18F-FDG PET/CT for the pre-surgical localization of epileptogenic focus among paediatric patients with drug resistant epilepsy in Malaysia: perspective of a nuclear medicine physician.

BACKGROUND: Scalp video electroencephalography monitoring (VEM) and brain MRI sometime fail to identify the epileptogenic focus (EF) in patients with drug resistant epilepsy (DRE). 18F-FDG PET/CT has been shown to improve the detection of EF in patients but is not widely used in Malaysia. Thus, the objective of this study was to identify whether 18F-FDG PET/CT conferred an added benefit in the pre-surgical evaluation of DRE. METHODS: Retrospective review of 119 consecutive paediatric patients referred for 18F-FDG-PET/CT at the Department of Nuclear Medicine of the National Cancer Institute, Putrajaya. All had DRE and underwent evaluation at the Paediatric Institute, Hospital Kuala Lumpur. Visually detected areas of 18F-FDG-PET/CT hypometabolism were correlated with clinical, MRI and VEM findings. RESULTS: Hypometabolism was detected in 102/119 (86%) 18FFDG- PET/CT scans. The pattern of hypometabolism in 73 patients with normal MRI was focal unilobar in 16/73 (22%), multilobar unilateral in 8/73 (11%), bilateral in 27/73 (37%) and global in 5/73 (7%) of patients; whilst 17/73 (23%) showed normal metabolism. In 46 patients with lesions on MRI, 18F-FDG-PET/CT showed concordant localisation and lateralization of the EF in 30/46 (65%) patients, and bilateral or widespread hypometabolism in the rest. Addition of 18FFDG PET/CT impacted decision making in 66/119 (55%) of patients; 24/73 with non-lesional and 30/46 patients with lesional epilepsies were recommended for surgery or further surgical work up, whilst surgery was not recommended in 11/46 patients with lesional epilepsy due to bilateral or widespread hypometabolism. 25 patients subsequently underwent epilepsy surgery, with 16/25 becoming seizure free following surgery. CONCLUSION: 18F-FDG-PET/CT has an added benefit for the localization and lateralization of EF, particularly in patients with normal or inconclusive MRI.

Clinicopathological features and treatment outcome of paediatric differentiated thyroid cancer treated with Radioactive Iodine-131 therapy in Hospital Kuala Lumpur, Malaysia.

BACKGROUND: Radioactive iodine 131I (RAI) therapy is one of the definitive treatments for paediatric differentiated thyroid cancer (DTC) initiated at nuclear medicine departments. In Malaysia, there is a need to identify the standardisation of treatment regimes to align with international standards. We aimed to evaluate the clinicopathological features and the patient response to RAI therapy among paediatric DTC cases at Hospital Kuala Lumpur (HKL), Malaysia. METHODS: A retrospective, longitudinal study was conducted among paediatric DTC patients treated with RAI in HKL and followed up between 2000-2016. Sixty-five patients were studied (mean period: 58.8±36 months). The clinicopathological data of the patients was recorded, and descriptive analysis was made. The association between categorical and continuous data with disease status was assessed using chi-square and Kruskal-Wallis tests, p-value <0.05 taken as statistically significant. RESULTS: Most patients were female (78.5%), and adolescents comprised 89.2%. Pre-pubertal age, those presenting with cervical nodal involvement, extra-thyroidal extension and lymphovascular invasion were significantly associated with distant metastases at presentation. There was no mortality reported during the follow-up period. Sixty per cent of patients achieved remission, while 40% had persistent disease. The persistent disease was significantly correlated with distant metastasis at presentation (p=0.025). CONCLUSIONS: Paediatric DTC manifests with a more extensive disease burden at presentation and requires multiple RAI doses. Despite this, it carries an excellent overall prognosis.