BBI

While lung cancer is the No. 1 cancer killer in the U.S., the lack of emphasis on diagnosis and treatment of the disease has been highlighted in a variety of recent news stories, those stories focusing on the "stigma" of the disease associated with cigarette smoking. Also contributing to the apparent invisibility of the impact of lung cancer may be this disease's high rate of mortality, in part the result of the failure of the earliest possible detection of the first signs in the lungs, at a period when most treatable.

Clearly focusing on this issue are new systems that were rolled out last month during the 89th scientific assembly and annual meeting of the Radiological Society of North America (RSNA; Oak Brook, Illinois) in Chicago. Prominent among the new technologies designed to provide earlier detection of the first indicators of lung cancer are two new digital X-ray systems from GE Medical Systems (Waukesha, Wisconsin) and, from Siemens Medical Solutions (Malvern, Pennsylvania/Erlangen, Germany), the rollout of what it termed an enhanced computed tomography (CT) "lung viewing technology."

Currently, only 15% of lung cancers are detected in the early, most treatable stage, and more than 90% of lung cancers go undetected because they lie behind the ribs or bone, making them difficult to see on standard chest X-ray film, according to GE Medical.

Among a large number of technology rollouts at the meeting, GE Medical was addressing the earlier detection of lung cancer with its Dual Energy Subtraction system. The company terms Dual Energy Subtraction "a first-of-its-kind digital X-ray technology" designed to help doctors see "hidden" lung cancers by displaying a digital image of only the soft tissue in the chest, allowing a physician to better detect and diagnose this type of cancer, according to Andy Mack, Americas X-ray marketing manager for GE Medical. Key to the system is use of the company's Revolution Detector technology "capable of fast frame-rate acquisition," Mack told The BBI Newsletter. He said this allows "two exposures in rapid succession, less than two milliseconds apart . . . one at high energy, the other at lower energy." He says this technique provides the standard chest image and two additional images, one of the soft tissue, the other of the bone structure, which then can be separated to eliminate the skeletal image.

"Dual Energy Subtraction makes a significant difference in the evaluation and diagnosis of 15[%] to 20% of our cases," said Robert Gilkeson, MD, assistant professor of radiology and director of cardiothoracic imaging at University Hospitals of Cleveland and Case Western Reserve University School of Medicine (Cleveland, Ohio). "It is particularly valuable in distinguishing benign from malignant nodules, in addition to improving our analysis of other lung diseases such as asbestos plural disease," he added.

In addition to Dual Energy Subtraction, GE Medical unveiled a new computer-aided detection (CAD) technology, RapidScreen Digital CAD, that works with the company's digital X-ray system to assess chest images for 87 characteristics indicative of lung cancer. Mack explained that this system is similar to the "spellchecker" approach used in mammography CAD systems. Even if doctors are reviewing images for pneumonia or a broken rib, the RapidScreen system highlights areas suspicious of lung cancer for further analysis.

Approved by the FDA in 3Q03, RapidScreen offers a 20% improvement in sensitivity, Mack said, and can be used either with computed radiography or digital radiography systems.

The new lung viewing technology rolled out by Siemens at RSNA was syngo LungCARE, a system which the company calls the first technology of its kind FDA 510(k)-cleared and commercially available on the CT market. syngo LungCARE is designed to aid the physician in the visualization, evaluation and follow-up of pulmonary nodules and lesions, "and will set the benchmark in CT imaging of the lung," Siemens said.

The technology features nodule-enhanced viewing (NEV), a second-reader tool based on highly sensitive and clinically validated algorithms. syngo LungCARE is designed to improve visualization and workflow by providing automatic segmentation of physician-detected nodules, multiple viewing options for questionable areas and easy, customized reporting options. Using data from a high-resolution, low-dose CT examination of the thorax and special algorithms, detailed slice and 3-D images of the lungs are generated by the NEV system. Using these images, physicians can detect the smallest pulmonary nodules, possible precursors to lung cancer. Nodule volume and diameter then can be measured automatically.

Physicians also can view the images from any angle, enabling detailed evaluation. At the same time, syngo LungCARE CT allows previous CT examinations to be compared with the current examination. As a result, volume changes in individual pulmonary nodules are easy to detect. Details such as position, morphology and characteristic features of each pulmonary nodule are stored together with the images. All information, whether entered manually or generated automatically, is saved as an examination report in DICOM format.

New York University Medical Center (New York) has used syngo LungCARE technology for nearly two years since its initial development. "Enhanced patient care is made possible with advanced technologies, such as LungCARE," said David Naidich, MD, professor of radiology at NYU Medical Center. "Diagnosis of pulmonary nodules and lesions in an early stage of disease, combined with subsequent follow-up and treatment, has become a standard part of thoracic imaging," he added. "LungCARE markedly enhances our ability to identify and characterize parenchymal nodules, facilitating interpretation, especially of large data sets now available from state-of-the-art multi-detector CT scanners. The ability to find small lesions, in particular, prior to their recognition using standard CT imaging tools, may prove to be an especially valuable role for LungCARE by increasing survival rates for those with cancer."

Richard Hausmann, PhD, president of the CT Division of Siemens Medical Solutions, said LungCARE "will make a huge impact in the visualization and tracking of lung cancer. Having software to assist in finding lesions may lead to more sensitive and earlier physician's diagnosis and can positively influence patient treatment for improved outcomes."

R2 Technology (Sunnyvale, California) said the impact of CAD on the evaluation of chest CT exams was the focus of seven research papers being presented during RSNA. The developer of what it calls the only commercially available CAD system for use with chest multi-detector CT (MDCT) said these papers join "a growing body of research demonstrating the value of CAD technology that can improve radiologist accuracy and efficiency in interpreting these studies." One of the papers examined the potential benefit of CAD analysis of MDCT images. "What we found was that the ImageChecker CT CAD system found lesions of clinical significance, meaning they required surveillance or workup, in nearly a quarter of the cases originally interpreted as normal," said Kersten Peldschus, MD, of Brigham and Women's Hospital (Boston, Massachusetts). "The conclusion we have to draw from these results is that lung lesions with potential impact on patient management are missed at clinical interpretation of chest CT studies, but may be detected if CAD is used to assist the radiologist."

R2 said that several of the studies looked at the performance of radiologists when using CAD when reading MDCT chest exams, rates for lung nodule detection and the potential benefits of CAD for detecting actionable lung nodules in these exams. Other research concluded that the use of CAD integrated into an enhanced workstation improves the accuracy and efficiency of identifying lung nodules on thin-slice MDCT.