Margined Horn-Shaped Air Chamber for Body-Conduction Microphone.

The sound amplification ratios of sealed air chambers with different shapes were quantitatively compared to design a body-conduction microphone to measure animal scratching sounds. Recently, quantitative monitoring of scratching intensity in dogs has been required. We have already developed a collar with a body-conduction microphone to measure body-conducted scratching sounds. However, the air chamber, one of the components of the body-conduction microphone, has not been appropriately designed. This study compared the amplification ratios of air chambers with different shapes through numerical analysis and experiments. According to the results, the horn-shaped air chamber achieved the highest amplification performance, at least for sound frequencies below 3 kHz. The simulated amplification ratio of the horn-shaped air chamber with a 1 mm height and a 15 mm diameter was 52.5 dB. The deformation of the bottom of the air chamber affected the amplification ratio. Adjusting the margin of the margined horn shape could maintain its amplification ratio at any pressing force. The simulated and experimental amplification ratios of the margined horn-shaped air chamber were 53.4 dB and 19.4 dB, respectively.

Impact of frailty on long-term mortality in older patients receiving intensive care via the emergency department.

The aim of this study was to evaluate whether frailty was associated with 6-month mortality in older adults who were admitted to the intensive care unit (ICU) with an illness requiring emergency care. The investigation was a prospective, multi-center, observational study conducted among the ICUs of 17 participating hospitals. Patients ≥ 65 years of age who were admitted to the ICU directly from an emergency department visit were assessed to determine their baseline Clinical Frailty Scale (CFS) scores before the illness and were surveyed 6 months after admission. Among 650 patients included in the study, the median age was 79 years old, and overall mortality at 6 months was as low as 21%, ranging from 6.2% in patients with CFS 1 to 42.9% in patients with CFS ≥ 7. When adjusted for potential confounders, CFS score was an independent prognostic factor for mortality (one-point increase in CFS, adjusted risk ratio with 95% confidence interval 1.19 [1.09-1.30]). Quality of life 6 months after admission worsened as baseline CFS score increased. However, there was no association between total hospitalization cost and baseline CFS. CFS is an important predictor of long-term outcomes among critically ill older patients requiring emergent admission.

Study of Orally Disintegrating Tablets Using Erythritol as an Excipient Produced by Moisture-Activated Dry Granulation (MADG).

Moisture-activated dry granulation (MADG) is an eco-friendly granulation method that uses a small amount of water and insoluble excipients to absorb moisture. MADG is expected to improve productivity and reduce costs. Erythritol, an excipient used for preparing orally disintegrating tablets (ODTs), has poor tabletability and is difficult to form into tablets by conventional methods, such as high-shear granulation (HSG) and direct compression. In this study, we optimized the manufacturing conditions for ODTs to improve the tabletability of erythritol using MADG. The disintegration time of tablets made using the MADG method was approximately one-tenth that of those made using the HSG method, and the hardness was approximately 1.4 times higher. Moreover, MADG could delay disintegration and improve tabletability. We further attempted to optimize the manufacturing conditions using MADG, particularly in terms of the amount of water used. The disintegration time increased as the amount of added water increased. Moreover, water absorption tests revealed that capillary wetting decreased as the amount of water added increased, but the initial wetting did not change. These results suggested that the disintegration time was prolonged because of the increase in granule density and decrease in capillary wetting with the increase in the amount of added water. The hardness of the tablets increased because of the easy deformation of the granules after the addition of up to 3% water; however, when more than 3% water was added, the hardness decreased because of the aggregation of the granules with the excess water. Finally, two-dimensional maps of the effect of the amount of added water and water activity indicated that tablets with a hardness of ≥80 N and a disintegration time of ≤15 s could be produced by adjusting the amount of added water to within the range of 2.2-3.3% and water activity to 0.3-0.53. These results indicate that MADG can improve the tabletability of erythritol and be used for the granulation of ODTs. Tablets with appropriate hardness and disintegration properties can be produced by adjusting the water content to approximately 2.7% and the water activity to approximately 0.4 when producing ODTs with MADG.

