摘要
Objective:The primary aim of this study was to assess the efficacy of whole-body diffusion-weighted imaging(WB-DWI)in detecting tumour recurrence and metastasis of gastrointestinal cancers by comparison with 18F-2-fluoro-2-deoxy-Dglucose positron emission tomography or computed tomography(18F-FDG-PET/CT).A secondary aim was to evaluate the change of apparent diffusion coefficient(ADC)value between metastases and normal tissues.Methods:Twenty-eight previously confirmed gastrointestinal cancer patients with suspected tumour recurrence or metastasis were recruited.WB-DWI and PET/CT images were evaluated by two radiologists and a nuclear medicine physician.Agreement between WB-DWI and PET/CT for detective efficacy was compared using kappa statistics.Additionally,diagnostic accuracy,sensitivity,specificity,negative predictive value(NPV),and positive predictive value(PPV)were also statistically analysed.ADC values between metastatic and normal tissues were compared.Results:There was no statistically significant difference(P>0.05)in the overall diagnostic performances of PET/CT(accuracy 98.9%;sensitivity 95.2%;specificity 99.8%;PPV 98.9%;NPV 98.9%)and WB-DWI(accuracy 95.9%;sensitivity 81.7%;specificity 99.1%;PPV 95.0%;NPV 96.1%).WB-DWI showed agreement with PET/CT(j=0.877)for detecting recurrence and distant metastases.A statistically significant difference in ADC value was observed between tissues of normal healthy volunteers and metastases in lymph nodes,liver and bones(P<0.05).Conclusions:WB-DWI is reliable in detecting tumour recurrence and metastasis of colorectal cancer and offers the same diagnostic performance as 18F-PET/CT without ionizing radiation.The quantitative value of ADC provides extra information to determine cancer metastasis.
