18F-DOPA positron emission tomography for the detection of glomus tumours

The purpose of this study was to evaluate F-18-DOPA whole-body positron emission tomography (F-18-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. F-18-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D (SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. F-18-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by F-18-DOPA PET. Under blinded conditions, F-18-DOPA PET and MRI revealed full agreement in seven patients. partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by F-18-DOPA PET were confirmed by MRI. The correlation of F-18-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on F-18-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. F-18-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.