<prompt> Rim Sign on Contrast Studies of kidney is seen in?Chronic HydronephrosisRenal Coical NecrosisRenal Papillary NecrosisRCC  <response>: RIM SIGN-Chronic Hydronephrosis REVERSE RIM SIGN-Renal Coical Necrosis RIM sign indicates the markedly thinned out atrophic renal parenchyma surrounding the dilated pelvicalyceal system in Chronic Hydronephrosis 