[Quantitative Evaluation of Airway Lesions in Chronic Obstructive Pulmonary Disease by Applying Deep Learning Reconstruction to Ultra-high-resolution CT Images: Correlation between Wall Area Percentage and Forced Expiratory Volume in One Second Percentage].

PURPOSE: Using ultra-high-resolution images reconstructed with the Advanced intelligent Clear-IQ Engine (AiCE) lung to measure wall area percentage (WA%), we demonstrated that WA% measured in more distal bronchus has a stronger correlation with respiratory function (FEV1%). Furthermore, we also demonstrated that WA% measured from images with the higher spatial resolution has a stronger correlation with FEV1%. METHODS: The modulation transfer function (MTF) and noise power spectrum (NPS) of the ultra-high-resolution images reconstructed by the AiCE body and the AiCE lung were compared. In addition, WA% from the first- to seventh-generation bronchus was measured for B1 and B10 in the right lung from clinical images obtained with the two reconstruction methods, and the correlation coefficients with FEV1% were evaluated. RESULTS: The MTF was more superior for the AiCE lung than for the AiCE body, and the NPS was lower for the AiCE lung than for the AiCE body in the low-frequency region. The correlation between WA% and FEV1% was slightly stronger in the AiCE lung than in the AiCE body. CONCLUSION: This study showed that WA% measured from the 7th-generation bronchus using ultra-high-resolution images reconstructed with the AiCE lung strengthens the correlation with FEV1%. Furthermore, the higher the spatial resolution of the measurement images, the stronger the correlation between WA% and FEV1%.

[A Review of Current Knowledge for X-ray Energy in CT: Practical Guide for CT Technologist].

In computed tomography (CT) systems, the optimal X-ray energy in imaging depends on the material composition and the subject size. Among the parameters related to the X-ray energy, we can arbitrarily change only the tube voltage. For years, the tube voltage has often been set at 120 kVp. However, since about 2000, there has been an increasing interest in reducing radiation dose, and it has led to the publication of various reports on low tube voltage. Furthermore, with the spread of dual-energy CT, virtual monochromatic X-ray images are widely used since the contrast can be adjusted by selecting the optional energy. Therefore, because of the renewed interest in X-ray energy in CT imaging, the issue of energy and imaging needs to be summarized. In this article, we describe the basics of physical characteristics of X-ray attenuation with materials and its influence on the process of CT imaging. Moreover, the relationship between X-ray energy and CT imaging is discussed for clinical applications.

Quantitative measurements of emphysema in ultra-high resolution computed tomography using model-based iterative reconstruction in comparison to that using hybrid iterative reconstruction.

The percentage of low attenuation volume ratio (LAVR), which is measured using computed tomography (CT), is an index of the severity of emphysema. For LAVR evaluation, ultra-high-resolution (U-HR) CT images are useful. To improve the image quality of U-HRCT, iterative reconstruction is used. There are two types of iterative reconstruction: hybrid iterative reconstruction (HIR) and model-based iterative reconstruction (MBIR). In this study, we physically and clinically evaluated U-HR images reconstructed with HIR and MBIR, and demonstrated the usefulness of U-HR images with MBIR for quantitative measurements of emphysema. Both images were reconstructed with a slice thickness of 0.25 mm and an image matrix size of 1024 × 1024 pixels. For physical evaluation, the modulation transfer function (MTF) and noise power spectrum (NPS) of HIR and MBIR were compared. For clinical evaluation, LAVR calculated from HIR and MBIR were compared using the Wilcoxon matched-pairs signed-rank test. In addition, the correlation between LAVR and forced expiratory volume in one second (FEV1%) was evaluated using the Spearman rank correlation test. The MTFs of HIR and MBIR were comparable. The NPS of MBIR was lower than that of HIR. The mean LAVR values calculated from HIR and MBIR were 19.5 ± 12.6% and 20.4 ± 11.7%, respectively (p = 0.84). The correlation coefficients between LAVR and FEV1% that were taken from HIR and MBIR were 0.64 and 0.74, respectively (p < 0.01). MBIR is more useful than HIR for the quantitative measurements of emphysema with U-HR images.

