Effect of image quality and motivation of radiographer teams in mammography after dedicated training and the use of an evaluation tool like PGMI

IntroductionHigh quality and motivated staff are key factors for successful breast imaging teams. The aim of this study is to find out what effects intensive training of already experienced radiographers - including the embedment of evaluation tools and building a new routine workflow - has on image quality and how the motivation and satisfaction of employees change by that.MethodsA mixed methods study was planned to show changes in image quality simultaneously to motivation of the team after a dedicated training with an expert. Two readers evaluated the quality of 1496 mammograms (775 before, 721 after training) with PGMI (perfect/good/moderate/inadequate) in consensus. To record subjective long-term experiences of the alterations due to the training the radiographers were asked to fill in a written questionnaire.ResultsAfter training the PGMI values considerably shift to a preferred level (p < 0.05) – higher values for P (8,9% to 25,5%) and G (38,2% to 57,1%) and lower values for M (34,1% to 15,4%) and I (18,8% to 1,9%). All radiographers have experienced noticeable improvement and benefit through the initiation of the training.ConclusionAfter training there is significant improvement in the image quality of mammograms and an increase in motivation and professional well-being of the radiographers.Implications for practiceDue to the urgent need for high quality in breast diagnostics and the worldwide frequency of mammographic examinations, investments should be made to establish thoughtful training programs for radiographers and further develop possibilities for assessment like PGMI.     

The current status of digital mammography

Digital imaging has shown rapid advances in recent years. Various different digital mammography systems are now available for clinical use. Digital mammography does have clear advantages over traditional screen film mammography, but this is yet to convincingly translate into improved cancer detection rates. This review aims to describe the different technologies, introduce concepts related to image quality and review the current evidence for the use of digital mammography systems in clinical practice. Advanced applications of digital mammography such as computer-aided detection (CAD) are also discussed.     

Variants of sternal insertion of the pectoral muscle on mammography: a pictorial review

The aim of this pictorial review is to demonstrate the diverse presentations of the medial insertion of pectoralis major on mammography. A collection of cases demonstrating the variations in appearance of this muscle insertion are presented. The factors contributing to the appearances of this artifact, the differential diagnoses and useful further investigations are discussed. Familiarity with the different presentations of this muscle insertion will facilitate recognition and prevent unnecessary investigations.     

CR系统在乳腺摄影中的应用分析

目的:评价CR系统在乳腺摄影中的应用价值。方法:抽取我院CR乳腺照片和传统钼靶X线照片各800张进行分析,统计出甲、乙、丙级片及废片率;统计CR片及传统屏-片乳腺癌的诊断正确率。结果:①照片影像质量:CR照片甲级片率67%,乙级片率26%,丙级片率7%,废片率0.25%。传统屏-片甲级片率36%,乙级片率50%,丙级片率11%,废片率2.5%。②照片诊断正确率:CR照片90%,传统屏-片73%。③摄影条件:CR系统比屏-片系统摄影管电压低4 kV,曝光量低4 mAs。结论:CR摄影影像质量好于传统屏-片摄影,可为临床提供可靠的诊断依据,且减少了病人的X线接受剂量。     

Fusion of dynamic contrast-enhanced magnetic resonance mammography at 3.0T with X-ray mammograms: pilot study evaluation using dedicated semi-automatic registration software

Rationale and objectives

To evaluate the semi-automatic image registration accuracy of X-ray-mammography (XR-M) with high-resolution high-field (3.0 T) MR-mammography (MR-M) in an initial pilot study.

