title: Use of cerebrospinal fluid gating to improve T2-weighted images. Part II. Temporal lobes, basal ganglia, and brain stem.
abstract: Ungated and gated magnetic resonance images of the temporal lobes, basal ganglia, and brain stem acquired with the use of long repetition times (TRs) and long echo-delay times (TEs), were compared quantitatively. Twenty-five pairs of images obtained on a 1.5-T system were evaluated. Ungated images (TR = 2,000 msec, TE = 80 msec) were acquired in the same manner as gated images except for TR, which, for gated studies, was determined by a patient's heart rate and generally fell into the 1,500-1,800-msec range. Three image parameters were assessed: signal-to-noise ratio (S/N), object contrast, and resolving power. In both normal and abnormal brain tissue, gated images were superior to ungated images in object contrast and resolving power and equivalent in S/N. More so than in comparable studies of the spinal cord, ungated studies were susceptible to both false-positive and false-negative interpretations. As in spinal cord studies, the major benefit of gating was the elimination of phase shift images arising from basal cisterns and the third ventricle.
mesh_terms: D001479:Basal Ganglia / Q000033:anatomy & histology* / Q000473:pathology; D001927:Brain Diseases / Q000175:diagnosis; D001933:Brain Stem / Q000033:anatomy & histology* / Q000473:pathology; D002555:Cerebrospinal Fluid / Q000502:physiology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000473:pathology