Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Department of Veterinary Medicine & Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Med Phys. 2021 Nov;48(11):7323-7332. doi: 10.1002/mp.15245. Epub 2021 Oct 11.
Precise correlation between three-dimensional (3D) imaging and histology can aid biomechanical modeling of the breast. We develop a framework to register ex vivo images to histology using a novel cryo-fluorescence tomography (CFT) device.
A formalin-fixed cadaveric breast specimen, including chest wall, was subjected to high-resolution magnetic resonance (MR) imaging. The specimen was then frozen and embedded in an optimal cutting temperature (OCT) compound. The OCT block was placed in a CFT device with an overhead camera and 50 μm thick slices were successively shaved off the block. After each shaving, the block-face was photographed. At select locations including connective/adipose tissue, muscle, skin, and fibroglandular tissue, 20 μm sections were transferred onto cryogenic tape for manual hematoxylin and eosin staining, histological assessment, and image capture. A 3D white-light image was automatically reconstructed from the photographs by aligning fiducial markers embedded in the OCT block. The 3D MR image, 3D white-light image, and photomicrographs were rigidly registered. Target registration errors (TREs) were computed based on 10 pairs of points marked at fibroglandular intersections. The overall MR-histology registration was used to compare the MR intensities at tissue extraction sites with a one-way analysis of variance.
The MR image to CFT-captured white-light image registration achieved a mean TRE of 0.73 ± 0.25 mm (less than the 1 mm MR slice resolution). The block-face white-light image and block-face photomicrograph registration showed visually indistinguishable alignment of anatomical structures and tissue boundaries. The MR intensities at the four tissue sites identified from histology differed significantly (p < 0.01). Each tissue pair, except the skin-connective/adipose tissue pair, also had significantly different MR intensities (p < 0.01).
Fine sectioning in a highly controlled imaging/sectioning environment enables accurate registration between the MR image and histology. Statistically significant differences in MR signal intensities between histological tissues are indicators for the specificity of correlation between MRI and histology.
三维（3D）成像与组织学的精确相关有助于乳房生物力学模型的建立。我们开发了一种使用新型冷冻荧光断层扫描（CFT）设备将离体图像与组织学进行配准的框架。
对福尔马林固定的尸体乳房标本（包括胸壁）进行高分辨率磁共振（MR）成像。然后将标本冷冻并嵌入最佳切割温度（OCT）化合物中。将 OCT 块放入 CFT 设备中，使用顶置相机，然后从块上连续削下 50μm 厚的切片。每次削片后，都会拍摄块面照片。在包括结缔组织/脂肪组织、肌肉、皮肤和纤维腺体组织在内的特定位置，将 20μm 厚的切片转移到低温带上进行手动苏木精-伊红染色、组织学评估和图像采集。通过对准嵌入 OCT 块中的基准标记，自动从照片中重建 3D 白光图像。刚性配准 3D MR 图像、3D 白光图像和显微镜照片。基于纤维腺体交点处标记的 10 对点计算目标配准误差（TRE）。总体上，MR-组织学配准用于比较组织提取部位的 MR 强度与单因素方差分析。
MR 图像与 CFT 捕获的白光图像配准的平均 TRE 为 0.73±0.25mm（小于 1mmMR 切片分辨率）。块面白光图像和块面显微镜照片配准显示，解剖结构和组织边界的对齐具有视觉上无法区分的效果。从组织学中确定的四个组织部位的 MR 强度差异显著（p<0.01）。除了皮肤-结缔组织/脂肪组织对之外，每个组织对的 MR 强度也有显著差异（p<0.01）。
在高度受控的成像/切片环境中进行精细切片可以实现 MR 图像与组织学之间的精确配准。组织学组织之间的 MR 信号强度的统计学显著差异是 MRI 与组织学相关性特异性的指标。
