Les indications incontournables de l IRM en 2013

Transcription

1 Les indications incontournables de l IRM en 2013 P. Croisille CHU Saint-Etienne - Université Jean Monnet Université de Lyon CREATIS UMR CNRS 5515 / INSERM U èmes Journées Nationales du GACI jeudi 28 & vendredi 29 mars Paris

2 Corrélation morphologie (coronarographie et CT angio) vs. fonctionnelle (FFR) de la sténose coronaire Diagnosis accuracy Quantitative coronary angiography 65% Quantitative CT angiography 67% 79 pts stable angina 89 stenosis (18% FFR 0.75, 34% FFR 0.80) Meijboom et al. JACC 2008;52:636

3 FAME 2 Hypothesis: superiority of FFR-guided PCI + OMT vs OMT only in stable angina (with drug eluting stents)? recruitment halted prematurely 1220 randomized patients (888 randomized w/ FFR<0.8, others registry) Cumulative primary end-points: death, MI, urgent revascularization FFR<.8 FFR>.8 «la revascularisation devrait être guidée par la présence d une ischémie myocardique et non par l aspect angiographique»

4 2 champs d exploration incontournables recherche d une ischémie myocardique +++ recherche d un viabilité myocardique

5 Protocole-type d IRM pour détection de l ischémie (stress adénosine) 140 µg/kg/min infusion 6 min Fonction VG 4 min Perf stress DE Perf rest 6 min min 10 min durée totale: respect des consignes (café, thé...) Bolus Gd 0.05 à 0.1 mmol/kg P.Croisille

6 70 y.o. female chest effort in the last 6 months ambiguous treadmill exercise test LVEF=71% EDVi=54ml/m 2 ESVi=16ml/m 2

7 stress rest DE

8 Before PTCA 2 months after

9 comparison CMR adenosine vs. SPECT for CAD dectection GS= coronary angiography (stenosis >50%) 18 centers, multivendors, 241 patients

10 n=752 patients angina and 1 risk factor (prevalence CAD 39%) in randomized order tetrofosmin SPECT, CMR and Cath (no FFR) Texte CMR Se: 86.5% Sp: 83.4% PPV: 77% NPV: 90.5% SPECT Se: 66.5% p<0.001 Sp: 82.6% PPV: 71% NPV: 79% p<0.001

11 SPECT vs. FFR Forster et al. Int J Card imaging (2010) 26: Melikian et al. JACC interv (2010) 3; 3:307 Se: 76% Sp: 38% PPV: 66% NPV: 50% concordance FFR(<.8) and reversible ischemia with SPECT in 42% of the cases 67 pts (201 territories) 2- ou 3- vx disease over-estimation: 22% under-estimation:36%

12 CMR vs. FFR IRM adenosine, 0.1mmol/kg Gd, SR-TFL, quantification (slope ratios) Watkins et al Circulation 2009;120:2207 n=103 Lockie et al JACC 2011:57:70-5 n=42 Se: 82% Sp: 94% Az:0.92 PPV: 83% NPV: 94%

13 Stress CMR for risk stratification dobutamine Stress CMR conveys a similar prognostic value to nuclear and dobutamine echo 1% events/y CMR adenosine increased «warranty period» with DSMR+MRP 0.8%/3 years P.Croisille

14 2 champs d exploration «incontournables» recherche d une ischémie myocardique mesure de la taille d infarctus et recherche d un viabilité myocardique

15 Infarct size is a strong determinant of prognosis and mortality years Gibbons et al. JACC (2004) 44: Miller, et al Circulation (1995)

16 (Kim Circulation, 1999; 100: CMR=gold-standard for accurate imaging of the transmural, circumferential and longitudinal scar imaging

17 LGE imaging: «cell non-integrity» increased extracellular distribution volume increased wash-out time 17

18 When to measure infarct size Day 1 Day 7 Day 35 Day 180 n=17 In humans, infarct size 7 days after reperfusion closely match that at 35 and 180 and allows measurement of the final infarct size after the acute event. 18 Ibrahim et al. Radiology (2010) 254: 88-97

19 Validation of infarct size measurement Animal studies Ex-vivo CMR vs. TTC In-vivo CMR vs. TTC Kim et al. Circulation (1999) 100: R=0.96 Bias:0.24%; LOA:[+8 ; -7.6]% LV (n=24) Fieno et al. J Am Coll Cardiol (2000) 36:

20 Infarct size reproducibility inter-study reproducibility in chronic MI MRI vs SPECT -0.1±2.4 vs -1.3±4%LV +2SD method, same inj. inter-study and multi-center reproducibility (3 centers, n=48) -bias: 0±1.6 %LV scan1(5min) & scan2 (30 min w/ TI adj) Mahrholdt et al. Circulation (2002) 106: inter-study, inter/intra-observer reproducibility in AMI and chronic mri1-mri2 acute:-0.7±3.2%; chronic:-0.4±1.3% intra:0.3±1.7% inter:-0.7±2.2% planimetry; 2 days Thiele et al. J Am Coll Cardiol (2006) 47: SD method, same inj. Wagner et al. J Am Coll Cardiol (2006) 47:

21 Mr Par. P. 51 ans coronarien avéré douleurs thoraciques à l effort

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23 FEVG 49% / VTDi 84ml/m2 / VTSi 43ml/m2

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27 procédure CTO

28 IRM perfusion J30 post-angioplastie

29 Mr Boual. Syndrome douloureux thoracique constrictives sans irradiation récidivantes 3-5h depuis 2-3j syndrome grippal il y a 15 j sus-décalage / Q antérieur Plus de douleurs troponine 25 28

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31 T2 STIR 30

32 imagerie T1 précoce (3min) 31

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35 T2 mapping: temps de relaxation T2 >60ms 34

36 3 critères: -oedème (T2) -hyperhémie (EGE ratio) -lésion myocytaires (LGE)

37 combinaison imagerie T2, early GE et late GE (+++) localisation intramurale ou épicardique (rim-like ou patchy) LGE ne permet pas d identifier le stade de la maladie ( T2)

38 T2w imaging as a retrospective measure of the AAR: feasability clinical study 92 patients reperfused AMI; T2w imaging 3±3 days after perfusion; 19 controls (256 2, 15mm, body coil) +2SD method Friedrich et al. J Am Coll Cardiol (2008) 51:

39 Common artefacts with DB-TSE (STIR): - inhomogeneity due to surface coil sensitivity variations - stagnant sub-endocardial blood (apex) - myocardial motion-related artefacts (signal drop or pseudo-hypersignal ) Wince et al Nat Rev Cardiol (2010) 7: Incorrect results in up to 28% of the cases after MI 38 Kellman et al. Magn Reson Med (2007) 57:

40 In a randomized controlled study, treatment (postconditionning) induce changes in the amount of oedema (a marker of reperfusion injury) 39 Thuny JACC 2012,

41 Conclusion méthode non-invasive de choix pour la détection d une ischémie évolutive méthode référence pour la quantification de l infarctus et l évaluation d une viabilité myocardique méthode de référence pour le diagnostic différentiel de myocardite 40