[Measurements of semicircular canal space direction with MRI]

Measure the space direction of semicircular canals to provide the anatomical basis for the diagnosis and treatment of BPPV.

We calculated angles among semicircular canals of 24 patients using MRI scaning with 3D-CISS sequence.

The angle between the left and right posterior semicircular canals was 106.61 degress ± 8.58 degrees, so the angle among the posterior semicircular canals and sagittal head plane was 53.31 degrees ± 4.29 degrees. Pairs of contralateral synergistic canal planes were not parallel, forming 171.67 degrees ± 4.36 degrees between the left and right horizontal semicircular canal planes, 154.37 degrees ± 10.87 degrees between the left posterior and right anterior semicircular canal planes and 156.84 degrees ± 9.34 degrees between the right posterior and left anterior semicircular canal planes.

Our measurement of the angles among semicircular canals coincided with those of previous reports. The angles between contralateral synergistic canal planes were close to parallel, but the angle between the posterior semicircular canals and sagittal head plane was great than 45 degrees that traditionally thought to be.