Clinical Applications of a CT Window Blending Algorithm: RADIO (Relative Attenuation-Dependent Image Overlay)

Abstract

A methodology is described using Adobe Photoshop and Adobe Extendscript to process DICOM images with a Relative Attenuation-Dependent Image Overlay (RADIO) algorithm to visualize the full dynamic range of CT in one view, without requiring a change in window and level settings. The potential clinical uses for such an algorithm are described in a pictorial overview, including applications in emergency radiology, oncologic imaging, and nuclear medicine and molecular imaging.

A novel multiple-windows blending of CT images in red-green-blue (RGB) color space: Phantoms study

“…These representations cannot be accomplished using conventional window techniques. This novel method is different from the previous methods of AHE [18,19], CLAHE [20], and MAHE [21,22], and the previous multi-windows blending method proposed by Mandell et al [23,26], which combines multiple windows into a single grayscale image using their RADIO algorithm. In these previous methods, the pixel values representation may be inconsistent and can cause misinterpretation among practitioners.…”

“…Subsequently, multiscale adaptive histogram equalization (MA-HE) is proposed for automated simultaneous display of the full dynamic range of a CT image [21,22]. Recently, Mandell et al [23] developed a multiple-windows blending technique with their relative attenuation-dependent image overlay (RADIO) algorithm, which can display all HU value ranges in a single view without changing the WW and WL values. However, all previous techniques changed the standard appearance of tissues and may be confusing to radiologists.…”

Lesion measurement on a combined “all-in-one” window for chest CT: effect on intra- and interobserver variability

“…Typical challenges associated with CT images such as the huge dynamic range of the Hounsfield scale and the presence of strong pixel value transitions across different tissue types, have been addressed by a patented decomposition technique called Fractional Multiscale Processing®. This technique makes it possible to render all tissue types with a contrast-detail that is comparable to the original contrast-detail, whereas this is not possible with conventional blending techniques such as mentioned in [1, 7]. In blending techniques as described by Mandell et al the soft tissue image is used as a substrate which is modified in the Hounsfield subregions of the lungs and the bone by either pixelwise addition or replacement, respectively using Photoshop.…”

“…A combined window theoretically has the potential to accelerate the image review process, since there would be fewer images to read and evaluate. Furthermore, by combining different window settings, the relationship between abnormalities and surrounding structures can be more clear, for example the relationship between a pleural mass and the rib cage, mediastinal or vascular extension from a pulmonary mass, ... Mandell and colleagues described the possibilities for a combined window in the setting of emergency radiology, oncology and nuclear medicine [1]. In chest imaging, these authors demonstrated the possible role for evaluation of diseases that contiguously affect multiple compartments, including aggressive infections, metastatic cancer and penetrating trauma [2].…”

“…This idea is not new. Postprocessing techniques such as histogram equalization [3], nonlinear CT windows [4], adaptive histogram equalization [5] companding [6] and blending [1, 7], have been investigated in the past. In contradistinction, the AIO-window is a newly developed image processing technique, derived from a commercial multiscale enhancement software for digital X-rays (MUSICA™, Agfa Medical Imaging).…”