Title: Potential role of FDG PET in the setting of diabetic neuro-osteoarthropathy: can it differentiate uncomplicated Charcot’s neuroarthropathy from osteomyelitis and soft tissue infection?
Authors: Sandip Basu, Timothy Chryssikos, Mohammed Houseni, D. Scot Malay, Jagruti Shah, Hongming Zhuang and Abass Alavi
Source: Nuclear Medicine Communications. 2007,28:465-472.
PODIATRIC RELEVANCE:
Podiatric physicians treating complications of the diabetic foot must face the diagnostic challenge of differentiating Charcot’s neuroarthropathy from infectious pathological processes. Until now, no single imaging test has been able to provide a definitive diagnosis. Magnetic resonance imaging (MRI) has been proven unreliable in distinguishing osteomyelitis from marrow edema associated with other non-infectious entities. This article presents the potential use of fluorodeoxyglucose (FDG) positron emission tomography (PET) in the setting of complicated clinical decision-making issues.
METHODS:
In this prospective study, a total of 63 subjects divided into four groups were evaluated: (A) 17 patients with a clinical diagnosis of Charcot’s neuroarthropathy, (B) 21 patients with uncomplicated diabetic foot, (C) 20 non-diabetic patients with normal lower extremity as control, and (D) 5 diabetic patients with proven osteomyelitis. Each subject underwent bilateral FDG PET imaging and MRI of the foot. The images obtained were independently examined by two groups of physicians blinded to the radiographical data and final diagnosis. The FDG PET images were qualitatively analyzed and maximum standard uptake value (SUVmax) in areas of the foot with abnormally increased uptake were determined. In subjects without focal disease, the SUVmax was calculated from the mid-foot region. FDG PET findings were then compared to MRI results.
RESULTS:
The authors observed that Charcot’s joints showed a low-grade diffuse FDG uptake that was clearly distinguishable from the normal joints. The SUVmax varied from 0.7 to 2.4 in Charcot’s lesions, from 0.2 to 0.7 in the normal control subjects, from 0.2 to 0.8 in uncomplicated diabetic foot, and from 2.9 to 6.2 in foci of osteomyelitis. They demonstrated that the overall sensitivity and accuracy of FDG PET in the diagnosis of Charcot’s foot was 100 and 93.8%, respectively, compared to the corresponding values of 76.9 and 75% for MRI. Additionally, FDG PET showed enhancement in the soft tissue suggesting inflammation in seven patients (43.75%) where as only two of these patients showed signs of soft tissue involvement on the MRI.
COMMENTS:
FDG PET is a new technology that may be valuable for podiatric physicians in diagnosing and efficiently treating diabetic patients with complicated clinical presentation. This imaging modality is not currently available in all medical centers but could optimize the management and outcome of numerous patients.
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Disclaimer:
Scientific Abstract Monthly postings are submitted by podiatric surgical residents. The ideas presented are not the opinions of the American College of Foot and Ankle Surgeons (ACFAS), nor are they presented as facts. ACFAS presents this information without any warranty of any kind, expressed or implied, and is not liable for its accuracy nor for any loss or damage caused by the user's reliance on information obtained in these areas.