Quantification of the Elastic Property of Normal Thigh Muscles Using MR Elastography:Our Initial Experience

Purpose@#This study aimed to apply MR elastography (MRE) to achieve in vivo evaluation of the elastic properties of thigh muscles and validate the feasibility of quantifying the elasticity of normal thigh muscles using MRE. @*Materials and Methods@#This prospective study included 10 volunteer subjects [mean age, 32.5 years, (range, 23–45 years)] who reported normal activities of daily living and underwent both T2-weighted axial images and MRE of thigh muscles on the same day. A sequence with a motion-encoding gradient was used in the MRE to map the propagating shear waves in the muscle. Elastic properties were quantified as the shear modulus of the following four thigh muscles at rest; the vastus medialis, vastus lateralis, adductor magnus, and biceps femoris. @*Results@#The mean shear modulus was 0.98 ± 0.32 kPa and 1.00 ± 0.33 kPa for the vastus medialis, 1.10 ± 0.46 kPa and 1.07 ± 0.43 kPa for the vastus lateralis, 0.91 ± 0.41 kPa and 0.93 ± 0.47 kPa for the adductor magnus, and 0.99 ± 0.37 kPa and 0.94 ± 0.32 kPa for the biceps femoris, with reader 1 and 2, respectively. No significant difference was observed in the shear modulus based on sex (p < 0.05). Aging consistently showed a statistically significant negative correlation (p < 0.05) with the shear modulus of the thigh muscles, except for the vastus medialis (p = 0.194 for reader 1 and p = 0.355 for reader 2). @*Conclusion@#MRE is a quantitative technique used to measure the elastic properties of individual muscles with excellent inter-observer agreement. Age was consistently significantly negatively correlated with the shear stiffness of muscles, except for the vastus medialis.

Usefulness of CT-Guided Percutaneous TransthoracicNeedle Lung Biopsies in Patients with SuspectedPulmonary Infection

Objective@#This study aimed to evaluate the clinical benefits and risks of CT-guided percutaneous transthoracic needle lung biopsies (PTNBs) in patients with a suspected pulmonary infection. @*Materials and Methods@#This study included 351 CT-guided PTNBs performed in 342 patients (mean age, 58.9 years [range,17–91 years]) with suspected pulmonary infection from January 2010 to December 2016. The proportion of biopsies that revealed the causative organism for pulmonary infection and that influenced patient’s treatment were measured. Multivariateanalyses were performed to identify factors associated with PTNB that revealed the causative organism or affected the treatment. Finally, the complication rate was measured. @*Results@#CT-guided PTNB revealed the causative organism in 32.5% of biopsies (114/351). The presence of necrotic components in the lesion (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1–2.7; p = 0.028), suspected pulmonary tuberculosis (OR, 2.0; 95% CI, 1.2–3.5; p = 0.010), and fine needle aspiration (OR, 2.5; 95% CI, 1.1–5.8; p = 0.037) were factors associated with biopsies that revealed the causative organism. PTNB influenced patient’s treatment in 40.7% (143/351) of biopsies. The absence of leukocytosis (OR, 1.9; 95% CI, 1.0–3.7; p = 0.049), presence of a necrotic component in the lesion (OR, 2.4; 95% CI, 1.5–3.8; p < 0.001), and suspected tuberculosis (OR, 1.7; 95% CI, 1.0–2.8; p = 0.040) were factors associated with biopsies that influenced the treatment. The overall complication rate of PTNB was 19% (65/351). @*Conclusion@#In patients with suspected pulmonary infection, approximately 30–40% of CT-guided PTNBs revealed the causative organism or affected the treatment. The complication rate of PTNB for suspected pulmonary infection was relatively low.

