直肠癌的磁共振诊断

MRI Diagnosis of Rectal Carcinoma

目的 :分析直肠癌的MRI表现 ,评价MRI诊断直肠癌的价值。方法 :经手术病理证实的直肠癌患者 38例。术前均行MRI检查 ,使用安科 0 15PMRI仪 ,体线圈。扫描序列为SET1WI、T2WI和GRET2WI。结果 :MRI检出的阳性率为 96 .4 % (37 38) ,MRI确定病变向周围脂肪侵犯和淋巴结转移的准确性SE为 84 .2 % (32 38)和 81.6 % (31 38) ,GRE为 89.5 % (34 38)和 86 .8% (33 38) ,确定病变浸润邻近器官及骨盆的准确性SE为 89.5 % (34 38)和GRE为 92 .1% (35 38) ,确定病变分期的符合率SE序列为 6 3.2 % (2 4 38) ,GRE为 73.7% (2 8 38) ,两者结合为 78.9% (30 38)。肿瘤在SE序列T1WI等信号 ,T2WI稍高信号 ,GRE序列呈高亮信号 (与骨盆肌肉相比 )。结论 :MRI对直肠癌的诊断和分期有较大价值。两种序列对直肠癌的显示无明显差异 。

Objective: To analyze the MRI finding of rectal carcinoma and to evaluate its diagnostic value.Methods:Thirty eight patients (27 men and 11 women,aged 17～76 years) with rectal carcinoma were examined with MRI using body coil before surgery.The sequences used T1 weighted spin echo(T1W SE),T2 weighted spin echo(T2W SE),and T2 weighted gradient echo (T2W GRE).All 38 cases underwent surgery and the diagnosis was confirmed by pathologic examination.Results:The positive rate of rectal carcinoma by MRI was 96.4%(37/38). The accuracy rate of perirectal fat invasion, lymphnode metastasis, adjacent organ invasion on SE were 84.2%(32/38),81.6%(31/38), 89.5%(34/38), respectively; while on GRE, they were 89.5%(34/38), 86.8%(33/38),and 92.1%(35/38), respectively.The staging by MRI in this series was 63.2%(24/38) with SE and 73.7%(28/38) with GRE.Combination of the two sequences,however,showed an accuracy rate of 78.9% (30/38).The tumors were isointensity signal on SE T1WI,hyperintensity signal on SE,T2WI and sharp high intensity signal on T2W GRE,compared with intensity signal of pelvic muscle.Conclusion:MRI has high value in the diagnosis and staging of rectal carcinoma,compared with SE.GRE would not be superior in displaying rectal carcinoma.The combination of the two sequences could increase the accuracy rate of rectal carcinoma on MRI.