The relationship between cerebral blood flow velocities and the amount of blood clots in computed tomography after subarachnoid haemorrhage

127 patients with aneurysmal subarachnoid haemorrhage (SAH) were analyzed f or the relationship between the amount of blood clots as detected by initia l computed tomography (CT) up to 48 hours after SAH and changes of blood fl ow velocities as measured using transcranial Doppler ultrasonography (TCD). All patients were operated on within 72 hours after SAH. Patients who pres ented with remarkable brain oedema or with pathological intracranial pressu re (ICP) due to mass effects of a haematoma, and who were in a poor neurolo gical condition classified according to Hunt-Hess as grade V were excluded from this study. Serial TCD examination of the middle cerebral arteries (MC A) and anterior cerebral arteries (ACA) started within 48 hours after SAH a nd were performed dairy up to three weeks. A statistically significant corr elation between blood load designated according to Fisher's grading as grou p CT I-CT IV and mean flow Velocities (MFV) was found in groups CT I, IT, a nd III. High values of MFV in MCA examinations were noted in patients with severe SAH (group CT III)- 161 cm/s, and low values in patients without SAH (group CT I)- 119 cm/s. Patients with haematocephalus and/or haematoma wit hout a mass effect (group CT IV) had lower blood how velocities than patien ts with severe SAH (group CT III) but values were higher than in patients w ithout SAH (group CT I). The number of days for which MFV in the MCA was > 120 cm/s and was statistically (p < 0,05) correlated with the amount of blo od clots as observed in the respective CT (in group CT I, II, and III). MFV values in the anterior cerebral artery (ACA) were lower than those obtaine d in the middle cerebral artery (MCA) in all groups. Statistically signific ant (p < 0,05) differences were noted between groups CT I and CT III (first and third week) and between groups CT I and CT IV (third meek). If the SAH was extensive in the CT scan, pathological values of MFV > 90 cm/s were ob served in ACA, and this was more pronounced in group CT III than in group C T IV. Blood flow Velocities obtained via TCD were registered to compare sid e-to-side differences and particularly high differences were observed in pa tients with severe SAH. It is concluded that the amout of blood clots in the initial computed tomog raphy after SAH is significantly correlated with cerebral blood flow veloci ty measurements by TCD.