FDA clearances foreshadow major releases at RSNA exhibits

January 8, 2003

November reviews come just in time for someIn a classic case of brinksmanship, radiology vendors cleared 28 devices with the FDA in November. Many were major products featured on the RSNA exhibit floor. Among them were a flat-panel

November reviews come just in time for some

In a classic case of brinksmanship, radiology vendors cleared 28 devices with the FDA in November. Many were major products featured on the RSNA exhibit floor. Among them were a flat-panel interventional detector and a PACS from GE, a six-slice CT scanner from Siemens, and an LSO-based PET/CT from CTI PET Systems.

November is typically a busy month for the industry. (The FDA cleared 28 and 24 devices in November 2000 and 2001, respectively.) This year, the clearances constituted a drop from the previous month, when the industry obtained a record 40, although October was a tough act to follow.

The devices cleared in November were spread across the major categories: X-ray and MR accounted for six; image management for five; nuclear medicine and radiotherapy for three each; and CT and ultrasound for two each. For the first time since DI SCAN began tracking FDA clearances, one of the cleared devices did not match a standard category. My Breast Friend from MBF Sales (Rockville, MD) is an aid for performing breast self-examination.

With few exceptions, the sophistication of the devices cleared in November set this month apart. Often a majority of the products cleared for commercialization are components or accessories, such as ultrasound transducers or MR coils. But most of the 28 devices cleared in November 2002 were major systems. Even many of the subsystems were substantial, such as the MR breast coil from USA Instruments (Aurora, OH) built for Hitachi's 0.7T Altaire. The coil features a disposable biopsy plate. Also notable were an eight-channel neurovascular coil built by Medrad (Indianola, PA) for use with 1.5T GE scanners; Siemens' proprietary six-channel body coil for its high-field systems; a torso array from W.L. Gore for use on GE 3T scanners; and Toshiba's proprietary parallel acquisition technology, called Speeder.

The Innova 4100 from GE Medical Systems (Waukesha, WI) was among the major FDA clearances featured on the RSNA show floor. The detector is a 41 x 41-cm, single-piece, nontiled sheet of amorphous silicon built into a three-axis gantry positioner with a tableside user interface.

The primary technological difference between this system, commercially launched at the last RSNA meeting, and the Innova 2000 is the size of the panel. The detector built into the Innova 4100 covers about twice the area of the 20 x 20-cm detector onboard Innova 2000, the company's first flat-panel x-ray system. Applications for the two GE devices differ in direct correlation to the size of their panels. The relatively small detector area in the Innova 2000 constrains this device to cardiac imaging. The much larger detector in the Innova 4100 supports interventional vascular applications.

Clinical studies cited as support for GE's FDA application included a comparison by six radiologists at three hospitals of images taken using the Innova 2000 and 4100. Participating in the study were St. Luke's Hospital (Bethlehem, PA), St. Francis Hospital (Peoria, IL), and Centre Paris Nord (Sarcelles, France). The same group of radiologists clinically evaluated the diagnostic quality of the images produced using the Innova 4100. The product's fluoroscopic capabilities were evaluated under clinical conditions by three radiologists at St. Luke's Hospital.

Data submitted to the FDA were designed to demonstrate "substantial equivalence" to a previously marketed device, in this case the Innova 2000. But at the RSNA meeting, the company emphasized data demonstrating the clinical advantages of the system over conventional systems based on image intensifiers. Based at least partly on feedback from radiologists who used the Innova 4100 prior to its commercial launch, GE forecast the installation of 100 units in 2003.

Philips Medical Systems (Best, the Netherlands) featured flat-detector technology for its Integris Allura vascular system, and Canon Medical (Tokyo, Japan) showcased a new digital radiography detector. Both obtained FDA clearances in November.

Philips received Nov. 22 a supplementary clearance for its Integris Allura, a cardiovascular system with an amorphous silicon flat detector that cleared the FDA some eight months earlier. (At its RSNA booth, the company showed a work-in-progress, large field-of-view flat detector for noncardiac angiographic studies that Philips executives described as similar to GE's Innova 4100.)