Material and methods

MR-M was acquired on a high-field clinical scanner at 3.0 T (T1-weighted 3D VIBE ± Gd). XR-M was obtained with state-of-the-art full-field digital systems. Seven patients with clearly delineable mass lesions >10 mm both in XR-M and MR-M were enrolled (exclusion criteria: previous breast surgery; surgical intervention between XR-M and MR-M).XR-M and MR-M were matched using a dedicated image-registration algorithm allowing semi-automatic non-linear deformation of MR-M based on finite-element modeling. To identify registration errors (RE) a virtual craniocaudal 2D mammogram was calculated by the software from MR-M (with and w/o Gadodiamide/Gd) and matched with corresponding XR-M. To quantify REs the geometric center of the lesions in the virtual vs. conventional mammogram were subtracted. The robustness of registration was quantified by registration of X-MRs to both MR-Ms with and w/o Gadodiamide.

Results

Image registration was performed successfully for all patients. Overall RE was 8.2 mm (1 min after Gd; confidence interval/CI: 2.0-14.4 mm, standard deviation/SD: 6.7 mm) vs. 8.9 mm (no Gd; CI: 4.0-13.9 mm, SD: 5.4 mm). The mean difference between pre- vs. post-contrast was 0.7 mm (SD: 1.9 mm).

Conclusion

Image registration of high-field 3.0 T MR-mammography with X-ray-mammography is feasible. For this study applying a high-resolution protocol at 3.0 T, the registration was robust and the overall registration error was sufficient for clinical application.     

Optimisation of radiographic acquisition parameters for direct digital radiography: A systematic review

IntroductionThe objective of this systematic review was to uncover and synthesise all available literature regarding appropriate acquisition parameters for direct digital radiography. It sought to either confirm current practices as optimal, or to uncover practices that may produce more optimised results.MethodsA comprehensive search of published and unpublished literature was undertaken to find studies that evaluated how adjustment of different acquisition parameters affected subjective image quality and patient radiation dose. Eight hundred and fifty-eight studies were retrieved for title and abstract screening. Eighty-nine studies were retrieved for full-text screening, and 23 were included for review and methodological quality screening.ResultsNarrative synthesis of the 23 included studies revealed limited evidence to guide any potential change or acceptance of currently accepted best practice. Meta-analysis was unable to be performed for any of the included studies due to high levels of methodological heterogeneity. A key finding of this review was that the goals of optimisation research varied greatly across the included studies.ConclusionSignificant methodological heterogeneity in the included studies limited the number of clinically relevant findings that would give evidence to an acceptance of, or suggest changes to, currently accepted best practice. Improving consistency in approach across future works of technique optimisation will ensure future systematic reviews will be able to provide strong evidence and meta-analysis will be able to be performed.Implications for clinical practiceThis review highlights that in the literature, studies of optimisation of radiographic acquisition parameters have varying goals. This methodological heterogeneity limits the applicability of systematic reviews and precludes the use of meta-analysis. The authors recommend that a framework for optimisation research be produced as a priority to help improve homogeneity in future research.     

全数字乳腺摄影机最佳曝光条件的探讨

目的 探讨并找出全数字乳腺摄影机(FFDM)的最佳曝光条件。方法 用全数字乳腺X 线摄影机对Fluke NA 18-220 乳腺模体进行自动曝光控制(AEC)摄影,记录曝光条件为29kV、40mAs,用手动调整不同的mAs值(24、28、32、36和45mAs)和kV (22、23、25、27和31kV)对模体曝光,由4位影像学家在相同条件下进行软阅读,并按照美国放射学会(ACR)的评分标准对模体中的钙化点、尼龙纤维、肿块灶进行打分,对所得数据进行方差分析(ANOVA)。结果 在相同的摄影电压29 kV下,手动曝光条件下32mAs和AEC的40mAs的影像信息的评价分值差异没有统计学意义(P>0.05),说明这2种摄影条件对乳腺摄影体模内容物的显示基本相同,但二者的辐射剂量确有明显的不同。在相同的摄影电流40mAs下,27kV和29kV的影像信息的评价分值没有统计学意义(P>0.05),说明这2种摄影条件对乳腺摄影体模内容物的显示基本相同,但二者的辐射剂量不相同。结论 在保证影像质量的前提下,自动曝光控制摄影条件初始设定水平的合理性应进行必要的检测来验证。     

