Impact of beam collimation of z-overscanning on dose to the lens and thyroid gland in paediatric thoracic computed tomography imaging.

BACKGROUND: Adaptive collimation reduces the dose deposited outside the imaged volume along the z-axis. An increase in the dose deposited outside the imaged volume (to the lens and thyroid) in the z-axis direction is a concern in paediatric computed tomography (CT). OBJECTIVE: To compare the dose deposited outside the imaged volume (to the lens and thyroid) between 40-mm and 80-mm collimation during thoracic paediatric helical CT. MATERIALS AND METHODS: We used anthropomorphic phantoms of newborns and 5-year-olds with 40-mm and 80-mm collimation during helical CT. We compared the measured dose deposited outside the imaged volume using optically stimulated luminescence dosimeters (OSLD) at the surfaces of the lens and thyroid and the image noise between the 40-mm and 80-mm collimations. RESULTS: There were significant differences in the dose deposited outside the imaged volume (to the lens and thyroid) between the 40-mm and 80-mm collimations for both phantoms (P < 0.01). CONCLUSION: Compared with that observed for 80-mm collimation in helical CT scans of the paediatric thorax, the dose deposited outside the imaged volume (to the lens and thyroid) was significantly lower in newborns and 5-year-olds with 40-mm collimation.

Effectiveness of low tube voltage scan in the exposure dose for lenses during paediatric thoracic CT examination: anthropomorphic phantoms study.

To determine whether using lower-tube voltage reduces the scattered dose for the lens during paediatric thoracic computed tomography (CT). Two paediatric anthropomorphic phantoms (ATOM Phantom, CIRS, Norfolk, Virginia, USA) representing a newborn and 5-year-old were placed on the gantry of CT scanner, and optically stimulated luminescence dosemeters were placed on the left and right lenses, in front of the left and right thyroid glands, in front of the left and right mammary glands, and in front of and behind the mammary gland level and we measured scattered dose of the optically stimulated luminescence dosemeter was compared for each phantom between 80 and 120 kVp. Significant differences were observed in the scatter doses for the lens between 80 and 120 kVp (p < 0.01). Compared with the 120 kVp scan, the scatter doses for the lens were ~15-40% lower in newborn and 5-year-olds using the 80 kVp scan during paediatric CT.

Evaluation of Patient Positioning during Digital Tomosynthesis and Reconstruction Algorithms for Ilizarov Frames: A Phantom Study.

AIM: Metallic components from circular external fixators, including the Ilizarov frame, cause artefacts on X-rays and obstruct clear visualisation of bone detail. We evaluated the ability of tomosynthesis to reduce interference on radiographs caused by metal artefacts and developed an optimal image acquisition method for such cases. MATERIALS AND METHODS: An Ilizarov frame phantom was constructed using rods placed on the bone for the purpose to evaluate the benefits of tomosynthesis. Distances between the rod and bone and the angle between the rod and X-ray tube orbit were set at three different levels. Filtered backprojection images were reconstructed using two different features of the reconstruction function: THICKNESS-- (CONTRAST4) and THICKNESS++ (METAL4); the first is suitable for improving contrast and the second is suitable for metal artefacts. The peak signal-to-noise ratio (PSNR) was used during image evaluation to determine the influence of the metallic rod on bone structure visibility. RESULTS: The PSNR increased as the angle between the metal rod and the X-ray tube orbit and the distance between the metallic rod and bone increased. The PSNR was larger when using THICKNESS-- (CONTRAST4) than when using THICKNESS++ (METAL4). CONCLUSION: The optimal reconstruction function and image acquisition determined using the metallic rod in this study suggest that quality equal to that without the metallic rod can be obtained. CLINICAL SIGNIFICANCE: We describe an optimised method for image acquisition without unnecessary acquisition repetition and unreasonable posture changes when the bone cannot be adequately visualised. HOW TO CITE THIS ARTICLE: Abe Y, Shimada M, Takeda Y, et al. Evaluation of Patient Positioning during Digital Tomosynthesis and Reconstruction Algorithms for Ilizarov Frames: A Phantom Study. Strategies Trauma Limb Reconstr 2020;15(1):1-6.

Radiological improvement by tocilizumab in polyarticular juvenile idiopathic arthritis.

