A prospective study of dual-energy computed tomography for differentiating metastatic and non-metastatic lymph nodes of colorectal cancer

Lin Qiu; Junjiao Hu; Zeping Weng; Sirun Liu; Guangyu Jiang; Xiangran Cai

doi:10.21037/qims-20-3

A prospective study of dual-energy computed tomography for differentiating metastatic and non-metastatic lymph nodes of colorectal cancer

Quant Imaging Med Surg. 2021 Aug;11(8):3448-3459. doi: 10.21037/qims-20-3.

Authors

Lin Qiu¹, Junjiao Hu¹, Zeping Weng², Sirun Liu¹, Guangyu Jiang², Xiangran Cai¹

Affiliations

¹ Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou, China.
² Pathology Department, The First Affiliated Hospital of Jinan University, Guangzhou, China.

Abstract

Background: Colorectal cancer (CRC) is the third most common malignancy worldwide, and lymph node metastasis is considered to be a risk factor for local recurrence and a poor prognosis in colorectal cancer. However, there remains a lack of reliable and non-invasive biomarkers to identify the lymph node status of CRC patients preoperatively. The purpose of this study was to explore the ability of dual-energy computed tomography (DECT) to differentiate metastatic from non-metastatic lymph nodes in colorectal cancer.

Methods: Seventy-one patients with primary colorectal cancer underwent contrast-enhanced dual-energy computed tomography imaging preoperatively. The colorectal specimen was scanned postoperatively, and lymph nodes were matched to the pathology report. The following dual-energy computed tomography quantitative parameters were analyzed: dual-energy curve slope value (λ_HU), standardized iodine concentration (n△HU), iodine water ratio (nIWR), electron density value (nρ_eff), and effective atom-number (nZ), based on metastatic and non-metastatic lymph node differentiation. Also, sensitivity and specificity analyses were performed using receiver operating characteristic curves.

Results: In all patients, one hundred and fifty lymph nodes, including 66 non-metastatic and 84 metastatic lymph nodes, were matched using the radiological-pathological correlation. Metastatic nodes had significantly greater λ_HU, n△HU, and nIWR values than non-metastatic nodes in both the arterial and venous phases (P<0.01). The area under curve (AUC), sensitivity, and specificity were 0.80, 80%, and 66% for λ_HU; 0.86, 70%, and 95% for n△HU; and 0.88, 71%, and 95% for nIWR in the arterial phase. There was no significant difference in electron density and effective Z values between metastatic and non-metastatic lymph nodes.

Conclusions: DECT quantitative parameters may help differentiate between metastatic and normal lymph nodes in patients with CRC.

Keywords: Computed tomography; colorectal cancer (CRC); dual-energy CT (DECT); lymph node; staging.