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Recently developed and commercialized dual-layer flat panel detectors (DL-FPDs) with two indirect scintillators are capable of acquiring dual-energy X-ray images. However, in clinical practice, they are utilized to perform conventional radiography using diagnostic X-rays with a wide energy spectrum. The two layers of the DL-FPD may affect the obtained image quality, even when only using one layer for conventional image acquisition, and these effects are yet to be substantiated. Therefore, in this study, we quantitatively evaluated the image quality of a conventional chest radiography using DL-FPD and visually verified the characteristics of the chest anthropomorphic phantom images. The physical characteristics of the system were evaluated using the pre-sampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), for beam quality RQA 7 and RQA 9. In addition, the subjective visibility of the anthropomorphic chest phantom and simple objects images were compared with those of a conventional single-layer flat-panel detector (SL-FPD). No significant differences were found in the MTF between the SL-FPD and DL-FPD images. In addition, a higher DQE was observed at some exposure doses and in the high spatial frequency regions wherein NNPSs were lower for DL-FPD than for SL-FPD. Furthermore, no significant differences were found in the subjective visibility of the chest phantoms in each system. We concluded that the image quality of the conventional radiography acquired with DL-FPD is comparable to or better than that of the SL-FPD. [ABSTRACT FROM AUTHOR]

Ultrasound vascularity imaging provides important information for differential diagnosis of tumors. Peak-hold (PH) is a useful technique for precisely imaging small vessels by selecting a maximum brightness in each pixel through the frames obtained sequentially. To use PH successfully one needs motion compensation to reduce image blur, but out-of-plane motion cannot be avoided. To address this problem, we developed a sub-pixel motion-tracking method with out-of-plane motion detection (OPMD). It is a combination of the sum of the absolute differences (SAD) method and the Kanade-Lucas-Tomasi method and can be accurately applied to various motions. The value from OPMD (γ) is defined as a statistical value obtained from the distribution of residual values in the SAD procedure with the obtained frames. The value is ideally 0, and the frames having large γ are removed from the PH procedure. The accuracy of the proposed tracking method was found by a simulation study to be approximately 20 μm. We also found, through a phantom experiment, that the value of γ sensitively increased enough to detect out-of-plane motion. Most important, γ begins to increase before tracking errors occur. This suggests that OPMD can be used to predict tracking errors and effectively remove frames from the PH procedure. An in vivo experiment with a rabbit showed that the PH image obtained with motion tracking clearly revealed peripheral vessels that were blurred in the PH image obtained without motion tracking. We also found that the image quality becomes better when OPMD was used to remove frames including out-of-plane motion. [ABSTRACT FROM AUTHOR]

• UHRCT using the super high resolution (SHR) mode could improve measurement accuracy. • The small focal spot contributed to an accurate evaluation of a small airway. • There is a high inter- and intra-observer variability of airway measurement in SHR. Quantitative evaluations of airway dimensions through computed tomography (CT) have revealed a good correlation with airflow limitation in chronic obstructive pulmonary disease. However, large inaccuracies have been known to occur in CT airway measurements. Ultra-high-resolution CT (UHRCT) might improve measurement accuracy using precise scan modes with minimal focal spot. We assessed the effects of scan mode and focal spot size on airway measurements in UHRCT. COPDGene Ⅱ phantom, comprising a plastic tube mimicking human airway of inner diameter 3 mm, wall thickness 0.6 mm, and inclination 30 degrees was scanned at super high resolution (SHR, beam collimation of 0.25 mm × 160 rows) and high resolution (HR, beam collimation of 0.5 mm × 80 rows) modes using UHRCT. Each acquisition was performed both with small (0.4 × 0.5 mm) and large (0.6 × 1.3 mm) focal spots. The wall area percentage (WA%) was calculated as the percentage of total airway area occupied by the airway wall. Statistical analysis was performed to compare the WA% measurement errors for each scan mode and focal spot size. The WA% measurement errors in the SHR mode were 9.8% with a small focal spot and 18.8% with a large one. The measurement errors in the HR mode were 13.3% with a small focal spot and 21.4% with a large one. There were significant differences between each scan mode and focal spot size (p < 0.05). The SHR mode with a small focal spot could improve airway measurement accuracy of UHRCT. [ABSTRACT FROM AUTHOR]