Recent advances in biologic therapy have enabled reduction of the progression of destructive arthritis in rheumatoid arthritis. Once destroyed, however, the affected bones and cartilage are not fully repaired. We describe the case of an 8-year-old girl with anti-citrullinated peptide antibody (ACPA)-positive polyarticular juvenile idiopathic arthritis (p-JIA). Destructive arthritis progressed during combination therapy with infliximab, methotrexate, mizoribine and prednisolone. Clinical remission was achieved, however, after switching the biologic agent to tocilizumab, a humanized monoclonal antibody to interleukin-6 receptor. Both bone erosion and bone marrow edema on magnetic resonance imaging were repaired in association with restoration of joint spaces. Furthermore, there was no relapse of arthritis on weekly methotrexate alone for 2 years after discontinuation of the tocilizumab. Tocilizumab led to radiological repair of both bone and cartilage destruction and long-term biologics-free remission in a patient with ACPA-positive p-JIA, and should be considered for tumor necrosis factor inhibitor-resistant cases.

Successful treatment of immune tolerance induction with rituximab in a patient with severe hemophilia B and inhibitor.

Inhibitor development is one of the major problems in hemophilia patients. Whereas the inhibitor incidence in hemophilia A is estimated to be as high as 25-30%, it appears to be less frequent in hemophilia B, occurring in about 1-3% of hemophilia B patients. There are only a few case reports about immune tolerance induction (ITI) for hemophilia B patients. The present report describes ITI with rituximab in a patient with severe hemophilia B and inhibitor. The patient was diagnosed with severe hemophilia B at 9 months. He received prophylactic replacement therapy with plasma-derived factor IX (pd FIX). After 19 exposure days, inhibitor of factor IX was detected in his plasma, and replacement therapy was stopped. However, as he suffered from intracranial hemorrhage at the age of 1 year, he underwent first ITI at the age of 1 year. Unfortunately, this failed to reduce the level of the inhibitor, and this strategy was stopped after 2 years. Second ITI with pd FIX also failed. At the age of 14 years, ITI with rituximab was performed after obtaining informed consent. The patient received rituximab 375 mg/m once a week for four doses and received 40 u/kg of pd FIX every day. At 4 weeks after the start of ITI with rituximab, the level of the inhibitor of factor IX was diminished and was undetectable for 1 year after therapy. In this patient, ITI with rituximab was well tolerated and effective. This method should be considered for patients with hemophilia B and inhibitor.

Genomic basis of aromatase excess syndrome: recombination- and replication-mediated rearrangements leading to CYP19A1 overexpression.

CONTEXT: Genomic rearrangements at 15q21 have been shown to cause overexpression of CYP19A1 and resultant aromatase excess syndrome (AEXS). However, mutation spectrum, clinical consequences, and underlying mechanisms of these rearrangements remain to be elucidated. OBJECTIVE: The aim of the study was to clarify such unsolved matters. DESIGN, SETTING, AND METHODS: We characterized six new rearrangements and investigated clinical outcome and local genomic environments of these rearrangements and of three previously reported duplications/deletions. RESULTS: Novel rearrangements included simple duplication involving exons 1-10 of CYP19A1 and simple and complex rearrangements that presumably generated chimeric genes consisting of the coding region of CYP19A1 and promoter-associated exons of neighboring genes. Clinical severities were primarily determined by the copy number of CYP19A1 and the property of the fused promoters. Sequences at the fusion junctions suggested nonallelic homologous recombination, nonhomologous end-joining, and replication-based errors as the underlying mechanisms. The breakpoint-flanking regions were not enriched with GC content, palindromes, noncanonical DNA structures, or known rearrangement-associated motifs. The rearrangements resided in early-replicating segments. CONCLUSIONS: These results indicate that AEXS is caused by duplications involving CYP19A1 and simple and complex rearrangements that presumably lead to the usage of cryptic promoters of several neighboring genes. Our data support the notion that phenotypes depend on the dosage of CYP19A1 and the characteristics of the fused promoters. Furthermore, we show that the rearrangements in AEXS are generated by both recombination- and replication-mediated mechanisms, independent of the known rearrangement-inducing DNA features or late-replication timing. Thus, AEXS represents a unique model for human genomic disorders.

Effectiveness of the new injection program 'saline test injection mode' for use power injector in pediatric contrast CT.

