Superior performance of cone-beam CT angiography in characterization of intracranial atherosclerosis

Abstract

Object. Intracranial atherosclerotic disease (ICAD) carries a high risk of stroke. Evaluation of ICAD has focused on assessing the absolute degree of stenosis, although plaque morphology has recently demonstrated increasing relevance. The authors provide the first report of the use of ultra-high-resolution C-arm cone-beam CT angiography (CBCT-A) in the evaluation of vessel stenosis as well as plaque morphology.Methods. Between August 2009 and July 2012, CBCT-A was used in all patients with ICAD who underwent catheter-based angiography at the authors' institution (n = 18). Lesions were evaluated for maximum degree of stenosis as well as plaque morphological characteristics (ulcerated, calcified, dissected, or spiculated) via digital subtraction angiography (DSA), 3D-rotational angiography (3DRA), and CBCT-A. The different imaging modalities were compared in their assessment of absolute stenosis as well as their ability to resolve different plaque morphologies.Results. Lesions were found to have similar degrees of stenosis when utilizing CBCT-A compared with 3DRA, but both 3DRA and CBCT-A differed from DSA in their assessment of the absolute degree of stenosis. CBCT-A provided the most detailed resolution of plaque morphology, identifying a new plaque characteristic in 61% of patients (n = 11) when compared with DSA and 50% (n = 9) when compared with 3DRA. CBCT-A identified all lesion characteristics visualized on DSA and 3DRA.Conclusions. CBCT-A provides detailed spatial resolution of plaque morphology and may add to DSA and 3DRA in the evaluation of ICAD. Further prospective study is warranted to determine any benefit CBCTA-A may provide in clinical decision making and risk stratification over existing conventional imaging modalities. This article contains some figures that are displayed in color on line but in black-and-white in the print edition. M. G. Safain et al. 442J Neurosurg / Volume 121 / August 2014 cranial stent placement during aneurysm treatment, 20,22 and delineate cerebral 15,16 and spinal arteriovenous malformations.1 Furthermore, CBCT-A has since been shown to have excellent spatial resolution of the intracranial vasculature, including the ability to resolve submillimeter objects such as stent struts measuring 50-70 µm. 13Despite these uses of CBCT-A in evaluation of intracranial vessels, its utility in determining stenosis and plaque morphology in ICAD has not been previously evaluated.Given the high spatial resolution provided by CBCT-A, we have, since August 2009, obtained imaging studies in all patients undergoing catheter-based angiography for ICAD using this modality, in addition to contemporaneous standard DSA and 3DRA. We sought here to compare and quantify the resolution of CBCT-A compared with 3DRA as well as DSA in the evaluation of ICAD. We present the initial report of additional plaque characteristics identified by CBCT-A in patients with ICAD. Methods Case SelectionDuring the study time period of August 2009 to July 2012, all patients undergoing catheter-based angiography for the ...

Treatment and imaging of intracranial atherosclerotic stenosis: current perspectives and future directions

“…CBCT‐A is an invasive catheter‐based modality with a radiation dose similar to that of conventional CTA. CB‐CTA did not differ significantly in assessing the absolute percent stenosis of lesions when compared with other 3D modalities such as 3D rotational angiography (Safain et al., ). However, both CB‐CTA and 3D rotational angiography differed in the measurement of percent stenosis when compared with traditional 2D‐DSA (Safain et al., ).…”

“…CB‐CTA did not differ significantly in assessing the absolute percent stenosis of lesions when compared with other 3D modalities such as 3D rotational angiography (Safain et al., ). However, both CB‐CTA and 3D rotational angiography differed in the measurement of percent stenosis when compared with traditional 2D‐DSA (Safain et al., ). Since intracranial stenosis is a three‐dimensional phenomenon, it is possible that CB‐CTA and 3D rotational angiography are more accurate than standard 2D‐DSA.…”

“…Since intracranial stenosis is a three‐dimensional phenomenon, it is possible that CB‐CTA and 3D rotational angiography are more accurate than standard 2D‐DSA. However, these findings from a single study (Safain et al., ) need further validation with DSA in a prospective manner.…”

“…On two‐dimensional (2D) DSA, the severity of stenosis is quantified as a ratio between the wall diameter at the point of maximum narrowing and the reference diameter of the proximal normal artery (Samuels, Joseph, Lynn, Smith, & Chimowitz, ). Studies about intra‐ and extracranial stenosis suggest that 2D‐DSA may incorrectly estimate true stenosis when its findings are compared with those of other imaging modalities (such as 3D‐rotational angiography or high‐resolution CTA) as well as measurements in histological specimens (Netuka et al., ; Safain et al., ). Vessel stenosis due to plaque occurs in three dimensions and with 2D‐DSA these spatial features are flattened.…”

“…A recent study with 18 patients with intracranial atherosclerosis has shown superior performance of high‐resolution CT angiography over 2D‐DSA and 3D‐rotational angiography in characterization of plaque morphology (such as ulceration, calcification, dissection of the plaque, and core protrusion into the vessel lumen). Compared to high‐resolution CTA, such lesions are missed in 61% ( n = 11) when evaluation of intracranial atherosclerosis is done with 2D‐DSA, and in 50% of patients ( n = 9) with 3D‐rotational angiography (Safain et al., ).…”