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MR Venography Ivan Pedrosa, M.D. Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA.

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Presentation on theme: "MR Venography Ivan Pedrosa, M.D. Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA."— Presentation transcript:

1 MR Venography Ivan Pedrosa, M.D. Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA

2 Why MR Imaging? Conventional venographyConventional venography –Multiple injections –I.V. access in affected edematous extremity –Radiation / iodinated contrast US US –Limited in central veins –Limited FOV and anatomic landmarks

3 Why MR Imaging? CTCT –Radiation –Iodinated contrast –Pitfalls due to poor opacification / mixing artifacts Nephrogenic Systemic Fibrosis (NSF)Nephrogenic Systemic Fibrosis (NSF) –Increased indications for non-contrast MRV

4 MRV TechniquesTechniques –Dark Blood Imaging –Bright Blood Imaging –Gd-enhanced MRV Clinical ApplicationsClinical Applications –Chest –Abdomen –Pelvis

5 MRVtechniques Non-contrast MRV Dark blood Sequences Bright blood Sequences Double IR Spin echoTOF Double IR SSFSEGRE (Cine) Dynamic SSFSEFIESTA (Cine) Phase Contrast Gd-enhanced MRV 3D FS T1-W GRE ( VIBE, LAVA, THRIVE)

6 Spin Echo (“dark blood”) 180º 90º 180º

7 HAlf-Fourier Single shot Turbo Spin Echo (HASTE or SSFSE) SSFSE/HASTE One second to collect the whole image Dark blood Protons exit slice Slow flow - ↑↑ SI Thrombus - ↓↑ SI K space 90º 180º

8 Dynamic HASTE Intravascular signal void VALSALVA Valsalva –  intrathoracic P –  Venous return T2 of blood is long

9 Valsalva –  intrathoracic P –  Venous return T2 of blood is long Dynamic HASTE VALSALVA

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11 DB HASTE (“dark blood”) 90º 180º TI 180º TI

12 Double IR T1 FSE IR-T1W Cardiac-gated IR-HASTE 1 slice (~16 sec) breath-hold~20 slices ( sec) breath-hold 2 slices with ASSET

13 Bright blood Sequences TOF GRE (Cine) FIESTA (Cine) Phase Contrast

14 Time-of-Flight (TOF)

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22 TOF

23 TOF optimization for slow flow

24 TOF: in-plane saturation Axial acquisition Sagittal Gad-MRV

25 TOF optimization for slow flow Slice perpendicular to vessel of interest Decrease slice thickness Cardiac gating? ECG Tracing Blood flow (Pulse Oximeter) Systole (arterial)

26 True FISP / FIESTA / Balanced FFE True Fast Imaging with Steady-state Precession Gradients are fully balanced in order to recycle the transverse magnetization in long T2 species Contrast –T2 / T1 ratio –Blood vessels are bright –Blood vessels are bright (T2 of blood is  )

27 True FISP Pros Fast –Road map No breathing artifacts Thrombus –Filling defect  SI Cine True FISP –FIESTA Cons Artifacts –Pulsatile flow –Off-resonace Acute / subacute thrombus

28 True FISP

29 True FISP Gd-enhanced MRV

30 True FISP True FISP Gd-enhanced MRV L Pedrosa I. AJR 2005

31 Phase Contrast (PC) 2 equal and opposite Venc gradients between the excitation and echo. With stationary protons, phase shifts induced by the first gradient are reversed and canceled by the second gradient. In moving protons, the second gradient does not quite cancel out phase shifts induced by the first gradient These phase shifts are detected and proportional to the amount of motion in the direction of the encoding gradients

32 Phase Contrast (PC) Venc gradient applied in the slice (superior-inferior) direction In the phase (velocity) image –Gray represents stationary background tissues –White represents blood flowing caudally (towards feet) –Black represents blood flowing cranially (towards head) –The intensity of white or black represents the magnitude of velocity in the respective directions Phase Image Magnitude Image High velocity flow towards the head (Ascending aorta) Moderate velocity flow towards the head (Pulmonary artery) Moderate velocity flow towards the feet (SVC) High velocity flow towards the feet (Descending aorta)

33 Phase Contrast (PC) If Venc is chosen to be too low, aliasing (“wrap-around artifact”) occurs when velocities exceed that value causing velocities to mimic a “lower” value If Venc is chosen to be too high, sensitivity to slow flow and accuracy of quantitative analysis of velocity/flow are diminished Venc for venous imaging? –40-60 cm/sec Venc set to 140 cm/sec, appropriate for this volunteer Venc set to 70 cm/sec, too low for this volunteer. Aliasing or “wrap-around” results in the high-velocity flow areas of the aorta. Phase Images

34 Phase Contrast (PC) Venc = 40 cm/sec

35 Phase Contrast (PC) 3D PC

36 Gadolinium-enhanced MRV Indirect MRVIndirect MRV Direct MRVDirect MRV

37 Indirect Venography I.V. access in any peripheral veinI.V. access in any peripheral vein –Antecubital vein (Right UE) GadoliniumGadolinium –Single dose (~20 2 cc/seg –Single dose (~ cc/seg –20 cc 0.8 cc/seg 3D GRE T13D GRE T1 SubtractionsSubtractions –Venogram-like MIP reconstructions Double dose Gd Single injection/dual rate

38 Timing arterial phase

39 Indirect Venography VENOUS PHASE SUBTRACTION - = ARTERIAL PHASE

40 Indirect Venography SUBSTRACTION MIP

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42 Direct Venography I.V. access in affected extremity or bilateral Gadolinium –5 cc Gd in 100 cc saline (1:20) Tourniquet in lower extremities 3D GRE T1 Li W et al. J Magn Reson Imaging 1998; 8(3): 630-3

43 Direct Venography

44 Thrombus Characterization –Bland thrombus – No enhancement – Variable SI –Tumor thrombus –Enhancement on Gd-MRV »Subtractions! »Absence of enhancement does NOT exclude tumor thrombus –  SI on T2-weighted images

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46 Tumor thrombus: Intravenous leiomyomatosis U

47 Staging Acute thrombusAcute thrombus –Enlargement of vein by intraluminal thrombus –  SI on T2-weighted images Vessel wallVessel wall ThrombusThrombus –Perivascular soft tissue edema –  SI on T1-weighted images (subacute) Chronic thrombusChronic thrombus –Vein attenuated or not visible –Venous collaterals –↓ SI on all sequences

48 Acute thrombosis of the portal vein

49 T2W T1W post-contrast

50 Paget von Schrotter syndrome or “effort” thrombosis

51 Chronic Thrombosis

52 Venous thrombosis Is the thrombosis acute or chronic? Do I need to anticoagulate this patient?

53 Acute/subacute thrombosis

54 brachiocephalic vein: chronic occlusion

55 Central catheter malfunction Fibrin sheath

56 Clinical Indications

57 SVC syndrome

58 Venous Access Central cathetersCentral catheters –Hemodyalisis –Chemotherapy –Parenteral nutrition –Thrombosis in first 3 months (10%) MRV chestMRV chest –15 pts with occlusion or stenosis central veins –Venous access possible in 14 pts Shinde TS et al. Radiology 1999;213:

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61 51 yo male with PE Papillary carcinoma IVC in Renal Cell Carcinoma

62 Pulmonary Embolism

63 Isolated Iliac Vein DVT

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66 Conclusion Central veins of the chest, abdomen and pelvisCentral veins of the chest, abdomen and pelvis –Limited evaluation with US Whole-body venous roadmapWhole-body venous roadmap –Vascular access PregnancyPregnancy


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