Application of panoramic radiography with a multilayer imaging program for detecting proximal caries: a preliminary clinical study

Objective:The aim of this study is to introduce a novel program of panoramic radiography that shows 41 multilayer images from the buccal to lingual aspects in a region of interest, and to evaluate the effectiveness of this program for detecting proximal caries.Methods:In total, 480 premolars and molars on 30 panoramic radiographs taken with the multilayer imaging program were included in this study. The presence or absence of caries in 960 proximal surfaces was assessed by three experienced oral and maxillofacial radiologists as a consensus-based gold-standard. Two general dentists evaluated and scored proximal caries on 980 surfaces on panoramic radiographs with and without the multilayer imaging program. The two general dentists’ scores were compared with the gold-standard, and were analyzed for sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic (ROC) curve with and without using the program. The area under the ROC curve was analyzed using STATA/SE 13.1.Results:When the multilayer imaging program was used for panoramic radiography, the inter- and intraobserver agreement of the two general dentists improved. All values, including the area under the ROC curve, were higher when the multilayer imaging program was used than when it was not used. The area under the ROC curve showed a statistically significant improvement only in Observer 1, whose diagnostic ability was poorer than that of Observer 2.Conclusions:oThis multilayer imaging program might help the inexperienced dentist to improve the diagnostic accuracy of proximal caries. If further studies would be performed in various clinical application, it could be useful when intraoral radiography taking is difficult for reasons such as mouth-opening limitations and the gag reflex of the patients.     

Evaluation of edge enhancement effect of phase contrast imaging using newly-developed photostimulable phosphor plate

We investigated whether the use of a newly developed columnar-crystal-type photostimulable-phosphor plate (CP1M200, referred to as system C) helps to provide improved edge-enhanced effect in phase contrast imaging. Physical characteristics of 2 conventional particulate-crystal-type photostimulable-phosphor plates (RP-5PM, referred to as system A and RP-6M, referred to as system B) and system C were measured. Then, an acrylic plate phantom and RMI152 phantom were imaged using 3 types of plates, and the edge-enhancement effects were evaluated based on the profile curve of the acrylic plate phantom. Visual evaluation of the RMI152 phantom images was conducted. The results showed that the modulation transfer function (MTF) of system C was superior to those of the other systems. The WS of system C was superior to those of the other systems in the low frequency band region, and inferior to those of the other systems in the high frequency band region. The presence of an edge-enhanced image was not detectable in the profile curve of the acrylic plate in system A, although that was shown in systems B and C due to their excellent sharpness. In the visual image evaluation of the RMI152 phantom, image quality of system C was superior to those of the other systems. Phase contrast imaging with a digital detector of a columnar-crystal-type photostimulable-phosphor plate is considered to provide improved edge-enhancement over that of conventional plates.     

An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries

Aim

The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries.

Methods

A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8× magnification.

Results

CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found.

Conclusion

The CBCT system may be used as an auxiliary method for the detection of caries.     

Radiographic modalities for diagnosis of caries in a historical perspective: from film to machine-intelligence supported systems

Radiographic imaging for the diagnosis of caries lesions has been a supplement to clinical examination for approximately a century. Various methods, and particularly X-ray receptors, have been developed over the years, and computer systems have focused on aiding the dentist in the detection of lesions and in estimating lesion depth. The present historical review has sampled accuracy ex vivo studies and clinical studies on radiographic caries diagnosis that have compared two or more receptors for capturing the image. The epochs of film radiography, xeroradiography, digital intraoral radiography, panoramic radiography and other extraoral methods, TACT analysis, cone-beam CT and artificial intelligence systems aiding in decision-making are reviewed. The author of this review (43 years in academia) has been involved in caries research and contributed to the literature in all the mentioned epochs.     

