Decubitus Ulcers

Preliminary Diagnosis: Decubitus Ulcers

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

MRI

II. Describe the advantages and disadvantages of this technique for diagnosing decubitus ulcers.

Advantages

• Can rule out complications of decubitus ulcers, such as osteomyelitis, fluid collections, abscesses, and sinus tract

• Does not require use of ionizing radiation and may be performed in pregnant patients

Disadvantages

• Expensive

• Requires a significant amount of patient cooperation due to long imaging times

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?

• Plain radiograph

• Nuclear medicine

• Computed tomography

• Ultrasound

V. Describe the advantages and disadvantages of the alternative techniques for diagnosing decubitus ulcers.

Plain radiograph

Advantages

• Relatively quick imaging procedure that requires minimal patient cooperation

• Inexpensive

• Recommended as the initial imaging technique to evaluate osteomyelitis associated with decubitus ulcers; radiography and MRI are complementary, and both are indicated

Disadvantages

• Exposure to ionizing radiation

• May be normal in early osteomyelitis

Nuclear medicine

Advantages

• Can be used if MRI is contraindicated

• The 3-phase bone scan has a high sensitivity for osteomyelitis

• An alternative nuclear imaging technique is the ¹¹¹In-labeled white blood cell scan

Disadvantages

• Weak anatomic analysis

• Relatively expensive

• Radiation risks due to administered radionuclide

• 3-phase bone scan loses specificity in the setting of recent trauma or surgery, as either of these will mimic osteomyelitis

• ¹¹¹In-labeled white blood cell scan has a poor image resolution and often fails to distinguish whether the infection is in bone, soft tissue, or both

Computed tomography

Advantages

May be useful in patients who have a contraindication to MRI

Disadvantages

Exposure to ionizing radiation

Ultrasound

Advantages

• Noninvasive

• Inexpensive

• Does not use ionizing radiation

• Can assess associated soft tissue abnormalities, such as cellulitis, soft tissue abscesses, and acute septic arthritis

Disadvantages

• Operator dependent

• A patient with acute tenderness at the site of suspected infection may not be able to tolerate the ultrasonic probe touching the surface

• Limited bone evaluation

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

Plain radiograph

Pregnancy is a relative contraindication. The small risk must be weighed against the benefit.

Nuclear medicine

Contraindicated in pregnant women and those who are breastfeeding

Computed tomography

Contraindicated in pregnant women, especially during the first two trimesters

Ultrasound

No contraindications