Juxtaphrenic peak sign

Last revised by Calum Worsley on 1 Jan 2025

The juxtaphrenic peak sign, also known as diaphragmatic tenting or Kattan sign, refers to the peaked or tented appearance of a hemidiaphragm which can occur in the setting of lobar collapse or post lobectomy (lung). It is caused by retraction of the lower end of diaphragm at an inferior accessory fissure (most common 1), major fissure or inferior pulmonary ligament. It is commonly seen in collapse of the left or right upper lobes but may also be seen in middle lobe collapse.

History and etymology

It was first described by Kenneth R Kattan (1926-2015), an American radiologist from Cincinnati, Ohio, and his colleagues in 1980 6.

Cases and figures

  • Case 1: in LUL collapse
  • Case 2
  • Case 3: on right with RUL collapse
  • Case 4: post tuberculosis
  • Case 5
  • Case 6
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