Accuracy of [¹⁸F]fluorodopa positron emission tomography for diagnosing and localizing focal congenital hyperinsulinism

Objectives: Focal lesions in infants with congenital hyperinsulinism (HI) represent areas of adenomatosis that express a paternally derived ATP-sensitive potassium channel mutation due to embryonic loss of heterozygosity for the maternal 11p region. This study evaluated the accuracy of ¹⁸F-fluoro- L-dihydroxyphenylalanine ([¹⁸F]DOPA) positron emission tomography (PET) scans in diagnosing focal vs. diffuse disease and identifying the location of focal lesions. Design: A total of 50 infants with HI unresponsive to medical therapy were studied. Patients were injected iv with [¹⁸F]DOPA, and PET scans were obtained for 50-60 min. Images were coregistered with abdominal computed tomography scans. PET scan interpretations were compared with histological diagnoses. Results: The diagnosis of focal or diffuse HI was correct in 44 of the 50 cases (88%). [¹⁸F]DOPA PET identified focal areas of high uptake of radiopharmaceutical in 18 of 24 patients with focal disease. The locations of these lesions matched the areas of increased [ ¹⁸F]DOPA uptake on the PET scans in all of the cases. PET scan correctly located five lesions that could not be visualized at surgery. The positive predictive value of [¹⁸F]DOPA in diagnosing focal adenomatosis was 100%, and the negative predictive value was 81%. Conclusions: [¹⁸F]DOPA PET scans correctly diagnosed 75% of focal cases and were 100% accurate in identifying the location of the lesion. These results suggest that [¹⁸F]DOPA PET imaging provides a useful guide to surgical resection of focal adenomatosis and should be considered as a guide to surgery in all infants with congenital HI who have medically uncontrollable disease.