Principles of Radiology Daniel Podd RPA-C. Physics of Radiology X-Rays produced by electron beam...
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Transcript of Principles of Radiology Daniel Podd RPA-C. Physics of Radiology X-Rays produced by electron beam...
Principles of Radiology
Daniel Podd RPA-C
Physics of Radiology X-Rays produced by electron beam hitting
tungsten film target Electrons strike film, metallic silver is
precipitated if no obstruction to beam, resulting in bright film
Obstruction in path of beam prevents silver precipitation; film remains dark
The negative of this film is known as the Plain X-Ray, or radiograph
Positive Negative (Developed)Radiograph, “Plain Film”
Radiodensity as a Function of Thickness
Radiodensity as a Function of Composition with Thickness Kept
Constant
X-Ray
A-D: Radiolucent or
Radioopaque?
Why?
AP CHEST: Patient Position
AP CHEST
PA CHEST: Patient Position
L: Lung R: Rib T: Trachea AK: Aortic knob A: Ascending aorta H: Heart V: Vertebra P: Pulmonary artery S: Spleen
Lateral
Bullet + PA only = ?
Bullet + PA & Lateral =
Lordotic View
PA Chest
FluoroscopyMechanism: Continuous
below patient, amp- lified by intensifier above patient; broadcast on high-resolution television screen
Provides live animation Imaging reversed vs xray Uses: Barium swallow to evaluate esophagus, small and large intestines, vessel catheter guidance
X-ray beams from
Fluoroscopy
Spot Film: Single X-ray during procedure.Film developed into negative
AngiographyMechanism: Uses X-rays and intravascular
injection of iodinated contrast to evaluate arterial (arteriogram) and venous (venogram)
systems
Vasoocclusive disease
Most approaches via femoral artery or vein
Computerized Axial Tomography Cross-sectional slice radiographs of the body
using thin beam of X-rays through desired axial plane
Slices up to 1.0 mm that represent density values; no superimposed images
Viewed as if facing patient and looking up through feet
Density Less Dense: Air, Fat (black) More Dense: Bone (white)
CT Scan
CT Scan Angiography
3DCT, 3-Dimensional CT scan Injection of IV contrast to enhance
vascular system Useful for aortic aneurysms, coronary
heart disease, carotid vascular occlusive disease
CT Scan Angiography
Ultrasound Mechanism: High-frequency sound waves
beamed directed into body, onto organs and their interfaces; transducer receives and interprets reflection of these beams from organs
Acoustic Impedance: beam absorption by tissues, based on density and velocity of sound through different adjoining tissue types
Ultrasound
Image (echo) produced when different neighboring tissues reflect different acoustic impedances
Solid organs, fat, & stones: Echogenic (white)
Fluid & cysts: Anechoic (black)
Ultrasound
UltrasoundAdvantages
1. No ionizing radiation
2. Applicable to any plane
3. Cost-effective
4. Portable
5. Real-time imaging
Disadvantages1. Time consuming2. Poorer quality
Magnetic Resonance Imaging (MRI)
T1
T2
fat, medullary bone
blood (gray), solid mass, cysts, air, compact bone
tumors, solid masses, CSF, cysts
compact bone, blood, fat, air
Mechanism: Patient placed in magnet tunnel; radio waves passed through body in pulses. Pulses returned from tissues, transformed into 2D image based on relaxing times: T1 & T2
High Signal (brightness) Low Signal
MRIAdvantages vs CT:
1. Multiplanar scanning
2. Better soft-tissue differentiation
3. Contrast-free 3DMR
Contraindications:
Metals, clips, pacemakers
MRI
T1 T2
Normal CXR
NormalCXR
EnlargedHila
Hilar Mass(Left)
Aortic Knob
Right vs Left Pulmonary Artery
Kerley B-Lines
• Fine horizontal opacified lines representing pulmonary edema • Seen in CHF, pulmonary fibrosis, heavy metal fibrosis, malignancy
Blunted Costophrenic Angle
Lung Mass: Cavitation
Lung Mass: Solid Tissue
Air Space (Alveolar) Disease
Interstitial Disease
Alveolar or Interstitial?
Alveolar or Interstitial?
Alveolar or Interstitial?
Lobar Consolidation: Right
• Think anatomically
3 Lobes
RUL and RML located Anterior to heart Obliteration of
mediastinum and cardiac borders
Right CoPhS intact
RLL located Lateral to heart, but anterior to diaphragm Obliteration of right CoPhS Right heart border intact
Lobar Consolidation: Left
LUL lies anterior to heart and superior to diaphragm (and LLL)
Obliteration of left heart border only
Left hemidiaphragm intact
LLL located lateral to heart and anterior to diaphragm
Obliteration of left hemidiaphragm
Left heart border intact
Where Is This Consolidation?
