Pes Anserine Bursitis

Preliminary Diagnosis: Pes Anserine Bursitis

Pes Anserine Bursitis

I. What imaging technique is first-line for this diagnosis?

• MRI

II. Describe the advantages and disadvantages of this technique for diagnosis of pes anserine bursitis.

Advantages

• Able to detect other causes of pain or weakness in the joint such as tendonitis, tenosynovitis, or tears of the tendons of the pes anserinus (sartorius, gracilis and semimembranosus)

• Exclude connection to medial meniscus and joint effusion with good certainty

• Does not make use of any ionizing radiation

Disadvantages

• Expensive

• Time consuming.

• Requires significant patient cooperation to minimize motion artifact

• Intravenous contrast requires that the patient have good renal function with a GFR greater than 60. Administration of intravenous contrast is decided individually on a case by case basis with a GFR greater than 30 and less than 60

III. What are the contraindications for the first-line imaging technique?

• Contraindicated in patients with non–MR-compatible metallic hardware or foreign bodies

IV. What alternative imaging techniques are available?

• Ultrasound

• CT with or without contrast

V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of pes anserine bursitis.

Ultrasound

Advantages

• Able to detect fluid collection and whether fluid is simple or complex.

• Optimal modality for concomitant detection and aspiration of fluid if indicated

• Relatively inexpensive

• Portable imaging modality

• Does not use ionizing radiation

Disadvantages

• Requires a skilled technician trained in musculoskeletal imaging with a high index of suspicion for detection of pathology

• Limited evaluation in obese patients

CT with or without contrast

Advantages

• Able to see fluid-filled bursa in its typical location

• Further detail of bone if fracture or osseous lesions suspected

• Performed much more quickly than MR imaging

• Requires less patient cooperation and is associated with less motion artifact than MR imaging

Disadvantages

• Soft tissue structures and tendons better evaluated with MRI

• Exposes the patient to a large amount of ionizing radiation

• Imaging with intravenous contrast requires that the patient have good renal function with a creatinine of 0.6-1.2 mg/dL for an adult

VI. What are the contraindications for the alternative imaging techniques?

Ultrasound

• No significant contraindications exist

CT with or without contrast

• Contraindicated in a pregnant patient, especially within the first two trimesters

• Relative contraindication in patients with a contrast allergy

• Relative contraindication in patients with renal failure