锰增强磁共振成像诊断结直肠癌的初步实验研究

The Diagnostic Performance of Manganese-Enhanced Magnetic Resonance Imaging in Colorectal Cancer: a Preliminary Study

目的探讨锰增强磁共振成像(MEMRI)诊断结直肠癌的可行性。方法行结直肠癌细胞株SW620、DLD-1体外细胞摄锰磁共振成像检测,并以正常结肠黏膜上皮细胞为对照。行SW620、DLD-1细胞裸小鼠皮下移植,肿瘤最大径约5 mm、10 mm、15 mm时分别行磁共振成像。比较结直肠癌MEMRI与常规钆增强成像的表现,与病理对照。结果结直肠癌细胞株与正常细胞均摄取锰离子,癌细胞摄取更多。SW620、DLD-1摄锰后平均T1值缩短分别为正常细胞的4倍与2倍(P<0.05)。大部分移植瘤(17/23)在MEMRI均明显强化。不论钆或锰增强病灶均为不均匀强化方式,但钆增强不明显的病灶在锰增强上均明显强化且强化范围增大。锰增强上5 mm组明显强化的肿瘤数较10 mm与15 mm组多。结论 MEMRI不仅能强化大多数结直肠癌,还能明显强化常规钆增强不明显的病灶。此外,MEMRI可能适于检出较小病灶。

Objective To investigate the diagnostic performance of MEMRI in colorectal cancer. Methods The Mn uptake ability of colorectal cancer cell lines SW620 and DLD-1 were tested and compared with normal colon cell by MEMRI. Then the corresponding subcutaneous xenografts were developed on nude mice and the tumors underwent MRI at tumor sizes 5,10,15 mm respectively. The enhancement display was compared between gadolinium and manganese enhanced MRI. Results SW620 and DLD-1 cell lines took up more Mn2 ＋ than normal cell,which resulted in 4 and 2 times greater T1 value shortening than normal cell at in vitro MEMRI（ P〈 0. 05）. Most xenografts（ 17 /23） enhanced markedly on MEMRI. Heterogeneous enhancement pattern was invariably noted whether manganese or gadolinium agents were administered but on MEMRI tumors exhibited more evident enhancement and larger extent of enhanced area compared with Gd-enhanced MRI. The numbers of markedly enhanced cases were more in the 5mm group than in 10 and 15 mm group. Conclusion MEMRI was not only able to enhance colorectal cancers but had the potential to detect more cases of smaller lesions than larger ones and markedly enhance tumors compared to minimal Gd-enhancement.