The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis is technically difficult. Surgical navigation systems, combined with preoperative 3-dimensional (3D) assessment of bony impingements, can provide real-time tracking of the surgical instruments and impingement lesions. This study aims to determine the registration accuracy of the navigation system for the humerus and ulna during elbow arthroscopy. We tested the registration procedure using resin bone models of 3 actual patients with elbow osteoarthritis. We digitized bone surface points using navigation pointers under arthroscopy. We initially performed paired-point registration, digitizing 6 preset anatomical landmarks, and then refined the initial alignment with surface matching registration, digitizing 30 points. The registration accuracy for each trial was evaluated as the mean target registration error in each reference marker. Three observers repeated the registration procedure 5 times each with the 3 specimens (total, 45 trials). The median of the registration accuracy was evaluated in total (45 trials) as the accuracy of the registration procedure. The differences in the registration accuracy among the 3 observers (median of 15 trials) were also examined. The total registration accuracies were 0.96 mm for the humerus and 0.85 mm for the ulna. No significant differences were found in the registration accuracy for the humerus and ulna among the 3 observers. This arthroscopic-assisted registration procedure is sufficiently feasible and accurate for application of the navigation system to arthroscopic débridement arthroplasty in clinical settings. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Low back pain results in more global disabilities than any other condition, and intervertebral disc (IVD) degeneration is commonly involved in the etiology. Supplementation of IVDs with reparative cells is a rational strategy to address such clinical problems. We have previously developed a scaffold-free tissue-engineered construct (TEC) as a novel cell therapy system for repair of articular cartilage and meniscus. We now show the regenerative potential of adipose mesenchymal stem cells derived TEC (ADSC-TEC) for IVD degeneration using a rat tail model of total nucleotomy. The regenerative efficacy of ASDC-TEC was investigated structurally and biomechanically up to 6 months after implantation. ADSC-TEC implantation into IVDs preserved the disc height, endplate, and annulus fibrosus structure, and showed similar biomechanical characteristics to the sham group at postoperative 6 weeks. The structure of regenerated IVD was maintained until 6 months. Furthermore, ADSC-TEC implantation attenuated the impact of age-related biomechanical deterioration when assessed at 6 months post-implantation. These results demonstrate that use of ADSC-TECs can be an effective treatment for IVD degeneration. Statement of significance We developed adipose mesenchymal stem cell-derived scaffold-free tissue engineered construct (ADSC-TEC) as a novel cell therapy system. The ADSC-TEC implantation into a rat total-nucleotomized disc space regenerated intervertebral discs (IVDs) histologically and biomechanically. The regenerative capacity of the ADSC-TEC was exerted by its trophic effects on annulus fibrosus cells and the load-sharing effect at intervertebral space. Interestingly, the regenerated IVDs by the ADSC-TEC was less susceptible to the age-related deterioration than the IVDs of normal rats. Thus, the application of ADSC-TEC into the degenerated disc can be an alternative therapy for various disease associated with structural and functional failure of IVDs. [ABSTRACT FROM AUTHOR]

