Orthopedic Radiology Lecture Powerpoint Flashcards
3 most common imaging modalities in orthopedics
- radiographs (xray)
- MRI
- CT
X rays (radiographs)
Best for imaging bony structures, differentiates well between bone (white), soft tissue (grey), and air (black), 2D in nature so often have to get multiple films to get a better view of structure, full eval should always include joint above and below, indicated in deformity of bone or joint or suspicion of fracture, or pain/inability to use the extremity. Children and pregnant women need shielding to minimize radiation exposure
Maisonneuve fracture
Fracture of proximal fibula near the head (around knee) associated with a distal tibial fracture (ankle) based on the interosseous membrane that runs between these that pulls on the proximal fibula, emphasizes importance of evaluating joint above and below when imaging to not miss things like this
Periosteum
Dense connective tissue sheath around the bone where osteoblasts develop, can become thickened (reactive) when injured, elevated in bone irritation/inflammation, or disrupted in a fracture
Epiphysis vs physis vs metaphysis vs diaphysis
Caps on the end of bone proximal and distal, growth plate, transition of bone into body (flare), body shaft of compact cortical bone
Sail sign/posterior fatpad sign
Suggestive of occult fracture of the proximal radius based on x ray finding where we see subcutaneous tissue being pushed off the soft tissue due to swelling of pooling blood
Arthrogram definition and 2 risk factors with performance
Injection directly into joint capsule often under ultrasound guidance, often the shoulder, of contrast dye that is then taken under x ray for analysis of leakage, less costly than CT or MRI, does have increased risk of infection or allergic rxn
MRI
Imaging study with advantage of seeing soft tissue details, can identify minor tumors excellent for imaging of spine (disc herniation, nerve compression) or joints (esp. associated torn ligaments and tendons or occult stress fractures), can be combined with contrast materials, might be indicated for preoperative planning or sorting out diagnostic dilemmas (generally not first line unless suspected neurological/soft tissue involvement)
MRI contraindications (2)
- Metallic foreign body presence in welders, shrapnel, implants, etc
- claustrophobic patients (sedation or anxiolytic might be needed)
CT scans
Imaging study that offers visualization of bone, muscle, and fat, bone is excellently visualized but soft tissue less so, indicated in preoperative planning for bony fractures, or complex fracture patterns with fractures involving articular surfaces, also often used in patients with degenerative spine disease
CT scans risks/contraindications (2)
- high doses of radiation
- pregnancy
Bone scan
Nuclear medicine study useful for displaying blood flow and metabolic activity of bone thru injection of IV radioisotope and study of its distribution, indicated in identifying infections, tumors, or occult fractures (all places where there is increased metabolic activity)
Knee dislocations always require what radiologic study?
Angiography
Torus/buckle fracture
Fracture most often seen in children where the periosteum is elevated due to bone irritation/inflammation from a fracture of the bone that has not extended out past the periosteum, leaving it completely in place
Fracture callus
Repair that bridges the proximal and distal bone in a healthy healing bone
