1. LIVER MRI MANDATORY SEQUENCES P.Zerbib, A.Luciani, F.Pigneur, A.Rahmouni Henri Mondor Hospital – Créteil, Paris Radiology Department Pr.A.RAHMOUNI

2. Objectives  Define a standardized protocol for the evaluation of :  Liver focal lesions  The Biliary system

3. 1. Liver focal lesions study

4. Mandatory sequences to perform a good liver MR T1-w T2-w Injection Diffusion

5. T1-w ? T2-w ? Injection ? Diffusion ? Mandatory sequences to perform a good liver MR

6. IN AND OUT OF PHASE SEQUENCE – GRADIENT ECHO T1-w

7. PRINCIPLE EG TE=2.4 ms (1.5T) E G TE=4.8 ms (1.5T) Fat Water 220 HZ (1.5T) Fat poor substance No SI decrease in out of phase sequence TE=4.8 ms (In of phase) TE=2.4 ms (Out of phase) Fat rich substance (steatosis) SI decrease in out of phase sequence 63.5Mh z

8. Fast SE-T2 with SPECTRAL FAT SUPPRESSION

9. PRINCIPLE  T2-w sequences allow the detection of liver lesions (water rich substances)  Time of echo= 70-100 ms

10. 100ms SE FastSE 100ms TR PRINCIPLE 20ms 40ms 100ms 60ms 80ms TR K space

11. PRINCIPLE  This sequence is performed with spectral fat suppression

12. PRINCIPLE  First echo < 70ms : DETECTION  Second echo >100ms: CHARACTERIZATION long First echo Signal

13. PRINCIPLE  First echo < 70ms : DETECTION  Second echo >100ms: CHARACTERIZATION long First echoSecond echo Signal

14. PRINCIPLE  First echo < 70ms : DETECTION  Second echo >100ms: CHARACTERIZATION long First echoSecond echo First echo Second echo Liver-lesion contrast increment Liquid/angiomatous lesions T2-w Signal Time of echo Hepatic T2 Liver Hemangioma Signal

15. DIFFUSION SEQUENCE

16.  The purpose of diffusion sequences is to: 1. Detect small lesions hard to see in the others sequences 2. Characterize diffusion zones of restricted diffusion (eg: metastasis) from those with non restricted diffusion (eg: kystic lesions) PRINCIPLE

17. Restricted DiffusionUnrestricted diffusion Principles of diffusion

18.  In the zones of restricted diffusion, signal intensity increase when diffusion gradient intensity (b) increase Restricted range of motion protons SIGNAL INTENSITY Free range of motion protons 180° Diffusion gradients (b = s/mm²) PRINCIPLE EPI-SE

19. bo b200 b10 b50 b20 b100 b400 b30 b800

20. RESTRICTED DIFFUSION ELEVATED DIFFUSION b (s/mm²) SIGNAL INTENSITY ADC = (1/b1-b0) ln (S[b1]/S[b0])

21. ADC high signal intensity = no diffusion restriction = non suspect lesion ADC low signal intensity = diffusion restriction = suspect lesion

22. Signal Analysis b50b400b800ADC Benign lesions Suspect lesions Effet T2 « shine through » b50 b800 ADC b50 b800 ADC

23. b50b400b800ADC Benign lesions Suspect lesions «Shine through» T2 effect Air Présence de fer b50 b800 ADC b50b800

24. FAST GRADIENT ECHO T1 3D SEQUENCES WITH FAT SUPPRESSION BEFORE AND AFTER CONTRAST MEDIUM ADMINISTRATION

25. Arterial Portal Before Gd Venous Focal Nodular Hyperplasia (FNH) PRINCIPLE GE 3D T1 : Rapid acquisition K space partial filling T1-weighted images Gadolinium injection

26. T1Dynamic GE - 3D Contrast enhancement Temporal and contrast resolutions

27. 2. Biliary system abnormalities detection and/or characterization

28. Two sequences to study the biliary system: 1. Half-Fourier acquisition single-shot turbo spin- echo T2-weighted (HASTE) Liver and pancreatic morphologic study and biliary tract exploration 2. 2D or 3D RARE sequence (long TE) Biliary system global visualisation

