Comparison between abdominal ultrasound and nuclear magnetic resonance imaging detection of placenta accreta in the second and third trimester of pregnancy.

This study is to determine accuracy of abdominal ultrasound and nuclear magnetic resonance imaging (MRI) for placenta accreta in the second and third trimester of pregnancy and to define the most relevant features of abdominal ultrasound and MRI for placenta accreta prediction.Between September 2012 and September 2018, 245 high risk of placenta accreta in the second trimester of pregnancy were prenatal diagnosed by abdominal ultrasound and MRI and they were followed up until the end of pregnancy.Forty-six patients at the second trimester of pregnancy and 40 patients at the third trimester of pregnancy were confirmed as placenta accreta. For the second and third trimester of pregnancy, the sensitivity (Se), specificity (Sp), positive and negative predictive value (PPV and NPV) of abdominal ultrasound were 95.65% versus 97.50%, 91.78% versus 90.70%, 88% versus 83%, and 97% versus 99%, respectively, while the Se, Sp, PPV, and NPV of MRI were 89.13% versus 92.50%, 87.67% versus 8721%, 82% versus 77%, and 93% versus 96%, respectively. Five features having significant statistical differences between normal placentation women and placenta accreta patients in second or third trimester of pregnancy, including loss of the normal retroplacental clear space, thinning or disappearance of the myometrium, increased vascularization at the uterine serosa-bladder wall interface, and vascularization perpendicular to the uterine wall on abdominal ultrasound, and uterine bulging and dark intraplacental bands on MRI.Abdominal ultrasound and MRI for placenta accreta in the second and third trimester of pregnancy could provide meaningful imaging evidences.

[Effects of levonorgestrel intrauterine system on endometrial tissue after endometrial polyps resection by hysteroscopy].

OBJECTIVE: To explore the changes of endometrial tissues after the insertion of levonorgestrel intrauterine system (LNG-IUS). METHODS: The endometrial tissues were harvested from 21 cases after endometrial polyps resection by hysteroscopy. And the patients received a 1-year follow-up. The immunohistochemical stains for estrogen receptor (ER), progesterone receptor (PR), Ki-67, bcl-2 and bax were used for semi-quantitative analyses. The changes of endometrial thickness were monitored and uterine weight was observed with a 3-year follow-up. RESULTS: The endometrial thickness and uterine weight declined continuously after the insertion of LNG-IUS. The endometrial thickness decreased from the preoperative level of (9.8 ± 1.2) mm to (3.5 ± 1.0) mm while the uterine weight dropped from the preoperative level of (98.8 ± 8.6) g to (66.6 ± 9.8) g. The expressions of ER, PR and Ki-67 were significantly lower than those of the para-polyps endometrial tissue (P < 0.05). The expressions of bcl-2 and bax were significantly higher than those of the para-polyps endometrial tissue (P < 0.05). CONCLUSION: LNG-IUS may prevent the recurrence of uterine endometrial polyps through its inhibited expressions of ER, PR and Ki-67 and induced endometrial apoptosis.

[Near infrared spectroscopy system structure with MOEMS scanning mirror array].

A method which uses MOEMS mirror array optical structure to reduce the high cost of infrared spectrometer is given in the present paper. This method resolved the problem that MOEMS mirror array can not be used in simple infrared spectrometer because the problem of imaging irregularity in infrared spectroscopy and a new structure for spectral imaging was designed. According to the requirements of imaging spot, this method used optical design software ZEMAX and standard-specific aberrations of the optimization algorithm, designed and optimized the optical structure. It works from 900 to 1 400 nm. The results of design analysis showed that with the light source slit width of 50 microm, the spectrophotometric system is superior to the theoretical resolution of 6 nm, and the size of the available spot is 0.042 mm x 0.08 mm. Verification examples show that the design meets the requirements of the imaging regularity, and can be used for MOEMS mirror reflectance scan. And it was also verified that the use of a new MOEMS mirror array spectrometer model is feasible. Finally, analyze the relationship between the location of the detector and the maximum deflection angle of micro-mirror was analyzed.