Introduction: The position of the carotid artery (CCA) allows us to examine the intima and media layers (IM-complex) on longitudinal images with ultrasound. Albeit the IM echogenicity, which is used in atherosclerosis studies, can be quantified (IM-GSM: intima-media gray-scale median), contradictory results were published. Our aim was to discuss its technical background and examine other, less investigated properties of the ultrasound image of the IM-complex. Patients and methods: Ultrasound images of the common carotid artery of 52 adult, asymptomatic subjects were analyzed (21 male, 31 female, mean age: 53.6±15.1 years), who underwent ultrasound examination of the carotid and femoral arteries (Samsung RS85, LM4-15B linear transducer). Results: In our recordings performed with 4–15 MHz transducers, the standard deviation of the luminance curve of the IM pixels was more informative than the median value, which is associated negatively with the relative thickness of the two layers, the total plaque volume of the carotid and femoral arteries, obesity parameters and diastolic blood pressure. Morphological abnormalities may occur over the entire length of CCA, but are most commonly located in distal CCA, prior to bifurcation, typically characterized by irregularities, thinning, and disappearance of the intimal layer, with changes in the homogeneity and thickness of the media layer. In approximately 5–17% of the cases, “double-layered intima” phenotype can be observed. Discussion: The gray-scale of the IM complex can be interpreted in different ways when different technical capacities are given. The relative thickness of the IM complex is related to obesity and partly explains the standard deviation value of the IM gray-scale curve. Decreased standard deviation negatively correlated with the number and volume of carotid and femoral plaques. Different IM characteristics may represent distinct responses of the IM complex to endothelial injury.