"skipMainNavigation"
Search
Quick Search in Journals
Quick Search anywhere
Advanced Search
Radiology
Menu
Previous
Next
Original Research

Multiphase CT Angiography: A New Tool for the Imaging Triage of Patients with Acute Ischemic Stroke

Published Online:Jan 29 2015https://doi.org/10.1148/radiol.15142256

Abstract

We describe multiphase CT angiography, an imaging tool for clinical decision making in patients with acute ischemic stroke; in the current study, we demonstrate its reliability and ability to help predict clinical outcome.

Purpose

To describe the use of an imaging selection tool, multiphase computed tomographic (CT) angiography, in patients with acute ischemic stroke (AIS) and to demonstrate its interrater reliability and ability to help determine clinical outcome.

Materials and Methods

The local ethics board approved this study. Data are from the pilot phase of PRoveIT, a prospective observational study analyzing utility of multimodal imaging in the triage of patients with AIS. Patients underwent baseline unenhanced CT, single-phase CT angiography of the head and neck, multiphase CT angiography, and perfusion CT. Multiphase CT angiography generates time-resolved images of pial arteries. Pial arterial filling was scored on a six-point ordinal scale, and interrater reliability was tested. Clinical outcomes included a 50% or greater decrease in National Institutes of Health Stroke Scale (NIHSS) over 24 hours and 90-day modified Rankin Scale (mRS) score of 0–2. The ability to predict clinical outcomes was compared between single-phase CT angiography, multiphase CT angiography, and perfusion CT by using receiver operating curve analysis, Akaike information criterion (AIC), and Bayesian information criterion (BIC).

Results

A total of 147 patients were included. Interrater reliability for multiphase CT angiography is excellent (n = 30, κ = 0.81, P < .001). At receiver operating characteristic curve analysis, the ability to predict clinical outcome is modest (C statistic = 0.56, 95% confidence interval [CI]: 0.52, 0.63 for ≥50% decrease in NIHSS over 24 hours; C statistic = 0.6, 95% CI: 0.53, 0.68 for 90-day mRS score of 0–2) but better than that of models using single-phase CT angiography and perfusion CT (P < .05 overall). With AIC and BIC, models that use multiphase CT angiography are better than models that use single-phase CT angiography and perfusion CT for a decrease of 50% or more in NIHSS over 24 hours (AIC = 166, BIC = 171.7; values were lowest for multiphase CT angiography) and a 90-day mRS score of 0–2 (AIC = 132.1, BIC = 137.4; values were lowest for multiphase CT angiography).

Conclusion

Multiphase CT angiography is a reliable tool for imaging selection in patients with AIS.

© RSNA, 2015

Online supplemental material is available for this article.