To improve the safety of the use of a power injector for pediatric contrast CT, we newly developed a saline test injection mode for a power injector and investigated its usefulness. We used an injection route and investigated the relationship of the injection pressure to the injection rate of saline and the contrast medium. From this relationship, we investigated it was possible to estimate the change of pressure injection of contrast medium from the pressure change of saline injection. The correlation between the saline test injection pressure and the contrast medium injection pressure was investigated in 64 clinical cases. The detection rate of side effects from the saline test injection was investigated in 473 patients. Regarding the correlation between the injection rate and pressure for both saline and contrast, the pressure rose as the rate increased. The contrast medium injection pressure could be estimated from the correlation observed with saline. The clinical data were obtained had a relationship similar to that with phantom data. The detection rate of side effects from the saline test injection was 4.4% in the clinical cases. In these cases, examinations were completed by re-establishing an injection route or administering hypnotics. Our results suggest that contrast medium pressure can be estimated from a saline test injection, thus aiding in prediction of the risk of injection abnormality. Reactions to injections could be observed in the present study, facilitating the prevention of examination failure. Countermeasures can be taken against the cause of the reaction, and the examination can be performed after confirming the absence of a reaction to injection. Therefore, a saline test injection may be useful in pediatric contrast CT.

Comparison of anti-scatter grids for digital imaging with use of a direct-conversion flat-panel detector.

Our purpose in this study was to establish a selection standard for anti-scatter grids for a direct conversion flat-panel detector (FPD) system. As indices for grid evaluation, we calculated the selectivity, Bucky factor, and the signal-to-noise ratio improvement factor (SIF) by measuring rates of scatter transmission, primary transmission, and total transmission (based on the digitally displayed measurement values of the FPD system), using 4 acrylic phantoms of different thicknesses. The results showed that the SIF was less than 1.0 when the phantom thickness was 5 cm. When the phantom thickness was 25 cm and the grid ratio was 16:1, the SIF was 1.505 and 1.518 (maximum value) at 90 and 120 kV, respectively. Compared with the grid ratio of 12:1, the SIF at the grid ratio 16:1 was improved by 6.1% at 90 kV, and by 7.0% at 120 kV. In a direct-conversion FPD system, the grid ratio of 16:1 is considered adequate for eliminating the scattered-radiation effect when much scattered radiation is present, such as with a thick imaged object or a high X-ray tube voltage.

Structural noise from automatic exposure control device and its relationship to X-ray tube voltage used for calibration of a flat-panel detector system.

In flat-panel detector (FPD) systems, the ion-chamber dosimeters used for automatic exposure control (AEC), which are placed between the detector and the source, should not affect clinical images because of FPD gain correction, but can sometimes still introduce fixed-pattern noise. In this study, we investigated whether such artifacts were caused by structural noise from the AEC detector on the basis of the noise power spectrum (NPS) and the mean square error (MSE) of FPD images taken at various tube voltages either with or without the AEC detector. When the NPS was measured without the AEC detector, the NPS did not increase in the low special-frequency band at all radiation qualities tested, irrespective of X-ray calibration tube voltages. However, when the NPS was measured while the AEC detector was used, the NPS increased in the low special-frequency band at all radiation qualities when the X-ray calibration tube voltages were at low levels. Similarly, the MSE increased when the X-ray calibration tube voltages were at low levels. From these results, artifacts in the AEC detector appear to be suppressed when a radiation quality of approximately 90 kV is used at four different standardized radiations quality (RQA3, RQA5, RQA7, and RQA9).

Prospective study of methotrexate treatment for rheumatoid arthritis treated legitimately according to the government recommended 8 mg/week dose.

