Application of spectral CT imaging in evaluating lymph node metastasis in patients with gastric cancers: initial findings

Abstract

Background Traditional computed tomography (CT) can predict the lymph node metastasis of gastric cancers with moderate accuracy; however, investigation of spectral CT imaging in this field is still limited. Purpose To explore the application of spectral CT imaging in evaluating lymph node metastasis in patients with gastric cancers. Material and Methods Twenty-four patients with gastric cancers prospectively underwent spectral CT imaging in the arterial phase. The short and long diameters, material concentrations, and CT values were measured and compared between lymph nodes with and without metastasis. The diagnostic performance of the CT index in identifying metastatic lymph nodes was analyzed with receiver operating characteristic (ROC) analysis. Results A total of 102 lymph nodes (77 metastatic, 25 non-metastatic) were detected on spectral CT imaging with the reference of postoperative pathologic exanimation. The short and long diameters, water/fat concentrations, CT value, and ratio between lymph nodes vs. tumors of metastatic lymph nodes were significantly higher than those of non-metastatic ones (all P < 0.05). With a cut-off of 0.785, the CT ratio of lymph node/tumor on 70-keV monochromatic images yielded an accuracy of 81.4% in differentiating lymph nodes with and without metastasis. Conclusion Spectral CT imaging detects lymph nodes more clearly, and the CT ratio of lymph node/tumor on 70-keV monochromatic images holds great potential in differentiating lymph nodes with and without metastasis, which is more accurate than size measurement.

Detecting lymph node metastasis of esophageal cancer on dual-energy computed tomography

“…Studies have reported the role of dual-energy CT in assessing LN metastasis of neck and abdominal cancers ( 20 – 24 ). In the present study, we introduced material characterization and degradation functions and hypothesized that dual-energy CT improves the diagnostic accuracy of differentiating metastatic from non-metastatic LNs in patient with esophageal cancer.…”

Lysyl oxidase and hypoxia-inducible factor 1α: biomarkers of gastric cancer

“…These interventions do not improve prognosis, increase survival rate or prolong survival time[11]. In addition, there are disadvantages to current treatment methods, including inconvenience, increased prevalence of complications, and side-effects[12]. It has been reported that many factors are involved in the progression of GC.…”

能谱ct在胃癌术前分期中的研究现状

“…，提供 了新的诊断模式 [6,7] [8,9] 。目前，单能成像的研究 热点主要有小病灶的检出、优化图像质量、低对比剂及低辐 射剂量等方面。 多项研究表明 [10,11] ，单能量成像可以获得较常规混合能 量图像更高的病灶对比噪声比，更有利于小病灶的检出，且 单能图像噪声较低 [12,13] 。如今，能量成像的研究热点还有最 佳单能成像方面，目的在于寻求对比噪声比较高且图像噪声 较低的最佳单能水平，中国和国际上学者在最佳单能方面的 研究 [14,15] 表明最佳单能量图像可在不增加辐射剂量的前提下， 较常规混能图像明显提高病灶的对比噪声比、 降低图像噪声， 从而提高图像质量，特别是对于细小的血管及解剖结构的显 示具有重要的临床应用价值。也有研究者表明将具有不同特 点的单能图像融合， 融合后的图像既具有较高的对比噪声比， 又具有较低的图像噪声，能够清晰显示病灶的结构特征及周 围组织结构 [16] 。 研究表明 [17] [18] 能谱 CT 动脉期的碘伪彩图可通 过颜色差异提升视觉感官， 从而提高早期胃癌病灶的检出率。 也有学者发现 [19] ，早期胃癌和胃炎均会引起血管生成增多， 而动脉期的 NIC 对两者的鉴别存在一定限度。 [20] 。能谱曲线为物质的特征谱线，不同物质能谱 [21] 。但是，在常规 CT 图像中很难完整显示，尤 其是对于早期胃癌的诊断和浆膜层侵犯的评估，因此胃癌 CT 评估 T 分期的准确率还有待提高 [22] 。 以往主要通过 CT 影像征象区分各期，如通过"双轨征" 诊断早期胃癌；区分胃癌 T3 和 T4a 期的有效征象为浆膜层高 强化线征(如图 1 所示)，该征象主要与浆膜面受否受侵犯 有关 [23] 。研究表明 [24] ，与正常胃壁相比，胃癌浆膜外脂肪浸 润处的碘浓度较正常胃壁有一定程度提高，通过这种差别可 对胃癌的浸润情况进行初步判断。中国有学者 [25] 分析了胃癌 的浸润深度发现，在判断胃壁的浸润深度方面，能谱 CT 单 能量图像的准确率更高，可较好地满足胃癌 T 分期的相关要 求。另有学者 [26] [28] ， 其评估标准还有待进一步探讨和总结。然而，对于能谱 CT [29] 的研究结果发现其对术前淋巴结转移的诊断具有一定的临床应 用价值。以往有研究表明，能谱 CT 判断胃癌 N 分期的准确率 较常规 CT 高 19% [30] ，有学者研究发现 [31] ，利用能谱 CT 成像 中的 70keV 单能量的 CT 值来诊断胃癌淋巴结转移的准确率较 高，联合应用淋巴结 IC 值、NIC 值、长短径比值和能谱曲线 斜率可提高胃癌淋巴结转移诊断的准确性 [32,33] 。 中国学者许琦 [34]…”