The application of transcranial Doppler sonography in patients with chronic subdural haematoma

The aim of this study was to evaluate the haemodynamic changes of the middle cerebral artery (MCA) and their clinical significance before and after surgical aspiration in patients with chronic subdural haematoma (CSDH). Nineteen patients with CSDH (17 unilateral and 2 bilateral) received transcranial Doppler sonography (TCD) examinations for cerebral blood flow velocity (CBFv) of the MCA prior to and 5 days after neurosurgical treatment. A total of 21 lesion and 10 non-lesion hemispheres were included. Cranial computerized tomography (CT) and clinical assessments were performed before and 3 months following surgery. The preoperative TCD study revealed that the lesion hemisphere had a modest decrease in CBFv in the MCA as compared to the non-lesion hemisphere. Postoperatively, the CBFv significantly improved in the lesion hemisphere, but not in the non-lesion hemisphere, compared to the preoperative data (P < 0.005). The improvement in CBFv showed no significant correlation with brain shift and haematoma volume of the initial cranial CT. Additionally, two patients, who were proved to have a postoperative complication of subdural pneumocephalus, failed to attend follow-up examinations of TCD. Our results support TCD as an alternative follow-up examination for patients with CSDH, although it may not be sensitive enough as a preoperative screening tool. Postoperatively, improvements in the CBFv of the lesion hemisphere are characteristic. An unexplained difficulty of accessing cerebral basal arteries in follow-up TCD examinations should suggest pneumocephalus in the primary differential diagnosis.