Microdensitometric analysis of bone structures in X-ray images

The careful evaluation of bony structure is important in the study of normal bone and bone disorders. This study describes bony structure as seen in the X-ray pattern of the phalanges of the hand using quantitative microdensitometry. Normalised scans of bony density show the regular and irregular distribution of the trabeculae. Two properties were determined from these densitometric findings: the mean transverse coarseness (C) indicating fluctuations of horizontal density and the overall standard deviation indicating axial homogeneity (H). This investigation demonstrates the applicability of the method: it shows a significant correlation with radiological diagnosis and that microdensitometry is a reliable method for quantifying the coarseness and homogeneity of bone structure.     

采集时间、注射药量与正电子发射体层摄影术图像质量

目的通过对患者体内^18F-氟脱氧葡萄糖（^18F-FDG）剂量、采集持续时间和正电子发射体层摄影术（PET）图像质量进行相关性分析,深入了解获得高质量诊断图像的必要条件,指导图像采集工作。方法采用GE公司Discovery ST型正电子发射体层摄影术／计算机体层摄影术（PET／CT）仪对9例患者进行容积成像协议（VIP）3D采集。使用VIP程序提取2、2．5、3min原始数据序列进行图像重建,使用CT对PET图象进行衰减校正。两位有经验的核医学科医生通过视觉判断法对图像质量进行分级。选择没有肝脏病变的PET图像,将感兴趣区（ROI）置于肝脏面积较大的横断面和冠状面图层的肝区,计算ROI内的放射性计数、标准摄取值（SUV）。使用SPSS10．0软件包对结果进行相关性分析。结果采集9例患者的VIP原始数据进行重建,得到Ⅰ级图像11个,Ⅱ级图像13个,Ⅲ级图像3个。放射性计数中位值：Ⅰ级图像5308个,Ⅱ级图像3683个,Ⅲ级图像3245个。Spearman相关性分析结果显示肝区计数与图像质量分级间呈负相关,r=-0．769,P=0．001（2-tailed）。结论受检者体内足够的放射性计数以及适当的图像采集时间是获得高质量PET图像的前提和保证,且两者相辅相成。     

Image quality, lesion detection, and diagnostic efficacy in digital mammography: full-field digital mammography versus computed radiography-based mammography using digital storage phosphor plates

OBJECTIVE: To compare image quality, the lesion detection, and the diagnostic efficacy of full-field digital mammography (FFDM) and computed radiography-based mammography using digital storage phosphor plates (DSPM) in the evaluation of breast lesions. MATERIALS AND METHODS: In this prospective study, 150 patients with suspicious breast lesions underwent FFDM and DSPM. Nine aspects of image quality (brightness, contrast, sharpness, noise, artifacts, and the detection of anatomic structures, i.e., skin, retromamillary space, glandular tissue, and calcifications) were evaluated by five radiologists. In addition, the detection of breast lesions and the diagnostic efficacy, based on the BI-RADS classification, were evaluated with histologic and follow-up correlation. RESULTS: For contrast, sharpness, and the detection of all anatomic structures, FFDM was rated significantly better (p<0.05). Mass lesions were equally detected, whereas FFDM detected more lesions consisting of calcifications (85 versus 75). DSPM yielded two false-negative results. Both lesions were rated BI-RADS 4 with FFDM, but BI-RADS 2 with DSPM. Both were invasive carcinoma at histology. The sensitivity, specificity, PPV, NPV, and accuracy of FFDM were 1.0, 0.397, 0.636, 1.0, and 0.707, compared to 0.974, 0.397, 0.630, 0.935, and 0.693 of DSPM. CONCLUSION: Based on image quality parameters, FFDM is, in part, significantly better than DSPM. Furthermore, the detection of breast lesions with calcifications is favorable with FFDM. However, the diagnostic efficacy of FFDM and DSPM was equal. The interpretation of the false-negative results suggests that the perception and characterization of breast lesions is not defined solely by the digital mammography system but is strongly influenced by the radiologist, who is one of the determinants in the interpretation of breast imaging.     

