Coronal plane stability of cruciate-retaining total knee arthroplasty in valgus gonarthrosis patients:A mid-term evaluation using stress radiographs

BACKGROUND Total knee arthroplasty(TKA)using implants with a high level of constraint has generally been recommended for patients with osteoarthritis(OA)who have valgus alignment.However,studies have reported favorable outcomes even with cruciate-retaining(CR)implants.AIM To evaluate the coronal plane stability of CR-TKA in patients with valgus OA at the mid-term follow-up.METHODS Patients with primary valgus OA of the knee who underwent TKA from January 2014 to January 2021 were evaluated through stress radiography using a digital stress device with 100 N of force on both the medial and lateral side.Gap openings and degrees of angulation change were determined.Descriptive statistical analysis was performed for both continuous and categorical variables.Inter-rater reliability of the radiographic measurements was evaluated using Cronbach’s alpha.RESULTS This study included 25 patients(28 knees)with a mean preoperative mechanical valgus axis of 11.3(3.6-27.3)degrees.The mean follow-up duration was 3.4(1.04-7.4)years.Stress radiographs showed a median varus and valgus gap opening of 1.6(IQR 0.6-3.0)mm and 1.7(IQR 1.3-2.3)mm and varus and valgus angulation changes of 2.5(IQR 1.3-4.8)degrees and 2.3(IQR 2.0-3.6)degrees,respectively.No clinical signs of instability,implant loosening,or revision due to instability were observed throughout this case series.CONCLUSION The present study demonstrated that using CR-TKA for patients with valgus OA of the knee promoted excellent coronal plane stability.

A Method of Digitally Reconstructed Radiographs Based on Medical CT Images

A complete and detail method is described to get digitally reconstructed radiographs （DRRs）. Casting rays to traverse CT images, computing CT values of resample points by interpolation, then converting CT value to its attenuation coefficient by using simplified segment function. Finally, DRRs enhancement is made to get the better display of region of interest （ROI）, and a new way is adopted to adjust the customization coefficient. The experimental results show that the proposed method is effective in generating the satisfied DRRs.

Correlation of stress radiographs to injuries associated with lateral ankle instability

BACKGROUND Stress radiographs have demonstrated superior efficacy in the evaluation of ankle instability.AIM To determine if there is a degree of instability evidenced by stress radiographs that is associated with pathology concomitant with ankle ligamentous instability.METHODS A retrospective review of 87 consecutive patients aged 18-74 who had stress radiographs performed at a single institution between 2014 and 2020 was performed.These manual radiographic stress views were then correlated with magnetic resonance imaging and operative findings.RESULTS A statistically significant association was determined for the mean and median stress radiographic values and the presence of peroneal pathology(P=0.008 for tendonitis and P=0.020 for peroneal tendon tears).A significant inverse relationship was found between the presence of an osteochondral defect and increasing degrees of instability(P=0.043).CONCLUSION Although valuable in the clinical evaluation of ankle instability,stress radiographs are not an independent predictor of conditions associated with ankle in-stability.

Investigation of coronoid process hyperplasia using Levandoski analysis on panoramic radiographs

BACKGROUND The diagnosis of coronoid process hyperplasia(CPH)is usually based on symptoms and radiological imaging.Because of its similar symptoms,it can be confused with temporomandibular joint diseases.Therefore,an objective and reproducible way of diagnosis should be determined.AIM To investigate CPH using Levandoski analysis on panoramic radiographs to determine its prevalence.METHODS A total of 300 panoramic radiograph images(600 coronoid processes)were examined.Having measured the Condyle-Gonion(Cd-Go)and Coronoid-Gonion(Cor-Go)distances,the Cor-Go:Cd-Go ratio was calculated for the left and right sides of each image.RESULTS There was a statistically significant difference in Cd-Go and Cor-Go distances between male and female participants(P<0.001).There was no statistically significant relationship between Cor-Go:Cd-Go ratios and gender(P>0.05).CONCLUSION Cd-Go and Cor-Go distances were statistically significantly increased in males on both the left and right sides.The ratio of Cor-Go:Cd-Go was preserved in both genders.The prevalence of CPH was found to be 0.3%.