References

  • 1. Menon BK, Demchuk AM. Is acute stroke treatment heading towards a more endovascular approach? Lancet Neurol 2009;8(9):778–779.
    Medline Google Scholar
  • 2. Saver JL, Jahan R, Levy EI, et al. Solitaire flow restoration device versus the Merci Retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial. Lancet 2012;380(9849):1241–1249.
    Medline Google Scholar
  • 3. Nogueira RG, Lutsep HL, Gupta R, et al. Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial. Lancet 2012;380(9849):1231–1240.
    Medline Google Scholar
  • 4. Menon BK, Hill MD, Eesa M, et al. Initial experience with the Penumbra Stroke System for recanalization of large vessel occlusions in acute ischemic stroke. Neuroradiology 2011;53(4):261–266.
    Medline Google Scholar
  • 5. Goyal M, Menon BK, Coutts SB, Hill MD, Demchuk AM; Penumbra Pivotal Stroke Trial Investigators, Calgary Stroke Program, and the Seaman MR Research Center. Effect of baseline CT scan appearance and time to recanalization on clinical outcomes in endovascular thrombectomy of acute ischemic strokes. Stroke 2011;42(1):93–97.
    Medline Google Scholar
  • 6. Menon BK, Goyal M. Endovascular therapy in acute ischemic stroke: where we are, the challenges we face and what the future holds. Expert Rev Cardiovasc Ther 2011;9(4):473–484.
    Medline Google Scholar
  • 7. Broderick JP, Schroth G. What the SWIFT and TREVO II trials tell us about the role of endovascular therapy for acute stroke. Stroke 2013;44(6):1761–1764.
    Medline Google Scholar
  • 8. Rha JH, Saver JL. The impact of recanalization on ischemic stroke outcome: a meta-analysis. Stroke 2007;38(3):967–973.
    Medline Google Scholar
  • 9. Menon BK, Almekhlafi MA, Pereira VM, et al. Optimal workflow and process-based performance measures for endovascular therapy in acute ischemic stroke: analysis of the Solitaire FR thrombectomy for acute revascularization study. Stroke 2014;45(7):2024–2029.
    Medline Google Scholar
  • 10. Gupta AC, Schaefer PW, Chaudhry ZA, et al. Interobserver reliability of baseline noncontrast CT Alberta Stroke Program Early CT Score for intra-arterial stroke treatment selection. AJNR Am J Neuroradiol 2012;33(6):1046–1049.
    Medline Google Scholar
  • 11. Wardlaw JM, Mielke O. Early signs of brain infarction at CT: observer reliability and outcome after thrombolytic treatment—systematic review. Radiology 2005;235(2):444–453.
    Google Scholar
  • 12. Patel SC, Levine SR, Tilley BC, et al. Lack of clinical significance of early ischemic changes on computed tomography in acute stroke. JAMA 2001;286(22):2830–2838.
    Medline Google Scholar
  • 13. Coutts SB, Hill MD, Demchuk AM, Barber PA, Pexman JH, Buchan AM. ASPECTS reading requires training and experience. Stroke 2003;34(10):e179; author reply e179.
    Medline Google Scholar
  • 14. Bal S, Bhatia R, Menon BK, et al. Time dependence of reliability of noncontrast computed tomography in comparison to computed tomography angiography source image in acute ischemic stroke. Int J Stroke 2015;10(1):55–60.
    Medline Google Scholar
  • 15. Menon BK, Smith EE, Modi J, et al. Regional leptomeningeal score on CT angiography predicts clinical and imaging outcomes in patients with acute anterior circulation occlusions. AJNR Am J Neuroradiol 2011;32(9):1640–1645.
    Medline Google Scholar
  • 16. Sheth KN, Terry JB, Nogueira RG, et al. Advanced modality imaging evaluation in acute ischemic stroke may lead to delayed endovascular reperfusion therapy without improvement in clinical outcomes. J Neurointerv Surg 2013;5(Suppl 1):i62–i65.
    Medline Google Scholar
  • 17. Goyal M, Menon BK, Derdeyn CP. Perfusion imaging in acute ischemic stroke: let us improve the science before changing clinical practice. Radiology 2013;266(1):16–21.
    Google Scholar
  • 18. Menon BK, O’Brien B, Bivard A, et al. Assessment of leptomeningeal collaterals using dynamic CT angiography in patients with acute ischemic stroke. J Cereb Blood Flow Metab 2013;33(3):365–371.
    Medline Google Scholar
  • 19. Frölich AM, Wolff SL, Psychogios MN, et al. Time-resolved assessment of collateral flow using 4D CT angiography in large-vessel occlusion stroke. Eur Radiol 2014;24(2):390–396.
    Medline Google Scholar
  • 20. 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.
    Medline Google Scholar
  • 21. Mnyusiwalla A, Aviv RI, Symons SP. Radiation dose from multidetector row CT imaging for acute stroke. Neuroradiology 2009;51(10):635–640.
    Medline Google Scholar
  • 22. Authors on behalf of ICRP, Stewart FA, Akleyev AV, et al. ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs—threshold doses for tissue reactions in a radiation protection context. Ann ICRP 2012;41(1-2):1–322.
    Google Scholar
  • 23. Adatia S, Menon BK, Sohn SI et al. A novel CT-angiogram based recanalization grading system (TICI-CTA) correlates with early neurologic response after intravenous tPA therapy. Stroke. 2013;44:AWP52.
    Google Scholar
  • 24. Campbell BC, Christensen S, Levi CR, et al. Cerebral blood flow is the optimal CT perfusion parameter for assessing infarct core. Stroke 2011;42(12):3435–3440.
    Medline Google Scholar
  • 25. Bivard A, Levi C, Spratt N, Parsons M. Perfusion CT in acute stroke: a comprehensive analysis of infarct and penumbra. Radiology 2013;267(2):543–550.
    Google Scholar
  • 26. Yoo AJ, Verduzco LA, Schaefer PW, Hirsch JA, Rabinov JD, González RG. MRI-based selection for intra-arterial stroke therapy: value of pretreatment diffusion-weighted imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization. Stroke 2009;40(6):2046–2054.
    Medline Google Scholar
  • 27. Lansberg MG, Straka M, Kemp S, et al. MRI profile and response to endovascular reperfusion after stroke (DEFUSE 2): a prospective cohort study. Lancet Neurol 2012;11(10):860–867.
    Medline Google Scholar
  • 28. Gönen M. Analyzing receiver operating characteristic curves using SAS. Cary, NC: SAS Press, 2007.
    Google Scholar
  • 29. Adams NM, Hand DJ. Improving the practice of classifier performance assessment. Neural Comput 2000;12(2):305–311.
    Medline Google Scholar
  • 30. Nagakane Y, Christensen S, Brekenfeld C, et al. EPITHET: positive result after reanalysis using baseline diffusion-weighted imaging/perfusion-weighted imaging co-registration. Stroke 2011;42(1):59–64.
    Medline Google Scholar
  • 31. Kudo K, Sasaki M, Yamada K, et al. Differences in CT perfusion maps generated by different commercial software: quantitative analysis by using identical source data of acute stroke patients. Radiology 2010;254(1):200–209.
    Google Scholar
  • 32. Zussman BM, Boghosian G, Gorniak RJ, et al. The relative effect of vendor variability in CT perfusion results: a method comparison study. AJR Am J Roentgenol 2011;197(2):468–473.
    Medline Google Scholar
  • 33. Lansberg MG, Lee J, Christensen S, et al. RAPID automated patient selection for reperfusion therapy: a pooled analysis of the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET) and the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) Study. Stroke 2011;42(6):1608–1614.
    Medline Google Scholar
  • 34. Hand PJ, Wardlaw JM, Rowat AM, Haisma JA, Lindley RI, Dennis MS. Magnetic resonance brain imaging in patients with acute stroke: feasibility and patient related difficulties. J Neurol Neurosurg Psychiatry 2005;76(11):1525–1527.
    Medline Google Scholar

Article History

Received September 22, 2014; revision requested October 22; revision received December 17; accepted December 19; final version accepted January 12, 2015.
Published online: Jan 29 2015
Published in print: May 2015