(b) For venography in the horizontal position, the patient is assisted
onto the x-ray table and adjusted in the supine position. The lower extremity to be
studied is aligned to the midline of the x-ray table if a Potter-Bucky diaphragm is to be
used. For nongrid technique, the region of interest is adjusted over a suitable film-
changing tunnel.
(c) For venography in the erect or the semi-erect position, the patient
stands facing the x-ray tube on a footrest that has been fastened to the x-ray table. The
x-ray table is tilted 65 to 80 degrees from the horizontal position. The footrest should be
adjusted to a high enough elevation to permit the examiner to have reasonably easy
access to the working site. An immobilization band should be placed over the patient's
chest, just beneath the armpits, to provide support. The part to be examined is aligned
to the image intensifier for digital capture. A 14 x 14-inch cassette is placed in the
fluoroscopic machine.
(d) An infusion set for saline solution should be placed in a location
that is safe and reasonably convenient to the part under examination.
(e)
The site of injection is rendered aseptic and local anesthesia is
administered.
(3)
(a) Injection may be made by the percutaneous method or by "cutting
down" and surgically exposing a vein (which is rarely done anymore). The site of
injection may be in either the retromalleolar region or the dorsum of the foot.
(b) A butterfly needle is primarily used, usually connected to a length of
plastic tubing with an adapter attached. It is inserted in the vein and secured in position
by adhesive tape.
(c) When indicated, venoclysis with normal saline solution is initiated.
In some instances, venoclysis is done in both extremities.
(d) A rubber-like tourniquet is applied around the mid-calf or above the
knee and tightened to impede the circulation in the superficial venous system.
(e) From 20 to 40 cc of a contrast solution is injected at rate varying
from 1 to 5 cc per second.
(f) The examiner signals the specialist when the first exposure is to be
made, anywhere from less than 5 seconds to more than 120 seconds following the
injection. Venograms of the leg are shown in figure 3-9.
MD0959
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