Technical Aspects o of Brain S SPECT J k Edwar Jack Ed rd d JJuni,i M M.D. D CardiA Arc, Inc. an nd William Beaumont Hospital Slides are not to be reproduced without permission of author. Patient Prreparation Place and secure venous access Semi-recumbent S i b t position p iti Eyes and ears ope en Allow 10-15 min before injecting After injecting allow w additional 10 min Slides are not to be reproduced without permission of author. Differences betw ween HMPAO and EC CD • Dosimetry / adm ministered dose • HMPAO - 20 mCi; ECD - 30 mCi • Delay before im maging • HMPAO - 90 min; ECD - 45 min • Uptake versus • Perfusion • Metabolism Slides are not to be reproduced without permission of author. ECD versuus HMPAO ECD vs HMPAO Greater dynamic range Higher relative uptake in: Cerebellum Basal ganglia Th l Thalamus Visual cortex Lower relative uptake in: Medial temporal lobes Frontal lobes Image from Asenbaum JNM M 1998; 39:613 Differences in trracer upt in temp lobbes HMPAO ECD Adapted from Oku: JNM 1997 38:1109 ECD Washout From Ichise M JNM 1997; 38:1253 Acquiisition • Use highest resolution n collimator available • Fan beams preferable p e • • • • Smallest possible radius of rotation (<13 cm) 128x128 128 128 matrix t i ((< 3 mm m pixels) i l ) 3 degrees g /p projection j n ((120 p projections) j ) Multiple sequential accquisitions Slides are not to be reproduced without permission of author. Patient motion • Blurs data (reduc ( ces resolution)) • Mixes data from different slices • Causes both hott and cold defects Slides are not to be reproduced without permission of author. Patientt motion Least motion More motion Severe motion Severe motion Image source: M. Devous, Ph.D. Patient Motion Only comfortable patients p hold still Position os t o for o co comfo o ortt Correct in softw ware Slides are not to be reproduced without permission of author. The Optim mum Filter Reduce imag ge noise... g but not blu ur undulyy Increase contrast… but not cause artifacts Slides are not to be reproduced without permission of author. Butterworth Fillter Parameters Cut off frrequency Cut-off Smooth Blurry Bl Sharp N i Noisy L Low Hi h High Ord der Less “ringing” artifact N i Noisy Crisp / High contrast “Ri i ” artifact “Ringing” tif t Slides are not to be reproduced without permission of author. Effect of fillter “order” order Order = 1 Order = 6 Order = 12 Butterworth ((low p pass)) filter Cut-off frequ uency = 0.22 Optimizing Filtter Parameters “Clorox bottle” phanttom 1) Acquire • Typical patien nt study • High-count ph hantom image 2) Alternate betwe een image sets • Patient scan • Adjust cut-o off (sharpness) • Phantom scan n • Adjust orde er (contrast) Slides are not to be reproduced without permission of author. “Resolution Recovery” y Filters Butterworth (low pass) Weiner Metz “Ultra-Metz” Attenuation n Correction Ready for atten corr - bkg shows Attenuation n Correction Ready for atten corr - bkg shows Attenuation n Correction Ready for atten corr - bkg shows Ready for atten corr - bkg shows Ready for atten corr - bkg shows Ready for atten corr - bkg shows Ready for atten corr - bkg shows Variations in Ellipse Fitting Source: D Pavel, MD UIC Variations in Ellipse Fitting Source: D Pavel, MD UIC Cadaver transsaxial slices #2 http://members.home.n net/jjuni/public/vhum.jpg Imaging Vasc cular Reserve Acetazolamiide (Diamox) Normal va asculature rCBF 50 - 80% Tracer uptake Vascular insufficiency rCBF Tracer uptake (already maximally dilated)) Slides are not to be reproduced without permission of author. Diamo ox - RC Base eline RC Diam mox Diamo ox - RC Base eline RC Slice Reo orientation Slice ori ientation Slice Reo orientation Slice ori ientation Slice Reo rientation Slice oriientation Temporal lob be “long-axis” Changes in Perfu usion with Aging O-15 H20 PET Slides are not to be reproduced without permission of author. Case: Professor H - gray on white Keys y to High g Q Quaalityy Brain SPECT • Proper p p preparation p of tracer - fresh eluate • Consistent, non-stimulating environment • Keep the patient com mfortable. • Optimized filter param meters • Either pre-filter or 3-D D post-filter • Consistent slice orien ntation • Appreciation A i ti off norm mall variability i bilit & aging i Slides are not to be reproduced