Joint Department of Medical Imaging and Department of Radiation Oncology, Princess Margaret Hospital, Department of Pathology, and Division of General Surgery, University Health Network and Mount Sinai Hospital, University of Toronto, 610 University Ave, Toronto, ON, Canada M5G 2M9.
Radiology. 2010 Mar;254(3):747-54. doi: 10.1148/radiol.09090508. Epub 2010 Feb 1.
To analyze the direct relationship between complex internal magnetic resonance (MR) signal intensity (SI) patterns observed in colorectal liver metastases and their microscopic tissue characteristics.
The institutional ethics board approved this study. In seven consecutive patients undergoing hepatic resection for liver metastases (primary colorectal in six, breast mistaken for colorectal in one), the resected fresh ex vivo liver specimen was examined with T1-weighted (repetition time msec/echo time msec, 9/4.4-4.8) and T2-weighted (2500/90) MR imaging by using a voxel size of 0.47 x 0.7 x 2 mm. The liver was sectioned in a concordant plane, and individual histologic slides were scanned and reconstructed to form a whole-mount pathologic image of the metastases. A pathologist identified the regions of interest for intraacinar necrosis (IAN), loose or dense fibrosis, and moderately and poorly differentiated cells within the metastases, and these regions were matched to the corresponding MR image. The morphologic and SI patterns were noted. The normalized ratio between the SI of these regions and that of the background liver was determined on T1- and T2-weighted images. Pairwise differences between tissue types were calculated by using linear mixed model, with the P values adjusted for multiple comparisons by using the method of Sidak.
A total of 98 zones were defined after pathologic analysis. On T2-weighted images, IAN was significantly lower in SI (P < .05) than the other tissues types. On T1-weighted images, IAN was significantly higher in SI than the other tissues types (P < .001). The type of necrosis encountered in these specimens was exclusively IAN. Qualitatively IAN had a specific pattern of SI (hypointense on T2-weighted and hyperintense on T1-weighted images). Other tissues types, including fibrosis, showed a pattern of hyperintensity on T2-weighted and hypointensity on T1-weighted images.
IAN seen in colorectal metastases exhibits high T1-weighted SI and mixed T2-weighted SI. This SI pattern is unusual for common benign liver lesions and may be helpful in the MR imaging diagnosis of colorectal liver metastases. (c) RSNA, 2010.
分析结直肠肝转移瘤中观察到的复杂内部磁共振（MR）信号强度（SI）模式与肿瘤微观组织特征之间的直接关系。
本研究经机构伦理委员会批准。在 7 例连续接受肝切除术治疗肝转移瘤的患者中（原发性结直肠 6 例，误诊为结直肠 1 例），对新鲜离体肝标本进行 T1 加权（重复时间 msec/回波时间 msec，9/4.4-4.8）和 T2 加权（2500/90）MR 成像检查，体素大小为 0.47 x 0.7 x 2 mm。肝脏按一致的平面进行切片，对各个组织学切片进行扫描并重建，以形成转移瘤的整个载玻片病理图像。病理学家确定肿瘤内腺泡坏死（IAN）、疏松或致密纤维化以及中度和低度分化细胞的感兴趣区域，并将这些区域与相应的 MR 图像匹配。注意形态和 SI 模式。在 T1 和 T2 加权图像上确定这些区域的 SI 与背景肝脏 SI 的归一化比值。通过线性混合模型计算组织类型之间的差异，并用 Sidak 法调整多重比较的 P 值。
病理分析后共定义了 98 个区域。在 T2 加权图像上，IAN 的 SI 明显低于其他组织类型（P<.05）。在 T1 加权图像上，IAN 的 SI 明显高于其他组织类型（P<.001）。这些标本中遇到的坏死类型仅为 IAN。IAN 的 SI 具有特定的模式（T2 加权图像上呈低信号，T1 加权图像上呈高信号）。其他组织类型，包括纤维化，在 T2 加权图像上呈高信号，在 T1 加权图像上呈低信号。
结直肠转移瘤中的 IAN 表现出高 T1 加权 SI 和混合 T2 加权 SI。这种 SI 模式在常见的良性肝脏病变中不常见，可能有助于结直肠肝转移瘤的 MR 成像诊断。
