Radiographic Grid Research Articles

Radiographic grid for locating foreign bodies in maxillofacial emergency trauma

ObjectivesThe accurate localization of the foreign bodies (FBs) is essential. This work presents a new noninvasive technique for subcutaneous metallic FBs under a radiographic grid, a system that simplifies the localization of facial FBs removal using a grid with embedded reference points.MethodsThis work designed a retrospective study to evaluate the effect of a radiographic grid on FBs removal surgery. All patients who met the inclusion criteria and attended the Hospital of Stomatology of China Medical University from January 2022 to June 2023 were enrolled and randomly divided into grid and non-grid groups. The assessment of facial swelling, the primary indicator, was conducted on days 2 and 7 post-surgery. The variables were analyzed using the Student t test and a repeated-measures general linear model.ResultsThe study sample consisted of 20 patients, with 14 males (70%) and 6 females (30%), who had an average age of 30.30 ± 5.38. The average time of operation was 1.85 ± 0.66 h (range 0.7 to 3.2). In the present cases in this report, of the 20 patients’ FBs, 14 were metal, 5 were glass, and 1 was residual root. And the FBs were surgically removed with no postoperative complications. Through comparison, it was found that the degree of swelling on day 2 postoperatively was significantly different between the grid group and the non-grid group (P < 0.05).ConclusionsThis study demonstrates that a radiographic grid with mark points is a more efficient approach compared with traditional methods for FBs removal, and this surgical method is more accurate, fast and noninvasive.

Optimisation of pelvic imaging radiography protocols in plain radiology: a scoping review

Introduction: The purpose of this work is to explore which studies have been performed in the field of radiation dose reduction in pelvic x-ray imaging and to determine optimization techniques for dose reduction.Materials and methods: A scoping review was performed by using databases Science Direct, PubMed, EBSCO Host and Springer Link. The keywords used were "radiography", "dose reduction", "pelvis" and "pelvic". Exclusion criteria were the keywords "CT" and "MRI".Results: 15 scientific articles that analyse the current dose impacts in selected institutions or regions were reviewed as a starting point to optimise protocols, to establish diagnostic reference levels, or to suggest different measures for dose reduction. Studies suggest the use of digital image receptor, adaptation of exposure parameters; they also point out the use of air gap instead of radiographic grid and investigate the usefulness of the gonad protection. A difference was noticed in developing countries that focus more on the establishment of DRLs and following the guidelines provided by other countries rather than developing new dose optimisation techniques.Conclusion: A pelvic x-ray must be performed with a low radiation dose impact that still doesn't compromise the diagnostic value of the image, which can be achieved by following the ALARA principle and with certain adjustments, suggested by the considered studies, especially with exposure parameters. The establishment of national and local diagnostic reference levels is also required.

Use of mini implants for the two-implant retained mandibular overdenture: A prospective study

BackgroundThe two-implant retained mandibular overdenture utilizing nonsplinted implants is a proven treatment modality for completely edentulous patients. However, a lacuna still exists regarding the suitability of mini dental implants for this purpose. The purpose of the study was to evaluate implant stability and crestal bone loss in single-piece mini dental implants loaded with immediate or conventional loading protocols to retain a mandibular overdenture. MethodTwenty-four completely edentulous patients were rehabilitated using conventional maxillary complete denture and a mandibular two-implant retained overdenture utilizing nonsplinted single piece mini implants. The implants were loaded with immediate or conventional loading protocols. Implant stability (with Periotest TM) and crestal bone loss (with radiovisiograph and radiographic grid) were evaluated at the time of loading and at one, two, and six months after loading. Statistical analysis was done with the Independent Samples “t” test and One-Way ANOVA. ResultsMean Periotest Values observed were significantly more negative in implants loaded with the conventional loading protocol. Crestal bone loss was significantly lesser in the immediate loading protocol but was still higher than the requisite 1.5 mm postulated by established criteria. ConclusionTwo single-piece nonsplinted mini implants may be sufficient to retain a mandibular overdenture utilizing the immediate loading protocol. Further studies with a longer duration of observation and larger sample size are required.

