Evaluating the use of anti-scatter grids in adult knee radiography

IntroductionAnti-scatter grids efficiently reduce scatter radiation from reaching the imaging receptor, enhancing image quality; however, the patient radiation dose increases in the process. There is disagreement regarding the thickness thresholds for which anti-scatter grids are beneficial. This study aims to establish a thickness threshold for the use of anti-scatter grids to optimise adult knee radiography.MethodsThe study consisted of two phases. In Phase 1 phantom knee radiographs were acquired at varying thicknesses (10–16 cm) and tube voltages (60–80 kV). For each thickness and tube voltage, images with and without an anti-scatter grid were obtained. In Phase 2, two radiologists and three radiographers, evaluated the image quality of these images. Visual Grading Analysis (VGA) scores were analysed using Visual Grading Characteristics (VGC) based on the visualisation of five anatomic criteria.ResultsThe average DAP decreased by 72.1% and mAs by 73.1% when removing the anti-scatter grid. The VGC revealed that overall images taken with an anti-scatter grid have better image quality (AUC ≥0.5 for all comparisons). However, the anti-scatter grids could be removed for thicknesses 10, 12 and 14 cm in conjunction with using 80 kVp,.ConclusionAnti-scatter grids can be removed when imaging adult knees between 10 and 12 cm using any kVp setting since the radiation dose is reduced without significantly affecting image quality. For thicknesses >12 cm, the use of anti-scatter grids significantly improves image quality; however, the radiation dose to the patient is increased. The exception is at 14 cm used with 80 kVp, where changes in image quality were insignificant.Implications for practiceOptimisation by removing anti-scatter grids in adult knee radiography seems beneficial below 12 cm thickness with any kVp value. Since the average knee thickness ranges between 10 and 13 cm, anti-scatter grid can be removed for most patients. Nevertheless, further studies are recommended to test if this phantom-based threshold applies to human subjects.     

Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery: Diagnoses and Surgical Results in 12 Pediatric Patients

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic.     

动态范围压缩技术在CR足部影像中的应用

目的探讨动态范围压缩技术在体厚差别较大的足部CR图像处理中的应用价值。方法回顾性分析成人足部CR图像50例,采用动态范围压缩技术处理用以观察趾周软组织、第1趾甲沟、第5趾骨远侧节、距骨小粱、跟骰关节间隙的清晰显示率,并与常规CR处理图像进行比较。结果经动态范围压缩技术处理后,显示全足组织结构更加清晰,与常规CR图像相比,两者在统计学上存在显著差异(t=7.732,P<0.05)。结论对体厚差别较大的足部CR图像,应用动态范围压缩技术使大量有用信息得以充分利用,能在同一幅图像上同时显示软组织、骨骼及关节结构,具有较大的临床应用价值。     

比较4种影像技术对早期股骨头缺血性坏死的诊断敏感性

目的评价CR,CT,ECT和MRI在早期股骨头缺血性坏死(ANFH)中的诊断价值。方法回顾性分析16例23髋经手术、病理证实为早期(符合国际骨循环研究会(ARCO)分期标准Ⅰ期-Ⅱ期)股骨头缺血性坏死患者的CR,CT,ECT和MRI的影像学特征及其检查结果。结果CR诊断早期ANFH11髋,阳性率为47.8%,CT诊断早期ANFH14髋,阳性率为60.9%,ECT诊断诊断早期ANFH21髋,阳性率为91.3%,MRI诊断早期ANFH22髋,阳性率为95.7%。经统计学处理,X2=19.38,P<0.01,CR,CT,ECT和MRI四者敏感性的差异具有显著性意义。结论对早期股骨头缺血性坏死影像学诊断而言,CR诊断敏感性较低,CT可提供较多的诊断信息,ECT和MRI的敏感性高于CT及CR,MRI可准确地诊断早期股骨头缺血性坏死。     

