CHOLECYSTOGRAPHY AND CHOLANGIOGRAPHY

GALLBLADDER

General Radiographic studies of the Gallbladder are rarely done. These studies have been replaced with other modalities such as ultrasound.

 (1) Radiographic visualization of the gallbladder is done by cholecystography. Radiographic investigation of the biliary tract is by cholangiography. For these procedures, it is necessary to convey a contrast medium to the gallbladder along with the bile.

 (2) Bile is manufactured by the polyhedral cells of the liver which extract the necessary constituents from the circulating blood. The gallbladder's ability to concentrate the bile makes it possible for a sufficient amount of the cholecystopaque to collect within the gallbladder to permit radiographic visualization. After oral administration, the contrast medium, if in pill form, disintegrates in the stomach.

 (a) Most of the contrast medium is absorbed in the small bowel and connveyed to the liver via the portal vein.

 (b) As the contrast medium moves throughout the liver, it becomes associated with the liver cells and is secreted with the bile.

 (c) As the bile containing the contrast medium passes along the ducts, some of it is discharged into the duodenum and some of it backs up into the gallbladder where concentration occurs.

 (d) The elimination of the contrast medium from the body is dependent upon various factors such as the type of contrast medium and the nature and degree of dysfunction related to the digestive system. Normally, some of the contrast medium is

not absorbed, but is eliminated via the colon. The kidneys eliminate the part that is not

removed from the blood as it passes through the liver.

(e) As the gallbladder discharges the bile containing the contrast medium into the small bowel after the ingestion of fatty meal, the medium is reabsorbed

and conveyed to the liver and secreted again. This cycle continues until the contrast medium is completely eliminated from the body via the kidneys and colon.

 b. Preparation of Patient and Scheduling.

Patient preparation and scheduling are in accordance with the established clinical routine. In general, the preparation of the patient may be as follows.

 (1) On the day before the examination (before ingestion of the contrast medium), a PA projection of the abdomen (11x14) may be done. This is a survey or scout film.

 (2) The patient is not allowed to eat fats after the noon meal the day before the examination.

 (3) About 12 hours prior to the examination, the patient ingests the contrast medium according to the manufacturer's instructions. Telepaque is usually used with the average dose being 6 tablets.

 (4) After taking the pills, the patient should not be allowed to eat or drink anything until the time of the examination.

 (5) To make certain that none of the contrast medium has been lost, the patient should be instructed to report any vomiting or bowel movements.

 (6) If the initial films show no stones, the patient is given a fatty meal to promote good gallbladder contraction. An additional film is usually done 30 minutes to one hour after the fatty meal. Sometimes commercially prepared compounds or

mixtures may be used in place of the fatty meal.

NOTE: Before giving a fatty meal, consult the radiologist. A fatty meal should not be given to patients if stones are seen in the initial films). This precaution is necessary because the "emptying" of the gallbladder caused by the fatty meal may release one or more stones into the biliary ducts causing obstruction.

 (7) The procedure may vary since every radiologist has his preferred method. For example, some radiologists may request that the patient be given two teaspoonfuls of paregoric one-half hour after the ingestion of cholecystopaque or that an enema be administered one hour prior to radiography.

(8) For an examination of the biliary ducts (by the intravenous injection of Cholografin), the referring ward schedules and provides the preparation of the patient. Usually, the patient does not eat anything after 1800 hours on the day prior to the

examination. On the morning of the examination, the patient is given a sensitivity test.

If the test is negative and there are no contraindications, 20 to 40 cc of the cholecystopaque is injected intravenously by the radiologist. This examination is done in the operating room using sterile techniques.

CHOLECYSTOGRAPHY

 Cholecystography is a radiographic procedure for the demonstration of the gallbladder after making the bile radiopaque by means of a contrast medium, which may be administered either orally or intravenously.

 a. Oral Method.

 (1) The patient is prepared in accordance with the prescribed pre- examination procedure.

 (2) The contrast medium is administered according to prescribed procedures.

 (3) Upon reporting to the x-ray department, the patient is dressed in a suitable gown. He should be questioned as to how he carried out each step of the pre-examination procedure and whether he experienced any vomiting or diarrhea. If any vomiting or diarrhea occurred, the x-ray specialist should report it to the radiologist.

