Transcranial Doppler (TCD) was carried out to determine the resistive index (RI) values of normal canine cerebral arteries and its reproducibility and to evaluate the change of cerebral vascular resistance following diuretics administration. RI values of rostral cerebral artery (RCA) were compared between fontanelle window and temporal window. Normal ranges and reproducibility of the RI values were examined in the rostal cerebral artery (RCA) and caudal cerebral artery (CCA). And after administration of diuretics, TCD-derived RI values were measured at RCA and CCA. Cerebral vascular RI values of RCA and CCA were 0.55 +/- 0.05 and 0.55 +/- 0.03 in the normal dogs, respectively. There was no significant difference of RI between male and female; between fontanelle window and temporal window. Reproducibility of RI measurements between intraobserver and interobserver were relatively high. The RI of RCA and CCA were significantly increased 15 minutes after mannitol administration (p<0.01) and returned to baseline values by 30 minutes, but it did not significantly change after furosemide and saline administration. The results suggest that TCD is a useful test which can obtain reproducible results from any window and has the advantage of detecting subtle changes in cerebral vascular resistance.
Animals ; Cerebral Arteries/drug effects/*ultrasonography ; Diuretics/pharmacology ; Dogs/*physiology ; Feasibility Studies ; Furosemide/pharmacology ; Mannitol/pharmacology ; Reference Values ; Reproducibility of Results ; Ultrasonography, Doppler/*veterinary ; Vascular Resistance/drug effects/*physiology

OBJECTIVETo discuss the mechanism of cerebral vessel spasm caused by concussion and the effect of Nimodipine on concussion.

METHODSA total of 224 patients who were treated from March 1995 to October 1999 were divided into two groups randomly, ie, Nimodipine group (113 cases) and control group (111 cases). Middle cerebral artery (MCA), basilar artery (BA) and the average peak forward velocity of cerebral blood flow were observed by color three-dimensional transcranial Doppler (3D-TCD) within 24 hours after admission and at the end of 3-6 days of treatment. Cerebral blood flow changes, characteristics and treatment effect were analyzed and determined by clinical main symptom disappearance rate.

RESULTSIn concussion, cerebral blood flow was divided into 3 phases: cerebral blood flow low infusion dilation phase, cerebral blood vessel spasm phase and cerebral blood flow recovery phase. In the Nimodipine group, clinical main symptom disappearance rate was higher than that in the control group in the cerebral spasm and recovery phases with a significant difference (P < 0.01).

CONCLUSIONSCerebral vessel spasm, hypoxia and ischemia lesion are the main pathological changes. Whether cerebral dysfunction is reversible or not is mainly determined by spasm time of cerebral blood vessel. Nimodipine has a good effect on releasing spasm and diminishing the cerebral blood flow velocity. It not only improves curative effect on concussion, but also reduces and prevents concussion sequelae. Hence, concussion patients who have cerebral spasm confirmed by 3D-TCD should be given Nimodipine routinely and early.

Adolescent ; Adult ; Aged ; Blood Flow Velocity ; Brain Concussion ; complications ; diagnostic imaging ; Cerebral Arteries ; diagnostic imaging ; drug effects ; Cerebrovascular Circulation ; drug effects ; Dose-Response Relationship, Drug ; Drug Administration Schedule ; Drug Therapy, Combination ; Female ; Follow-Up Studies ; Humans ; Infusions, Intravenous ; Injury Severity Score ; Male ; Mannitol ; administration & dosage ; Middle Aged ; Nimodipine ; administration & dosage ; Reference Values ; Treatment Outcome ; Ultrasonography, Doppler, Transcranial ; Vasospasm, Intracranial ; drug therapy ; etiology ; physiopathology