Objective:To assess the clinical and imaging features of SMARCB1-deficient sinonasal carcinoma.Methods:Form January 2016 to November 2021, the clinical data and pretreatment imaging findings of 16 cases with pathologically proven SMARCB1-de?cient sinonasal carcinomas were analyzed retrospectively in Beijing Tongren Hospital, Capital Medical University. Immunohistochemistry for SMARCB1 showed loss of the protein in the tumor nuclie. Clinical and imaging features, including tumor location, TNM stage, size, density of CT, bone change, MRI signal intensity, enhancement pattern, type of time-intensity curve (TIC) of dynamic contrast enhanced MRI (DCE-MRI), apparent diffusion coefficient (ADC) value and diffusion weighted imaging (DWI) were evaluated. For 14 cases, correlation of the ADC value and Ki-67 index was subsequently evaluated with Pearson correlation analysis.Results:For the 16 cases SMARCB1-deficient sinonasal carcinomas, clinical stage of T4 was 12 cases and T3 was 4 cases. The location included ethmoid sinus ( n=4), nasal cavity only ( n=1), both nasal cavity and ethmoid ( n=8), ethmoid and maxillary sinus ( n=1), ethmoid and frontal sinus ( n=1), ethmoid and sphenoid sinus ( n=1). The tumor size was (4.5±1.2) cm. Iso-attenuated of CT images was showed in 13 cases and heterogeneous with necrosis was showed in 3 cases. Focal bone erosion was found in 13 cases and extensive bone destruction was found in 3 cases. Compared with adjacent muscles, T 1WI of all 16 cases showed isointense, with focal hypointense in 3 cases. On T 2WI, the tumor was graded as isointense in 9 cases, hyperintense in 7 cases, with lower inner septal in 6 cases. Enhancement was graded as mild in 11 cases, moderate in 5 cases.MRI Enhancement images showed mild enhancement in 11 cases, moderate enhancement in 5 cases, heterogeneous enhancement in 6 cases, and homogeneous enhancement in 10 cases. For DCE-MRI of 14 cases, there were 10 cases of Ⅲ type and 4 cases of Ⅱ type of the TIC. The ADC value of 14 cases was (1.02±0.27)×10 -3 mm 2/s. The Ki-67 index was 48%±21%. No correlation was observed between Ki-67 index and ADC value ( r=-0.38, P=0.183). Conclusions:SMARCB1-deficient carcinomas are mostly centered in the nasal and ethmoid region of anatomic distribution. Tendency to be infiltrative the adjacent bone structure with invasive bone reaction, mild to moderate heterogeneous enhancement, T 2WI with lower inner septal, and Ⅲ types of TIC are certain suggestive imaging features of the entity.

目的 探讨酷似鼻咽癌的鼻咽-颅底骨髓炎(nasopharyngeal-skull base osteomyelitis,NP-SBO)的临床及影像学表现.方法 回顾性分析3例经病理证实的NP-SBO的临床特征、CT和MRI表现的特点.结果 2例患者患有糖尿病,2例C反应蛋白升高,1例白细胞升高.所有患者均于鼻咽顶后方右侧壁形成软组织肿块,其中1例累及鼻咽左侧壁;鼻咽黏膜线不完整1例,黏膜线完整2例.弥散加权成像(diffusion weighted imaging,DWI)与脑实质相比病变均呈略低信号,表观扩散系数(apparent diffusion coefficient,ADC)均呈略高信号.3例邻近颅底骨质破坏,均累及岩尖及斜坡.2例双侧咽后、颈Ⅱ区淋巴结肿大,淋巴结信号均匀,内部无囊变或坏死区.结论 表现为鼻咽软组织增厚及颅底骨质破坏的NP-SBO与晚期鼻咽癌影像表现非常相似,但有糖尿病史的老年患者,伴有炎症标记物升高、DWI无明显扩散受限,尤其是当鼻咽黏膜线清晰完整时,提示NP-SBO的诊断.

Objective:To investigate the effect of different scanning modes, detector width and location in detector on high and low contrast resolution of wide-detector CT image.Methods:The Catphan600 phantom with high and low contrast resolution modules was scanned with GE Revolution CT at the same CTDI vol. The scans were performed with the detector widths of 40, 80 and 160 mm for sequential scanning mode and with the detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 for spiral scanning mode. The resolution modules were placed at the adjacent region between two sequential scans, central and foot side edge in the longitudinal scanning range seperately. The subjective evaluation of the high and low contrast resolution was performed by two radiologists. Results:The high contrast resolution was 8 LP/cm at adjacent region between two sequential scans with the detector width of 80 mm or 160 mm in sequential scanning mode, and at the pitch of 0.5 in spiral scanning mode, while it was 7 LP/cm for the rest of detector combinations. The distinguishable diameter was 3 mm at 1% low contrast resolution at foot side edge with the detector widths of 80 mm or 160 mm in the sequential scanning mode, and it was 2 mm for all the other conditions. The distinguishable diameter was 2 mm at 1% low contrast resolution with the detector width of 40 mm and pitch 0.516 in the spiral scanning mode and it was worse with the wider detector and larger pitch.Conclusions:For the wide-detector CT, scanning mode, detector width, location in detector and pitches will affect the high and low contrast resolution to some degree. Appropriate selection should be done according to actual needs in clinical practice.