IMPROVED MARKING AND CHARACTERIZING OF PULMONARY NODULES ON DIGITAL RADIOGRAPHS USING A COMPUTER-AIDED DIAGNOSIS SYSTEM

Objective To evaluate and reduce inter-observer variations in the detection and characterization of pulmonary nodules on digital radiograph （DR） chest images. Methods Two hundreds and thirty-two new posterior-anterior DR chest images were collected from out-patient screening patients. Consensus was reached by two experienced radiologists on the marking, rating, and segmentation of small actionable nodules ranged from 5 to 15 mm in diameter using a computer-aided diagnosis （CAD） system. Both their own nodule findings and the computer＇s automatic nodule detection results were analyzed to make the consensus. Nodules identified together with corresponding likelihood rating and segmentation results were referred as ＂Gold Stand- ard＂. Two un-experienced radiologists were asked to first mark and characterize suspicious nodules independently, then were allowed to consult the computer nodule detection results and change their decisions. Results Large inter-observer variations in pulmonary nodule identification and characterization on DR chest images were observed between un-experienced radiologists. Un-expefienced radiologists could greatly benefit from the CAD system, including substantial decrease of inter-observer variation and improvement of nodule detection rates. Moreover, radiologists with different levels of skillfulness could achieve similar high level performance after using the CAD system. Conclusion The CAD system shows a high potential for providing a valuable assistance to the examination of DR chest images.

Development and Application of an Instrument for Analysis of Bone Structure on Radiographs

An instrument used for quantitative assessment of trabecular structure of radius on radiograph including trabecular number and trabecular width was developed using a microdensitometer and a single-chip microcomputer. The device is characterized by its high sensitivity, good reproducibility, convenience and economy. The results obtained with the instrument were significantly correlated to actual bone mineral content, This device can be used for the diagnosis of osteoporosis, fluorosis, rickets and bone damages caused by cadmium.

Lung cancer screening: Computed tomography or chest radiographs?

Worldwide, lung cancer is the leading cause of mortalitydue to malignancy. The vast majority of cases of lung cancer are smoking related and the most effective way of reducing lung cancer incidence and mortality is by smoking cessation. In the Western world, smoking cessation policies have met with limited success. The other major means of reducing lung cancer deaths is to diagnose cases at an earlier more treatable stage employing screening programmes using chest radiographs or low dose computed tomography. In many countries smoking is still on the increase, and the sheer scale of the problem limits the affordability of such screening programmes. This short review article will evaluate the current evidence and potential areas of research which may benefit policy making across the world.

Can immediate postoperative radiographs predict outcomes in pediatric clubfoot?

BACKGROUND The goal of treatment for pediatric idiopathic clubfoot is to enable the patient to comfortably walk on his or her soles without pain.However,currently accepted treatment protocols are not always successful.Based on the abnormal bone alignment reported in this disease,some studies have noted a correlation between radiographic characteristics and outcome,but this correlation remains debated.AIM To assess the correlation between immediately postoperative radiographic parameters and functional outcomes and to identify which best predicts functional outcome.METHODS To predict the outcome and prevent early failure of the Ponseti’s method,we used a simple radiographic method to predict outcome.Our study included newborns with idiopathic clubfoot treated with Ponseti’s protocol from November 2018 to August 2022.After Achilles tenotomy and a long leg cast were applied,the surgeon obtained a single lateral radiograph.Radiographic parameters included the tibiocalcaneal angle(TiCal),talocalcaneal angle(TaCal),talofirst metatarsal angle(Ta1st)and tibiotalar angle(TiTa).During the follow-up period,the Dimeglio score and functional score were examined 1 year after surgery.Additionally,recurring events were reported.The correlation between functional score and radiographic characteristics was analyzed using sample and multiple logistic regression,and the optimal predictor was also identified.RESULTS In total,54 feet received approximately 8 manipulations of casting and Achilles tenotomy at a mean age of 149 days.The average TiCal,TaCal,Ta1st,and TiTa angles were 75.24,28.96,7.61,and 107.31 degrees,respectively.After 12 mo of follow up,we found 66%excellent-to-good and 33.3%fair-to-poor functional outcomes.The Dimeglio score significantly worsened in the poor outcome group(P value<0.001).Tical and TaCal showed significant differences between each functional outcome(P value<0.05),and the TiCal strongly correlated with outcome,with a smaller angle indicating a better outcome,each 1 degree decrease improved the functional outcome by 10 percent.The diagnostic test revealed that a TiCal angle of 70 degrees predicts an inferior functional outcome.CONCLUSION The TiCal,derived from lateral radiographs immediately after Achilles tenotomy,can predict functional outcome at 1 year postoperatively,justifying its use for screening patients who need very close follow-up.

