ACL Tear

Images of What a Musculoskeletal Radiologist Sees

So what do some common major conditions look like to a radiologist? First let me explain who we are and what we do. Musculoskeletal radiologists have a medical degree, general radiology training and usually fellowship specialty training. My particular training started with an MD from Columbia University, then a residency in diagnostic radiology at Baptist Memorial Hospital in Memphis and finally a fellowship in musculoskeletal radiology at UC San Diego. I do many types of diagnostic work, including sports injury imaging, tumors, arthritis, infections, and bone diseases. Other physicians will often order studies or we will make those decisions in conference. Basically, you see your doctor with a sore knee or shoulder, and he or she will direct you to ARA where a musculoskeletal radiologist will be carefully interpreting your scan while bringing his or her full diagnostic skills to bear on your problem. Then your physician will review our imaging report in coordination with your overall care.

Image 1 - ACL Tear Our first image is an MRI of the knee viewed from the side. We are looking on the left at a healthy anterior cruciate ligament (ACL). The right side shows the ACL when it’s completely torn. This is the infamous “ACL tear” you will hear announced during a sports event and know that the athlete is destined for surgery and sideline recovery time. The ACL is essential in normal knee stability and is most often torn when the knee joint is hyperextended, twisted, or both. This image shows a complete tear, but partial tears can also occur.

Image 2 - Osteoid Osteoma Our second image is a benign bone tumor called an osteoid osteoma. You can see the tumor in the red circle and, as small as it is, it is causing a lot of surrounding issues. In particular, you can see the edema visible in the bone marrow on the MRI as whitish signal, but you can see a better view of the actual tumor in the CT on the right as a bright focus in the center of the red circle. This is a very painful condition, more common in young people, but very treatable and benign.

Image 3 - Plantar Rupture 3 The third image shows a torn plantaris tendon – a very dramatic and painful injury. In this picture, there is fluid signal between muscles in the calf where the plantaris tendon is typically located.

Image 5 - Parsonage Turner Syndrome 2 The next image is a classic example of Parsonage Turner Syndrome—a painful condition related to abnormal nerve innervation to specific muscles of the shoulder which can also produce weakness and numbness.  The cause is often unknown but can be seen following surgery, infection, trauma, or even after a vaccination. In the above set of MRI images of the shoulder, there is bright signal in the supraspinatus and infraspinatus muscles—classic for Parsonage Turner Syndrome.

People sometimes want to know how radiologists decide which studies to recommend. In the case of musculoskeletal radiology, we tailor the imaging study to the specific question or injury of concern.  Sometimes, the best test is an MRI, other times CT scan,  ultrasound, or bone scan.  Even a standard x-ray can be the test of choice.  It all depends on the individual patient and his or her specific needs.

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