Diffentiating between UIP and NSIP

  • Although less common than UIP, non-specific idiopathic pneumonia (NSIP) is still the most frequent differential diagnosis of UIP. On high-resolution CT the patterns of both conditions overlap considerably, complicating the diagnosis.13,16
  • Some distinct imaging features favour the diagnosis of NSIP over UIP. These include homogeneous lung involvement without an obvious apico-basal gradient, extensive ground-glass abnormalities that do not progress to areas of honeycombing, a finer reticular pattern, and micronodules.13,16
  • Although the different distribution and CT patterns may point to either UIP or NSIP, distinguishing these conditions remains challenging, and a lung biopsy is a necessary measure for clarification.13
Diffentiating between UIP and NSIP (adapted from Mueller-Mang 2007)