There is a large R sided extra axial haematoma with associated midline shift. The increased density in the middle of the haematoma indicates new haemorrhage. This indicates it is in fact an acute-on-chronic bleed. Despite the biconvex shape, this is a <strong>subdural haemorrhage</strong>, since the haematoma crosses the suture lines of the skull.
Pre-existing cerebral atrophy has allowed the patient to tolerate this degree of midline shift. Her new L sided weakness likely reflects the newer onset bleed, which has exhausted her cerebral tolerance & resulted in climbing intracranial pressures.
Skeptics will think this is more likely to be an extra-dural haematoma, due to the biconvex shape. However, EDHs do not cross suture lines, while subdural haematomas can cross them. SDHs most commonly form concave layer over the brain, but can be almost any shape. An EDH would be extremely rare for this patient: she is over 60yrs old (the dura becomes more adherent to the skull with age); atraumatic EDH is a very rare occurance.