• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.

• Journal of Preventive Medicine and Public Health
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• v.54 no.6
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• pp.412-421
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• 2021

Objectives: Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent metabolic disease. Muscle is known to influence NAFLD development. Therefore, this study aimed to determine the relationships among low muscle mass, NAFLD, and hepatic fibrosis using various definitions of low muscle mass and NAFLD diagnostic methods, including magnetic resonance imaging-based proton density fat fraction (MRI-PDFF). Methods: This cross-sectional study included 320 participants (107 males, 213 females) from the Korean Genome and Epidemiology Study on Atherosclerosis Risk of Rural Areas in the Korean General Population cohort. Muscle mass was assessed using whole-body dual-energy X-ray absorptiometry and adjusted for the height squared, body weight, and body mass index (BMI). NAFLD was diagnosed using ultrasonography (US), MRI-PDFF, and the comprehensive NAFLD score (CNS). Hepatic fibrosis was assessed using magnetic resonance elastography. Multivariable logistic and linear regression analyses were performed to determine the aforementioned associations. Results: According to US, 183 participants (57.2%) had NAFLD. Muscle mass adjusted for body weight was associated with NAFLD diagnosed using US (odds ratio [OR], 3.00; 95% confidence interval [CI], 1.70 to 5.31), MRI-PDFF (OR, 2.00; 95% CI, 1.13 to 3.53), and CNS (OR, 3.39; 95% CI, 1.73 to 6.65) and hepatic fibrosis (males: β=-0.070, p<0.01; females: β=-0.037, p<0.04). Muscle mass adjusted for BMI was associated with NAFLD diagnosed by US (OR, 1.71; 95% CI, 1.02 to 2.86) and CNS (OR, 1.95; 95% CI, 1.04 to 3.65), whereas muscle mass adjusted for height was not associated with NAFLD. Conclusions: Low muscle mass was associated with NAFLD and liver fibrosis; therefore, maintaining sufficient muscle mass is important to prevent NAFLD. A prospective study and additional consideration of muscle quality are needed to strengthen the findings regarding this association.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.1
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• pp.72-78
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• 2009

Purpose: Bone mineral density (BMD) measurements need to be precise enough to be capable of detecting small changes in bone mass of rats. Using a regular dual-energy X-ray absorptiometry (DXA), we measured many BMD of various skeletal sites in rats to examine precision of DXA in relation to the repositioning on the bones of rats. Materials and Methods: Using DXA and small animal software, scans were performed 4 times in all 12 male rats without repositioning (Group 1a). Another four scans for 6 of 12 rats were done with repositioning between scans (Group 2). Customized regions of interest (ROIs), encapsulate the right hind limb, L1-4, skull and pelvic bones were drawn at each measurement. The precision of the measurements was evaluated by measuring the coefficient of variation (CV) of four measurements of BMD at each skeletal site of all rats with or without repositioning. Significance of differences between group 1b (six rats out of group 1a, which were come under group 2) and group2 were evaluated with Wilcoxon Signed Rank Sum Test. Results: CVs obtained at different skeletal sites of all measurements in Group 1b and 2. It was $3.51{\pm}1.20$, $ 2.62{\pm}1.20$ for the hindlimb (p=0.173), $3.83{\pm}2.02$, $4.59{\pm}2.02$ for L1-4 (p=0.600), $3.73{\pm}1.87$, $1.53{\pm}0.89$ for skull (p=0.046), and $2.92{\pm}0.60$, $1.45{\pm}0.60$ for pelvic bones (p=0.075). Conclusion: Our study demonstrates that the DXA technique has the precision necessary when used to assess BMD for various skeletal sites in rats regardless of repositioning.