Assessment of Breast Cancer Risk with High Spectral and Spatial Resolution MRI

描述(由申请人提供)：我们建议测试HISS MRI是否比传统的脂肪抑制MRI和X光乳房X光检查更准确地估计乳腺癌风险。可靠的乳房密度测量是乳腺癌最强大的独立风险因素之一，可以显著改善风险管理和预防性治疗。X光乳房X光检查预测了总体癌症风险的增加，但由于实质和脂肪分离的错误以及实质体积的测量错误，对指导个别患者的治疗的价值有限。核磁共振成像可以对乳房实质进行3D成像，并检测水和脂肪的独立信号。MRI检测到由于他莫昔芬和雷洛昔芬导致的乳房密度显著降低。然而，传统的磁共振成像需要抑制来自乳房脂肪的信号。脂肪抑制有时是不均匀的，脂肪抑制脉冲影响水的共振，降低了实质体积测量的准确性。因此，我们提出了一种测量乳腺癌风险的创新方法：我们将使用高光谱和空间分辨率磁共振成像(HISS MRI)可靠地分离水和脂肪信号，并定量测量实质密度和他莫昔芬引起的乳腺密度变化。我们假设使用定量HISS成像将减少变异性，标准化测量，并提高对实质体积变化的敏感度。此外，基于对HISS图像和脂肪分布的HISS图像增强纹理的新的计算机辅助诊断(CAD)分析，HISS可能提供新的风险标记物。这项建议建立在这个实验室的工作基础上，该实验室在临床磁铁上实施了HISS MRI，并展示了这种方法的显著优势。我们提出了以下具体目标：目标1：利用HISS MRI对乳腺实质密度和形态进行全双侧定量测量。附着在乳房上的模体将被用来精确测量MRI可检测到的质子密度。新的软件将评估实质体积和纹理。脂肪的分布和组成将作为风险的额外标志进行测试。目的#2.比较HISS和传统方法：我们将比较HISS、常规脂肪抑制MRI、Dixon MRI方法和X光乳房X光摄影测量的乳腺密度。乳房密度的测量将包括绝对和部分实质体积，以及MRI可检测到的水质子密度。我们将比较HISS和常规MRI测量的可变性。目的#3.测量选择性雌激素受体调节剂(SERM)治疗后实质密度的变化：作为HISS MRI对乳腺癌风险变化的敏感性的测量，我们建议对已知可降低风险的预防性治疗进行成像反应。我们将比较HISS MRI对他莫昔芬治疗效果的敏感性，以及2D X线乳腺摄影和常规MRI的敏感性。

DESCRIPTION (provided by applicant): We propose to test whether HiSS MRI estimates breast cancer risk more accurately than conventional fat- suppressed MRI and X-ray mammography. Reliable measurements of breast density, which is one of the strongest independent risk factors for breast cancer, could significantly improve management of risk and preventive treatment. X-ray mammography predicts increased cancer risk on a population basis but has limited value for guiding treatment of individual patients, due to errors in separation of parenchyma and fat, and errors in measurement of the parenchymal volume. MRI allows 3D imaging of breast parenchyma and detects independent signals from water and fat. MRI detects significant decreases in breast density due to tamoxifen and raloxifen. However, conventional MRI requires suppression of signals from fat in the breast. Fat suppression is sometimes non-uniform and fat suppression pulses affect the water resonance, reducing the accuracy of parenchymal volume measurements. Therefore we propose an innovative approach to measurement of breast cancer risk: We will use high spectral and spatial resolution MR imaging (HiSS MRI) to reliably separate water and fat signals, and to quantitatively measure parenchymal density and changes in breast density due to tamoxifen. We hypothesize that use of quantitative HiSS imaging will reduce variability, standardize measurements, and increase sensitivity to variations in parenchymal volume. In addition, HiSS may provide new markers for risk based on the novel computer-aided diagnosis (CAD) analysis of the enhanced texture of HiSS images, and HiSS images of fat distribution. This proposal builds on work in this laboratory that implemented HiSS MRI on clinical magnets and demonstrated significant advantages of this approach. We propose the following Specific Aims: Aim #1: Implement quantitative full bilateral measurements of breast parenchymal density and morphology with HiSS MRI. Phantoms attached to the breast will be used to accurately measure MRI- detectable proton density. Novel software will evaluate parenchymal volume and texture. Fat distribution and composition will be tested as additional markers for risk. Aim #2. Compare HiSS with conventional approaches: We will compare breast density measured with HiSS, conventional fat-suppressed MRI, Dixon MRI methods, and X-ray mammography. Measures of breast density will include absolute and fractional parenchymal volume, and MRI-detectable water proton density. The variability of HiSS and conventional MRI measurements will be compared. Aim #3. Measure changes in parenchymal density due to selective estrogen receptor modulator (SERM) therapy: As a measure of the sensitivity of HiSS MRI to changes in breast cancer risk, we propose to image response to preventive therapy that is known to reduce risk. We will compare the sensitivity of HiSS MRI to effects of tamoxifen therapy with that of 2D X-ray mammography and conventional MRI.