Download X-Rays

Santa Maria University Hospital
Lisbon Medical School
Director: Jorge Campos (MD, PhD)
Applied Radiology and Medical Imaging
Conventional Radiology (X - Rays)
Angiography
Computer Tomography
Ultrasonography
Magnetic Resonance
Conventional and Digital Radiology
Conventional Radiology (X-Rays)
X – Rays Discovery
Wilhelm Konrad Roengtgen (1985)
Conventional Radiology (X-Rays)
Conventional Radiology (X-Rays)
X – Rays Properties
 Penetration – x-rays can penetrate liquids, solids and gases
 Absortion – x-rays are absorbed by matter. Depends on the anatomic
structure of the matter and waveleght of the x-ray beam
 Ionizing Capability – x-rays interact with materials they penetrate and
cause ionization (ex:molecular structure)
 Photographic – x-rays are capable of producing an image on a
photographic film
 Fluorescence – when x-rays fall upon certain materials, visible light will
be emitted
Conventional Radiology (X-Rays)
X – Rays Interaction with matter
Conventional Radiology (X-Rays)
X – Rays
Interaction with matter
Photoelectric effect – a photon
transfers its energy to an electron
Compton effect – only a portion of
the energy is absorbed and a
secondary photon is produced
Conventional Radiology (X-Rays)
Photoelectric Effect – proportional to:
Atomic Number (z)
Density
Thickness
Conventional Radiology (X-Rays)
X – Ray absortion coefficient (same thickness):
Density
Atomic
Number
Absortion
coefficient
Water
1
14
1
Air
0,0013
15
0,001
Soft Tissues
1,01-1,06
12
1,2
Fat
0,92
12
0,8
Bone
1,9
24
18
Conventional Radiology (X-Rays)
Photoelectric Effect
More photoelectric effect
More photons absortion
“White” image
Calcium - Bone
Conventional Radiology (X-Rays)
Photoelectric Effect
Less photoelectric effect
Less photons absortion
“Dark” image
Air - Fat
Conventional Radiology (X-Rays)
Photoelectric Effect
Between White and Dark
there is a gray scale
Digital Radiology
Same Physics
Conventional and Digital Radiology
Nowadays – limited use in clinical practice!
Lung Tumor
Acute Abdomen
Conventional and Digital Radiology
Nowadays – limited use in clinical practice!
Cervical Spine Fracture
Femur Fracture
Radiocontrast Agents
Used to improve the visibility – iodine or barium compounds
High x-ray absortion
Hollow Organs – GI tract – Oral contrasts or Enemas
Oral Contrasts – Barium
Barium Enema
Radiocontrast Agents
Used to improve the visibility – iodine or barium compounds
High x-ray absortion
Intravascular Contrasts (IV or IA) – Iodinated – Risc of Allergy
–
Arterial or Venous System – Angiography or Phlebography
–
Lynphatics – Lymphangiography
–
Urinary Tract – Intravenous Urography/Pielography
–
Biliary Tract – Intravenous Cholangiography
Radiocontrast Agents
Used to improve the visibility – iodine or barium compounds
High x-ray absortion
Lumbar or Cervical Puncture – Iodinated – Risc of Allergy and Seizures
–
Spinal Cord – Myelogram
–
Cisterns ou ventricles – Cisternography or Ventriculography
Almost not used
Radiocontrast Agents
Used to improve the visibility – iodine or barium compounds
High x-ray absortion
Endoscopic and Percutaneous Techniques – Iodinated Contrasts
–
ERCP – Endoscopic Retrograde Cholangiopancreatography
–
Boncography
–
Retrograde Pielography or Cistography
–
Fistulography
–
Percutaneous transhepatic cholangiography
ERCP
PTC
Angiography
Angiography
Technique used to visualize the vascular anatomy, arterial or
venous, injecting a radio-opaque contrast agent – iodine – and
imaging using x-ray based techniques.
Egas Moniz, 1927, Lisbon
•
Direct Puncture
•
Catheterization (Seldinger)
Angiography
Digital Angiography – very fast and accurate image acquisition
Advanced Post processing Software
•
Monoplane ( 1 x-Ray )
•
Biplane ( 2 x-Ray )
Angiography
Digital Angiography – very fast and accurate image acquisition
Advanced Post processing Software
•
Bone subtraction
•
Measurements
•
Virtual arterial endoscopy
Angiography
Digital Angiography – very fast and accurate image acquisition
Advanced Post processing Software
•
Rotational and 3D Reconstruction
Angiography
Diagnostic
Subarachnoid Hemorrhage
Therapeutic
Basilar Tip Aneurysm
Endovascular Aneurysm Coiling
Angiography
Diagnostic
Irregular Carotid Stenosis
Therapeutic
Carotid Angioplasty and Stenting
CT Scan
CT Scan
X-ray
collector
bank rotates
around
patient
X-ray tube
CT Scan
Attenuation Coefficient:
Hounsfield Units (HU) / gray scale
CT Scan
The anatomical image will depend on the Attenuation
Coefficient of the different tissues
Cellularity, Water, Vascularization,
Presence of blood, Calcium, Fat, Air
Hypodense
Isodense
Hyperdense
CT Scan
The anatomical image will depend on the Attenuation
Coefficient of the different tissues
Hypodense
Water, Edema
Hyperdense
Blood, Calcium
Isodense
CT Scan
Iodinated contrast administration gives a better definition of
the lesions – high attenuation - hyperdensity
Ischemia, Tumors, Inflammation,
Vascular Lesions
Benign Tumor - Meningioma
Malignant Tumor - GBM
CT Scan
Abdominal Scan without contrast media
Liver – Homogeneous Cystic Lesions
Liver – Heterogeneous Calcified
Cystic Lesion
CT Scan
Thoracic Scan without contrast media
Tuberculosis Cavity
Bilateral pleural effusion
CT Scan
Abdominal Scan with contrast media
Left Kidney Tumor
Liver Metastasis
CT Scan
Advanced CT Techniques
Bone 3D Recostruction
CT Perfusion - Ischemia
CT Scan
Advanced CT Techniques – Angiographic Studies
Cervical Vessels
Inferior Aortography
CT Scan
Advanced CT Techniques
Virtual Colonoscopy
Virtual Bronchoscopy
Ultrasonography
Ultrasonography
Piezoelectric Crystals
Produce and receive the sound
• Ultrasound frequency and Crystal size:
- big crystal – low freq.