29. PATIENT PREPARATION  Patient fasting (to avoid gastric and duodenal artifacts) Fasting No fasting

30. HALF-FOURIER ACQUISITION SINGLE-SHOT TURBO SPIN-ECHO (HASTE)

31.  Half Fourier acquisition (Turbo Spin Echo T2 Single shot)  Half symmetric reconstruction PRINCIPLE K space symmetry Axial and coronal acquisitions

32. RARE SEQUENCE (BILI) (RAPID ACQUISITION RELAXED ENHANCED) PRINCIPLE

33.  Turbo spin echo sequence with very high TE (>1000ms)  Signal intensity decrease with TE High slice thickness (30 à 50 mm) Signal TE Signal intensity TE (ms)

34. Conclusion:  Technique comprehension is mandatory to adapt MRI protocole for each patient and each disease  Gradients quality improvements and new technologies permit to improve the diagnostic degree and to reduce the acquisition time

35. שעזר לי להכין את הפרזנטציה הזו ב עברית אני מודה אילון להט,מנתח בבית חולים מונדור בפריז,

37.  Explain the exam and reassure the patient  Taking some time to explain the essentials of the upcoming MR examination process allows to save many minutes during the examination and decreases the rate of failures  Motivate the patient : “The pictures could be fuzzy”, “I will talk with You during the exam”, …  Explain that some sequences need breath-hold, and on the opposite that some sequences will require a regular breathing PATIENT PREPARATION

39. 4. Fast 3D GE sequence with spectral fat suppression before and after contrast medium administration (With parallell reconstruction techniques such as Caipirinha) 1. 2D GE T1-w sequence in and out of phase (In- Phase – Out-of-Phase) 2. Fast SE T2-w sequence with spectal fat suppression / HASTE 3. Diffusion sequence To detect a signal intensity decrease in the out-of-phase acquisition due to liver fat content To increase the signal intensity difference between liver and lesion To explore the intra-hepatic biliary system and the principal biliary tract To detect and characterize hepatic lesions To study liver parenchymal enhancement and liver vascularization

40. Why not a gradient echo T2 acquisition ? Signal to noise ratio decrease in Gradient Echo because of liver iron content (susceptibility artifact) Spin Echo Gradient Echo

41. Why not a Spin Echo T1 acquisition ? impulsions Gsc GpGp Gl Signal intensity 90° Signal intensity Gl GpGp 180° Gs GE SE TE In and Out of phase sequence use short TE (2 - 4 ms) Spin Echo sequence is not used because of 180° 90°

42. Toronto Consensus conference (2008) recommend: b values between 100 and 750 s/mm² (to remove low b signal due to microperfusion) at least 3 b values utilization, included b0, b ≥100 s/mm² and b ≥ 500 s/ mm²

43. bo b200 b10 b40 b20 b100 b400 b30 b800 Low b values evaluate the microcirculation

44. Toronto Consensus conference (2008) recommend: b values between 100 and 750 s/mm² (to remove low b signal due to microperfusion) at least 3 b values utilization, included b0, b ≥100 s/mm² and b ≥ 500 s/ mm²

45. Toronto Consensus conference (2008) recommend: b values between 100 and 750 s/mm² (to remove low b signal due to microperfusion) at least 3 b values utilization, included b0, b ≥100 s/mm² and b ≥ 500 s/ mm²

46. bo b200 b10b20 b100 b400 b30 b800 DD*

47. Toronto Consensus conference (2008) recommend: b values between 100 and 750 s/mm² (to remove low b signal due to microperfusion) at least 3 b values utilization, included b0, b ≥100 s/mm² and b ≥ 500 s/ mm²

48. bo b200 b10b20 b100 b30 b800 b400 b50

49. GE T1-w sequence with fat suppression  Fat suppressed GE T1-w realized after dynamic acquisitions:  Use fat suppression to increase focal enhancement  To study parenchymal liver enhancement after Gadolinium injection  To show late focal enhancement axialcoronal

50. bo b200 b10b20 b100 b30 b800 b400 b50

51. HALF FOURIER and applications SS FSE (GE) SS TSE (PHILIPS) HASTE (SIEMENS)

52. GE T1 SEQUENCE WITH INTERPOLATION LAVA (GE) WAVE (PHILIPS) VIBE (SIEMENS)

53. bobines Bobines de gradients B.KASTLER COMPRENDRE L’IRM B0