Impact d’une méthode originale de synchronisation respiratoire sur la détection des lésions hépatiques en TEP/TDM au F-FDG

In ¹⁸F-Fluoro-Desoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT), respiratory motion induces bias in image interpretations. These movements can introduce organs misregistration between both modalities yielding erroneous attenuation correction and thus wrong maximum standardized uptake values (SUV_max). We present here the results of a clinical study which aims to assess the benefits of a novel respiratory gating method (CT-based) for liver lesions detection. Forty-nine patients planed to undergo hepatic surgery were addressed to our department for PET/CT examination before surgery. Each patient had both standard and CT-based protocols. Hepatic lesions described by two observers on PET images were compared with pathological analysis and intra-operative ultrasound. Sensitivities calculated for observer 1 were 60 and 64% for standard and CT-based, respectively. For the second observer, sensitivities were 58.7 and 72%. CT-based showed a significant increase (P < 0.01) of sensitivity on a per-lesion basis for one observer. CT-based did not improve inter-observer variability. At last, SUV_max were significantly higher with CT-based method (P < 0.001). Respiratory gating CT-based method is easily bearable by the patients. This procedure ensures good matching between both modalities and reduces motion-blurring effect in PET data. CT-based method improves liver lesions detectability and allows more accurate quantitation compared to non-gated FDG-PET/CT examinations.