MRI of Cartilage. D. BENDAHAN (PhD)

Transcription

1 MRI of Cartilage D. BENDAHAN (PhD) Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 7339 Faculté de Médecine de la Timone 27, Bd J. Moulin Marseille France

2 CNRS Research Unit 7339 (CRMBM / CEMEREM) 3 T 1.5 T

3 MRI of Cartilage Inflammatory Rheumatisms Diagnosis «Outcome Measures» Mechanical Rheumatisms Therapeutic follow-up

4 MRI investigations of joints Bone erosions Synovitis Bone edema Cartilage?

5 Current MRI investigations of cartilage in Rheumatoid Arthritis

6 Current MRI quantitative investigations of cartilage in Rheumatoid Arthritis N = 15 patients vs 4 controls 5 readers 1 reader twice

7

8 MRI investigations of joints Score related to the JSN what else. More functional / quantitative information?

9 Cartilage Matrix Collagen 20% Structural basis Neutral Proteoglycans 5% Negatively charged T1 mapping (Gd) T2 mapping Na +

10 Biochemical investigation of cartilage using MRI Normal Partial depletion Total depletion

11 delayed Gadolinium-Enhanced MRI of Cartilage Gd(DTPA) 2- Map T1 T1 Map [GAG] Map

12 delayed Gadolinium-Enhanced MRI of Cartilage Proton density MRI T1-W MRI T1 Map Histological coloration

13 delayed Gadolinium-Enhanced MRI of Cartilage From a practical point of view MRI PreC Gd injection Exercise (20m) Rest(60m) MRI Post-C duration : 3 to 15 min according to the pulse sequnce used Résolution: 0.4 mm * 0.4 mm Slice thickness : 3mm

14 Biochemical investigation of cartilage using MRI * *

15 - 42 subjects (45-55 years) with - OA risk factors - right knee pain or not - [WOMAC] pain score >/=5) - (Kellgren/Lawrence score </=1) - 3T MRI of the right knee ± 1.8 ms 34.4 ± 1.8 ms

16 MRI of Cartilage [Na + ] = 320 mm T2 Na+ = 2-10ms [H + ] = mm T2 H+ = 30ms Proteoglycans dgemric 23 Na+ Small SNR (long acquisition time) Dedicated coils HF and UHF (High and Ultra-high fields)

17 MRI «ultra high-field»

18 MRI of the wrist at 7 tesla using an eight-channel array coil combined with parallel imaging: Preliminary results. Chang et al. Volume 31, Issue 3, pages , March min 1min

19 23 Na MRI of cartilage (half-degradation experiment) [Na + ] = 316 mm [Na + ] = 261 mm. Shapiro, EM. Et al. Magn Reson Med February; 47(2):

20 Representative sodium maps and proton images. Madelin G et al. Radiology doi: /radiol by Radiological Society of North America

21 Sodium MRI at 3T Resolution Coil availability Cooper et al

22 Coming MRI Quantitative Functional High-field Ultra-high field

23 Research Unit 6612 (CRMBM / CEMEREM) CEMEREM Building 1.5 T 3 T 7 T

24 Quantitative MRI of Knee Cartilage in Osteoarthritis Jean-Pierre MATTEI*, David BENDAHAN *Department of Rheumatology, Sainte Marguerite Hospital, Marseille - France Center for Magnetic Resonance in Biology and Medicine, Marseille - France Main Reference : WHAT LESSONS HAVE WE LEARNT FROM RECENT OA IMAGING STUDIES? F. Eckstein, Institute of Anatomy, PMU, Salzburg, Austria

25 The articular cartilage of human adults composed of : cartilage cell and extracellular matrix including water : weight, 65-80% type II collagen weight, 10-20% proteoglycans weight, 5% or less

26 Fibrillar Collagen Network and aggrecan (chondroitine sulfate proteoglycan) interactions with Hyaluronic Acid (HA) CS DS Type IX collagen Decorin core HA G1 Type II collagen fibril Aggrecan G3 CS KS G2 Link Protein Collagen tensile strength Aggrecan compressive stiffness water binding Diagrammatic representation of the macrofibrillar collagen network and aggrecan superaggregate with hyaluronic acid. (Modified with permission from Poole AR: Cartilage in Health and Disease. In Koopman W [ed]. Arthritis and Allied Conditions. A Textbook of Rheumatology. Ed 14. Vol 1. New York, Lippincott Williams & Wilkins , 2001.)

