[Arteriovenous malformation. 3. Dynamic CT of arteriovenous malformation].

Various methods have been reported for the purpose of measurement of hemodynamics of the cerebral arteriovenous malformations. In this paper, using a TCT-60A-30 scanner, dynamic computed tomography was performed on 18 cases with arteriovenous malformations. The initial scan of the dynamic CT was started simultaneously with the start of an intravenous injection of uniodinated contrast medium (8 ml/sec.), serial 4.5 sec. scan repeated 8 times. The data for each scan were segmented into three, and a series of 24 rapid-sequence scan images (CT-angiography) was generated. The time-density curve by use of Thompson's methods was analyzed with multiple ROIs which were bilaterally set up for the nidus and its surrounding areas considering each arterial supply. And the flow parameters, such as the peak concentration (PC), the mean transit time (MTT) and the PC/MTT were calculated. We thought that under the condition of normal state of blood-brain-barrier and fixed standards of multiple factors such as the cardio-pulmonary function, systemic blood volume, viscosity of the blood and many others, PC manifested vascular beds of ROIs, MTT brain circulating time, PC/MTT blood flow respectively. In the ROIs of the nidus, high values of PC (115.7 +/- 51.9 CT number) and PC/MTT (14.8 +/- 6.28 CT number/sec.), and reduction of MTT (8.47 +/- 2.28 sec.) were revealed in comparison with surrounding areas. The ROIs of the nidus showed enlargement of vascular beds and blood flow and reduction of brain circulating time. On the other hand, in the ROIs surrounding the nidus, MTT of affected areas (10.33 +/- 2.78 sec.) was slow compared with it nonaffected areas (9.33 +/- 2.09 sec.), however PC and PC/MTT were equal in both areas.(ABSTRACT TRUNCATED AT 250 WORDS)