Background: Computed tomographic angiography (CTA) is the first-line imaging modality used for cerebral aneurysms because of its speed and sensitivity for detection, though digital subtraction angiography is often required for more detailed aneurysm shape delineation.
Objective: To determine if a sharper CTA reconstruction kernel can better characterize an aneurysm and improve decision-making prior to intervention.
Methods: 15 patients presenting with aneurysmal subarachnoid hemorrhage underwent 64-row CTA. CTA data were reconstructed using the default H20f smooth kernel and a H60f sharp kernel and compared to contemporaneous catheter three-dimensional rotational angiography (3DRA). Aneurysm neck, width, and aspect ratio measurements were made using intensity line-plots of identical projections on all imaging datasets and compared by matched-pair statistics.
Results: Aneurysm neck measurements from the H20f smooth kernel revealed overestimation compared to both the sharp kernel (greater by 0.64+/-0.21 mm, p < 0.01) and 3DRA (greater by 0.68+/-0.19 mm, p < 0.01). There was no statistically significant difference between 3DRA and the sharp kernel CTA measurements. Neck measurements correlated well between the H60f kernel and 3DRA but not between the H20f Kernel and 3DRA (R 0.97 vs. 0.86).
Conclusion: H60f sharp CTA kernel reconstruction provides more accurate anatomic characterization of cerebral aneurysms than the H20f smooth kernel at the expense of less visually pleasing reconstructions. Because it does not require additional contrast, radiation, or imaging hardware and is more akin to 3DRA, it may aid in selecting the appropriate treatment strategy prior to evaluation by catheter-based angiography.
From: Benefit of a Sharp Computed Tomography Angiography Reconstruction Kernel for Improved Characterization of Intracranial Aneurysms by O’Meara et al.