Therapeutic response to radiofrequency ablation of neoplastic lesions: FDG PET/CT findings.
Ablation of neoplastic lesions by using radiofrequency energy is gaining popularity in clinical practice because of the minimally invasive nature of radiofrequency ablation (RFA). Primary and secondary tumors of the liver and lung are treated with RFA when surgery is precluded because of comorbidity. Benign bone tumors are also treated with RFA to relieve pain and prevent further tumor growth. Differentiation between postablation tissue changes and residual disease is difficult with morphologic imaging modalities such as ultrasonography, computed tomography (CT), and magnetic resonance (MR) imaging, thus limiting the use of these modalities to detection of residual disease early after RFA. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a functional imaging modality that can be used to study the effects and efficacy of RFA. Lesions that show increased FDG uptake at PET become completely photopenic immediately after RFA, a finding that is suggestive of the completeness of ablation. Focal areas of increased FDG uptake within the ablated zone are suggestive of residual disease. Reactive tissue changes such as inflammation are depicted in the periphery of the ablated lesion and show a uniform low-grade FDG uptake, which can be differentiated from the focal, nodular intense uptake in areas of residual disease. Use of combined FDG PET/CT to detect residual disease early after RFA allows ablation to be repeated, if necessary, to obtain the maximum therapeutic benefit. Note that FDG uptake in the complications sometimes associated with RFA can be a cause of potential false-positive PET results.
Bio-Imaging Unit, Tata Memorial Hospital, Dr Ernest Borges Rd, Parel, Mumbai 400012, India. nilpurandare@gmail.com
Nilendu C
NC
Purandare
Venkatesh
V
Rangarajan
Sneha A
SA
Shah
Anshu R
AR
Sharma
Suyash S
SS
Kulkarni
Aniruddha V
AV
Kulkarni
Sumeet G
SG
Dua
D001859:Bone Neoplasms / Q000175:diagnosis / Q000601:surgery*; D017115:Catheter Ablation; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000601:surgery*; D008175:Lung Neoplasms / Q000175:diagnosis / Q000601:surgery*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18