Objective:To construct core medical skill index system for helicopter medical rescue personnel by Delphi expert consensus method.Methods:This study combined literature review and two rounds of Delphi expert correspondence to construct the core skill index system. Total of 22 experts from relevant disciplines were selected purposively to conduct Delphi expert consultation.Results:The effective questionnaire recovery rates of the two rounds of Delphi expert correspondence was 100%; the authority coefficient of experts was 0.87; the Kendall coordination coefficients of the importance of the first and second level indexes were 0.380 and 0.338 in the first round of correspondence, and then 0.415 and 0.357 in the second round. the Kendall coordination coefficients of the feasibility of the second level indexes were 0.347 in the first round of correspondence and 0.354 in the second round. The final core skill index system for helicopter medical rescue personnel includes 4 primary indicators: core medical skill for diseases or trauma in respiratory system, circulatory system, sports system and other system, and 32 secondary indicators.Conclusions:The core medical skill index system for helicopter medical rescue personnel constructed through two rounds of Delphi expert correspondence is scientific and reasonable, which can provide a scientific basis to accurately understand, describe, analyze, and evaluate the competence level of helicopter medical rescue personnel, as well as serve as a content framework for training programs.

Objective To explore the predictive value of slow apparent diffusion coefficient(ADCslow),fast apparent diffusion coefficient(ADCfast)and perfusion fraction(f)value of intravoxel incoherent motion in body diffusion-weighted imaging(IVIM-DWI)sequence in early lumbar disc degeneration in young people.Methods The IVIM-DWI technique was used as quantitative magnetic resonance imaging for 120 patients(596 lumbar intervertebral discs)with lower back pain included in Wenzhou People's Hospital.The ADCslow,ADCfast and f values of all lumbar intervertebral discs were measured,and then they were divided into 3 groups according to the Pfirrmann grading standard.SPSS 20.0 statistical software was used to analyze the data.Results The ADCfast value has statistical significance in distinguishing the lumbar intervertebral discs of each group:The area under the curve(AUC)of the normal group vs.the early degenerative group was 0.766,with a sensitivity of 64.2%and a specificity of 78.5%;The AUC of the normal group vs.the mid to late stage degenerative group was 0.822,with a sensitivity of 67.9%and a specificity of 91.3%;The AUC of the early degeneration group vs.the middle and late stage degeneration group was 0.797,with a sensitivity of 62.1%and a specificity of 92.1%.The ADCslow value has statistical significance in distinguishing the lumbar intervertebral discs of each group:AUC=0.707 in the normal group vs.the early degenerative group,with a sensitivity of 83.6%and a specificity of 61.0%;The AUC of the normal group vs.the mid to late stage degenerative group was 0.701,with a sensitivity of 84.5%and a specificity of 58.6%;The AUC of the early degeneration group vs.the middle and late stage degeneration group was 0.668,with a sensitivity of 86.6%and a specificity of 51.0%.The f value cannot distinguish between different groups of lumbar intervertebral discs.Conclusion ADCslow and ADCfast of IVIM-DWI sequence have certain accuracy and specificity in distinguishing the early degeneration of lumbar intervertebral disc in young people,which provides a reliable basis for early clinical treatment.

