Imaging findings of isolated congenital middle ear malformation on high-resolution computed tomography.

PURPOSE: This study aims to analyze the imaging features of isolated congenital middle ear malformation (CMEM) on high-resolution computed tomography (HRCT). METHODS: We retrospectively collected patients with surgically confirmed diagnosis of isolated CMEM in our hospital between January 2018 and June 2023. All patients underwent HRCT before surgery. The preoperative imaging findings were analyzed by neuroradiologists with full knowledge of the intraoperative findings. RESULTS: 37 patients were included in this study, including 25 males and 12 females, with a median age of 16 years. A total of 44 ears underwent surgery. The most commonly affected structures were incudostapedial joint, incus long process, and stapes superstructure, followed by stapes footplate, oval window, incudomalleolar join, tympanic segment of the facial nerve canal, incus body, incus short process and malleus. All incus defect/hypoplasia/malposition, stapes superstructure deformity, malleus deformity, incudostapedial joint discontinuity, and facial nerve canal malposition/abnormal bifurcation could be observed on HRCT. Additionally, 96.0% of stapes superstructure defect, 85.7% of oval window atresia, and 41.7% of incudomalleolar joint fusion, could be visualized on HRCT. HRCT could not show ossicular soft tissue pseudo-connection and stapes footplate fixation. CONCLUSIONS: Preoperative HRCT is an important tool for diagnosing isolated CMEM. The advantages of HRCT lie in its ability to detect ossicular defects/deformities, incudostapedial joint discontinuity, oval window atresia, and facial nerve abnormalities. However, it has a low detection rate for incudomalleolar joint fusion and cannot show ossicular soft tissue pseudo-connection and stapes footplate fixation.

Imaging features of pediatric meningiomas: emphasis on unusual locations.

PURPOSE: This article aims to analyze pediatric meningioma's imaging characteristics, especially those in unusual locations. METHODS: Pediatric patients with pathologically confirmed meningiomas at our hospital from January 2010 to January 2024 were enrolled. Meningiomas located in the cerebral convexity, parasagittal falcine region, anterior skull base, middle skull base, sphenoid ridge, cerebellopontine angle (CPA), olfactory groove, or juxtasella were considered in usual locations. Meningiomas found in other areas were considered in unusual locations. Clinical information, pathology results, and imaging features of pediatric meningiomas in usual and usual locations were analyzed and compared. RESULTS: A total of 18 patients (19 meningiomas) were enrolled, including 14 males and 4 females, with an average age of 14 years (ranging from 6 to 18 years). A total of 12 (63.2%) meningiomas were in the unusual location, including four (33.3%) were intraparenchymal, four (33.3%) were intraventricular, two (16.7%) were intraosseous, one (8.3%) case was in the paranasal sinus, and one (8.3%) was intraspinal. The meningiomas in unusual locations usually lacked the meningeal tail sign, and the misdiagnosis rate on preoperative imaging was significantly higher than that of meningiomas in usual locations. CONCLUSION: Pediatric meningiomas are prone to occur in unusual locations. When they occur in usual locations, they often lack typical radiographic features of meningiomas, leading to potential misdiagnosis before surgery. Recognition of the imaging characteristics of meningiomas in unusual locations in children may facilitate accurate preoperative imaging diagnosis.

The difference of dynamic elasticity characteristics and stroke effect between two types of new material seamed plastic table tennis ball.

The diameter and weight of different brands of table tennis ball will affect the ball's elasticity and stroke. The purpose of this study is to analyze the difference of the dynamic elasticity and stroke effect between the two brands of new plastic ball. A self-made experiment was designed to test the dynamic elasticity characteristics of DHS D40 + and Nittaku 40+. Table tennis players (N = 18) were randomly selected from the China Table Tennis College (Mage = 15.16 ± 2.41; Mheight = 1.59 ± 0.32 m; Mweight = 45.72 ± 5.17 kg). Each participant was righthand shake-hands grip. A speedometer was used to record the ball speed and a high-speed camera was used to measure the spin speed. Data normality was verified by using the Kolmogorov-Smirnov test. The independent t-test was conducted to assess the differences of the dynamic elasticity and stroke effect between the two types of plastic ball. Results showed that the rebound speed and decrement rate of DHS D40 + and Nittaku 40 + both increased with the increased falling speed, respectively. When falling at high speed, there was a significant difference of dynamic elasticity between DHS D40 + and Nittaku 40+ (p < 0.01). There was also a significant difference in the ball speed and spin speed between the two types of new material seamed plastic ball during the backhand backspin stroke (p = 0.041, p = 0.022, respectively), and the ball speed and spin speed of DHS D40 + were higher than that of Nittaku 40 + ball. Compared with the DHS D40+, the Nittaku 40 + has a faster rebound speed, higher rebound height, and better dynamic elasticity. Therefore, under same striking conditions, when hitting the Nittaku 40 + ball, players need to increase the swing distance and hit the ball with more strength to improve the ball speed and rotation speed; increase the spin and decrease the ball's rebound height of the serve.

Study of naphthopyran derivatives: structure and photochromic properties in solution and in polymer film.

Four naphthopyran derivatives, namely, 3,3-bis(naphthalen-1-yl)-3H-naphtho[2,1-b]pyran, C33H22O, NP1, 3,3-bis([1,1'-biphenyl]-4-yl)-3H-naphtho[2,1-b]pyran, C37H26O, NP2, 3,3-bis(4-phenoxyphenyl)-3H-naphtho[2,1-b]pyran, C37H26O2, NP3, and 3,3-bis(4-methoxy-2-methylphenyl)-3H-naphtho[2,1-b]pyran, C29H26O3, NP4, were synthesized and their photochromic properties investigated. NP1-NP4 exhibited good photochromism in different solutions and in poly(methyl methacrylate) (PMMA) film under UV light irradiation. Solvatochromism and the electronic and steric effects of the substituent group on photochromism were analyzed and decolouration curves were found to fit a monoexponential kinetic decay in most cases. Single-crystal X-ray analysis of NP1 and NP2 revealed the structure-property relationships. Good fatigue resistance of NP1, both in solution and in the PMMA film, endows it with potential value for applications.