Abstract P3-01-01: Can synthetic 2D mammography be used to select patients in whom there is no need to review the digital breast tomosynthesis from which they were constructed? A review of 1871 consecutive mammogram sets of patients presenting symptomatically or for follow
Authors: Holt Simon DH , Moalla Ali , Williams Helen R , Nadi Khaldoun MY , Huws Anita M , Gurung Amrita , Thomas Daniel , Sharaiha Yousef M 
Published: May 2015

Introduction: A synthetic 2D mammogram can be created by combining the individual optimally enhanced 1mm slices of a digital breast tomosynthesis (DBT). Theoretically this could help overcome the problems associated with standard 2D mammograms (superimposition of structures hiding small cancers) and the significantly increased reading time and decreased conspicuity of microcalcifications associated with DBT. It may avoid the need for the double x-ray exposure required for combination 2D and DBT currently being suggested to maximise the specificity and sensitivity of mammography. The hypothesis we wished to test is, "if the synthetic 2D is normal, is there any advantage to looking at the DBTs as well?"

Method: We have reviewed 1000 consecutive cases presenting symptomatically or to our follow up clinic all of which underwent DBT on a Hologic Dimensions machine. From the 3D data sets synthetic 2D mammograms were constructed (Hologic C-view technology). One breast radiologist with 12 years experience of interpreting mammograms and more recently 4 years experience in interpreting DBTs was asked to first review the 2D synthetic mammograms (each breast CC and MLO) and report them before then reviewing the DBTs and issuing a final report. The mammograms were reported M1 to M5 using the standard BIRADs criteria. The BIRADs scores for each breast were recorded prospectively and entered into a database.

BIRADS Classification - Synthetic 2D v DBT  Synthetic 2D   M1M2M3M4M5 M16104000DBTM27109610210 M3013484 M4004210 M5002247Table 1

Results: 1000 consecutive patients were studied between October 2013 and March 2014. The average age of the women was 58.1 years (range 29 to 92). Of these some were under follow up after mastectomy so in total there were 1871 individual mammogram sets reported. Table 1 summarises the correlation between C-view and DBT reporting. The correlation between the two modalities is very close, but importantly there was only one patient in whom the C-view was reported normal or benign (M1 or M2) but the DBT reported a possible abnormality (M3). However, 31 cases reported as suspicious or malignant M3, 4 or 5 by C-view were subsequently downgraded to benign after review of the DBT.

Conclusion: In a symptomatic and follow up clinic, our study suggests that much radiologist’s time and x-ray exposure to the patient could be saved by using synthetic 2D mammograms derived from the DBT data rather than using separate 2D studies. Only if the C-view is reported M3, 4 or 5 is it necessary to review the DBT but for all these patients the DBT is already available without further x-ray exposure or recall.

Citation Format: Simon DH Holt, Ali Moalla, Helen R Williams, Khaldoun MY Nadi, Anita M Huws, Amrita Gurung, Daniel Thomas, Yousef M Sharaiha. Can synthetic 2D mammography be used to select patients in whom there is no need to review the digital breast tomosynthesis from which they were constructed? A review of 1871 consecutive mammogram sets of patients presenting symptomatically or for follow [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-01-01.