Apparent diffusion coefficient for lymph node characterization after chemoradiation therapy for locally advanced rectal cancer. (December 2015)

• Record Type: Journal Article
• Authors: Kim, Seung Ho; Ryu, Kyeong Hwa; Yoon, Jung-Hee; Lee, Yedaun; Paik, Jin Ho; Kim, Suk Jung; Jung, Hyun Kyung; Lee, Kwang Hwi
• Is Part Of: Acta radiologica. Volume 56:Number 12(2015 Dec.)
• Page Start: 1446
• Page End: 1453
• Publication Date: 2015-12
• Subjects: Diffusion-weighted magnetic resonance imaging -- apparent diffusion coefficient -- lymph node -- lymphatic metastasis -- rectum -- neoplasm; Radiology, Medical -- Periodicals; Radiography, Medical -- Periodicals; Radiotherapy -- Periodicals; 616.0757
• DOI: 10.1177/0284185114560936
• Languages: English
• ISSNs: 0284-1851

Abstract

Background: Because further treatment plans depends on lymph node (LN) status after neoadjuvant chemoradiation therapy (CRT), the accurate characterization of LN is important. Purpose: To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) for LN characterization after CRT and to compare the performance with that of LN size. Material and Methods: Fifty-three patients (36 men, 17 women; mean age, 58 years; age range, 34–79 years) who underwent CRT and subsequent surgery were included. All patients underwent 1.5-T magnetic resonance imaging (MRI). Each regional LN on post-CRT MRI was identified in consensus by two radiologists after reviewing the pre-CRT MRI. The ADC value and size in each LN was measured. To compare the mean ADC values and sizes of the metastatic and non-metastatic LNs after CRT, the t-test was used. To calculate the performance, a ROC curve analysis was performed. The histopathological examinations served as the reference standard. Results: A total of 115 LNs (29 metastatic and 86 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly higher than that of the non-metastatic LNs (1.36 ± 0.27 × 10 –3 mm 2 /s; 1.13 ± 0.23 × 10 –3 mm 2 /s, P < 0.0001). The mean size of the metastatic LNs was also significantly larger than that of the non-metastatic LNs (5.6 ± 3.1; 3.9 ± 1.2, P = 0.0078). There was no significant difference between the areas under the curve of the ADC and size (0.742 [95% CI, 0.652–0.819]; 0.680 [0.586–0.764], respectively, P = 0.4090). Conclusion: The performance of ADC for LN characterization after CRT was comparable to that of LN size.