secondary data set information is incorporated into a primary data set retaining a desired dynamic range and retaining the original primary set data quality . the secondary data set information is ‘ smuggled ’ into the least significant bits of the primary data set to result in an enhanced data set . if desired , the primary data word can be shifted toward the most significant bit . the enhanced data set may be viewed as if it were the original primary data set with existing playback devices , however it now includes additional ‘ smuggled ’ information which may be played back in coordination with the primary data set information . one example is flow - direction information ‘ smuggled ’ into an angiographic image . the least significant bits of the enhanced data words may be used to select the color map and color code the images . a user - adjustable intensity threshold can also be employed to select between color maps . information stored in this fashion results in a substantial savings in disk storage requirements . also , since the information of the primary and secondary data sets are merged into a single word , they will remain together throughout many different types of processing , such as maximum intensity projection in volumetric imaging .