Clinical Applications of Successive Spot Radiographs in Esophagography for Diagnosing the Early Esophageal Cancer

Objective:To introduce primary experience of clinical applications of successive spot radiographs in esophagography for the diagnosis of early esophageal cancer(EEC). Methods: Six patients with EEC were examined and diagnosed by a digital X-ray machine.According to the routine double contrast study of esophagus,the patient gulped a barium suspension in the upright position when the successive films were taken by 2 frames per second lasting for about 10 seconds.Various phases were obtained including barium-filled views,mucosal relief views and double contrast views. Results: Functional changes and abnormal mucosal folds of esophagus were present on successive spot radiographs of esophagography in patients with EEC and those patients with EEC were confirmed by endoscopic and pathologic findings.Four patients had mild loss of distensibility,2 patients had spasmodic contraction and 1 patient had barium retention.Thickened or interrupted folds were found in all cases.Little niches were detected in 5 of 6 patients. Conclusion: Evidence presented in barium studies of esophagus is more comprehensive and intact for the diagnosis of EEC when successive spot radiographs are employed.Functional changes of esophagus are more evident with this approach.

A Method for Measurement of the Hypertrophic First Metatarsal Medial Eminence on Foot Radiographs—A Reliability Study with Surgical Implications

Background: It has been suggested that hypertrophic eminence on the medial head of the first metatarsal is a component of the patho-anatomy of hallux valgus. However, research findings in this area are inconsistent, possibly due to differences in methods in identifying and measuring the medial eminence. To date, reliability of any method of measurement has not been reported. The purpose of this study was to determine the reliability of measurement of the medial eminence on medial oblique and dorsoplantar radiographs using a previously described geometric technique. Methods: To evaluate the reliability of a method of measurement of the medial eminence of the first metatarsal duplicate standardized dorsoplantar and medial oblique radiographs were taken of one foot of 15 subjects. The feet included both rectus feet and subjects with hallux valgus. The medial eminence was measured on the digital images using Inteleviewer 2.5 (Intelerad medical systems incorporated, Montreal, Quebec) software. Observer 1 measured one randomly selected image from each subject to determine inter-observer reliability. Observer 2 measured all images to determine the overall intraobserver reliability. Reliability was calculated using intra-class correlation coefficients (ICC). Results: The mean projection of the medial eminence ranged from 0.39 to 0.44 cm in both views. The ICCs were calculated for the dorsoplantar view and the 2 medial oblique view measures between observers. They ranged from 0.76 intra-rater and 0.86 interrater in the dorsoplantar view to 0.80 intra-rater and 0.90 inter-rater in the medial oblique view indicating good reliability in all measures. The average of the 4 oblique views also showed a high level of reliability with a coefficient of 0.96. Conclusions: The medial eminence can be reliably measured in the medial oblique and dorsoplantar view using the described technique. The medial oblique and the dorsoplantar views are valuable and reliable projections for visualising the dorso medial aspect of the first metatarsal.

Transformer-Based Deep Learning Network for Tooth Segmentation on Panoramic Radiographs

Panoramic radiographs can assist dentist to quickly evaluate patients’overall oral health status.The accurate detection and localization of tooth tissue on panoramic radiographs is the first step to identify pathology,and also plays a key role in an automatic diagnosis system.However,the evaluation of panoramic radiographs depends on the clinical experience and knowledge of dentist,while the interpretation of panoramic radiographs might lead misdiagnosis.Therefore,it is of great significance to use artificial intelligence to segment teeth on panoramic radiographs.In this study,SWin-Unet,the transformer-based Ushaped encoder-decoder architecture with skip-connections,is introduced to perform panoramic radiograph segmentation.To well evaluate the tooth segmentation performance of SWin-Unet,the PLAGH-BH dataset is introduced for the research purpose.The performance is evaluated by F1 score,mean intersection and Union(IoU)and Acc,Compared with U-Net,Link-Net and FPN baselines,SWin-Unet performs much better in PLAGH-BH tooth segmentation dataset.These results indicate that SWin-Unet is more feasible on panoramic radiograph segmentation,and is valuable for the potential clinical application.