- small crystal – high freq.
• High Freq. (7-10 MHZ)
better resolution, less penetration
– ex. Thyroid
• Low Freq. (3,5-5 MHZ)
less resolution, more penetration
Ultrasonography
US Propagation Speed
Depends on the medium (density and hardness)
In soft tissue averages 1540 m/s
Tissue
–
–
–
–
–
–
–
Liver
Kidney
Muscle
Blood
Fat
Lung
Bone
1555
1565
1600
1560
1460
600
4080
Ultrasonography
US Attenuation (dB/cm)
Weakening of sound as it propagates
Includes absortion (heat) and reflection and scattering (tissue interfaces)
US Impedance (Rayl)
Determines the intensity of the reflected echoes and the transmited pulse
Equal the density of a medium x propagation speed
If impedances are equal there is no echo
If there is a large difference there will be total reflection – air/soft tissue interf.
US Reflection
Results from the interface of tissues with different impedances
Forms the image – Returning echoes
Ultrasonography
US Impedance (Rayl)
Tissues - Impedance
Ar
Água
Gordura
Fígado
Rim
Músculo
Sangue
Pulmão
Osso
RAYLS
0,0004*10
1,48*10
1,34*10
1,65*10
1,63*10
1,71*10
1,65*10
0,18*10
7,8*10
Ultrasonography
Clinical Ultrasound
•
Abdomen
–
•
Pelvis
–
–
•
Thyroid, lymph nodes, Vascular Structures (Doppler)
Musculoskeletal
–
•
Heart, lung, pleura, breast
Neck
–
•
Uterus, ovary, prostate, bladder, scrotum
Obstetrics – fetal development
Thorax
–
•
Liver, spleen, kidney, digestive tube
Muscles, tendons, ligaments, meniscus, sinovial
CNS
–
Neonatology - transfontanelar, Transcranial Doppler
Ultrasonography
Clinical Ultrasound
Anechoic Lesions – liquid, cystic – “black”
Liver Cyst
Kidney Cyst
Ultrasonography
Clinical Ultrasound
Solid Lesion – hypo or isoechoic - grey
Liver Nodule
Ultrasonography
Clinical Ultrasound
Mist Lesion – anechoic/isoechoic – solid and liquid
Liver Hidatid Cyst
Ultrasonography
Clinical Ultrasound
Calcified Lesion – hyperechoic – white
Renal Lithiasis
Gallbladder Lithiasis
Posterior cone shadow
MRI
MRI
Spinning Protons – magnets
Parallel – low en.
Anti-Parallel – high en
MRI
•
•
•
•
•
•
•
•
•
RF is turned on
Protons absorb energy
Align in XY plane
Magnetization is measurable
RF is turned off
Spins re-align with Bo
Relaxation
Electric currents
Receiver Coils
MRI
T1 Relaxation Time – Longitudinal – Spin/Lattice
Short T1 – White – Fat
Long T1 – Dark – Water or Calcium
T2 Relaxation Time – Transverse – Spin/Spin
Short T2 – Dark – Fat or Calcium
Long T2 – White – Water
MRI
T1WI – Short TE and TR
T2WI – Long TE and TR
TR – Repetition Time
TE - Echo Time
MRI
Water
Proteins
Fat
Calcium
Air
Fibrosis
Tumors
Liver
Spleen
Subacute Blood
Sinal T1
Hypo
Hyper
Hyper
Hypo
Hypo
Hypo
Hypo
Iso
Hypo
Hyper
Sinal T2
Hyper
Hyper
Hypo
Hypo
Hypo
Hypo
Hyper
Iso
Hyper
Hyper
MRI
The administration of contrast media – Gdollinium – will shorten the T1
relaxation
Cellularity, Water, Vascularization,
Presence of blood, Calcium, Fat, Air
MRI
CNS
Subacute Blood
MRI
Liver
Cystic Lesion - Benign
MRI
Lung
Right Lung Infiltrative Lesion
MRI
CNS – Contrast Enhancing Lesion
Malignant Tumor
MRI
Liver – Contrast Enhancing Lesion
Hemangiomas
MRI
Other Sequences and Advanced MRI
FLAIR – T2WI with CSF signal suppression
T2* - T2WI – enhances magnetic susceptibility
“Blooming effect”
MRI
Other Sequences and Advanced MRI
Diffusion WI – T2 echo planar,
Restriction to water random movement
acute ischemia/ abcess
Perfusion
MRI
Other Sequences and Advanced MRI
MR Angiography
MRI
Other Sequences and Advanced MRI
fMRI – T2 EPI
MRI
Other Sequences and Advanced MRI
Spectroscopy