Reduced nontarget embolization and increased targeted delivery with a reflux-control microcatheter in a swine model

PurposeTo evaluate the potential differences in non-target embolization and vessel microsphere filling of a reflux-control microcatheter (RCM) compared to a standard end-hole microcatheter (SEHM) in a swine model.Materials and methodsRadiopaque microspheres were injected with both RCM and SEHM (2.4-Fr and 2.7-Fr) in the kidneys of a preclinical swine model. Transarterial renal embolization procedures with RCM or SEHM were performed in both kidneys of 14 pigs. Renal arteries were selectively embolized with an automated injection protocol of radio-opaque microspheres. Ex-vivo X-ray microtomography images of the kidneys were utilized to evaluate the embolization by quantification of the deposition of injected microspheres in the target vs. the non-target area of injection. X-ray microtomography images were blindly analyzed by five interventional radiologists. The degree of vessel filling and the non-target embolization were quantified using a scale from 1 to 5 for each parameter. An analysis of variance was used to compare the paired scores.ResultsTotal volumes of radio-opaque microspheres injected were similar for RCM (11.5 ± 3.6 [SD] mL; range: 6–17 mL) and SEHM (10.6 ± 5.2 [SD] mL; range: 4–19 mL) (P = 0.38). The voxels enhanced ratio in the target (T) vs. non-target (NT) areas was greater with RCM (T = 98.3% vs. NT = 1.7%) than with SEHM (T = 89% vs. NT = 11%) but the difference was not significant (P = 0.30). The total score blindly given by the five interventional radiologists was significantly different between RCM (12.3 ± 2.1 [SD]; range: 6–15) and the standard catheter (11.3 ± 2.5 [SD]; range: 4–15) (P = 0.0073), with a significant decrease of non-target embolization for RCM (3.8 ± 1.3 [SD]; range: 3.5–4.2) compared to SEHM (3.2 ± 1.5 [SD]; range: 2.9–3.5) (P = 0.014).ConclusionIn an animal model, RCM microcatheters reduce the risk of non-target embolization from 11% to 1.7%, increasing the delivery of microspheres of 98% to the target vessels, compared to SEHM microcatheters.     

The effect of different statistical approaches on image quality data obtained from radiological examinations

IntroductionSelection of optimal image acquisition protocols in medical imaging remains a grey area, the superimposed use of the Likert scale in radiological image quality evaluations creates an additional challenge for the statistical analysis of image quality data.Using a simulation study, we have trialled a novel approach to analysing radiological image quality Likert scale data.MethodsA simulation study was undertaken where simulated datasets were generated based on the distribution of Likert scale values according to varying image acquisition protocols from a real dataset. Simulated Likert scale values were pooled in four different ways; the mean, median, mode and the summation of patient Likert scale values of which the total was assigned a categorical Likert scale value. Estimates of bias, MAPE and RMSPE were then calculated for all four pooling approaches to determine which method most accurately represented an expert's opinion.ResultsWhen compared to an expert's opinion, the method of summation and categorisation of Likert scale values was most accurate 49 times out of the 114 (43.0%) tests. The mean 28 times out of 114 (24.6%), the median 23 times out of 114 (20.2%) and the mode 17 times out of 114 (14.9%).ConclusionWe conclude that our method of summation and categorisation of Likert scale values is most often the best representation of the simulated data compared to the expert's opinion.Implications for practiceThere is scope to reproduce this simulation study with multiple observers to reflect clinical reality more accurately with the dynamic nature of multiple observers. This also prompts future investigation into other anatomical areas, to see if the same methods produce similar results.     

CTA诊断右下肺叶基底段异常体动脉供血1例

患者男,22岁,无明显诱因咳嗽、痰中带血1周,起初干咳,后咳痰并痰中带血,偶咯出少量暗红色血液;无发热、盗汗、乏力,无胸闷、胸痛及呼吸困难,平素体健,无家族病史。查体:双肺呼吸音稍粗,右肺下叶闻及细湿啰音。胸部增强CT:右肺下叶基底段见片状磨玻璃影,内见直径约8mm粗大供血动脉自腹腔干发出;支气管树分支及肺发育正常,未见隔离肺(图1A^1C)。肺动脉CTA示右下肺基底段动脉部分缺如(图1D),考虑为右下肺异常体动脉供血并周围肺组织肺泡出血可能。     

Manejo y seguimiento radiológico del paciente post-COVID-19

Most of the patients who overcome the SARS-CoV-2 infection do not present complications and do not require a specific follow-up, but a significant proportion (especially those with moderate / severe clinical forms of the disease) require clinicalradiological follow-up. Although there are hardly any references or clinical guidelines regarding the long-term follow-up of post-COVID-19 patients, radiological exams are being performed and monographic surveillance consultations are being set up in most of the hospitals to meet their needs. The purpose of this work is to share our experience in the management of the post-COVID-19 patient in two institutions thathave had a high incidence of COVID-19 and to propose general follow-uprecommendations from a clinical and radiological perspective.     