A novel grid regression demodulation method for radiographic grid artifact correction.

In x-ray radiography, the commonly used antiscatter grid for enhancing image quality causes artifacts in the form of periodic noises, such as shadows, cutoff, and Moiré fringes. Software degridding is traditionally performed via linear or homomorphic filtering in the spectral domain. These methods inevitably result in image blurring, information loss, and distortion, thus hindering detection and assessment of diseases. We seek effective and practical solutions for grid artifact correction based on spatial-domain analysis toward high-quality imaging. By analyzing the physical process of grid artifact formation, we track down the root of the problem associated with spectral filtering. We propose the grid regression demodulation (GRD). The degridding cost is forged as a functional of the latent x-ray photon image and parametric grid model characterizing grid transmission property. Regularization on the grid spectra is incorporated. We devise optimization algorithms for artifact correction and grid pattern estimation. GRD decouples the partially overlapped spectra of the grid and anatomy, and removes the artifacts independently, thus restoring the underlying clinically relevant data. Method efficacy is demonstrated using simulated and real data. GRD effectively preserves image edges, textures, and patterns while removing grid artifacts. For the known ground truth setting, GRD gives a near-perfect correction. For real data, GRD is capable of correcting not only the primary grid artifacts, but also the higher grid harmonic artifacts while keeping image content unaltered, which is unachievable by the other methods. Our method has low residual errors and exhibits a successful demodulation effect without introducing additional artifacts, while ringing or cilia artifacts are present in the others. The proposed method outperforms the prevalent transform techniques for correcting grid artifacts in digital radiography. It is self-sustained and self-adaptive to a range of targets and beam quality. Our approach is advantageous in restoring the latent image while suppressing grid noises. It retrieves the true scale factor of the degridded data, which is unattainable via any spectral filtering techniques. This work unlocks a promising venue to improve and upgrade low-dose medical radiographic imaging technology.

Effect of grid geometry on the transmission properties of 2D grids for flat detectors in CBCT

To suppress scatter in cone beam computed tomography (CBCT), two-dimensional antiscatter grids (2D grid) have been recently proposed. In this work, we developed several grid prototypes with higher grid ratios and smaller grid pitches than previous designs, and quantified their primary and scatter transmission properties in the context of CBCT for radiation therapy.Three focused 2D grid prototypes were developed with grid ratios at 12 and 16, and grid pitches at 2 and 3 mm. Their scatter transmission properties were measured between 80–140 kVp, and benchmarked against a high performance radiographic grid (1D grid) using a Varian TrueBeam CBCT system. The effect of source–grid misalignment on the primary transmission and the improvement in contrast-to-noise ratio (CNR) were also evaluated.Changing the grid pitch from two to three mm increased the average primary transmission from 84% to 89%. Maximum scatter-to-primary ratio (SPR) with grid ratio of 12 was 0.3, and increasing the grid ratio to 16 reduced SPR by 30%. A 10 mm misalignment in 2D grid position led to a 6%–8% reduction in average primary transmission, and reduction was more pronounced for the higher grid ratio. 2D grids provided up to factor of seven lower SPR and 21% better primary transmission than the 1D grid, and their scatter transmission exhibited lower energy dependence. While 2D grids provided up to factor of 2.3 higher CNR improvement, a significant variation in CNR improvement was not observed among different grid pitch and ratios.In summary, grid ratio of 16 and grid pitch of 2 mm can keep SPRs below 0.2 even in high scatter conditions, while keeping primary transmission fractions above 80%, key benefits of the investigated 2D grids in improving image quality of CBCT. However, such grids require precise alignment in source-grid geometry during CBCT acquisitions. This study also implies that 2D grids can provide substantially better scatter suppression and primary transmission than high-performance 1D grids currently available.

Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques

Background: The success of various treatments protocols depends on pre-operative diagnostic aids such as radiographic assessment with linear measurements, in such scenario radiographic grid with its unique design aids like a scale for image analysis on intraoral periapical radiograph. Hence, the intra oral grid is a simple and accurate way of measuring objects, and another advantage is to overcome various magnification errors associated with measurements. So, the present study was designed to know its accuracy in assessing the linear measurements. Materials and Method: The study sample comprised a total of 40 subjects, which were categorized into four groups. A total of 240 exposures were taken, where each patient was subjected to six radiographs, of which two are conventional intraoral periapical radiographs without grid, and two are conventional intraoral periapical radiographs with grid by bisecting and paralleling technique and another two radiographs are taken by digital CMOS sensor with intraoral periapical grid in all four groups. The measurements were performed on the radiographs using scale and divider and in case of radiograph with the grid by counting the grid lines from specific points. Results: The results of the study revealed on comparison of conventional and digital radiographs with and without a grid in both bisecting and paralleling technique in all the four groups, there was a statistically significant difference noticed with digital radiography compared to the conventional method in assessing the measurements with the grid with P value

Comparison of Tentative Radiographic Working Length with and without grid Versus Electronic Apex Locator.

The apical termination of obturation is the most important factor influencing the success of root canal treatment (RCT). Working length (WL) is the key element in achieving this.Aim:The aim of this study is to compare and evaluate the preoperative estimated WL with conventional radiograph and with grid radiograph, with reference to electronic apex locator (EAL) in single-rooted teeth.Settings and Design:Thirty permanent anterior teeth with complete root formation indicated for RCT were included in this study.Materials and Methods:Conventional radiograph (Group 1) and conventional radiograph with external grid (Group 2) were made before access opening. WL with EAL (Group 3) was determined after access opening.Statistical Analysis:The statistical package for the social sciences (SPSS) version 16.0 (SPSS Inc., Chicago, IL, USA) was used to compare the WLs of three groups, and the statistical significance was considered to be P ≤ 0.05. ANOVA, post hoc test were made to measure the intergroup comparison, and Pearson correlation values were obtained.Results and Conclusion:The results of the study showed a higher correlation between grid WL and apex locator WL than conventional WL and apex locator WL. Preoperative metrics with radiographic grid along with the apex locator is a better measuring tool compared to the conventional radiographic WL in a single-rooted tooth.

Treatment of Non-Contained Infrabony Defects With Enamel Matrix Derivative Alone or in Combination With Biphasic Calcium Phosphate Bone Graft: A 12-Month Randomized Controlled Clinical Trial.

Use of enamel matrix derivative (EMD) when dealing with non-contained defects may be limited because EMD does not maintain a space itself. Use of combined therapy has been proposed, using a bone graft in combination with EMD to avoid collapse of the flap into the bony defect during healing time. Therefore, the aim of this study is to evaluate the clinical and radiologic healing response of non-contained infrabony defects after treatment with a combination of EMD and biphasic calcium phosphate (BC) or EMD alone. Fifty-two patients with at least one infrabony defect ≥3 mm in depth with a probing depth (PD) ≥6 mm were randomly treated with EMD/BC or EMD alone. Clinical and radiographic parameters were evaluated at baseline, 6, and 12 months after surgery. To standardize the procedure, an acrylic stent and millimeter radiographic grid were used. The primary outcome was the change in clinical attachment level (CAL). Analysis of the data demonstrated a statistically significant difference from baseline within each group (P <0.05), with a difference in clinical and radiographic parameters at 6 and 12 months. After 1 year, mean PD reductions of 3.14 ± 1.95 mm (39.6%) in the EMD/BC group and 3.30 ± 1.89 mm (48.7%) in the EMD group were achieved. A mean CAL gain of 2.38 ± 2.17 mm (24.9%) in the EMD/BC group and 2.65 ± 2.18 mm (36.2%) in the EMD group were obtained. Reduction in the infrabony component was 2.71 ± 1.79 mm (57.9%) in the test group and 2.60 ± 2.03 mm (28.5%) in the control group. There were no statistically significant differences between treatment groups. It was concluded that treatment of non-contained infrabony defects with EMD, with or without BC, resulted in statistically significantly better results after 12 months compared with baseline measurements. In contrast, the combined approach did not result in a statistically significant improvement.