27 Initial Hurts In The Degenerative Osteoarthritis Loss of glycosaminoglycans Increase of hydric contents Degradation of the collagen network

28 Cartilage Magnetic Resonance Imaging Morphological imaging Information on the thickness and the volume Biochemical imaging Information on the biochemical components of cartilage

29 Cartilage Magnetic Resonance Imaging Conventional imaging T1, T2, STIR, SPGR or FLASH Thickness and volume Hydration and biomechanics Biochemical imaging T2 mapping Integrity of the collagen network Hydration T1 Rho mapping Concentration in collagen and proteoglycans DGEMRIC (delayed gadolinium-enhanced MRI of cartilage) Concentration in proteoglycans

30 Conventional MRI Improving the sequences Cartilage morphology and semiquantitative assessment Optimized Sequences with high spatial resolution T1-weighted SPGR or FLASH (T1-weighted) a relatively long acquisition time Fat-suppressed T2- or intermediate (IM) weighted fast spin-echo (FSE) cartilage surface well depicted steep gradient of signal intensity between the cartilage and the synovial fluid Double echo steady-state imaging (DESS) (T2-weighted ) : SPGR : spoiled gradient echo FLASH : fast low-angle shot

31 Conventional MRI (a) Sagittal fat saturated SPGR image of the knee in a patient with early OA and a cartilage fissure (arrow). (b) Sagittal fat saturated intermediate (IM) weighted image of the same patient

32 Conventional Imaging: Increasing The Magnetic Field Fat suppressed/water excitation gradient echo sequences a et b : 1.5 Tesla c: 1 Tesla d : 3 Tesla

33 Conventional MRI Semi Qantitative Scoring Scores to estimate the severity of cartilage involvement scaled from 0 to 3 or 0 to 4 based on subjective evaluations cartilage lesions of <50% depth, >50% depth and full thickness cartilage lesions MRI scoring system (WORMS whole- organ MRI scoring), cartilage signal and morphology, subchondral bone marrow abnormalities, subarticular cysts, subarticular bone attrition, marginal osteophytes, medial and lateral meniscal integrity, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligament integrity, synovitis/effusion, intraarticular loose bodies and periarticular cysts/bursitis Knee osteoarthritis scoring system (KOSS)

34 Conventional MRI Cartilage Segmentation Methods of semi automatic segmentation Bases: -Region which gets fat -Demarcation of borders -Modelling of the form

35 Segmentation

36 Usual imaging Segmentation

37 Segmentation épaisseur

38 Modeling of the form

39 Performance Segmentation by MRI better than by X-rays: - higher sensitivity and specificity -higher accuracy and precision

40 Biochemical Quantitative Imaging Not only see images, but also quantify the biochemical components of the cartilage

41 T2 mapping T2 : physical quantitative parameter measured in each voxel Construction of a map of the cartilage which reflects the hydration and the integrity of the collagen network Cartilage: weakly hydrated tissue: = > short T2 (30-70 ms) Degenerative osteoarthritis: destruction of the collagen and increase of the hydration = > increase of T2

42 T2 MAP S= S 0 e -TE/T2

43 T2 MaP Takashi Nishii, MD, PhD, Osaka University

44 T2 MAP Takashi Nishii, MD, PhD, Osaka University

45 T2 MAP vs DESS vs Histology

46 T2 MAP

47 dgemeric Imaging Proteoglycans Especially glycosaminoglycans Responsible for the elasticity and for the impact strength of the cartilage Molecules which are negatively loaded and which do not fix the gadolinium Gd-DTPA2-charged negatively Injected by IV (double dose) Binding on the regions where the concentration of glycosaminoglycans falls

48 dgemeric Imaging 90 minutes waiting after the injection of gadolinium

49 dgemric Imaging

50 T1 Rho Imaging T1 slightly different from usual T1 Depends on the concentration in proteoglycans and in collagen When proteoglycans are reduced : T1 Rho increases When the collagen weft gets damaged :T1 Rho increases

51 T1 Rho Imaging

52 Exploring cartilage with MRI Morphology Proteoglycans Proteoglycans and collagen Hydration and collagen

53 Other Techniques Proton imaging : Saturation transfert imaging Diffusion imaging Sodium imaging

54 Quantitative Imaging Advantages Many more information on The volume and the thickness The structure of collagen The contents in proteoglycans The degree of pathological hydration Limits Duration of the examination Dose of Gadolinium Costs