Reply: 68Ga-DOTATATE PET/CT Versus MRI: Why the Comparison of 68Ga-DOTATATE PET/CT to an Appropriate MRI Protocol Is Essential

摘要

>REPLY: We thank Dr. Gravel and colleagues for their comments on our study, which showed the superiority of 68Ga-DOTATATE PET/CT over other imaging modalities in the evaluation of head and neck paragangliomas (HNPGLs) (id="xref-ref-1-1" class="xref-bibr" href="#ref-1">1). Specifically, they comment that the use of MRI within the study is suboptimal because of the lack of contrast-enhanced angio-MRI (CE-MRA) covering the head and neck area. First, we would like to emphasize that 68Ga-DOTATATE PET/CT is particularly adapted to the exploration of HNPGLs because of the highly elevated uptake values within these tumors, with an excellent and uniquely favorable signal-to-background ratio. This pattern enables easy detection of millimeter-sized tumors, which, unlike in MRI, is less dependent on operator experience. This notion is shared by most practitioners who work in high-volume hospitals in which this modality is available. It is true that the angio-MR sequences are sensitive and that whole-body MRI can be applied to these patients. However, in our paper, we assessed sensitivitya€”not specificitya€”in the detection of HNPGLs. Furthermore, in their letter, the authors cite references supporting the comparable sensitivity of CE-MRA and conventional MRI (id="xref-ref-2-1" class="xref-bibr" href="#ref-2">2). Therefore, their claim that we did not use a state-of-the-art imaging method is not convincing. We would also like to point out that the original Eunice Kennedy Shriver NICHD protocol 00-CH-0093 was approved to perform this study using conventional MRI in the evaluation of HNPGLs in comparison to other imaging modalities, as stated in our paper. Any deviation from this protocol after study commencement several years ago would be scientific error. It is not scientifically sound to add new imaging modalities to an ongoing study when a new imaging modality and its application to a particular cancer appears in the literature (id="xref-ref-2-2" class="xref-bibr" href="#ref-2">2). The same criticism could apply to a study cited by the authors (id="xref-ref-3-1" class="xref-bibr" href="#ref-3">3) in which 111In-pentetreotide (Octreoscan; Mallinckrodt/Covidien) was used despite the fact that 68Ga-DOTATATE PET was already on the horizon and was suggested to be a promising agent for primary and metastatic paragangliomas, including those of the head and neck (id="xref-ref-4-1" class="xref-bibr" href="#ref-4">4,id="xref-ref-5-1" class="xref-bibr" href="#ref-5">5).