Critical role of angiographic acquisition modality and reconstruction on morphometric and haemodynamic analysis of intracranial aneurysms

Abstract

The choice of catheter 3D angiographic modality and reconstruction kernel has a critical impact on derived aneurysm morphological and haemodynamic analysis. The resultant variability can confound and obscure underlying differences within patient populations and between studies performed at different centres using divergent techniques, compromising the accuracy of quantitative aneurysm analysis.

How to Size Intracranial Aneurysms: A Phantom Study of Invasive and Noninvasive Methods

“…15 Regarding MDCTA, a sharp reconstruction kernel is thought to lead to very exact aneurysm imaging compared with a smooth kernel, and if a 3D DSA was used as the criterion standard what could not been proved in our study because in our setting 3D DSA also overestimated aneurysm sizes. 13 However, the use of different reconstruction kernels does play a critical role in not only MDCTA but also 3D-DSA as has been described recently by Lauric et al 12 In this study, different kernels were used for different purposes, and we found 3D-DSA VRT and MPR images from smooth/normal kernel reconstructions to overestimate aneurysm sizes, in line with findings of Lauric et al 12 recently. Most interesting, Lauric et al and O'Meara et al 13 compared different techniques and different reconstruction kernels with 3D-DSA images, which we found to significantly overestimate aneurysm sizes and therefore were not recommended for use as a criterion standard in aneurysm sizing.…”

“…However, until recently, there were no guidelines or consensus on how intracranial aneurysm sizing should be performed, and only a few studies have focused on this issue though there is growing evidence for the importance of the chosen image technique and reconstruction method applied. [12][13][14] Considering the above-mentioned dimension of 1-mm deviation to be clinically relevant, our study revealed 2D-DSA images adjusted to previous 3D DSA (optimal projection) performed the best in terms of accuracy when comparing the absolute mean difference and SD of the aneurysm dimensions with Ϫ0.07 Ϯ 0.61 for aneurysm 1 and 0.12 Ϯ 0.25 for the second aneurysm model. Therefore, all other techniques in this study were compared with this predefined criterion standard.…”

Visualization of stent apposition after stent-assisted coiling of intracranial aneurysms using high resolution 3D fusion images acquired by C-arm CT

“…Some error may have been introduced in the measurements of distance between the stent and vessel wall in the crescent sign due to manual windowing of the images. Similarly, the reconstruction parameters were not standardized and could potentially affect the visibility of the stent structures and vessels 18. Diameters and lengths of the deployed stents were not the same for each stent type due to their commercial availability.…”

4D-CT angiography versus 3D-rotational angiography as the imaging modality for computational fluid dynamics of cerebral aneurysms

“…However, overall there is a lack of consistency with CFD methods causing inconsistent results which is hindering their use clinically 8 24. Variability may be derived from different sources including imaging modality quality (3D-RA vs CTA vs MRA),9 10 15 25 segmentation methods (ie, watershed vs threshold-based),4 solver settings,26 27 and/or boundary condition assumptions or estimations made 28. Although 3D-RA imaging is regarded as the gold standard for CFD assessment due to its superior image quality, it too comes with a number of limitations including its invasiveness and lack of patient-specific flow rates.…”

“…To improve spatial resolution, volumes were reconstructed using a 50% size FOV and a 384 mm 3 matrix to include the aneurysm, parent artery, and outlet vessels, producing imaging with an isotropic resolution between 0.15 mm 3 and 0.35 mm 3 . A normal reconstruction kernel was used as previous groups have shown that reconstruction of 3D-RAs with a sharp kernel causes high-frequency noise content that results in insufficient quality for accurate segmentation 15…”