Brain stroke: CT or MRI?

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Nathaniel Fleming
7 years ago
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1 Brain stroke: CT or MRI? Pr Alexandre Krainik Department of Neuroradiology University Hospital of Grenoble - France

2 Stroke? Imaging Challenges To treat? Parenchyma ICH / stroke mimics To treat > 3 hr? Perfusion Penumbra To guide treatment? Vessels Thrombosis, stenosis

3 Parenchyma IntraCranial Hemorrhage Acute ICH NECT = MRI Subacute or chronic hem. MRI > CT No impact (< 5 µbleeds) NECT T2* NECT T2* Fiebach JB et al. Stroke 2004;35:502-6

4 Parenchyma Ischemic Tissue 42 yo woman. Right hemiplegia since 4 hr NECT Loss of gray-white differentiation Cortex Basal ganglia Swelling of gyri Sulcal effacement Ventricular compression Se. < 33 % for < 3 hr Se. < 66 % for < 6 hr

5 Parenchyma Ischemic Tissue 80 yo man. Right hemiplegia since 1 hr MRI DWI: hyperintensity + low ADC T2 FLAIR: normal < 3h / hyper > 3 Se % for < 6h

6 Parenchyma Ischemic Tissue 60 yo woman. Amnesia since 6 hr

7 Parenchyma Ischemic Tissue 60 yo woman. Aphasia since 3 hr 3T B1000 B3000

8 Parenchyma Ischemic Tissue 73 yo man. Left hand paresia since 4 hr MRI DWI Sensitivity and specificity > 90% for detecting infarct core Latchaw et al. Stroke 2009;40: Excellent intra and inter-observer reproducibility Fiebach et al. Stroke, 2002;33: MR Diffusion is the gold standard for detecting acute infarction < 3h Limitations of CT: posterior fossa, small infarcts (cortical and lacunar) Schaefer PW et al. Stroke 2008;39: , Kunst el al. Radiol Clin N Am 2011;49:1-26

9 Parenchyma Stroke Mimics 22 yo man. Dizziness, diplopia since 4 hr 5 years earlier: transient motor deficit MS Chalela JA et al. Lancet 2007;369:293-8

10 Imaging Challenges Parenchyma Parenchyma MRI > CT Perfusion ICH: CT = MR *Ischemia: MR Mimics: MR Vessels Small size Posterior fossa

11 Perfusion MISMATCH Necrosis CBV CBF MTT Penumbra CBV CBF MTT CBF CBV MTT to treat beyond 3 hr Compensatory mechanisms Autoregulation Vasoreactivity Distinguish between Core: irreversible risk ICH Penumbra: salvageable In clinical practice Perfusion imaging relies on DSC pmri pct Donnan GA et al. Lancet Neurol 2009;8:261-9

12 Perfusion MISMATCH MR Necrosis: DWI Penumbra: MTT - T0 CT Necrosis: CBV < 2ml/100g Penumbra: MTT > 145% Necrosis Penumbra Necrosis Penumbra Wintermark M at al. Stroke 2006;37: , Schaefer PW et al.stroke 2008;39:2986,92

13 Perfusion Pitfalls and limits DSC Hemorrhage Bolus Movements Quantification AIF VOF Thresholds Small infarct pct: Radiation exposure 80 kev, 120 mas 2-3 msv (NECT) for max 12 msv Imanishi et al. Eur Radiol 2005;15:41-6

14 Perfusion MR ASL 64 yo woman. Left hemiplegia since 2 hr ADC ASL STAR Pros No contrast media needed CBF quantification Cons Poor SNR (3T) Evolving technique Sensitive to blood speed Courtesy Dr JC Ferre Deibler AR et al. AJNR 2008;29:

15 Perfusion Functional disorder Right MCA stenosis Transient left hemiparesia DSC CBV DSC CBF BOLD CO 2 Impaired vascular reserve Zyieh Stroke 2005; Haller Radiology 2008

16 Imaging Challenges Perfusion Parenchyma MRI > CT Perfusion pct = pmri Penumbra: CT = MR Functional: MRI Vessels

17 Vessels Locate thrombosis NECT: white clot T2*: dark clot

18 Vessels Locate thrombosis CTA MRA Sensitivity and specificity of CTA > 90% for detecting proximal vessel occlusion CTA is more accurate method to evaluate distal vessels and collateral circulation MRA sensitivity increases using 3T, CE-TOF but speficity decreases Lev MH et al. J Comput Assist Tomogr 2001;25:520-8 Nguyen-Huynh el al. Stroke 2008;39:1184-8

19 Vessels Locate stenosis Dissection CTA CE-MRA NECT T1 SPIR Atherosclerosis CTA T2

20 Imaging Challenges Vessels Parenchyma MRI > CT Perfusion pct = pmri Thrombosis: CTA>MRA Stenosis: CTA>MRA Vessels CTA > MRA

21 Stroke Therapeutic Challenges Imaging Answers To treat < 3 hr? Parenchyma MRI > CT To treat > 3 hr? Perfusion pct = pmri Availibility Experience To guide treatment? Vessels CTA > MRA

22 Acknowledgments Pr Xavier LECLERC CHRU Lille France Dr Virginie LEFOURNIER CHU Grenoble France Dr Sylvie Grand CHU Grenoble France Dr Jean-Christophe FERRE CHU Rennes France Stroke 2009; 40:

23 Perfusion Functional disorder Right MCA stenosis Transient left hemiparesia BOLD CO 2 Impaired vascular reserve papg030211

24 Perfusion Functional disorder Basillar artery stenosis Dizziness BOLD CO 2 Preserved vascular reserve bilg240311

Imaging of Acute Stroke. Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group

Imaging of Acute Stroke. Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group Imaging of Acute Stroke Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group Modalities Non Contrast CT (NCCT) Contrast CT Angiography MRI MR Angiography Perfusion