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MedicalImaging Modalities
Methods inMedicalImageAnalysis- Spring2016
18-791(CMUECE):42-735(CMUBME):BioE 2630(Pitt)
Dr.JohnGaleotti
The content of thes e s lides by John G aleotti, © 2012-2016 Carnegie Mellon U nivers ity (CMU ), was made pos s ible in part by N IH N LM
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The mos t recent vers ion of thes e s lides may be acces s ed online via http://itk.galeotti. ne t/
AnatomicalAxes
§Superior =head
§Inferior=feet
§Anterior=front
§Posterior=back
§Proximal=central
§Distal=peripheral
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ImagingModalities
§Camera:Microscope, Endoscope, etc.
§X-Ray
§CT
§NuclearMedicine
§Ultrasound
§MRI
§…
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1896: TheX-Ray
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2
X-Ray&FluoroscopicImages
§ProjectionofX-Ray
silhouetteontoa
detector
§Measuresdensities
§3Dmapsto2D
§Detectorsoftenusean
interveningfluorescent
screentoconvertXraystovisiblelight
§Fat,muscle, bone,
contrastagent,metal
X-RaySource
Patient
Bone
Detector
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ComputerizedTomography
Mikael Häggström’s CT of the human brain with intravenous contrast
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3
ComputerizedTomography
X-RaySource
Spins
around
patient
Patient
Bone
Detector
§Spin X-Raysource/detectoraroundthepatient
§Fromaseriesofprojections, atomographicimage
isreconstructedusing FilteredBackProjection.
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NuclearMedicine
§Previously discussed imagingmodalities image
anatomy(structure).
§Nuclearmedicine imagesphysiology (function)
§ Atthecellular(andsubcellular)level
§ Technicallyatypeofmolecularimaging
§ Requiresuseofradioactivepharmaceuticals
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4
SPECT
Array of Gamma Detectors
Array of Lead Collimators
Spins
around
patient
Patient
Radioactive
Target
§ SinglePhoton EmissionComputedTomography
§ Gammacameraforcreatingimageofradioactivetarget
§ Cameraisrotatedaround patient
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Positron Emission Tomography (PET)
National Institute of Health’s National Institute of Biomedical Imaging and Bioengineering
60 Seconds of Science: How Does a PET Scan Work? CC By License; Music by Longzijun
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5
PositronEmissionTomography
Detectors
-
Patient
+
When emitted positrons
collide with electrons,
their annihilation sends
2 high-energy photons
off in opposite directions
§ Positron-emittingorganiccompoundscreatepairsofhighenergy
photonsthataredetectedsynchronously.
§ Nocollimators,greatersensitivity.
§ Attenuationisnotlocationdependent,soquantificationis
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possible.
MRI
National Institute of Health’s National Institute of Biomedical Imaging and Bioengineering
60 Seconds of Science: How Does an MRI Work? CC By License; Music by Longzijun
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MRI
Kieran Maher’s examples of T1 weighted, T2 weighted, and PD weighted MRI
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PhasedArrayUltrasound
§Imagesanatomy
§Ultrasoundbeamformedandsteeredby
controllingthedelaybetweentheelementsofthe
transducerarray
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RealTime3DUltrasound
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OtherImagingModalities
§MRI&fMRIdetails(savedforanotherlecture)
§OCT(“opticalultrasound”)
§Pathology(inadditiontoRadiology)
§Othermodalities comingdownthepike
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CurrentTrendsinImaging
§3D,4D,…
§Higherspeed
§Greaterresolution
§Measurefunction aswellasstructure
§Combining modalities (including directvision)
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TheGoldStandard
§Dissection:
§ MedicalSchool,Day1:
MeettheCadaver.
§ FromVesaliustothe
VisibleHuman
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