Diaphragm
Gastric Bubble
Diaphragm: Expiration vs Inspiration
Pleura
Anatomically, the visceral and parietal pleura are separated by a potential space, the pleural space
Fluid in this space is known as a Pleural Effusion
Effusions may be large or small, but settle to base of lung due to gravity
Completely obscures aerated lung and heart/mediastinum/diaphragm borders
Pleural Effusion: Large
Pleural Effusion: Small
Pleural Effusion: Small (special case)
Pleural Effusion: Small (special case)
Pneumothorax
Introduction of air into the normal vacuum of pleural space
Radiographic findings:
1. Hyperlucent versus aerated lung 2. Passive atelectasis of ipsilateral
lung
3. Depression of ipsilateral hemidiaphragm
4. Mediastinal shift
Pneumothorax
Optimal Radiographic Images:
1. Expiration film
2. Lateral decubitus film
Pneumothorax
Subtle Pneumothorax
Pulmonary Embolism Lung vessel embolus Radiologic findings:
1. Diminished lung volume Elevated ipsilateral
hemidiaphragm Linear/patchy ipsilateral
atelectasis
2. Completely Normal ! (m/c) CXR to rule out other etiologies
Pulmonary Embolism
Pulmonary Embolism
With Infarction:
1. Hampton’s Hump
Pulmonary Embolism
Perfusion Test (Q) Technetium-99
Ventilation Test (V) Xenon gas
Further Diagnostics
Perfusion/Ventilation mismatch, “V/Q Mismatch”
Pulmonary Embolism V/Q Scan Interpretation 1. Normal Perfusion scan =Rules out PE2. Negative/Low Probability scan (slight
perfusion abnormality or V/Q matching)= Non-embolic pulmonary abnormalities
3. Positive/High Probability= V/Q mismatch4. Intermediate/Indeterminate = Low & High
Pulmonary Angiogram indicated for 3, 4, or 2 with strong clinical evidence
Pulmonary Angiogram
Gold Standard
Helical (Spiral) CT Scan
Indicated for suspected PE with abnormal CXR
CT venogram: Adding IV contrast for concurrent deep leg vein scan
Referenceshttp://www.vh.org/adult/provider/radiology/icmrad/chest/parts/Righthilum.htmlhttp://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/cxr/atlas/cxratlas_f.htmhttp://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/cxr/atlas/hilar.htmhttp://uwcme.org/site/courses/legacy/threehourtour/edema.phphttp://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/cxr/atlas/apwindow1.htmhttp://info.med.yale.edu/casebook/intmed/manditi/test_results.htmlhttp://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/cxr/atlas/normallabeled.htmhttp://www.premedonline.com/Personal_Page/rad.htmlhttp://sfghed.ucsf.edu/ClinicImages/chest_and_pelvis_films.htmhttp://www.virtual.epm.br/material/tis/curr-med/med3/2003/ddi/matdid/cap2.htm
Referenceshttp://www.virtual.epm.br/material/tis/curr-med/
med3/2003/ddi/matdid/cap1.htmhttp://www.fhsu.edu/nursing/cxr/CostoPhrAngCopy.htmhttp://www.aic.cuhk.edu.hk/
web8/0122_CONSOLIDATION_LATERAL_SEGMENT_RML.jpg
http://www.med.wayne.edu/diagRadiology/TF/Chest/CH04.html
http://acbrown.com/lung/Lectures/RsVntl/RsVntlMsclDphr.htm
http://www.nyp.org/masc/images/nl3_ph11.jpghttp://www.lumen.luc.edu/lumen/MedEd/medicine/pulmonar/images/effusion.jpghttp://brighamrad.harvard.edu/Cases/bwh/hcache/116/full.htmlhttp://www.radiology.co.uk/srs-x/cases/094/a.htm
Referenceshttp://brighamrad.harvard.edu/Cases/bwh/images/84/R54A2.GIFhttp://uwcme.org/site/courses/legacy/threehourtour/images/
PTXPA.jpghttp://www.med.wayne.edu/diagRadiology/TF/Chest/CH08.htmlhttp://www.nature.com/ncpcardio/journal/v2/n2/thumbs/
ncpcardio0118-F2.jpghttp://www.vh.org/adult/provider/radiology/icmrad/nuclear/parts/
HiProb.htmlhttp://www.rochestermedicalcenter.com/images/a015.jpghttp://www.engineering.uiowa.edu/~bme185/angiogram.gifhttp://www.vh.org/adult/provider/radiology/ElectricPE/RadImages/03.RT-Angio.gifhttp://www.usask.ca/medicine/imaging/Clinical/GF.shtmlhttp://health.allrefer.com/pictures-images/pancreatic-cystic-adenoma-ct-scan.htmlhttp://www.mia.net.au/perrett/info_general/ct_angio/Image2.jpghttp://www.terarecon.com/gallery/images/us_7_gallstones.jpg