OBJECTIVE: To extend the application of Gibbs artifact reduction method that exploits local subvoxel- shifts (LSS) to zero- padded k-space magnetic resonance imaging (MRI) data. METHODS: We investigated two approaches to extending the application of LSS-based method to under-sampled data. The first approach, namely LSS+ interpolation, utilized the original LSS-based method to minimize the local variation on nonzero-padding reconstructed images, followed by image interpolation to obtain the final images. The second approach, interlaced local variation, used zero-padded Fourier transformation followed by elimination of Gibbs artifacts by minimizing a novel interlaced local variations (iLV) term. We compared the two methods with the original LSS and Hamming window filter algorithms, and verified their feasibility and robustness in phantom and data. RESULTS: The two methods proposed showed better performance than the original LSS and Hamming window filters and effectively eliminated Gibbs artifacts while preserving the image details. Compared to LSS + interpolation method, iLV method better preserved the details of the images. CONCLUSIONS The iLV and LSS+interpolation methods proposed herein both extend the application of the original LSS method and can eliminate Gibbs artifacts in zero-filled k-space data reconstruction images, and iLV method shows a more prominent advantage in retaining the image details.
Algorithms ; Artifacts ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Phantoms, Imaging

Objective:To investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] and arterial stiffness in the physical examination population.Methods:It was a cross-sectional study, the data were collected from adults who received physical examination in the Health Management Center of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2016 to April 2022, all the participants completed the tested for brachial and ankle pulse wave conduction velocity (baPWV) and serum 25(OH)D. The general information, anthropometric metrics and relevant laboratory data were recorded. A total of 41 090 participants were included. According to baPWV, the subjects were divided into arterial stiffness group (baPWV≥1 800 cm/s, n=2 440) and normal group (baPWV<1 800 cm/s, n=38 650). The subjects were categorized into three groups based on serum 25(OH)D level: sufficient group [25(OH)D≥30 μg/L, n=2 830], insufficient group [25(OH)D 20-<30 μg/L, n=11 400] and deficiency group [25(OH)D<20 μg/L, n=26 860]. Logistic regression analysis was performed to assess the relationship between 25(OH)D and arterial stiffness. The dose-response relationship between serum 25(OH)D levels and the risk of arterial stiffness was analyzed using restricted cubic spline functions. Results:Of the 41 090 participants included, 25 001 were males and 16 089 were females, 2 440 cases (5.94%) were detected with arterial stiffness. Compared with normal group, the age, body mass index, uric acid, creatinine, 25(OH)D level and proportion of dyslipidemia were all significantly higher in the arterial stiffness group [(60.1±9.8) vs (46.0±10.4) years, (25.3±3.4) vs (24.5±3.4) kg/m 2, (356.2±99.6) vs (345.0±95.8) μmol/L, (77.0±21.5) vs (73.8±15.9) μmol/L, (18.51±7.93) vs (18.11±7.27) μg/L, 48.4% vs 38.5%], while the glomerular filtration rate was significantly lower [(87.2±16.1) vs (99.1±14.0) ml·min -1·1.73 m -2] (all P<0.05). The 25(OH)D deficiency was positively correlated with the risk of arteriosclerosis ( OR=1.26, 95% CI: 1.07-1.51), and the risk of arterial stiffness increased by 16% for every 10 μg/L decrease in serum 25(OH)D levels (all Ptrend<0.001). The mean baPWV level in the 25(OH)D deficiency group was 12.45 cm/s (95% CI: 3.89-21.02) higher than that in 25(OH)D adequacy group; and for every 10 μg/L decrease in 25(OH)D, the baPWV increased by 11.23 cm/s (95% CI: 8.11-14.19) (all Ptrend<0.001). The association between serum 25(OH)D deficiency and the risk of arteriosclerosis was more pronounced in individuals with a body mass index of 24 kg/m2 or above ( Pfor interaction=0.039). Moreover, there was an “L”-shaped dose-response relationship between serum 25(OH)D level and the risk of arteriosclerosis ( Pnon-linear<0.001). Conclusion:The 25(OH)D deficiency is closely correlated with the risk of arteriosclerosis in the physical examination population, and the association is stronger in overweight individuals.