FRACTAL ANALYSIS OF MAMMOGRAPHIC LESIONS - A PROSPECTIVE, BLINDED TRIAL

Mammography has become the mainstay of breast cancer screening. Howeve r, widespread mammography has led to an increase of the number of brea st biopsies done for benign disease. Therefore, a method to better dis criminate benign from malignant lesions is needed. Fractal analysis is a mathematical method which can quantify complex shapes. It has been previously shown retrospectively that the composite fractal dimensions , D, of malignant mammographic masses is higher than for benign lesion s. A prospective study of 75 patients who were recommended to undergo needle localized breast biopsy by independent radiologists had the com posite D calculated. Fractal analysis was done without knowledge of th e biopsy results. The mean composite D of malignant lesions was higher than benign lesions, 2.545 +/- 0.067 vs. 1.936 +/- 0.144 (p = 0.00004 ). Calculation of a receiver-operating characteristic curve showed tha t a cutoff value of 2.067 had a 100% sensitivity and 63% specificity ( i.e., false positive rate of 37%). Mean D for fibroadenomas was 2.087 +/- 0.054, fibrocystic disease was 1.877 +/- 0.167, DCIS was 2.261 +/- 0.069, and invasive cancer was 2.634 +/- 0.039 (1-way ANOVA, p = 0.00 007). These data imply that fractal analysis may be beneficial in disc riminating between benign and malignant lesions. However, further stud y in a larger number of patients with a variety of lesions is needed.