A system and method for automatically segmenting bone regions from Computed Tomography Angiography (CTA) volume data is disclosed. A locally operated bone detector distinguishes between bone regions and contrast agent filled vessels. A filtering operator removes small noise from the detected bone regions. A dilator expands the filtered detected bone regions to adjacent trabecular bones. A processor applies the dilated detected bone regions to the CTA volume data. A display shows the applied CTA volume data.