Objective:To compare the diagnostic value of three quantitative evaluation methods based on three-dimensional rapid fluid attenuation inversion recovery sequence (3D-FLAIR) vein-enhanced labyrinth images in endolymphatic hydrops.Methods:From October 2017 to April 2019, a retrospective study was conducted on 86 patients with unilateral otogenic vertigo who were admitted to Beijing Tongren Hospital, Capital Medical University. MRI was performed 8 h after the single-dose Gd-DTPA intravenously injection in all patients. Three evaluation methods were used to calculate the ratio of the endolymphatic area to the total lymphatic area, the ratio of the saccule to utricle area, and the ratio of the endolymphatic volume to the total lymphatic volume, respectively. The paired t test was used to compare the three ratios between the affected and healthy ears. With clinical diagnosis as the gold standard, the receiver operating characteristic (ROC) curve analysis was used to analyze the efficacy of three methods in diagnosing endolymphatic hydrops. Results:Totally 65 cases were finally diagnosed endolymphatic hydrops clinically. There were statistically significant differences of all the 3 ratios between the affected and healthy ears ( t=9.93, 7.22, 8.20, all P<0.001). The ROC curve showed that the area under the curve (AUC) of endolymph/total lymph area ratio, saccule/utricle area ratio, endolymph/total lymph volume ratio for diagnosis of endolymphatic hydrops were 0.882, 0.768, 0.884 (all P<0.001). And there were no significant differences between each paired AUCs (all P>0.05). Conclusions:All three methods of endolymph/total lymph area ratio, saccule/utricle area ratio, endolymph/total lymph volume ratio can quantitatively evaluate endolymphatic hydrops. The endolymphatic/total lymphatic area ratio method is still the most convenient method at present.

Objective:To assess the clinical and imaging features of NUT gene-related sinonasal carcinomas (NUT midline carcinome).Methods:The clinical data and pretreatment imaging findings of 5 cases with pathologically proven NUT sinonasal carcinomas were analyzed retrospectively in Beijing Tongren Hospital, Capital Medical University from January 2016 to December 2020. Of 5 cases, the tumors affected 4 females and 1 male with an age range of 15 to 48 years (median 19 years). Clinical data of all cases were available before surgery with both CT and MR examination. Tumor location, CT density, boney change, calcification, tumor size, T 1WI, T 2WI and diffusion weighted imaging (DWI) signal intensity, appearance diffusion coefficient (ADC), type of time intensity curve (TIC) of dynamic contrast-enhanced (DCE)-MRI were evaluated. Results:All five cases belonged to T4 stage of the clinic TNM system. The locations were nasal cavity ethmoid, sphenoid and maxillary sinus ( n=1), nasal and maxillary sinus ( n=1), nasal cavity and ethmoid sinus ( n=3). Iso-attenuated in 3 cases, heterogeneous with local necrosis in 2 cases, and heterogeneous with calcification in 3 cases on CT imaging. Bone erosion was found in 4 cases, and bone erosion with destruction in 1 case. The tumor sizes ranged from 4.2 to 4.9 cm (median 4.5 cm) on MR axial imaging. On T 1WI, 5 cases showed isointense compared with adjacent temporal muscles, with focal hypointense in 2 cases. On T 2WI, the tumor was graded as isointense in 3 cases, and hyperintense in 2 cases. Heterogeneous enhancement in all cases with mild in 3 cases, and moderate in 2 cases on postcontrast MR imaging. On DCE-MRI of 5 cases, there were 3 cases of type Ⅲ (washout-shaped curves), and 2 cases of type Ⅱ of the TIC (plateau-shaped curves). The range of ADC values was from 0.63×10 -3 to 1.17×10 -3 mm 2/s, and median ADC value was 0.84×10 -3 mm 2/s, of 5 cases with varying degrees of high signal on DWI. The Ki-67 index ranged from 30% to 80% of the tumor. An immunohistochemical study showed that the tumor cells of 5 cases were all positive for both NUT and INI-1 genes. One case was performed with biopsy and followed by chemotherapy, four cases were performed with surgery, combined with the following chemotherapy, and one also was implemented with radiation therapy. The follow-up time was 7-16 months. Five cases were all alive during the follow-up. Conclusions:The NUT midline sinonasal tract carcinoma is a rare, gene-related solid malignant tumor. The tumor is more commonly seen in young patients, mostly centered in the nasal and ethmoid region with invasive growth, more calcification on CT, and heterogeneous enhancement on MRI. These findings are some characteristics of the tumor.

