3 Medical Imaging for Acute Ischemic and Hemorrhagic Stroke

Andrew Pines, Austin Pena, and Brian W. Chong

Abstract

This chapter will provide the reader with an overview of the current guidelines on how to best employ medical imaging modalities in acute stroke care. We will include supporting images, clinical pearls, and tables to compare imaging modalities side by side. We will also summarize the latest research considering current and future applications. First, we will review the use of noncontrast head computed tomography (CT), and important signs to look for in both hemorrhagic and ischemic stroke patients. We will introduce the Alberta Stroke Program Early CT Score (ASPECTS) score and its relevance to evaluating the patient with acute ischemic stroke. We will then discuss the utility of CT angiography and CT perfusion studies. We will review the recent studies that have used novel CT perfusion algorithms to extend the window for endovascular thrombectomy procedures in patients with larger vessel occlusions. Acute stroke evaluation with magnetic resonance imaging will be discussed along with a review of how different institutions employ this technique in the acute stroke setting. The merits and detriments of diffusion-weighted imaging and perfusion-weighted imaging will be contrasted. In the final section of the chapter, we will explain the evidence supporting the use of magnetic resonance angiography in specific scenarios. This chapter will outline the utility of CT and MR imaging in determining treatment in the acute period of stroke management. We will cover the key components of current guidelines in order to provider the reader with a succinct summary of both established practice and the latest research.

Key words

noncontrast head CT - CTA - CTP - ASPECTS - MRA - acute hemorrhagic stroke - acute ischemic stroke

• 1 Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 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 2018; 49 (3) e46-e110 PubMed

• 2 Kothari RU, Brott T, Broderick JP et al. The ABCs of measuring intracerebral hemorrhage volumes.. Stroke 1996; 27 (8) 1304-1305 PubMed

• 3 Aguilar MI, Brott TG. Update in intracerebral hemorrhage.. Neurohospitalist 2011; 1 (3) 148-159 PubMed

• 4 Romero JM, Brouwers HB, Lu J et al. Prospective validation of the computed tomographic angiography spot sign score for intracerebral hemorrhage.. Stroke 2013; 44 (11) 3097-3102 PubMed

• 5 Khan Z, Nattanmai P, George P, Newey CR. Spot sign in acute intracerebral hemorrhage in magnetic resonance imaging: a case report and review of the literature.. Neurologist 2018; 23 (3) 104-107 PubMed

• 6 Selariu E, Zia E, Brizzi M, Abul-Kasim K. Swirl sign in intracerebral haemorrhage: definition, prevalence, reliability and prognostic value.. BMC Neurol 2012; 12: 109 PubMed

• 7 Barber PA, Demchuk AM, Zhang J, Buchan AM. Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy. ASPECTS Study Group. Alberta Stroke Programme Early CT Score.. Lancet 2000; 355 (9216) 1670-1674 PubMed

• 8 Hill MD, Demchuk AM, Tomsick TA, Palesch YY, Broderick JP. Using the baseline CT scan to select acute stroke patients for IV-IA therapy.. AJNR Am J Neuroradiol 2006; 27 (8) 1612-1616 PubMed

• 9 Dzialowski I, Hill MD, Coutts SB et al. Extent of early ischemic changes on computed tomography (CT) before thrombolysis: prognostic value of the Alberta Stroke Program Early CT Score in ECASS II.. Stroke 2006; 37 (4) 973-978 PubMed

• 10 Tsivgoulis G, Saqqur M, Sharma VK, Lao AY, Hoover SL, Alexandrov AV, . Association of pretreatment ASPECTS scores with tPA-induced arterial recanalization in acute middle cerebral artery occlusion.. J Neuroimaging 2008; 18 (1) 56-61 PubMed

• 11 Berkhemer OA, Fransen PSS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke.. N Engl J Med 2015; 372 (1) 11-20 PubMed

• 12 Camargo ECS, Furie KL, Singhal AB et al. Acute brain infarct: detection and delineation with CT angiographic source images versus nonenhanced CT scans.. Radiology 2007; 244 (2) 541-548 PubMed

• 13 Menon BK, Demchuk AM. Computed tomography angiography in the assessment of patients with stroke/TIA.. Neurohospitalist 2011; 1 (4) 187-199 PubMed

• 14 Lima FO, Lev MH, Levy RA et al. Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathy.. AJNR Am J Neuroradiol 2010; 31 (5) 817-821 PubMed

• 15 Hopyan J, Ciarallo A, Dowlatshahi D et al. Certainty of stroke diagnosis: incremental benefit with CT perfusion over noncontrast CT and CT angiography.. Radiology 2010; 255 (1) 142-153 PubMed

• 16 Allmendinger AM, Tang ER, Lui YW, Spektor V. Imaging of stroke: part 1, perfusion CT—overview of imaging technique, interpretation pearls, and common pitfalls.. AJR Am J Roentgenol 2012; 198 (1) 52-62 PubMed

• 17 Shen J, Li X, Li Y, Wu B. Comparative accuracy of CT perfusion in diagnosing acute ischemic stroke: a systematic review of 27 trials.. PLoS One 2017; 12 (5) e0176622 PubMed

• 18 Simonsen CZ, Madsen MH, Schmitz ML, Mikkelsen IK, Fisher M, Andersen G. Sensitivity of diffusion- and perfusion-weighted imaging for diagnosing acute ischemic stroke is 97.5%.. Stroke 2015; 46 (1) 98-101 PubMed

• 19 Parsons MW, Pepper EM, Chan V et al. Perfusion computed tomography: prediction of final infarct extent and stroke outcome.. Ann Neurol 2005; 58 (5) 672-679 PubMed

• 20 Nogueira RG, Jadhav AP, Haussen DC, et al. Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct.. N Engl J Med 2018; 378 (1) 11-21 PubMed

• 21 Albers GW, Marks MP, Kemp S, et al. Thrombectomy for stroke at 6 to 16 hours with selection by perfusion imaging.. N Engl J Med 2018; 378 (8) 708-718 PubMed

• 22 Shah S, Luby M, Poole K et al. Screening with MRI for accurate and rapid stroke treatment: SMART.. Neurology 2015; 84 (24) 2438-2444 PubMed

• 23 Chalela JA, Kidwell CS, Nentwich LM et al. Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison.. Lancet 2007; 369 (9558) 293-298 PubMed

• 24 Saver JL. Time is brain: quantified.. Stroke 2006; 37 (1) 263-266 PubMed

• 25 Schellinger PD, Bryan RN, Caplan LR, et al. Evidence-based guideline: The role of diffusion and perfusion MRI for the diagnosis of acute ischemic stroke: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.. Neurology 2010; 75 (2) 177-185 PubMed

• 26 Brunser AM, Hoppe A, Illanes S et al. Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct.. Stroke 2013; 44 (4) 1169-1171 PubMed

• 27 Latchaw RE, Alberts MJ, Lev MH, et al. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association.. Stroke 2009; 40 (11) 3646-3678 PubMed

• 28 Birenbaum D, Bancroft LW, Felsberg GJ. Imaging in acute stroke.. West J Emerg Med 2011; 12 (1) 67-76 PubMed

• 29 Breuer L, Schellinger PD, Huttner HB et al. Feasibility and safety of magnetic resonance imaging-based thrombolysis in patients with stroke on awakening: initial single-centre experience.. Int J Stroke 2010; 5 (2) 68-73 PubMed

• 30 Lansberg MG, Straka M, Kemp S et al. Magnetic resonance imaging profile and response to endovascular reperfusion: results of the DEFUSE 2 prospective cohort study.. Lancet Neurol 2012; 11 (10) 860-867