Objective:To investigate the magnetic resonance imaging (MRI) features of desmoplastic small round cell tumor (DSRCT) of the abdomen and pelvis.Method:The retrospec-tive and descriptive study was conducted. The clinicopathological data of 8 patients with DSRCT of the abdomen and pelvis, including 3 cases admitted in Yueqing People's Hospital and 5 cases admitted in Wenzhou People's Hospital, from January 2008 to June 2022 were collected. There were 5 males and 3 females, aged (43±5)years. All patients underwent MRI plain and enhanced scanning. Observa-tion indicators: (1) imaging features of DSRCT of the abdomen and pelvis; (2) treatment and pathological examination characteristics of DSRCT of the abdomen and pelvis; (3) follow-up. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distri-bution were represented as M(range). Count data were described as absolute numbers. Results:(1) Imaging features of DSRCT of the abdomen and pelvis. ① Tumor location. Of the 8 patients, there were 6 cases with tumors located respectively at the lower edge of the liver in the right quarter costal region, the medial side of the ileocecal region in the right iliac region, the medial side of the caecum in the right iliac region, the gastro-pancreatic space in the left quarter costal region, the mesenteric space in the left iliac region and the right side of pelvic bladder, and 2 cases with tumors located at retroperitoneal space of left quarter rib region. ② Tumor size. There were 13 lesions in the 8 patients, and the maximum diameter of tumor was 9.1 (range, 3.5?20.0)cm. Of the 8 patients, there were 5 cases with single tumor and 3 cases with multiple tumors. ③ Tumor shape and boundary. Of the 8 patients, there were 4 cases with tumor in expansive growth and 4 cases with tumor in invasive growth. There were 5 cases with tumor of intratumoral necrosis and cystic degene-ration, 4 cases with tumor of intratumoral hemorrhage, 4 cases with tumor of intratumoral spot calcification, 3 cases with tumor of peritumoral tissue exudation. One patient may combined with multiple imaging manifestations. ④ Imaging characteristics of MRI plain scanning. Of the 8 patients, there were 4 cases with tumor of homogeneous hypointensity signal and 4 cases with tumor of hypointensity mixed with speckled hyperintensity (with hemorrhage) in T1 weighted imaging of MRI plain scanning. There were 3 cases with tumor of homogeneous hyperintensity and 5 cases with tumor of high signal at the edge, patchy and spot-shaped in the center in T2 weighted imaging of MRI plain scanning. There were 5 cases with tumor of high, equal and low confounding signals and 3 cases with tumor of high and low signals in T2 weighted imaging fat suppression sequence of MRI plain scanning. There were 3 cases with tumor of uniform high signals and 5 cases with tumor of high, equal and low mixed signals in diffusion weighted imaging of MRI plain scanning. ⑤ Imaging characteristics of MRI enhanced scanning. All 8 patients had tumor of heterogeneous enhancement in MRI enhanced scanning, including 2 cases with significant enhancement in arterial phase, continuous enhancement in portal phase, slightly reduced enhancement in delayed phase, 4 cases with moderate enhancement in arterial phase, continuous enhancement in portal phase, slowly exited enhancement in delayed phase, 2 cases with mild enhancement in arterial phase, continuous enhancement in portal phase, slowly exited enhancement in delayed phase. Of the 8 patients, there were 3 cases with tumor of annular enhancement with intratumoral strip or grid signals and 3 cases with tumor of peritumoral blood vessels increased and thickened signals. ⑥ Tumor invasion and metastasis. Of the 8 patients, there were 4 cases with tumor invaded bowel, 2 cases with tumor invaded surrounding tissues, 1 case with tumor invaded left kidney, spleen and pancreatic tail, 1 case with tumor invaded distal of left ureter. There were 5 cases with abdominal, retroperitoneal and inguinal lymph nodes enlargement, 4 cases with multiple nodular thickening of peritoneum and ascites, 2 cases with tumor liver and lung metastasis and 1 case with tumor rib, femur and sacrum metastasis. One patient may combined with multiple tumor metastasis. (2) Treatment and patholo-gical examination characteristics of DSRCT of the abdomen and pelvis. Of the 8 patients, 3 patients underwent complete resection as clear tumor boundary, 3 patients underwent tumor partial resection as tight adhesion between tumor and surrounding blood vessels, 2 cases underwent tumor tissue pathological examination as extensive metastasis of peritoneum, omentum, mesentery and surrounding intestine. All 8 patients were diagnosed as DSRCT by microscopic examination, electron microscopic examination, immunohistochemical staining and cytogenetic examination. (3) Follow-up. All 8 patients underwent postoperative follow-up and died during the follow-up.Conclusion:MRI features of abdominal and pelvic DSRCT include single or multiple lobulated masses with unclear boundaries, invading the omentum, mesentery, peritoneum and adjacent tissues in most cases, mixed signals and heterogeneous mild to moderate enhancement in enhanced scanning.

Objective:To establish a method for the rapid determination of the three metabolites of xylene, 2-methylmarmaluronic acid, 3-methylmarmaluronic acid and 4-methylmarmaluronic acid, in urine of occupationally exposed workers by ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) .Methods:In July 2022, urine samples were diluted and extracted with pH=6.86 phosphate cache solution, cleaned up by a MAX solid-phase extraction (SPE) column and separated by an Accucore Ph/Hexyl column (100 mm×2.1 mm, 2.6 μm) with a gradient of 5 mmol/L ammonium formate-0.1% formic acid aqueous solution and methanol as mobile phases. The analysis was carried out in electrospray ionization mode and full mass-data dependent secondary mass spectrometry mode, and quantified by external standard method. The characteristics of each index of this method were analyzed.Results:A good linearity was obtained in the concentration range of 1.0-200.0 μg/L for 2-methylmuramic acid, 3-methylmuramic acid and 4-methylmuramic acid with the correlation coefficients of 0.9979-0.9993. The limits of detection of the method were 0.18-0.24 μg/L. While the spiked recoveries at the three concentrations (1.0 μg/L, 100.0 μg/L, and 180.0 μg/L) were in the range of 83.0%-93.7%, with the relative standard deviations of 2.2%-7.9%.Conclusion:The UPLC-HRMS method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the three metabolites of xylene in the urine of occupationally exposed workers.

