Respiration-averaged CT for attenuation correction in non-small-cell lung cancer.
OBJECTIVE
Breathing causes artefacts on PET/CT images. Cine CT has been used to reduce respiratory artefacts by acquiring multiple images during a single breathing cycle. The aim of this prospective study in non-small-cell lung cancer (NSCLC) patients was twofold. Firstly, we sought to compare the motion artefacts in PET/CT images attenuation-corrected with helical CT (HCT) and with averaged CT (ACT), which provides an average of cine CT images. Secondly, we wanted to evaluate the differences in maximum standardized uptake values (SUV(max)) between HCT and ACT.


METHODS
Enrolled in the study were 80 patients with NSCLC. PET images attenuation-corrected with HCT (PET/HCT) and with ACT (PET/ACT) were obtained in all patients. Misregistration was evaluated by measurement of the curved photopenic area in the lower thorax of the PET images for all patients and direct measurement of misregistration for selected lesions. SUV(max) was measured separately at the primary tumours, regional lymph nodes, and background.


RESULTS
A total of 80 patients with NSCLC were included. Significantly lower misregistrations were observed in PET/ACT images than in PET/HCT images (below-thoracic misregistration 0.25+/-0.58 cm vs. 1.17+/-1.17 cm, p<0.001; lesion misregistration 1.38+/-2.10 vs. 3.10+/-4.09, p=0.013). Significantly higher SUV(max) were noted in PET/ACT images than in PET/HCT images in the primary tumour (p<0.001) and regional lymph nodes (p<0.001). Compared with PET/HCT images, the magnitude of SUV(max) in PET/ACT images was higher by 0.35 for the main tumours and 0.34 for lymph nodes.


CONCLUSIONS
Due to its significantly reduced misregistration, PET/ACT provided more reliable SUV(max) and may be useful in treatment planning and monitoring the therapeutic response in patients with NSCLC.
Cheng
Nai-Ming
NM
Department of Nuclear Medicine, Chang Gung Memorial Hospital Linkou Medical Center, Taoyuan, Taiwan.
Yu
Chih-Teng
CT
Ho
Kung-Chu
KC
Wu
Yi-Cheng
YC
Liu
Yuan-Chang
YC
Wang
Chih-Wei
CW
Yen
Tzu-Chen
TC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D015203:Reproducibility of Results; D012119:Respiration; D014057:Tomography, X-Ray Computed / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18