Guideline Recommendations and Real-World Practice

In interstitial lung disease (ILD), the gap between evidence-based guideline algorithms and real-world clinical practice is arguably widest when it comes to diagnostic recommendations. Guideline algorithms are necessarily concise: the use of guideline categories for high-resolution CT (HRCT) appearances provides a coherent approach that simplifies the spectrum of HRCT findings. In the words of William James, a founder of the pragmatic school of philosophy, "the art of being wise is the art of knowing what to overlook." This is exemplified by the widely used HRCT categories recommended in current guidelines for the diagnosis of idiopathic pulmonary fibrosis (IPF): typical usual interstitial pneumonia (UIP), probable UIP, indeterminate, and indicative of an alternative diagnosis.