Musculoskeletal #26

Describe the abnormality

Bilateral sacroiliac joint space narrowing, subchondral erosions, subchondral sclerosis, and subchondral fatty marrow infiltration.

What is the differential diagnosis?

Bilateral symmetrical:
Ankylosing spondylitis
Inflammatory bowel disease. 

Bilateral asymmetrical:
Psoriasis
Reactive arthritis (Reiter syndrome) 

What is the most likely diagnosis?

Ankylosing spondylitis

What are the markers of active inflammation?

Erosions with high signal intensity on STIR or T2- weighted images, subchondral edema, and enhancement within or adjacent to the sacroiliac joint.

What are the markers of chronic disease?

Low signal intensity on T1- and T2- weighted images, subchondral sclerosis, narrowing of the joint spaces, bone bridging, and ankylosis.

Emergency #35

61-year-old female:
– Trauma
– Fracture? What do you see?

Showing the supine AP and lateral view, due to the inability to stand on the right leg.

Click here to see the answer

Diagnosis: Lipohemarthrosis (fat-blood level) indicating intra-articular #
Comminutive though non-displaced tibia plateau fracture Avulsion fracture proximal fibula (Segond fracture – 100% association with ACL injury)
CT: Schatzker type VI

Schatzker tibia plateau classification

Schatzker I: wedge-shaped pure cleavage fracture of the lateral tibial plateau, having less than 4 mm of depression or displacement
Schatzker II: splitting and depression of the lateral tibial plateau; namely, type I fracture with a depressed component
Schatzker III: pure depression of the lateral tibial plateau; divided into two subtypes:
Schatzker IIIa: with lateral depression
Schatzker IIIb: with central depression
Schatzker IV:  medial tibial plateau fracture with a split or depressed component
Schatzker V: wedge fracture of both lateral and medial tibial plateau
Schatzker VI: transverse tibial metadiaphyseal fracture, along with any type of tibial plateau fracture (metaphyseal-diaphyseal discontinuity)

Musculoskeletal #24

48-year-old male:
– Heavy smoker
– Depressive syndrome

Found lying unconscious at home, in lateral position (opioid overdose)
Erythema and limited movement of the left shoulder
Blood test: CK 7949 u/l. Negative blood and aspiration cultures (no infection)

What do you see?

Findings

CT: Low attenuation area involving the posterior aspect of the deltoid muscle and the lateral aspect of the pectoralis major muscle. Superficial and deep fascia edema. No enhancing walls neither gas is seen.

MRI: Postcontrast T1FS images show hypointense unenhancing central muscle fibers surrounded by thick rim enhancement involving the posterior deltoid, teres minor, and pectoralis major muscles . Thickened and hyperenhancing adjacent fascia and reactive muscle edema are also noted.

What is the most likely diagnosis?

Rhabdomyolysis (type 2: myonecrosis)
– Injury to skeletal muscle that involves leakage of large quantities of potentially toxic substances into plasma.
– Type 1: homogeneous signal changes and contrast enhancement. Ischemic or reversible ischemic reaction.
– Type 2: homogeneous or heterogeneous signal changes and rim enhancement. Irreversible muscular necrosis (myonecrosis).

– Deep tissue injury: severe pressure ulcer, characterized by necrotic tissue mass under intact skin.

– CK > 1000 – 5000 iu/l “cut-off”.

– Risk factors: postoperative patients (position), obesity, male gender, diabetes, surgical bleeding…

Musculoskeletal #22

What do you see?

Click here to see the answer

Vertebral hemangioma with thickened trabeculae and fat foci inside the lesion, without soft tissue component with an associated pathological fracture.

TEACHING POINTS:
Bone hemangiomas are very frequent, atypical presentations and complications (like in this cases with soft tissue component and pathological fracture) are rare but radiologist must be aware of them to be able to make the correct diagnosis.

Musculoskeletal #20

72-year-old alcoholic patient with intractable dorsal pain and legs numbness and weakness.

What do you see?

