Upper Extremity Imaging By Prof. J. Stelmark. Exposure Factors The principal exposure factors for...

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Transcript of Upper Extremity Imaging By Prof. J. Stelmark. Exposure Factors The principal exposure factors for...

  • Slide 1
  • Upper Extremity Imaging By Prof. J. Stelmark
  • Slide 2
  • Exposure Factors The principal exposure factors for radiography of the upper limbs are as follows: 1. Lower to medium kV (50 to 70) 2. Short exposure time 3. Small focal spot 4. Adequate mAs for sufficient density
  • Slide 3
  • 1. Phalanges (fingers and thumb)14 2. Metacarpals (palm)5 3. Carpals (wrist)8 TOTAL27 HAND AND WRIST
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  • A.First carpometacarpal joint of right hand B.First metacarpal of right hand C.First metacarpophalangeal joint of right hand D.Proximal phalanx of first digit (or thumb) of right hand E.Interphalangeal joint of first digit (or thumb) of right hand F.Distal phalanx of first digit (or thumb) of right hand G.Second metacarpophalangeal joint of right hand H.Proximal phalanx of second digit of right hand I.Proximal interphalangeal joint of second digit of right hand J.Middle phalanx of second digit of right hand K.Distal interphalangeal joint of second digit of right hand L.Distal phalanx of second digit of right hand M.Middle phalanx of fourth digit of right hand N.Distal interphalangeal joint of fifth digit of right hand O.Proximal phalanx of third digit of right hand P.Fifth metacarpophalangeal joint of right hand Q.Fourth metacarpal of right hand R.Fifth carpometacarpal joint of right hand
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  • WRIST The wrist has eight carpal bones, which are fitted closely together and arranged in two horizontal rows. The carpals are classified as short bones and are composed largely of cancellous tissue with an outer layer of compact bony tissue. The proximal row of carpals, which is nearest the forearm, contains the scaphoid, lunate, triquetrum, and pisiform. The distal row includes the trapezium, trapezoid, capitate, and hamate.
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  • Carpals (Wrist) The third group of bones of the hand and wrist are the carpals, the bones of the wrist Right carpals (dorsal or posterior view)
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  • Right carpals (palmar or anterior view)
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  • A.Scaphoid B.Lunate C.Triquetrum D.Pisiform E.Trapezium F.Trapezoid G.Capitate H.Hamate h.Hamulus (hamular process of hamate) PA wrist
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  • WRIST JOINT MOVEMENT TERMINOLOGY Certain terminology involving movements of the wrist joint may be confusing but must be understood by technologists because special projections of the wrist are described by these movements. The ulnar deviation movement of the wrist opens up and best demonstrates the carpals on the opposite side (the radial or lateral side) of the wrist, namely, the scaphoid, trapezium, and trapezoid. Because the scaphoid is the most frequently fractured carpal bone, this ulnar deviation projection is commonly known as a special scaphoid projection. Radial deviation: A less frequent PA wrist projection involves the radial deviation movement that opens and best demonstrates the carpals on the opposite, or ulnar side, of the wrist, namely, the hamate, pisiform, triquetrum, and lunate.
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  • PA, OBL, and LAT PROJECTION: FINGERS Pathology Demonstrated Fractures and/or dislocations of the distal, middle, and proximal phalanges; distal metacarpal; and associated joints are demonstrated. Some pathologic processes, such as osteoporosis and osteoarthritis, also may be demonstrated.
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  • Central ray: CR , centered to PIP joint SID: 100110 cm (4044) Position Patient seated at end of table, elbow flexed 90 (lead shield over lap) Pronate hand, separate fingers Center and align long axis of affected finger(s) to portion of IR being exposed
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  • Position Patient seated, hand on table, elbow flexed 90 (lead shield over lap) Align fingers to long axis of portion of IR being exposed Rotate hand 45, resting against 45 angle support block Separate fingers; ensure that affected finger(s) is (are) parallel to IR
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  • Position Patient seated, hand on table (lead shield over lap) Hand in lateral position, thumb side up for 3rd5th digits, thumb side down for 2nd digit Align finger to long axis of portion of IR being exposed
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  • Central ray: CR , centered to lst MP joint
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  • Position Patient seated, hand on table, elbow flexed Align thumb to long axis of portion of IR being exposed With hand pronated, abduct thumb slightly. This position tends to naturally rotate thumb into 45 oblique.
