Abstract
Objective: Pre-operative detection of mastoid emissary veins using HRCT and standard CT in retrosigmoid craniotomy planning, which is used to access the cerebellopontine angle area. Methods: A total of 100 native CT scans (4.5 mm thick slices) and 100 CT scans in thin slices - HRCT (1 mm thick slices) were evaluated.
Images were obtained from the PACS Information System of the Faculty Hospital in Olomouc (FNOL). We evaluated and compared individual occurence of mastoid emissary vein in standard CT and HRCT scans on both sides, left and right, and we were interested in the sensitivity of the examination depending on the size of bone canal for the vein, i.e. mastoid foramen.
Results: In the native CT scan, there was no emissary visible in 71 cases on the right and 62 cases on the left. One emissary was visible in 28 cases on the right and 36 cases on the left.
More than one was a relatively rare case and it was formed by significant connections wider than 3.5 mm. HRCT provides a higher detection sensitivity for small emissaries, which were mostly invisible in a standard CT scan, in this case it was also possible to detect a relatively rare case of 3-4 mastoid foramina.
While the difference is not statistically significant when the emissaries are larger than 3 mm, in emissaries with the width of channel less than 2 mm it already becomes statistically significant. Conclusion: Benefit of HRCT in ret-rosigmnoid craniotomy planning is indisputable and helps to eliminate many potential complications.