Accuracy of digital and analogue cephalometric measurements assessed with the sandwich technique

Reliability and accuracy of Artificial intelligence-based software for cephalometric diagnosis. A diagnostic study

BACKGROUND

Artificial intelligence (AI) is revolutionizing cephalometric diagnosis in orthodontics, streamlining the patient assessments. This study aimed to assess the reliability, accuracy, and time consumption of artificial intelligence (AI)-based software compared to a conventional digital cephalometric analysis method on 2D lateral cephalogram.

METHODS

408 lateral cephalometries were analysed using three methods: manual landmark localization, automatic localization, and semi-automatic localization with AI-based software. On each lateral cephalogram, 15 variables were selected, including skeletal, dental, and soft tissue measurements. The difference between the two AI-based software options (automatic and semi-automatic) was compared with the conventional digital technique. The time required to produce a complete cephalometric tracing was evaluated for each method using Student's t-test.

RESULTS

Statistically significant differences in the accuracy of landmark positioning were detected among the three different techniques (p < 0,01). However, it is noteworthy that almost all of these differences were not clinically significant. There was a small difference in accuracy between the semi-automatic AI-based option and conventional digital techniques. Regarding the time used for each technique, the automatic version was the fastest, followed by the semi-automatic option and the conventional digital technique. (p < 0,000).

CONCLUSIONS

The study showed a statistical difference in accuracy between the conventional digital technique and two AI-based software alternatives, but these differences were not clinically significant except for specific measurements. The semi-automatic option was more accurate than the automatic one and faster than conventional tracing. Further research is needed to confirm AI's accuracy in cephalometric tracing.

Comparison Between an Expert Operator an Inexperienced Operator, and Artificial Intelligence Software: A Brief Clinical Study of Cephalometric Diagnostic

INTRODUCTION

Artificial intelligence (AI) is constantly developing in several medical areas and has become useful to assist with treatment planning. Orthodontics and maxillofacial surgery use AI-based technology to identify and select cephalometric points for diagnostics. Although some studies have shown promising results from the use of AI, the evidence is still limited. Hence, additional investigation is justified.

MATERIALS AND METHODS

In this retrospective study, 2 human operators (1 expert and 1 inexperienced) and 1 software analyzed 30 lateral cephalograms of individuals with orthodontic treatment indications. They measured 10 cephalometric variables and then 2 weeks later, repeated measurements on 30% of the sample. We evaluated the reliability of the measurements between the 2-time points and the differences in the means between the expert operator and the AI software and between the expert and inexperienced operators.

RESULTS

There was high reliability for the expert operator and AI measurements, and moderate reliability for the inexperienced operator measurements. There were some significant differences in the means produced by the AI software and the inexperienced operator compared with the expert operator.

CONCLUSION

Although AI is useful for cephalometric analysis, it should be used with caution because there are differences compared with analysis by humans.

Accuracy of and dental students' preferences toward manual and digital cephalometric landmark identification: A randomized cross-over study

OBJECTIVE

To evaluate dental students' perceptions of manual and digital cephalometric landmark identification methods based on their preferences, difficulty level, and procedure time required to provide insights into the future of dental education, considering incorporating digital technology in dental schools.

MATERIALS AND METHODS

Fifty-five second-year dental students were randomly divided into two groups: (1) group A, students who performed manual landmark identification first, followed by digital method; and (2) group B, students who performed digital method first, followed by manual method. The duration of the procedure was recorded. Subsequently, all students completed a questionnaire regarding the difficulty they experienced using a visual analog scale and their preferences. Landmark identification accuracy was measured.

RESULTS

Digital landmark identification was preferred by 93% of students. The mean procedure time for digital method was significantly lower than that of manual method (13.00 ± 5.60 vs. 9.70 ± 4.60; p = 0.002). Group B completed manual and digital methods in a shorter time than group A. Group A experienced less difficulty with manual procedure than group B. However, statistically significant differences were not observed in the difficulty level of digital technique. A statistically significant difference in the mean accuracy was shown in favor of the manual method. However, this difference is clinically insignificant (p = 0.001).

CONCLUSIONS

Students considered digital method to be effective for learning and preferred it over manual method. Furthermore, digital landmark identification demonstrated better performance and was faster than manual method, suggesting that this must be incorporated in undergraduate dental education.

Reproducibility of Computerized Cephalometric Analysis Software Compared with Conventional Manual Tracing for Analyzing Skeletal Stability After Orthognathic Surgery

Objective

This study aimed to compare the difference between analyzing skeletal stability after orthognathic surgery by lateral cephalogram measurement created from Dolphin software (version 11.95) compared with the manual technique.