Canon received FDA clearance eight days before the exhibit opened on its new CXDI-40G, an amorphous silicon-based detector. The company's latest technology works in conjunction with an upright stand, table, or universal stand. Its predecessors are much more limited: The CXDI-11 works only with an upright stand, while the CXDI-22 operates only in conjunction with a table.

The CXDI-40G owes its flexibility to single-tile fabrication and miniaturized electronics that reduce the size of the product, while delivering the same image size, pixel pitch, and number of pixels as previously developed detectors. The CXDI-40G measures 550 x 550 x 68 mm, compared with 604 x 645 x 73.5 or 69 mm for the CXDI-22 and 552 x 598 x 231 mm for the CXDI-11. The newest detector also uses a removable fixed grid, whereas the other detector models use moving grids. Version 5.0 software, which accompanies the latest detector, includes improved control and changes in the interface compared with version 4.1.

A six-slice scanner from Siemens Medical Solutions (Erlangen, Germany) was the most noteworthy of the CT clearances conferred in November. Siemens featured the new scanner, dubbed Somatom Emotion 6, at the RSNA meeting as the flagship of its midtier CT family, topping the Emotion Duo and Emotion 4. The Emotion 6 received FDA clearance Nov. 22.

Toshiba America Medical Systems (Tustin, CA) highlighted its cardiac function analysis software, which also cleared the FDA Nov. 22. The software package is designed to postprocess cardiac CT images on the display console of Toshiba's multidetector scanners, semi-automatically calculating and displaying functional parameters. Among these parameters are end systolic and end diastolic volumes, stroke volume, left ventricular ejection fraction including peak filling and ejection rates, myocardial mass calculations, and regional wall motion display and analysis.

CTI PET Systems (Knoxville, TN) received FDA clearance three weeks ahead of the RSNA meeting for its Ecat LSO PET/CT 16. The dual modality scanner is a modified version of a hybrid using lutetium oxyorthosilicate cleared previously by the FDA. The major difference was the inclusion of a Sensation CT component that allows 16 slices per rotation versus the one or two slices possible with the Emotion CT previously configured with the PET technology. As with the earlier model, the 16-slice hybrid acquires PET data only in 3D mode. PET attenuation corrections are achieved using CT data.

The PET and CT components are contained within a single housing, which was modified cosmetically and enlarged to accommodate the increased size of the 16-slice CT gantry. The patient handling system was also modified to ensure adequate coverage for PET and CT scanning. The system is designed primarily for oncologic applications as a dual-modality scanner. The two modalities can be isolated, however, to allow separate PET or CT scans.

A separate FDA clearance was issued Nov. 25 to upgrade the patient handling system on all the company's hybrid scanners. The modification consists of two added foot switches and revised controller firmware that allow the system operator to raise or lower the bed in the scanner. This allows more accurate positioning of the patient in the field-of-view without having to retract the bed and patient completely from the scanner.

R2 Technology (Sunnyvale, CA) obtained FDA clearance Nov. 20 for a turnkey version of its computer-aided detection technology, ImageChecker, dedicated to the analysis of CT data. The system uses an off-the-shelf PC running either Windows or Linux. ImageChecker-CT adds CAD functionality to the standard functions of a radiology workstation, including the acquisition, storage, transmission, and display of images. Regions of interest are identified in 2D cross sections and 3D volumes of chest CT images for evaluation by radiologists. The system is designed to identify lung nodules that may be cancerous. The CAD algorithm also provides measurement and characterization information about lesions that might be used in making clinical decisions. At the RSNA meeting, R2 emphasized that the proprietary CAD technology allows detection of nodules in chest CT exams taken for any clinical indication--not just exams done as part of an effort to screen for lung cancer.

Preliminary clinical results reported at the RSNA meeting and obtained using prototypes of the ImageChecker-CT indicate sensitivity of greater than 90%, with two false positives per case. Additional clinical studies are under way in the U.S. and Europe to evaluate the ability of the CAD workstation to recognize and mark lung abnormalities. Evaluation sites include Johns Hopkins Medical Institutions (Baltimore), Palo Alto Medical Foundation (Palo Alto, CA), Brigham and Women's Hospital (Boston), St. Paul's Hospital (Vancouver, BC) the Hospital Pitie-Salpetriere (Paris), the University of Vienna, and the University of Rome.