PMC4533472_01
Magnetic resonance imaging on admission. Fluid attenuated inversion recovery image (A) and diffusion-weighted image (B) showed a high intensity area in the right maxillary sinus, bilateral ethmoidal sinus, and right paratentorial and parafalcine subdural space.
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F1
Magnetic resonance (MR) images revealed a high signal lesion on a diffusion-weighted image (DWI) and fluid attenuated inversion recovery (FLAIR) images in the right paratentorial and parafalcine subdural space, right maxillary sinus, and bilateral ethmoidal sinus (Fig. 1).
Operative findings of the initial surgery. A: With right occipital craniotomy, pus (arrow) was evacuated from the right falcotentorial subdural space. B: After placing subdural drainage, the wound was closed with the bone flap removed.
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F2
The patient was diagnosed with subdural empyema and underwent emergent surgery for empyema removal and decompression (Fig. 2).
MRI after initial surgery. A, B: MRI the day after surgery (A: upper: FLAIR, lower: DWI, B: Gd-T1WI). Subdural empyema along the occipital falx and cerebellar tentorium was well removed, but empyema along the frontal falx remained. C, D: MRI on the 6th day postoperatively (C: upper: FLAIR, lower: DWI, D: Gd-T1WI). Empyema in the frontal to parietal parafalcine area had increased. DWI: diffusion-weighted image, FLAIR: fluid attenuated inversion recovery, Gd-T1WI: gadolinium-enhanced T1-weighted image, MRI: magnetic resonance imaging.
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F3
Follow-up magnetic resonance imaging (MRI) 6 days after surgery demonstrated an increase of empyema in the fronto-parietal area (Fig. 3), and the patient complained of aggravated headache.
Operative findings of the second surgery. A: With right fronto-parietal craniotomy, pus (arrow) was evacuated from the subdural space along the falx. B: After placing subdural drainage, the wound was closed with the bone flap removed.
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F4
Right frontoparietal craniotomy was performed with the patient in the supine position (Fig. 4).
Magnetic resonance imaging after second surgery (A: FLAIR, B: DWI). Subdural empyema along the falx was removed, but it remained in the right frontal and tentorial space. High intensity on FLAIR emerged in the right temporal lobe. DWI: diffusion-weighted image, FLAIR: fluid attenuated inversion recovery.
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F5
Most of the subdural empyema along the falx was removed (Fig. 5). A week after the second surgery, CT demonstrated a low density area in the right temporal and lobe, which showed high intensity on MRI FLAIR images and iso intensity on DWI (Fig. 5).
Magnetic resonance imaging 2 months after discharge (A: FLAIR, B: DWI). High intensity areas on FLAIR and DWI had disappeared. DWI: diffusion-weighted image, FLAIR: fluid attenuated inversion recovery.
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F6
The FLAIR high intensity lesion had completely disappeared on MRI 2 months after discharge (Fig. 6).