Arpad Bischof MD, Presenter: Employee, IMAGE Information Systems

Thobias Muller, Abstract Co-Author: Nothing to Disclose

Joerg Barkhausen MD, Abstract Co-Author: Nothing to Disclose

To analyse the impact of radiation dose, number of projections and projection angle on image quality and accuracy in digital breast tomosynthesis (DBT).

57 DBT data sets (25 projections, angle 50°) with malignant and benign mass lesions were included into the study. Off-line image reconstruction was performed using all projections, every second (13 projections, angle 50°) and every third (9 projections, 50°) projection as well as 13 central projections (angle 25°) and 9 central projections only (angle 16°). The DBT images with a slice thickness of 1 mm where independently evaluated by five radiologists. The readers evaluated the subjective image quality and assigned each reconstruction to a BI-RADS category. Both, image quality and discriminatory power, where compared for benign and malignant lesions for each reconstruction.

Compared to the standard of reference (full number of projections) DBT images based on every second projection showed a comparable discriminatory power between benign and malignant lesions; positive-predictive value of 45,7% versus 44,3%, negative-predictive value 91,1 % versus 92,7%. Despite good diagnostic performance, the subjective image quality of DBT image with reduced number of projections was rated lower compared to the reference. All other reconstructions using either 13 central projections with an angle of 25° or only 9 projections were inferior to the reference with regard to the diagnostic accuracy and the subjective image quality was rated lower compared to the approach using 13 projections with an angle of 50°.

For the detection and characterization of mass lesions DBT data sets using 13 projections with an angle of 50° can reduce the radiation exposure without decreasing the diagnostic accuracy.

New reconstruction schemes can further reduce the radiation dose in digital breast tomosynthesis.

Bischof, A, Muller, T, Barkhausen, J, Evaluation of Image Quality and Diagnostic Performance of Breast Tomosynthesis at Reduced Exposure Dose.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045677.html