Evaluation of manual vs semi-automated delineation of liver lesions on CT images

In this paper we compare a semi-automated delineation method with totally manual delineation for area quantification, with respect to efficiency, quality, and intra- and interobserver variability. Liver lesions on 28 CT images were delineated by three observers, twice using completely manual delineation and twice using a semi-automated method. Quantitative comparisons were performed with respect to delineated area and time required for the delineation tasks. Subjective comparisons were performed with respect to efficiency and perceived quality of the semi-automated method. The areas obtained using semi-automated delineation were significantly smaller (11 %) than those obtained using totally manual delineation. Intraobserver and interobserver variability with the semi-automated method were approximately three times lower than with manual delineation. Efficiency of the semi-automated method was subjectively rated favorable, although further improvements are possible. With respect to quality, the semi-automated method was ranked better than the manual method in 73 % of cases. Received 10 January 1996; Revision received 15 May 1996; Accepted 19 July 1996     

Accuracy of radiographer comment following a two-month experiential and blended learning in appendicular skeleton X-ray interpretation: The Singapore experience

IntroductionThe value of combined blended and experiential learning on radiographer diagnostic comment has not been explored. This study aims to examine the accuracy of image interpretation comment of radiographers who received a period of blended and experiential learning in Radiographer Abnormality Detection Systems (RADS).MethodsWe evaluated the diagnostic opinions of 13 radiographers who received a blended training and experiential learning (a process of self-learning and reflection) in RADS. Radiographers' opinions on 16,483 images were examined using the final radiologists’ report as a reference standard. For each radiographer, we recorded the number of true positive, true negative, false positive and false negative opinions and MedCal® was used to calculate diagnostic performance and error rates. A t-test was used to assess whether the number of images read was associated with performance and whether the radiographers retained performance over time.ResultsSensitivity ranged from 87.4 (84.0–90.2) to 98.9 (97.5–99.7) with a mean of 94.3 (93.6–94.8). Specificity varied from 96.4 (94.8–97.5) to 99.9 (99.41–100.0) with a mean of 98.2 (97.9–98.4). Diagnostic accuracy ranged from 93.1 (91.5–94.4) to 99.5 (98.9–99.8) with a mean of 96.9 (96.6–97.1). The mean false positive rate was 0.018 (range: 0.010–0.031) with a false negative rate of 0.057 (range: 0.026–0.11). There were no differences in performance between the first and latter nine months of providing opinions and the number of images reviewed was not associated with performance.ConclusionRadiographers who received blended and experiential learning in RADS provide accurate diagnostic comments on plain emergency appendicular skeleton radiographs.Implication for practiceA combined blended and experiential learning can equip radiographers to provide diagnostic opinion on plain appendicular skeleton radiographs.     

The effect of anticipation in the scoring of mammographic accreditation phantom images

Purpose: Some of the subjectivity in the scoring of mammographic phantom images may be due to reader anticipation of the pattern of structures in the phantom. The extent of this bias was investigated by scoring images in which the positions of the structures were randomized.Methods: Images of the American College of Radiographers (ACR) mammography phantom were acquired under different X-ray techniques, digitized and scored by a group of five readers. The 16 structures comprising each image were then randomized in position to form new images, which were re-scored by the readers using the same criteria for visibility.Results: The scores after randomization were significantly lower than before randomization, indicating that a priori knowledge of the positions of the structures within the phantom resulted in false-positive scoring of individual structures and elevated net scores for the non-randomized images.Conclusions: Biased scoring due to reader anticipation of the phantom pattern contributes to the inherent subjectivity of the assessment mechanism. Computerized analysis of the phantom images would remove this bias and replace the arbitrary scoring system currently employed with an image quality index better correlated to clinical diagnostic quality.     

