Planigraphic Studies of the Ventricular System

Many articles have been published concerning the interpretations of conventional pneumographic roentgenograms outlining the cerebral ventricles in both normal and abnormal situations. This study concerns the use of planigraphy in studying the ventricular system and subarachnoid spaces, and the present communication is the second dealing with the visualization of the fourth ventricle and adjacent structures. A preliminary report on this subject has been published." Body-section roentgenography permits the visualization of definite levels through a complex structure. The principles involved have been discussed adequately by Moore,4 Kieffer,' Andrews,' Grossmann,2 and Wilson.7 With respect to the ventricular system, certain limitations exist, particularly in regard to radiographic positioning of the patient. Although the tube-film distance can be altered, the relation of the tube to the table top is relatively fixed with the Kieffer Laminagraph and all films must be taken with the patient in the supine, the prone, or the lateral position. It is not possible to obtain films in the erect position, the planigraphic mechanism being constructed on a horizontal table. To obtain adequate examination the structures to be visualized must be parallel to the table top and film. If the skull is turnedto the lateral projection, the midline structures, the fourth ventricle, the aqueduct of Sylvius, and the third ventricle can be visualized without interference of superimposed structures such as the mastoid portion of the temporal bone, the lateral ventricle, and the cerebrosubarachnoid sulci. This is also true in the postero-anterior view, where the fourth ventricle is usually obscured in conventional roentgenograms by the shadows of the frontal sinuses, of the bones of the base of the skull, and of the sphenoid cells.