Oftentimes "osteomyelitis" can be diagnosed based on the clinical appearance alone. However, frequently indications are not clear. In acute cases, radiological changes in conventional X-ray imagery are very subtle and only detectable after 2 to 3 weeks. In chronic cases, the distinction between healed and active forms is very difficult.
Computed tomography (CT) and magnetic resonance imaging (MRI) play an increasingly important role in the diagnosis of osteomyelitis. CT or MRI can help identify necrotic bone mass and are essential when planning surgical rehabilitation. MRI also helps to distinguish between infection of the bone and surrounding tissue.
Nuclear medicine studies – such as bone scintigraphy (Tc-99m) – are used as search methods in osteomyelitis. However, this method is not very specific, as enrichment can be found for any increased (even non-infectious) activity in the bone. Use of labeled anti-granulocyte antibodies in addition can increase the specificity.
A definitive diagnosis, however, can only be made through detection of the causative microorganisms. Usually an attempt is made to grow the bacteria from swabs, aspirates or other tissue samples in a special culture medium. Even so, this effort does not always prove successful, as only free-living planktonic bacteria are cultivable. If the pathogen at the time of sampling is only existent in its sessile form, i.e. in biofilms, the culture remains false negative (more on this: Culture Negative Orthopedic Biofilm Infections).
By means of a suitable ultrasonic treatment ("sonication"), the causative agent can be released from the biofilm, thereby increasing the accuracy. This new method is applied routinely at Döbling Osteitis Center.
In the end, a reliable diagnosis can only be made by an experienced specialist, after evaluating all available evidence.