Step-oblique mammography

Step-oblique mammography is an accurate technique for determining whether a mammographic finding visible on multiple images on only one projection (but not elucidated using standard additional mammographic projections) represents a summation artifact or a true mass and for precisely localizing the true mass for further evaluation. 

The step-oblique mammography technique is an effective tool in the evaluation of patients who have densities visible just on one view. Projections are obtained every 15° beginning with the view in which the density is visible. If the density is still not visible with this technique, it can be considered a summation artifact, and no further evaluation is needed.

Technique

The diagnostic accuracy of step-oblique mammography will be maximized by carefully observing technical requirements.

• all step-oblique images should be taken with the breast in the same orientation (i.e. all mediolateral oblique or all lateromedial oblique)
• the nipple should be in profile on all step-oblique exposures and there should be no rolling of the breast .
• the patient should stand up straight during all step-oblique exposures.
• projections are obtained every 15° beginning with the view in which the density is visible

Clinical applications

• frequently used to assess the noncalcified density identified on only one standard mammographic projection
• helpful in evaluating grouped microcalcifications seen on only one standard view
• helped in establishing the presence of truly clustered calcific particles
• permitted accurate three-dimensional localization of the lesion
• step-oblique mammography is also useful in indicating the three-dimensional locations of more than one lesion in the same breast, especially if two or more lesions display similar mammographic features and are similar in distance from the nipple; confirmation of the precise three-dimensional location of each lesion by step-oblique mammography permits planning of the optimal approach for imaging-guided biopsy.
• if the density is not visible with this technique, it can be considered a summation artifact, and no further evaluation is needed

EtymologyHistory and etymology

It was initially described by K L Pearson et al 

See also

• mammographic view
• triangulation