New 64-Slice Computed Tomography (CT) Scanner Installed at Stanford Hospital

Posted 6:12 PM, September 5, 2008, by jaruiz

(Front row: Carol Estades, AA; Colleen Kawakami, RN; James Soriano, RT; Amy Wu, RT) (Back row: Brooke Jeffrey, MD; Dominik Fleischmann, MD; Erica Durand, RT; Monglan Duong, RT; Michele Thomas, RT, CT Supervisor; Dottie Scharff, RN; Claudia Cooper, RT, Clinical Director; Audrey Strain, RT)

By Julie Ruiz, PhD
(Images courtesy of Mark Riesenberger)

With the recent installation of a 64-slice CT scanner, the Hospital is performing state-of-the-art CT coronary studies for the first time in its history on inpatients and patients admitted to the emergency room with chest pain. Because of its improved detector technology and rotation speed, this new CT scanner produces a greater number of higher resolution images with shorter acquisition times and with a reduction in radiation exposure in smaller patients through individualized protocols.

Prior to the installation of the 64-slice scanner in the Hospital, coronary CT studies were performed at Blake Wilbur Clinic on an outpatient 64-channel system, but the Hospital is now performing state-of-the-art CT coronary angios on its inpatients and patients from the emergency room. With most "elective" outpatient CT scans still being completed at Blake Wilbur and more recently on the 64-channel CT scanner and dual-source CT scanner at Stanford Medicine Imaging Center (Palo Alto), the Hospital has greatly improved the availability of scanner slots for its inpatients and emergency room patients. Due to the striking improvements in image quality, number, and acquisition times provided by the new scanner, the Hospital can also better triage and manage emergency room patients with suspected acute coronary syndromes.

Cardiac imaging is just one area of patient care that the 64-slice CT scanner has dramatically improved. According to technologists Monglan Duong, RT, and James Soriana, RT, faster scan times mean a decrease in breath hold times for patients and an increase in the number and quality of images. For example, a typical chest scan on a 16-slice CT scanner takes 10 to 12 seconds compared to the new 64-slice scanner, which can finish a chest scan in 2 to 4 seconds. For gated-CT angio-chest-abdomen-pelvis studies on our new CT machine, patients can be scanned in 20 seconds, cutting breath hold times in half. While a 16-slice CT scanner generates around 300 to 400 images at 1.25 mm thickness for a routine chest-abdomen-pelvis scan, the 64-slice CT scanner can create 1,500 to 1,700 images at 0.625 mm thickness in less time. The faster scan speed also allows less contrast medium to be used in some cardiovascular applications.

All these improvements translate into an exciting environment for CT technologists and their supervisor, Michele Thomas, RT. Monglan Duong, RT, and James Soriana, RT, commented that the new 64-slice CT scanner has greatly increased the patient volume compared to the 8-slice and 16-slice CT scanners they currently have, and they succinctly described their reaction to the new technology: "We love it!" Since July, the Hospital has scanned more than 950 patients on the new scanner.

Paradoxically, the shorter scan times have made the planning of CT studies more challenging, requiring a greater attention to detail in order to customize a specific CT examination to an individual patient's body size, heart rate, and clinical question. Specific protocols and careful study planning are needed to take advantage of the powerful technology, which acquires data in just a few seconds when launched. The post processing of images from the 64-slice scanner is also more demanding. To extract the most useful data, the CT technologists and 3D lab must do complex reformations of the data sets. All of our technologists are highly experienced and motivated to perform this sophisticated planning and post processing, so that they can generate the best clinical images for our patients.

For prior Scan Times articles on the 3D lab and the Hospital CT team, please access http://radiology.stanford.edu/blog/archives/2007/04/3d_laboratory_c_1.html and http://radiology.stanford.edu/blog/archives/2008/03/stanford_hospit.html.