CT: A Big Hit, No Matter How You Slice It

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Cardiac imaging and 64-slice was at the heart of CT at last week's Radiological Society of North America meeting. Clinicians and vendors alike are eyeing CT's capabilities to noninvasively step into the realm of diagnostic catheterization, making CT the screening grounds for the cath lab.

Each of the four major CT vendors showed off their 64-slice scanners at the meeting, as many units that debuted at last year's meeting took root in facilities this year. Sixty-four slice CT brings with it the speed necessary to stop a beating heart, literally.  Clinicians report excellent image quality of previously hard-to-image coronary arteries and images on display proved it.

Good news for radiologists came too at last month's American Heart Association meeting where a study was presented that said radiologists still play an important role in CT cardiac imaging, namely in assisting cardiologists with the incidental findings seen during CT angiography studies.

But 64-slice didn't take all the CT buzz at RSNA, with show-goers lining up to see the latest 16, 32 and 40 slice scanners have to offer at a more affordable price point. New workflow enhancements in 3D and virtual colonoscopy as well as image management solutions to deal with the image overload of high slice-count scanners gained a lot of attention. And large bore CT scanners specialized for radiation therapy applications proved popular, too.

(Note: companies appear in alphabetical order.)




GE Healthcare launched two new CT scanners, the LightSpeed VCT and the LightSpeed Pro32 and, and the next-generation of its workflow-enhancing software, Xtream FX.

The LightSpeed VCT (Volume CT), which provides a combination of simultaneous wide volume coverage and high resolution via a 64-channel detector, offers 4 cm coverage and a resolution of 0.35 mm. The most significant clinical application for this system will be cardiac studies. LightSpeed VCT reduces the acquisition time for a typical exam from 20 seconds on a 16-slice scanner to about 5 seconds on this device, GE said. In a single rotation, the system creates 64 submillimeter images, totaling 40 millimeter of anatomical coverage, which are combined to form a 3D view of patient anatomy. It can noninvasively capture the heart in five beats and scan the whole body in 10 seconds, according to GE.

This capability is considered a breakthrough, GE said, because once the contrast agent is injected, there is an initial variation of heart rate produced by introduction of the agent, then there is about a five second "golden window" where the heart rate is stable, followed by an increase in heart rate as the breath-hold produces hypoxia. It is important to have a stable heart rate to produce excellent image quality across an entire population of patients who will be imaged.

The first LightSpeed VCT was installed at Froedtert Hospital in June 2004.

The second product launch involves the LightSpeed Pro32 helical multislice CT, which advances the 16 series scanners. This system is described as being incrementally better compared to the 16-slice scanners, and is beneficial for cardiac studies, angiography, and perfusion studies, GE said. Although it does provide 4 cm coverage, the resolution is not up to the standard of the VCT. 

Both scanners have an increase in scan rotation speed, moving from 400 milliseconds to 350 milliseconds as a single rotation of the detectors.  Both products will be fully commercially available in the first quarter of 2005.

GE also debuted its next-generation Xtream FX workflow technology designed to allow imaging departments to keep pace with the large volume of data generated by routine sub-millimeter scanning. Xtream FX provides thin-slice image reconstruction that GE said is 3.7 to 6.9 times faster than other industry standard platforms. It is three times faster than the existing Xtream engine.



Philips Medical Systems debuted the new Brilliance CT 64-channel scanner, the big brother of the Brilliance 40-channel scanner, as well as touting a new large bore CT scanner for radiation oncology.

The Brilliance CT 64 scanner delivers thin-slice acquisition for the full width of the detector module by increasing the number of simultaneously acquired data acquisition channels to 64 per rotation, Philips said. Applications include neuro, body, pulmonary, cardiovascular, pediatric, interventional and trauma studies. Commercial shipments are scheduled to begin in June or July 2005, according to James Fulton, VP, global marketing PMS CT.

