1. Jalal jalal shokouhi – MD General secretary of Iranian society of radiology President of Iranian radiologists cooperative 17th -18th December 2010, Shahid beheshti university, Tehran, Iran jalaljalalshokouhi@hotmail.comjalaljalalshokouhi@hotmail.com www.medimage.ir www.medimage.ir jalaljalalshokouhi@hotmail.comwww.medimage.ir

2.  MRA ○ Black Spine echo. ○ White TOF Phase contrast Contrast enhanced  Motion related MRA ○ TOF ○ Phase contrast

3. TOF Continuous excitation  non moving tissue saturation and loosing signal  increased moving blood signal:  2D: high velocity blood  3D : high and low velocity blood

4. TOF  Advantages: 5min (short time) Slow flow sensitivity Reduced sensitivity to intra-voxel dephasing  Disadvantage : Sensitive to T1 effects (methemoglubin) Saturation in phase flow Enhancement is limited in flow entry, very high flow

8. 2D TOF – MRI Advantages: Large area of coverage Sensitive to slow flow Sensitive to T1 effects (methemoglubin) Disadvantage: Low resolution Saturation of in-phase flow Ventetian artifact (respiratory and patient motion) Tissue in and out of the slice

23. 3D TOF-MRI Advantages: High resolution for small vessels Sensitive to T1 effects (Met.) Disadvantages: Saturation in-plane flow Small area coverage 4D flow sensitized in 3T and 7T High vessel to tissue contrast High spatial resolution(0.3 - 0.7 mm lenticulostriate vessels) High SNR

24.  MRA image reformations: 1. MIP 2. SSD

25. MRA summary Techniques  Phenomenon  MRA, TOF, PC DSA Flow Sensitive Sensitive +- Anatomy ++ Hemodynamic ++++ Doppler effect +- Conclusion  MRA = DSA + Color doppler

26.  indications in intracranial TOF 3D>2D, 4D>3D  indications in neck vessels TOF 3D>2D + PC 3D + CE+++ > TOF and PC +