一种新生儿床旁X射线摄影装置辐射防护的临床可靠性研究

目的 分析新生儿床旁摄影防护和体位固定装置在新生儿床旁X射线摄影中的临床价值。方法 使用移动式X射线诊断机对仿真儿童体模进行投照,实验分为A组常规床旁摄影模式;B组使用床旁X射线摄影防护装置。分别在投照部位和辐射敏感部位放置X射线诊断水平剂量仪。以胸部、骨盆、头颅3个部位为投照中心,采集并记录投照部位和辐射敏感部位的辐射剂量。结果 以胸部为投照中心时,B组较A组非投照部位眼晶状体、甲状腺、性腺辐射剂量显著降低94.4%、96.9%、96.7%(t=-152.55、-445.16、-129.07,P＜0.05);以骨盆为投照中心时,B组较A组非投照部位眼晶状体、甲状腺、胸腺辐射剂量降低85.5%、87.1%、94.9%(t=-50.68、-194.18、-535.94,P＜0.05);以头颅为投照中心时,B组较A组非投照部位甲状腺、胸腺、性腺辐射剂量降低99.3%、97.4%、94.3%(t=-1859.97、-542.08、-66.26,P＜0.05)。结论 新生儿床旁X射线摄影中使用新生儿床旁摄影防护和体位固定装置可以显著降低患儿非投照区域的辐射剂量,同时具有固定和保护患儿的功能,提升了检查成功率。     

Dose reduction in general radiography for adult patients by use of a dual-side-reading photostimulable phosphor plate in a computed radiography system

Our purpose in this study was to evaluate the potential of dose reduction in general radiography for adult patients by use of a dual-side-reading (DSR) photostimulable phosphor plate in a computed radiography system. The image quality and low-contrast detectability in terms of the contrast-detail diagram of the DSR system with use of the X-ray beam quality of the RQA 5 defined by the International Electrotechnical Commission 61267 were compared with those of a conventional single-side-reading (SSR) system. The radiographic noise of the DSR system was lower compared to that of the SSR system under the same exposure conditions. Although there were no statistical differences in low-contrast detectabilities between the SSR system and the DSR system under the same exposure levels, the DSR system showed superior detectability compared to the SSR system. We conclude that the DSR system for general radiography has the potential to reduce the patient dose.     

非晶硒平板探测器DR与CR模拟病变描述和剂量降低的对比研究

目的 比较非晶硒平板探测器DR与CR对模拟肺部病变的描述,并对剂量降低情况进行评价。方法 模拟线状、网状和结节病变结构置入仿真胸部体模内,应用DR和CR分别对不同mAs设置的体模曝光,记录体模的入射体表剂量。收集不同剂量的硬拷贝照片,由4位放射医师随机地实施模拟肺部病变显示度评价。采用秩和(Wilcoxon)检验进行统计学分析。结果 用2.0、3.2 mAs曝光时,DR与CR对模拟线状、网状病变的显示度差异有统计学意义(模拟线状病变:Z=-2.032,P=0.042;Z=-2.375, P=0.018。模拟网状病变: Z=-2.680, P=0.007;Z=-2.670, P=0.008)。用5.0、6.3 mAs曝光时,两者对模拟线状、网状病变的显示度差异无统计学意义(P＞0.05)。2.0、3.2、5.0、6.3 mAs曝光档,对于小结节(直径小于10 mm)的检测DR均优于CR(Z=-2.237, P=0.018; Z=-2.384, P=0.017; Z=-2.388, P=0.017; Z=-2.366, P=0.018)。当3种模拟肺部病变都显示清楚时,用非晶硒DR系统的入射体表剂量降低约65%。结论 对微小低对比病变的描述,非晶硒平板探测器DR优于CR且明显地降低曝光剂量。     

直接数字X线摄影在尘肺病诊断中的应用价值

目的 探讨直接数字X线摄影(DR)在尘肺病诊断中的应用价值.方法 对随机抽取的298例接尘对象分批组织同期分别摄高仟伏和DR胸片,先由6名具有尘肺病诊断资质的医师随机均分甲、乙两组分别进行诊断,然后甲、乙两组合并阅片,使分组诊断不一致的结果得到统一.对DR和高仟伏两种胸片统一后诊断的胸片质量、小阴影的形态和大小、总体密集度、小阴影分布肺区数、尘肺分期等结果进行分析比较.结果 DR胸片质量等级集中在优片(97.99％),高仟伏胸片集中在良片(93.63％);DR胸片和高仟伏胸片小阴影的形态和大小、小阴影总体密集度、尘肺分期经一致性检验Kappa值分别为0.642、0.406、0.436,符合率分别为88.26％(263/298)、67.79％(202/298)、65.77％(196/298);小阴影分布肺区数在下肺区DR胸片明显多于高仟伏胸片.结论 DR胸片质量明显优于高仟伏胸片,可用于尘肺病的诊断.     