 (4) The number and type of projections made depends upon prescribed procedures and the suspected pathology. Usually, a survey film is made to determine the

• position of the gallbladder,
• the correctness of the exposure factors, 
• the presence and extent of gas or unabsorbed contrast medium in the bowels, and 
• evidence of outstanding pathology. 

Details of the scout film are described below and illustrated in figures below .  

 (a) Anatomical - General localization of the gallbladder.

 (b) Film - 14x17-inch film, and lengthwise. (Some radiologists prefer a 10x12-inch film.)

 (c) Position - The patient is prone with arms alongside the body. He is positioned as for a PA abdomen exposure with the crest of the ilium 3 inches below the  center of the film.

 (d) Central Ray - The CR is aligned to the center of the film.

 (e) Precaution - Suspended expiration straight.

(5) Other films may include the following.

 (a) PA prone projection using an 8 x 10-inch film and a tightly restricted cone field.

 (b) LAO using a tightly restricted cone field (6 inches) and an 8 to 10-inch film. This radiograph may be done with the patient recumbent or erect. This position tends to displace the transverse processes of the vertebrae away  from the gallbladder. The body is rotated 20º to 30º. The degree of body rotation  necessary for optimum demonstration of the gallbladder varies according to body habitus and position; for example, thin subjects generally require greater rotation than

stout subjects. Varying degrees of rotation may be necessary to differentiate gallstones from kidney stones or calcified bodies in the mesenteric structure.

 (c) Right lateral projection with the patient in the recumbent position, utilizing an 8 by 10-inch film and a restricted cone field.

 (d) PA projection with the patient on his right side (Kirklin) using an 8 by 10-inch film, restricted cone field, and vertical Bucky diaphragm or grid-cassette.

 (e) RPO (right posterior oblique) using an 8-inch x 10-inch film and a restricted cone field. This radiograph may also be done with the patient in either the recumbent or erect position.

 (6) Radiography of the gallbladder with the patient in the erect position may be done by the using essentially the same relationships with reference to part, film plane, and alignment of the CR. The erect position will cause the bile laden with

cholecystopaque to stratify into fluid levels according to the degree of concentration and relative specific gravity. The gallstones, which are lighter than certain layers of the bile, will float and, upon floating together, form a "density layer" which renders them radiographically demonstrable. Small, but heavier-than-bile, stones will tend to gravitate to, and collect in, the fundus portion of the gallbladder. In addition, the gallbladder tends to shift downward, backward, and towards the midline. Therefore, when the

patient is first x-rayed in the recumbent position and then in the erect position, some modification of the CR alignment is necessary for the latter position (approximately 1 1/2 to 2 1/2 inches lower).

Figure 2 Left anterior oblique position for radiography of the gallbladder.

NOTE: Body habitus variation: Hypersthenic(broad), gallbladder is more horizontal, 2in. higher and more lateral; Asthenic(thin), gallbladder is more vertical,   2in. lower, near the midline of body.

(7) Special methods for radiography of the gallbladder may include the use of spot-film or tomography.

 (a) Spot-filming - Following exposure and processing of the survey film, the patient is positioned under the fluoroscope, and the radiopaque gallbladder is  localized. Various spot-film exposures may be obtained with the patient in either the  recumbent or the erect position.

 (b) Tomography - Though still used, has mostly been replaced with computerized tomography and ultrasound. After accomplishing the routine survey film,  the radiologist specifies the number of layers or "cuts" to the spot-filmed and also the  level at which each is to be made. By the use of tomographic technique, it is possible to  avoid troublesome gas pockets and loculi or, at least, to lessen their adverse effects.
 Also, under certain conditions, gallstones casting doubtful densities when produced by conventional radiography can be more readily distinguished.

 (c) Ultrasound - A preferred method of visualizing the gallbladder is the ultrasound. This reduces the patient’s exposure to ionizing radiation.

 (8) The cholecystographic series is usually terminated with the final film begin taken 1/2 to 1 hour after ingestion of a "fatty meal" that is given to the patient immediately after satisfactory demonstration of the gallbladder.

 b. Intravenous Method.