[Usefulness of Trapezoidal Cross-injection in Aortic 3D-CTA].

PURPOSE: This study aimed to compare the contrast effects of administration via the subclavian vein, the superior vena cava and right ventricular venous tract, and the aorta in three-dimensional computed tomography angiography (3D-CTA) using one-step injection and trapezoidal cross-injection. METHOD: The subjects were 56 patients who underwent aortic 3D-CTA. In the one-step injection method, a 30-second injection of contrast medium was followed by saline injected at the same rate as the 30-ml contrast medium. In the trapezoidal cross-injection method, after injecting the contrast agent for 15 seconds, a variable mixture of the contrast agent and saline was injected for 15 seconds, followed by 20 ml saline injected at the same rate as the initial contrast agent injection. CT values were measured in the subclavian vein, superior vena cava, right ventricle, and aorta. RESULT: A significant difference was found in the subclavian vein and right ventricle, with the trapezoidal cross-injection method showing a lower CT value than the one-step injection method (p<0.01). There were no significant differences in the CT values in the superior vena cava and the aorta. CONCLUSION: The trapezoidal cross-injection method for aortic 3D-CTA produced lower CT values in venous pathways than those via the one-step injection method, but no changes were observed in the aortic CT values. These results suggest that the trapezoidal cross-injection method is useful in aortic 3D-CTA.

[Quantitative Analysis of Emphysema in Ultra-high-resolution CT by Using Deep Learning Reconstruction: Comparison with Hybrid Iterative Reconstruction].

PURPOSE: The noise generated in ultra-high-resolution computed tomography (U-HRCT) images affects the quantitative analysis of emphysema. In this study, we compared the physical properties of reconstructed images for hybrid iterative reconstruction (HIR) and deep learning reconstruction (DLR), which are reconstruction methods for reducing image noise. Using clinical evaluation, we evaluated the correlation between low attenuation volume (LAV) % obtained by CT and forced expiratory volume in 1 s per forced vital capacity (FEV1/FVC) obtained by respiratory function tests. MATERIALS AND METHODS: CT data obtained by HIR and DLR were used for analysis (matrix size: 1024´1024, slice thickness: 0.25 mm). The physical characteristics were evaluated for the modulation transfer function (MTF) and noise power spectrum (NPS). Display-field of view (D-FOV) was analyzed by varying between 300 mm and 400 mm. The clinical data evaluated the relationship between LAV% and FEV1/FVC by Spearman's correlation coefficient. RESULT: The 10% MTFs were 1.3 cycles/mm (HIR) and 1.3 cycles/mm (DLR) at D-FOV 300 mm, and 1.2 cycles/mm (HIR) and 1.1 cycles/mm (DLR) at D-FOV 400 mm. The NPS had less noise in DLR than HIR in all frequency ranges. The correlation coefficients between LAV% and FEV1/FVC were 0.64 and 0.71, respectively, in HIR and DLR. CONCLUSION: There was no difference in the resolution characteristics of HIR and DLR. DLR had better noise characteristics than HIR. The correlation between LAV% measured by HIR and DLR and FEV1/FVC is equivalent. The noise characteristics of the DLR enable the reduction of exposure to emphysema quantitative analysis by CT.

[Method for Spectral Analysis of the Respiratory Cycle Based on Dynamic Pulmonary Computed Tomography].

Dynamic pulmonary computed tomography (CT) enables morphological analyses of tumor adhesion and infiltration and functional analyses of the lungs based on four-dimensional data. However, the functional analysis requires visualization of the respiratory cycle. The aim of the present study was to investigate the utility of spectral analysis as part of the functional analysis of the lungs based on dynamic pulmonary CT. In this study, the reference curves for the respiratory cycle were obtained using measurements of all phases of respiration based on the movement of the diaphragm. The reference curves and fields of the unaffected lung were divided into three sections: upper, middle, and lower. The central position within each lung field in the axial section was used as the fixed location, and the lung field concentrations (CT values within each lung field) were measured. Using the maximum entropy (ME) method, the spectral analysis was performed for the lung field concentration curves obtained in this manner. The investigated items were the peak frequency in the power spectrum based on the ME analysis of the reference curve and the time difference from this peak frequency in the upper, middle, and lower lung field concentration curves. The time differences (median±standard deviation) from the reference values were 0.18±0.20, 0.34±0.33, and 0.34±0.35 s in the upper, middle, and lower lung fields, respectively, indicating the smallest time difference in the upper lung field. Performing spectral analysis using the ME method on lung field concentration curves enables assessment of the respiratory cycle based on dynamic pulmonary CT, and this approach is consistent with the visual assessment of the respiratory cycle.

