High resolution CT mammography of surgical biopsy specimens

Our goal was to assess the performance of high resolution CT on breast biopsy specimens before considering the reevaluation of refined CT techniques in patients with breast abnormalities.

High resolution CT was done in 44 surgical biopsy specimens following conventional X-ray specimen mammography. The specimens comprised 38 palpable and nonpalpable soft tissue abnormalities with mean size of 19 mm and 6 specimens with clustered microcalcifications only. There were 21 carcinomas, 10 fibroadenomas, and 13 other benign conditions. Evaluation of CT and conventional images was done separately, and a feature-grading list was used to compare the two modalities.

In fatty specimens, grading of morphologic features of masses and the confidence to detect a soft tissue abnormality were equal with both techniques. CT significantly improved the confidence to detect a mass in 17 specimens with dense tissue: On a scale of 0-10, the mean score for detection was 3.8 with radiography and 5.8 with CT (p<0.008). For clustered microcalcifications, X-ray was superior to CT. The mean CT attenuation of 18 malignant masses (82 HU) was significantly lower than the mean attenuation of 10 fibroadenomas (131 HU; p = 0.003). CT scans of the American College of Radiology test phantom met the requirements for X-ray accreditation.

For soft tissue abnormalities, CT specimen mammography performed equally as or better than specimen radiography. These in vitro results suggest potential advantages for increased sensitivity and specificity with CT and justify further investigations.