儿童后颅凹肿瘤的CT、MRI诊断

CT and MRI Diagnosis of Tumors in Midline Region of Children's Posterior Cranial Fossa

目的：分析儿童后颅凹常见肿瘤的ＣＴ和ＭＲＩ影像学表现，提高诊断该病的准确性。材料和方法：收集儿童后颅凹常见肿瘤４０例，其中髓母细胞瘤１８例，星形细胞瘤１３例，室管膜瘤９例。行ＣＴ和ＭＲＩ检查。ＣＴ平扫４０例，增强扫描３２例；ＭＲＩ平扫２８例，增强扫描１６例。将其结果与手术病理对照。结果：４０例儿童后颅凹常见肿瘤ＣＴ显示率为９７５％，ＭＲＩ显示率为１００％。术前ＣＴ定性误诊１１例，准确率为７２５％。术前ＭＲＩ定性误诊４例，准确率为８５７％。ＣＴ和ＭＲＩ联合检查，能对后颅凹多数常见肿瘤作出定位及定性诊断。ＭＲＩ能多方位成像，去除后颅凹颅骨伪影的干扰，对该病的定位定性诊断明显优于ＣＴ。结论：ＣＴ和ＭＲＩ检查相结合，能提高诊断儿童后颅凹常见肿瘤的准确率，为临床提供更准确的诊疗信息。

Purpose: To analyse CT and MRI characteristics of common tumors in the midline region of children's posterior cranial fossa and improve the diagnostic accuracy of the tumors. Materials and Methods: Z]Forty cases of common tumors (including medulloblastoma 18 cases, astrocytoma 13 cases, ependymoma 9 cases) in the midline region of children's posterior cranial fossa were performed by CT and/or MRI. CT plain scan was used in all 40 cases and 32 cases with contrast scan as well. MRI plain scan was used in 28 cases and 16 cases with enhanced scan. The imaging diagnosis were than compared with that of operation and pathology. Results: The CT and MRI positive rate for displaying these common tumors in the midline region of children's posterior cranial fossa were 97.5% and 100% respectively. The accuracy rate of CT diagnosis was 72.5% but 11 cases were misdiagnosed in preoperation. The accuracy rate of MRI diagnosis, however, was 85.7% with only 4 cases misdiagnosed in preoperation. CT combined with MRI, most common tumors in the midline region of children's posterior cranial fossa could be diagnosed accurately. MRI, with its directly multiple direction imaging capacity and no interference of bony artifact of posterior cranial fossa, was superior to CT in these tumors. Conclusion: Z]CT combined with MRI, improve the diagnostic accuracy of common tumors in the midline region of children's posterior cranial fossa and provide more information to the clinics.