in recent years , the field of radiology has advanced from reviewing films on a view box to a digital era with viewing on a computer monitor . the digital environment has opened the doors to new image processing techniques that have capitalized on the three - dimensional ( 3d ) datasets of computed tomography , magnetic resonance imaging ( mri ) , and positron emission tomography . for example , maximum intensity projection and volume rendering provide a two - dimensional representation of the 3d volume and can better define some complex anatomy ; however , these techniques are limited by overlapping structures1,2 ( figure 1 ) . in this paper , we will discuss several features of the depth 3-dimensional ( d3d ) augmented reality imaging system . the d3d user wears a headset , similar to that used in 3d gaming , which provides a separate image to each eye , yielding binocular disparity and depth perception.3 d3d also provides convergence of the eyes to a particular focal point of interest , tracks the individual s natural head movements , and provides corresponding images to each eye s display ; thus , an immerse environment is established . the d3d algorithm provides an enhanced discrimination of separated points in space that might otherwise appear to overlap when viewed by conventional methods . s enhanced visualization is accompanied by a joystick control system , similar to that of a pilot such that the radiologist can fly through the image while selecting objects of interest with a 3d cursor . while d3d technology can be applied to multiple types of radiological imaging , the specific focus in the article will be related to viewing of microcalcifications in mammography . breast cancer is one of the leading causes of death in women.4,5 mammography can detect suspicious microcalcifications associated with preinvasive or invasive cancers.6 while breast calcifications are extremely common , and can be present in up to 86% of mammograms,7 a minority of calcifications biopsied tend to be preinvasive or invasive cancers in asymptomatic patients . a linear and branching distribution of microcalcifications is suspicious for ductal carcinoma in situ ( dcis).8,9 standard mammographic views may not reveal the true linear and branching distribution due to a suboptimal viewpoint . from the wrong viewpoint , a linear distribution of calcifications can appear as an amorphous aggregate , leading to false negatives . on the other hand , depending on the angle of view , a cluster of calcifications can be wrongly interpreted to follow a linear pattern , causing false positives . consequently , full 3d viewing of a group of calcifications has the potential advantage of reducing both false negatives and false positives . to test this hypothesis , in the present study , we generated image sets from a simulated dataset of microcalcifications and evaluated the discrimination of a branched or linear pattern when viewed with d3d . a simulated 3d dataset of microcalcifications in a linear , branching pattern was created using a total of 34 voxels in a 646464 matrix by an in - house script , with each microcalcification being of the same size . using a cartesian coordinate system , the simulated 3d dataset was uploaded such that each microcalcification was assigned to a unique ( x , y , z ) voxel within the volume of interest and a total of 262,144 ( 643 ) voxels were created of which 34 were assigned the value of  1  to represent calcification displayed as a white pixel . all other voxels within the volume of interest were assigned the value of  0  to represent noncalcified tissue . an initial left eye viewing perspective was assigned an ( x , y , z ) position outside the volume of interest . from the left eye viewing perspective , a series of cones , each being defined by the cone angle  and the trajectory angles  and  , were sent into the volume of interest to record the highest voxel in its path , either a  0  or a  1  ( figure 2 ) . finally , the values recorded for each cone were displayed in the head display unit with a unique image sent to each eye such that binocular disparity and depth perception are achieved ( figure 3 ) . the number of cones for each eye viewing perspective is determined by factors including : size of the pixel array in the head display unit , acceptable latency time for the user , and the computer processor speed . after the initial left and right eye images are established ( figure 4a ) , a new image is provided to each eye display each time any of the following occurs : changing the interocular distance to provide greater binocular disparity ( figure 4b ) ; changing the angular field of view ( figure 4c ) ; volume of interest is translated or rotated ( figure 4d ) ; user rotates their head with roll , pitch , or yaw maneuvers , by translation or combination thereof ( figure 4e ) . depth perception is the ability to distinguish the relative distance of an object in one s visual field . depth perception requires binocular disparity , which is the difference in image location seen by the left and right eyes . the simulated data were viewed with the d3d system by the author ( ew ) , who is a board - certified radiologist with 11 years of experience in evaluating the distribution of the microcalcifications . using simulated data allows one to visualize differing orientations and gain an appreciation of the importance of 3d visualization from multiple viewing points in obtaining an accurate diagnosis . a simulated 3d dataset of microcalcifications in a linear , branching pattern was created using a total of 34 voxels in a 646464 matrix by an in - house script , with each microcalcification being of the same size . using a cartesian coordinate system , the simulated 3d dataset was uploaded such that each microcalcification was assigned to a unique ( x , y , z ) voxel within the volume of interest and a total of 262,144 ( 643 ) voxels were created of which 34 were assigned the value of  1  to represent calcification displayed as a white pixel . all other voxels within the volume of interest were assigned the value of  0  to represent noncalcified tissue . an initial left eye viewing perspective was assigned an ( x , y , z ) position outside the volume of interest . from the left eye viewing perspective , a series of cones , each being defined by the cone angle  and the trajectory angles  and  , were sent into the volume of interest to record the highest voxel in its path , either a  0  or a  1  ( figure 2 ) . finally , the values recorded for each cone were displayed in the head display unit with a unique image sent to each eye such that binocular disparity and depth perception are achieved ( figure 3 ) . the number of cones for each eye viewing perspective is determined by factors including : size of the pixel array in the head display unit , acceptable latency time for the user , and the computer processor speed . after the initial left and right eye images are established ( figure 4a ) , a new image is provided to each eye display each time any of the following occurs : changing the interocular distance to provide greater binocular disparity ( figure 4b ) ; changing the angular field of view ( figure 4c ) ; volume of interest is translated or rotated ( figure 4d ) ; user rotates their head with roll , pitch , or yaw maneuvers , by translation or combination thereof ( figure 4e ) . depth perception is the ability to distinguish the relative distance of an object in one s visual field . depth perception requires binocular disparity , which is the difference in image location seen by the left and right eyes . the simulated data were viewed with the d3d system by the author ( ew ) , who is a board - certified radiologist with 11 years of experience in evaluating the distribution of the microcalcifications . using simulated data allows one to visualize differing orientations and gain an appreciation of the importance of 3d visualization from multiple viewing points in obtaining an accurate diagnosis . when the author visualized the microcalcifications with a single viewing perspective , the microcalcifications were classified as a cluster , which is indeterminate for cancer ( figure 5a ) . when the author visualized the microcalcifications with d3d , the system was rotated and the microcalcifications were classified as a linear pattern ( figure 5b ) , which is suspicious for breast cancer . finally , the image was rotated further and the microcalcifications were classified as a branching pattern , which is highly suspicious for dcis breast cancer ( figure 5c ) . the d3d s augmented reality imaging technique is an extremely computationally demanding process that is operated only through the recent advances in computer processing and head display unit technology . using a simulated image , d3d achieves a higher level of convergence and improved human machine interface ( hmi ) to discriminate linear or branching calcifications . while conventional two - view mammography can not assign microcalcifications to a specific 3d coordinate system , digital breast tomosynthesis and dedicated breast computed tomography are able to provide 3d spatial localization ; thus , d3d can only be used for these types of breast imaging.1015 d3d suggests that the preferred method of looking at calcifications is a fly - through such that the radiologist can better appreciate the 3d pattern . dcis can be multifocal , with regional variation in the histologic grade that predicts the risk for progression to invasive cancer . therefore , it is crucial to identify and treat all areas of dcis for the best possible outcome . whether viewing with contiguous slices or volume rendering , characterizing the 3d pattern of microcalcifications can be extremely difficult because there is no depth perception and no convergence of the viewing perspectives to a focal point . d3d provides an immersive fly - through perspective such that a 3d map of the suspicious microcalcifications can be drawn and highlighted . beyond improving the display of microcalcifications , d3d holds promise for enhanced visualization and discrimination of malignant breast masses within a dense breast or behind areas of benign pathology or previous surgery . in addition , d3d can give the viewer the ability to  fly - around  a breast mass and highlight the change in the shape or volume of the mass before and after therapy , by comparing the current mass to a 3d  ghost  of the mass recalled from a pretreatment baseline . there is strong rationale to support the value of dynamic 3d view of a tumor mass throughout the course of therapy . while the efficacy of neoadjuvant chemotherapy ( nact ) in advanced breast cancer is known to correlate to tumor shrinkage,16 data from the recent investigation of serial studies to predict your therapeutic response with imaging and molecular analysis ( i - spy ) trial demonstrated the importance in breast tumor morphology . in this study , the particular phenotype of the breast tumor , such as  well - defined  margins or  multilobulated  appearance , correlated with the pathologic response to nact and contributed to the clinical recommendation for breast conservation therapy instead of mastectomy.17 in fact , the mri findings were a better predictor of pathological response to nact compared with clinical assessment.18 in addition to enhanced visualization of the changing 3d morphology of the tumor , d3d can also help make an accurate volume and shape comparison of the tumor at two or more time points as a quantitative measure of effectiveness of nact . in the current practice , shifts in patient position from scan to scan can change the position and orientation of a breast tumor , which obscures subtle differences between treatment cycles . d3d can register the image to a 3d grid that is tied to an anatomic reference point . proper position and orientation of the ghost images representing prior states of the mass can permit color - coding of the regions of the tumor that are expanding or shrinking with an automatic calculation of the volume of change . in addition to mammography , the d3d s augmented reality technique can be applied to many of the radiological subspecialties . in neuroradiology , characterization of a cerebral aneurysm s morphology , orientation , neck , and relationship to other vessels is extremely important in both follow - up and in surgical planning . d3d can facilitate understanding the interrelationship of comminuted fracture fragments to guide surgery and to accurately orient the placement of prosthetic joints . in pulmonary imaging , the depth perception by d3d may help to better identify , characterize , and follow - up pulmonary nodules . in virtual colonoscopy , the improved hmi may speed up the examination and offer improved lesion detection . for all of these applications , and others to be conceived , the fact that d3d technology can input conventional digital radiologic images will permit thorough and rapid side - by - side comparison with the current standards . new radiological advances such as additional mri sequences , new contrast agents , and thinner imaging planes are expanding the information presented to the radiologist . it is becoming impractical for the radiologist to scroll through hundreds of slices to evaluate each item on the checklist . there is a growing need to optimize presentation of radiological images in a practical manner , whereby the radiologist can view the whole volume of data at once . not only does d3d of the future offer such an improved visual display , but also it will provide nonvisual sensory information to the user , including auditory and tactile feedback . for example , mr elastography provides information on the stiffness of tissue and d3d s augmented reality presents this as a tactile response to the stiffness by a glove . d3d s augmented reality provides new opportunity for enhanced visualization and improved hmi , creating the potential for improved diagnosis and response to therapy . d3d is an augmented reality medical imaging system that provides stereoscopic 3d imaging with binocular disparity . furthermore , d3d provides hmi in the form of a gaming joystick to  fly inside  the image and view the 3d lesion from any angle . we have illustrated , using a simulated dataset of breast microcalcifications , how the d3d system can reveal a linear branching morphology that would have otherwise been invisible under conventional imaging . future testing of the d3d should be performed to determine the utility of the system in mammography and other radiological subspecialties .