Background With the global outbreak of coronavirus disease 2019 (COVID-19), chest computed tomography (CT) is vital for diagnosis and follow-up. The increasing contribution of CT to the population-collected dose has become a topic of interest. Radiation dose optimization for chest CT of COVID-19 patients is of importance in clinical practice. The present study aimed to investigate the factors affecting the detection of ground-glass nodules and exudative lesions in chest CT among COVID-19 patients and to find an appropriate combination of imaging parameters that optimize detection while effectively reducing the radiation dose. Methods The anthropomorphic thorax phantom, with 9 spherical nodules of different diameters and CT values of -800, -630, and 100 HU, was used to simulate the lesions of COVID-19 patients. Four custom-simulated lesions of porcine fat and ethanol were also scanned at 3 tube potentials (120, 100, and 80 kV) and corresponding milliampere-seconds (mAs) (ranging from 10 to 100). Separate scans were performed at pitches of 0.6, 0.8, 1.0, 1.15, and 1.49, and at collimations of 10, 20, 40, and 80 mm at 80 kV and 100 mAs. CT values and standard deviations of simulated nodules and lesions were measured, and radiation dose quantity (volume CT dose index; CTDIvol) was collected. Contrast-to-noise ratio (CNR) and figure of merit (FOM) were calculated. All images were subjectively evaluated by 2 radiologists to determine whether the nodules were detectable and if the overall image quality met diagnostic requirements. Results All simulated lesions, except -800 HU nodules, were detected at all scanning conditions. At a fixed voltage of 120 or 100 kV, with increasing mAs, image noise tended to decrease, and the CNR tended to increase (F=9.694 and P=0.033 for 120 kV; F=9.028 and P=0.034 for 100 kV). The FOM trend was the same as that of CNR (F=2.768 and P=0.174 for 120 kV; F=1.915 and P=0.255 for 100 kV). At 80 kV, the CNRs and FOMs had no significant change with increasing mAs (F=4.522 and P=0.114 for CNRs; F=1.212 and P=0.351 for FOMs). For the 4 nodules of -800 and -630 HU, CNRs had no statistical differences at each of the 5 pitches (F=0.673, P=0.476). The CNRs and FOMs at each of the 4 collimations had no statistical differences (F=2.509 and P=0.125 for CNRs; F=1.485 and P=0.309 for FOMs) for each nodule. CNRs and subjective evaluation scores increased with increasing parameter values for each imaging iteration. The CNRs of 4 -800 HU nodules in the qualified images at the thresholds of scanning parameters of 120 kV/20 mAs, 100 kV/40 mAs, and 80 kV/80 mAs, had statistical differences (P=0.038), but the FOMs had no statistical differences (P=0.085). Under the 3 threshold conditions, the CNRs and FOMs of the 4 nodules were highest at 100 kV and 40 mAs (1.6 mGy CTDIvol). Conclusions For chest CT among COVID-19 patients, it is recommended that 100 kV/40 mAs is used for average patients; the radiation dose can be reduced to 1.6 mGy with qualified images to detect ground-glass nodules and exudation lesions.

Objective::To survey and analyze the radiation doses of pediatric CT in some provinces (autonomous region) or municipalities in China, and compare them with the data released by the relevant domestic and international organizations, so as to identify the current status of Chinese pediatric CT radiation doses.Methods::Radiation doses of pediatric CT were collected during August and December 2016 from 40 hospitals (including 18 children’s hospitals) in 15 provinces, municipalities or autonomous regions across the China. The procedures of head CT, chest CT and abdomen CT were selected in these hospitals, and 10 patients in each group of 0- < 1 y, 1- < 5 y, 5- <10 y and 10- < 15 y were collected at random for every procedure. Weighted CT dose index (CTDI w), volumetric CT dose index (CTDI vol) and dose length product (DLP) were used as survey quantities. An independent sample Kruskal-Wallis rank sum test was performed for CTDI and DLP for each procedure for different age groups, and pairwise comparisons were performed for intra-group data. The same statistical method was also conducted for CTDI and DLP of the same procedure and age group in different provinces or municipalities. Results::The 75th percentiles of the distribution of CTDI and DLP in different age groups of 0- < 1 y, 1- < 5 y, 5- <10 y and 10- < 15 y were as follows: 36.5, 43.4, 49.1, 51.1 mGy and 488, 635, 723, 852 mGy.cm for head, 6.1, 6.4, 6.8, 9.6 mGy and 108, 136, 187, 293 mGy.cm for chest, 10.5, 10.3, 11.4, 13.0 mGy and 251,284,353, 523 mGy.cm for abdomen. The 50th percentiles of the distribution of the radiation doses for the same procedure varied with the ages (head, CTDI w: H = 155.66, DLP: H = 212.35, P < 0.05; chest, CTDI vol: H = 85.43, DLP: H = 197.36, P < 0.05; abdomen: H = 62.29, DLP: H = 173.22, P < 0.05)and with lower dose at lower age. Radiation doses were close for head between 5- <10 y and 10- <15 y groups, for chest between 1- <5 y and 5- <10 y groups and between 5- <10 y and 10- <15 y groups, and for abdomen between 0- <1 y and 1- <5 y groups, with no statistically significant difference (the adjusted P > 0.05). The dose levels of different provinces or municipalities in the same procedure and age group were not consistent, and the differences were statistically significant ( P < 0.05). The data were different from the domestic and international values of DRL. The 75th percentiles of CTDI w and DLP values of head CT were close to the data from Japan and UK(United Kingdom), higher than the data from Korea and EC(European Commission). The 75th percentiles of CTDI values of all age groups were lower than the values of Japan and UK, and larger than that of Korea and EC in chest CT and abdomen CT. Conclusions::The 75th percentile values of the distribution of the pediatric CT doses obtained from the survey were inconsistent with those released by the relevant national and international organizations. It is necessary to update the national DRLs for pediatric CT on the basis of the actual survey data.

