TY - JOUR T1 - Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance. JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1041 LP - 1048 VL - 11 IS - 5 AU - T C Larson, 3rd AU - W M Kelly AU - R L Ehman AU - F W Wehrli Y1 - 1990/09/01 UR - http://www.ajnr.org/content/11/5/1041.abstract N2 - Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift. ER -