两种数字乳腺X射线摄影系统的比较

目的探讨比较全视野数字乳腺X射线摄影系统(FFDM)与计算机乳腺X射线摄影系统(CRM)在影像质量与辐射剂量方面的差异。方法用FFDM对ALVIM乳腺摄影体模TRM进行自动曝光控制(AEC)摄影,再用CRM专用成像板(IP)在同一摄影机上用相同条件对体模摄影。固定AEC摄影时的kV值,选用曝光量数值14、16、18、22和24 mAs,在FFDM机上对模体摄影,记录上述摄影条件和入射皮肤剂量(ESD)及平均腺体剂量(AGD)。由5位影像科资深医师分别在相同条件下对所得影像进行软阅读,按照5分值判断法评判,然后绘制受试者工作特征曲线(ROC)曲线,计算出每种信号的判断概率值(P_det),对所得数据进行统计学分析。结果在辐射剂量均为1.36 mGy时,FFDM对模体内钙化点和肿块灶P_det值比CRM高,尤其是微小钙化点和小肿块灶,微小钙化点最大差值为0.215,小肿块灶最大差值为0.245。在相同的P_det值下,FFDM的辐射剂量比CRM低,ESD的值降低了26%,腺体平均剂量降低了41%。在使用FFDM摄影时,当mAs值超过AEC值时,P_det值没有明显改变。结论在相同曝光条件下,FFDM对乳腺钙化点和肿块灶的检出率高于CRM;在获得相似图像质量时,FFDM的辐射剂量明显低于CRM。     

Image quality assessment of three cone beam CT machines using the SEDENTEXCT CT phantom

Objectives:

The SEDENTEXCT Project proposed quality assurance (QA) methods and introduced a QA image quality phantom. A new prototype was recently introduced that may be improved according to previous reports. The purpose of this study is to evaluate image quality in various protocols of three cone beam CT (CBCT) machines using the proposed QA phantom.

Methods:

Using three CBCT machines, nine image quality parameters, including image homogeneity (noise), uniformity, geometrical distortion, pixel intensity value, contrast resolution, spatial resolution [line pair (LP) chart, point spread function (PSF) and modulation transfer function (MTF)] and metal artefacts, were evaluated using a QA phantom proposed by SEDENTEXCT. Exposure parameters, slice thickness and field of view position changed variously, and the number of total protocols was 22.

Results:

Many protocols showed a uniform gray value distribution except in the minimum slice thickness image acquired using 3D Accuitomo 80 (Morita, Kyoto, Japan) and Veraviewepocs 3Df (Morita). Noise levels differed among the protocols. There was no geometric distortion, and the pixel intensity values were correlated with the CT value. Low contrast resolution differed among the protocols, but high contrast resolution performed well in all. Many protocols showed that the maximum line pair was larger than 1 LP mm⁻¹ but smaller than 3 LP mm⁻¹. PSF and MTF did not correlate well with the pixel size. The measured metal artefact areas varied for each device.

Conclusions:

We studied the image quality of three CBCT machines using the SEDENTEXCT phantom. Image quality varied with exposure protocols and machines.     

The use of reference image criteria in X-ray diagnostics: an application for the optimisation of lumbar spine radiographs

To ensure that sufficient image quality is obtained in diagnostic radiology, the image quality of clinical radiographs has to be evaluated. We present two methods herein for evaluating antero-posterior (AP) radiographs of the lumbar spine. One was using image criteria, including six anatomical details (absolute method). In the other, the visibility of anatomical details relative to a reference radiograph was evaluated (visual grading analysis). In total, 14 technique groups were evaluated. The technique groups differed in tube voltage and detector system characteristics. Six different gradients of the H&D curves were simulated. The visual grading analysis showed larger differences in image quality compared with the absolute method. The influence on the image quality due to a variation in tube voltage was easier to detect than the influence on the image quality from the detector characteristics. The visibility of the anatomical details was significantly dependent on the location in the spine. The visual grading analysis was found to be the preferable evaluation method in studies such as the present; however, it is necessary to guide and train the observer before the evaluation is performed.