Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
Department of Radiology, Sheba-Medical-Center, Ramat-Gan, Israel.
J Magn Reson Imaging. 2021 Jun;53(6):1913-1925. doi: 10.1002/jmri.27489. Epub 2020 Dec 26.
Diffusion-weighted imaging (DWI) can improve breast cancer characterizations, but often suffers from low image quality -particularly at informative b > 1000 s/mm values. The aim of this study was to evaluate multishot approaches characterizing Gaussian and non-Gaussian diffusivities in breast cancer. This was a prospective study, in which 15 subjects, including 13 patients with biopsy-confirmed breast cancers, were enrolled. DWI was acquired at 3 T using echo planar imaging (EPI) with and without zoomed excitations, readout-segmented EPI (RESOLVE), and spatiotemporal encoding (SPEN); dynamic contrast-enhanced (DCE) data were collected using three-dimensional gradient-echo T weighting; anatomies were evaluated with T -weighted two-dimensional turbo spin-echo. Congruence between malignancies delineated by DCE was assessed against high-resolution DWI scans with b-values in the 0-1800 s/mm range, as well as against apparent diffusion coefficient (ADC) and kurtosis maps. Data were evaluated by independent magnetic resonance scientists with 3-20 years of experience, and radiologists with 6 and 20 years of experience in breast MRI. Malignancies were assessed from ADC and kurtosis maps, using paired t tests after confirming that these values had a Gaussian distribution. Agreements between DWI and DCE datasets were also evaluated using Sorensen-Dice similarity coefficients. Cancerous and normal tissues were clearly separable by ADCs: by SPEN their average values were (1.03 ± 0.17) × 10 and (1.69 ± 0.19) × 10 mm /s (p < 0.0001); by RESOLVE these values were (1.16 ± 0.16) × 10 and (1.52 ± 0.14) × 10 (p = 0.00026). Kurtosis also distinguished lesions (K = 0.64 ± 0.15) from normal tissues (K = 0.45 ± 0.05), but only when measured by SPEN (p = 0.0008). The best statistical agreement with DCE-highlighted regions arose for SPEN-based DWIs recorded with b = 1800 s/mm (Sorensen-Dice coefficient = 0.67); DWI data recorded with b = 850 and 1200 s/mm , led to lower coefficients. Both ADC and kurtosis maps highlighted the breast malignancies, with ADCs providing a more significant separation. The most promising alternative for contrast-free delineations of the cancerous lesions arose from b = 1800 s/mm DWI. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 3.
扩散加权成像（DWI）可以提高乳腺癌的特征描述能力，但通常受到图像质量的限制，尤其是在信息量较大的 b 值（> 1000 s/mm）时。本研究旨在评估多shot 方法在乳腺癌中描述高斯和非高斯扩散系数的能力。这是一项前瞻性研究，共纳入 15 名受试者，包括 13 名经活检证实的乳腺癌患者。DWI 在 3T 上使用带有和不带有放大激发的平面回波成像（EPI）、读出分段 EPI（RESOLVE）和时空编码（SPEN）进行采集；使用三维梯度回波 T 加权进行动态对比增强（DCE）数据采集；使用 T 加权二维涡轮自旋回波评估解剖结构。使用 b 值在 0-1800 s/mm 范围内的高分辨率 DWI 扫描以及表观扩散系数（ADC）和峰度图来评估与高分辨率 DWI 扫描的一致性。具有 3-20 年经验的独立磁共振科学家和具有 6 年和 20 年乳腺 MRI 经验的放射科医生对数据进行了评估。使用配对 t 检验确认这些值具有高斯分布后，从 ADC 和峰度图评估了恶性肿瘤。还使用 Sorensen-Dice 相似系数评估了 DWI 和 DCE 数据集之间的一致性。ADC 可清晰区分癌症和正常组织：使用 SPEN 时，平均值分别为（1.03±0.17）×10 和（1.69±0.19）×10 毫米 /秒（p<0.0001）；使用 RESOLVE 时，平均值分别为（1.16±0.16）×10 和（1.52±0.14）×10（p=0.00026）。峰度也能区分病变（K=0.64±0.15）和正常组织（K=0.45±0.05），但仅在使用 SPEN 测量时（p=0.0008）。与 DCE 标记区域具有最佳统计学一致性的是使用 b=1800 s/mm 记录的基于 SPEN 的 DWI（Sorensen-Dice 系数=0.67）；使用 b=850 和 1200 s/mm 记录的 DWI 数据导致较低的系数。ADC 和峰度图均突出显示了乳腺恶性肿瘤，而 ADC 提供了更显著的分离。来自 b=1800 s/mm DWI 的无对比描绘癌症病变的最有前途的替代方法出现了。证据水平：2。技术功效分期：3。
