Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
Department of Medical Oncology, Radboud University Medical Center, Nijmegen, The Netherlands.
NMR Biomed. 2019 Jan;32(1):e4035. doi: 10.1002/nbm.4035. Epub 2018 Nov 20.
A relatively high signal for choline-containing compounds (total choline, tCho) is commonly found in H MR spectra of malignant tumors, but it is unclear if this also occurs in tumors in the liver. We evaluated the potential of the tCho signal in single voxel H MR spectra of the human liver to assess metastases of colorectal cancers.
MR spectra of an 8 cm PRESS-localized voxel were obtained at 3 T from the livers of 12 healthy volunteers and from metastatic lesions in 20 patients in two different sessions. To correct for motion artifacts, sequentially recorded spectra were individually phased and frequency aligned before averaging. Spectra were analyzed using LCModel and tissue levels estimated by water referencing. Repeatability was assessed with Bland-Altman analyses. To estimate tumor necrosis, diffusion-weighted imaging of the liver was performed. High resolution magic angle spinning (HRMAS) spectra of tumor and normal liver samples were obtained at 11.7 T.
With increasing tumor volumes, tCho levels decreased, indicating a partial volume effect. Mean tCho content in tumors larger than the PRESS voxel (>8 cm ) was significantly lower (p < 0.01) than for normal liver: 1.6 (range 0.0-3.4) versus 6.9 (range 4.9-11.1) mmol/kg wet weight, while it was comparable for tumors smaller than 8 cm : 7.0 (range 3.8-9.3) mmol/kg. The higher 90th percentile apparent diffusion coefficient value in the larger lesions indicates more necrosis. Measurement repeatability was average in normal livers and poor in tumors. HRMAS did not show substantial differences in choline-containing compounds between normal liver and metastasis.
An increased tCho content was not observed in H MR spectra of liver metastasis of colorectal cancer, compared with normal liver. This may be due to the background of a high tCho signal in spectra of normal liver or to an intrinsic lower tCho content in these tumors, but is most likely the result of necrosis in metastatic tumor tissue.
胆碱化合物（总胆碱，tCho）的相对高信号在恶性肿瘤的 H 磁共振波谱中很常见，但尚不清楚这种情况是否也发生在肝脏肿瘤中。我们评估了人肝脏单容积 H 磁共振波谱中 tCho 信号的潜力，以评估结直肠癌转移。
在 3T 下，从 12 名健康志愿者的肝脏和 20 名患者的转移病变中获得了 8cm PRESS 局部化体素的磁共振波谱。为了纠正运动伪影，依次记录的光谱在平均之前分别进行相位和频率对准。使用 LCModel 分析光谱，并通过水参考估计组织水平。使用 Bland-Altman 分析评估重复性。为了估计肿瘤坏死，对肝脏进行了扩散加权成像。在 11.7T 下获得了肿瘤和正常肝组织的高分辨率魔角旋转（HRMAS）光谱。
随着肿瘤体积的增加，tCho 水平降低，表明存在部分容积效应。大于 PRESS 体素（>8cm）的肿瘤中的平均 tCho 含量明显低于正常肝组织（p<0.01）：1.6（范围 0.0-3.4）与 6.9（范围 4.9-11.1）mmol/kg 湿重，而对于小于 8cm 的肿瘤，其值相当：7.0（范围 3.8-9.3）mmol/kg。较大病变中较高的 90th 百分位表观扩散系数值表明更多的坏死。正常肝脏的测量重复性平均，肿瘤的重复性差。HRMAS 未显示正常肝脏和转移瘤之间胆碱化合物的实质性差异。
与正常肝脏相比，结直肠癌肝转移的 H 磁共振波谱中未观察到 tCho 含量增加。这可能是由于正常肝脏波谱中 tCho 信号较高的背景，或者这些肿瘤中 tCho 含量固有较低，但最有可能是转移瘤组织坏死的结果。
