(b) The patient is placed on the operating table in the supine position
and draped for surgery. The specialist placed the portable Bucky grid or the cassette
tunnel underneath the patient and centers the film in line with the siphoid process of the
sternum and slightly to the right of the midline.
(c) A preliminary film (10 x 12-inch or 14 x 17-inch) is exposed and
immediately process. This film is used to check the centering of the film and the
correctness of the technique factors.
(d)
Anesthesia is induced and the operating field is prepared for
surgery.
(e) After surgical exposure, a plastic catheter is inserted into one of the
tributaries of the portal vein, advanced into the portal, and then tied in place.
(4)
Injection of contrast medium and radiography. See figure 3-13.
(a) An automatic injector syringe filled with 60 to 120 cc of a contrast
solution is attached to the exposed end of the catheter. Meanwhile, the specialist will
move the x-ray unit in place and center the tube over the area indicated by the surgeon.
Before positioning the tube, the surgical site must be covered with a sterile towel or the
tube assembly wrapped with a suitable sterile material.
(b) With all participants alerted, the surgeon gives the "Ready," signal
to the specialist and then starts injection of the contrast solution at a rate of 10 to 15 cc
per second. Immediately upon completion of the injection, the first exposure is made.
In some instances, the surgeon may instruct the anesthetist to induce apnea for the
duration of the exposure in order to help overcome the possible loss of image detail
caused by respiratory movement in the patient. This is especially advantageous in
cases where a low-powered mobile x-ray unit is all that is available for use in the
operating room. When apnea is induced, two factors are of prime importance.
1 The surgeon must determine the optimum time for the
commencement of the injection concurrent with the inducement of apnea
2 The specialist must be prepared to make the exposure at the
required instant.
(c)
Subsequent exposures are made at predetermined intervals.
(5) Procedural variations. When the contrast medium is introduced by the
transhepatic or the occlusal method, operating room facilities are not necessarily
required. This is advantageous since it permits the use of automatic rapid-sequence
serializing biplane exposure apparatus.
MD0959
3-35