Objective:To investigate the characteristics of computed tomography(CT) and magnetic resonance imaging(MRI)of focal peliosis hepatis (PH).Methods:From January 1, 2015 to December 31, 2022, a total of 8 PH patients (10 lesions) diagnosed pathologically in Yueqing People′s Hospital were collected. The location, size, and shape of the lesions, as well as the CT (4 patients with 4 lesions) and MRI (5 patients with 7 lesions) characteristics of the patients were analyzed. Descriptive method was used for statistical analysis.Results:Among the 8 PH patients, 6 patients had lesions located in the right lobe of the liver, 1 in the left lobe of the liver, and 1 (3 lesions) in both left and right lobes of the liver. Eight lesions were round or round-like, and 2 lesions were irregularly shaped. The median maximum diameter of the lesions was 4.2 cm (ranged from 2.2 to 9.3 cm), of which the maximum diameters of 2 lesions were less than 3.0 cm, those of 6 lesions were 3.1 to 5.0 cm, and those of 2 lesions were more than 6.0 cm. Nine lesions had clear boundaries, and 1 lesion had blurred boundary; 9 lesions had capsule, 1 lesion had no capsule; 1 lesion had blood vessels passing through it. The CT plain scan of 4 patients (4 lesions) showed that 3 lesions had uniform density and 3 lesions had low density, the CT enhancement showed that 2 lesions were significantly enhanced in the arterial phase, 3 lesions were sustained moderately enhanced in the portal phase, and 2 lesions were sustained mildly enhanced in the delayed phase. The MRI plain scan of 5 patients (7 lesions) showed uniform signals in 6 lesions, low signal in 3 lesions and equal signal in 4 lesions on T1-weighted images, high signal in 6 lesions on T2-weighted images, high signal in 3 lesions and equal signal in 4 lesions on diffusion-weighted images. The MRI enhancement showed that 4 lesions were significantly enhanced in the arterial phase, 5 lesions were sustained moderately enhanced in the portal phase, and 6 lesions showed sustained mild enhanced in the delayed phase.Conclusion:The PH lesions are round or round-like, with clear or unclear boundaries and uniform or uneven density, and are characterised by low density on CT and MRI plain scan, low signal on T1-weighted images, and high signal on T2-weighted images and diffusion-weighted images, and moderate or significant sustained enhancement on CT and MRI enhancement.

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 explore the CT features of inflammatory pseudotumor like follicular dendritic cell sarcoma (FDCS) of the spleen.Methods:The clinical data of 12 patients with splenic inflammatory pseudotumor like FDCS admitted to 3 central hospitals including Yongjia People's Hospital in Zhejiang Province from January 2015 to December 2022 were retrospectively analyzed, including 4 males and 8 females, with a median age of 60 years old. The number, shape, size and CT features of the lesions were analyzed based on patient's CT image data.Results:CT scans of 12 patients showed 15 lesions, including 10 single lesions and 2 multiple lesions. The lesions were circular in 5 cases, elliptical in 4 cases, and irregular in 3 cases. The median maximum diameter of the mass is 6.5 cm. On plain scan, all 12 tumors showed low density or slightly low density. The CT value is (41.3±7.2) HU; 8 cases had uneven density and 4 cases had uniform density. There were 8 cases with clear tumor boundaries and 4 cases with unclear boundaries. There were 8 cases with tumor necrosis and cystic transformation, and 5 cases showed patchy bleeding lesions in the center of the tumor. Enhancement: the arterial phase shows small patches or flocculent enhancement at the edges or parenchymal parts of the tumor, with CT value of (56.0±3.8) HU. Among them, there were 7 cases of mild enhancement, 4 cases of moderate enhancement, and 1 case of significant enhancement. During the portal phase, there was mild to moderate persistent small patchy uneven enhancement, with CT value of (62.0±4.3) HU. Among them, there were 8 cases of mild enhancement and 4 cases of moderate enhancement. The delayed phase showed a slow withdrawal of enhancement, with CT value of (45.0±8.2) HU. All 12 cases underwent complete resection and were diagnosed with FDCS through pathological examination.Conclusion:FDCS plain scan shows circular or elliptical uneven low-density masses, with small patches or flocculent light to moderate uneven enhancement in the arterial phase, continuous enhancement in the portal phase, and slow withdrawal in the delayed phase as the main characteristics.

