L4–L5 traumatic spondylolisthesis has been rarely reported in the literature. At lumbar spine level traumatic dislocation lesion realizes“traumatic spondylolisthesis or traumatic bilateral lumbar facet locked syndr...L4–L5 traumatic spondylolisthesis has been rarely reported in the literature. At lumbar spine level traumatic dislocation lesion realizes“traumatic spondylolisthesis or traumatic bilateral lumbar facet locked syndrome”. The aim of the present paper is to report this rare lesion and discuss its mechanism and management. A case report is followed by Literature review made on Medline and scholar google database from 2000 to 2015. The case report concerned a 33-year-old man, who refused to wear a seat belt, injured his lumbar spine following a motor vehicle accident. L4-L5 spondylolisthesis occurred after the vehicle rolled over several times. Sixteen months after the accident the patient had a favorable outcome. Literature review on Medline and scholar google database from 2000 to 2015 was carried out and five cases of traumatic spondylolisthesis were found. The Sex ratio was 3/2. Surgical treatment consisted of posterolateral interbody fusion. Traumatic lumbar spine spondylolisthesis is rare. When it occurs, it is always associated with vertebral lumbar fracture. L4-L5 traumatic spondylolisthesis was caused by a high-energy mechanism and improper use of seat belt.展开更多
This study evaluates the long-term radiometric performance of the USGS new released Landsat Collection 1 archive, including the absolute calibration of each Landsat sensor as well as the relative cross-calibration amo...This study evaluates the long-term radiometric performance of the USGS new released Landsat Collection 1 archive, including the absolute calibration of each Landsat sensor as well as the relative cross-calibration among the four most popular Landsat sensors. A total of 920 Landsat Collection 1 scenes were evaluated against the corresponding Pre-Collection images over a Pseudo-Invariant Site, Railroad Valley Playa Nevada, United States (RVPN). The radiometric performance of the six Landsat solar reflective bands, in terms of both Digital Numbers (DNs) and at-sensor Top of Atmosphere (TOA) reflectance, on the sensor cross-calibration was examined. Results show that absolute radiometric calibration at DNs level was applied to the Landsat-4 and -5 TM (L4 TM and L5 TM) by –1.119% to 0.126%. For L4 TM and L5 TM, the cross-calibration decreased the radiometric measurement level by rescaling at-sensor radiance to DN values. The radiometric changes, –0.77% for L4 TM, 0.95% for L5 TM, –0.26% for L7 ETM+, and –0.01% for L8 OLI, were detected during the cross-calibration stage of converting DNs into TOA reflectance. This study has also indicated that the long-term radiometric performance for the Landsat Collection 1 archive is promising. Supports of these conclusions were demonstrated through the time-series analysis based on the Landsat Collection 1 image stack. Nevertheless, the radiometric changes across the four Landsat sensors raised concerns of the previous Landsat Pre-Collection based results. We suggest that Landsat users should pay attention to differences in results from Pre-Collection and Collection 1 time-series data sets.展开更多
文摘L4–L5 traumatic spondylolisthesis has been rarely reported in the literature. At lumbar spine level traumatic dislocation lesion realizes“traumatic spondylolisthesis or traumatic bilateral lumbar facet locked syndrome”. The aim of the present paper is to report this rare lesion and discuss its mechanism and management. A case report is followed by Literature review made on Medline and scholar google database from 2000 to 2015. The case report concerned a 33-year-old man, who refused to wear a seat belt, injured his lumbar spine following a motor vehicle accident. L4-L5 spondylolisthesis occurred after the vehicle rolled over several times. Sixteen months after the accident the patient had a favorable outcome. Literature review on Medline and scholar google database from 2000 to 2015 was carried out and five cases of traumatic spondylolisthesis were found. The Sex ratio was 3/2. Surgical treatment consisted of posterolateral interbody fusion. Traumatic lumbar spine spondylolisthesis is rare. When it occurs, it is always associated with vertebral lumbar fracture. L4-L5 traumatic spondylolisthesis was caused by a high-energy mechanism and improper use of seat belt.
文摘This study evaluates the long-term radiometric performance of the USGS new released Landsat Collection 1 archive, including the absolute calibration of each Landsat sensor as well as the relative cross-calibration among the four most popular Landsat sensors. A total of 920 Landsat Collection 1 scenes were evaluated against the corresponding Pre-Collection images over a Pseudo-Invariant Site, Railroad Valley Playa Nevada, United States (RVPN). The radiometric performance of the six Landsat solar reflective bands, in terms of both Digital Numbers (DNs) and at-sensor Top of Atmosphere (TOA) reflectance, on the sensor cross-calibration was examined. Results show that absolute radiometric calibration at DNs level was applied to the Landsat-4 and -5 TM (L4 TM and L5 TM) by –1.119% to 0.126%. For L4 TM and L5 TM, the cross-calibration decreased the radiometric measurement level by rescaling at-sensor radiance to DN values. The radiometric changes, –0.77% for L4 TM, 0.95% for L5 TM, –0.26% for L7 ETM+, and –0.01% for L8 OLI, were detected during the cross-calibration stage of converting DNs into TOA reflectance. This study has also indicated that the long-term radiometric performance for the Landsat Collection 1 archive is promising. Supports of these conclusions were demonstrated through the time-series analysis based on the Landsat Collection 1 image stack. Nevertheless, the radiometric changes across the four Landsat sensors raised concerns of the previous Landsat Pre-Collection based results. We suggest that Landsat users should pay attention to differences in results from Pre-Collection and Collection 1 time-series data sets.