Quantitative Emphysema Measurement On Ultra-High-Resolution CT Scans.

Purpose: To evaluate the advantages of ultra-high-resolution computed tomography (U-HRCT) scans for the quantitative measurement of emphysematous lesions over conventional HRCT scans. Materials and methods: This study included 32 smokers under routine clinical care who underwent chest CT performed by a U-HRCT scanner. Chronic obstructive pulmonary disease (COPD) was diagnosed in 13 of the 32 participants. Scan data were reconstructed by 2 different protocols: i) U-HRCT mode with a 1024×1024 matrix and 0.25-mm slice thickness and ii) conventional HRCT mode with a 512×512 matrix and 0.5-mm slice thickness. On both types of scans, lesions of emphysema were quantitatively assessed as percentage of low attenuation volume (LAV%, <-950 Hounsfield units). LAV% values determined for scan data from the U-HRCT and conventional HRCT modes were compared by the Wilcoxon matched-pairs signed rank test. The association between LAV% and forced expiratory volume in 1 s per forced vital capacity (FEV1/FVC) was assessed by the Spearman rank correlation test. Results: Mean values for LAV% determined for the U-HRCT and conventional HRCT modes were 8.9 ± 8.8% and 7.3 ± 8.4%, respectively (P<0.0001). The correlation coefficients for LAV% and FEV1/FVC on the U-HRCT and conventional HRCT modes were 0.50 and 0.49, respectively (both P<0.01). Conclusion: Compared with conventional HRCT scans, U-HRCT scans reveal emphysematous lesions in greater detail, and provide slightly increased correlation with airflow limitation.

[Development of Audio Indicator System for Respiratory Dynamic CT Imaging].

We created the device, which can conduct a radiological technologist's voice to a subject during CT scanning. For 149 lung cancer, dynamic respiratory CT were performed. 92 cases were performed using this device, the others were without this device. The respiratory cycle and respiratory amplitude were analyzed from the lung density. A stable respirating cycle was obtained by using the audio indicator system. The audio indicator system is useful for respiratory dynamic CT.

Metabolism of AM404 From Acetaminophen at Human Therapeutic Dosages in the Rat Brain.

BACKGROUND: Acetaminophen, an analgesic and antipyretic drug, has been used clinically for more than a century. Previous studies showed that acetaminophen undergoes metabolic transformations to form an analgesic compound, N-(4-hydroxyphenyl) arachidonamide (AM404), in the rodent brain. However, these studies were performed with higher concentrations of acetaminophen than are used in humans. OBJECTIVES: The aim of the present study was to examine the metabolism of AM404 from acetaminophen in the rat brain at a concentration of 20 mg/kg, which is used in therapeutic practice in humans, and to compare the pharmacokinetics between them. MATERIALS AND METHODS: We used rat brains to investigate the metabolism of AM404 from acetaminophen at concentrations (20 mg/kg) used in humans. In addition, we determined the mean pharmacokinetic parameters for acetaminophen and its metabolites, including AM404. RESULTS: The maximum plasma concentrations of acetaminophen and AM404 in the rat brain were 15.8 µg/g and 150 pg/g, respectively, with corresponding AUC0-2h values of 8.96 µg hour/g and 117 pg hour/g. The tmax for both acetaminophen and AM404 was 0.25 hour. CONCLUSIONS: These data suggest that AM404's concentration-time profile in the brain is similar to those of acetaminophen and its other metabolites. Measurement of blood acetaminophen concentration seems to reflect the concentration of the prospective bioactive substance, AM404.