Cath Lab Digest

   Similar to using SPECT scans, one can combine the FDG-PET scan with CT scans to further improve accuracy and spatial resolution to verify the exact anatomic location of bone infection.³⁵ Although more research is necessary, FDG-PET scans are becoming an acceptable, accurate alternative for diagnosing osteomyelitis.

   Neutropenia, peripheral vascular disease and chronic kidney disease are comorbidities associated with diabetes mellitus that limit the effectiveness and value of nuclear medicine imaging.²³ With respect to white blood cell labeled SPECT/CT, the in-vitro process employed not only takes time and effort to perform, but also may delay diagnosis.²⁷ Furthermore, the additional use of CT exposes patients to larger amounts of radiation than other imaging modalities.³⁶

   Certain limitations also exist when considering FDG-PET as an imaging modality. The pre-examination checklist for patients to receive FDG-PET scans is meticulous. Preparation involves strict N.P.O. (except water) four to six hours before examination, avoidance of rigorous activity before and after injection of the radioisotope to minimize muscular uptake by FDG, and strict glycemic control.²³ Research has shown the presence of hyperglycemia to reduce the uptake of FDG, which significantly diminishes imaging resolution and diagnostic efficacy.²⁶ Ideal blood glucose levels prior to FDG-PET imaging are less than or equal to 150 mg/dL. Financial costs and restricted availability also limit the application or consideration of SPECT or PET scans in today’s clinical and hospital settings.³¹

   As emerging research continues to explore the capability of these modalities in the accurate diagnosis of osteomyelitis, the paradigm may ultimately change in favor of nuclear medicine. This is largely due to the fact that nuclear medicine continues to establish the ability to both diagnose and differentiate osteomyelitis from other similarly presenting pedal diseases, largely Charcot neuroarthropathy.

Key Pearls On Antibiotic Treatment

One can approach the treatment of osteomyelitis with a variety of different therapy options. Throughout the years, the standard treatment options have included debridement of all necrotic and non-viable bone and soft tissue with an adjunct of antimicrobial therapy.^37-38 More severe cases of osteomyelitis may warrant amputation of the affected digit or limb. It is vital to ensure one has eradicated all remaining infection from the site.

   The current recommendations are that during surgical debridement, one should obtain cultures of the soft tissue and drainage in order to better select specific antibiotic therapy and an appropriate dose.³⁸ Oral and parenteral therapies can achieve similar cure rates, but oral therapies are less expensive and avoid the risks associated with intravenous catheters.³⁸

   Recently, there has been more discussion regarding the use of oral antibiotics as well as the duration of treatment. Spellberg and Lipsky revealed there is no hardcore evidence proving that antibiotic therapy for four to six weeks improves the overall outcome in comparison to shorter treatment regimens.³⁷ One deciding factor in the efficacy of the medication is based on the antibiotic’s ability to penetrate bone. Each antibiotic has a specific ability to permeate bone and this can be greatly decreased in patients with vasculopathy and other peripheral vascular disorders.³⁹