Interactive Detection, Evaluation and Classification of Breast Lesions from 4D MRI Using Direct Volume Visualization W.B. Carruthers*, K.R. Subramanian*, J.P. Brockway** *Dept. of Computer Science, UNC Charlotte, Charlotte, NC 28223 **Memory Testing Corporation, Davidson, NC 28036; Presbyterian HealthCare, Charlotte, NC 28207. Mammography is currently regarded as the most effective method for early detection of breast cancer, but recently its lower sensitivity in certain high risk cases has been less than desired. Preliminary investigation of these mammographically and ultrasonically occult lesions using high resolution MRI dynamic T1 weighted protocols suggests that it is possible to detect and characterize such tumors. Using inexpensive graphics hardware, we have developed interactive visualization tools to rapidly process, visualize and quantify lesions from 4D MRI (MRI volume + time). Our approach determines a confidence measure for each voxel, representing the probability that the voxel is part of the tumor, using a rough goodness-of-fit for the shape of the intensity-time curves. Our system takes advantage of readily available 3D texture mapping hardware to produce both 2D and 3D visualizations of the segmented MRI volume in real-time, allowing enhanced spatial perception of the tumor shape, size, distribution, and other characteristics useful in staging and treatment courses. Our tumor detection and visualization system permitted (1) volumetric analysis of lesions, (2) identification of shape characteristics, (3) tumor extent , (4) tumor size and (5) location of the four most common types of breast tumor, in mammographically and ultrasonically occult lesions in women who were at high risk. Figure Caption: 4D MRI Breast Tumor Segmentation revealing ductal cancer in situ and ductal cancer invasive. (Left) Coronal, Axial, Sagittal Slice views, (Right) 3D Volume Rendering.