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MRI: State of the Art

MRI: State of the Art. MR Attractions. MRI 的特點. 非侵入性 MRCP MR Myelography. 無輻射. 任意斷層切面. T2. 組織對比. 信號抑制. MR 血管攝影. No CM Necessary Replacing Diganostic Angio Vasculatures beyond Brain. 安全的造影劑. 最安全 健保給付. Tissue Contrast. TR. 2500 500. TE. 15. 90. T1,T2 & PD.

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MRI: State of the Art

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  1. MRI: State of the Art

  2. MR Attractions

  3. MRI的特點 • 非侵入性 • MRCP • MR Myelography • 無輻射

  4. 任意斷層切面

  5. T2 組織對比

  6. 信號抑制

  7. MR 血管攝影 • No CM Necessary • Replacing Diganostic Angio • Vasculatures beyond Brain

  8. 安全的造影劑 • 最安全 • 健保給付

  9. Tissue Contrast

  10. TR 2500 500 TE 15 90 T1,T2 & PD

  11. Spin-Echo, Gradient Echo

  12. SE, TSE & EPI SE: 7 min TSE: 2 min EPI: 0,2 s

  13. Echo Planar Imaging • Single shot EPI • Uncooperative patients • Ultra-fast imaging • Stroke Imaging • Separation of old versus new infarctions • Online calculation of Trace & ADC maps • Up to 16 b - values: 0 - 4000 • Perfusion imaging • Online calculation of global bolus plots, TTP maps ? ?

  14. Restrictions • Magnetic Field • Safety: 5 Gauss Fringe Field • Superconductive Magnet︰Weight, Price • Scan Time • Know-How • Longer Training Time • Operation of MR Center

  15. Functions What MRI can do? • Images • Spectroscopy

  16. Functional MRI • Restrictions of Medical Imaging • Lesion Detection • Function Indicators︰ • Example -- GPT、GOT • Cardiac Function – Myocardial Perfusion • Brain Function – Diffusion & Perfusion • Images＋Functional Studies  functional MRI

  17. Functional MR Imaging T2W TSE T2W FLAIR DWI SE-EPI rCBV post Gd T1W SE PCA - angio

  18. Spectroscopy • Images vs Spectra • OrgansTissuesCellsMolecules • Active Metabolism on Tumor • Unusual Concentration Metabolites • Tumor Phasing • Radiotherapy follow-up

  19. Brain Tumor Images＋Spectroscopy

  20. MR Imaging

  21. From Pixel to Images

  22. speed MR System Components Receiving Bandwidth RF system (coils, pre-amp, etc.) Gradients Computer SNR flexibility magnet

  23. 1,5 T 160 cm magnet

  24. Gradient systems „Stronger and faster“ Required for advanced applications like EPI and contrast enhanced MR-Angio Level of peripheral nerve and muscle stimulation is reached. Searching for compromises regarding amplitude, rise time, FoV, linearity.

  25. Gradient Amplifier Amplitude: 40 mT/m Slew Rate: 200 T/m/s Rise Time: 200 s Max. 40 cm FOV • Voltage: • max. 2000 V • Current: • max. 500 A • per axis • (1 MW / axis)

  26. 15 kW Pulse power • 600 W average power • System control compensates for nonlinearities and phase errors RF Amplifier

  27. RF - Coils Using a larger number of local coils, the s/n can be improved significantly in peripheral regions but not in the center of the patient.

  28. CP Body Array and CP Spine Array Coil Coil Combinations

  29. =  + +  = + =  + + + =  Coil Family Be creative!

  30. Sequence Family EPI TGSE MP RAGE TSE turboFLASH HASTE PSIF CISS DESS trueFISP FISP TIRM QUEST FLASH SSFP STEAM IR GRE SE SE

  31. TGSE True-FISP 3D-TOF-Angio 3D-FLASH Turbo-FLASH

  32. 1H-SVS PC.Angio Flow Koronarien EPI-Func. Imaging Diffusion-EPI

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