Background: Large-scale data on the diagnostic performance of functional imaging in metastatic pheochromocytoma/paraganglioma (PPGL) are scarce. Objective: To analyze the diagnostic accuracy of functional imaging for the assessment of metastases during long-term follow-up (FU). Design: Retrospective cohort study, 1991–2025. Setting: Referral center. Outcomes: Sensitivity and specificity of ¹²³MIBG-, ¹⁸F-DOPA-, ⁶⁸GaDOTA-based and ¹⁸FDG PET/CT. Patients: Patients with metastatic PPGL and without PPGL, ≥1 functional imaging prior to first diagnosis and/or during FU and FU ≥ 3 months. Results: 59 ¹²³MIBG-, 101 ¹⁸F-DOPA-, 11 ¹⁸FDG- and 74 ⁶⁸GaDOTA-based PET/CT were performed in 57 patients with metastatic PPGL and 37 ¹²³MIBG-, 323 ¹⁸F-DOPA-, 259 ¹⁸FDG- and 641 ⁶⁸GaDOTA-based imaging in 527 patients without PPGL. FU was 11.6 ± 11.4 and 5.1 ± 4.7 years, respectively. Sensitivity for the detection of all metastases (total cohort) by patient-based analysis was comparable between ¹⁸F-DOPA (77%), both ⁶⁸GaDOTA-based tracers combined (67%) and ¹²³MIBG (72%); lesion-based analysis was better for ¹⁸F-DOPA (94%) than for ⁶⁸GaDOTA (85%) and ¹²³MIBG (67%). Specificity (patient- and lesion-based) of ¹⁸F-DOPA vs. ⁶⁸GaDOTA (96–99%) was comparable and better than ¹²³MIBG (73%) and ¹⁸FDG (75%). Conclusions: Sensitivity of ¹⁸F-DOPA was superior to ⁶⁸GaDOTA for the detection of all and bone metastases in the total cohort and in patients with PCC, that of ⁶⁸GaDOTA was better for bone metastases with PGL, specificity was comparable and for both was better than for ¹⁸FDG and ¹²³MIBG. Given the beneficial pharmaceutical properties and favorable diagnostic performance, ¹⁸F-DOPA may be a good alternative to ⁶⁸GaDOTA-based tracers for the functional imaging of metastatic PPGL.

Complex cortical malformations (CCMs), such as hemimegalencephaly and polymicrogyria, are associated with drug-resistant epilepsy and developmental impairment. They share certain neuropathological characteristics including mammalian target of rapamycin (mTOR) activation and an atypical number of white matter neurons. To get a better understanding of the pathobiology of the lesion architecture, we investigated the role of neurite outgrowth inhibitor A (NogoA), a known regulator of neuronal migration. Epilepsy surgery specimens from 16 CCM patients were analyzed and compared with sections of focal cortical dysplasia IIB (FCD IIB, n = 22), tuberous sclerosis complex (TSC, n = 8) as well as healthy controls (n = 15). Immunohistochemistry was used to characterize NogoA, myelination, and mTOR signaling. Digital slides were evaluated automatically with ImageJ. NogoA staining showed a significantly higher expression within the white matter of CCM and FCD IIB, whereas cortical tubers presented levels similar to controls. Further analysis of possible associations of NogoA with other factors revealed a positive correlation with mTOR and seizure frequency. To identify the main expressing NogoA cell type, double staining revealed dysmorphic neuronal white matter cells. Increased NogoA expression is associated with profound inhibition of neuritic sprouting and therefore contributes to a decrease in neuronal network complexity in CCM patients.