36例小胃癌临床X线征象分析

目的:探讨数字设备诊断小胃癌及微小胃癌的临床价值。方法:应用多功能数字X线机及胃精细法钡气造影,全部病例由胃镜活检和/或外科手术后病理证实。结果:24例患者做出癌或可疑癌的诊断,11例报告为糜烂性胃炎、良性小溃疡,X线漏诊1例,病灶检出率99.7%。检出6~10 mm病灶31例,3.5~5 mm病灶4例,2.8 mm病灶1例。结论:数字图像可清晰显示胃的微细结构,胃精细法造影对小胃癌及微小胃癌检出率高。“间歇检查法”对发现小而浅的病灶帮助很大,可提高本病的诊断率。     

Incorrect identification of a military pilot with international implications

The case is reported of a military pilot shot down in 1986 during a mission whose body was recovered in an advanced state of decomposition and delivered to Italian police in 1989. The first autopsy led to an incorrect identification of the corpse. Because of the advanced decomposed state of the corpse, a correct identification was made only through evaluation of the dental status and radiological examination. The correct evaluation of the specific shape of the amalgam restorations, particularly of those of the first and second inferior right molars, showed agreement with those of the pilot of the plane and not of the co-pilot as was initially stated. Received: 26 April 1996 / Received in revised form: 21 January 1997     

Fractal analysis of the trabecular bone pattern in the presence/absence of metal artifact–producing objects: Comparison of cone-beam computed tomography with panoramic and periapical radiography

Objectives:The effect of metallic objects on the fractal dimension (FD), bone area fraction (BAF) and gray scale values (GSVs) of cone-beam CT (CBCT) images was assessed. Also, FD, BAF and GSV were compared among CBCT, digital periapical and panoramic radiographies.Methods:Digital periapical and panoramic radiographs were acquired from six blocks of bovine rib. Additionally, different arrangements of titanium implants and intracanal metallic posts were created in the bone blocks and CBCT scans were taken from the different implant-root arrangements. The three radiographical modalities were compared by analysis of variance. Pairwise comparisons between the modalities were performed by the Tukey test (significance level set at 0.05).Results:Different root-implant arrangements in the CBCT images revealed no significant differences in the FD (p = 0.920), BAF and GSV values (p = 0.623). FD differed significantly among the three modalities (p < 0.001). Significant differences were found between CBCT and each of the periapical and panoramic techniques (p < 0.001), while no remarkable differences were observed in the FD of the periapical and panoramic images (p = 0.294). BAF and GSV showed significantly different results among the three radiographical techniques (p < 0.001). The difference was remarkable between CBCT and periapical (p < 0.001), CBCT and panoramic (p < 0.001) and periapical and panoramic (p = 0.008).Conclusion:Presence of titanium implants and intracanal posts does not produce different results in the fractal analysis (FA) of the CBCT images. The trabecular bone pattern is best assessed by FA of the periapical radiographs followed by the panoramic and CBCT techniques, respectively.     

The influence of liquid crystal display monitors on observer performance for the detection of interstitial lung markings on both storage phosphor and flat-panel-detector chest radiography

Purpose

To compare observer performance with a flat-panel liquid crystal display (LCD) monitor and with a high-resolution gray-scale cathode ray tube (CRT) monitor in the detection of interstitial lung markings using a silicon flat-panel-detector direct radiography (DR) and storage phosphor computed radiography (CR) in a clinical setting.

