Imaging in osteomyelitis

Technique	Advantages	Disadvantages	Sn/Sp	Main Findings
X-ray	Inexpensive	Late diagnosis	43 to 75%/75 to 83%	Lytic lesions, osteopenia, periosteal thickening, loss of trabecular architecture, new bone apposition
	Reproducible	Confusing
	Accessible	Radiation
CT	Excellent spatial resolution	Cost	67%/50% (chronic)	Blurring of fat planes
		Availability		Increased density of fatty marrow
		Radiation exposure		Periosteal reaction
				Cortical erosion or destruction
				Sequestra, involucra, intraosseous gas
US	Accessibility, inexpensive, real-time evaluation	Operator dependent	To be determined	Elevated periosteum
	Guided aspiration-biopsy	US beam cannot cross cortical bone		Soft tissue abscess
				Fluid collection
MRI	Excellent spatial resolution	Cost	82 to 100%/75 to 96%	Acute
	Early detection	Availability		T1-weighted: low-signal-intensity medullary space
	Assessment of the extent of tissue affected	Time requested		T2-weighted: high signal intensity surrounding inflammatory processes, edema
				Gadolinium: enhances areas of necrosis
				Subacute
				Evidence of Brodie's abscess, single or multiple radiolucent abscesses
				T1-weighted: central abscess cavity with low signal intensity
				T2-weighted: high signal intensity of granulation tissue surrounded by low-signal-intensity band of bone sclerosis (double-line effect)
				Chronic
				T1- and T2-weighted: low-signal-intensity areas of devascularized fibrotic scarring in the marrow
Bone scan	Sensitive	Nonspecific	~85%/~25%	Focal hyperperfusion
	Availability	Further imaging evaluation required		Focal hyperemia
	Relatively inexpensive			Focal bone uptake
	Early detection
Bone+WBC scan	Reliable when clearly positive or negative	Need for two isotopes with multiple imaging sessions over several days	~60%/~80%	Localized area of increased uptake
		High radiation exposure
		Large number of equivocal results
		Long examination time

Further Reading

• Pineda C, Espinosa R, Pena A. Radiographic Imaging in Osteomyelitis: The Role of Plain Radiography, Computed Tomography, Ultrasonography, Magnetic Resonance Imaging, and Scintigraphy. Semin Plast Surg. 2009;23(2):080-089.