Objective:To explore the clinical application value of each sequence by analyzing the characteristics of labyrinthine signal on MRI in patients with unilateral sudden deafness.Methods:Totally 52 patients of unilateral sudden deafness with inner ear MRI were analyzed retrospectively at Beijing Tongren Hospital, Capital Medical University from January 2016 to July 2019, all of which could find abnormalities in the labyrinth, including 17 cases of plain scan and 35 cases of enhanced scan, with sequences including plain T 1WI, enhanced T 1WI, plain and enhanced delayed 3D fluid attenuation inversion recovery (3D-FLAIR). The affected labyrinthine signal characteristics of each sequence were analyzed and the involvement sites were judged. The ability of each sequence to show labyrinthine abnormal signal was evaluated and scored. The Friedman test and Wilcoxon signed rank sum test were used to compare the subjective scores of the ability to show labyrinthine high signal in different sequences in plain and enhanced patients, respectively. Fisher′s exact probability method was used to analyze the relationship between the affected sites and the recovery of hearing, tinnitus and vertigo symptoms. Results:Fifty-two patients (100%, 52/52) showed labyrinthine high signal on T 1WI, 8 (15.4%, 8/52) showed higher signal and 3 (5.8%, 3/52) showed low signal on T 2WI. Thirty-five (100%, 35/35) showed high signal on enhanced T 1WI, among which 27 had enhancement (77.1%, 27/35). Fifty-two (100%, 52/52) showed significant high signal of the affected labyrinth on 3D-FLAIR (17 plain scan, 35 enhanced scan). The scores were 2 (2, 2), 3 (2, 3), 3 (3, 4) and 4 (4, 4) of T 1WI, enhanced T 1WI, plain and enhanced 3D-FLAIR respectively. The overall difference in subjective scores of plain T 1WI, enhanced T 1WI and enhanced 3D-FLAIR in enhanced patients was statistically significant (χ2=64.528, P<0.001), and the comparison between the two was statistically different (all corrected P<0.05). The plain 3D-FLAIR score was higher than the plain T 1WI in patients with a statistically significant difference ( Z=-3.729, P<0.001). Twenty-seven cases (51.9%, 27/52) exhibited high signal at the ampulla of semicircular canals, with a statistically significant difference in the distribution of hearing recovery or not ( P=0.001). Conclusions:Both T 1WI and 3D-FLAIR sequences can effectively identify the labyrinthine high signal, but the latter was better than the former of its ability to display, especially delayed enhanced 3D-FLAIR. The high signal at the ampulla of semicircular canals was a characteristic predictor of non-recovery of hearing.

目的:探讨婴幼儿在非镇静状态下采用16cm宽体探测器行颞骨CT扫描的可行性.方法:选取154例婴幼儿(0～6岁)采用16cm宽体探测器行颞骨CT扫描,分为A和B组,A组为77例在镇静状态下行CT扫描的对照组,B组为77例在非镇静状态下行CT扫描的实验组,两组扫描及重建参数相同,重组横轴面、冠状面图像,测量和计算对比噪声比(CNR),由两位放射医师对图像进行主观评分,并比较分析两组的CNR和图像主观评分有无差异,符合正态分布的数据采用独立样本t检验方法,不符合的采用秩和检验方法.结果:两名医师主观评分一致性良好(Kappa值为0.784).两组主观评分0～1.0岁分别为62.13±4.07和62.35±4.01,1.1～3.0岁为62.15±2.99和63.08±2.32,3.1～6.0岁为62.93±2.89和62.34±4.46,两组之间差异均无统计学意义(P>0.05).两组0～1.0岁横轴面图像CNR分别为14.18±0.44和14.36±0.65,1.1～3.0岁分别为14.24±0.65和13.94±0.46,3.1～6.0岁分别为13.96±0.33和13.96±0.49;两组0～1.0岁冠状面图像的CNR分别为23.43±1.02和23.20±1.20,1.1～3.0岁分别为23.07±1.23和22.77±0.920,3.1～6.0岁为22.59±1.02和22.67±1.06,两组之间差异均无统计学意义(P>0.05).镇静组阳性率85.71％,非镇静组阳性率88.31％.结论:婴幼儿在非镇静状态下使用16厘米宽体探测器行颞骨CT扫描是可行的,其图像质量与镇静状态下图像质量没有差异.