Materials and methods

We displayed 39 sets of posteroanterior chest radiographs from the patients who were suspected of interstitial lung disease. Each sets consisted of DR, CR and thin-section CT as the reference standard. Image identities were masked, randomly sorted, and displayed on both five mega pixel (2048 × 2560 × 8 bits) LCD and CRT monitors. Ten radiologists independently rated their confidence in detection for the presence of linear opacities in the four fields of the lungs; right upper, left upper, right lower, and left lower quadrant. Performance of a total 6240 (39 sets × 2 detector systems × 2 monitor system × 4 fields × 10 observers) observations was analyzed by multi-reader multi-case receiver operating characteristic (ROC) analysis. Differences between monitor systems in combinations of detector systems were compared using ANOVA and paired-samples t-test.

Results

Area under curves (AUC) for the presence of linear opacities measured by ROC analysis was higher on the LCDs than CRTs without statistical significance (p = 0.082). AUC was significantly higher on the DR systems than CR systems (p = 0.006). AUC was significantly higher on the LCDs than CRTs for DR systems (p = 0.039) but not different for CR systems (p = 0.301).

Conclusion

In clinical conditions, performance of the LCD monitor appears to be better for detecting interstitial lung markings when interfaced with DR systems.     

Rating the extent of surface scratches on photostimulable storage phosphor plates in a dental school environment

Objective

The aims of this study were (1) to subjectively quantify the degree of scratching and smudging that had taken place in the junior clinic in the 9 months following the implementation of digital radiology; (2) to compare the findings with a previously published report; and (3) to identify areas in the protocol and training that can be refined to minimize future scratching and smudging.

Methods

Seven sets of blank clinical photostimulable storage phosphor (PSP) plates were scanned after exposing them at 65 kV and 7 mA for 0.80 s. Scanned plates were lightly wiped with a soft cloth and alcohol, repackaged in plastic sleeves, re-exposed and rescanned. The two sets of resulting images were subjectively rated independently by two investigators for artefacts and placed in five categories.

Results

Of all the images, approximately 75% were rated in the top 3 categories (most readable), leaving 17% and 8% in the poor and unsatisfactory categories, respectively. Mean rated values of the two image sets (before and after wiping) were not statistically different, but ratings slightly improved after cleaning the plates.

Conclusions

Wiping all plates to remove surface contamination may not always be necessary or desirable. Systems that are designed to minimize handling of the plates may help minimize scratching of them.     

Digital skeletal radiography : Reduction of absorbed dose by adaptation of exposure factors and image processing

Purpose: The possibility to reduce the absorbed dose to the patient by increase of tube potential while maintaining the same exposure to the image plate and sufficient image quality in skeletal radiography has been investigated.Material and Methods: Image processing parameters were adjusted to account for an increase in tube potential by 20 kV. Revision of image processing parameters was based on measurements with phantoms constructed to simulate the histogram shape recorded for clinical images. Image quality was evaluated both using image quality criteria and visual grading analysis. Energy imparted was calculated from measurement of the kerma-area-product.Results and Conclusion: Energy imparted was reduced by 20-30% using the modified technique with increased kV. All images were considered of accurate quality for diagnosis and the difference in image quality score was marginal. There was, however, a significant shift towards lower grades for the "high kV" technique using visual grading analysis.     

平板DSA低剂量模式在冠状动脉造影术中的应用价值

目的 探讨平板探测器数字减影血管造影系统(DSA)低剂量模式在冠状动脉造影术中的应用价值.方法 选取住院拟行冠状动脉造影术患者60例,均为体重50 ～ 70 kg正常体型,随机分为低剂量模式组30例与常规对照组30例.术后由2位心内科介入治疗医师采用双盲法对所有图像进行评分.分别对两组患者的辐射剂量面积(DAP)、累积...     

利用数字摄影装置行头颅特殊体位摄影

目的：讨论利用数字摄影装置作头颅特殊体位摄影的可行性。方法：通过数字摄影装置对头颅特殊体位(如许氏位、梅氏位)成像效果的分析,指出在常规X线摄影中获取一些特殊体位的简单方法。结果：对于较复杂的头颅特殊体位可将被摄部位作为主体,而不必考虑更多的因素(如头颅的头颅指数、角度的大小)．进行体位设计．能更直观的一次性成像,成功率为98．69％,符合诊断要求。结论：此法与常规许、梅氏位显示方法所获得的图像显示效果相同．操作较简便,易于掌握。     

A preliminary investigation of the imaging performance of photostimulable phosphor computed radiography using a new design of mammographic quality control test object.

