Nasal cycle

The nasal cycle is a normal physiological process that occurs in the nasal cavity characterized by alternating partial congestion and decongestion of the nasal venous sinusoids of the nasal turbinates.

Radiographic features

CT

The nasal cycle is often seen on CT scan of the paranasal sinuses as unilateral smooth thickening of the nasal turbinates with preservation of the surrounding air channels (nasal meatus).

Differential diagnosis

The nasal cycle should not be confused with rhinitis, in which thickening of the nasal turbinates is more irregular and the air channels are obliterated.