Reticulonodular interstitial airspace opacities
Reticulonodular interstitial opacities describe a chest imaging pattern made of interlacing linear (reticular) markings plus small spot-like densities (nodular) within the lung parenchyma. [1] This pattern is a radiologic description of interstitial involvement, not a single disease diagnosis. [1]
Terminology: reticular plus nodular pattern
A reticulonodular pattern represents combination of a reticular (linear) and a nodular (small discrete) pattern on imaging. [1] This combination reflects interstitial structural abnormalities that produce both linear and small density components. [1]
Imaging modality and appearance
The term is commonly used on chest radiograph and CT to characterize diffuse or regional parenchymal opacities. [1] On CT, crossing of a reticular network can create focal thickening that contributes to a reticulonodular appearance. [2]
Clinical meaning
Reticulonodular interstitial opacities are associated with a variety of interstitial lung disorders and other conditions affecting the lung interstitium. [1] The underlying cause is determined by the broader imaging distribution (for example, peripheral vs central, upper vs lower lobe, presence of traction bronchiectasis), symptoms, and laboratory data. [1]
Common differential diagnoses
Reticulonodular patterns can be seen in chronic interstitial lung diseases and in conditions that produce interstitial inflammation or fibrosis. [1] The specific differential diagnosis varies by patient context and the full imaging report. [1]