Mycolic acids (MAs), i.e. 2-alkyl, 3-hydroxy long-chain fatty acids, are the hallmark of the cell envelope of Mycobacterium tuberculosis and are related with antibiotic resistance and host immune escape. Nowadays, they've become hot target of new anti-tuberculosis drugs. There are two main methods to detect MAs, ¹⁴C metabolic labeling thin-layer chromatography (TLC) and liquid chromatograph mass spectrometer (LC-MS). However, the user qualification of ¹⁴C or the lack of standards for LC-MS hampered the easy use of this method. TLC is a common way to analyze chemical substance and can be used to analyze MAs. In this study, we used tetrabutylammonium hydroxide and methyl iodide to hydrolyze and formylate MAs from mycobacterium cell wall. Subsequently, we used diethyl ether to extract methyl mycolate. By this method, we can easily extract and analyze MA in regular biological labs. The results demonstrated that this method could be used to compare MAs of different mycobacterium in different growth phases, MAs of mycobacteria treated by anti-tuberculosis drugs or MAs of mycobacterium mutants. Therefore, we can use this method as an initial validation for the changes of MAs in researches such as new drug screening without using radioisotope or when the standards are not available.
Mycolic Acids/metabolism* ; Chromatography, Thin Layer ; Mycobacterium tuberculosis ; Fatty Acids ; Antitubercular Agents/pharmacology*

Objective:To investigate the computed tomography (CT) features of primary liver leiomyosarcoma (PHLMS).Methods:The retrospective and descriptive study was conducted. The clinical and imaging data of 10 patients with PHLMS who were admitted to 4 medical centers including 3 cases in Wenzhou Central Hospital, 3 cases in the Second Affiliated Hospital of Wenzhou Medical University, 2 cases in Wenzhou People's Hospital and 2 cases in Yueqing People's Hospital from January 2011 to December 2020 were collected. There were 5 males and 5 females, aged from 41 to 83 years, with a median age of 55 years. All 10 patients underwent abdominal CT examination. Observation indicators: (1) CT features; (2) treatment and pathological examination; (3) follow-up and survival. Follow-up using postoperative outpatient or inpatient examination to detect patient survival was conducted. Patients underwent imaging examination to detect tumor recurrence. Follow-up was up to December 2020. Measurement data with skewed distribution were represented as M (range). Count data were described as absolute numbers. Results:(1) CT features: results of CT examination showed that each of the 10 patients had only one single tumor, including 3 cases with tumor on the left lobe of liver and 7 cases with tumor on the right lobe of liver. The tumor diameter of the 10 patients was 8.0 cm(range, 4.5-13.5 cm). Results of plain CT scan of 10 patients showed that 7 cases had tumor in expansive growth as round or oval, with clear boundaries and the tumor parenchyma showing low-density signals and patchy lower density area can be seen in the center, and 3 cases had tumor in infiltrative growth as patchy, with unclear boundaries and the tumor parenchyma showing iso-density signals. The CT scan value of 10 patients was 40 HU(range, 23-47 HU). Results of enhanced CT scan at arterial phase of the 7 cases with tumor in expansive growth showed that 3 cases undergoing tumor parenchyma with uneven mild enhancement signals, 3 cases undergoing tumor parenchyma with uneven moderate enhancement signals and 1 case undergoing tumor parenchyma with uneven significant enhancement signal. The CT scan value of 7 cases was 68 HU(range, 62-88 HU). Results of enhanced CT scan at arterial phase of the 3 cases with tumor in infiltrative growth showed that the peripheral region had high signal than the