Utility of I-124 PET/CT in identifying radioiodine avid lesions in differentiated thyroid cancer: a systematic review and meta-analysis.
BACKGROUND
Diagnostic I-123 scans have been shown to underestimate the disease burden in differentiated thyroid cancer (DTC) when compared to I-131 post-treatment scans, especially in children and patients who have had prior radioiodine (RAI) therapy and/or distant metastasis. I-124 PET/CT has been shown to be highly effective in imaging DTC-related metastatic disease.


METHODS
We performed a systematic review and meta-analysis of studies investigating the sensitivity and specificity of I-124 PET/CT in identifying lesions amenable to RAI therapy as confirmed by I-131 post-treatment scanning.


RESULTS
There were 141 patients and 415 lesions of DTC identified altogether. There was significant heterogeneity in the individual studies. The pooled sensitivity of the I-124 PET/CT in detecting lesions of differentiated thyroid cancer amenable to I-131 therapy was 94·2% (91·3-96·4% CI, P < 0·01), and the pooled specificity was 49·0% (34·8-63·4% CI, P < 0·01). The pooled positive likelihood ratio (LR) was 1·43 (1·05-1·94 CI), and the pooled negative LR was 0·28 (0·15-0·53 CI). Overall, the diagnostic odds ratio was 7·90 (3·39-18·48 CI). There were a small but increased number of lesions identified by I-124 PET/CT that was not detected on post-treatment scan.


CONCLUSIONS
I-124 PET/CT is a sensitive tool to diagnose RAI avid DTC lesions, but also detects some new lesions that are not visualized on the post-treatment I-131 scan. Further, carefully designed dosimetric studies may be required to fully establish the role of I-124 PET CT for identifying potential lesions for I-131 therapy. I-124 PET/CT in patients with DTC may have other applications in specific clinical situations.
Section of Nuclear Medicine, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Prasanna
http://orcid.org/0000-0003-4822-2705
P
Santhanam
Department of Nuclear Medicine, La Timone University Hospital & CERIMED & Inserm UMR1068, Aix-Marseille University, Marseille, France.
David
D
Taieb
Section of Nuclear Medicine, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Lilja
L
Solnes
Section of Nuclear Medicine, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Wael
W
Marashdeh
Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Paul W
PW
Ladenson
D006801:Humans; D007457:Iodine Radioisotopes; D000072078:Positron Emission Tomography Computed Tomography / Q000592:standards*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*
D007457:Iodine Radioisotopes