CPT® Code 70015

Cisternography, as defined by CPT® Code 70015, is a specialized radiographic examination that focuses on the basal cisterns of the brain. This procedure involves the use of a positive contrast medium, specifically iodinated contrast, which is injected into the subarachnoid space through a lumbar puncture. The purpose of using a positive contrast medium is to enhance the visibility of the structures within the brain during imaging, as it has a higher absorption of X-rays, appearing as white-gray on radiographic images. Cisternography is primarily utilized to assess conditions such as normal pressure hydrocephalus (NPH) and cerebral atrophy, where the flow and absorption of cerebrospinal fluid (CSF) may be compromised. Following the injection of the contrast medium, a series of radiographic images are captured over a period that can extend from hours to days, allowing for the observation of the contrast agent's movement through the brain's cisterns. In a typical scenario, the contrast medium ascends to the basal cisterns within 1 to 3 hours and subsequently collects in the sagittal area within 12 to 24 hours. In healthy individuals, the cisterns appear clear after 24 hours, and the ventricles are not visualized during the imaging series. Conversely, in patients with NPH, the reabsorption of CSF is hindered, leading to a reversal of flow, early visualization of the ventricles, and minimal movement of the contrast into the sagittal area, with ventricular reflux also noted in cases of isolated cerebral atrophy.