Breast ImagingE1167. Eliminating the Enemy: Minimizing Background Parenchymal Enhancement Using Ultrafast Protocol MRI
Nagaraju A, Abe H, Schacht D, Kulkarni K, Sheth D. University of Chicago, Chicago, IL
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Background Information: Breast MRI has become a well-established modality in the detection and characterization of breast malignancy. Traditionally, breast MRI acquisitions entail unenhanced and enhanced imaging with temporally acquired dynamic images beginning at greater than 60 seconds after contrast administration. Although this approach has proven beneficial in the detection of malignancy, its clinical utility may be degraded by a multitude of factors such as background parenchymal enhancement (BPE) and motion artifact. As background parenchyma enhances, malignant enhancing lesions become less apparent to the radiologist. Furthermore, length of the MRI acquisition process increases the probability of motion artifact causing clinically significant degradation of the subtraction images. The true fast protocol is an accelerated MRI technique that obtains high temporal images within the first minute after contrast administration. The protocol specifics will be subsequently discussed. The true fast technique has proven to be comparable to traditional dynamic MRI in the differentiation of malignant from benign lesions by obtaining images within the immediate phase after contrast administration. At this time point, vascular malignant lesions have a much higher contrast uptake than benign normal background parenchyma, increasing the visibility of such lesions even in face of marked BPE. Additionally, the high temporal contrast of the ultrafast technique reduces motion artifact, as many sequences are performed in quick succession, decreasing the demand of motionlessness of the patient.
Educational Goals/Teaching Points: The goals of this exhibit are to understand the clinical utility, indications, and limitations of breast MRI including the true fast MRI protocol and how it differs from traditional breast MRI protocol. We will also focus on understanding how true fast breast MRI takes advantage of the enhancement characteristics of malignant lesions and develop search patterns and recognize pathologic disease on traditional and ultrafast breast MRI.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: True fast protocol MRI obtains T1 fat-suppressed imaging with high temporal resolution (every seven seconds starting 10 seconds after contrast administration over a 56-second period for a total of eight images). This differs from the commonly used traditional imaging strategy, which obtains the first image approximately one minute after contrast administration, then every 60–70 seconds henceforth, for a total of five images.
Conclusion: MRI is becoming an increasingly utilized modality in the screening of high-risk patients, diagnosis, and staging of breast malignancy. It supplements mammography and ultrasound well but has limitations, especially in patients with extreme BPE. The ultrafast breast MRI protocol strives to minimize this limitation with high temporal resolution imaging in the immediate phase after contrast administration to increase contrast differentiation between malignant lesions and BPE and also decrease motion artifact. Thus, this protocol may help decrease unnecessary procedures as specificity increases in MR evaluation of the breast.