ICD-10-CM > R00-R99 > R90-R94 > R92 > R92.3 > R92.31 R92.31 Mammographic fatty tissue density of breast Non-Billable/Non-Specific Applicable To Breast density category within Imaging Reporting and Data System (BI-RADS): A Codes R92.311Mammographic fatty tissue density, right breastR92.312Mammographic fatty tissue density, left breastR92.313Mammographic fatty tissue density, bilateral breasts