Two-stage corrective operation for the treatment of pes cavovarus in patients with spina bifida

BACKGROUND Pes cavovarus has an estimated incidence of 8%-17%in patients with spina bifida(SB).The majority of the current literature on surgical treatment of cavovarus feet in children and adolescents includes a variety of diagnoses.There are currently no case series describing a treatment algorithm for deformity correction in this specific patient population.The authors of this study present the results of a retrospective case series performed to assess the radiographic outcomes of two-stage corrective surgery in patients with SB.METHODS Retrospective chart review was performed on patients with SB with a diagnosis of pes cavovarus at a freestanding children’s hospital who underwent surgical correction of the deformity.Patients were excluded for lack of two-stage corrective operation,nonambulatory status,lack of at least six months follow-up,and age>18 years at the time of surgery.This resulted in a cohort of 19 patients.Radiographic analysis was performed on 11 feet that had a complete series of preoperative and postoperative weightbearing X-rays.Preoperative and postoperative radiographic outcome measurements were compared using a two-sample t-test.RESULTS Significant changes between the preoperative and postoperative measurements were seen in Meary’s angle,the anteroposterior talo-first metatarsal(AP TMT1)angle,and the talonavicular coverage.Mean values of Meary’s angle were 17.9±13.1 preoperatively and 4.7±10.3 postoperatively(P=0.016).Mean AP TMT1 angle was 20.6±15.1 preoperatively and 9.3±5.5 postoperatively(P=0.011).Mean talonavicular coverage values were-10.3±9.6 preoperatively and-3.8±10.1 postoperatively(P=0.025).CONCLUSION The two-stage corrective procedure demonstrated efficacy in correcting cavovarus deformity in patients with SB.Providers should strongly consider employing the staged surgical algorithm presented in this manuscript for management of these patients.

HIPPO artificial intelligence:Correlating automated radiographic femoroacetabular measurements with patient-reported outcomes in developmental hip dysplasia

BACKGROUND Hip dysplasia(HD)is characterized by insufficient acetabular coverage of the femoral head,leading to a predisposition for osteoarthritis.While radiographic measurements such as the lateral center edge angle(LCEA)and Tönnis angle are essential in evaluating HD severity,patient-reported outcome measures(PROMs)offer insights into the subjective health impact on patients.AIM To investigate the correlations between machine-learning automated and manual radiographic measurements of HD and PROMs with the hypothesis that artificial intelligence(AI)-generated HD measurements indicating less severe dysplasia correlate with better PROMs.METHODS Retrospective study evaluating 256 hips from 130 HD patients from a hip preservation clinic database.Manual and AI-derived radiographic measurements were collected and PROMs such as the Harris hip score(HHS),international hip outcome tool(iHOT-12),short form(SF)12(SF-12),and Visual Analogue Scale of the European Quality of Life Group survey were correlated using Spearman's rank-order correlation.RESULTS The median patient age was 28.6 years(range 15.7-62.3 years)with 82.3%of patients being women and 17.7%being men.The median interpretation time for manual readers and AI ranged between 4-12 minutes per patient and 31 seconds,respectively.Manual measurements exhibited weak correlations with HHS,including LCEA(r=0.18)and Tönnis angle(r=-0.24).AI-derived metrics showed similar weak correlations,with the most significant being Caput-Collum-Diaphyseal(CCD)with iHOT-12 at r=-0.25(P=0.042)and CCD with SF-12 at r=0.25(P=0.048).Other measured correlations were not significant(P>0.05).CONCLUSION This study suggests AI can aid in HD assessment,but weak PROM correlations highlight their continued importance in predicting subjective health and outcomes,complementing AI-derived measurements in HD management.

Radiographic Equipment and Accessories as a Potential Source of Nosocomial Infection

Background: Nosocomial infections have become a major challenge in healthcare facilities as they affect the quality of medical care. Radiological imaging plays a crucial role in medical diagnosis. However, the equipment and accessories used increase the risk of transmission of nosocomial bacteria. Objective: This study aims to reveal the extent and nature of microbiological contamination in four hospital diagnostic imaging departments to determine their potential role in the spread of nosocomial bacteria and to evaluate the effectiveness of routine daily disinfection practices in controlling microorganisms in diagnostic imaging departments. Methods & Results: In each department, swabs were taken from the surfaces of selected parts of the equipment and accessories three times a day (early morning, noon, and evening) for five consecutive days. Bacteria were isolated from 65 swabs (36.1% of all samples). The bacteria were isolated 3 times (4.6%) in the morning, 16 times (24.6%) at midday, and 46 times (70.7%) in the evening. The bacteria isolated were Escherichia coli (isolated 34 times;52.3%), Staphylococcus aureus (20 times;30.8%), Staphylococcus epidermidis (6 times;9.3%), and Klebsiella species (5 times;7.7%). Discussion & Conclusion: Findings demonstrated that radiology equipment and accessories are not free of bacteria and further improvements in the sterilization and disinfection of radiology equipment and accessories are needed to protect staff and patients from nosocomial infections.

