the more complex cases and this, needless to say, mandates quality criteria for a multidisciplinary diagnosis. A tantalising insight into the workings of a multidisciplinary team is provided in the current issue of the ERR by Walsh [5], who discusses the more challenging (and, sometimes, perplexing) aspects of the inter-specialty discussion. The author highlights the role of HRCT and the dynamic nature of the diagnostic process incorporating clinical and morphological findings.

Another important aspect of management in DPLD is the issue of follow-up. Accordingly, Elicker et al. [6] will discuss the role of follow-up HRCT, which is underscored by recent guidelines [1, 7]. Indeed, longitudinal data, including the results of HRCT studies, suggest that disease “behaviour” over time provides useful diagnostic information. This is particularly true of “outlier” cases or in patients with incomplete diagnostic information (for instance, in those subjects in whom surgical lung biopsy is not feasible).

The article by Robbie et al. [8] will complete the circle by presenting some of the current thinking about HRCT in usual interstitial pneumonia/idiopathic pulmonary fibrosis. If not already in the mainstream, the term quantitative CT is likely to become increasingly familiar, to pulmonologists and radiologists alike, in the next 5–10 years. Data from different sources suggest that the prognostic “signal” from computer-based analyses of HRCT images is stronger than that based on the more traditional visual assessment [9, 10]. This is likely to be of interest to many but especially to those charged with drug development and to clinical trials co-ordinators, for whom accurate stratification of disease extent and morphological characterisation are a sine qua non. Tools for quantitative analysis of imaging studies are now almost routinely provided by the major CT manufacturers and it seems likely that the next decade will see a significant expansion in applications of computer-generated CT analyses in clinical practice.

Also to be included in this series is the forthcoming article by Larici et al. [11]. Fuelled somewhat by data from lung cancer screening trials (including the National Lung Screening Trial in the USA, as well as European studies), there has been a global increase in the awareness of incidental lung nodules and, more importantly, what to do with them. Guidelines for the follow-up and management of nodules have been published by, among others, the Fleischner Society and the British Thoracic Society [2, 12]. Larici et al. [11] will tackle the issues that govern lung nodule management. Notably, they will emphasise the features, other than size, which might be of greatest importance when deciding on the optimal follow-up strategy.

It is our hope that readers will find the articles in this series both informative and of specific value to their own practice. We believe that these will not only build on existing knowledge but also familiarise readers with the prospects and challenges in the challenging arena of DPLD and lung nodules.

Disclosures