Multiscale deformable registration for dual‐energy x‐ray imaging

Gang, Grace J.; Varon, Carlos A.; Kashani, Hany; Richard, Samuel; Paul, Narinder; Metter, Richard Van; Yorkston, J.; Siewerdsen, J. H.

doi:10.1118/1.3036981

Cited by 12 publications

(6 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Misalignments at finer scales were corrected using a normalized cross-correlation metric and diffeomorphic transform. This iterative hybrid registration approach is based on the multi-scale, deformable registration method for dual-energy X-ray images developed by Gang et al 62 and was used as we have previously reported. 18,63 Image processing for the DE subtraction was then performed using MATLAB (MathWorks, Natick, MA, USA).…”

Section: Dual-energy Mammography Imagingmentioning

confidence: 99%

Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

et al. 2016

View full text Add to dashboard Cite

Earlier detection of breast cancer reduces mortality from this disease. As a result, the development of better screening techniques is a topic of intense interest. Contrast-enhanced dual-energy mammography (DEM) is a novel technique that has improved sensitivity for cancer detection. However, the development of contrast agents for this technique is in its infancy. We herein report gold-silver alloy nanoparticles (GSAN) that have potent DEM contrast properties and improved biocompatibility. GSAN formulations containing a range of gold:silver ratios and capped with m-PEG were synthesized and characterized using various analytical methods. DEM and computed tomography (CT) phantom imaging showed that GSAN produced robust contrast that was comparable to silver alone. Cell viability, reactive oxygen species generation and DNA damage results revealed that the formulations with 30% or higher gold content are cytocompatible to Hep G2 and J774A.1 cells. In vivo imaging was performed in mice with and without breast tumors. The results showed that GSAN produce strong DEM and CT contrast and accumulated in tumors. Furthermore, both in vivo imaging and ex vivo analysis indicated the excretion of GSAN via both urine and feces. In summary, GSAN produce strong DEM and CT contrast, and has potential for both blood pool imaging and for breast cancer screening.

show abstract

Section: Dual-energy Mammography Imagingmentioning

confidence: 99%

Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Mutual information was not used at all in the temporal subtraction algorithm evaluated in this study, although mutual information has been used by others to register radiographic chest images. 26 The radiologic record of many patients contains images acquired at a number of time points from which multiple pairwise combinations may be used to construct a sequence of temporal subtraction images. Notable differences may be observed in such a sequence.…”

Section: Discussionmentioning

confidence: 99%

Temporal subtraction in chest radiography: Mutual information as a measure of image quality

et al. 2009

View full text Add to dashboard Cite

Purpose: Temporal subtraction is used to detect the interval change in chest radiographs and aid radiologists in patient diagnosis. This method registers two temporally different images by geometrically warping the lung region, or "lung mask," of a previous radiographic image to align with the current image. The gray levels of every pixel in the current image are subtracted from the gray levels of the corresponding pixels in the warped previous image to form a temporal subtraction image. While temporal subtraction images effectively enhance areas of pathologic change, misregistration of the images can mislead radiologists by obscuring the interval change or by creating artifacts that mimic change. The purpose of this study was to investigate the utility of mutual information computed between two registered radiographic chest images as a metric for distinguishing between clinically acceptable and clinically unacceptable temporal subtraction images. Methods: A radiologist subjectively rated the image quality of 138 temporal subtraction images using a 1 ͑poor͒ to 5 ͑excellent͒ scale. To objectively assess the registration accuracy depicted in the temporal subtraction images, which is the main factor that affects the quality of these images, mutual information was computed on the two constituent registered images prior to their subtraction to generate a temporal subtraction image. Mutual information measures the joint entropy of the current image and the warped previous image, yielding a higher value when the gray levels of spatially matched pixels in each image are consistent. Mutual information values were correlated with the radiologist's subjective ratings. To improve this correlation, mutual information was computed from a spatially limited lung mask, which was cropped from the bottom by 10%-60%. Additionally, the number of gray-level values used in the joint entropy histogram was varied. The ability of mutual information to predict the clinical acceptability of a temporal subtraction image was evaluated through receiver operating characteristic ͑ROC͒ analysis. Results: The mean correlation coefficient obtained between mutual information computed on constituent images and the subjective rating of temporal subtraction image quality was 0.785. ROC analysis yielded an average A z value of 0.852 for the ability of mutual information to distinguish between temporal subtraction images of clinically acceptable and clinically unacceptable quality. Conclusions:The results of this study establish a relationship between mutual information and temporal subtraction registration accuracy and demonstrate the ability of mutual information to objectively indicate the presence of misregistration artifacts.

show abstract

“…A normalized cross-correlation (CC) metric was then used with a diffeomorphic transform to correct for misalignment at finer scales. This iterative hybrid registration approach is based on the multi-scale, deformable registration method for dual-energy x-ray images developed by Gang et al [25]. For the purpose of display, all images were denoised by application of a 3×3 median filter, and the LE and HE images were unsharp masked to enhance anatomic details.…”

Section: Methodsmentioning

confidence: 99%

Development of silica-encapsulated silver nanoparticles as contrast agents intended for dual-energy mammography

et al. 2016

View full text Add to dashboard Cite

Objective Dual-energy (DE) mammography has recently entered the clinic. Previous theoretical and phantom studies demonstrated that silver provides greater contrast than iodine for this technique. Our objective was to characterize and evaluate in vivo a prototype silver contrast agent ultimately intended for DE mammography. Methods The prototype silver contrast agent was synthesized using a three-step process: synthesis of a silver core, silica encapsulation, and PEG coating. The nanoparticles were then injected into mice to determine their accumulation in various organs, blood half-life, and dual-energy contrast. All animal procedures were approved by the Institutional Animal Care and Use Committee. Results The final diameter of the nanoparticles was measured to be 102 (± 9) nm. The particles were removed from the vascular circulation with a half-life of 15 minutes, and accumulated in macrophage-rich organs such as the liver, spleen, and lymph nodes. Dual-energy subtraction techniques increased the signal difference-to-noise ratio of the particles by as much as a factor of 15.2 compared to the single-energy images. These nanoparticles produced no adverse effects in mice. Conclusion Silver nanoparticles are an effective contrast agent for dual-energy x-ray imaging. With further design improvements, silver nanoparticles may prove valuable in breast cancer screening and diagnosis.

show abstract

Multiscale deformable registration for dual‐energy x‐ray imaging

Cited by 12 publications

References 38 publications

Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

Temporal subtraction in chest radiography: Mutual information as a measure of image quality

Development of silica-encapsulated silver nanoparticles as contrast agents intended for dual-energy mammography

Contact Info

Product

Resources

About