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Principles of Radiology Daniel Podd RPA-C. Physics of Radiology X-Rays produced by electron beam hitting tungsten film target Electrons strike film, metallic.

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Presentation on theme: "Principles of Radiology Daniel Podd RPA-C. Physics of Radiology X-Rays produced by electron beam hitting tungsten film target Electrons strike film, metallic."— Presentation transcript:

1 Principles of Radiology Daniel Podd RPA-C

2 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

3 Positive Negative (Developed) Radiograph, Plain Film

4 Radiodensity as a Function of Thickness

5 Radiodensity as a Function of Composition with Thickness Kept Constant

6 X-Ray A-D: Radiolucent or Radioopaque? Why?



9 AP CHEST: Patient Position


11 PA CHEST: Patient Position


13 L: Lung R: Rib T: Trachea AK: Aortic knob A: Ascending aorta H: Heart V: Vertebra P: Pulmonary artery S: Spleen

14 Lateral

15 Bullet + PA only = ?

16 Bullet + PA & Lateral =

17 Lordotic View PA Chest

18 Fluoroscopy Mechanism : 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

19 Fluoroscopy Spot Film: Single X-ray during procedure. Film developed into negative

20 Angiography Mechanism : 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

21 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)

22 CT Scan

23 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

24 CT Scan Angiography

25 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

26 Ultrasound Image (echo) produced when different neighboring tissues reflect different acoustic impedances Solid organs, fat, & stones: Echogenic (white) Fluid & cysts: Anechoic (black)

27 Ultrasound

28 Advantages 1.No ionizing radiation 2.Applicable to any plane 3.Cost-effective 4.Portable 5.Real-time imaging Disadvantages 1.Time consuming 2. Poorer quality

29 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

30 MRI Advantages vs CT: 1.Multiplanar scanning 2.Better soft-tissue differentiation 3.Contrast-free 3DMR Contraindications: Metals, clips, pacemakers

31 MRI T1T2

32 Normal CXR

33 Normal CXR

34 Enlarged Hila

35 Hilar Mass (Left) Aortic Knob

36 Right vs Left Pulmonary Artery

37 Kerley B-Lines Fine horizontal opacified lines representing pulmonary edema Seen in CHF, pulmonary fibrosis, heavy metal fibrosis, malignancy

38 Blunted Costophrenic Angle

39 Lung Mass: Cavitation

40 Lung Mass: Solid Tissue

41 Air Space (Alveolar) Disease

42 Interstitial Disease

43 Alveolar or Interstitial?



46 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




50 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



53 Where Is This Consolidation?

54 Diaphragm Gastric Bubble

55 Diaphragm: Expiration vs Inspiration

56 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

57 Pleural Effusion: Large

58 Pleural Effusion: Small

59 Pleural Effusion: Small (special case)


61 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

62 Pneumothorax Optimal Radiographic Images: 1.Expiration film 2. Lateral decubitus film

63 Pneumothorax


65 Subtle Pneumothorax

66 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

67 Pulmonary Embolism

68 With Infarction: 1. Hamptons Hump

69 Pulmonary Embolism Perfusion Test (Q) Technetium-99 Ventilation Test (V) Xenon gas Further Diagnostics Perfusion/Ventilation mismatch, V/Q Mismatch

70 Pulmonary Embolism V/Q Scan Interpretation 1.Normal Perfusion scan =Rules out PE 2.Negative/Low Probability scan (slight perfusion abnormality or V/Q matching)= Non-embolic pulmonary abnormalities 3.Positive/High Probability= V/Q mismatch 4.Intermediate/Indeterminate = Low & High Pulmonary Angiogram indicated for 3, 4, or 2 with strong clinical evidence

71 Pulmonary Angiogram Gold Standard

72 Helical (Spiral) CT Scan Indicated for suspected PE with abnormal CXR CT venogram: Adding IV contrast for concurrent deep leg vein scan

73 References hilum.html las/cxratlas_f.htm las/hilar.htm las/apwindow1.htm las/normallabeled.htm m med/med3/2003/ddi/matdid/cap2.htm

74 References med/med3/2003/ddi/matdid/cap1.htm ON_LATERAL_SEGMENT_RML.jpg 4.html hr.htm nar/images/effusion.jpg l.html

75 References g 18-F2.jpg Prob.html 3.RT-Angio.gif adenoma-ct-scan.html

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