Riverain's ClearRead Bone Suppression software improves detection of lung cancer

Riverain TechnologiesJun 23 2012

Software by Riverain Technologies significantly improves radiologists' ability to detect potentially cancerous lung nodules in X-ray images, and might be a cost-effective alternative to dual energy subtraction (DES) imaging, according to two new studies being presented at the 20^th Anniversary Meeting of the European Society of Thoracic Imaging (ESTI), June 22-24, in London.

Riverain's ClearRead Bone Suppression™ software uses machine learning algorithms to transform any conventional chest X-ray image into an enhanced, soft tissue image without the ribs and clavicles that sometimes obscure early lung cancer. DES also creates a soft tissue image but requires a dedicated dual energy imaging machine to form it. Depending on the methodology, DES may require two separate scans, thus exposing patients to more radiation than conventional X-ray. Riverain's computer-aided detection (CAD) software, ClearRead +Detect™, provides further support in decision making by circling suspicious areas on a bone-suppressed image that may be lung cancer. Final determination is made by the radiologist.

Riverain's Bone Suppression Technology is Comparable to DES

The first study, conducted at the Institute of Diagnostic, Interventional and Pediatric Radiology at the University Hospital Bern, Switzerland, compared Riverain's bone suppression and DES alone and in combination with CAD and found that Riverain's bone suppression software is as good as DES at detecting lung nodules while producing superior image quality.

In the retrospective study, three radiologists independently reviewed chest images of 143 patients: 101 patients with 155 lung nodules between 5-29mm previously confirmed using CT, and 42 subjects with no lung nodules. Each radiologist marked suspected nodules on each patient's original chest X-ray image, and individually on DES and bone-suppressed images with and without CAD.

The radiologists detected the most lung nodules in the bone-suppressed image with CAD markings. Their mean sensitivities - the percentage of the 155 lung nodules that were accurately identified - were: 46.9 percent using conventional X-ray only; 49.2 percent using a single-shot DES system; 49.7 percent using SoftView 2.0 (an earlier version of Riverain's ClearRead Bone Suppression); and 51.6 percent using SoftView 2.0 plus OnGuard 5.1 (an earlier version Riverain's ClearRead +Detect software). The overall diagnostic performance with the modalities was not significantly different.

"These findings are compelling results for hospitals, radiology practices and patients," said Steve Worrell, Riverain's Chief Technology Officer. "Radiologists detected as many lung nodules using Riverain bone suppression software on conventional X-ray images as they detected using a dedicated piece of imaging equipment that is more expensive, may expose patients to more radiation, and can only be used in the single location where it is housed. Our software immediately enhances any standard chest X-ray image, after capture, and can be used throughout entire healthcare systems without additional imaging equipment, staff or space requirements, and without any additional tests or radiation dose for patients."

The radiologists also gave the bone-suppressed images a significantly higher overall quality rating than the DES images. The true positive and false positive rates of these two modalities were statistically equivalent.

"Electronic bone suppression provides equivalent detection rates for lung nodules as DES, with better image quality, and might be a cost-effective alternative to DES chest radiography in the detection of lung nodules," said Zsolt Szucs-Farkas, M.D., Ph.D., chief investigator.

CAD and Radiologists Have Complementary Strengths

Dr. Szucs-Farkas also compared CAD markings before radiologist interpretation to the radiologists' findings. While CAD and the radiologists detected many of the same lung nodules, each also detected nodules the other did not find. CAD, on its own without any radiologist interpretation (assessed for research purposes only), accurately circled approximately 1 in 4 nodules that the radiologists missed, and the radiologists found approximately 1 in 3 nodules that CAD missed.

"Working together, radiologists and our CAD with bone suppression software bring different strengths to the table and significantly improve the detection of nodules that may be lung cancer using conventional chest X-ray," Worrell said.

Worldwide, lung cancer is the leading cause of cancer death in men and the second leading cause of cancer death in women.

Another Study Confirms Benefits of Riverain Bone Suppression Technology

A second study to be presented at ESTI 2012 again confirms Riverain's bone suppression software significantly improves radiologists' ability to detect lung nodules in chest X-ray images. Eight radiologists at Radboud University Nijmegen Medical Centre (RUNMC) and the Meander Medical Centre in Amersfoort, the Netherlands, reviewed chest X-ray images for 108 patients with a solitary CT-proven lung nodule and 192 patients without nodules. On average, they found 14.4 percent of lung nodules using Riverain's bone suppression technology (SoftView 2.4, now called ClearRead Bone Suppression) that were missed when they used conventional X-ray alone, without an increase in false positives. All individual readers improved detection with the help of the bone suppression software. Individual reader results ranged from as low as 52 percent without bone suppression to a high of 81 percent with the software. Average detection overall was 67 percent using X-ray alone, and 72 percent with bone suppression software.

"Multiple studies have shown that Riverain's bone suppression technology works for lung nodule detection," said researcher Steven Schalekamp, M.D., a Ph.D. student in the Department of Radiology of RUNMC. Schalekamp conducted the research under the supervision of Cornelia Schaefer-Prokop, M.D., Ph.D., a radiologist at Meander Medical Center, Amersfoort, the Netherlands. Dr. Schaefer-Prokop is a member of Riverain's medical advisory board.