The Philips Brilliance Workspace 2.0 is adaptable across the Brilliance family. The newest software version features packages for assessing lung nodules, emphysema and cardiac CT. A new virtual colonoscopy package provides a detailed view called Filet, which portrays the interior of the colon as a landscape to make routine interpretation time less than 10 minutes, down from an hour or so. The package will be available in the early spring.

The new Brilliance CT Big Bore Oncology replaces the AcQSIM CT. Designed for radiation oncology, the scanner features 60 cm TRUE SCAN field of view and an intuitive workflow environment. It allows breast positioning, prostate treatment, respiratory gating studies, integrated absolute marking and functional CT scans. A CT localization (CT L.O.C.) application is on the console, allowing clinicians to localize the tumor and mark the patient for therapy delivery without leaving the console.



Siemens Medical Solutions at RSNA debuted two new members of its CT family - the entry-level, sub-second, dual-slice SOMATOM Spirit and a new 40-slice scanner called the SOMATOM Sensation 40. Siemens also showcased its new SOMATOM Sensation Cardiac 64. At showtime, Siemens said it has installed 100 64-slice scanners, with 150 expected to be sited by year's end.

The SOMATOM Spirit acquires two slices per rotation, but is priced in the single-scanner range, Siemens said. The SOMATOM Sensation 40 features Siemens z-Sharp technology, and enables acquisition of 40 slices per rotation with unprecedented image quality and isotropic resolution of below 0.4 millimeter voxel size in clinical routine. Applications are focused on cardiac and vascular work, according to Bernd Ohnesorge, VP, CT marketing and sales.

The company is touting the SOMATOM Spirit as a solution to replace outdated single-slice axial or spiral scanners, as an additional CT in an overworked facility, or for an affordable entry into CT. One site in China, Siemens said, is scanning 75 patients per day on the system. It is also fitting for small, outlying clinics utilizing teleradiology, ENT and urology practices, dental surgeons, orthopedic physicians and general practitioners. It can be sited in 183 square feet and can accommodate up to 50 patients in an eight-hour workday. The system features slice-width of one millimeter (mm) and a gantry rotation of one second. A 0.8 second gantry rotation is available as an option. The gantry measures 70 centimeters and the patient table load of 200 kilograms. 

Scanners have already been installed in Europe and Asia, with U.S. commercial availability slated for spring 2005. The first U.S. installation is expected in February.

The SOMATOM Sensation 40 features z-Sharp technology and the STRATON x-ray tube. The STRATON tube utilizes an electron beam that is accurately and rapidly deflected, creating two alternating and overlapping x-ray projections reaching each detector element. This doubles the scan information without a corresponding increase in dose, resulting in substantially enhanced spatial resolution and image quality, Siemens said. The system combines Speed4D Technology and a gantry rotation speed of 0.37 seconds. The system can be upgraded on-site to a 64-slice scanner.

Clinical testing is ongoing in the U.S. and Europe, with commercial availability expected in the summer.

Siemens Medical Solutions also showcased its new SOMATOM Sensation Cardiac 64. Optimized for cardiac, thoracic and vascular imaging, this 64-slice CT system enables an ECG-gated coverage of the entire chest in a 20-second breath-hold. The system features a 0.33-second rotation time and z-Sharp Technology to deliver optimal image quality with a spatial resolution of 0.4 millimeters. The Somatom Sensation Cardiac 64 is designed to provide enhanced spatial resolution and image quality without an increase in x-ray dose. The system's temporal and isotropic spatial resolution may now allow for virtually motion-free visualization of peripheral segments of the coronary arteries including plaque evaluation and post-stent patency assessment. The first unit was installed at the Mayo Clinic in August, and these scanners are now commercially available.

