Results of the PE tubes phantom experiments. Results of the PE tubes phantom experiments. A, A significant linear correlation was found between the gaussian SDs and the inner diameters of the PE tubes (r =. 998, P < .001). B, PVSF calibration curve obtained from the PE tubes phantom (fig 2). A significant exponential correlation was found between PVSF and gaussian SDs for the PE tubes (r =. 996, P < .001). Aleksa Cenic et al. AJNR Am J Neuroradiol 1999;20:63-73 ©1999 by American Society of Neuroradiology