• 
• 

Three Part Question

In a [diabetic patient] with a [deep infected foot wound] does [MRI or plain radiography have a better clinical utility for diagnosig osteomyelitis?]

Clinical Scenario

A 58 year old male patient with long standing diabetes mellitus and peripheral neuropathy presented to the emergency department after having noticed a deep wound to the plantar aspect of his left foot. You suspect osteomyelitis and wonder what would be the most appropriate imaging modality- plain radiograph or MRI.

Search Strategy

Medline from 1950 to June 2007 through the ovid interface and Embase from 1996 to week 25 2007
(exp diabetes mellitus OR exp diabetic neuropathies OR exp diabetic foot) AND (exp osteomyelitis) AND (exp magnetic resonance imaging OR MRI.mp. OR exp x-ray OR plain radiograph.mp.) LIMIT to humans AND English language

Search Outcome

The search located 69 papers, 2 of which were relevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Capriotti G, Chianelli M, Signore A. 2006 Italy	57 papers (50 original research articles and 7 reviews) that described the imaging of the diabetic foot and examined a total of 2889 lesions.	meta-analysis	MRI and x-rays efficacy in the diagnosis of osteomyelitis	In the diagnosis of osteomyelitis MRI has a sensitivity of 90.1% (x-ray 61.9.5) a specificity of 73.9% (x-ray 67.5%) an accuracy of 80.5% (x-ray 65.6) a positive predictive value of 87.3% (x-ray 71.3%) and a negative predictive value of 85.7% (x-ray58.5%)
Kapoor A, Page S, LaValley M, Gale DR, Felson DT. 2007 USA	496 patients from 16 studies into the diagnostic performance of different imaging techniques in osteomyelitis. At least one site with the disease and one without were identified by the gold reference standard (e.g. bone biopsy)	meta-analysis	DOR and specificity of MRI and x-ray for the detection of osteomyelitis	The diagnostic odds ratio for MRI was 42.1% and the specificity (at a 90% cut point) was 82.5%. This is consistently better than for plain radiography (81.5 vs 3.3)	Although the authors mention that the studies were evaluated for inclusion (and the inclusion criteria) the paper does not mention what sort of studies were included or their validity.

Comment(s)

Both papers found were large, well conducted meta-analysis of the data and agree that MRI has a markedly better diagnostic performance than x-ray at detecting osteomyelitis.

Clinical Bottom Line

In patients with suspected osteomyelitis MR Imaging is a better tool for diagnosis than x-ray.

References

1. Capriotti G, Chianelli M, Signore A. Nuclear medicine imaging of diabetic foot infection: results of meta-analysis Nuclear Medicine Communications 2006;27:757-64
2. Kapoor A, Page S, LaValley M, Gale DR, Felson DT. Magnetic Resonance Imaging for Diagnosing Foot osteomyelitis. Arch Intern Med 2007;167:125-32