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  • Position Patient seated, hand on table, elbow Align thumb to long axis of portion of IR being exposed With hand pronated and slightly arched, rotate hand medially until thumb is in true lateral position
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  • Position Patient seated, hand on table, elbow flexed Align long axis of hand and wrist parallel to edge of IR Hand fully pronated, digits slightly separated Central ray: CR , centered to 3rd MCP joint
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  • Rotate entire hand and wrist laterally 45, support with wedge or step block. Align hand and wrist to IR. Ensure that all digits are slightly separated and parallel to IR
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  • for possible foreign body and metacarpal injury
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  • Position Patient seated, arm on table Align hand and wrist parallel to edge of IR Lower shoulder, rest arm on table to ensure no rotation of wrist Hand pronated, fingers flexed, and hand arched slightly to place wrist in direct contact with surface of IR Central ray: CR , centered to midcarpals
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  • Rotate hand and wrist into 45 oblique position Flex fingers to support hand in this position, or use 45 support block
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  • A.Scaphoid B.Lunate C.Triquetrum D.Pisiform E.Trapezium F.Trapezoid G.Capitate H.Hamate h.Hamulus (hamular process of hamate) Ulnar deviation
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  • Scaphoid views: CR angle with ulnar deviation Warning: If patient has possible wrist trauma, do not attempt this position before routine wrist series has been completed and evaluated to rule out possible fracture of distal forearm and/or wrist. Pathology Demonstrated Fractures of the scaphoid are demonstrated. Non-displaced fractures may require additional projections or a CT scan of the wrist.
  • Slide 29
  • Mechanics of scaphoid fracture: The scaphoid is the most commonly fractured carpal bone. One reason for this is its location among the other carpal bones. Two rows of carpal bones exist, a distal row and a proximal row, with joint spaces between them that allow the wrist to flex. The long scaphoid bone, however, is aligned partially with both of these rows with no joint space. When an individual falls on an outstretched hand the wrist is hyperextended, causing the proximal and distal carpal rows to flex at the joints, and a great deal of stress is placed on the narrow waist of the scaphoid. This stress may result in a fracture.
  • Slide 30
  • Technical Factors IR size18 24 cm (8 10 inches) Division in half, crosswise Detail screen, tabletop Digital IRuse lead masking 60 6 kV range
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  • Shielding Place lead shield over patient's lap to shield gonads. Patient Position Seat patient at end of table, with wrist and hand on cassette, palm down, and shoulder, elbow, and wrist on same horizontal plane.
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  • Part Position Position wrist as for a PA projectionpalm down and hand and wrist aligned with center of long axis of portion of IR being exposed, with scaphoid centered to CR. Without moving forearm, gently evert hand (move toward ulnar side) as far as patient can tolerate without lifting or rotating distal forearm
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  • Angle CR 10to 15proximally, along long axis of forearm and toward elbow. (CR angle should be perpendicular to long axis of scaphoid.)
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  • To demonstrate the scaphoid without foreshortening, position the patient's wrist in maximum ulnar deviation; then direct a 15-degree proximal (toward the elbow) central ray angulation to the long axis of the scaphoid.
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  • Center CR to scaphoid. (Locate scaphoid at a point 2 cm [ inch] distal and medial to radial styloid process.) Minimum SID is 40 inches (100 cm).
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  • Collimation Collimate on four sides to carpal region Exposure Criteria: Optimal density and contrast with no motion visualize the scaphoid borders and clear, sharp bony trabecular markings.
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  • PA SCAPHOIDHAND ELEVATED AND ULNAR DEVIATION: WRIST Modified Stecher Method Warning: If patient has possible wrist trauma, do not attempt this position before routine wrist series has been completed and evaluated to rule out possible fracture of distal forearm and/or wrist.
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  • PA wrist for scaphoid: Hand elevated 20 Ulnar deviation if possible No CR angle
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  • Severe pain: Hand elevated 20 No ulnar deviation No CR angle
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  • Slide 41
  • Shielding Place lead shield over lap to shield gonads. Patient Position Seat patient at end of table, with elbow flexed and resting on table, wrist and hand on cassette, and palm down, with