Diameter of the Solid Component in Subsolid Nodules on Low-Dose Unenhanced Chest Computed Tomography: Measurement Accuracy for the Prediction of Invasive Component in Lung Adenocarcinoma

OBJECTIVE: To determine if measurement of the diameter of the solid component in subsolid nodules (SSNs) on low-dose unenhanced chest computed tomography (CT) is as accurate as on standard-dose enhanced CT in prediction of pathological size of invasive component of lung adenocarcinoma. MATERIALS AND METHODS: From February 2012 to October 2015, 114 SSNs were identified in 105 patients that underwent low-dose unenhanced and standard-dose enhanced CT pre-operatively. Three radiologists independently measured the largest diameter of the solid component. Intraclass correlation coefficients (ICCs) were used to assess inter-reader agreement. We estimated measurement differences between the size of solid component and that of invasive component. We measured diagnostic accuracy of the prediction of invasive adenocarcinoma using a size criterion of a solid component ≥ 6 mm, and compared them using a generalized linear mixed model. RESULTS: Inter-reader agreement was excellent (ICC, 0.84.0.89). The mean ± standard deviation of absolute measurement differences between the solid component and invasive component was 4 ± 4 mm in low-dose unenhanced CT and 5 ± 4 mm in standard-dose enhanced CT. Diagnostic accuracy was 81.3% (95% confidence interval, 76.7.85.3%) in low-dose unenhanced CT and 76.6% (71.8.81.0%) in standard-dose enhanced CT, with no statistically significant difference (p = 0.130). CONCLUSION: Measurement of the diameter of the solid component of SSNs on low-dose unenhanced chest CT was as accurate as on standard-dose enhanced CT for predicting the invasive component. Thus, low-dose unenhanced CT may be used safely in the evaluation of patients with SSNs.

Radiation Dose Calculation in the Surrounding Organs during Brachytherapy of Prostate Cancer / 의학물리

As a part of estimating quantitative radiation treatment doses, we produced a mathematical phantom based on the standard Korean male. Then, with the prostate as the source organ, we calculated the absorbed dose in the prostate and surrounding organs forecasted to occur during brachytherapy for prostate cancer. To simulate the procedure, we selected (25)I and (103)Pd useful in brachytherapy of the prostate as the radionucleids and made an assumption that 1 Ci of initial radioactivity is administered. As a result, we found that the prostate, as the source organ, indicated 101 Gy/Ci and 7.24 Gy/Ci, respectively, in case of (125)I and (103)Pd. With the exception of the prostate, organs with high absorbed doses were found to be in the order of the penis and scrotum, sigmoid colon, testicles and the urinary bladder, which are relatively close to the prostate.

Assessment of Absorbed Dose of by Organ according to Thyroidal Uptake of Radioactive Iodine for Adult Korean Males / 의학물리

In an effort to assess the internal absorbed dose of radionuclides that is suitable to Koreans' physiological characteristics, we asked 28 male Koreans to take 131I orally, determined the thyroidal uptake and daily urination ratio, and assessed the absorbed dose by organ. As a result, first, 24 hours after administering, the average thyroidal uptake and the daily urination ratio registered 19.70% and 71.12%, respectively. Second, the whole body effective dose according to the thyroidal uptake calculated herein and the existing ICRP-suggested thyroidal uptake of 30% offered 1.464E-08 Sv and 2.189E-08 Sv, respectively, showing a 1.5 times difference. To evaluate the quantity of the absorbed dose of radioactive iodine, we can better reduce the error in assessing the body exposure dose by conducting measurement according to human races rather than depending on the existing ICRP data.

Oriental Medicine Needs Information Technology; Survey on Needs from Domain Experts and Medical Consumer / 대한의료정보학회지

OBJECTIVE: The objective of this research is to survey the requirements of Oriental Medical Informatics, and to suggest a direction that Oriental Medical Informatics development may take. METHODS: Consumers and medical experts were randomly selected, and 14 uestions for consumers and 17 questions for medical experts were sent to respondents by mail and e-mail. RESULTS: Both consumers and medical experts were greatly concerned with the systemized dissemination of Oriental Medical Information, but they were not satisfied with it because of the perceived low quality of the information. Medical experts responded that they need standards and statistical evidences for Oriental Medicine. Consumers demanded good-quality information about diseases and health management. CONCLUSION: To carry out Oriental Medical Informatics, it is necessary to conduct a joint research between the sectors of Oriental Medicine and Information Technology, followed by the development of a standard information infrastructure. Oriental Medicine must also have standards in terms of medical data content, data format, and data communication, to ensure the reliability of the disseminated information on Oriental Medicine.