gms | German Medical Science

Objective: Early detection and treatment of cerebral hypoperfusion as a consequence of posthemorrhagic vasospasm in patients with subarachnoid hemorrhage is a major challenge. While CT angiography may show vasospastic vascular segments, perfusion imaging is necessary to estimate the hemodynamic effect, especially in cases of only moderate vasospasm. We have developed a method which allows calculating the volume of whole vascular segments. The aim of the present study was to analyze whether the volume of the M1 segment could be used as a marker of hypoperfusion.

Method: In 24 consecutive patients that were admitted to our neurosurgical department with an aneurysmal subarachnoid hemorrhage between 1 October 2011 and 31 March 2012 14 patients were identified who had obtained more than 3 CT angiographies and perfusion CTs. Amira software (FEI) was used to reconstruct the virtual vascular tree. The M1 segment was identified and its volume was segmented from the data set and expressed as M1 volume/ M1 length. Perfusion CTs were independently reviewed for hypoperfusion by a neuroradiologist.

Results: 70 image sets were analyzed. M1 volumes ranged from 2.6 to 15.1 μl/mm (mean 7.8 μl/mm ±3.2 μl/mm). 9 perfusion CTs with hypoperfusion of an ACM territory were identified which had had the consequence of interventional vasospasm treatment. In all cases of hypoperfusion M1 volume was found to be <8.1 μl/mm, in 7 of 9 cases M1 volume was <5.6 μl/mm.

Conclusions: Volumetric analysis of the M1 segment can easily be performed using CTA imaging, and hypoperfusion is associated with small M1 volumes. Integration of volumetric analysis of the M1 segment into routine CTA could therefore provide a valuable new marker to estimate the hemodynamic relevance of vasospasms.