Clinical squeal of the treatment of rheumatoid arthritis patients with methotrexate (MTX) according to the Japanese government recommended dose of 8 mg/week was evaluated prospectively. A total of 176 patients with active RA attending Konan Kakogawa Hospital and Kobe University Hospital were enrolled. Patients' profile at the start of study was Class 2.0 +/- 1.1 and X-ray stage 2.6 +/- 1.0. The effects of MTX treatment were evaluated by the American College of Rheumatology (ACR) core set, disease activity score of 28 joints (DAS28), and European League Against Rheumatism (EULAR) response criteria. A modified Sharp method was used to evaluate the radiographs. The improvement in the clinical signs and symptoms of the ACR core set was maintained for a 24-month period (p < 0.05). The ACR20/50/70 and DAS28 were also improved at the 12- and 24-month assessments. However, 82 of 130 patients (63.5%) were found to be nonresponders at 24 months of MTX therapy, as evaluated by EULAR response criteria. The X-ray study showed that joint destruction progressed despite the treatment. Thus, long-term MTX treatment performed in accordance with the Japanese 8 mg/week regimen appears to be favorable in terms of the signs and symptoms of RA; however, it is clearly insufficient for and cannot halt the progression of rheumatic joint destruction.

Total knee arthroplasty for rheumatoid knee with bilateral, severe flexion contracture: report of three cases.

The treatment of patients with severe flexion contracture of the rheumatoid knee, deprived of ambulation for long periods of time, is challenging. Based on three cases, we indicate the potential risks of posterior dislocation of the knee after total knee arthroplasty. In this pathological condition, surgeons must carefully select the type of implant in order to avoid this serious complication. We also emphasize the importance of working on disuse muscle atrophy of trunk (back, abdominal) and lower limbs, both of which play an integral role in ambulation. The personality of each rheumatoid patient should be carefully considered when considering surgical and rehabilitation options.

Spectral evidence and DFT calculations on the formation of Bis(2,2'-bipyridine)platinum(II)-N-base adducts.

The formation of 1:1 adducts of Pt(bpy)2(2+) (bpy = 2,2'-bipyridine) with various N bases (B) has been ascertained in water at ambient temperature by spectrophotometric titration and electrospray ionization mass spectroscopy. A pseudo-five-coordinated complex, [Pt(bpy)2(B)](2+) with a monodentating bpy, is proposed based on density functional theory calculation. The formation constants (Kc) increase with the nucleophilicity of B except for sterically hindered N-bases, indicating an associative ligand-substitution mechanism.

[Bedside chest radiography and optimization of radiographic conditions in the NICU with the Fuji Computed Radiography System].

We devised an application that uses the "Maximum value reading method (AutoIV)" for bedside chest radiography in a neonatal intensive care unit (NICU) that used the Fuji Computed Radiography (FCR) System. The application, named AutoIV-N, uses the relationship for density correction between radiographic conditions (mAs) and the Display Parameter (GS). GS=f (mAs) can be considered the relationship that connects FCR and the X-ray generator. When AutoIV-N is used, radiographic image contrast does not change. Further, radiographic image density fluctuation can be eliminated by random elements such as X-ray output fluctuation of the X-ray generator and the decline of photo-stimulated luminescence caused by fading of the imaging plate. Accordingly, image recording that is suitable for follow-up chest radiography is made possible. We choose nine patients and performed a comparison of radiographic density fluctuation in AutoIV-N and Fix. AutoIV-N was found to be more stable than Fix. It is possible to use the radiographic imaging condition that is optimized for all patients in the NICU by AutoIV-N. This facilitates radiation exposure optimization in medicine. (Article in Japanese).

Four Japanese patients with adrenal hypoplasia congenita and hypogonadotropic hypogonadism caused by DAX-1 gene mutations: mutant DAX-1 failed to repress steroidogenic acute regulatory protein (StAR) and luteinizing hormone beta-subunit gene promoter activity.

Mutations of DSS (dosage sensitive sex reversal)-AHC critical region on the X chromosome, gene 1 DAX-1(NROB1)] results in X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). Here we report four Japanese patients with AHC and HHG caused by the mutations of the DAX-1 gene. All patients manifested adrenal crisis at early childhood. Three patients did not show any pubertal sign and were diagnosed as having HHG. One patient manifested spontaneous pubertal development at 17 years of age. Nevertheless, his puberty did not develop further and his gonadotropin and testosterone levels decreased thereafter. Therefore, he was also diagnosed as having HHG. We performed testicular biopsy in another patient with HHG. Histological examination demonstrated Sertoli cell hypoplasia and no sperm formation in the seminiferous tubules. Molecular analysis demonstrated two novel point mutations (V269D and L278R) in two patients. Transient transfection assays showed that all these mutations (V269D, L271X, L278R, and Q395X) abolished the repression activity to both StAR and LHbeta gene promoter activation. In conclusion, we reported patients with AHC and HHG caused by the loss of function mutations of the DAX-1 gene.

