Affection of small cerebral vessels participate in serious diseases such as lacunar infractions and subcortical vascular dementia. In coloured transcranial duplex sonography for evaluation of vascular resistance Pourcelot's resistance index (RI) is used. The authors tried to find out whether it is possible to use RI in the diagnosis of affections of small cerebral vessels (small vessel disease) and find a borderline between pathological and normal findings. Transcranial coloured coded duplex sonography (TCCS) was used in 45 patients hospitalized on account of acute ischaemic cerebral attacks and who had clinical or radilogical (CT, MRI) signs of affection of arterioles. Among clinical signs they included: patients with the clinical picture of lacunar infractions, vascular extrapyramidal syndrome signs of subcortical vascular dementia and quadrispastic syndrome. Among CT or MRI signs the authors included: signs of leukoaraiosis,multiple bilateral capsular infractions, subcortical infractions, lacunar infractions in the brainstem. On an HDI ATL 3000 apparatus by means of a linear probe 5–10 MHz a duplex examination of extracranial vessels was made followed by transcranial examination on the same apparatus by a sector probe 2–3 MHz. Flow rates in both middle cerebral arteries (MCA) (n = 80) were assessed: peak systolic velocity (PSV), enddiastolic velocity and Pourcelot's resistance index. The assessed values were compared with a control sample of the same number MCAs (n = 80) in subjects without cerebrovascular disease. In the group of patients the following values were obtained: PSV = 80 cm/s, EDV = 28 cm/s, RI = 0.65; in the control group: PSV = 90 cm/s, EDV = 38 cm/s, RI = 0.58. The values in the two groups were compared using the non-paired Student t-test. For PSV p < 0.001, for EDV p < 0.0001, for RI p < 0.001. The cut off point was RI = 0.62 with 70 % sensitivity and 80 % specificity. The study provided evidence of a higher RI with lower PSV and EDV in the group of patients with signs of small vessels disease as compared with the control group. In the authors opinion RI proved as an auxiliary diagnostic tool for assessment of affections of the small cerebral vessels.

        Key words: coloured transcranial sonography, small vessels disease, resistance index