Low-Voltage, High-Pitch Computerized Tomography Angiography of the Infrarenal Aorta and Lower Extremity Vessels: Assessment of Radiation Dose, Image Quality With Hybrid Iterative Reconstruction, and Efficacy of Test Injection Using a Monitoring Scan at Knee Level.

OBJECTIVES: Our aim was to assess image quality and radiation dose of low-voltage high-pitch computed tomography angiography of the infrarenal aorta and lower extremities and evaluate the efficacy of test injection technique using a monitoring scan at knee level. METHODS: A total of 60 patients with suspected peripheral arterial disease were divided into 2 groups: group 1 (30 patients, 80 kVp, high pitch [3.2], and hybrid iterative reconstruction [sinogram-affirmed iterative reconstruction]) and group 2 (30 patients, 120 kVp, low pitch [1.0], and filtered back projection reconstruction). The test injection technique at knee level was used to determine the scan delay time in group 1. The image quality and radiation exposure were compared. RESULTS: There were significant differences between the 2 groups in mean (SD) arterial attenuation (80 vs 120 kVp: 507.78 [103.01] vs 317.54 [62.03] Hounsfield units, P < 0.001), mean (SD) signal-to-noise ratio (51.04 [20.29] vs 34.66 [9.94], P < 0.001), and contrast-to-noise ratio (44.83 [17.93] vs 28.26 [9.60], P < 0.001). No difference in subjective image quality was found between the 2 groups (all P > 0.05). The imaging time was significantly shorter in group 1 (2.70 [0.11] vs 14.65 [0.90s], P < 0.001). The mean (SD) effective dose was significantly lower in the 80 kVp group (0.76 [0.06] vs 4.29 [0.63] mSv, P < 0.001). CONCLUSIONS: The 80-kVp high-pitch computed tomography angiography of the lower limbs using sinogram-affirmed iterative reconstruction yields reduction of radiation exposure as well as obtains acceptable image quality if acquisition protocols are used in conjunction with the test injection technique using monitoring scan at knee level to determine the delay time.

The accuracy of sizing of the femoral component in total knee replacement.

PURPOSE: Femoral sizing in total knee replacement is important. Either undersizing or oversizing may result in deleterious effects to the clinical outcome after the surgery. There has been no study on the precision and accuracy of femoral sizing and the effect of measurement at different landmarks over the distal femur. This study assesses the intra-observer and inter-observer error of femoral sizing and identifies the effect of the placement site of the anterior referencing tool on femoral sizing. METHODS: Five investigators with different clinical experience measured the femoral size of 10 cadaveric specimens twice using three anterior referencing tool. The measurement of the femoral size was repeated at nine designated points on the anterior cortex of the cadaveric femora. RESULTS: Excellent intraobserver and interobserver agreements were obtained using the three anterior referencing tools. When the size on which the majority agreed was regarded as the actual size of the specimen, measurement at the nine designated points on the anterior cortex showed a deviation from the actual size from 6.2 to 46.2 %. Placing the femoral sizer stylus at the middle and 2 cm above the proximal margin of the anterior femoral condyle yielded the highest precision and accuracy. CONCLUSION: Regardless of the experience of the surgeons, measurement of the femoral size using the three anterior referencing tools is very accurate. Placing the stylus of the femoral sizer at the middle and 2 cm above the proximal margin of the anterior femoral condyle best reflects the actual size of the femur. LEVEL OF EVIDENCE: Experimental study.

Juvenile Hormone Is an Important Factor in Regulating Aspongopus chinensis Dallas Diapause.

Aspongopus chinensis is a Chinese traditional edible and medicinal insect, which is in great demand in the society. This insect reproduces once a year which is caused by reproductive diapause resulting in insufficient production in wild resources. However, the mechanism of diapause in A. chinensis is still unclear. In this study, we focus on the relationship between juvenile hormones (JHs) and A. chinensis diapause. The results showed that JHIII concentration in diapause adult individuals was significantly lower than that in diapause termination adult individuals. When exogenous JHⅢ was injected into diapause adults, the rate of mating was increased significantly, development of the reproductive systems was accelerated, consumption of fat intensified, the expression of juvenile hormone acid o-methyl-transferase (JHAMT) was upregulated, and juvenile hormone epoxide hydrolase (JHEH) and fatty acid synthase (FAS) gene expressions were downregulated. In addition, RNAi of JHAMT decreased JH concentration, delayed the development of reproductive systems, slowed down fat consumption, and delayed the mean mating occurrence time significantly. Conversely, RNAi of JHEH resulted in an increased concentration of JH, development of reproductive systems was accelerated, consumption of fat was intensified, and mean mating occurrence time advanced significantly. Taken together, these findings uncovered that JH plays an important role in regulating reproductive diapause in A. chinensis and, thus, could provide a theoretical basis for further research on the diapause of A. chinensis.