Long-term results of open elbow synovectomy for rheumatoid arthritis.

Long-term results of open synovectomy of the elbow with rheumatoid arthritis (RA) were reviewed in 15 elbows. The subjects were evaluated at two time points with average follow-up periods of 4 and 8.7 years, and the results were compared between the two follow-ups. The Mayo Clinic performance score showed significant improvement in pain, motion, and daily function from the intermediate to the long-term follow-up. Overall results were satisfactory with little time-dependent deterioration in radiological grading, confirming the long-term effectiveness of this procedure.

The effectiveness of RA wrist fusion using Beta-TCP without autogenous iliac bone grafting: a report of four cases.

Wrist arthrodesis is indicated for the rheumatoid hand especially in cases with severe destruction of the carpal bones. In the arthrodesis procedure for the rheumatoid wrist, autogenous iliac bone grafting is required in most cases. However, autogenous iliac bone graft necessitates the additional surgical intervention, and can be associated with the problem of inadequate bony quality or quantity. It is thought that use of the artificial bone substitute in the procedure can lessen the surgical morbidity while supplying the consistent material without shortage of graft quantity. We have performed arthrodesis of the rheumatoid wrist using beta-TCP for four patients. Clinical results of these patients were satisfactory both in pain relief and functional improvement with complete bony healing. Therefore, this procedure seems to be an effective option for the rheumatoid wrist with severe destructive changes.

Designing cyclophane-based molecular wire sensors.

We propose a model molecular wire sensor that can detect zerovalent chromium by a strong increase in conductance when included in a metal-molecule-metal junction. An essential part of the sensor is a paracyclophane unit that binds to the metal atom. The nature and the energies of the molecular orbitals change drastically after the complex is formed, resulting in a 10- to 12-fold increase in conductance.

Surface potential switching by metal ion complexation/decomplexation using bipyridinethiolate monolayers on gold.

Surface potential switching on gold(111) surfaces is induced by complexation/decomplexation reactions of a bipyridine (BP) derivative and palladium(II) chloride, as observed by Kelvin probe force microscopy (KFM). On the basis of the theoretical predictions, a 4-(5-phenylethynyl-2,2'-bipyridine-5'-yl-ethynyl)benzenethiol (PhBP) derivative was synthesized and used as an active monolayer to catch transition metal ions. By using the microcontact printing (CP) technique, micron-size patterned PhBP monolayers, which act as effective hosts to coordinate palladium(II) chloride, were prepared on gold(111) surfaces. The KFM signal decreases by complexation of the Pd(II) chloride in PhBP monolayers and is recovered by removal of Pd ions using an ethylenediamine solution, as confirmed by X-ray photoelectron spectroscopy. This process is reversible, indicating that the surface potential switching is realized by complexation/decomplexation of Pd(II). A CP PhBP monolayer, when it detects the target palladium ion, shows sensitivity for the picomolar level detection judged from surface potential changes in KFM measurements. The dipole moment estimated by the surface potentials is much smaller than the calculated value, indicating that mechanisms for the reduction of the surface dipole moment exist in real monolayers prepared by the CP method.

Molecular switch on a metal surface.

We report a theoretical study for the conformational switching of molecules on Au(111) surface in the presence of an applied electric field. Ab initio calculations for N-(2-mercaptoethyl)benzamide indicate that this molecule, when adsorbed, can exist as two stable conformers of nearly equal energies, but the dipoles point in reverse directions with respect to the surface. An electric field can be used to "switch" one conformer to the other, and during this process, there is an abrupt change in the height of the molecule from the surface. This change is expected to cause a conductance switching in the system. Further calculations for N-(2-mercaptoethyl)-4-phenylazobenzamide suggest that the experimentally observed phase switching of this molecule is associated with a conformational change accompanied by dipole reversal.

Thermal hysteresis loop of the spin-state in nanoparticles of transition metal complexes: Monte Carlo simulations on an Ising-like model.

Theoretical investigation with Monte Carlo simulations predicts that thermal spin-switching hysteresis of transition-metal complexes appears even in nanoparticles, but the hysteresis width does not depend only on the interaction strength between molecules but also strongly on the shape and size of the particles.