18F FDG PET-CT three-dimensional tool for localizing the exact location of the infected bone

Osteomyelitis is a challenge in diagnosis and treatment. 18F-FDG PET-CT provides a non-invasive tool for diagnosing and localizing osteomyelitis with a sensitivity reaching 94% and specificity reaching 100%.

Ahmed Elsheikh et al conducted a study to assess the agreement in identifying the geographic area of infected bone and planned resection on plain X-ray versus 18F-FDG PET-CT. The study has been published in 'Indian Journal of Orthopaedics.'

Clinical photos and X-rays of ten osteomyelitis patients were shown to ten consultant surgeons; they were asked to draw the area of infection and extent of planned surgical debridement; data will be compared to 18F-FDG PET-CT results. The authors tested the agreement between the surgeons in every parameter.

Key findings of the study:

•The median years of experience of the included surgeons were three years and ranged from 1.5 to 6 years.

•The median annual infected cases treated by any surgeon were 28 (range 5 to 100 cases).

•The most common preferred tool for diagnosis was X-ray and CT together (50%).

•MRI was requested in 20% of cases, while the least frequent modality was CT alone (10%).

•The median circularity reading was significantly lower in X-ray (0.5) than 18F-FDG PET-CT (0.67) (p < 0.001).

•There was no correlation between any parameter and the years of experience ( p >0.05) nor the number of cases per year (p>0.05).

•Regarding height, there was poor agreement between surgeons.

•Regarding perimeter, the ten surgeons showed low-moderate agreement.

•The ten surgeons showed a low moderate agreement for circularity.

•Results document the variability of assessment and judgement based on plain X-rays.

•In comparison to PET-CT, All parameters were significantly different in favour of 18F-FDG PET-CT over X-ray (P<0.001).

The authors concluded that – "18F FDG PET-CT provides a three-dimensional tool for localizing the exact location of the infected bone and differentiating it from the normal bone. Thus, it could be beneficial in precise pre-operative planning and surgical debridement of chronic osteomyelitis."

Further reading:

Role of 18F FDG PET CT in Pre Operative Planning of Surgical Debridement in Chronic Osteomyelitis. Ahmed Elsheikh, Mostafa Elazazy et al Indian Journal of Orthopaedics (2022) 56:2237–2244https://doi.org/10.1007/s43465-022-00771-9