Objective: To explore the value of speculating etiology of the magnetic resonance imaging (MRI) T1 weighted imaging (T1WI) labyrinthine high signal ratio in patients with unilateral sudden deafness accompanied by vertigo and tinnitus and its relationship with hearing prognosis. Methods: Fifty-two patients with unilateral sudden deafness accompanied by vertigo and tinnitus who were admitted to Beijing Tongren Hospital Affiliated to Capital Medical University from January 2016 to July 2019 were collected, including 27 males and 25 females, aged (47.7±15.1) years. The inner ear MRI data of 52 patients (17 plain scan, 35 enhanced scan) with unilateral sudden deafness were retrospectively analyzed. Two radiologists independently measured the labyrinthine high signal intensity of the affected side and the contralateral normal side on T1WI and enhanced T1WI and calculated the signal ratio (the normal labyrinth signal was subtracted from the affected signal and then divided by the normal signal). The etiology of the enhanced group was judged based on two methods, including whether the abnormal high signal was enhanced or not (unenhancement indicated hemorrhage and enhancement indicated inflammation), and the locations of labyrinthine involvement on enhanced three-dimensional fluid attenuated inversion recovery (3D-FLAIR) (inflammation usually involved the perilymph spaces, while hemorrhage involved the perilymph and endolymph spaces). In the plain group, the locations of labyrinthine involvement on 3D-FLAIR was applied to infer the potential etiology. Results: The two methods presumed that 8 cases might be hemorrhage (22.9%, 8/35) and 27 be inflammation (77.1%, 27/35) in the enhanced group, which had a high consistency, while it was speculated that 7 patients might be hemorrhage (7/17) and 10 patients be inflammation (10/17) in the plain group. The measurement results of the two radiologists were highly consistent within and between the groups [the intraclass correlation coefficient (ICC) values were greater than 0.800]. The area under the receiver operating characteristic (ROC) curve (AUC) of the T1WI high signal ratio in the enhanced group for speculating etiology was 0.949 (P<0.01), when the predictive threshold value was 0.467, with a sensitivity of 96.3% and a specificity of 87.5%. It might be hemorrhage when the ratio was higher than the threshold value, otherwise it was inflammation. The T1WI labyrinthine high signal ratio was higher in the hemorrhage group than that of the inflammation group, and the hearing prognosis was worse (all P<0.05). The T1WI labyrinthine high signal ratio of the unrecovered group was higher than that of the recovered group (P=0.034). Conclusions: The etiology of labyrinthine high signal formation can be inferred by quantitative values combined with the involved sites. The high signal in the labyrinth indicates poor hearing prognosis, the higher the signal intensity, the greater the possibility of hemorrhage and the worse the hearing prognosis.

Objective: To investigate the visualization of endolymph in patients with otogenic vertigo by intravenous administration of single dose of gadolinium contrast agents and magnetic resonance three-dimensional fluid-attenuated inversion recovery sequence (3D-FLAIR MRI), and further assess the extent of endolymphatic hydrops. Methods: From Beijing Tongren Hospital of Capital Medical University between October 2017 and June 2018, 30 patients (16 males, 14 females) with unilateral otogenic vertigo were involved in this study, with the age of 30 to 68 years, mean age of (53±10) years. Eight hours after intravenous administration of single dose (0.1 mmol/kg, body weight) of gadopentetate (Gd-DTPA), 3D-FLAIR sequence was performed in 30 patients. The location of endolymphatic hydrops was observed and then the degree of hydrops was quantitatively elevated by two radiologists. The consistency test was used to analyze the location and degree of endolymphatic hydrops in the two radiologists and the paired t-test was used to compare the difference between the affected and healthy side of endolymphatic spaces of the patients with otogenic vertigo. Results: In 30 patients, the gadolinium distributed in all parts of the perilymph inside the inner ear, and can accurately outline the boundaries of the peri-and endolymph. Twenty-six patients (26/30, 86.7%) were found to have unilateral endolymphatic hydrops, including 18 mild hydrops, 8 significant hydrops. The two radiologists had a very good agreement on the assessment of endolymphatic hydrops(kappa=0.864, ICC=0.959). In the 3D-FLAIR MR images of 26 patients with endolymphatic hydrops, the saccule (26/26, 100%) had a higher rate of hydrops than the cochlea and utricle(16/26, 61.5%; 14/26, 53.8%), and two radiologists had a very good agreement on the location of endolymphatic hydrops(kappa=0.820). Moreover, there was a significantly statistical difference between the affected and healthy area of the endolymphatic space in this study (P<0.01). Conclusion: The technique of 3D-FLAIR MR imaging through single dose intravenous gadolinium injection is feasible, which can estimate endolymphatic hydrops in patients with otogenic vertigo, and accurately classify the degree of hydrops.

