1. Applications of Magnetic Resonance Imaging (MRI) and Computed Tomography CT) Lecture 1 F33AB5

3. What are CT and MRI? CT uses X-rays to produce tomographs (images of slices) MRI uses magnetic fields to probe the intrinsic magnetisation of hydrogen nuclei http://www.mri- ny.com/scannersound.h tml

4. Overview Advantages and problems of each technique Anatomical imaging Functional imaging Phillips

5. Problems of CT Dose (fluroscopy/dynamic mode not possible) (Speed- improving) (3D- now available using helical scanning) Artefacts behind bone

6. Advantages of CT (Limited) soft tissue contrast Spatial measurements exact (if set up correctly)

7. Problems of MRI Not for people who are claustrophobic Not for people with metal in their bodies Susceptibility differences (eg between air and tissue) cause distortions in most sequences, compromising surgical planning Can be slow (not EPI), can have motion artefacts Can be expensive (£750k)

8. Advantages of MRI Excellent (and controllable) soft tissue contrast Much functional information Steerable imaging planes Safe Hugely versatile

9. Anatomical- CT Intracranial bleeds Radiotherapy planning –low geometric distortion –CT contrast relates to radiation attenuation Stereotactic surgery –low geometric distortion Angiography

10. Anatomical- CT Intracranial bleeds Radiotherapy planning –low geometric distortion –CT contrast relates to radiation attenuation Stereotactic surgery –low geometric distortion Angiography Chronic subdural haematoma http://www.radiology.co.uk/xrayfile/xray/tutors/cttrauma/tutor.htm

11. Anatomical- CT Intracranial bleeds Radiotherapy planning –low geometric distortion –CT contrast relates to radiation attenuation Stereotactic surgery –low geometric distortion Angiography

12. Real Time Multi-Trial Window http://www.adaclabs.com/prodSolu/rtp/3dtp/3dtp.shtml Anatomical- CT Radiotherapy planning

13. Anatomical- CT Dose distribution along path shown as histogram colored according to the volumes of interest. http://www.uke.uni-hamburg.de/institute/imdm/idv/publikationen/car1993/ Radiotherapy planning

14. Anatomical- CT Intracranial bleeds Radiotherapy planning –low geometric distortion –CT contrast relates to radiation attenuation Stereotactic surgery –low geometric distortion Angiography

15. Anatomical- CT MRICT CT generally has better geometric accuracy Patient a metal sterotactic frame, ( 'spots' around the head in the images). Streaking artifacts on the CT scans, because of beam- hardening effects. Brain with a deep central tumour Dr Paul Morgan, from Academic Radiology

16. Anatomical- CT Intracranial bleeds Radiotherapy planning –low geometric distortion –CT contrast relates to radiation attenuation Stereotactic surgery –low geometric distortion Angiography

17. Anatomical- CT Left carotid artery showing aneurysm Angiography

18. Anatomical- CT Ascending aortic aneurysm Angiography

19. Anatomical MRI Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy

20. Fetal Brain Placenta Fetal Lung Fetal Liver Anatomical MRI Fetal imaging- brain

21. LR Liver Spleen Kidneys Meal in fundus Meal in antrum Spinal cord Anatomical MRI

22. Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy MRI gives flexible contrast

23. Anatomical MRI Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy

24. Anatomical MRI Orthopaedic MRI (sports injury)

25. Anatomical MRI Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy

26. MR Functional imaging Angiography Pulmonary arteries http://www.cardiac-mri.com

27. Anatomical MRI Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy

28. Anatomical MRI Head (grey/white matter contrast) –Tumours –Multiple sclerosis –Myelination in childhood Orthopaedic (no bone artefacts) –Spine (sagittal views) Great vessels (no contrast agent) Bone and soft tissue tumours and disease Fluroscopy and Microscopy

29. Functional MRI Cardiac MRI End diastole http://www.cardiac-mri.com

30. MR Functional imaging Fluroscopy

31. MRI microscopy Pharmaceutical Dosage Form Castor Bean Seedling Aplysia Neuron Materials Plants (in vivo) Excised samples (in vitro) Professor Bowtell

32. Anatomical MRI and CT Abdominal cancer –rectal –prostate –cervical, uterine –bladder –breast Brain cancer (meninges) Congential heart disease Dementia

33. CT Functional Imaging CT is not a very functional modality However with contrast agents it can measure –perfusion –angiography –renography But- this all requires dynamic repeated scanning… dose is a problem

34. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

35. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

36. Perfusion rate ml/100g/min >1000 500-1000 300-500 <100 MR Functional imaging- Perfusion

37. MR Functional imaging Blood brain barrier permeability

38. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

39. Lung ventilation using hyperpolarized helium MR Functional imaging Tracers Dr Owers-Bradley

40. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times microstructure from diffusion –elastic properties fMRI- brain activation

41. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

42. liquid viscous 36 min48 min72 min Spleen Spinal cord LR Liver Meal Anatomical reference MR Functional imaging Physical properties: T1, T2 Measuring dilution in the stomach

43. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

44. MR Functional imaging Diffusion Staging stroke White matter tracts (diffusion anisotropy) lesion

45. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

46. MRI is a Functional Imaging Technique Perfusion Tracers –Blood brain barrier permeability –Lung function –Molecular imaging? Physical properties of tissues –microstructure from relaxation times –microstructure from diffusion –elastic properties fMRI- brain activation

47. Unit 5 Unit 1 Both digits Unit 7 Unit 8 Both units MR Functional imaging fMRI Which part of your brain senses touch? Dr Francis

48. Fetuses can think too! MR Functional imaging fMRI

50. An MRI study day