Synchrotron-based micro-CT imaging of the human lung acinus.

Structural data about the human lung fine structure are mainly based on stereological methods applied to serial sections. As these methods utilize 2D images, which are often not contiguous, they suffer from inaccuracies which are overcome by analysis of 3D micro-CT images of the never-sectioned specimen. The purpose of our study was to generate a complete data set of the intact three-dimensional architecture of the human acinus using high-resolution synchrotron-based micro-CT (synMCT). A human lung was inflation-fixed by formaldehyde ventilation and then scanned in a 64-slice CT over its apex to base extent. Lung samples (8-mm diameter, 10-mm height, N = 12) were punched out, stained with osmium tetroxide, and scanned using synMCT at (4 µm)(3) voxel size. The lung functional unit (acinus, N = 8) was segmented from the 3D tomographic image using an automated tree-analysis software program. Morphometric data of the lung were analyzed by ANOVA. Intra-acinar airways branching occurred over 11 generations. The mean acinar volume was 131.3 ± 29.2 mm(3) (range, 92.5-171.3 mm(3)) and the mean acinar surface was calculated with 1012 ± 26 cm(2). The airway internal diameter (starting from the bronchiolus terminalis) decreases distally from 0.66 ± 0.04 mm to 0.34 ± 0.06 mm (P < 0.001) and remains constant after the seventh generation (P < 0.5). The length of each generation ranges between 0.52 and 0.93 mm and did not show significant differences between the second and eleventh generation. The branching angle between daughter branches varies between 113-degree and 134-degree without significant differences between the generations (P < 0.3). This study demonstrates the feasibility of quantitating the 3D structure of the human acinus at the spatial resolution readily achievable using synMCT.

Treatment of a double nonunion of the femur by rhBMP-2.

A 49-year-old patient sustained an ipsilateral fracture of the lateral femoral neck and distal femoral shaft, which were treated with a long intramedullary nail with a hip screw component. Both fractures did not heal, and both nonunion sites were revised by reosteosynthesis with a dynamic hip screw for the femoral neck and a locked intramedullary nail for the shaft region combined with autogenous bone grafting at both sites. At 14 months from injury and after 2 operations, both nonunions persisted. At a third surgery, 1 kit of recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge was applied to each site, without any modification of the osteosynthesis or additional bone grafting. The lateral femoral neck and the femoral shaft consolidated 24 and 30 weeks, respectively, after the rhBMP-2 application, and the patient resumed his work as industrial worker after 7 months after his last surgery. We believe this is the first study to report the successful use of 2 kits of rhBMP-2 in a double nonunion of the femur.

Three-dimensional imaging and morphometric analysis of alveolar tissue from microfocal X-ray-computed tomography.

We evaluated microfocal X-ray-computed tomography (micro-CT) as a method to visualize lung architecture two and three dimensionally and to obtain morphometric data. Inflated porcine lungs were fixed by formaldehyde ventilation. Tissue samples (8-mm diameter, 10-mm height) were stained with osmium tetroxide, and 400 projection images (1,024 x 1,024 pixel) were obtained. Continuous isometric micro-CT scans (voxel size 9 microm) were acquired to reconstruct two- and three-dimensional images. Tissue samples were sectioned (8-microm thickness) for histological analysis. Alveolar surface density and mean linear intercept were assessed by stereology-based morphometry in micro-CT scans and corresponding histological sections. Furthermore, stereology-based morphometry was compared with morphometric semi-automated micro-CT analysis within the same micro-CT scan. Agreement of methods was assessed by regression and Bland-Altman analysis. Comparing histology with micro-CT, alveolar surface densities (35.4 +/- 2.4 vs. 33.4 +/- 1.9/mm, P < 0.05) showed a correlation (r = 0.72; P = 0.018) with an agreement of 2 +/- 1.6/mm; the mean linear intercept (135.7 +/- 14.5 vs. 135.8 +/- 15 microm) correlated well (r = 0.97; P < 0.0001) with an agreement of -0.1 +/- 3.4 microm. Semi-automated micro-CT analysis resulted in smaller alveolar surface densities (33.4 +/- 1.9 vs. 30.5 +/- 1/mm; P < 0.01) with a correlation (r = 0.70; P = 0.023) and agreement of 2.9 +/- 1.4/mm. Non-destructive micro-CT scanning offers the advantage to visualize the spatial tissue architecture of small lung samples two and three dimensionally.

The digestive tract of Nautilus pompilius (Cephalopoda, Tetrabranchiata): an X-ray analytical and computational tomography study on the living animal.

Using X-ray analytical studies and computational tomography, the position of the digestive tract of the tetrabranchiate cephalopod Nautilus pompilius L. was demonstrated in a living animal. For the first time, a detailed analysis of the rate of digestion and the duration of the different phases of a digestive cycle has been made using these in vivo methods. At 20 min after food intake, the food has entered the stomach, where it is reduced to small pieces; most is stored in the crop, which is enlarged to approximately four times its original size. The chyme reaches the midgut gland 3 h and the rectal loop 5 h after food intake. The time between food intake and elimination is 12 h. Thus, in Nautilus pompilius, digestion takes approximately the same time as described for nectobenthic sepioids and benthic octopods but is approximately 6 h longer than in loliginids, which have a pelagic mode of life. Furthermore, the three-dimensional structure of the digestive tract of a living Nautilus pompilius L. was demonstrated using computational tomography.