Background: Using flat-detector CT (FD-CT) for stroke imaging has the advantage that both diagnostic imaging and endovascular therapy can be performed directly within the Angio Suite without any patient transfer and time delay. Thus, stroke management could be speeded up significantly, and patient outcome might be improved. But as precondition for using FD-CT as primary imaging modality, a reliable exclusion of intracranial hemorrhage (ICH) has to be possible. This study aimed to investigate whether optimized native FD-CT, using a newly implemented reconstruction algorithm, may reliably detect ICH in stroke patients. Additionally, the potential to identify ischemic changes was evaluated. Methods: Cranial FD-CT scans were obtained in 102 patients presenting with acute ischemic stroke (n = 32), ICH (n = 45) or transient ischemic attack (n = 25). All scans were reconstructed with a newly implemented half-scan cone-beam algorithm. Two experienced neuroradiologists, unaware of clinical findings, evaluated independently the FD-CTs screening for hemorrhage or ischemic signs. The findings were correlated to CT, and rater and inter-rater agreement was assessed. Results: FD-CT demonstrated high sensitivity (95-100%) and specificity (100%) in detecting intracerebral and intraventricular hemorrhage (IVH). Overall, interobserver agreement (κ = 0.92) was almost perfect and rater agreement to CT highly significant (r = 0.81). One infratentorial ICH and 10 or 11 of 22 subarachnoid hemorrhages (SAHs) were missed of whom 7 were perimesencephalic. The sensitivity for detecting acute ischemic signs was poor in blinded readings (0 or 25%, respectively). Conclusions: Optimized FD-CT, using a newly implemented reconstruction algorithm, turned out as a reliable tool for detecting supratentorial ICH and IVH. However, detection of infratentorial ICH and perimesencephalic SAH is limited. The potential of FD-CT in detecting ischemic changes is poor in blinded readings. Thus, plain FD-CT seems insufficient as a standalone modality in acute stroke, but within a multimodal imaging approach primarily using the FD technology, native FD-CT seems capable to exclude reliably supratentorial hemorrhage. Currently, FD-CT imaging seems not yet ready for wide adoption, replacing regular CT, and should be reserved for selected patients. Furthermore, prospective evaluations are necessary to validate this approach in the clinical setting.

Berkhemer OA, Fransen PS, Beumer D, et al: A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015;372:11-20.
Goyal M, Demchuk AM, Menon BK, et al: Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015;372:1019-1030.
Campbell BC, Mitchell PJ, Kleinig TJ, et al: Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med 2015;372:1009-1018.
Kloska SP, Nabavi DG, Gaus C, et al: Acute stroke assessment with CT: do we need multimodal evaluation? Radiology 2004;233:79-86.
Scharf J, Brockmann MA, Daffertshofer M, et al: Improvement of sensitivity and interrater reliability to detect acute stroke by dynamic perfusion computed tomography and computed tomography angiography. J Comput Assist Tomogr 2006;30:105-110.
Broderick JP, Palesch YY, Demchuk AM, et al: Endovascular therapy after intravenous t-PA versus t-PA alone for stroke. N Engl J Med 2013;368:893-903.
Khatri P, Abruzzo T, Yeatts SD, et al: Good clinical outcome after ischemic stroke with successful revascularization is time-dependent. Neurology 2009;73:1066-1072.
Jovin TG, Chamorro A, Cobo E, et al: Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med 2015;372:2296-2306.
Gupta R, Cheung AC, Bartling SH, et al: Flat-panel volume CT: fundamental principles, technology, and applications. Radiographics 2008;28:2009-2022.
Kau T, Hauser M, Obmann SM, et al: Flat detector angio-CT following intra-arterial therapy of acute ischemic stroke: identification of hemorrhage and distinction from contrast accumulation due to blood-brain barrier disruption. AJNR Am J Neuroradiol 2014;35:1759-1764.
