CT and MRI in dementia: The new and the old

Transcription

1 CT and MRI in dementia: The new and the old Prof. Elna-Marie Larsson, MD, PhD Section of Neuroradiology, Department of Radiology Uppsala University, Akademiska sjukhuset Uppsala, Sweden DSKFNM 2015, Copenhagen Normal aging vs dementia Morphology: atrophy, ischemia, infarcts Physiology: Diffusion MRI incl DTI, perfusion-mri, (MRS, fmri), PET/MRI 1

2 NORMAL AGING VS DEMENTIA Ventricles and sulci, 61 healthy individuals, years Övre gräns för Grad 1 Grad 2 Grad 3 Grad 4 Ventricles years Sulci years Salonen, Neuroradiology

3 Normal aging - dementia Gradual transition with overlap Old individual may have widening of sulci and ventricles. Fast progression of parenchymal reduction supports diagnosis neurodegenerative dementia disorder Young individual (<40-60 years) should not have widening of sulci and ventricles Dementia classification Neurodegenerative dementia: e.g. Alzheimer s disese (AD) 50%, Lewy body dementia 15-20%, frontotemporal dementia (FTD) 15% Vascular dementia 10% Secondary dementia 5-10% e.g. normal pressure hydrocephalus (NPH), brain tumour 3

4 Suspected dementia: What do we need in the clinics and for research? Early diagnosis Evaluation of treatment response Radiology in the evaluation of dementia CT or MRI can Exclude surgical lesions (tumour, NPH, chronic SDH) Detect infarction/extensive ischemia (vascular dementia) Support clinical suspicion of degenerative dementia, differentiate between different types MRI > CT, but CT is very useful as basic exam 4

5 Clinical suspicion of AD: Imaging biomarkers play an increasing role Standardized terminology New lexicon for the definition of Alzheimer s disease (AD) (Dubois et al 2010): Clinical diagnosis: - Preclinical AD (asymptomatic at risk with CSF or imaging amyloid biomarkers, presymptomatic with mutations) - Prodromal AD ( pre-dementia ) AD with CSF or imaging (FDG or amyloid PET, MTA on MRI) biomarkers - AD (dementia) Neuropathological diagnosis: AD pathology (microscopic tissue diagnosis) Small et al, Lancet, Neurology,

6 MORPHOLOGY Morphology 1. Sulci and ventricles 2. Medial temporal lobe atrophy: MTA scoring (Scheltens scale) 3. White matter ischemia, infarcts 4. Lesions: tumor, normal pressure hydrocephalus, posttraumatic changes 6

7 Demens CT / MR utlåtande. Läkartidningen 47/2013 Global cortikal atrophy (GCA) GCA 0 1 GCA 2 3 (bifrontally) Wahlund et al, Läkartidningen 47/2013 7

8 Cortical thickness Difference between a group of AD-patients and a group of healthy controls (light blue is most severe). Simmons et al 2009 Hippocampus Normal Alzheimer s disease E-M Larsson 8

9 Duara, Neurology 2008 Red = hippocampus Blue = entorhinal cortex Green = perirhinal cortex Right medial temporal lobe Hippocampus is blue Visual scoring of medial temporal lobe atrophy (MTA) Scheltens et al. J Neurol 1995;242:558 9

10 Coronal''slice'through'the'le0'medial'temporal'lobe' 10

11 Medial temporal lobe atrophy visual scoring Age (years) MTA <70 (75) Normal Normal Normal Normal Normal >80 Normal Normal Normal Normal Adapted from Cavallin et al, Acta Radiol 2012 Medial temporal lobe atrophy Grade The temporal horns are usually not dilated in normal aging Wattjes et al, Radiology

12 2009 FTD FT Visual scoring of medial temporal lobe atrophy vs hippocampal volumetry 12

13 CT 75-year-old woman with Alzheimer s disease CT Three subtypes of AD automatic analysis of grey matter volume loss (Whitwell et al, Lancet Neurology 2012) 13

14 White matter hyperintensities Minimal moderate extensive Fazekas Wattjes et al, Radiology 2009 Vascular dementia T1 T2 FLAIR 14

15 87-year-old woman with NPH Thesis Johan Virhammar

16 Thesis Thesis Johan Johan Virhammar Virhammar 2014 NPH Clinical triad CT without contrast agent: morphology, transependymal fluid transsudation MRI : as CT + exclude aqueduct stenosis or tumour, detect hyperdynamic flow through the aqueduct CSF tap test and/or lumbar infusion test 16

17 Radiologial findings in NPH Dilated ventricles (Evans index>0.3) including temporal horns Effaced parietal sulci parasagittally and on high convexities Often wide Sylvian fissures, focal dilatation of sulci, often periventricular transudation of fluid Increased flow velocity through the aqueduct ( flow-void on MR), not pathognomonic (Decreased cerebral blood flow and cerebral blood volume) AJNR Dec 2014 NPH 17

18 J Neurosurg 2014 PHYSIOLOGY: MRI, PET/MRI 18

19 Physiological MRI in dementia Diffusion- MRI incl. DTI Perfusion-MR (MRS) (fmri) PET/MRI Diffusion MRI Diffusion weighted imaging (DWI): 3 directions Diffusion tensor imaging (DTI): at least 6 directions. Reconstruction: tractography Diffusion kurtosis imaging (DKI): several b-values, 15 directions 19

20 DTI tractography Corpus callosum (streamlines) DTI tractography ROI left cingulum 20

21 DTI tractography Track left cingulum Oblique view Straight lateral views MD in Healthy control mild AD Fischer, JMRI

22 Santillo et al 2013 Perfusion MRI Dementia with progressive aphasia DSC perfusion: rcbf MRI 22

23 FTD primary progressive aphasia CT FDG PET Pseudo continuous arterial spin labeling perfusion MRI (pcasl) Imaging Volume Labeling volume Perfusion method ideal for repeated measurements No contrast agent No ionizing radiation Short scan time (5 min) 23

24 MRM 2014 Alsop et al

25 Wang et al 2013 Direct comparison of FDG-PET and ASL MRI in AD Musiek,

26 Cognitive reserve Stern, Lancet Neurology 2012 Biomarkers of early AD (Neuroimaging and CSF) Measures of neurodegeneration (MRI: grey matter volume loss, diffusion and perfusion changes FDG-PET: decreased glucose metabolism) Amyloid-beta deposition in the brain (PET) PET/MRI 26

27 Ann Neurol 2004;55: Healty control AD Jack et al

28 sequential is now simultaneous. Courtesy of Siemens Sweden s first PET/MRI scanner 3T GE Uppsala

29 Dementia work-up in clinical radiology CT of the brain is very helpful MRI is better and should always be done in young patients (< 65 years) FDG-PET is an excellent method PET-CT provides combined information Dementia research MRI with morphological and physiological techniques PET PET/MRI 29

30 Thank you Scandinavian network for standardization of MRI and CT in dementia and for potential research collaboration. 2-3 meetings/year in Scandinavia. Contact person: Eric Westman, Karolinska Institute, Stockholm 30

31 ISMRM Nordic Chapter & DSMMR joint MR meeting - MRI from head-to-toe Topics: The expanding role of MRI in radiation therapy, Multiple Sclerosis and Cardiac MRI or 31