Search Pattern - XR MSK
1. Do you have the right study open?
- Are you looking at the right patient? Always confirm patient identity with two constant identifiers (name, MRN, DOB).
- Never use room number for patient identity.
- Are you looking at the most current exam? Confirm the date and time of exam that you're viewing.
2. Is the study technique adequate?
Use the RIPE-F acronym, but without the I
- Rotation - is the patient rotated left or right? For example, a rotated lateral knee will make it hard to look for a suprapatellar joint effusion
- Inspiration - not relevant
- Projection - AP, PA, lateral radiographs are the most common.
- Exposure - actually related to the radiology physics concept of penetration. Are portions of the bone too white, obscuring trabeculations? If so, the study is underpenetrated. Are portions of the bone too black to see bony anatomy? If so, the study is overpenetrated. This occasionally happens with fingers and elsewhere.
- Field of view - adequate field of view requires the image to include the relevant bony anatomy for the study type. Rather than listing this out, you'll get used to this from the studies you see on rotation.
3. Is there any pathology?
Use the BJS acronym🌟, not the other 🗑 variations out there.
B. Bones
Skeletal maturity - immature = ossification centers or growth plates. Otherwise, mature. Take a moment to identify the ossification centers and growth plates to avoid getting distracted by them later when you're looking for fractures.
Mineralization - osteopenia = slightly darker, with more prominent trabeculations. Otherwise, normal.
Fractures - direct signs (lucent lines), indirect signs (elevated fat pads, lipohemarthroses)
Lytic lesions - bone looks eaten-away, like metastatic renal cell carcinoma.
Sclerotic lesions - small or large bone lesions that look white. These could be bone islands (benign) or metastatic disease. Compare with remote priors for stability, or get a bone scan to diagnose bone islands.
J. Joints
Alignment - In the elbow, use the radoiocapitallar line (reliable across all projections and obliquities) and the anterior humeral line (less reliable).
Degenerative change - Look for joint space narrowing, subchondral sclerosis, osteophytes. These findings are associated with use, more pronounced in athletes, obesity, and older age.
Erosions - eaten-away appearance of bone within or adjacent to the joint. These findings are associated with gout, rheumatoid arthritis, psoriatic arthritis, and juvenile inflammatory arthritis.
Effusions - fluid accumulating in the joint, particularly important in the elbow and knee. In the elbow, look for elevated fat pads that indirectly represent a joint effusion. In the knee, look for an oval grey opacity in the suprapatellar space on lateral knee radiograph that represents the suprapatellar joint effusion. Ankle joint effusions are similar to the knee, but harder to see on radiograph.
S. Soft Tissue
Foreign bodies - glass is slightly more opaque than soft tissue, but not as much as metal, so you'll need to search carefully for the geometric shapes like triangles, rectangles, and trapezoids that represent shards of glass.
Calcifications - Vascular calcifications follow the course of arteries, more commonly seen in diabetes and older patients. Soft tissue calcifications are typically more discrete and round, also more common in older patients.
Air - air looks like pockets or tracks of black areas in the subcutaneous tissue or muscle. Consider necrotizing fasciitis in the setting of infection, and alert the surgeon immediately. You may also see small amounts of soft tissue air immediately after abrasions, stab wounds, and fractures.
Masses - masses look very similar to muscle on radiograph, so the round contours of the mass as they displace fat planes or muscle is what you're looking for, not just the absolute opacity of the mass. Sometimes radiographs can be useful to look for possible bony changes associated with a mass like a tumor, even though ultrasound, CT, and MRI are more useful to characterize the mass itself.