Thermoacoustic CT of the breast: pilot study observations

In order to assess the potential clinical utility of using thermoacoustic computer tomography (TCT) to image the breast, we conducted a retrospective pilot study of 78 patients. We recruited patients in three age groups (<40,40-50,>50 years). The study population was further segregated into normal and suspicious based on the results of the previous x-ray mammography and ultrasound. Image quality was evaluated qualitatively by consensus of two trained mammographers using a 4-point scale. The appearance of normal anatomy, cysts, benign disease and cancer was noted. Patients were also asked to rate the comfort of the TCT exam and to indicate a personal preference for x-ray mammography or TCT. Analysis of the data indicated that TCT image quality was dependent upon both patient age and breast density, improving with both increasing breast density and decreasing patient age. Fibrocystic disease was well seen, cysts appearing as areas of low RF absorption. Fibroadenomas did not demonstrate contrast enhancement with the exception of one patient with associated atypical hyperplasia. Cancer displayed higher RF absorption than surrounding tissues in 4/7 patients in whom cancer was confirmed, including one patient with a 7-mm ductal carcinoma in situ (DCIS).