A Study on Extension－Flexion Dynamic Lumbar Spine Radiographsin Patients with Lumbar Intervertebral Disc Herniation

The study has collected a set of clinical materials such as extension-flexion dynamic lum-bar spine radiographs and computerized x-ray tornography of lumbar spine and quantified physical exami-nation from 32 patients with lumbar intervertebral disc herniation, who had gone through a suocessful con-servative treatment. The collection was conducted twice before and after the treatment. With the help oft-test and linear correlation analysis, the study suggests that extensionflexion radiograph of lumbar spineis of important clinical significance in weighing the clinical state of an individual patient, especially forthose who receive conservative treatment. The study emphasizes that the biomechanical disturbance oflumbar spinal column may be from another important pathological element along with the irritation of thenerve root by herniated disc tissue in the pathomechanics of lumbar disc herniation. There is also somediscussion of the computerized X-ray tomography diagnosis in this study. Above all, the author provides anew angle of viewing the trouble by one of the soul principles of traditional Chinese medicine: concept ofholistics .

Occult Andersson lesions in patients with ankylosing spondylitis: undetectable destructive lesions on plain radiographs

Background:Andersson lesions(ALs)are not uncommon in ankylosing spondylitis(AS).Plain radiography(PR)is widely used for the diagnosis of ALs.However,in our practice,there were some ALs in AS patients that could not be detected on plain radiographs.This study aimed to propose the concept of occult ALs and evaluate the prevalence and radiographic characteristics of the occult ALs in AS patients.Methods:A total of 496 consecutive AS patients were admitted in the Affiliated Drum Tower Hospital,Medical School of Nanjing University between April 2003 and November 2019 and they were retrospectively reviewed.The AS patients with ALs who met the following criteria were included for the investigation of occult ALs:(1)with pre-operative plain radiographs of the whole-spine and(2)availability of pre-operative computed tomography(CT)and/or magnetic resonance imaging(MRI)of the whole-spine.The occult ALs were defined as the ALs which were undetectable on plain radiographs but could be detected by CT and/or MRI.The extensive ALs involved the whole discovertebral junction or manifested as destructive lesions throughout the vertebral body.Independent-samples t test was used to compare the age between the patients with only occult ALs and those with only detectable ALs.Chi-square or Fisher exact test was applied to compare the types,distribution,and radiographic characteristics between detectable and occult ALs as appropriate.Results:Ninety-two AS patients with a mean age of 44.4±10.1 years were included for the investigation of occult ALs.Twenty-three patients had occult ALs and the incidence was 25%(23/92).Fifteen extensive ALs were occult,and the proportion of extensive ALs was significantly higher in detectable ALs(97%vs.44%,χ^(2)=43.66,P<0.001).As assessed by PR,the proportions of osteolytic destruction with reactive sclerosis(0 vs.100%,χ^(2)=111.00,P<0.001),angular kyphosis of the affected discovertebral units or vertebral body(0 vs.22%,χ^(2)=8.86,P=0.003),formation of an osseous bridge at the intervertebral space adjacent to ALs caused by the ossification of the anterior longitudinal ligament(38%vs.86%,χ^(2)=25.91,P<0.001),and an abnormal height of the affected intervertebral space were all significantly lower in occult ALs(9%vs.84%,χ^(2)=60.41,P<0.001).Conclusions:Occult ALs presented with more subtle radiographic changes.Occult ALs should not be neglected,especially in the case of extensive occult ALs,because the stability of the spine might be severely impaired by these lesions.

Deformable Registration of Chest Radiographs Using B-spline Based Method with Modified Residual Complexity

Accurate registration of chest radiographs plays an increasingly important role in medical applications.However, most current intensity-based registration methods rely on the assumption of intensity conservation that is not suitable for alignment of chest radiographs. In this study, we propose a novel algorithm to match chest radiographs, for which the conventional residual complexity(RC) is modified as the similarity measure and the cubic B-spline transformation is adopted for displacement estimation. The modified similarity measure is allowed to incorporate the neighborhood influence into variation of intensity in a justified manner of the weight, while the transformation is implemented with a registration framework of pyramid structure. The results show that the proposed algorithm is more accurate in registration of chest radiographs, compared with some widely used methods such as the sum-of-squared-differences(SSD), correlation coefficient(CC) and mutual information(MI)algorithms, as well as the conventional RC approaches.

