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Invest Radiol. 2015 May;50(5):361-5. doi: 10.1097/RLI.0000000000000134.

Color-coded cerebral computed tomographic angiography: implementation of a convolution-based algorithm and first clinical evaluation in patients with acute ischemic stroke.

Author information

1
From the *Institute for Clinical Radiology, †Josef Lissner Laboratory for Biomedical Imaging, Institute for Clinical Radiology, Departments of ‡Neurology, and §Neuroradiology, Ludwig Maximilians University Hospital Munich; and ∥Siemens AG, Healthcare Sector, Erlangen, Germany.

Abstract

OBJECTIVE:

The objective of this study was to develop a new method of displaying dynamic cerebral computed tomographic (CT) angiography (CTA) data sets in which the time delay to maximum enhancement (Tdelay) is displayed in a range of colors (color-coded CT angiography [cCTA]).

MATERIALS AND METHODS:

This institutional review board-approved study included multiparametric CT data sets from 16 patients with different types of supra-aortic large vessel occlusions. Color-coded CT angiography was reconstructed from CT perfusion raw data sets. All voxel enhancement curves were fitted to f(t) = α · AIFmtt(t - Δt), with AIFmtt(t), indicating enhancement of AIF dilated by convolution with boxcar function (with mean transit time [mtt]); α, scaling factor; and [INCREMENT]t, transition along the time. The time delay to maximum enhancement was defined as Tdelay = Δt +0.5 · mtt. Values of Tdelay were color-coded and superimposed on temporal maximum intensity projections CTA resulting in colored angiographic composite images. For a pilot clinical evaluation, diagnostic confidence in determining the pathology, quality of the visualization of leptomeningeal collaterals, and additional diagnostic information were assessed.

RESULTS:

The reconstruction of cCTA was technically feasible in all 16 patients. Both diagnostic confidence (P < 0.01) and the quality of the visualization of collaterals (P < 0.0001) were significantly higher when using the combination of single-phase CTA and cCTA compared with single-phase CTA alone. Additional diagnostic information was obtained with cCTA regarding occlusion type (reader 1: 5 cases and reader 2: 4 cases), differentiation between arteries and veins (11/13), differentiation between antegrade and retrograde filling (12/13), as well as leptomeningeal collateralization (13/14).

CONCLUSIONS:

Color-coded CT angiography is a technically feasible technique that provides additional information on cerebral hemodynamics in ischemic stroke patients.

PMID:
25591128
DOI:
10.1097/RLI.0000000000000134
[Indexed for MEDLINE]

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