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PURPOSE: To investigate whether using a Bayesian penalised likelihood reconstruction (BPL) improves signal-to-background (SBR), signal-to-noise (SNR) and SUVmax when evaluating mediastinal nodal disease in non-small cell lung cancer (NSCLC) compared to ordered subset expectation maximum (OSEM) reconstruction. MATERIALS AND METHODS: 18F-FDG PET/CT scans for NSCLC staging in 47 patients (112 nodal stations with histopathological confirmation) were reconstructed using BPL and compared to OSEM. Node and multiple background SUV parameters were analysed semi-quantitatively and visually. RESULTS: Comparing BPL to OSEM, there were significant increases in SUVmax (mean 3.2-4.0, p<0.0001), SBR (mean 2.2-2.6, p<0.0001) and SNR (mean 27.7-40.9, p<0.0001). Mean background SNR on OSEM was 10.4 (range 7.6-14.0), increasing to 12.4 (range 8.2-16.7, p<0.0001). Changes in background SUVs were minimal (largest mean difference 0.17 for liver SUVmean, p<0.001). There was no significant difference between either algorithm on receiver operating characteristic analysis (p=0.26), although on visual analysis, there was an increase in sensitivity and small decrease in specificity and accuracy on BPL. CONCLUSION: BPL increases SBR, SNR and SUVmax of mediastinal nodes in NSCLC compared to OSEM, but did not improve the accuracy for determining nodal involvement. KEY POINTS: • Penalised likelihood PET reconstruction was applied for assessing mediastinal nodes in NSCLC. • The new reconstruction generated significant increases in signal-to-background, signal-to-noise and SUVmax. • This led to an improvement in visual sensitivity using the new algorithm. • Higher SUV max thresholds may be appropriate for semi-quantitative analyses with penalised likelihood.

Original publication




Journal article


Eur Radiol

Publication Date





4098 - 4106


Bayesian, Lung cancer staging, Mediastinal nodes, PET reconstruction, PET-CT, Signal-to-noise, Adult, Aged, Aged, 80 and over, Algorithms, Carcinoma, Non-Small-Cell Lung, Epidemiologic Methods, Female, Fluorodeoxyglucose F18, Humans, Lung Neoplasms, Lymph Nodes, Lymphatic Metastasis, Male, Middle Aged, Multimodal Imaging, Neoplasm Staging, Positron Emission Tomography Computed Tomography, Radiopharmaceuticals