without permission of author. Thankk you! Tracers Filters Order Cross sections Normal aging Temp long-axis Anatomic correlation White matter Slides are not to be reproduced without permission of author. Acute Slides are not to be reproduced without permission of author. Atrophyy HO b/w Slides are not to be reproduced without permission of author. Atrophyy HO b/w Slides are not to be reproduced without permission of author. Atrophy HO-- SPECT_CT compposite Slides are not to be reproduced without permission of author. Normal Transverse Brain B SPECT Images Transaxial obblique sections Image source: Mich hael Devous, Sr Ph.D. Sr., Ph D Normal Sagittal Brrain SPECT Images Normal Saggittal SPECT Image source: Mich hael Devous, Sr Ph.D. Sr., Ph D Ant Post Normal Coronal Brrain SPECT Images Normal Corronal SPECT Image source: Mich hael Devous, Sr Ph.D. Sr., Ph D Right g Left Special Temporal Lobe Oblique Views Normal Temp poral lobe cuts Image source: Mich hael Devous, Sr Ph.D. Sr., Ph D Right g Left Differentiation between transient ischemic attacks and f six hours after onset of ischemic stroke within the first symptoms by using 99mTc-ECD-SPECT 9 Berrouschot J, et al: J Cereb Bloood Flow & Metab 1998; 18:921 Prospective study SPECT within 6 hrs: Outcome: Acute MCA ischemia 82 pts Perfusion < 70% 59 pts Perfusion >70% 23 pts Infarct at a dayy 7 59 pts No infarct at day y7 23 pts Slides are not to be reproduced without permission of author. Acute Stroke an nd Thrombolysis 1.00 Recovery withou ut treatment relattive rCB BF 0.75 Salvage w tx 0.50 0.25 Infarct 0.00 0 3 tim me (hours) 6 Slides are not to be reproduced without permission of author. Outcome vs. Sev verity of Ischemia 1 Non-infarction Infarction Hemorrhage R/CE rratio 0.9 0.8 0.7 06 0.6 0.5 0.4 0.3 0.2 0.1 0 1 1.1 1 1 1.2 1 2 1.3 1 3 1.4 1 4 1.5 1 5 1.6 1 6 1.7 1 7 1.8 1 8 1.9 19 2 Asymmetry in ndex Toshihiro T hihi U Ueda, d MD Dept. of Neurosurgery Ehime University, JAPAN J Cereb Blood Flow Metab 1999;19:99-108 Slides are not to be reproduced without permission of author. Case: 61 M, 3 hours Pretreatment SPECT Follow-up CT R/CE ratio = 0 0.12 12 Asymmetry index = 1.71 Ueda et al; JCBFM 1999;19:99-108 Slides are not to be reproduced without permission of author. Outcome vs. Severrity and Duration of Ische emia 1 Non-infarction Infarction Hemorrhage 09 0.9 R/C CE rattio 0.8 0.7 0.6 0.55 0.5 0.4 0.35 0.3 02 0.2 0.1 0 0 2 4 6 8 Interval (hrs) 1 10 12 Adapted from Ueda T, T et al: Outcome in acute stroke with successful intra-arterial thrombolysis and predictive value of initial singlephoton emission-computed emission computed tomography. J Cereb Blood Flow Metab 1999;19:99-108 Slides are not to be reproduced without permission of author. Why do smalll white-matter l i lesions cause large l deficits? d fi i ? Slides are not to be reproduced without permission of author. Axona Axonall Injury Slides are not to be reproduced without permission of author. White mattter infarcts MR vs SPECT Slides are not to be reproduced without permission of author. Temporaal al lobe trauma AT2612988 Where do thin ngs go wrong? Patient motion Timing of im mages Filtering Attenuation n correction Slice summ mation N Normal l varriability i bilit Slides are not to be reproduced without permission of author. Radiotraccer Uptake •Radiotracer injected in nto bloodstream •Passes through BBB (lipophilic) •Extracted and retained byy brain tissue Amount retained A i d by b b brain i tissue i iis proportional to tissue perfusion perfusion. Slides are not to be reproduced without permission of author. Rivers - Jungle & Desert Images licensed fro om and copyrighted by Ph hotosToGo Mismatch of Larrge vessel flow to tissue levell perfusion Microvascular disease • Hypertension • Diabetes • Vasculitis Metabolic changes • • • • • • • Activation and de-activation Alzheimer’s disease Seizures ((ictal and interictal)) Diaschisis, axonal disruption Brain trauma Edema Infection Slides are not to be reproduced without permission of author. Coupling of Regiona al Cerebral Perfusion with Regiona al Metabolism 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 5 10 CMRO2(um mol/gm/min) From Nilsson et al, Ciba Found Symp 1978; 56:19 99 Slides are not to be reproduced without permission of author.