Riverain Medical's bone suppression technology effective for lung nodule detection

Riverain Medical, an industry leader and innovator in computer-aided detection (CAD) and advanced visualization technologies, today announced the publication of a peer-reviewed observer study in the May 2011 issue of the American Journal of Roentgenology. The issue includes research performed at the University of Chicago Medical Center on the ability of radiologists to improve their detection of subtle lung nodules using chest X-rays aided by Riverain Medical's bone suppression technology. The study showed significant improvements in the physicians' performance in locating nodules when bone suppression technology was applied.

A major cause of missed lung cancers is the obstruction of a lung nodule by the ribs or clavicles on standard X-rays. In fact, in a series with 40 missed cancers, 95 percent of missed lung nodules were partly obscured by overlying ribs. The current study used Riverain Medical's SoftView bone suppression technology, developed to see if bone suppression can help improve early-stage lung cancer detection. SoftView uses patent pending machine learning and image processing algorithms to suppress the bone structures in the chest X-ray, giving the radiologist an un-obscured view of the lung's soft tissue.

The study used digital X-rays from 72 patients with subtle nodules and 79 patients without lung nodules. The average size of the nodules was 17.3 mm, and all images were taken from the Japanese Society of Radiological Technology nodule database. Three experienced radiologists participated in the study, using an independent test method with two image sets. The first image set (group A) included all 151 patients, with half (randomly selected) showing only the standard X-ray. The other half (group B) was shown the standard X-ray and the SoftView image. The second reading entailed the same subsets; however, group A was accompanied by bone suppression images, whereas group B only used the standard image. The radiologists indicated their selection by marking the position of the nodule and clicking their mouse on a confidence scale (ranging from 0-100). The results showed significant improvement when SoftView was used. The area under the ROC curves was significantly improved. The mean detection rate (correct localization) of the nodules improved from 60 percent with X-ray alone to 64 percent when SoftView was used. The authors note that "many of the subtle lung nodules were very difficult to detect on the standard chest radiographs but were relatively easy to detect on the bone suppression images." However, the rate of false positives was slightly increased using X-rays with bone suppression technology.

"Detecting lung cancer early is key to improving survival rates. The results of our study suggest that the use of bone suppression images can significantly improve detection of subtle lung nodules compared to the use of standard X-ray alone," said Heber MacMahon, MB, BCh, Professor of Radiology and Section Chief of Thoracic Radiology at the University of Chicago Medical Center. "Although the mean numbers of false positives were slightly increased, the more important result showed an increase in detection accuracy for lung nodules that were cancerous. We see bone suppression technology as another important tool for improving patient outcomes."

FDA-cleared in March 2010, SoftView is an innovative, patent pending, technology designed to increase the clarity of chest X-rays by suppressing bone. SoftView can be applied to every chest X-ray in the hospital without specialized imaging equipment, changes in imaging protocols or additional radiation dose to the patient. Using advanced bone suppression and image enhancement technology, SoftView automatically provides a soft tissue image for more confident image interpretations.

"By suppressing the ribs and clavicles, SoftView allows radiologists to see up to 40 percent more of the soft tissue," said Steve Worrell, chief technology officer of Riverain Medical. "By giving physicians a better view of the lungs, we are helping physicians find lung nodules sooner, providing the best opportunity to detect cancer at its earliest and most treatable stage."