(1) The preparation of the patient and the radiographic procedure are essentially the same as for the oral method. The patient is given nothing by mouth the night before. The difference lies in the contrast medium used, the time at which it is

introduced, and the method of introduction.

(2) A cholecystopaque, such as cholografin sodium, is injected into the vein of the arm.

(3) Radiographic examination is made in accordance with established routine--usually about 4 hours after injection. Additional films may be taken at subsequent intervals.

 (4) A fatty meal is given to the patient if this has been ordered by the radiologist.

CHOLANGIOGRAPHY

 Cholangiography is a procedure for the demonstration of the biliary tract after the introduction of a contrast medium. The contrast medium may be introduced by either of two methods:

• direct. 
• intravenous.

a. Direct Method. The direct method embraces two types of procedures:

1. operative (immediate) and
2. postoperative (delayed).

 (1) Immediate or operative cholangiography.

 (a) This procedure is carried out in the operating room. The surgeon aspirates the bile in the ducts and injects a contrast medium such as Hypaque or Hippuran into the duct.

 (b) A mobile x-ray unit, a portable high-speed grid cassette, and an adequate supply of loaded cassettes, are used. The cassette tray with handle is first loaded with a cassette; then it is positioned under the patient before the surgery is

started.

 (c) The cassette tray handle is graduated with a centimeter scale. A scout film is made to check positioning and the handle is marked, this enables the technician to reposition the cassette tray during surgery. All movement of the cassette tray is done at the head end of the table. Since the operative site is sterile-draped when the tube is moved into position, the x-ray specialist must ask the surgeon to point out the exact site for directing the CR.

 (d) It is necessary to use as short an exposure time as possible, especially when other than spinal anesthesia is used. If spinal anesthesia is given, the

patient should be instructed to suspend respiration during the exposure of the film. If the patient cannot respond, ask the anesthesiologist to suspend the patient's respiration during the exposure.

 (e) Since the exposure must be made at a critical time during injection of the contrast medium, the specialist should ask the surgeon to give him a signal so that he can expose the film at the proper time.

 (f) Before exposing the film, the specialist should direct his attention to the surgical site to make certain that none of the surgical instruments overlie or obscure the area to be x-rayed. This is extremely important. Failure to observe this precaution may necessitate re-exposure and delay the surgical procedure.

 (g) Exposed films should be processed immediately for reading. Additional films are made at the request of the surgeon.

 (h) The entire procedure must be carried out under aseptic conditions. Ensure that you pay attention to all sterile fields and patient drapes, taking care not to contaminate those areas.

 (i) A representative cholangiogram made during surgery is shown in figure 3A. A sketch to aid in positioning the patient is shown as figure 3B

(2) Delayed cholangiography. This examination usually follows the removal of the gallbladder and is normally performed in the x-ray department. Following surgery, a T-tube is left in place within the biliary tract for continuous drainage. Utilizing

the same type of contrast medium as for immediate cholangiography and eliminating the need of anesthesia, the material is injected through the T-tube into the biliary tract by the radiologist. The radiologist will also decide the type and the number of radiographs to be made.

 b. Intravenous Method.

 (1) Usually, the patient does not eat or drink anything after 6 p.m. on the day prior to the examination.

 (2) On the morning of the examination, the patient is given a sensitivity test. If there are no contraindications, the radiologist slowly injects intravenously 40 cc of cholangiopaque (Cholografin).

 (3) Ten minutes after the injection, the first film is made. Meanwhile, observe the patient for any reaction.

 (4) RPO radiographs are casually made to prevent superimposition of the common bile duct over the spine. Body rotation is 15 to 20 degrees.

 (5) The initial film is processed immediately and is read by the radiologist. This film also provides the specialist a means of checking for the proper positioning of the patient and the corrections of the exposure factors.

 (6) Subsequent films are exposed at 10-minute intervals for the first hour and at 20-minute intervals for the second hour. In each instance, the film is processed immediately and read by the radiologist.

 (7) Ordinarily, this completes the examination. However, under certain conditions, tomographic variations of positioning may be used.