Preoperative assessment of the degree of liver fibrosis is important to determine treatment strategies. In this study, galactosyl human serum albumin single-photon emission-computed tomography and ethoxybenzyl (EOB) contrast-enhanced magnetic resonance imaging (MRI) were used to assess the changes in hepatocyte function after liver fibrosis, and the standardized uptake value (SUV) was combined with gadolinium EOB-diethylenetriaminepentaacetic acid to evaluate its added value for liver fibrosis staging.A total of 484 patients diagnosed with hepatocellular carcinoma who underwent liver resection between January 2010 and August 2018 were included. Resected liver specimens were classified based on pathological findings into nonfibrotic and fibrotic groups (stratified according to the Ludwig scale). Galactosyl human serum albumin-single-photon emission-computed tomography and EOB contrast-enhanced MRI examinations were performed, and the mean SUVs (SUV mean ) and contrast enhancement indices (CEIs) were obtained. The diagnostic value of the acquired SUV and CEIs for fibrosis was assessed by calculating the area under the receiver operating characteristic curve (AUC).In the receiver operating characteristic analysis, SUV + CEI showed the highest AUC in both fibrosis groups. In particular, in the comparison between fibrosis groups, SUV + CEI showed significantly higher AUCs than SUV and CEI alone in discriminating between fibrosis (F3 and 4) and no or mild fibrosis (F0 and 2) (AUC: 0.879, vs SUV [P = 0.008], vs. CEI [P = 0.023]), suggesting that the combination of SUV + CEI has greater diagnostic performance than the individual indices.Combining the SUV and CEI provides high accuracy for grading liver fibrosis, especially in differentiating between grades F0 and 2 and F3-4. SUV and gadolinium EOB-diethylenetriaminepentaacetic acid-enhanced MRI can be noninvasive diagnostic methods to guide the selection of clinical treatment options for patients with liver diseases.Abbreviations: 99m Tc-GSA = Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin, AUC = area under the receiver operating characteristic curve, EOB = ethoxybenzyl, Gd-EOB-DTPA = gadolinium ethoxybenzyldiethylenetriaminepentaacetic acid, GSA = galactosyl human serum albumin, MRI = resonance imaging, ROC = receiver operating characteristic, ROI = region-of interest, SI = signal intensity, SPECT-CT = single-photon emission-computed tomography, SUV = standardized uptake value, US = ultrasound, VOI = volume of interest.

Quantitative analysis using a standardized uptake value (SUV) has become possible for singlephoton emission computed tomography-computed tomography (SPECT-CT) of bone. However, previous research was targeted to the trunk area, and there are few studies for the head and neck region. Therefore, the purpose of this study was to determine the optimal image reconstruction conditions for bone SPECT of the head and neck using a phantom study. Method: The radioactivity concentration of the 99m Tc solution enclosed in the cylindrical phantom was set to the same count rate as in clinical cases, and six hot spheres (10, 13, 17, 22, 28, 37 mm) with four times the concentration were placed within it. The image reconstruction was 3D-OSEM, and the reconstruction conditions were varied by the number of iterative updates and the width of the Gaussian filter. Quantitative evaluations of the image quality were performed using the % contrast, background variability, and SUV for the hot spheres and background. A visual evaluation was performed by four observers to determine the optimal image reconstruction conditions for bone SPECT of the head and neck region. Result: The concentration of the 99m Tc solution enclosed in the phantom was 6.95 (kBq/ml). Based on the results of the quantitative and visual evaluations, the optimal image reconstruction conditions were iterative updates=60 (subset: 10, iteration: 6) and a Gaussian filter of 7.8 mm. Conclusion:The optimal image reconstruction conditions were subset=10, iterations=6, and a Gaussian filter of 7.8 mm.

This study (1) evaluated the perceptual and objective physical quality of digital radiographic chest images processed for different purposes (routine hospital use, lung cancer screening, and pneumoconiosis screening), and (2) quantified objectively the quality of chest images visually graded by the Japan National Federation of Industrial Health Organization (ZENEIREN). Four observers rated the images using a visual grading score (VGS) according to ZENEIREN's quality criteria. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured. Between groups, differences were assessed using ANOVA (followed by Bonferroni multiple comparisons) or unpaired t-test. The Pearson's correlation coefficients were calculated for the correlation between perceptual quality and objective physical image quality.The image quality perceived by the observers and the SNR measurements were highest for the images generated using parameters recommended for lung cancer screening. The images processed for pneumoconiosis screening were rated poorest by the observers and showed the lowest objective physical quality measurements. The chest images rated high quality by ZENEIREN generally showed a higher objective physical image quality. The SNR correlated well with VGS, but CNR did not. Highly significant differences between the processing parameters indicate that image processing strongly influences the perceptual quality of digital radiographic chest images.

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