the insertion of a catheter into the saphenous vein in the region of the fossa ovalis after
the vein has been surgically exposed. In practically every case, the patient is adjusted
in the erect or the semi-erect position on the tilted x-ray table and facing the tube. The
reason this position is used is to allow the injected contrast medium to gravitate into the
dependent veins in retrograde fashion to the level of competent venous valves.
Exposures of the pelvic and upper thigh regions are made immediately after the
completion of the injection and, thereafter, as indicated by the examiner.
(5) Radiographic technique factors. The kVp is usually increased 10
percent over other exposures of the same part and the mA adjusted to hold density
constant.
3-21. ANGIOCARDIOGRAPHY
a. Patient Preparation and Administration of Sensitivity Test. This is
discussed earlier in this section (para 3-5).
b. Preliminary Procedure.
(1)
An angiocardiographic layout and the necessary solutions are prepared.
(2) Pre-examination or control films are made and developed to establish
the proper technique factors and to permit the examiner to select the most favorable
position. These films are made as soon as the patient arrives at the x-ray clinic.
(3) The patient is positioned over a specially constructed device equipped
with digital imaging capture systems (figure 3-7). Older systems have a roll-film (for
example, Fairchild) magazine which is mounted on an adjustable and mobile stand.
(4) The site of injection is rendered aseptic and then local anesthesia is
administered.
(5) A tourniquet is applied around the upper region of the patient's arm.
Then, a suitable injection needle (for example, Robb-Steinberg, 12 to 15 gauge) is
inserted into the antecubital vein, either percutaneously or after surgical exposure of the
vein. Following this, the tourniquet is removed. In some instances, however, a special
type of catheter is used for introducing the contrast medium. The catheter may be
inserted into the external jugular vein and advanced through the femoral and iliac veins
into the vena cava.
MD0959
3-25
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