The Role of Neuroimaging in Acute Stroke Bradley Molyneaux, HMS IV
Patient CR 62 yo F w/ 2 wk h/o altered mental status Presents to ED w/ confusion following a fall 1 day prior New onset left facial droop while in ED
Acute Stroke Critical questions for neuroimaging Rule out stroke mimics: tumor, encephalitis, subdural, epidural, SAH Is there ICH? What is infarcted vs. tissue at risk? Underlying pathogenesis
Imaging determines treatment If ICH present: no thrombolytics, control hypertension If no ICH - consider thrombolytics: < 3 hours: IV rtpa < 6 hours: IA urokinase < 24 hours & in posterior cirulation: IV rtpa < 6 Hours: IR clot retrieval
The 1 st step - Noncontrast CT Sensitive for rtpa contraindications Intraparenchymal hemorrhage Subarachnoid hemorrhage Stroke mimics CT signs of ischemic stroke Hyperdense MCA sign Loss of gray-white differentiation Loss of insular ribbon Cortical sulcal effacement Focal parenchymal hypoattenuation
Noncontrast CT of Patient CR...
Patient CR BIDMC radiology
Patient CR BIDMC radiology
Patient CR BIDMC radiology
Patient CR BIDMC radiology
Patient CR BIDMC radiology
Companion Patient #1: Intracerebral hemorrhage and midline shift Image courtesy MGH radiology
CT signs of ischemic stroke Hyperdense MCA sign Loss of gray-white differentiation Loss of insular ribbon Cortical sulcal effacement Focal parenchymal hypoattenuation
Middle cerebral artery (arrow) Netter, Netter Collection of Med. Illust.
Companion Patient #2: Hyperdense MCA & Sulcal Effacement Vaibhav Khasigiwala, BIDMC
MRI in stroke FLAIR - T2 signal with black CSF DWI - image areas of slow diffusion, earliest sign of infarction ADC - eliminates T2 shine-through of DWI PWI - perfusion weighted imaging MRA - image vessel occlusions
Patient CR : MRI reveals infarcts at different stages...
Patient CR : MRI reveals infarcts at different stages FLAIR DWI ADC Patient CR BIDMC radiology
Patient CR : MRI reveals infarcts at different stages FLAIR DWI ADC Patient CR BIDMC radiology
Patient CR : MRA - occlusion in right MCA Courtesy BIDMC radiology Courtesy BIDMC radiology
MCA embolus blocking lenticulostriate artery origin www.meddean.luc.edu
Summary & Future Directions CT is 1 st step in imaging for acute stroke Initial studies suggest MRI is equally effective in detecting ICH, but it is less available & less widely accepted More criteria needed for selecting pts for rtpa DWI vs. PWI might aid in selecting patients for thrombolysis in the future
References Adams H, Adams R, Del Zoppo G, Goldstein LB (2005) Guidelines for the early management of patients with ischemic stroke: 2005 guidelines update a scientific statement from the Stroke Council of the American Heart Association/American Stroke Association. Stroke 36:916-923. Beauchamp NJ, Jr., Barker PB, Wang PY, vanzijl PC (1999) Imaging of acute cerebral ischemia. Radiology 212:307-324. Fiebach JB, Schellinger PD, Gass A, Kucinski T, Siebler M, Villringer A, Olkers P, Hirsch JG, Heiland S, Wilde P, Jansen O, Rother J, Hacke W, Sartor K (2004) Stroke magnetic resonance imaging is accurate in hyperacute intracerebral hemorrhage: a multicenter study on the validity of stroke imaging. Stroke 35:502-506. Mullins ME (2006) Modern emergent stroke imaging: pearls, protocols, and pitfalls. Radiol Clin North Am 44:41-62, vii-viii. Schlaug G, Siewert B, Benfield A, Edelman RR, Warach S (1997) Time course of the apparent diffusion coefficient (ADC) abnormality in human stroke. Neurology 49:113-119. Somford DM, Nederkoorn PJ, Rutgers DR, Kappelle LJ, Mali WP, van der Grond J (2002) Proximal and distal hyperattenuating middle cerebral artery signs at CT: different prognostic implications. Radiology 223:667-671.
Acknowledgements Vaibhav Khasgiwala, MD Pamela Lepkowski Larry Barbaras