A Comparison between FDG PET/CT, CT and MRI in Detection of Spinal Metastases and its Impact on Clinical Management

Abstract

The aim of this study was to compare thediagnostic value of combined F-18-FDGPET/CT, CT and MRI indetection of spinalmetastatic lesionsand their impact onmanagement of these patients. Patientsand methods: A total of 22 patients withbiopsy-proven malignancy were enrolled.All patients underwent spinal MRI andwhole body F-18-FDG PET/CTexaminations using standard techniques.The diagnostic capabilities of the imagingmodalities were compared in the samespinal field of view. F-18-FDG PET/CTand MRI findings were compared with theresults of biopsy or clinical / radiologicalfollow up for at least 12 months as thereference standards. Results: A total of214 vertebral lesions were detected in 22cancer patients based on combined clinicaland radiological follow up (FU), theselesions were divided into: 129 metastatic &85 benign lesions. Moreover these 22patients were divided into: 12 with spinalmetastases and 10 free from spinalmetastases. Both lesions & patients baseddata analysis showed a significant higherdiagnostic accuracy for the combined F-18-FDG PET/CT (98.5% and 94.5%)compared to MRI (86% and 68%) and CT(79.5% & 54.5%) respectively(P<0.05).The significant differencebetween F-18 FDG PET/CT andmorphological techniques were moreobvious on specificity indices rather thansensitivity indices in both lesion and patientbased analysis. On the other hand, MRIresults were superior to those of CT on bothlesions and patients data analysis. Onlesion-based analysis, the sensitivity,specificity, positive predictive value (PPV)and negative predictive value (NPV) for F-18 FDG PET/CT were 99%, 98%, 98% &99%, For MRI were 88.4%, 82.4%,88.4%and 82.3%, and for CT were 83.7%, 73%,82.4 and 74.5% respectively. On patientbased analysis the sensitivity andspecificity for F-18 FDG PET/CT were100% & 90% compared to 75% &60% inMRI and 66.6% &40% in CT (P<0.05).The relative superiority of the F-18 FDGbased technique compared to themorphological techniques in respect tosensitivity and specificity providesignificant changes in patient managementin 27.2 % & 41% of cases compared to MRI& CT respectively.Conclusion: Combined F-18 FDGPET/CT scan showed the highest utmostsensitivity, specificity and accuracyfollowed by MRI and lastly CT in the detection of spinal metastatic lesions.Consequently18F-FDG PET/CT has abetter impact on clinical managementcompared to MRI&CT