Algorithm fusion to improve detection of lung cancer on chest radiographs

Purpose-The purpose of this paper is to show an efficient method for the detection of signs of early lung cancer.Various image processing algorithms are presented for different types of lesions,and a scheme is proposed for the combination of results.Design/methodology/approach-A computer aided detection(CAD)scheme was developed for detection of lung cancer.It enables different lesion enhancer algorithms,sensitive to specific lesion subtypes,to be used simultaneously.Three image processing algorithms are presented for the detection of small nodules,large ones,and infiltrated areas.The outputs are merged,the false detection rate is reduced with four separated support vector machine(SVM)classifiers.The classifier input comes from a feature selection algorithm selecting from various textural and geometric features.A total of 761 images were used for testing,including the database of the Japanese Society of Radiological Technology(JSRT).Findings-The fusion of algorithms reduced false positives on average by 0.6 per image,while the sensitivity remained 80 per cent.On the JSRT database the system managed to find 60.2 per cent of lesions at an average of 2.0 false positives per image.The effect of using different result evaluation criteria was tested and a difference as high as 4 percentage points in sensitivity was measured.The system was compared to other published methods.Originality/value-The study described in the paper proves the usefulness of lesion enhancement decomposition,while proposing a scheme for the fusion of algorithms.Furthermore,a new algorithm is introduced for the detection of infiltrated areas,possible signs of lung cancer,neglected by previous solutions.

Transfer learning-based super-resolution in panoramic models for predicting mandibular third molar extraction difficulty: a multi-center study

Background:This study aims to predict the extraction difficulty of mandibular third molars based on panoramic images using transfer learning while employing super-resolution(SR)technology to enhance the feasibility and validity of the prediction.Methods:We reviewed a total of 608 preoperative mandibular third molar panoramic radiographs from two medical facilities:the First Affiliated Hospital of Zhengzhou University(n=509;456 in the training set and 53 in the test set)and the Henan Provincial Dental Hospital(n=99 in the validation set).We conducted a deep-transfer learning network on high-resolution(HR)panoramic radiographs to improve the longitudinal resolution of the images and obtained the SR images.Subsequently,we constructed models named Model-HR and Model-SR using high-dimensional quantitative features extracted through the Least Absolute Shrinkage and Selection Operator method.The models’performances were evaluated using the receiver operating characteristic curve(ROC).To assess the reliability of the model,we compared the results from the test set with those of three dentists.Results:Model-SR outperformed Model-HR(area under the curve(AUC):0.779,sensitivity:85.5%,specificity:60.9%,and accuracy:79.8%vs.AUC:0.753,sensitivity:73.7%,specificity:73.9%,and accuracy:73.7%)in predicting the difficulty of extracting mandibular third molars.Both Model-HR(AUC=0.821,95%CI 0.687–0.956)and Model-SR(AUC=0.963,95%CI 0.921–0.999)demonstrated superior performance compared to expert dentists(highest AUC=0.799,95%CI 0.671–0.927).Conclusions:Model-SR yielded superior predictive performance in determining the difficulty of extracting mandibular third molars when compared with Model-HR and expert dentists’visual assessments.

Non-invasive optical characterization and estimation of Zn porosity in gas tungsten arc welding of Fe–Al joints using CR model and OES measurements

In this study,we employed a non-invasive approach based on the collisional radiative(CR)model and optical emission spectroscopy(OES)measurements for the characterization of gas tungsten arc welding(GTAW)discharge and quantification of Zn-induced porosity during the GTAW process of Fe–Al joints.The OES measurements were recorded as a function of weld current,welding speed,and input waveform.The OES measurements revealed significant line emissions from Zn-I in 460–640 nm and Ar-I in 680–800 nm wavelength ranges in all experimental settings.The OES coupled CR model approach for Zn-I line emission enabled the simultaneous determination of both essential discharge parameters i.e.electron temperature and electron density.Further,these predictions were used to estimate the Zn-induced porosity using OES-actinometry on Zn-I emission lines using Ar as actinometer gas.The OES-actinometry results were in good agreement with porosity data derived from an independent approach,i.e.x-ray radiography images.The current study shows that OES-based techniques can provide an efficient route for real-time monitoring of weld quality and estimate porosity during the GTAW process of dissimilar metal joints.