Inveon mm system

The collected bone tissues were fixed in 4% paraformaldehyde for 48 h and stored in 75% ethanol. The specimens were scanned using an Inveon MM system (Siemens, Munich, Germany). Images were obtained at voltage of 80 kV, current of 500 μA, effective pixel size of 8.82 μm, and exposure time of 1,500 ms of every 360 rotational steps. For quantification and analyses of the images, bone mineral density (BMD), bone volume/total volume (BV/TV), trabecular number (Tb.N), and trabecular spacing (Tb. Sp) parameters were analyzed using Image‐Pro Plus software (Media Cybernetics, Rockville, MD).

Following the biomechanical testing, another unilateral femur of each animal was prepared for the micro-CT scanning. Micro-CT was performed using an Inveon MM system (Siemens, Munich, Germany). Specimens were located and scanned in whole, with 360° rotation in 360 equiangular steps. Images were acquired at an effective pixel size of 8.99 μm, voltage of 80 kV, current of 500 μA and exposure time of 1500 ms. The images consisted of 1024 slices, with a voxel size of 8.99 μm × 8.99 μm × 8.99 μm. Two-dimensional images were used to construct 3D reconstructions using Inveon Research Workplace 3.0 software (Siemens). After acquiring the 3D images, the peri-implant volume-of-interest of 1 mm was established manually, and the threshold value was adjusted appropriately to distinguish trabecular bone from bone marrow. Inveon Research Workplace 3.0 software (Siemens) was used to automatically compute BV/TV, BMD and the following trabecular bone morphological parameters: Tb.N, Tb.Sp and Tb.Th44 (link)45 (link).

Two-month-old female Sprague–Dawley (SD) rats, weighing 200–225 g, were purchased from the Laboratory Animal Center of Sun Yat-Sen University (n = 9 per group). Rats were maintained in a pathogen-free facility on a 12-h light/dark cycle with water and food provided ad libitum. Rats were sham-operated (sham) or ovariectomized (OVX). The OVX rats presented osteoporosis as described previously [23 (link)]. Rats were allowed 3 months to recover from the ovariectomy surgery and then sacrificed for the related assays [24 (link)].
To evaluate the mass and microarchitecture of the bone between different groups, micro-CT was performed using an Inveon MM system (Siemens). Images were acquired at an effective pixel size of 8.82 lm, a voltage of 80 kV, a current of 500 lA and an exposure time of 1500 ms in each of the 360 rotational steps. The parameters of bone volume/total volume (BV/TV) and trabecular number (Tb.N) in the trabecular region (1–2 mm distal to the proximal epiphysis) were calculated using an Inveon Research Workplace (Siemens) according to the guidelines set by the American Society for Bone and Mineral Research. In addition, sections (5-mm thickness) of femur specimens from the different groups were stained with H&E to evaluate bone loss in OVX rats.

To investigate differences in bone mass and microarchitecture among the groups, the micro-computed tomography Inveon MM system (Siemens, Munich, Germany) was used to analyze bone specimens. Briefly, images of rat proximal femur, centrum, and mandible were scanned with 8.82 μm pixel size, 220 μA current, 60 kV voltage, and 1500 ms exposure time [46 (link)]. Bone histomorphometry parameters and BMD (1–2 mm distal to the proximal epiphysis) were calculated using an Inveon Research Workplace (Siemens) in accordance with common guidelines [47 (link)].

Rats were euthanized on days 3 and 14 to evaluate bone mineral density (BMD. An Inveon MM system (Siemens, Munich, Germany) was used for micro-CT analysis. Images were obtained at a pixel size of 8.82 μm, exposure time of 1500 ms, voltage of 80 kV, and current of 500 µA for each of the 360 rotational steps. Cross-sections were used for general viewing, but vertical sections were used for quantitative analysis. The vertical reference plane is the plane formed by the proximal and distant middle cusp of the first molars and the root tip of the tooth. The horizontal reference plane is located in the one-third of the root near the neck of the tooth and perpendicular to the vertical plane. The region (200 μm width ×200 μm thickness × 800 μm length) of alveolar bone adjacent to the neck of the distal palatal root was regarded as the compression side.

Three-dimensional reconstruction of the hind knee and ankle joints were obtained by Micro-CT examination (Inveon MM system, Siemens Preclinical Solutions) at the end of treatment. Briefly, after the mice in different groups being killed using ether anesthesia, the hind limbs were removed and fixed in 4% paraformaldehyde. The samples were scanned with micro-CT, and images were acquired at an effective pixel size of 8.5 μm, voltage of 80 kV, current of 500 μA and exposure time of 1000 ms in each of the 360 rotational steps. Parameter were calculated using an Inveon Research Workplace (Siemens Medical Solutions) using manufacturer-supplied software as follows: bone volume/total volume (bone volume fraction, BV/TV), trabecular number (Tb. N.), trabecular thickness (Tb. Th.), and trabecular spacing (Tb. Sp.).

After 21 days of growth in the kidney capsule, the collected mouse kidneys were fixed in 4% PFA overnight at room temperature. Then they were scanned using an Inveon MM system (Siemens, Munich, Germany) to observe the morphology of the root furcation. Images were obtained at 80 kV (voltage), 500 μA (current), 10 μm (pixel size), and 1500 ms (exposure time for each 360 rotational steps). Images were captured using the Inveon MM software.