Computed tomography is a well-established diagnostic technique that provides precise anatomic views throughout the body. Acknowledged for several years as the gold standard for radiation therapy planning, today’s multi-slice, high-speed scanners and 3D volume renderings have vaulted CT into the role of therapeutic workhorse in a variety of practice settings. The addition of CT fluoroscopy has proven invaluable for a wide array of therapeutic activities.

While other imaging modalities such as ultrasound may be employed for some image-guided procedures, CT offers clarity in situations where ultrasound is less functional such as imaging structures in the head and spine.

CT: Head and spine
Randall T. Higashida, M.D., clinical professor of radiology and neurosurgery and chief of interventional neuroradiology at the University of California at San Francisco Medical Center (Calif.) describes their use of CT in the management of stroke patients.

Higashida explains that when a patient presents in the emergency room with an acute ischemic stroke, a baseline CT scan determines whether the stroke is due to a clot that occludes a cerebral blood vessel, or was precipitated by an intracranial hemorrhage from a ruptured aneurysm. The next steps in treatment are directed by the results obtained from critical diagnostic imaging techniques. If a blood clot obstructs a vessel, thrombolytic therapy would be initiated, while a ruptured aneurysm might require endovascular coiling or surgery. Following initial evaluation of the patient, the CT scan provides data that inform clinicians of the precise location and extent of any brain damage that may have occurred.

“CT can determine how much blood has leaked into the brain and if the patient needs emergency surgical evacuation of the blood clot in the brain, or possibly insertion of a ventriculostomy to drain the blood,” explains Higashida. With a slight amount of brain damage, the patient may benefit from rapid therapy while extensive brain injury may signal a need to further evaluate the situation before proceeding with additional treatment.

Using their GE Medical Systems (Waukesha, Wis.) LightSpeed helical scanners, Higashida and his colleagues use sequential CT image acquisition to guide a needle biopsy for deep brain tumors where an open surgical procedure is contraindicated.

Please refer to the March 2003 issue for the complete story. For information on article reprints, contact Martin St. Denis