Leeds Test Object TOR[MAM] has been designed to supplement the current FAXIL mammography test object TOR[MAX]. It contains a range of details that have a more natural radiographic appearance and has been designed as a test that more closely approximates the image quality achieved in clinical mammography. Physical aspects of the design and implementation of TOR[MAM] are presented. The TOR[MAM] has been used in a preliminary physical evaluation of the comparative image qualities produced by conventional (screen-film) and photostimulable phosphor computed mammography and the results are discussed. TOR[MAX] results are also presented. The influence of digital image processing (enhancement) on the image quality of computed mammograms is also considered. The results presented indicate the sensitivity of TOR[MAM].     

软组织内非金属异物使用乳腺X线机的临床应用

目的：探讨使用乳腺X线机在发现软组织内非金属异物中的应用价值。方法：用猪肉代替人体软组织,将玻璃、陶瓷、混凝土,木棍作为非金属异物实验材料。首先对实验用的猪肉行乳腺X线机及常规X线机摄影,得到无异物的软组织X线片。然后把上述实验用的每一种材料按照大小不同分为三组,分别放入猪肉软组织内,逐一进行乳腺X线机和常规X线机摄影,每一种软组织中的异物得出两组X线图像,并对两组X线图像进行对比分析。结果：乳腺X线机与常规X线机对软组织内玻璃、陶瓷,混凝土异物显示情况比较：当异物最大径≥5 mm时,乳腺X线机与常规X线机摄影都显示清楚;当异物大小为2-5 mm时,乳腺X线机对三者显示均清楚,常规X线机对玻璃、陶瓷显示模糊,对混凝土显示清楚;当异物大小≤2 mm时,乳腺X线机对三者显示均清楚,常规X线机对玻璃、陶瓷不能显示,对混凝土显示模糊。乳腺X线机和常规X线机对木棍都不能显示。结论：在显示软组织内非金属异物时,乳腺X线机摄影较常规X线机摄影显示清楚,异物越小,乳腺X线机较常规X线机的优势越显著。     

Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography

Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024x1536x8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For "mass" depiction, interobserver agreement using CR was significantly lower than when using screen-film ( p<0.05). There was no significant difference in the kappa value for detecting "microcalcification"; however, the performance score of "microcalcification" on CR hard-copy was significantly lower than on the other three viewing methods ( p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms.     

Radiation dose of digital tomosynthesis for sinonasal examination: comparison with multi-detector CT

Objective

Using an anthropomorphic phantom, we have investigated the feasibility of digital tomosynthesis (DT) of flat-panel detector (FPD) radiography to reduce radiation dose for sinonasal examination compared to multi-detector computed tomography (MDCT).

Materials and methods

A female Rando phantom was scanned covering frontal to maxillary sinus using the clinically routine protocol by both 64-detector CT (120 kV, 200 mA s, and 1.375-pitch) and DT radiography (80 kV, 1.0 mA s per projection, 60 projections, 40° sweep, and posterior–anterior projections). Glass dosimeters were used to measure the radiation dose to internal organs including the thyroid gland, brain, submandibular gland, and the surface dose at various sites including the eyes during those scans. We compared the radiation dose to those anatomies between both modalities.

Results

In DT radiography, the doses of the thyroid gland, brain, submandibular gland, skin, and eyes were 230 ± 90 μGy, 1770 ± 560 μGy, 1400 ± 80 μGy, 1160 ± 2100 μGy, and 112 ± 6 μGy, respectively. These doses were reduced to approximately 1/5, 1/8, 1/12, 1/17, and 1/290 of the respective MDCT dose.

Conclusion

For sinonasal examinations, DT radiography enables dramatic reduction in radiation exposure and dose to the head and neck region, particularly to the lens of the eye.