Among the advanced applications for CT that Siemens introduced at RSNA were syngo Colonography with PEV (Polyp Enhanced Viewing) software, the first FDA 510(k) cleared and commercially available enhanced colon viewing technology, the company said. Future CT applications from Siemens include Advanced Bone Removal for syngo InSpace4D, syngo Body Perfusion CT, and CT Respiratory Gating for radiation therapy planning. Advanced Bone Removal and Respiratory Gating are currently under 510K review. syngo Body Perfusion is a works in progress. These applications are expected to be available in mid-2005. Siemens currently offers NEV, Nodule Enhanced Viewing.

Polyp Enhanced Viewing (PEV), an optional add-on to the syngo Colonography application, is designed as a second-reader tool for automated identification of lesions in the colon. PEV can be activated as the radiologist begins the primary read, with the results ready for reviewing as the radiologist confirms the end of the primary read. The PEV tool then highlights potential lesions that were not marked by the radiologist, in addition to all potential lesions marked by the radiologist during the first read, and also indicates potential lesions marked by the radiologist that were not visualized by the PEV tool. Further workflow enhancements to syngo Colonography include automated polyp measurement and visualization of unseen areas.

Lastly, Siemens showcased its SOMATOM Sensation Open 20-slice scanner for CT-based radiation therapy planning and for other CT applications where patient accessibility and advanced CT performance are required. Among the applications Siemens sees for the system are diagnostic support for radiation therapy planning, CT-based trauma examinations, interventional procedures and imaging of bariatric patients. The SOMATOM Sensation Open features an 82-centimeter gantry bore and 82-centimeter field of view and 0.5 second gantry rotation speed. A works-in-progress table will have a 600-pound capacity, namely for bariatric work, and be available mid next year. Ten units have been installed since installs began in the summer.



Toshiba America Medical Systems at RSNA showcased its new Aquilion 64 CFX CT system for coronary artery exams, announced a new cardiac CT clinical study and entered the oncology and radiation therapy planning CT market segment with the debut of the Aquilion LB large bore scanner.

The Aquilion CFX, which has been installed at 10 facilities across the globe, including three in the U.S., features Toshiba's 64-row Quantum detector for simultaneous 64-slice scanning with a spatial resolution of 0.35 millimeter, volume imaging capabilities and proprietary software applications designed to automate complex diagnostic cardiac studies, said Doug Ryan, director, CT Business Unit. The three U.S. sites are Beth Israel Deaconess Medical Imaging Center (BIDMC) in Boston, Steinberg Diagnostic Medical Imaging Center (SDMI) in Las Vegas, Methodist Hospital in Arcadia, Calif. The Aquilion 64 will achieve full production for worldwide shipment in Q1 2005.

The system's software applications suite, known as SUREWorkflow, is designed to ensure image quality, repeatability and productivity by automating complex CT studies. The Aquilion CFX has a new cardiac visualization software package, SUREPlaque, that just gained FDA marketing clearance. The SUREPlaque option identifies and quantifies soft plaque for cardiac and peripheral vessel analysis using a color-coding system based on tissue density.

The Aquilion LB features a 90 cm bore with an 85 cm display field-of-view and a 70 cm acquired field-of-view, Ryan said. A new table design, which enables a tilt up to 25 degrees and patients arms extended over their head, makes the system more versatile and capable of imaging almost every patient type and profile. The system is equipped with the Quantum multi-row CT detector like the rest the Aquilion family of products, which enables image slice thickness of 0.5 mm. The works-in-progress system is expected to gain FDA 510(k) marketing clearance in February, with beta tests beginning in March. A full commercial release is slated for the American Society for Therapeutic Radiology and Oncology (ASTRO) meeting in October.

Toshiba also is embarking on a multi-center clinical study with its foremost luminary partners around the globe on computed tomography (CT) coronary angiography imaging. The CorE 64 (coronary evaluation on 64) study is focused on validating multislice CT use as the primary diagnostic tool for detecting cardiovascular diseases and defects, as compared to cardiac catheterization. The study began in November and includes Johns Hopkins University School of Medicine, Baltimore, Md.; Beth Israel Deaconess Medical Center, Boston, Mass.; Leiden University Medical Center, The Netherlands; Humbold University, Campus Charité Mitte, Germany; INCOR Heart Institute of the School of Medicine Hospital, Sao Paulo University, Brazil; Iwate Medical University, Japan.



