Abstract P3-01-04: Potential clinical application of mammography conducted immediately after contrast enhanced CT as contrast enhanced subtraction mammography
Authors: Ohtani S , Yoshimura Y , Kin T , Fujihara M , Kajiwara Y , Ito M , Okada N , Urashima M 
Published: May 2019

Abstract
【Background】
Contrast Enhanced Subtraction Mammography (CESM) has gained worldwide popularity. It is said that CESM can not only identify tumors but also delineate high-density lesions of the mammary gland that are difficult to be identified by normal mammography (MMG), as well as intraductal progress, and tumor hemodynamics.
一In general, imaging is commenced two minutes after injection of the contrast medium, and is conducted in two directions, i.e., left to right craniocaudal view and mediolateral oblique view in the similar manner to the normal MMG.
【Subjects and purpose】
The study was performed upon the approval of the institutional review board, and included 70 patients who had undergone CESM during the nine-month period from August 2015 to April 2016 using the method that MMG was performed within 2-8 minutes after injection of the contrast medium during contrast enhanced computed tomography. The scan was performed as postoperative follow-up in 29 patients, and as preoperative testing in 41 patients. This method allowed us to obtain additional data with contrast imaging without placing financial burden on the patient, and we investigated whether this method was effective as CESM in the present study.
【Results】
Of the 41 patients who had undergone the scan as a preoperative test (bilateral scans in 3 patients, and 44 breasts), it was in 43 breasts (97.7 %) that lesions could be identified by MMG, and in 42 breasts (95.5 %) that lesions could be identified by CESM. Of the 44 breasts, three breasts showed high-density mammary glands, in two of which the mass was lateral to the margin of the mammary gland, and therefore could be identified by normal MMG; however, in one breast the mass was medial to the margin of the mammary gland and difficult to be identified by MMG, and could only be identified by CESM. The lesions in the two breasts that were difficult to be identified by CESM exhibited the histological type of DCIS, and the lesions were able to be identified as calcification with normal MMG.
The tumor diameter was compared using invasion size determined by CESM, contrast-enhanced MRI, and postoperative pathological specimen, respectively. The correlation coefficient for CESM and contrast-enhanced MRI was 0.9668, and the correlation coefficient for CESM and postoperative pathological specimen was 0.984887, with a strong correlation observed (Pearson's correlation coefficient test).
【Conclusion】
To the best of our knowledge, no reports of CESM in which MMG is performed immediately after contrast-enhanced CT have been published to date, and thus this is the world's first attempt of such method performed at our hospital. CESM ensures diagnosability without being invasive or placing financial burden on the patient. It was suggested that CESM can be clinically useful particularly for those who cannot undergo contrast-enhanced MRI due to hardware problems, financial difficulties, or metal embedded within the body.
Citation Format: Ohtani S, Yoshimura Y, Kin T, Fujihara M, Kajiwara Y, Ito M, Okada N, Urashima M. Potential clinical application of mammography conducted immediately after contrast enhanced CT as contrast enhanced subtraction mammography [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-01-04.