central region. The CT scan value of 3 cases was 73 HU(range, 67-90 HU). Results of enhanced CT scan at portal vein phase in the 7 cases with tumor in expansive growth showed that the tumor parenchyma showing continuous and progressive mild and moderate enhancement with uneven density, and the CT scan value was 63 HU(range, 55-78 HU). Of the 7 cases, 3 cases showed the enhancement range of tumor parenchyma with the trend of fusion and filling, and 4 cases showed small patchy or nodular enhancement and grid like enhancement in the center and periphery of the tumor. Results of enhanced CT scan at portal vein phase in the 3 cases with tumor in infiltrative growth showed that the enhancement withdrew, the density was uneven, and the CT scan value was 58 HU(range, 50-62 HU). Results of enhanced CT scan at delayed phase in 10 patients showed that the enhancement in the tumor withdrew slowly, and the CT scan value was 53 HU(range, 50-60 HU). Of the 10 patients, 4 cases showed decreased density of enhanced nodules around the tumor and 6 cases showed partially fused and filled to the center of tumor with no enhancement in the necrotic part. (2) Treatment and pathological examination: all 10 patients underwent completed tumor resection successfully, and no metastasis was found in liver or the hilar region. Results of postoperative pathological examination showed that each of the 10 patients had only one single visible tumor with tumor diameter of 8.0 cm(range, 4.5?13.5 cm). Of the 10 patients, 7 cases had tumor with complete or incomplete pseudocapsule with clear boundary and 3 cases had tumor without pseudocapsule and the boundary was unclear. All 10 patients had tumor with hard parenchyma and the section was mostly gray and fish like. Among them, patchy or punctate necrosis was seen in 7 cases, small patchy or punctate hemorrhage was seen in 3 cases, and small patchy calcification was seen in 2 cases. Microscopically, the tumor tissue was crisscross, the tumor cells were in spindle shaped, the nuclei were in round, oval, blunt at both ends or in thin rod like, with obvious heteromorphism, large and deeply staining, and obviously division. Immunohistochemical staining showed positive staining of smooth muscle actin, desmin and vimentin. (3) Follow-up and survival: all 10 patients were followed up postoperatively for 6 to 130 months, with a median follow-up time of 55 months. The overall survival time of 10 patients were 10 to 120 months, with a median overall survival time of 46 months. Of the 10 patients, 2 cases died of tumor recurrence and distant metastasis 10 and 11 months after operation, respectively and 8 cases survived >12 months.Conclusions:Results of plain CT scan of PHLMS show clear or unclear cysts and solid masses with uneven density. Results of enhancement CT scan of PHLMS show persistent uneven enhancement in tumor parenchyma and the surrounding area.

Objective:To investigate the computed tomography (CT) features of gastric neuroendocrine neoplasm (GNEN).Methods:The retrospective and descriptive method was conducted. The clinicopathological data of 30 GNEN patients who were admitted to two domestic medical centers (13 cases in Wenzhou Hospital of Traditional Chinese Medicine and 17 cases in Wenzhou People′s Hospital) from January 2010 to December 2018 were collected. There were 23 males and 7 females, aged (62±4)years, with a range from 27 to 78 years. The patients underwent abdominal CT plain scan and dynamic enhancement scan. Two associate chief radiologists with more than 20 years of work experience observed and analyzed all the images respectively. Observation indicators: (1) CT examination; (2) treatment and postoperative pathological examination; (3) follow-up. Follow-up was conducted using outpatient examination and telephone