Struffert T, Deuerling-Zheng Y, Kloska S, et al: Flat detector CT in the evaluation of brain parenchyma, intracranial vasculature, and cerebral blood volume: a pilot study in patients with acute symptoms of cerebral ischemia. AJNR Am J Neuroradiol 2010;31:1462-1469.
Jauch EC, Saver JL, Adams HP Jr, et al: Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013;44:870-947.
Doelken M, Struffert T, Richter G, et al: Flat-panel detector volumetric CT for visualization of subarachnoid hemorrhage and ventricles: preliminary results compared to conventional CT. Neuroradiology 2008;50:517-523.
Struffert T, Eyupoglu IY, Huttner HB, et al: Clinical evaluation of flat-panel detector compared with multislice computed tomography in 65 patients with acute intracranial hemorrhage: initial results. Clinical article. J Neurosurg 2010;113:901-907.
Struffert T, Richter G, Engelhorn T, et al: Visualisation of intracerebral haemorrhage with flat-detector CT compared to multislice CT: results in 44 cases. Eur Radiol 2009;19:619-625.
Hunt WE, Hess RM: Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg 1968;28:14-20.
Grangeat P: Mathematical framework of cone beam 3D reconstruction via the first derivative of the radon transform; in Herman G, Louis A, Natterer F (eds): Mathematical Methods in Tomography. Berlin Heidelberg, Springer, 1991, vol 1497, pp 66-97.
Lee SW, Wang G: Grangeat-type helical half-scan computerized tomography algorithm for reconstruction of a short object. Med Phys 2004;31:4-16.
Norris JW, Buchan A, Cote R, et al: Canadian guidelines for intravenous thrombolytic treatment in acute stroke. A consensus statement of the Canadian stroke consortium. Can J Neurol Sci 1998;25:257-259.
Kalender WA: Der Einsatz von Flachbilddetektoren für die CT-Bildgebung. Radiologe 2003;43:379-387.
Gupta R, Cheung AC, Bartling SH, et al: Flat-panel volume CT: fundamental principles, technology, and applications. Radiographics 2008;28:2009-2022.
Loose R, Wucherer M, Brunner T: Visualization of 3D low contrast objects by CT cone-beam reconstruction of a rotational angiography with a dynamic solid body detector. RoFo 2005;S1:PO160.
Struffert T, Deuerling-Zheng Y, Engelhorn T, et al: Feasibility of cerebral blood volume mapping by flat panel detector CT in the angiography suite: first experience in patients with acute middle cerebral artery occlusions. AJNR Am J Neuroradiol 2012;33:618-625.
Struffert T, Deuerling-Zheng Y, Kloska S, et al: Dynamic angiography and perfusion imaging using flat detector CT in the angiography suite: a pilot study in patients with acute middle cerebral artery occlusions. AJNR Am J Neuroradiol 2015;36:1964-1970.
Yang P, Niu K, Wu Y, et al: Time-resolved C-arm computed tomographic angiography derived from computed tomographic perfusion acquisition: new capability for one-stop-shop acute ischemic stroke treatment in the angiosuite. Stroke 2015;46:3383-3389.
Niu K, Yang P, Wu Y, et al: C-arm conebeam CT perfusion imaging in the angiographic suite: a comparison with multidetector CT perfusion imaging. AJNR Am J Neuroradiol 2016;37:1303-1309.
Davis S, Donnan GA: Time is Penumbra: imaging, selection and outcome. The Johann jacob wepfer award 2014. Cerebrovasc Dis 2014;38:59-72.
Gory B, Riva R, Derex L, Nighoghossian N, Turjman F: Value of perfusion CT-guided recanalization therapy in acute ischemic stroke patients. Cerebrovasc Dis 2014;37:389-390.
Leng X, Fang H, Leung TW, et al: Impact of collateral status on successful revascularization in endovascular treatment: a systematic review and meta-analysis. Cerebrovasc Dis 2016;41:27-34.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.