Objectives This study sought to provide data supporting the expanded clinical use of respiratory gating by assessing the diagnostic accuracy of breathing motion correction using amplitude-based respiratory gating. Methods A respiratory movement tracking device was attached to a PET-computed tomography scanner, and images were obtained in respiratory gating mode using a motion phantom that was capable of sensing vertical motion. Specifically, after setting amplitude changes and intervals according to the movement cycle using a total of nine combinations of three waveforms and three amplitude ranges, respiratory motion-corrected images were reconstructed using the filtered back projection method. After defining areas of interest in the acquired images in the same image planes, statistical analyses were performed to compare differences in standardized uptake value (SUV), lesion volume, full width at half maximum (FWHM), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Results SUVmax increased by 89.9%, and lesion volume decreased by 27.9%. Full width at half maximum decreased by 53.9%, signal-to-noise ratio increased by 11% and contrast-to-noise ratio increased by 16.3%. Optimal results were obtained when using a rest waveform and 35% duty cycle, in which the change in amplitude in the respiratory phase signal was low, and a constant level of long breaths was maintained. Conclusions These results demonstrate that respiratory-gated PET-CT imaging can be used to accurately correct for SUV changes and image distortion caused by respiratory motion, thereby providing excellent imaging information and quality.

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In this study, a susceptibility weighted image (SWI) showed a wrapped phase and a non-uniformity of the rapid susceptibility difference. Consequently, the bandwidth limits at low frequency were improved by applying HPF. From November 2013 to March 2014, a three-dimensional SWI was obtained from patients and compared with the existing images and HPF phase images. The maximum and minimum signal intensity differences and non-uniformity were analyzed. As a result, a high pass filter before and after applying the maximum and minimum of the signal intensity difference was decreased by 274.16% (498.98), and the non-uniformity was decreased by 439.55% (19.83). After applying the HPF, a comparison with the existing phase images revealed the HPF phase images to have high signal and image uniformity of the SWI image. A high pass filter method can effectively remove the non-uniformity and improve the overall image quality.

The indiscriminate use of phthalate-containing products in daily life can adversely affect pregnant women and their children. Phthalate can modify DNA methylation in the cord blood of infants. Therefore, we examined the association between prenatal phthalate exposure and cord blood DNA methylation in a Korean birth cohort. Phthalate levels in maternal blood during late pregnancy and cord blood were measured and DNA methylation of cord blood was measured using the Illumina HumanMethylationEPIC BeadChip kit. The association between CpG methylation and phthalate levels was analyzed using the ‘limma’ package in R, adjusting for infant sex, maternal body mass index, current maternal smoking status, and estimated leukocyte composition. We used data from 274 samples for estimating mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-(2-ethyl-5-hydroxyhxyl) phthalate (MEHHP) levels and 273 samples for estimating mono-n-butyl phthalate (MnBP) levels to determine maternal phthalate concentrations during late pregnancy. Additionally, 102 samples were analyzed for all three types of phthalates in the cord blood. The meta-analysis revealed significant associations between the CpG sites near the CHN2 and CUL3 genes and cord blood MEOHP and MnBP concentrations, respectively. However, the three maternal phthalate concentrations during late pregnancy showed no significant association with CpG sites. In conclusion, prenatal phthalate exposure is significantly associated with DNA methylation at several CpG sites.