Objectives: To determine association of gross tumour volume (GTV) of resectable oesophageal squamous cell carcinoma (SCC) measured on T2-weighted imaging (T2WI), contrast-enhanced T1-weighted imaging (CE-T1WI) and diffusion-weighted imaging (DWI) with T category and lymphatic metastasis (LM).
Methods: Sixty oesophageal SCC patients underwent fat-suppressed T2WI, CE-T1WI and DWI with b values of 0, 500 and 800 s/mm2. GTV was measured on three sequences. Statistical analyses were performed to determine association of GTV with T category and LM.
Results: Spearman's rank correlation analysis showed positive association of GTV with T category and LM (all p values < 0.01). Differences in GTV were found between T1 and T2 or T3 categories shown by Kruskal-Wallis H and one-way ANOVA tests, and between T1/T2 and T3 and between tumours with and without LM by Mann-Whitney U tests (all p values < 0.05). Receiver operating characteristic analyses showed cut-off GTVs of 5.795, 5.276 and 10.11 cm3 on CE-T1WI could better differentiate T1 from T2 categories, T1 from T3, and T1-2 from T3 than those of 7.066, 7.045 and 8.504 cm3 on T2WI, of 5.793, 6.609 and 6.989 cm3 on DWI with b value of 500 s/mm2, and of 4.156, 4.519 and 4.985 cm3 with b value of 800 s/mm2, respectively. Cut-off of 10.462 cm3 on DWI with b value of 500 s/mm2 could better identify LM than of 12.38, 8.793 and 9.600 cm3 on T2WI, CE-T1WI and DWI with b value of 800 s/mm2, respectively.
Conclusions: GTVs on T2WI, CE-T1WI and DWI are associated with T category of and LM of oesophageal SCC.
Key points: • GTV is associated with T category and lymphatic metastasis of oesophageal SCC • GTV measured on contrast-enhanced T 1 -weighted imaging better identifies T category • GTV measured on DWI with b value of 500 s/mm 2 better identifies lymphatic metastasis.
Keywords: Diffusion-weighted imaging; Lymphatic metastasis; Magnetic resonance imaging; Oesophagus; Squamous cell carcinoma.