SPECT/CT显像诊断脊柱单发转移瘤效能分析及有效辐射剂量评估

Diagnostic efficiency of SPECT/CT imaging in diagnosing solitary spinal metastasis and assessing effective radiation dosage

目的评价SPECT/CT显像对脊柱单发转移瘤的诊断效能并估算显像过程中患者所接受的有效辐射剂量。方法选择有恶性肿瘤病史且经核素全身骨显像检查发现疑似脊柱转移瘤单个椎体病灶的患者67例,对可疑椎体病灶行同机SPECT/CT显像,以病理学或6个月以上影像学(X线、CT、MRI或SPECT/CT)随访确诊结果为诊断标准,分别计算SPECT、CT图像及SPECT/CT图像诊断脊柱转移瘤的灵敏性、特异性、准确性、阳性预测值及阴性预测值,绘制ROC曲线评价SPECT、CT和SPECT/CT图像分析方法对脊柱单发转移瘤的诊断效能。计算行SPECT/CT检查时注入患者体内的放射性核素活度,记录同机螺旋CT检查时剂量长度乘积,估算SPECT/CT检查时放射性核素与同机CT所致患者接受的有效辐射剂量(以下称有效剂量)。结果 SPECT/CT显像诊断脊柱转移瘤的灵敏性、特异性、准确性、阳性预测值、阴性预测值分别为92.7%、88.5%、92.7%、88.5%、91.0%,均高于SPECT及CT单项检查。ROC曲线示对脊柱转移瘤诊断效能准确性最高的为SPECT/CT显像(AUC=0.950,P<0.01);其次为CT及SPECT。SPECT/CT检查时患者接受的有效剂量分别为(4.01±0.35)、(2.49±0.97)m Sv。结论SPECT/CT显像对脊柱单发转移瘤的诊断效能高于SPECT及CT单项检查。同机CT扫描可增加有效剂量。

Objective To evaluate the diagnostic efficiency of SPECT/CT in diagnosing indeterminate solitary spinal metastasis and assessing the effective radiation dosage .Methods A total of 67 patients with history of primary cancer who had solitary spinal lesions that could not be definitively diagnosed using ^99m Tc-MDP bone whole body scan were enrolled and SPECT/CT was performed.The pathological results or follow-up（≥6 months） results of X-ray, CT, MRI or SPECT/CT were the standards of final diagnosis .The sensitivity, specificity, accuracy, positive predictive value and negative predic-tive value of SPECT , CT and SPECT/CT imaging were calculated respectively , and the diagnostic efficiency of SPECT/CT imaging was assessed by using receiver operating characteristic （ ROC） analysis in diagnosing indeterminate solitary spinal metastasis.The injected radionuclide activity in patients was calculated for the SPECT /CT inspection, and the dose-length product（DLP） of spiral CT examination in the same machine was also assessed .During the SPECT/CT examination, the effective radiation dosage of radionuclide received in patients with the same machine CT was estimated （ hereinafter referred as the effective dose）.Results The sensitivity, specificity, accuracy, negative predictive value and positive predictive value for SPECT/CT imaging were 92.7%, 88.5%, 92.7%, 88.5%and 91.0%respectively, higher than that of SPECT and CT alone .The area under the ROC curve showed that SPECT/CT imaging had the highest diagnostic efficiency in diag-nosing indeterminate solitary spinal metastasis （AUC=0.950, P〈0.01）, and the following was CT and SPECT.The ef-fective doses were 4.01 ±0.35 mSv and 2.49 ±0.97 mSv when patients underwent SPECT/CT examination.Conclusions SPECT/CT imaging was more efficiency as compared with separate sets of SPECT and CT images .The effective radiation dose due to CT increases .