INTRODUCTION TO NEURO MR Dr Francis Neuffer USC School of Medicine Department of Radiology MR IMAGING • Based on behavior of protons exposed to a magnetic field and a radio wave • T1, T2, FLAIR, Diffusion, Gadolinium enhanced, and Angiography are specific types of Neuro imaging sequences RF MR INTERPRETATION • Symmetry • Identify normal structures – Ventricles – Grey matter structures – White matter tracts – Language – Intensity/ Signal – Description of tissue signal on various different scanning sequences ie – T1 T2 Flair Diffusion Gadolinium MAGNETIC RESONANCE IMAGING Limitations ICU patients and Claustrophobia Metal artifact RF Energy – pacemaker override Magnetic field - aneurysm clips - ocular metal -missile effect Nephrogenic Systemic Fibrosisgadolinium toxicity in renal failure Child Dies in MRI Machine The Associated Press Monday, July 30, 2001: 2:42 p.m EDT A child undergoing an MRI exam received a fatal head wound when the machine’s powerful magnet pulled a metal oxygen canister inside GADOLINEUM TOXICITY MAGNETIC RESONANCE IMAGING Advantages Multiple signal sources No iodine toxicity/allergy issues No ionizing radiation issues VASCULAR ANATOMY ACA MCA ACoA ICA PCA Basilar Artery Circle of Willis PCoA VASCULAR DISTRIBUTIONS ACA MCA PCA STROKE • Ischemic – Large artery atherosclerosis • Higher mortality – Cardioembolism • Recurrence – Small vessel ischemia • Occlusion of small end arteries • Predilection for BG, IC, Pons, Corona Radiata • Hemorrhagic IMAGING OF STROKE • CT – Better identification of acute hemorrhage – Availability – Decrease expense – Decrease time – Less contraindications • MRI – More sensitive to early changes of stroke ie edema CT FINDINGS SAH STROKE INTERVENTION • THROMBOLYTIC THERAPY TO SALVAGE ISCHEMIC BRAIN AT THE BORDER OF THE INFARCT ZONE • WHO BENEFITS AND HOW SELECT? STROKE INTERVENTION • • • • TIME CONSTRAINTS 3-6 HOUR WINDOW RISK OF HEMORRAGIC CONVERSION WITH THROMBOLYTIC THERAPY RT LT MR PERFUSION Gadolineum Injection CT PERFUSION Iodine Injection GOAL FOR IMAGING COMPARISON OF INFARCT ZONE AND ISCHEMIC ZONE TO IDENTIFY TREATMENT CANDIDATES MRI FINDINGS OF ACUTE STROKE T1 (hypointense) FLAIR (hyperintense) T2 (hyperintense) Diffusion (hyperintense) ... RING LESION NON ENHANCED T1- SCAN – WITHOUT GADOLINEUM T1 – SCAN WITH GADOLINEUM T2- SCAN MR NORMAL PITUITARY ADENOMA ABNORMAL T1 SAGITTAL MR WITHOUT GADOLINEUM WITH GADOLINEUM ACOUSTIC NEUROMA WITHOUT... No iodine toxicity/allergy issues No ionizing radiation issues MR HAS ADVANTAGE OF MULTI PLANAR IMAGING MRI INDICATIONS • • • • • Ischemia Tumor Infection Dating blood products Congenital abnormalities... Diffusion, Gadolinium enhanced, and Angiography are specific types of Neuro imaging sequences RF MR INTERPRETATION • Symmetry • Identify normal structures – Ventricles – Grey matter structures – White