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Applications of Magnetic Resonance Imaging (MRI) and Computed Tomography CT)

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

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Applications of Magnetic Resonance Imaging (MRI) and Computed Tomography CT)

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

  2. 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.html

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

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

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

  6. 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)

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

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

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

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

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

  12. Anatomical- CT Radiotherapy planning 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/

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

  14. Anatomical- CT MRI CT Brain with a deep central tumour 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. Dr Paul Morgan, from Academic Radiology

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

  16. Anatomical- CT Angiography Left carotid artery showing aneurysm

  17. Anatomical- CT Angiography Ascending aortic aneurysm

  18. 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

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

  20. Liver Meal in fundus L R Spleen Meal in antrum Spinal cord Kidneys Anatomical MRI

  21. 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 MRI gives flexible contrast

  22. 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

  23. Anatomical MRI Orthopaedic MRI (sports injury)

  24. 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

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

  26. 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

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

  29. MR Functional imaging Fluroscopy

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

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

  32. 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

  33. 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

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

  36. MR Functional imaging Blood brain barrier permeability

  37. 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

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

  39. 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

  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. Liver Meal liquid L R viscous Spleen Spinal cord 36 min 48 min 72 min Anatomical reference MR Functional imaging Physical properties: T1, T2 Measuring dilution in the stomach

  42. 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

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

  44. 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

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

  47. MR Functional imaging fMRI Fetuses can think too!

  48. An MRI study day

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