A HELPING HAND FOR CT


Cardinal Health featured a new CT dose phantom at RSNA that provides one complete set of quality assurance dose phantoms for children and adults. It consists of three parts: an adult body phantom, an adult head phantom that doubles as a pediatric body phantom, and the new pediatric head phantom. Each phantom can be purchased separately or combined in a kit according to a particular practice's needs. In addition, an optional sturdy carrying case has been designed to hold all three phantoms and a CT Ion chamber.

DynaWell, Inc. showcased its DynaWell L-Spine compression harness at RSNA. L-Spine is designed to be used in conjunction with CT and MRI systems to provide a more accurate diagnosis of spinal conditions by simulating the weight and load of upright posture. Currently, because virtually all CT and MRI exams occur when a patient is lying down and free from the effects of gravity, many spinal diseases, injuries and conditions may go undetected or be improperly diagnosed. The L-Spine simulates the axial compression on a patient's spine when standing. It can be used on lumbar spine pathology, such as spinal stenosis, sciatica, disc herniation and synovial cysts, as well as in hip, knee and ankle pathology. It has been approved by the FDA and is available for sale or lease in the U.S. and worldwide.

Medrad Inc. debuted the Stellant D CT Injection system that looks to improve diagnostic CT images of the coronary arteries with fewer artifacts. The Stellant with the  DualFlow option enables both contrast and saline injection at the same time through variable ratios of synchronized plunger motion. With the proper ratio, the left and right heart ventricles can be illuminated uniformly, Medrad said. The device includes a pressure monitor graph, improved syringe design, syringe auto load and the ability to upgrade from single to dual injection.

TeraRecon launched a new, scalable cone beam CT reconstruction cluster based on the Xtrillion processor technology. The system delivers CT reconstruction of a 2048 cube in less than 30 minutes. To enhance its line of high-resolution, high-speed 3D cone beam CT scanners, TeraRecon also announced two additional configurations with sub 10-micron resolution.



PHILIPS DEBUTS 'AMBIENT EXPERIENCE' FOR MORE PATIENT-FRIENDLY CT IMAGING


Advocate Lutheran General Children's Hospital in greater Chicago is the first healthcare facility to install what Philips Medical Systems calls the child-friendly "ambient experience," a snapshot of which was on display for RSNA-goers to tour.

The ambient experience includes Philips lighting and consumer electronics that creates a patient-friendly scanning environment. At RSNA, attendees saw a child-friendly imaging theatre centered around age-appropriate themes, such as space travel, geared toward reducing anxiety and providing entertainment to reduce the time needed to take medical images as well as reduce the number of patient sedations.

The project at Advocate Lutheran sought to make the imaging experience less intimidating for small patients in creating an imaging center for children. The newly designed suite at the hospital's Yacktman Children's Pavilion features a Philips Brilliance CT scanner in a room with curved walls, creating a softer emotional environment. Patients can choose a mood theme - or "ambient environment" - for the room by waving a radio frequency card over a reader, which triggers special lighting and animated images projected onto the walls and ceiling using Philips technology.

"Pediatric patients range in age from infants to teenagers - we wanted a place that was comfortable for all age groups," said John Anastos, chairman of the department of radiology at Advocate Lutheran. "We also expect that the lighting and visual effects will lower stress for both the patients and their families, making the experience better for everyone."

Philips said the ambient experience is the work of some 400 designers, including social psychologists and anthropologists who collaborated to personalize the imaging experience and make it child-friendly. This included the creation of a "kitten scanner," a faux mini-CT scanner that entertains patients in the waiting room prior to their scan with the help of stuffed animals - such as a chicken or an alligator - containing RF ID tags that when placed in the scanner prompt a movie to be displayed on the wall.