interview to detect the survival of patients up to December 2018. Measurement data with normal distribution were represented as Mean± SD. Measurement data with skewed distribution were described as M (range). Results:(1) CT examination: of the 30 patients, 14 had the tumor located in the fundus of stomach, 10 had the the tumor located in the body of stomach, and 6 had the tumor located in the antrum. The tumor was elliptical in 18 cases and irregular in 12 cases. There were 15 cases of endogenous type, 13 cases of exogenous type, and 2 cases of intramural type. Patients with G1 neuroendocrine tumor had the maximum diameter of (6.8±1.6)cm, of which 4 cases had the maximum diameter less than 5.0 cm and 4 cases had the maximum diameter of 5.0 to 10.0 cm. Patients with G2 neuroendocrine tumor had the maximum diameter of (8.3±2.7)cm, of which 1 case had the maximum diameter less than 5.0 cm, 4 cases had the maximum diameter of 5.0 to 10.0 cm, and 2 cases had the maximum diameter greater than 10.0 cm. Patients with G3 neuroendocrine carcinoma had the maximum diameter of (17.8±2.2)cm, of which 6 cases had the maximum diameter of 5.0 to 10.0 cm and 9 cases had the maximum diameter more than 10.0 cm. The tumor showed swelling growth in 14 cases and invasive growth in 16 cases. The tumor boundary was clear in 14 cases and unclear in 16 cases. CT plain scan showed homogeneous tumor density in 10 cases and heterogeneous density in 20 cases. Nine patients had iso-density in the tumor parenchymal part, and the CT value was (34.0±3.5)HU. In the 18 cases of low density, the CT value was (16.6±1.4)HU. In the 3 cases of high density, the CT value was (45.3±3.6)HU. Of the 30 patients, 21 cases had small punctate or small round necrotic cyst lesions in the tumor, 10 cases had mesenteric lymph node, peritoneum, liver metastasis and adjacent omentum invasion; 17 cases had abdominal effusion. In the CT enhancement examination, 12 cases showed mild enhancement, and the CT value was (56.5±6.3)HU; 15 cases showed moderate enhancement, and the CT value was (66.0±5.4)HU; 3 cases showed significant enhancement, and the CT value was (76.6±5.8)HU. Seven cases showed homogeneous enhancement and 23 cases had heterogeneous enhancement. There were 8 cases with tortuous vessels. (2) Treatment and postoperative pathological examination: of the 30 patients, 10 cases with mesenteric lymph nodes, peritoneum, liver metastasis and adjacent omentum invasion underwent radical total gastrectomy; 14 cases without surrounding tissue invasion or metastasis underwent radical subtotal gastrectomy; 6 cases with tumor diameter less than 4.0 cm and without surrounding tissue invasion or metastasis underwent endoscopic resection. All the 30 patients were confirmed GNEN by postoperative pathological examination, including 8 cases of G1 neuroendocrine tumor, 7 cases of G2 neuroendocrine tumor, and 15 cases of G3 neuroendocrine carcinoma. Results of immunohistochemical staining showed that 30 patients were positive for synaptophysin, 23 were positive for chromogranin A, and 9 were positive for cytokeratin. (3) Follow-up: all the 30 patients were followed up for 10-80 months, with a median follow-up time of 39 months. The 5-year survival rate of 30 patients was 43.3% (13/30). The 5-year survival rates were 6/8, 3/7 and 4/15 of patients with G1 neuroendocrine tumor, G2 neuroendocrine carcinoma, and G3 neuroendocrine carcinoma.Conclusions:GNEN has the main manifestation as abdominal pain, with G3 as pathological classification, which is common in fundus and body of stomach. The CT findings of GNEN are characterized by swelling or infiltrating growth and round or irregular low-density masses. Tumors are prone to cystic transformation, and showed the mildly to moderately heterogeneous enhancement.