目的 对比分析半球形与扁平形葡萄膜转移癌的MRI征象,探讨MRI对不同形态葡萄膜转移癌的诊断价值.方法 回顾性收集北京同仁医院2005～2015年经手术病理或临床综合诊断确诊的眼葡萄膜转移癌49例,平均年龄(52.5±12.3)岁,其中男性19例,女性30例,左眼26例,右眼21例,双眼2例,根据病变形态分为扁平形组(36例)和半球形组(13例).比较两组临床表现及MRI征象,包括患者年龄、性别、肿块侧别、部位、形态、边缘、是否伴发视网膜脱离、T1WI和T2WI信号(与脑灰质相比)、T1 WI和T2WI信号均匀度、强化程度、强化均匀度、强化指数、肿块高度、基底径、基底径与高度比值,计数资料采用Pearson卡方检验,计量资料采用独立样本秩和检验.结果 肿块T1WI信号均匀度、增强程度、强化指数在两组间均有显著差异(x2=4.491、5.026、5.914,P=0.034、0.025、0.015),患者性别、侧别、肿块部位、形态、边缘、是否伴发视网膜脱离、T1WI和T2WI信号(与脑灰质相比)、T2WI信号均匀度均无显著性差异(P＞0.05),基底径与高度比值在扁平形组(0.8～11.3mm,中位数2.9mm)和半球形组(1.0 ～ 6.0mm,中位数2.0mm)两组间均有显著差异(Z =-1.998,P=0.046),患者年龄、肿块高度、基底径均无显著性差异(P＞0.05).结论 半球形与扁平形葡萄膜转移癌的MRI征象存在一定差异,半球形葡萄膜转移癌仍具备多数葡萄膜转移癌T1WI、T2WI多呈等信号的特点,MRI对葡萄膜转移癌具有重要价值.

目的 通过周期性旋转重叠平行线采集和增强处理重组(PROPELLER)Duo DW-MRI对鼻腔鼻窦内翻性乳头状瘤(sinonasal inverted papilloma,SNIP)与鼻腔鼻窦鳞状细胞癌MR定量分析,评估表面弥散系数(apparentdiffusion coefficient,ADC)值对鉴别二者的价值.方法 回顾性分析经手术病理证实的SNIP 61例、鼻腔鼻窦鳞状细胞癌41例患者的脂肪抑制PROPELLER Duo DW-MRI资料(b值0、1000 s/mm2),采用病变最大层面感兴趣区(ROI)和局部ROI(ADC值最小区域,圆形,面积30 mm2)两种方法分别测量ADC值(简称最大层面ADC值、最小ADC值).采用独立样本t检验比较两种肿瘤ADC值有无差异,通过ROC曲线分析ADC值对鉴别二者的能力.结果 两种测量方法获取的鼻腔鼻窦鳞状细胞癌的最大层面ADC值、最小ADC值均低于SNIP (P均=0.000),最大层面ADC值大于最小ADC值(P=0.000).以1.46×103mm2/s为临界值,最大层面ADC值鉴别鼻腔鼻窦鳞状细胞癌与SNIP的ROC曲线下面积为0.979;以1.40×103mm2/s为临界值,最小ADC值鉴别鼻腔鼻窦鳞状细胞癌与SNIP的ROC曲线下面积为0.948,最大层面ADC值鉴别鼻腔鼻窦鳞状细胞癌与SNIP的能力高于最小ADC值(P=0.018).结论 PROPELLER Duo DW-MRI在SNIP与鼻腔鼻窦鳞状细胞癌的鉴别诊断中具有重要价值.

Objective To explore the effects on image quality and dose reduction to the lens when using bismuth shielding in head and neck MSCT.Methods The standard phantom and the cadaveric head with none,1,2 and 3 layers of bismuth shielding were scanned with protocols of brain,temporal bone and paranasal sinuses using a 16-MDCT scanner.The organ dose to the lens in each scanning was measured with thermoluminescence dosimeters(TLD).The above scanning with sinus protocol was repeated with a sponge with thickness of 5,10,15 and 20 mm placed between the shielding and phantom/head.The CT attenuation of phantom with the distance of 2,4,6 and 8 cm to shielding were measured.The image quality was subjectively evaluated by 2 physicians.Results The organ doses of the lens with protocols of brain,temporal bone and sinuses were 24.31,27.60 and 20.01 mGy,respectively.The doses were decreased significantly when using bismuth shielding.With the increase of the shield gap,the degree of dose reduction was reduced,but the increasing degree of CT attenuation significantly reduced.Using 2-layer and 3-layer bismuth shield in brain and temporal bone CT scan,the radiation doses were reduced by 47.1％ and 59.1％,respectively while maintaining the diagnostic image quality.Using 1-layer shield without gap and 2-layer shield with 1.5 cm gap in sinus CT,the radiation doses were reduced by 31.5％ and 34.5％,respectively.Conclusions Reasonable usage of bismuth shielding can effectively reduce the radiation dose to the lens of eye in head and neck MSCT.

