Dynamic contrast-enhanced MRI parameters and apparent diffusion coefficient as treatment response markers of skull base osteomyelitis: a preliminary study

Purpose:
Currently, there is no definitive consensus on the optimal imaging modality for determining the treatment response in patients with skull base osteomyelitis (SBO). This study aimed to investigate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters and apparent diffusion coefficient (ADC) as treatment response markers of SBO.

Material and methods:
This study included 6 patients with SBO, who underwent both pre- and post-treatment DCE-MRI and diffusion-weighted imaging (DWI). Quantitative DCE-MRI parameters and ADC of the region-of-interest were analysed. These normalized parameters were calculated by dividing the region-of-interest by the reference region. The Wilcoxon signed rank test was used to compare these parameters between pre- and post-treatment periods.

Results:
The normalized fraction of the extravascular extracellular space (V_e) and ADC of the post-treatment status of SBO was significantly lower than those of pre-treatment measures (p = 0.03). The normalized fraction of blood plasma (V_p), normalized rate of transfer from the blood plasma into the extravascular extracellular space (K_trans), and normalized backflow leakage of material from the extravascular extracellular space into the blood plasma (K_ep) demonstrated no significant differences between pre- and post-treatment.

Conclusions:
DCE-MRI parameters V_e and ADC demonstrated a significant reduction when comparing measures across the pre- and post-treatment periods. These parameters may potentially serve as a valuable surrogate treatment response marker for SBO activity.