measure the intracranial pressure. Approximately 1 cc of indigo carmine is injected into
one of the ventricles and allowed to diffuse for a period of several minutes. The
cerebrospinal fluid is allowed to drain slowly from the two ventricles and is carefully
collected in a graduate for measuring. To promote drainage, the patient's head is
positioned so that the exposed portions of the cannulas are dependent. The patient's
head is then positioned so that one cannula is lower than the other to permit the
cerebrospinal fluid to drain from the lower cannula while air (the contrast medium) flows
into the ventricular system through the upper cannula. This procedure is continued until
approximately 25 to 30 cc of the cerebrospinal fluid has been withdrawn and replaced
(2) This phase of the examination may vary. For example, drainage of the
cerebrospinal fluid may be accomplished by means of a syringe (Luer type) attached to
the cannula with flexible tubing. In this method, small quantities of cerebrospinal fluid
are withdrawn (5 to 10 cc at a time) and replaced with carbon dioxide (CO2). This
procedure is continued until gas instead of fluid is returned upon aspiration.
(3) When the injection of the contrast medium has been completed, the
cannulas are removed, the scalp is sutured, and a dressing is applied. Immediately
following this, the patient is brought to the x-ray room for the ventriculographic
c. Radiographic Procedure.
(1) Basic routine. Ordinarily, AP, PA, and right and left lateral projections of
the skull are first made with the patient in a horizontal position. Then a similar set is
made with the patient in an upright (sitting) position. The exposure factors are usually
the same as those used for routine skull examinations.
(2) Central ray-part relationships. For the sagittal (axial) projections (that is,
AP and PA), the vertically or horizontally projected CR is directed along the IOML
(infraorbitomeatal line) and in line with the midsagittal plane of the skull. The laterals
are made similarly to routine laterals of the skull.
(3) Additional positions and projections. Additional projections may be
taken in various positions with various CR relationships to include any one or several as
shown in Table 3-2.