Background Although the elevation angle of the arm affects the range of rotation, it has not been evaluated up to the maximal abduction angle. In this study we conducted an evaluation up to maximal abduction and determined the contact patterns at the glenohumeral (GH) joint. Methods Fourteen healthy volunteers (12 men and 2 women; mean age, 26.9 years) with normal shoulders (14 right and 8 left) were instructed to rotate their shoulders at 0°, 90°, 135°, and maximal abduction for each shoulder at a time. Using 2-dimensional and 3-dimensional single-plane image registration, the internal rotation (IR), external rotation (ER), and range of motion (ROM; ie, axial rotations) at the thoracohumeral (TH) and GH joints, and the contribution ratio (%ROM = GH-ROM/TH-ROM) were calculated for each abduction. The glenoid position with respect to the humeral head was also analyzed. Results The TH-IR and TH-ER shifted toward an ER with increasing abduction angle, whereas the TH-ROM significantly decreased except at abduction between 0° and 90° (P <.001). The GH-IR and GH-ROM significantly decreased except at abduction between 0° and 90° (P <.001), but the GH-ER remained constant regardless of the abduction. The contribution ratio exceeded 80% for every abduction angle. The glenoid moved on the central and posterior areas of the humeral head at 0° and 90° abduction, respectively, and on the posterosuperior and anterosuperior areas at 135° and maximal abduction, respectively. Conclusion Our results provide new knowledge about wide axial rotation up to maximal abduction and constant GH-ER at any abduction. [ABSTRACT FROM AUTHOR]

Peripheral nerve injury is one of common traumas. Although injured peripheral nerves have the capacity to regenerate, axon regeneration proceeds slowly and functional outcomes are often poor. Pharmacological enhancement of regeneration can play an important role in increasing functional recovery. In this study, we developed a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl), one of the active forms of vitamin B12 homologues, to deliver it enough locally to the peripheral nerve injury site. We evaluated whether local administration of MeCbl at the nerve injury site was effective in promoting nerve regeneration. Electrospun nanofiber sheets gradually released MeCbl for at least 8 weeks when tested in vitro . There was no adverse effect of nanofiber sheets on function in vivo of the peripheral nervous system. Local implantation of nanofiber sheets incorporating MeCbl contributed to the recovery of the motor and sensory function, the recovery of nerve conduction velocity, and the promotion of myelination after sciatic nerve injury, without affecting plasma concentration of MeCbl. Statement of Significance Methylcobalamin (MeCbl) is a vitamin B12 analog and we previously reported its effectiveness in axonal outgrowth of neurons and differentiation of Schwann cells both in vitro and in vivo . Here we estimated the effect of local administered MeCbl with an electrospun nanofiber sheet on peripheral nerve injury. Local administration of MeCbl promoted functional recovery in a rat sciatic nerve crush injury model. These sheets are useful for nerve injury in continuity differently from artificial nerve conduits, which are useful only for nerve defects. We believe that the findings of this study are relevant to the scope of your journal and will be of interest to its readership. [ABSTRACT FROM AUTHOR]

Background It is unclear how elbow kinematics changes during forearm rotation. This study investigated in vivo 3-dimensional elbow kinematics during forearm rotation. Methods We studied 12 normal elbows using in vivo 3-dimensional computed tomography data in maximum forearm supination, neutral, and maximum pronation with the elbows in extension. We measured the motion of the radius and ulna relative to the humerus using a markerless bone registration technique and the contact area of the radiocapitellar joint, proximal radioulnar joint, and ulnohumeral joint using a proximity mapping method. Results When the forearm rotated from the supinated position to the pronated position, the radius showed significant varus rotation, internal rotation, and extension relative to the humerus. The center of the radial head significantly translated anteriorly, proximally, and laterally. The ulna significantly rotated in valgus, and the deepest point on the sagittal ridge of the trochlear notch translated medially with forearm pronation. The contact area of the radiocapitellar joint was largest in pronation. The contact area of the proximal radioulnar joint was largest in supination. The contact area of the ulnohumeral joint showed no significant change during forearm rotation. Conclusions In pronation, because of the proximal migration of the radial head, the radiocapitellar joint was most congruent compared with other positions. The proximal radioulnar joint was most congruent in supination. The ulnohumeral joint congruency was not affected by forearm rotation. This study provides useful information for understanding 3-dimensional elbow motion and joint osseous stability related to forearm rotation. [ABSTRACT FROM AUTHOR]

