METHODS: Fifteen cases with locally advanced rectal cancer (LARC) followed by radical surgery after nCRT between September 2022 and February 2023 were recruited. Resected specimens were fixed in a perfluoropolyether-filled test tube and scanned with a 3.0T and 9.4T MRI system ex vivo. The residual tumor depth and MRI-based tumor regression grade (TRG) were subjectively assessed and then compared with the pathological findings.
RESULTS: The ex vivo 9.4T T2WI without fat suppression clearly differentiated tumor tissue, fibrosis and normal rectal wall, which clearly corresponded to the pathologic tissues of the rectal specimens. The TRG could be accurately assessed on ex vivo 9.4T images in 13/15 specimens (86.7%), while in 11/15 specimens (73.3%) on ex vivo 3.0T images.
CONCLUSIONS: Ex vivo 9.4T MR imaging clearly displayed the components of rectal wall and proved excellent diagnostic performance for evaluating the treatment response to nCRT, which allow radiologists to understand and then assess more accurately the TRG of LARC after nCRT.
方法:招募了2022年9月至2023年2月期间在nCRT后进行根治性手术的15例局部晚期直肠癌(LARC)患者。将切除的标本固定在全氟聚醚填充的试管中,并用3.0T和9.4TMRI系统进行离体扫描。主观评估残余肿瘤深度和基于MRI的肿瘤回归分级(TRG),然后与病理结果进行比较。
结果:无脂肪抑制的离体9.4TT2WI明显分化的肿瘤组织,纤维化和正常直肠壁,这清楚地对应于直肠标本的病理组织。在13/15标本的离体9.4T图像上可以准确评估TRG(86.7%),而在11/15标本(73.3%)的离体3.0T图像上。
结论:离体9.4T磁共振成像清楚地显示了直肠壁的组成部分,并证明了用于评估对nCRT的治疗反应的出色诊断性能,这使得放射科医生能够理解,然后更准确地评估nCRT后LARC的TRG。