Trochlear cistern of the cavernous sinus: an anatomical study using magnetic resonance imaging

The present study aimed to explore the trochlear cistern (TC) of the cavernous sinus using magnetic resonance imaging (MRI).

Following conventional MRI examination, a total of 73 patients underwent the constructive interference steady-state (CISS) sequence in thin-sliced coronal sections. Moreover, three injected cadaver heads were dissected.

In the cadaver specimens, the extent of the TC was difficult to identify on any dissected side. On the CISS images, the TC was identified in 98.6% on the right side and 94.5% on the left, while transmitting the trochlear nerve (TN) was identified in 83.6% on the right and 79.5% on the left. Most TNs were delineated as a single trunk, while duplication of the nerve was found in 3% of cases. The TC, commonly located inferior or inferolateral aspect of the oculomotor trigone. The size and extent of TC were highly variable. The TN location in the TC was also variable and was identified throughout the upper, middle, and lower parts of the TC. Moreover, relationships between the TC and Meckel's cave were highly variable.

TC shows morphological variability. The coronal CISS sequence is useful for exploring TC and TN in clinical practices.