Building and Exploitation of Learning Curves to Train Radiographer Students in X-Ray CT Image Postprocessing

IntroductionThis study aims to construct learning curves related to the realization of standardized postprocessing by radiographer students and to discuss their exploitation and interest.Materials and MethodsThis study was carried out in 21 French students in their 3rd year of training. Two postprocessing protocols in CT (#1 traumatic shoulder; #2 petrous bone) were repeated 15 times by each student. Each achievement was timed to obtain overall learning curves. The realization accuracy was also assessed for each student at each repetition.ResultsThe learning rates for the two protocols are 63% and 56%, respectively. The number of repetitions to reach the reference time for each protocol is 11 and 12, respectively. In both protocols, the standard deviations are significantly reduced and stabilized during repetitions. The mean accuracy progresses more quickly in protocol #1.DiscussionThe measured learning rates reflect a rapid learning process for each protocol. The analysis of the standard deviations shows that students have reached a homogeneous level. The average times and accuracies measured during the last repetitions show that the group has reached a high level of performance. Building learning curves helps students measure their progress and motivates them.ConclusionObtaining learning curves allows trainers/supervisors to qualify the learning difficulty of a task while motivating students/radiographers. The use of learning curves is inline with the competency-based training paradigm.     

Analysis of radiation exposure data from common radiological procedures in Dutch hospitals

IntroductionIn the Netherlands, Diagnostic Reference Levels (DRLs) have not been based on a national survey as proposed by ICRP. Instead, local exposure data, expert judgment and the international scientific literature were used as sources. This study investigated whether the current DRLs are reasonable for Dutch radiological practice.MethodsA national project was set up, in which radiography students carried out dose measurements in hospitals supervised by medical physicists. The project ran from 2014 to 2017 and dose values were analysed for a trend over time. In the absence of such a trend, the joint yearly data sets were considered a single data set and were analysed together. In this way the national project mimicked a national survey.ResultsFor six out of eleven radiological procedures enough data was collected for further analysis. In the first step of the analysis no trend was found over time for any of these procedures. In the second step the joint analysis lead to suggestions for five new DRL values that are far below the current ones. The new DRLs are based on the 75 percentile values of the distributions of all dose data per procedure.ConclusionThe results show that the current DRLs are too high for five of the six procedures that have been analysed. For the other five procedures more data needs to be collected. Moreover, the mean weights of the patients are higher than expected. This introduces bias when these are not recorded and the mean weight is assumed to be 77 kg.Implications for practiceThe current checking of doses for compliance with the DRLs needs to be changed. Both the procedure (regarding weights) and the values of the DRLs should be updated.     

CT动态增强鉴别肾上腺乏脂肪腺瘤与肾上腺结节样增生的价值

目的探讨CT动态增强对鉴别肾上腺乏脂肪腺瘤与肾上腺结节样增生的价值。方法回顾性分析经手术病理证实的12例肾上腺乏脂肪腺瘤和27例肾上腺结节样增生患者的病例资料,统计两组病例各期增强CT值,利用公式灌注值P=CT静脉期-CT平扫期、廓清值C=CT静脉期-CT延迟期、绝对廓清灌注指数APC=(C/P)×100%及相对廓清灌注指数RAPC=(C/CT静脉期)×100%得到相关参数,并通过绘制受试者工作特征曲线,鉴别两者的最佳价值。结果肾上腺乏脂肪腺瘤直径较结节样增生更大;肾上腺乏脂肪腺瘤病灶各期CT值均明显高于结节样增生,且两者灌注值P、廓清值C、APC及RAPC有明显的统计学差异。年龄、性别、高血压、病灶位置、对侧肾上腺萎缩及动脉期CT值对鉴别两者无显著意义。结论CT动态增强扫描有助于鉴别肾上腺乏脂肪腺瘤和肾上腺结节样增生。     

非活动性结核性胸膜炎与活动性结核性胸膜炎的CT扫描影像特征分析

目的: 探讨非活动性结核性胸膜炎与活动性结核性胸膜炎CT扫描影像表现。方法: 对2012年6月1日至2021年3月30日在首都医科大学附属北京胸科医院就诊的单纯非活动性结核性胸膜炎患者68例和同期活动性结核性胸膜炎44例的CT扫描影像表现进行比较。结果: (1) 68例非活动性结核性胸膜炎患者 CT扫描影像表现中胸膜粘连62例(91.2%),胸膜有钙化者28例(41.2%),叶间裂受累22例(32.4%),胸腔积液12例(17.6%),包裹性胸腔积液8例(11.8%)。(2)44例活动性结核性胸膜炎患者CT扫描影像表现中胸膜粘连30例(68.2%),未见胸膜钙化,叶间裂受累32例(72.7%),胸腔积液43例(97.7%),包裹性胸腔积液26例(59.1%)。(3)非活动性与活动性结核性胸膜炎CT扫描影像比较:胸膜粘连、胸膜钙化发生率高,差异均有统计学意义(χ²=9.630,P=0.002;χ²=23.737,P=0.000);叶间裂受累、胸腔积液、包裹性胸腔积液的发生率低,差异均有统计学意义(χ²=12.692,P=0.000;χ²=68.548,P=0.000;χ²=28.301,P=0.000)。结论: 非活动性结核性胸膜炎的CT扫描影像与活动性结核性胸膜炎比较胸膜粘连、胸膜钙化的发生率高,胸腔积液、包裹性胸腔积液、叶间裂受累的发生率低。识别非活动性和活动性结核性胸膜炎的CT扫描影像特点,对患者临床治疗有指导意义。