Medical Ultrasound Imaging Abbreviations - G 1 - 3 (of 3) •GA-GS • GA Gestational Age • GI Gastro-Intestinal • GS Gestational Sac 1 - 3 (of 3) •GA-GS Thus the metric system did not really catch on in the States, unless you count the increasing popularity of the nine-millimeter bullet. - Dave Barry |