Click here to see the answer

IMAGING FINDINGS:

Thoracic spine compression fracture with posterior displacement of the posterior wall of the vertebral body compromising the spinal canal, cord compression and associated myelopathy. T2W image shows fluid and hypointense bubble-like artifact consistent with vacuum cleft in the collapsed anterior vertebral body

DIAGNOSIS:

Kümmel disease (osteonecrosis and collapse of the vertebral body)

TEACHING POINTS:

Intravertebral vacuum cleft and fluid within the collapsed vertebral body is a characteristic feature
Differential diagnosis includes a pathologic (tumoral) fracture, and the presence of air strongly favors osteonecrosis

Would you like to see a complementary case?

Click here


MR T2-weighted and CT images to highlight the characteristic features of Kümmel disease

Intravertebral fluid seen on T2 image and air on CT image

Emergency #26 – Flashcard

A 30-year-old female with right shoulder pain.

4 images of the right shoulder were obtained (axillar, Y-view, internal rotation, external rotation)

Click here to see the images
Y-view

Internal rotation
External rotation
Findings:

Findings


Right shoulder: There is a nondisplaced fracture involving the inferior aspect of the glenoid, with involvement of the articular surface. Glenohumeral joint shows normal alignment. Acromioclavicular joint is normal. No soft-tissue calcification. No fracture or dislocation

What is the most likely diagnosis?

The most likely diagnosis is Hill-Sachs lesion

Hill-Sachs lesions are a posterolateral humeral head compression fracture. Typically occurs secondary to recurrent anterior shoulder dislocations. It is often associated with a Bankart lesion of the glenoid

Internal Rotation
External Rotation

These lesions are best seen following relocation of the joint. It appears as a sclerotic line running vertically from the top of the humeral head towards the shaft. A wedge defect may be evident in large lesions. The lesions are better appreciated on internal rotation views

Musculoskeletal #15 – Flashcard

This is the third and last case of the musculoskeletal series. Check the first one and second one on this blog.

What do you see on the following images?

Click here to see the answer

Osteoblastoma: Osteoblastoma is histologically similar to osteoid osteoma but they are larger (usually accepted more than 1 cm), often involving the posterior column

Musculoskeletal #12 – Flashcard

43-year-old healthy patient:
– with fibromyalgia
– No other relevant medical history

What do you see on the following images?

Click here to see the answer

IMAGING FINDINGS:

Multiple focal sclerotic bone lesions clustered around joints in both knees and sacroiliac joints

DIAGNOSIS:

Osteopoikilosis

TEACHING POINTS:

Sclerosing bony dysplasia characterized by multiple enostoses
Typically clustered around joints, aligned parallel to trabeculae. Usually 1-3 mm, they can reach up to 20 mm
Rare condition; inherited; asymptomatic; incidental
Important to avoid misdiagnosis with other relevant pathologies such as metastasis

Musculoskeletal #11

68-year-old male:
* Presents with a mass around knee which has been present for seven years and has been enlarging since then

What do you see?

A sclerotic ill-defined soft tissue mass around the knee was present on radiographs.
The mass is located in the soft tissue around the knee with no apparent bone destruction.

Coronal fat-suppressed T2 WI (a) shows a hyperintense lobulated mass which was hypointense on T1 WI (b) and has peripheral heterogeneous enhancement on postcontrast T1 WI (c); cortical bone is preserved.

The mass encircles a pedunculated lesion which continues with cortical and medullary bone (arrows), consistent with an osteochondroma.
Histopathologic diagnosis of the mass is chondrosarcoma.

Osteochondromas

* Osteochondromas are developmental lesions rather than true neoplasms and are often referred to as an osteocartilaginous exostosis (or simply exostosis).
* An osteochondroma is composed of cortical and medullary bone protruding from and continuous with the underlying bone; cortical and medullary continuity between the osteochondroma and parent bone is well depicted on MRI.
* Malignant transformation, almost invariably due to chondrosarcoma arising in the cartilage cap of the lesion, occurs in approximately 1% of solitary osteochondromas.
* Lesions that grow or cause pain after skeletal maturity should be suspected of malignant transformation since osteochondromas only rarely enlarge after this time.