Otosclerosis - Veillon classification of otosclerosis

Otosclerosis is a primitive dystrophia of the temporal bone that leads to abnormal bone growth. Veillon classification divides sites and extension of otosclerosis based on finding on HRCT of the temporal bone into 6 types.

Type Description
Ia isolated thickening of the footplate hypodensity
Ib isolated anterior fenestral hypodensity <1mm (AFH)
II isolated anterior fenestral hypodensity >1mm (AFH)
III anterior fenestral hypodensity >1mm, hypodensity extends to the endosteum of cochlea
IVa hypodense foci in the entire middle layer of the otic capsule: pericochlear hypodensity (PH), internal auditory canal hypodensity (IACH)
IVb involvement of the entire otic capsule including the vestibule and semicircular canals


1. Veillon F, Stierle JL, Dussaix J, et al.: Imagerie de l’otospongiose : confrontation clinique et imagerie. Journal de radiologie 2006;87(11-C2):pp 1756-1764
2. Lagleyre S, Sorrentino T, Calmels MN, et al. Reliability of High-Resolution CT Scan in Diagnosis of Otosclerosis. Otology & Neurotology 2009;30:1152-1159.
3. Slavikova K, Liskova Y, Malik M., et al. Zobrazovacie metody pri otoskleroze - skusenosti. Ces Radiol 2013;67(3):214-220.