Imaging findings
The most commonly involved sinuses, defined as opacification of the sinus cavity, were the frontal (n=33, 84%) and ethmoid (n=25, 64%) (Table 2). The most common intracranial complications were SDE (n=25, 64%) and EDA (n=12, 31%). Five patients had more than one simultaneous collection. Frontal bone osteomyelitis was found in three patients. Median time from admission to CT and MRI was six hours (range 2-58) and 15 hours (range 4-70) respectively. In eight patients MRI demonstrated an intracranial collection not detected by the CT alone.