Objective To investigate the influence of tube voltage on image quality and radiation dosage to subjects in chest digital radiography (DR).Methods An adult chest phantom was exposed in the range of 80-130 kV with the interval of 10 kV and the automatic exposure control (AEC) setting was selected from-4 to 4.The entrance skin dose (ESD) of the phantom was measured,and the relative noise,contrast-to-noise ratio (CNR) and the effective dose of each exposure was calculated.Results The ESD was (0.062 9 ±0.027 4) mGy,and the effective dose was (0.012 7 ±0.004 5) mSv.The effective dose increased linearly with the ESD,and there was a positive correlation (r =0.912,P ＜ 0.01).When the tube voltage was held constant,the relative noise decreased as the effective dose increased (r =-0.967,-0.969,-0.968,-0.969,-0.968,-0.970,P ＜ 0.01).The CNR increased with the effective dose increasing under the same tube voltage(r =0.987,0.987,0.986,0.987,0.988,0.989,P ＜0.01).The ESD and effective dose decreased as the kV values increased under the same AEC,and the degree of decrease could be up to 50％ and 20％.The relative noise decreased as the kV values increased under the same AEC,and the degree of decrease could be up to 23％.The CNR values increased up to 8％.Conclusions The use of higher kVp in chest digital radiography can reduce the radiation dose to some extent

Objective To explore the influence on image quality and the reduction of radiation dose to eye lens when using bismuth shielding in sinus MDCT.Methods The standard water phantom was scanned using clinical scanning protocols of sinus in 16-MDCT,and the images were acquired with none,1 layer,2 layers and 3 layers of bismuth shielding severally.Using the above protocol,the cadaveric head was scanned with no shield,1,2 and 3 layers of bismuth shielding material covered on both eyes,and the organ dose to eye lens in each scanning was measured with thermoluminescence dosimeter (TLD).The sponge with the thick of 0.5,1.0,1.5,2.0 cm was placed between the shielding material and the surface of subjects separately and the radiation doses to eye lens was measured with sinus scanning conditions in the same way.The CT values of phantom with the distances of 2.0,4.0,6.0 and 8.0 cm to shield material were measured.The influence of bismuth artifacts on anatomic structures was evaluated as well.Results The organ doses to the eye lens in the sinus clinical CT were 20.0 mGy.Doses decreased significantly to 13.7,10.9 and 9.4 mGy separately when using 3 types of bismuth shielding thickness.With different thicknesses of shielding material,the greater the shield gap,the smaller the degree of reduction of organ dose,but the increasment of CT value was significantly reduced.Using 1-layer shield no gap and 2-layer shield with 1.5 cm gap in sinus MDCT,the radiation doses were reduced to 13.7 and 13.1 mGy with the reduction rates of 31.5％ and 34.5％ respectively.Conclusion The reasonable bismuth shielding can effectively reduce the radiation dose to eye lens in sinus CT on the premise of ensuring image-diagnostic quality.

Objective To investigate the feasibility of using tube current modulation technique to reduce the radiation dose in CT examination of upper respiratory tract.Methods A total of 99 adult patients were enrolled in this study.The patients were randomly and equally divided into three groups with 33 cases in each group.CT scanning of upper respiratory tract was performed in all patients.In the conventional dose group (group A) the preset effective mAs was 250 mAs/slice,in the Doseright group (group B) the recommended mAs (according to the surview and scanning range) was employed,while in the Z-DOM group (Z axis tube current modulation,group C) the tube current was automatically adjusted by the system according to the positioning in the Z axis direction.During the scanning course the mA value was kept stable in group A and group B,while the mA value was changing in group C; the other parameters used in all three groups were the same.All the images were reconstructed by filtered back projection (FBP) algorithm.The median sagittal images were reformatted with 3 mm thickness,and their corresponding contrast-to-noise ratios (CNR) were calculated; the median sagittal images were subjectively evaluated by five division method (subjective evaluation score).The values of CTDI,CNR,DLP and subjective evaluation score of three groups were statistically analyzed.Results For group A,B and C,the CTDI was (14.70 ± 0.00) mGy,(16.50 ± 2.59) mGy and (4.60 ± 1.99) mGy respectively ; the DLP was (465.87 ± 31.55) mGy · cm,(526.15 ±98.28) mGy · cm and (147.74 ±67.08) mGy · cm respectively; and the differences in radiation doses between each other among the three groups were statistically significant (the F values of CTDI and DLP were 381.24 and 381.24 respectively,P ＜ 0.05).The radiation dose of group B was 10％ higher than that of group A,the dose of group C was significantly lower than that of group A and group B:about 70％ lower than that of group B and 75％ lower than that of group A.The CNR of group A,B and C was 523.91 ± 80.75,540.28 ± 117.65 and 511.09 ± 107.56 respectively,and the differences in CNR between each other among the three groups were statistically significant (F =0.603,P =0.549 ＞ 0.05).The subjective evaluation scores of group A,B and C were 10.5 (10,11.5),11(10.5,11.5) and 12.5 (12.25,13.0) respectively,and the differences in subjective evaluation score between each other among the three groups were statistically significant (chi-square =48.373,P ＜ 0.05):the subjective evaluation score of group B was slightly higher than that of group A (chi-square =0.038,P ＞0.017),the subjective evaluation score of group C was higher than that of group A and group B (chi-square values were 36.972 and 36.972 respectively,P ＜ 0.017).Conclusion The use of Z-DOM technique in CT examination of upper respiratory tract can effectively reduce the radiation dose while higher image quality can be reliably preserved.Therefore,this technique should be recommended in clinical practice.

