["Radial artery catheterization is gaining popularity for diagnostic and interventional procedures. Palpation technique is widely used for the procedure, but ultrasonography has been shown to increase catheterization success. A recently described ultrasonography technique is termed 'dynamic needle tip positioning'. We aimed to compare the traditional palpation technique and dynamic needle tip positioning technique in regard to clinically relevant end points.", 'The study was conducted as a randomized, patient-blinded, crossover study. Patients underwent bilateral radial artery catheterization using both techniques. The primary end point of the study was needle manipulation time. Additional end points were (1) the number of skin perforations, (2) the number of attempts targeting the vessel, (3) the number of catheters placed in first attempt and (4) the number of catheters used.', 'Forty patients were analyzed. There was no significant difference in median needle manipulation time [32 s (range 11-96 s) vs. 39 s (range 9-575 s), P = 0.525], although the variance was lower in the dynamic needle tip positioning group (P < 0.001). In the traditional palpation technique group, a higher number of skin perforations (57 vs. 40, P = 0.003), catheters (46 vs. 40, P = 0.025) and attempts targeting the vessel (104 vs. 43, P < 0.001) were necessary compared with the ultrasonography dynamic needle tip positioning group. First attempt success rate was significantly higher in the ultrasonography dynamic needle tip positioning group (23/40 vs. 38/40, P < 0.001).'] Is ultrasonography-guided radial artery catheterization superior compared with the traditional palpation technique : a prospective , randomized , blinded , crossover study?