What is the shoulder pad sign and what does it have to do with this case?

This is a 52-year-old with a swollen shoulder. What is the shoulder pad sign? What’s your diagnosis for this case?

Coronal water-weighted

The shoulder pad sign is associated with clinical shoulder swelling bilaterally in amyloid arthropathy of the shoulders. This is not amyloid. It is synovial chondromatosis of the subdeltoid bursa. There are primary and secondary varieties. The secondary type usually occurs with chronic inflammation of osteoarthritis. The primary type most likely results from a mutation, and, unlike the secondary type, may dedifferentiate into a malignant chondrosarcoma on rare occasions.

Synovial chondromatosis is one of the synovial metaplasias. The others include:

  • Synovial osteochondromatosis
  • Villonodular synovitis
    • Focal
    • Diffuse
  • Pigmented villonodular synovitis
    • Focal (also called focal giant cell tumor of tendon sheath)
    • Diffuse
  • Lipoma arborescens
  • Synovial hemangiomatosis

For more shoulder case review, head to MRI Online.

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How serious is this patient’s post-replacement knee pain?

This 69-year-old presents with knee pain post knee replacement. There is bone loss. Is it aggressive or non-aggressive?

Bone window setting CT coronal reformat

Bone window setting CT sagittal reformat

Bone window setting sagittal CT reformat

No, this is not aggressive. Posterior zone of transition is too sharp and a little sclerotic (green arrows). There is osteolysis from metal prosthesis with dense material (orange arrow) in the suprapatellar pouch, e.g. particulate disease, metallosis and/or ALVAL aseptic lymphovascular associated lesion. MR often shows metallosis better than CT. For more knee case review, check out MRI Online.

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What should you be looking for in this baseball player’s elbow injury?

This 21-year-old has sharp pain (worse with movement) and weakness after a baseball injury. Evaluate contusion. What’s the mechanism of injury?

MRI coronal T2 SPIR

MRI coronal T2 SPIR

Pure valgus insult leads to proximal ulnar collateral ligament tear (arrow) and fracture with hyperintense edema of the radius. Your next move should be to evaluate the rest of the study and exclude an elbow dislocation. In this case, there was none. Your valgus injury checklist should include inspection of:

  1. Proximal aspect anterior bundle of UCL (aUCL)
  2. Sublime tubercle distal insertion of aUCL
  3. Ulnar nerve
  4. Medial epicondyle or apophysis
  5. Aponeurotic layer of flexor digitorum superficialis muscle
  6. Radial head
  7. Capitellum
  8. Olecanon fossa spurring or edema

For more case review, check out MRI Online.

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You recognize the wrist lesion, but what is its typical location?

This is a 15-year-old female with a dorsal soft tissue mass. You are shown two images, a short-axis T1-weighted spin echo (image 1) and a short-axis T2-weighted spin echo image (image 2).

There really is not a differential diagnosis. So a more challenging question is: where does such a lesion normally occur in the wrist?

Short axis T1-weighted spin echo

Short axis T2-weighted spin echo


The diagnosis is Ganglion pseudocyst. It is true that the signal intensity of a cystic schwannoma, myxoma and epidermoid could be similar but all of these diagnoses are implausible in a 15-year-old. In generating a report, none of these should really be proposed. The most common locus for ganglion pseudocyst in the wrist is directly atop or dorsal to the scapholunate capsule (paired arrows). The ganglion is highlighted with single arrows.

The second most common location is the palmar aspect of the scapholunate capsule and region of the radioscaphocapitate ligament. While these lesions can be decompressed with a needle or by slamming them with a book (a little bit unpleasant) they often recur and require resection with repair of the deficient capsule. For those of you with a religious bent, a heavy bible can be used to smash these. For those of you with a political bent, you can try smashing it with a copy of the U.S. Constitution.

Check out MRI Online for more case review.

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Guess the sport for this 30-year-old with knee pain

This 30-year-old male presents with knee pain after a motor vehicle accident. But his imaging should have you immediately thinking about his athletic background. Which two sports stand out as his likely hobbies? Bonus points if you know a position in one of the sports that seems to see this injury even more frequently.

Sagittal PD

Sagittal PD


This man likely plays volleyball and / or basketball. He has “jumper’s knee” (arrows on sagittal MRI) or infrapatellar tendinopathy with retropatellar swelling. Middle blockers in volleyball are especially prone to this abnormality.

For more knee case review, check out MRI Online.

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Why I took antibiotics and my tendon screamed!

This 80-year-old female presents with lower left leg soft tissue swelling and limb pain for three months. She also has a history of Levaquin therapy. What two ruptures must you take note of in her imaging?

Axial T2

Axial T2

Coronal non-contrast

Axial non-contrast

Axial post-contrast

This patient has a plantaris rupture (yellow arrow, image one) and an achilles rupture (orange arrow, image two), both related to her history of Levaquin therapy. A short-segment DVT within the peroneal vein is demonstrated on the green arrows in images 1,3, 4, 5. This fails to enhance, as shown on image five, where a “delta” sign is present. There are other medications noted to affect tendons and include flouroquinolones producing tendon degeneration or rupture. The groups includes Levaquin, Cipro, Avelox, Floxin, Maxaquin and Noroxin. Diseases that notoriously infiltrate tendons include:

  • SLE
  • Gout
  • CPPD
  • Amyloid

So, this patient has DVT, plantaris tear and Achilles tear. Wow! For more case review, head to MRI Online.

