Posted: November 19th, 2022

Radiology – Ankle MRI

RADIOLOGY – MRI

Read the article ( I’ll attache it ) https://www.acr.org/~/media/ACR/Documents/PGTS/guidelines/MRI_Ankle_and_Hindfoot.pdf on ankle (and hindfoot) MRI from the American College of Radiology and answer the questions below according to the article.

These require short answers only. 

ASSIGNMENT QUESTIONS:

Question 1 

With respect to disorders of the ankle, MRI is a proven imaging modality for what?

Question 2 

Results of ankle MRI can be misleading if there is no correlation with?

Question 3 

Provide a list of at least 10 primary indications for performing ankle MRI.

Question 4 

List some clinically diagnosed conditions that may (or may not) have been supported by other imaging modalities for which MRI may be indicated for clarification or staging.

Question 5 

What clinical scenarios might ankle MRI be useful to investigate?

Question 6 

What are some advantages and disadvantages to plantarflexion of the ankle for MRI?

Question 7 

What determines the necessary field of view FOV? Give examples.

Question 8 

What slice thickness and interslice gap variations are suggested?

Question 9 

In bullet point form or in a table list the ideal MRI sequences used to scan the ankle and why/what pathologies do they best demonstrate?

Q1: With respect to disorders of the ankle, MRI is a proven imaging modality for what?
• Detection
• Assessment
• Staging
• Follow-up
Q2: Results of ankle MRI can be misleading if there is no correlation with?
Radiographs, clinical history, physical examination physiologic test (for example nerve conduction analysis and electromyography), and other imaging studies.
Q3: Provide a list of at least 10 primary indications for performing ankle MRI.
The indications include, but are not limited to, diagnosis, exclusion, and grading of the following suspected disorders:
• Congenital and developmental conditions: dysplasia, tarsal condition, and symptomatic and asymptomatic variants.
• Infections of bone, joint or soft tissue.
• Neoplasms of bone, joint or soft tissue.
• Sinus tarsi syndrome
• Neurologic conditions such as nerve entrapment and compression, denervation neuropathy, including tarsal tunnel syndrome.
• Peroneal tendon disorders: partial and incomplete tears, tendinitis, tendinopathy, sublaxation, tenosynovitis, dislocation, and abnormalities of the peroneal retinaculum
• Impingement syndromes: anterolateral, anteromedial, posterior, and posteromedial.
• Osteochondral abnormalities, articular cartilage abnormalities, and intra-articular bodies, degenerative or traumatic.
• Plantar fasciitis, plantar fascia rupture, and plantar fibromatosis
• Achilles tendon disorders: partial and complete tears, tendinitis, tendinopathy, treated tears, paratenonitis, and xanthomas.
Q4: List some clinically diagnosed conditions that may (or may not) have been supported by other imaging modalities for which MRI may be indicated for clarification or staging.
• Arthritides: inflammatory, infectious, neuropathic, degenerative, crystal-induced, and post-traumatic.
• Rimary and secondary bone and soft tissue tumors
• Fractures and stress factors.
Q5: What clinical scenarios might ankle MRI be useful to investigate?
• Limited or painful range of motion
• Ankle or subtalar instability
• Unexplained ankle or hindfoot swelling, mass, or atrophy
• Patients for whom diagnostic or therapeutic arthroscopy is planned
• Prolonged, refractory, or unexplained ankle or heel pain
• Acute ankle trauma
• Ankle and/or hindfoot malalignments
• Patients with recurrent, residual, or new symptoms following ankle surgery
• Ankle and hindfoot injuries in athletes
• Patients or relatives with familial hypercholesterolemia or hyperlipidemia
Q6: What are some advantages and disadvantages to plantar flexion of the ankle for MRI?
Advantages:
• Reorients the medial and lateral ankle tendons so that a single imaging plane will show a larger length of each in cross-section and so that a smaller segment of each tendon will pass through the magic angle.
• Plantar flexion eliminates aliasing which degrades mage quality.
Disadvantages:
• It may render visualization of the ankle ligaments more difficult.
• It may make it harder to include the entire Achilles tendon in the FOV.
Q7: What determines the necessary field of view FOV? Give examples.
The size of the anatomic structures under consideration and the suspected pathology.
For example: visualization of the entire extent of a large Achilles tendon tear may require a 22cm FOV of 12 cm or smaller in the sagittal plane, although a FOV of 12 cm or smaller in the coronal plane may be needed.
Q8: What slice thickness and inter-slice gap variations are suggested?
Slice thickness: 4mm or less
Inter-slice gap variations: Maximum of 10% of the slice width.
Q9: In bullet point form or in a table list the ideal MRI sequences used to scan the ankle and why/what pathologies do they best demonstrate?
MRI sequence. Pathologies best demonstrated.
T2-weighted • Ankle and hind foot ligaments.
• They are important to compensate for magic angle artefact seen in tendons.
T1-weighted • Detection of various stages of haemorrhage and muscle disorders as well as tendon infiltration.
• May also be used in case there is suspicion of PVNS (pigmented villonodular synovitis)

References
American College of Radiology. (2016). Practice parameter for the performance and the interpretation of magnetic resonance imaging (MRI) of the ankle and hindfoot.

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Tags: Radiology - Ankle MRI