plain film CT scan MRI US RCM (contrast media ) plain film CT scan MRI US

IV contrast :"in general IV RCM are circulate within the vascular system but do not cross the normal blood brain barrier Iodinated CM (iohexol) used in CT sacn & Plain film more stable less toxic , less expensive each molecules are tri-iodinated nonionizing ( contain 3 atom of iodine to 1 osmotically active particle) which give large iodine that provide good opacification

Complication Minor complication Intermediate Sever life threatened complicated Death

Risk factors : 1.A previous reaction to RCM 2.Asthma . 3.hypersensitivity to iodine 4.B-blocker 5.heart disease 6.infant & small children 7.Hepatic failure . 8.imapired renal function 9.multiple myoma (myelomatosis ) 10. poor hydration 11.scicle cell anemia 12.adminstation of metformin(glucophage ) .

IV Contrast agent in MRI(Gd Chelates ) : It used to enhance the inherent contrast between the tissue , it alter the rate of relaxation of proton within the tissues . Gadolinium(DTPA) , Shortening the T1relaxation time & hence produced increasing SI (white )on TI images

Gd Indication CNS tumor & recurrency Demylinating disease Cardiac & aortic imaging Contraindication : No absolute CI , Limited used in pregnancy particularly in 1st trimester

GIT Ba sulphate Advantage : Its provid excellent opacification , good coating of the mucosa and completely inert . Cost

Disadvantage : 1.major disadvantage is that when water is reabsorbed in the colon the Ba may solidify & impact proximal to colonic or rectal stricture 2.high morbidity associated with Ba in peritoneal cavity

Complications : If there is Perforation :Ba in the peritoneal cavity is extremely serious & with produce pain , sever hypovelemic shock Aspiration :Ba if aspirate is relatively harmless , sequelae include pnemonities , granuloma formation Intravenous : result in pulmonary embolus mortality rate 80%

US CM gas microbubbles are an effective US contrast agents , bubble smaller than 7 Micrometer must be used to pass the pulmonary filter and bubbles of this size only remain intact for a seconds Levoviste