Below are some general principles to follow when ordering musculoskeletal imaging studies:
- Obtaining plain films initially is helpful to evaluate pain, even if internal derangement is suspected.
- MRI for soft tissues, internal derangement, occult fracture, bone marrow.
- MRI arthrogram to rule out labrum tear in the hip or shoulder and to evaluate triangular fibrocartilage complex (TFCC), scapholunate ligament or lunatotriquetral ligament in the wrist.
- If MRI is contrainidicated, such as for a patient with a pacemaker, CT arthrography is the next best test for internal derangement (cuff tear, meniscal tear, ligament tear). You can also substitute an MRI arthrogram for labrum and TFCC.
- Ultrasound for problem solving and nonradio-opaque foreign body.
- It is acceptable to state “contrast per radiologist discretion” when ordering MRI and CT. However, please indicate CT arthrogram or MRI arthrogram when intra-articular contrast is desired as additional planning and scheduling is required at imaging. Arthrograms require different additional planning and scheduling than for just the contrast used for an MRI or CT.
- When in doubt, please do not hesitate to call one of our subspecialized musculoskeletal radiologists at 310-423-5724.
When do I order an MRI arthrogram?
An MRI arthrogram is used to rule out a labrum tear in the hip or shoulder, and to evaluate triangular fibrocartilage complex (TFCC), the scapholunate ligament or the lunatotriquetral ligament in the wrist.
When do I order a CT arthrogram?
A CT arthrogram is used for:
- To rule out a meniscus tear in the knee
- To rule out a rotator cuff tear or labral tear in the shoulder
- To rule out a TFCC tear, scapholunate ligament tear or a lunatotriquetral ligament tear in the wrist
If you just need to rule out an occult fracture, order a noncontrast CT.
What if there is a contraindication to MRI, such as a pacemaker?
If an MRI cannot be done, a CT arthrogram can be performed (see rotator cuff tear).
- Labral tear (MRI arthrogram, not MRI with contrast)
- Rotator cuff tear (MRI or, if contraindicated, CT arthrogram)
- SLAP - labrum tear (MRI arthrogram)
- Hip and groin pain: rule out labral tear (fluoroscopy)
- Sacroiliac joint injection (CT)
- Undiagnosed sacroiliitis (CT)
- Ankle pain (X-ray, MRI, CT)
If you have any questions, please do not hesitate to call to consult one of our musculoskeletal radiologists at 310-423-5720.
The S. Mark Taper Foundation Imaging Center provides a full range of advanced imaging, both radiology and cardiology, as well as interventional radiology and interventional tumor (oncology) treatments to the greater Los Angeles area, including Beverly Hills, Encino, Mid-Cities, Sherman Oaks, Silver Lake, Studio City, Toluca Lake and West Hollywood.