Thrombus hounsfield unit on CT predicts vascular recanalization in stroke patients Poster No.: C-2616 Congress: ECR 2010 Type: Scientific Exhibit Topic: Neuro Authors: H. F.Termes, J. Puig, J. Daunis-i-Estadella, G. Blasco, G. Laguillo, I. Boada, M. Castellanos, J. Serena, S. Pedraza; Girona/ES Keywords: stroke, thrombus, thrombolysis DOI: 10.1594/ecr2010/C-2616 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 44
Purpose Early vascular recanalization is essential for the successful treatment of acute stroke. Computed tomography (CT) can detect thrombi in arteries after acute stroke, and can provide a measure composition based on Hounsfield Units (HU). According to their fibrin and erythrocyte content, the thrombi are classified into red, white or mixed categories (Fig.1-3). Fig.: 1 References: Bayern Schering Pharma AG 2008 Page 2 of 44
Fig.: 2 References: Kirchhof K, Welzel T, Mecke C, et al. Differentiation of White, Mixed, and Red Thrombi: Value of CT in Estimation of the Prognosis of Thrombolysis-Phantom Study. Radiology 2003 228:126-130 Page 3 of 44
Fig.: 3 References: pathhsw5m54.ucsf.edu/cts/unknown16/thrombi.html Previous experimental studies have demostrated lower HU in platelet-rich thrombus than in erythrocyte-rich thrombus. Hemoglobin determines the attenuation of a clot and the lysability of a thrombus appears to increase with increasing hematocrit levels and, therefore, hemoglobin (Fig.4). In this respect, platelet-rich thrombus is resistant to thrombolytic drugs, but erythrocyte-rich thrombus is not. Page 4 of 44
Fig.: 4 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN In this study our purpose is to investigate whether the lysability of thrombi can be predicted by HU values in patients after middle cerebral artery (MCA) acute stroke. Images for this section: Page 5 of 44
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Methods and Materials Patients We retrospectively studied 23 patients (12 men, 11 women; mean age 69±12 years) with acute MCA hemispheric infarction within 6 hours of symptom onset from January 2004 to March 2005. We excluded patients with cerebral hemorrhage, significant preexisting nonischemic neurological deficit, or a history of prior stroke. The study was approved by the local ethics committee. All patients or their relatives provided informed written consent. Patients underwent neurological examination, including National Institutes of Health Stroke Scale (NIHSS) score, by a certified neurologist at admission and at day 3. Imaging All of the patients underwent 2 mm section noncontrast CT using 16 multidetector row CT scanner (Philips MX8000) prior to receive thrombolysis. CT angiography (CTA) was subsequently obtained using the same thickness of 2 mm (Fig.1). CT data were transferred to an offline workstation for analysis. Page 10 of 44
Fig.: 1 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN HU were obtained by manually placing regions of interest (ROI) on the thrombus (Fig.2). Page 11 of 44
Fig.: 2 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN HU for each ROI were obtained by averaging all voxels within the ROI on the MCA affected and unaffected by the thrombus. The ipsilateral-to-contralateral MCA HU ratios were calculated (rhu=mcaaffected side/mcaunaffected side) in noncontrast CT after the thrombus confirmation on CTA images. The presented HU values are based on the average of the mean values obtained by two raters, who were fully blinded of clinical symptoms and imaging data. Follow-up imaging was obtained using magnetic resonance imaging within 3 days after symptom onset. Some examples of our preliminary study are shown (Fig.3-6, Fig.7-10, Fig.11-13). Page 12 of 44
Fig.: 3 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 13 of 44
Fig.: 4 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 14 of 44
Fig.: 5 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 15 of 44
Fig.: 6 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 16 of 44
Fig.: 7 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 17 of 44
Fig.: 8 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 18 of 44
Fig.: 9 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 19 of 44
Fig.: 10 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 20 of 44
Fig.: 11 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 21 of 44
Fig.: 12 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Page 22 of 44
Fig.: 13 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Statistical analysis Data are presented as mean (SD) values. To calculate the rhu cutoff point to discriminate between subjects with recanalization at day 3 from those without, we used linear discriminant analyses. P <.05 was considered to indicate a statistically significant differences. All statistical evaluations were performed using Minitab version 15.1.0.0 (Minitab Inc, State College, Pennsylvania). Images for this section: Page 23 of 44
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Results Thrombi were detected in all of patients on CT angiography and were identified on M1, M2 or M1 and M2 in 16 (69.6%), 5 (21.7%) and 2 patients (8,7%), respectively. Left-side was presented in 17 patients (73,9%). The NIHSS scores at admission and at day 3 were 14.8±4.5 and 12.5±8.2, respectively. The mean HU value of thrombus was 44.51±9.16 and the rhu bettween MCA affected and MCA unaffected was 1.36±0.21. There were significant differences between rhu of recanalized respect to no recanalized thrombi (p<0.001) (Fig.1). Fig.: 1 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Complete recanalization was detected in 8 cases (34,78%) of the occluded MCA. Page 37 of 44
The rhu cutoff point that best discriminated the absence of recanalization at day 3 was 1,32 (p<0.001). The discriminant analysis correctly identified 11 of 14 patients (78.0%) (Fig.2 ). Fig.: 2 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), were 100%, 75%, 78.6% and 100%, respectively. (Fig.3 ). Page 38 of 44
Fig.: 3 References: H. F.Termes; Radiology, Hospital Universitari de Girona Dr.Josep Trueta, Girona, SPAIN Images for this section: Page 39 of 44
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Conclusion Our preliminary study suggests that measurement of thrombus HU may be useful to help predict early vascular recanalization in stroke patients. This assessment can be used to select the most appropiate reperfusion strategy for individual patients. References Arnold M, Nedeltchev K, Schroth G, et al. Clinical and radiological predictors of recanalisation and outcome of 40 patients with acute basilar artery occlusion treated with intra-arterial thrombolysis. J Neurol Neurosurg Psychiatry 2004; 75:857-862. Arnold M, Nedeltchev K, Remonda L, et al. Recanalisation of middle cerebral artery occlusion after intra-arterial thrombolysis: different recanalisation grading systems and clinical functional outcome. J Neurol Neurosurg Psychiatry 2005; 76:1373-1376. Kim EY, Lee SK, Kim DJ, et al. Detection of Thrombus in Acute Ischemic Stroke. Value of Thin-Section Noncontrast-Computed Tomography. Stroke 2005; 36:2745-2747. Kirchhof K, Welzel T, Mecke C, et al. Differentiation of White, Mixed, and Red Thrombi: Value of CT in Estimation of the Prognosis of Thrombolysis- Phnatom Study. Radiology 2003; 228: 126-130. Kucinski T, Koch C, Grzyska U, et al. The Predictive Value of Early CT and Angiography for fatal Hemispheric Swelling in Acute Stroke. AJNR 1998; 19:839-846. Lam W, Leung T, Chu W, et al. Early computed features in extensive middle cerebral artery territory infarct: prediction of survival. J Neurol Neurosurg Psychiatry 2005; 76:354-357. Manelfe C, Larrue V, von Kummer R, et al. Association of Hyperdense Middle Cerebral Artery Sign With Clinical Outcome in Patients Treated With Tissue Plasminogen Activator. Stroke 1999; 30: 769-772. Personal Information Page 43 of 44
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