Babeh Edi

Oral Cholecystogram

Indications for imagingNote: Sheering stopped UK production of oral agents in 2004 Biliary tract imaging to demonstrate the gall bladder and cystic duct. Contra-indications Proven hypersensitivity to iodinated contrast agents Sever hepatic renal disease Dehydration Cholecystectomy Anatomy  Demonstrated Radiographic Anatomy of the gall Bladder region Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London Technique The examination is a three stage process, * See the notes on Biliary Contrast agents in the Contrast media section of the site 1) Day 1 the patient takes a laxative for two days prior to the examination days, (check contraindications to laxative preparation, care with diabetics, and conditions like Crohns disease) 2) Day 2 a single control radiograph of the whole abdomen or the right side of the abdomen This film is then examined to determine, the position of the gallbladder (level with the upper margin of the hepatic flexure of the colon, to demonstrate any radio opaque calculi, evaluate the efficacy of the laxative preparation and judge the exposure for the second part of the examination. The morning of the day before the examination the patient is encouraged to have a high fat meal to empty the gall bladder. The evening before the examination the patient takes the oral contrast agent tablets as directed by the manufacturer, typically 3 grams of Calcium Ipodate (Biloptin) with plenty of water, the patient remains nil by mouth except for water until the examination 14 hours after taking the contrast medium. 3) The day of the examination Check the patient has taken the tablets as directed, followed the dietary instructions and not been sick or had diarrhoea. A typical film sequence is an erect and supine image the gall bladder region with the patient positioned in the left anterior oblique position. generally thin patients require more obliquity up to 45 degrees than large patients who may only need 10 degrees rotation to project the gall bladder free of obstructions. AFM or After Fatty Meal Film. If the gall bladder is adequately demonstrated with obvious calculi then a fatty meal is given, either a proprietary product such as "Prosperol" or a glass of full fat milk and a mars bar, 40 minutes later the gall bladder is imaged in whichever projection best demonstrated it in the first two films. If the gall bladder is not visualised and the patient has complied with all the instructions it may be due to intolerance to the contrast agent, or an ectopic gall bladder, a full 35 x 43 cm abdominal film may demonstrate an ectopic gall bladder or may show undigested contrast agent in the small bowel, If there is only feint opacification of the gall bladder some centres recommend a double dose or repeat dose of contrast agent, however this needs to be discussed with e radiologist before being undertaken and be in line with departmental protocol. Basic Patient Position Patient Position Left Anterior Oblique Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London Radiation protection "28 Day Rule" Direct lead rubber waist level protection Central Ray The vertical central ray is centred midway between the skin flank and the palpable spinous processes at he level of the lower costal margin, note that in the erect position the gall bladder may drop as much as 8cm, sometimes below the level of the iliac crest. Cranial angulation of the central ray up to 15 degrees may be useful to avoid gas shadows. Exposure Factors Kv mAS FFD (cm) Grid Focus AEC Cassette 70 60 100 Yes Broad Yes 18 x 24 cm Evaluation of the Image ID and anatomical markers must be present and correct in the appropriate area of the film. Optimal exposure should penetrate all the bone structures and contrast should be low enough to visualise fully the soft tissue structures. Examination sequence timing markers must be present.  Radiographs Note Schering Discontinued Biloptin in 2004 Related Projections The combination of erect and prone imaging positions should enable the gall bladder to be projected free from overlying gas and faecal shadows, however a lateral of the region either erect or prone may sometimes be required or in extreme cases tomography.   Complications Gastro intestinal disturbence is common Urticarial skin reactions, vasodilation and pruritus are rare. Acute pain may result if a calculus becomes lodges in the cystic duct following the fatty meal. Impaired renal function Uricosuric action Pseudoalbiuminaria Abmoramal thyroid function tests for up to 3 months Increased efficancy of protein bound drugs. Patient aftercare. General non specific.Additional modalities Ultrasound is the primary imaging modality for the gall bladder, however CT is useful in difficult cases along with MRI. Useful Reference: Ref: A guide to radiological Procedures by Chapman & Nakielny 2 nd Edition