Fourier analysis of intracranial aneurysms: towards an objective and quantitative evaluation of the shape of aneurysms

Abstract

Shape irregularities of intracranial aneurysms may indicate an increased risk of rupture. To quantify morphological differences, Fourier analysis of the shape of intracranial aneurysms was introduced. We compared the morphology of 45 unruptured (UIA) and 46 ruptured intracranial aneurysms (RIA) in 70 consecutive patients on the basis of 3D-rotational angiography. Fourier analysis, coefficient of roundness and qualitative shape assessment were determined for each aneurysm. Morphometric analysis revealed significantly smaller coefficient of roundness (P < 0.02) and higher values for Fourier amplitudes numbers 2, 3 and 7 (P < 0.01) in the RIA group, indicating more complex and irregular morphology in RIA. Qualitative assessment from 3D-reconstructions showed surface irregularities in 78% of RIA and 42% of UIA (P < 0.05). Our data have shown significant differences in shape between RIA and UIA, and further developments of Fourier analysis may provide an objective factor for the assessment of the risk of rupture.

3D Shape Analysis of Intracranial Aneurysms Using the Writhe Number as a Discriminant for Rupture

“…Some of the first morphological indexes, such as non-sphericity, ellipticity, and undulation were proposed by Raghavan et al 16 and studied further in subsequent studies. 4,9 Rohde et al 17 applied Fourier analysis to capture the shape irregularities of intracranial aneurysms. Their Fourier analysis was performed on 2D data sets.…”

“…To this end, we introduce a series of original shape descriptors based on the writhe number. 6 Similar to recent morphological studies, 9,12,13,16,17 the rupture status prediction is performed on a data set of aneurysms, which were labeled as being ruptured or not at the time of detection by the treating neurosurgeons. In the proposed methodology, aneurysms are isolated from the segmented vasculature represented as a 3D triangular mesh.…”

Geometric Parameter Analysis of Ruptured and Unruptured Aneurysms in Patients with Symmetric Bilateral Intracranial Aneurysms: A Multicenter CT Angiography Study

“…[19][20][21] Recently, a large-cohort prospective study found that unruptured aneurysms with a daughter sac (an irregular protrusion of the wall of the aneurysm) are more likely to rupture than aneurysms with a regular shape.…”

Predictible morfometric parameters for ruptrue of intracranial aneurysms – series of 142 operated aneurysms

“…The aim of Rohde's research and analysis was to identify whether those aneurysms were lobular or daughter aneurysms. Up until that date conventional angiography was insufficient to make this differentiation (19). Dhar et al performed a detailed analysis of the morphometric ratios of the aneurysm and this particular type of procedure was previously not possible with conventional angiography (8).…”

“…Thanks to the well-developed software and the rotational angiography they were able to work on the assessment of irregularities to identify whether it is in a lobus or a daughter aneurysm. Conventional angiography is insufficent to show this difference (19).…”