MRI of brain with T1 weighted echo train spin echo, T2 weighted
 echo train spin echo, T2 weighted fluid-attenuated inversion
 recovery echo train spin echo, MR diffusion imaging, chemical shift
 MR imaging with metabolite map, and with intravenous gadolinium-
 enhancement:

1. Small amount long T1 and T2 crescent fluid accumulation in left
   frontoparietal subdural space without restricted water
   diffusibility (figure 1 and red arrow in figure 2), but with
   small short T1 and T2 structures content (yellow arrows in
   figure 3-5), in favor of subdural effusion with some blood clots of
   extracellular methemoglobin, nature to be determined.
2. Presence of patchy thickening of left pachymeninges with
   some contrast enhancement (green arrows in figure 3-5, more
   obvious on post-Gd T2WI FLAIR images than post-Gd T1WI images),
   and gadolinium diffusion/leakage into left subdural space (blue
   arrows in figure 3-5), possibly associated with increased membrane
   permeability of meninges.
3. Small right subdural effusion (white arrow in figure 2) with mild
   patchy thickening of right pachymeninges with some contrast
   enhancement.
4. No evidence of leptomeningeal enhancement.
5. Relative thinning of corpus callosum (figure 6), predominant over
   body and splenium, callosal hypogenesis can not be excluded.
6. Enlarged subarachnoid spaces without ventricular enlargement,
   suggesting external hydrocephalus (benign enlargement of the
   subarachnoid space).
7. No abnormal finding in remaining brain.
   No detectable abnormal metabolism.

Impression:
1. Bilateral subdural effusion with increased permeability of left
   meninges and some blood clots within left subdural effusion.
2. Corpus callosum hypogenesis.