Objective To find the proper way of assessing the image noise characteristic through the analysis of noise characteristic in the digital mammographic images.Methods The CDMAM phantom was firstly exposed with different filter materials and tube voltages in the range of 23 to 35 kVp at a fixed tube current 90 mAs,then exposed with different filter materials and tube current in the range of 20 to 200 mAs at a fixed tube voltage 29 kVp.The parameters such as background standard deviation,joint standard deviation,subtracted standard deviation and relative standard deviation were calculated and measured from both 60 pixels of signal disc and background beside of the disk for all the images.The IQFinvs were calculated for the achieved images.Non-parametric rank sum tests were used to compare the difference of the background standard deviation,joint standard deviation and subtracted standard deviation,t test was used to compare the IQFinvs between Mo and Rh filers in each group.Results With the same exposure parameters in the test above,the maximum value was the background standard deviation,while the subtracted standard deviation was the minimum,and the value of joint standard deviation was in the middle. With other parameters unchanged,the values of three kind of standard deviation increased with the increasing of tube voltage or tube current,while the differences between them getting more significant.Under the condition of 90 mAs and Mo filter material,background standard deviation,joint standard deviation,subtracted standard deviation were 10.91,10.34 and 9.87,the results were 11.24,10.57 and 9.96 while Rh filter material was used,significant difference was found ( x2 =26.0,P ＜ 0.01 ). Under the condition of 29 kVp and Mo filter material,background standard deviation,joint standard deviation,subtracted standard deviation were 12.30,11.61 and 11.05,the results were 12.29,11.58 and 10.87 while Rh filter material was used,significant difference was found( x2 =20.0,P ＜ 0.01 ).The IQFinvs were 149.14 ± 23.87 and 139.16 ± 23.14 under the condition of 90 mAs and Mo filter material ( t =9.129,P ＜ 0.01 ).The IQFinvs were 149.75 ±34.85 and 145.2 ±34.64 while the parameters were 29 kVp and Rh filter material(t =1.304,P ＞0.05 ).The value of relative standard deviation decreased with the increasing of tube voltage or tube current,and the image quality got better with the decreasing of relative standard deviation.Conclusion Relative standard deviation is suitable not only for the expression of the digital mammographic images,but also for the evaluation of the image quality.

BACKGROUND AND PURPOSE:Iterative reconstruction of CT images is characterized by reduced image noise and may allow reduction in radiation exposure. We investigated the influence of an IRT technique on image quality and radiation dose savings when applied to temporal bone CT.MATERIALS AND METHODS:Based on the typical image quality level of adult subjects using routine radiation dose and FBP, an exsomatized cadaveric head with CNR characteristics closest to the level of clinical subjects was identified. Cadaver acquisitions were performed at multiple levels of tube current exposure. Reconstructions were performed using FBP and IRT (iDose), with multiple iDose levels applied for each acquisition. Transverse and coronal reformations of all reconstructions were evaluated subjectively and objectively. Phantom tests were performed to validate the protocol optimizations with iDose, specifically the spatial resolution relative to routine dose acquisitions. Finally, the results of protocol optimization with iDose were clinically validated in 50 patients.RESULTS:At the same radiation dose, the image CNR of iDose reconstructions was higher than that of FBP and progressively increased with higher iDose levels. The combination of 100 mAs/section and iDoseL5 was the lowest dose that met the requirements for diagnostic acceptability, with CNR slightly higher than our routine institution protocol of 200 mAs/section with FBP reconstruction. Spatial resolution characteristics were similar between FBP and iDose at all different strengths. The findings were consistent among the cadaver, phantom, and clinical acquisitions.CONCLUSIONS:The iDose IRT can help reduce radiation dose of temporal bone CT by 50% relative to routine institution protocols with FBP, while maintaining diagnostic image quality.