Week 3: Extremity

Question 1

Advantages of musculoskeletal CT

Answer 1

• Display of cross-sectional
• Ability to compare both sides
• Display bone & soft tissue simultaneously
• Excellent contrast sensitivity
• Ability to construct MPR or 3D reformats

Question 2

CT cystography

Answer 2

• Axial, Coronal, Sagittal multi-planar evaluation of bladder
• nearly 100% accurate at detecting bladder wall perforations if bladder full enough

Question 3

CT Wrist

Answer 3

• pt position: head first, prone, arm over head
• internal laser light: mid forearm
• coronal laser: mid coronal plane of wrist
• sagittal laser: as close as possible to wrist
• start location: just proximal to distal radio ulnar joint
• end location: at proximal metacarpals

Question 3

CT Arthrography

Answer 3

• To evaluate joints using contrast and/or air.
• It is useful for evaluating joint capsule & intracapsular structures
• For finding loose bodies within joints

Question 4

CT Elbow

Answer 4

• pt position: prone, head first, affected arm over head and extended, arm oblique OR pt supine arm at side
• start: just above elbow joint
• end: below radial tuberosity

Question 5

CT Shoulder

Answer 5

• pt position: pt supine, head first, affected arm at side opposite arm above head
• internal laser: typhoid process
• coronal laser: mid coronal plane
• sagittal laser: mid sagittal plane or shift to get affected side as close to isocenter if possible
• start: just above AC joint
• end: just below scapular tip

Question 6

CT Knee

Answer 6

• pt position: supine, feet first, tape feet together
• internal laser: 2 inches above patella
• coronal laser: at midcornal plane
• sagittal laser: mid sagittal plane or shift to get affected knee closer to iso centre if possible
• start: just above patella
• end: just below fibular head

Question 7

CT Hip

Answer 7

• pt position: supine, legs flat on table (no sponge), feet first
• internal laser: top of iliac crest
• coronal laser: mid coronal plane
• sagittal laser: mid sagittal plane
• start: just above SI joints
• end: 4 cm below lesser trochanters (include entire fracture if present)

Question 8

CT Ankle

Answer 8

• pt position: supine, legs flat on table, use foot holder or tape feet together
• start: just above tibial plafond (just above ankle joint)
• end: just below calcaneus