Objective:To evaluate the influence of the sleeve lengths and implant lengths on accuracy of static computer-assisted implant surgery (sCAIS).Methods:Twenty-eight models of bilateral mandibular single tooth loss were included. Fifty-five implants were placed under the guidance of sCAIS (Straumann Bone Level 4.1 mm×10 mm). According to the height of metal sleeve of static guide plate, 55 implants were divided into 11 groups (free hand group, 1 mm group, 2 mm group, 3 mm group, 4 mm group, 5 mm group, 6 mm group, 7 mm group, 8 mm group, 9 mm group, 10 mm group), with 5 implants in each group. Eight research models were included. Group with 5 mm sleeve guides were used to place implants of different length, (Straumann Bone Level width 4.1 mm, height was 8 mm, 10 mm and 14 mm), 5 implants in each group. Eighteen patients with mandibular single tooth loss were included in the Department of Oral Implantology, Tianjin Stomatological Hospital from October 2018 to June 2019. There were 10 males and 8 females, 18-46(33.7±7.9) years old. A total of 18 implants were implanted and divided into 3 groups (free hand group, 3 mm group and 5 mm group) with 6 implants in each group. Digital software was used to compare the implant positions before and after implantation. Non-parametric Kruskal-Wallis test or one-way ANOVA were used to analyze the results.Results:There was no significant difference in implant vertical deviation between different sleeve height groups (1-10 mm) and free hand group, but the neck deviation in free hand group[(1.04±0.13) mm] was significantly higher than that in different sleeve height groups (1-10 mm) ( P<0.05). The tip deviations of free hand group, 1 mm group and 2 mm group [(1.32±0.43), (0.83±0.10) and (0.78±0.11) mm, respectively] was significantly higher than that of 10 mm group [(0.31±0.14) mm]( P<0.05). The angle deviation of free hand group and 1 mm group (3.99°±0.85° and 2.59°±0.69°), respectively] was significantly higher than that of 10 mm group (0.61°±0.03°) ( P<0.05). The tip deviations of implants in the 14 mm group [(0.83±0.22) mm] was significantly higher than that in the 8 mm and 10 mm groups [(0.44±0.07) and (0.49±0.06) mm, respectively]. Clinical studies showed that there was no significant difference in neck deviation, tip deviation and angle deviation between 3 mm group and 5 mm group ( P>0.05), but deviations were significantly lower than those in free hand group ( P<0.05). Conclusions:The length of the sleeves has significant influence on the accuracy of the surgical guide. There was no significant difference in accuracy of the implant guide with 3 mm or 5 mm metal sleeves. The vitro study has some limitations and needs further systematic research.

Objective:To establish a method for the rapid determination of the three metabolites of xylene, 2-methylmarmaluronic acid, 3-methylmarmaluronic acid and 4-methylmarmaluronic acid, in urine of occupationally exposed workers by ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) .Methods:In July 2022, urine samples were diluted and extracted with pH=6.86 phosphate cache solution, cleaned up by a MAX solid-phase extraction (SPE) column and separated by an Accucore Ph/Hexyl column (100 mm×2.1 mm, 2.6 μm) with a gradient of 5 mmol/L ammonium formate-0.1% formic acid aqueous solution and methanol as mobile phases. The analysis was carried out in electrospray ionization mode and full mass-data dependent secondary mass spectrometry mode, and quantified by external standard method. The characteristics of each index of this method were analyzed.Results:A good linearity was obtained in the concentration range of 1.0-200.0 μg/L for 2-methylmuramic acid, 3-methylmuramic acid and 4-methylmuramic acid with the correlation coefficients of 0.9979-0.9993. The limits of detection of the method were 0.18-0.24 μg/L. While the spiked recoveries at the three concentrations (1.0 μg/L, 100.0 μg/L, and 180.0 μg/L) were in the range of 83.0%-93.7%, with the relative standard deviations of 2.2%-7.9%.Conclusion:The UPLC-HRMS method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the three metabolites of xylene in the urine of occupationally exposed workers.

Objective To compare the radiation dose of in vitro pre-fenestration and in situ fenestration thoracic endovascular aortic repair(TEVAR)in treatment of aortic disease.Methods Data of 51 patients with aortic diseases who received in vitro pre-fenestration(group A)and 21 cases who underwent in situ fenestration(group B)TEVAR were retrospectively analyzed.The fluoroscopy duration,total reference air kerma(AK),total dose area product(DAP)and TEVAR time were compared between groups.Results TEVAR was successfully completed in all 72 patients.Fluoroscopy duration([21.42±8.04]min vs.[34.57±9.07]min)and total DAP(44315.0[31157.0,56307.5]μGy·m2 vs.72153.0[45460.0,82354.0]μGy·m2)in group A were both significantly lower than those in group B(both P＜0.05),while total AK(2423[1638,3533]mGy vs.3600[1898,3921]mGy)and TEVAR time([83.41±22.89]min vs.[81.00±22.13]min)in group A were not significant different from those in group B(both P＞0.05).Conclusion Compared with in situ fenestration TEVAR,both the fluoroscopy time and total DAP of in vitro pre-fenestration TEVAR significantly reduced for treating aortic diseases.