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Do you see the unusual finding in this adolescent’s patella?

This 17-year-old male has patellar pain in his right knee. The cause of his pain is somewhat unusual. What is the most common locale of patellofemoral osteochondritis dissecans? What is the best treatment in a juvenile? What is the underlying cause?

Sagittal T2

Coronal STIR

Sagittal T1

Sagittal T2

Axial T2


The unusual finding is stage 2 osteochondritis dissecans (OCD). Take note of the approximately 12 x 5 x 9mm area of the patella just deep to the articular surface surrounded by thin linear hypointensity (arrow, image 5) suggesting fibrous attachment. A “puffy” appearance to the lesion (image 5) suggests a blister has formed in the overlying cartilage. There is no evidence of dislodgement at this time.

The most common location of patellofemoral OCD is the anterolateral femoral trochlear ridge. The best treatment in a juvenile is rest, especially if the growth plates are open. Most will heal. Sometimes lateral retinacular release is effective. The underlying cause of OCD is most likely repetitive friction microtrauma from an underlying femoral or patellofemoral dysplasia that devitalizes the superficial capsular blood supply to the bone.

For more knee case review, head to MRI Online.

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Why is this 18-year-old having foot pain?

This 18-year-old female presents with a palpable soft tissue mass subjacent to the first metatarsophalangeal (MP) joint that she has noticed for 1-2 months. It is painful with shoes and ambulation, and you are evaluating her for a soft tissue tumor. What is the cause of her problem, and what pertinent negatives must you notice?

Axial T2

Axial T1

Axial PD fat-sat

Sagittal T1

Sagittal GRE

Coronal T2

This patient has a so-called “pressure lesion” due to ambulation, with associated adventitial bursa/pseudobursa formation within. It is a chronic process. This is manifested as a large, ovoid mass-like structure within the subcutaneous soft tissues along the plantar aspect of the first MP joint and sesamoid bones (arrow). It is well-circumscribed and demonstrates a mildly lobulated configuration. There is peripheral signal hypointensity indicating a rim or rind of fibrosis, and there is intermediate to high T2 signal centrally, suggesting a component of complex fluid. The major differential diagnosis is fibroma of tendon sheath. This is a counterintuitive diagnosis as fibrous lesions are typically dark on all pulsing sequences. But, fluid signal from the tendon sheath may be found in this specific fibrous tumor. So, fibromas of tendon sheath are typically hyperintense centrally.

While the lobulation of the lesion medially is reminiscent of plantar fibromatosis, the constellation of findings remains most compatible with a giant pressure lesion. Fibromatosis (non-aggressive type) occurs more proximally in the middle aponeurotic cord of the plantar fascia. The findings are not suspicious of an aggressive neoplastic lesion (based on location and concentric shape), and you can also rule out MP joint capsulitis and Morton’s neuroma because of location. You should always rule out plantar plate tear along the second MP joint on thin section sagittals if you have a large pressure lesion under the second metatarsal head. For more case review, visit MRI Online.

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Can you make the diagnosis for this 65-year-old jaundice patient?

This patient is a 65-year-old with jaundice. You are initially shown one axial T2 spin-echo image (fig. 1, with fig. 1A provided for closer look at findings) with two green arrows pointing to what sign? To what sign is its single purple arrow pointing? Then you are shown an MR cholangiopancreatography (MRCP, w/ yellow arrow, fig. 2) and an axial T2-weighted image (w/ blue arrow, fig. 3). After seeing these two additional images, what is your diagnosis?

The green paired arrows in the first image point to the double duct sign (fig. 1A) of pancreatic carcinoma. The single purple arrow in the same image indicates a Courvoisier gallbladder from pancreatic obstruction. The MRCP (fig. 2) shows obstruction of the pancreatic and biliary ducts, both intra- and extrahepatic. The side branch clubbing of the pancreatic ducts indicated with the yellow arrow (fig. 2) is consistent with prior bouts of pancreatitis. The horizontal blue arrow (fig. 3) shows a swollen or enlarged pancreatic head and uncinate process. All of these factors combine to produce a diagnosis of pancreatic carcinoma. For more case review, check out MRI Online.

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What abnormality (that often produces a labral tear) is seen in this patient?

The three axial oblique images in this 43-year-old with hip pain demonstrate an abnormality. What are the associated potential imaging findings that might accompany this abnormality?

Axial oblique fat-suppressed GRE

The lack of tapering of the femur head to the neck is known as asphericity. This lack of tapering is associated with a bump in the anterior aspect of the femoral head neck junction. The bump is also associated with a friction-related pseudocyst (“herniation pit”) that occurs when the hip is in flexion and especially in flexion-internal rotation as this area rubs across the acetabulum. Sometimes the friction produces edema but not an actual cyst.

  • In such a patient, the alpha angle (if measured) would be elevated.
  • An abrasion, ulcer or erosion would often be seen in the far anterior superior acetabulum as this bump rides against and abrades or erodes the cartilage of the acetabular roof.
  • Some patients with this abnormality may have a shallow acetabular cup.
  • Labral tears and detachments are frequent.
  • Capsular rents or tears may occur.

Clinically, such patients often experience pain in hip flexion worse in internal more than external rotation. This case illustrates an axial oblique head neck junction shape of Cam or Type 1 hip impingement syndrome. For more case review, check out MRI Online.

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