Objective:To analyze the CT and MRI features of primary hepatic sarcomatoid carcinoma.Methods:A retrospective study was conducted on 16 patients with primary hepatic sarcomatoid carcinoma who presented to Wenzhou People's Hospital of Zhejiang Province and the Second Affiliated Hospital of Wenzhou Medical University from January 2009 to June 2019. There were 8 males and 8 females, with age ranging from 35 to 71 years (average 56.8 years). The site, size, shape, margin, density of signal, adjacent tissue changes and degree enhancement of tumor were analyzed.Results:Tumors in the liver in the 16 patients were all solitary, with 11 in the right and 5 in the left liver. The maximum diameter of tumor ranged from 3 to 16cm (average 8.5cm). On plain CT scanning ( n=16), the tumors were round or oval in 6, and lobulated or irregular in 10 patients. The margins of the tumors were clear in 10 and unclear in 6 patients. All tumors showed low density, with 15 tumors showing uneven density, with necrosis and liquefaction of different sizes in the center, while 1 tumor showing uniform density. On plain MRI scanning ( n=4), four tumors had clear margins, with necrosis and liquefaction seen in the center of the tumors. The solid part showed a slightly lower signal on T 1 weighted imaging and a slightly higher signal on T 2 weighted imaging. The liquefaction focus of central necrosis showed higher signal intensity on T 2 weighted imaging. Enhanced scanning ( n=12 on CT enhancement and n=4 on MRI enhancement), the margins of the tumors were enhanced in the arterial phase. The enhancement was continued into the portal venous and delayed phases in 7 patients. Strip septate and margin enhancement in the tumor were enhanced in the arterial phase. The enhancement was continued into the portal venous and delayed phases in 7 patients. Inhomogeneous strengthening in the tumor was enhanced in the arterial phase. The enhancement was continued into the portal venous and delayed phases in 1 patient. Inhomogeneous strengthening in the tumor was enhanced in the arterial phase. The enhancement was continued into the portal venous phase. In the delayed phase, enhancement in the tumor decreased, but there was continuous enhancement of the margin and interval of the tumor in 1 patient. Conclusions:Hepatic sarcomatoid carcinoma showed dual imaging characteristics of sarcoma and cancer. The imaging features of hepatic sarcomatoid carcinoma depended on the proportion of sarcomatoid components. Large intrahepatic tumors showed necrotic cystic degeneration, moderate or significant persistent enhancement in striped septum and margin of tumor.

Objective: To investigate the CT and MRI features of adult rhabdomyosarcoma (RMS) of extremities. Methods: A retrospective analysis was carried out on CT and MRI findings of 10 patients with rhabdomyosarcoma of extremities confirmed by surgery and pathology in Wenzhou People′s Hospital and the Second Affiliated Hospital of Wenzhou Medical University. The site, size, shape, margin, density or signal, adjacent tissue changes and enhanced degree of the mass were observed. Results: In the 10 cases, the mass was located in the thigh in 6 cases, in the calf in 3 cases, and in the upper arm in 1 case. The maximum diameter of the tumor was 2.9-22.5 (12.0 ± 7.2) cm. The masses were oval in 2 cases and irregular in 8 cases. The margins of the masses were clear in 2 cases and unclear in 8 cases. There was invasive destruction of adjacent bone in 3 cases, intratumoral necrotic cystic changes in 8 cases, intratumoral hemorrhage in 2 case, and lymph node metastasis in 3 cases. Four patients underwent plain CT scan: CT presented isodensity in 1 case and slightly lower density in 3 cases. The mass density was uniform in 1 case and uneven in 3 cases. CT value of the solid part of the mass was 27-47 (42 ± 6) HU in average. Three patients underwent enhanced CT scan: all the enhanced masses showed uneven enhancement, including 1 case of mild enhancement and 2 cases of moderate enhancement, with no enhancement of necrotic cystic lesion area and clear in lesion boundary. Nine patients underwent plain MRI scan: mass of 9 cases presented iso-signal or slightly lower signal on T₁WI, including 4 cases with iso-signal and 5 cases with slightly lower signal. There were 7 cases of uneven signals and 2 cases of uniform signals. The mass presented high signal on T₂WI, including 8 cases with uneven signals and 1 case with uniform signals, and the necrotic cystic lesion showed higher signal on T₂WI. Seven patients underwent enhanced MRI scan: all the enhanced masses showed uneven enhancement, including significant enhancement in 5 cases, moderate enhancement in 2 cases, no enhancement in necrotic cystic lesion area, and "perivascular" phenomenon in 4 cases. Conclusions CT or MRI examination shows that the soft tissue tumor of the extremities presents low density on CT, equal or slightly low T₁WI signal on MRI, and high signal on T₂WI, with necrotic cystic lesion inside peripheral blood vessel density in the tumor, without calcification and significantly or moderately uneven enhancement should consider the possibility of RMS should be considered.