暴发流行的肺炎衣原体肺炎影像学表现分析

目的研究肺炎衣原体肺炎暴发流行的胸部影像学特征表现。方法对经过痰和咽试子标本,PCR,MIF检测证实的15例暴发流行的肺炎衣原体肺炎住院患者胸部X线和高分辨CT表现进行分析。结果本组暴发流行的肺炎衣原体肺炎患者均有发热,头痛,全身肌肉酸痛,干咳,声音嘶哑,咽痛等症状。肺部呼吸音减低或细湿啰音4例(26.7%),出现明显肺部影像学表现10例(66.7%)。10例暴发流行的肺炎衣原体肺炎常表现为多发或单发以小叶为中心阴影和腺泡状结节影(100%),病变以两中、下肺叶,外、中带分布;以小叶分布的气腔实变和磨玻璃样阴影(分别为100%和40%)和支气管血管束增厚(90%)。无肺门或纵隔淋巴结增大和胸腔积液。结论暴发流行的肺炎衣原体肺炎具有群体发病,临床和影像学表现有相似的特征,早期CT检查更能真实地反映病变大小、多少和分布范围。     

医源性胆管狭窄X线表现

本文报道了１３例医源性胆管狭窄，分析其影像表现。特点为：环形狭窄；线样狭窄，包括规则的和不规则的线样狭窄；闭塞性狭窄；胆管闭塞和胆管中断分离。ＥＲＣＴ和ＰＣＴ对狭窄的形态，位置及长度显示优于ＣＴ和ＵＳ。     

多级图像对比度放大技术在膝关节摄影中的应用

目的:分析评价膝关节摄影中多级图像对比度放大技术(MUSICA)参数设定的成像效果,为实际临床应用提供理论指导。方法:随机抽取膝关节侧位软拷贝图像70例,以骨皮质、骨小梁、肌间隙、髌上囊、皮下脂肪为比对目标,由三位观察者对其显示情况进行分析,并对结果进行统计分析。结果:MUSICA处于较小值(0～2)时,适合于软组织显示,但图像锐利度欠缺;处于较高值时(4～6)适合于观察骨皮质、小梁等细节信息,但较多地出现伪影,共25例;处于2～4时整体影像对比度适中,如实反映人体密度结构。结论:作图像处理时应将MUSICA为2～4设定为常规,实际应用通常情况下可以选择该处理方法,但应根据具体要求适当调整MUSICA参数值。     

直接数字化X线摄影在腰椎侧位影像中的应用价值

目的探讨直接数字化X线摄影（direct digitized radiography，DDR）在腰椎侧位影像中的应用价值。方法随机抽取81例患者的DDR腰椎侧位影像，使用图像后处理方法中多级图像对比增益法，又称“交响乐”功能（multi—scale image contrast amplification，MUSICA）进行后处理，同时取另81例患者进行普通X线摄影，由放射科经验丰富的医生、技师各2名对所有的腰椎侧位影像进行分析，采用常规影像质量评价指标评价两组的影像质量。结果（1）DDR腰椎侧位影像质量影像评分为13．00，普通X线影像评分为8．96，经非参数检验的配对符号秩和检验，依赖负秩计算的统计量（X^2=-7．88，P〈0．01），两组差异有统计学意义，DDR腰椎侧位组明显优于普通平片组；（2）81例中DDR腰椎图像显示满意率为92．6％（75／81），普通X线平片显示满意率为61．7％（50／81），两者差异有统计学意义（X^2=21．89，P〈0．01）。结论与普通X线影像相比，DDR影像能更好的显示下部腰椎椎体、附件及周围软组织，可获得良好的图像，有利于放射诊断工作。     

鼻骨外伤X线摄影技术探讨

本文通过分析鼻骨外伤X线成像特点,重点探讨了常规X线与DR检查在鼻骨外伤中的应用价值,旨在提高对鼻骨骨折诊断的准确率。结果表明DR摄影是鼻骨常规检查的理想手段。