Background For correction of cubitus varus deformity resulting from supracondylar fracture of the humerus, we developed an operative method with use of a custom-made surgical guide, designed on the basis of 3-dimensional (3D) computer simulation with computed tomography data. The purpose of this study was to investigate the postoperative accuracy of this system in clinical cases. Methods Subjects included 17 consecutive patients (13 males and 4 females) with cubitus varus deformity after supracondylar fracture. Patients underwent 3D corrective osteotomy with use of a custom-made surgical guide. Postoperative computed tomography scan was performed after bone union diagnosis on plain radiographs, and postoperative 3D bone models were compared with preoperative simulation by surface registration technique. In addition, we evaluated radiographic parameters (humerus-elbow-wrist angle and tilting angle) and range of elbow motion at the most recent follow-up. Results Mean errors in 3D corrective osteotomy were 0.6° ± 0.7° in varus-valgus rotation, 0.8° ± 1.3° in flexion-extension rotation, 2.9° ± 2.8° in internal-external rotation, 1.7 ± 1.8 mm in anterior-posterior translation, 1.3 ± 1.8 mm in lateral-medial translation, and 7.1 ± 6.3 mm in proximal-distal translation. The mean humerus-elbow-wrist angle on plain radiographs of the affected side was 15° in varus before surgery and improved to 6° in valgus after surgery. The mean tilting angle of the affected side was 31° before surgery and improved to 40° after surgery. Conclusion The 3D correction of cubitus varus deformity was performed accurately within the allowable error limits. [ABSTRACT FROM AUTHOR]

Sarcopenia is characterized by age-associated skeletal muscle atrophy and reduced muscle strength; currently, no pharmaceutical treatment is available. Go-sha-jinki-Gan (GJG) is a traditional Japanese herbal medicine that is used to alleviate various age-related symptoms, especially motor disorders. Here, we investigated the effect of GJG on aging-associated skeletal muscle atrophy by using senescence-accelerated mice (SAMP8). Immunohistochemical and western blotting analyses clearly showed that GJG significantly reduced the loss of skeletal muscle mass and ameliorated the increase in slow skeletal muscle fibers in SAMP8 mice compared to control mice. The expression levels of Akt and GSK-3β, the phosphorylation of FoxO4, and the phosphorylations of AMPK and mitochondrial-related transcription factors such as PGC-1α were suppressed, while the expression of MuRF1 increased in SAMP8 mice, but approximated that in senescence-accelerated aging-resistant (SAMR1) mice after GJG treatment. We demonstrate for the first time that GJG has a therapeutic effect against sarcopenia. [ABSTRACT FROM AUTHOR]

Purpose To examine 3-dimensional carpal alignment and radioscaphoid joint (RSJ) congruity among normal wrists and those with Lichtman stage III Kienböck disease or scapholunate dislocation (SLD). Methods We conducted 3-dimensional analysis based on computed tomographic data to compare 10 wrists of stage III Kienböck disease (5 IIIa and 5 IIIb) with 5 normal wrists and 3 wrists with SLD. A markerless bone registration technique was used to investigate the 3-dimensional position of the scaphoid relative to the radius. To evaluate RSJ congruency, the inferred contact area between the scaphoid proximal pole and the distal radius was calculated from 3-dimensional bone models. Results The scaphoid position was not significantly different from normal wrists in stage IIIa Kienböck disease. Stage IIIb Kienböck disease was meaningfully associated with a flexed scaphoid and proximal translation of the centroid, but not dorsal translation of the scaphoid proximal pole, where RSJ congruity was preserved. With SLD, the scaphoid flexed to the same extent as that in stage IIIb Kienböck disease, and the proximal pole translated dorsally together with the capitate, producing RSJ incongruity. Conclusions The patterns of carpal collapse differed between stage IIIb Kienböck disease and SLD in terms of RSJ congruity. Our study showed that stage IIIb Kienböck disease did not involve dorsal subluxation of the scaphoid proximal pole and that RSJ congruity was retained, unlike SLD. Clinical relevance Our results suggest that carpal collapse in Kienböck disease is not associated with RSJ incongruity, which may explain why there are asymptomatic patients with Kienböck disease and carpal collapse. Type of study/level of evidence Diagnostic II. [ABSTRACT FROM AUTHOR]