Height and Depth Guidelines for Anatomic Femoral Tunnels in Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

To develop guidelines for femoral tunnel placement based on height and depth on the lateral wall of the notch and to apply these guidelines arthroscopically to show tunnel placements within the anterior cruciate ligament (ACL) femoral insertion site. Twelve cadaveric knees were dissected to define the centers of the femoral ACL attachment and its anteromedial (AM) and posterolateral (PL) bundles. In 90° of flexion, the height and depth of each center were determined relative to the low point on the lateral intercondylar notch. Radiographic grid measurements were made to validate these measurements. Subsequently, the measurement guidelines were applied arthroscopically in 10 new cadaveric knees to evaluate their accuracy for an anatomic single-bundle femoral tunnel. Interobserver reliability analysis was evaluated with the intraclass correlation coefficient. In 90° of flexion, the height of the ACL center was 8.7 ± 0.6mm from the low point of the lateral notch; PL center, 7.2 ± 1.2mm; and AM center, 9.6 ± 1.1mm. Relative to the low point, the ACL center was 1.7 ± 1.7mm posterior, the PL center was 3.4 ± 1.5mm anterior, and the AM center was 4.9 ± 1.7mm posterior (intraclass correlation coefficient, 0.859). Radiographic grid measurements were consistent with the direct measurements. Application of the guidelines arthroscopically with or without the assistance of a 7-mm offset aimer placed all guide pins for tunnels within the femoral ACL footprint, with 90% within 4mm of the ACL center. This study showed in cadaveric knees in 90° of flexion that the center of the ACL can be located on the lateral notch at a height of 8.7 ± 0.6mm from the lowest point and anterior 11.5 ± 1.3mm from the deepest point. How anatomic tunnels can be placed using these measurements was also shown in cadaveric knees. An anatomic femoral tunnel for ACL reconstruction can be placed using height and depth guidelines.

Assessment of bone-fill following regenerative periodontal therapy by image subtraction using commercially available software

Context: There are few applicable methods and scant literature on using non-specific image analysis software to assess and quantify post-periodontal surgery bone-fill. Aims: The present study describes the method of digital subtraction radiography (DSR) and morphometric area analysis (MA) in assessing bone-fill following regenerative periodontal therapy by using two image processing tools. Settings and Design: For the bone-fill assessment, radiographs of 78 angular bone defects from 30 subjects who underwent periodontal flap surgery with hydroxyapatite bone graft placement were utilized. Materials and Methods: The initial radiographic image obtained at baseline was subtracted from the radiographic images taken at 12/24 weeks by using the commercially available image processing software. After digital subtraction, the digitized and excluded interdental bone was transferred to open source software for area calculation. Bone-fill calculated by using DSR and MA was compared to the bone-fill values obtained by using the 1 mm 2 counting grid placed over the digital sensor. Statistical Analysis: Intragroup comparison of bone-fill between various groups was performed using repeated measures analysis of variance (ANOVA) followed by multiple comparisons using Bonferroni correction. One-way ANOVA followed by the post hoc test was used for intragroup and intergroup comparison. Results: DSR and MA showed higher mean bone-fill levels over radiographic grid. Conclusion: Considering that the software aims to reduce the inaccuracy behind manual assessment of bone-fill, the overestimation of bone-fill as compared to a grid may be attributed to the enhanced sensitivity of the method.

