Katarzyna Wanda Sklinda MD, Abstract Co-Author: Nothing to Disclose

Jerzy Michal Walecki MD, Presenter: Nothing to Disclose

Artur Przelaskowski DSC, Abstract Co-Author: Nothing to Disclose

Michal Maciej Mol MD, Abstract Co-Author: Nothing to Disclose

Tomasz Jacek Bulski, Abstract Co-Author: Nothing to Disclose

Computed tomography (CT) plays a crucial role in the evaluation of stroke patients; however, its often bellow par in extracting hypodensities associated with cytotoxic edema in the hyperacute stage. We propose additional wavelet and curvelet based post-processing methods of extracting hypodensities in CT scans of hyperacute stroke patients. The aim of this study was to assess the usefulness of wavelet and curvelet based post-processing in depiction of hypodensities in CT scans of acute stroke patients.

Retrospective evaluation of 115 sets of examinations conducted in patients admitted with symptoms suggestive of stroke was undertaken by four radiologists unaware of the final clinical findings. All of the selected cases were considered as having no direct signs of hyperacute ischemia in the localization corresponding with clinical manifestation and follow-up studies. In the first stage only the scans performed at the admission were evaluated, after a month the same scans were evaluated again with the additional use of wavelet-based CAD support. Subtle tissue attenuation changes were investigated, denoised, extracted, and visualized. Follow-up CT scans and/or clinical picture confirmed or excluded the diagnosis. Basing on preliminary results and concluded efficiency limitations additional post-processing based on curvelet decomposition and improved segmentation of stroke susceptible regions has been designed and performed later on for selected examinations regarded as difficult.

A sensitivity of 0.641 and specificity of 0.688 was achieved for the wavelet-based stroke monitor aided diagnosis. Further enhancement of hypodensities based on improved stroke CAD support in diagnostically difficult cases increased the sensitivity and specificity of the diagnosis. Sensitivity for the 6 difficult cases increased from 0.5 to 0.91, and specificity – from 0.33 to 0.76.

Combining the results of CT and CAD support, yielded better recognition of ischemic regions in acute stroke patients. Planned, prospective studies will allow for evaluation of the impact on further treatment of hyperacute stroke patients.

Early and more accurate detection of ischemic brain regions, in the acute setting.

Sklinda, K, Walecki, J, Przelaskowski, A, Mol, M, Bulski, T, A CAD System for Improving the Diagnostic Value of Computed Tomography in the Setting of Hyperacute Stroke.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11005338.html