Elimination of gridlines by using non-linear filter in mammographic image

Mammographic X-ray equipment uses a radiographic grid to remove the scatter radiation and improve image contrast. The grid causes striped lines to appear on the film and may degrade diagnostic information. This study deals with the mechanism of the gridline appearance, the gridline image on the mammographic film, and a method for eliminating the gridlines. In this study, the background noise caused by the radiographic grid is investigated by using a one-dimensional Fourier transform and the characteristics of the gridlines on the X-ray film are clarified. In addition, a new method that reduces the background noise caused by the radiographic grid on mammographic film is proposed by using non-linear image filtering. To eliminate gridlines effectively, the region of the filter is considered and V-filtering and median filtering are performed as methods of image filtering. In an experiment using a breast phantom, a signal-to-noise ratio (SNR) in the microcalcification region is calculated. The SNR of the image processed by median filtering after the V-filtering is increased. The value of the power spectrum at a frequency that represents the periodic noise made by the gridlines is decreased. The validity of image filtering is confirmed. This proposed image-filtering method is found to be useful for eliminating gridlines in the X-ray image.

Radiographic griding of subcutaneous soft tissue metallic foreign bodies in emergency department

Radiographic grid for localization of soft tissue metallic foreign bodies is a modification of traditional radiography. Twenty localization procedures using simple radiographic grid was successfully performed. Its low cost and easy to perform makes it a useful tool in emergency setting.

Non-metallic grid for radiographic measurement

The purpose of this paper is to suggest an easier, non-metallic radiographic grid system for measuring the working length and radiographic size of pathologic areas during endodontic diagnosis and prognosis determination.

The Derivation of Reference Dose Values to Chest X Rays in Paediatric Radiography

Chest X rays are by far the most frequent radiological examination in paediatric patients. The purpose of this study was to select appropriate reference doses for four different age groups - premature infants, 10 month infants, 5 year old children and 10 year old children. Calculations were performed on dosimetric data based on four European-wide surveys. It is proposed that the mean values or the 3rd quartiles derived from the distribution of entrance surface dose values from radiology departments using 'optimised' techniques - with reference to radiographic voltage, grid use and screen-film combinations might be better suited as reference dose values than the previously recommended values which did not respect good radiographic technique adequately.

Performance of glass fiber antiscatter devices at mammographic energies.

Using fiber optic manufacturing techniques, it is possible to produce a radiographic grid that discriminates against scattered radiation in two dimensions. Such grids consist of septa composed of glass with a high lead content; the interspace material is air, so that approximately 80% of the grid area is open. In this way, effective high ratio grids can be produced with relatively low Bucky factors. The performance of samples of such grid material is characterized in terms of both scatter rejection and dose efficiency for application in digital mammography in both slot-beam and area-beam geometry. For area beams, five- to tenfold improved scatter rejection relative to conventional grids was observed. In slot configurations, such grids could provide improved SNR/dose performance and more effective utilization of the heat loading capability of the x-ray source.

Simple test pattern for mammographic screen-film contact measurement.

Test patterns to measure mammographic screen-film contact require the use of a much finer screen-wire mesh than can be used in test patterns for other diagnostic cassettes. The author has found that a radiographic grid of any line spacing equal to or exceeding 40 lines per inch can be used to test mammographic screen-film contact, making it unnecessary to purchase a special dedicated fine-mesh mammographic test pattern. However, the use of a magnification technique will often be required, since modern grids have mesh frequencies in excess of 100 lines per inch.

Incoherent Optical Quality Control Of Radiographic Grids

The radiographic grid is an array of high atomic number blades interleaved with relatively transparent ones. The radiograph of a grid is a grating having a square wave transmittance function. If two such radiographs are superposed in a convenient way and looked at on a film viewer, moire fringes appear. From visual inspection of the fringes several structural defects in the grid show up. Some pictures explain how to enhance line defects, frequency, and pulse width modulation defects, all of them being related to uneven thickness of the blades which form the grid. Other manufacturing defects, which do not affect the periodical structure and must therefore be detected by other test methods, are also discussed.