Methods

Twenty-eight patients who underwent mandibular setback surgery (BSSRO) were randomly selected between 2015 and 2021. Serial lateral cephalograms were analyzed at four different time sets postoperatively, and a total of 112 cephalometric radiographs were obtained. Horizontal measurement (BX), vertical measurement (BY), and 3 angular measurements (SNB, ANB, and Gonial angle) were analyzed by manual tracing and Dolphin software by 2 examiners. The intraclass correlation coefficient determined the intra-rater reliability. Parameter differences between timelines were observed for skeletal stability, and mean values between methods were compared using the Student's t-test.

Results

Both examiners were generally consistent in the repeated measurements (ICCs of the manual method ranged from 0.926 to 0.994, and the digital method ranged from 0.719 to 0.956). All variables represented skeletal stability at T0-T1, T0-T2, and T0-T3 showed no statistically significant differences between methods except ANB (T0-T1; p value = 0.009).

Conclusions

Computerized cephalometric analysis software is relatively reproducible for assessing skeletal changes after orthognathic surgery and can be used routinely in follow-up.

Ceph-Net: automatic detection of cephalometric landmarks on scanned lateral cephalograms from children and adolescents using an attention-based stacked regression network

BACKGROUND

The success of cephalometric analysis depends on the accurate detection of cephalometric landmarks on scanned lateral cephalograms. However, manual cephalometric analysis is time-consuming and can cause inter- and intra-observer variability. The purpose of this study was to automatically detect cephalometric landmarks on scanned lateral cephalograms with low contrast and resolution using an attention-based stacked regression network (Ceph-Net).

METHODS

The main body of Ceph-Net compromised stacked fully convolutional networks (FCN) which progressively refined the detection of cephalometric landmarks on each FCN. By embedding dual attention and multi-path convolution modules in Ceph-Net, the network learned local and global context and semantic relationships between cephalometric landmarks. Additionally, the intermediate deep supervision in each FCN further boosted the training stability and the detection performance of cephalometric landmarks.

RESULTS

Ceph-Net showed a superior detection performance in mean radial error and successful detection rate, including accuracy improvements in cephalometric landmark detection located in low-contrast soft tissues compared with other detection networks. Moreover, Ceph-Net presented superior detection performance on the test dataset split by age from 8 to 16 years old.

CONCLUSIONS

Ceph-Net demonstrated an automatic and superior detection of cephalometric landmarks by successfully learning local and global context and semantic relationships between cephalometric landmarks in scanned lateral cephalograms with low contrast and resolutions.

Assessment of the quality of different commercial providers using artificial intelligence for automated cephalometric analysis compared to human orthodontic experts

PURPOSE

The aim of this investigation was to evaluate the accuracy of various skeletal and dental cephalometric parameters as produced by different commercial providers that make use of artificial intelligence (AI)-assisted automated cephalometric analysis and to compare their quality to a gold standard established by orthodontic experts.

METHODS

Twelve experienced orthodontic examiners pinpointed 15 radiographic landmarks on a total of 50 cephalometric X‑rays. The landmarks were used to generate 9 parameters for orthodontic treatment planning. The "humans' gold standard" was defined by calculating the median value of all 12 human assessments for each parameter, which in turn served as reference values for comparisons with results given by four different commercial providers of automated cephalometric analyses (DentaliQ.ortho [CellmatiQ GmbH, Hamburg, Germany], WebCeph [AssembleCircle Corp, Seongnam-si, Korea], AudaxCeph [Audax d.o.o., Ljubljana, Slovenia], CephX [Orca Dental AI, Herzliya, Israel]). Repeated measures analysis of variances (ANOVAs) were calculated and Bland-Altman plots were generated for comparisons.

RESULTS

The results of the repeated measures ANOVAs indicated significant differences between the commercial providers' predictions and the humans' gold standard for all nine investigated parameters. However, the pairwise comparisons also demonstrate that there were major differences among the four commercial providers. While there were no significant mean differences between the values of DentaliQ.ortho and the humans' gold standard, the predictions of AudaxCeph showed significant deviations in seven out of nine parameters. Also, the Bland-Altman plots demonstrate that a reduced precision of AI predictions must be expected especially for values attributed to the inclination of the incisors.

CONCLUSION

Fully automated cephalometric analyses are promising in terms of timesaving and avoidance of individual human errors. At present, however, they should only be used under supervision of experienced clinicians.

Reproducibility of linear and angular cephalometric measurements obtained by an artificial-intelligence assisted software (WebCeph) in comparison with digital software (AutoCEPH) and manual tracing method

INTRODUCTION

It has been suggested that human errors during manual tracing of linear/angular cephalometric parameters can be eliminated by using computer-aided analysis. The landmarks, however, are located manually and the computer system completes the analysis. With the advent of Artificial Intelligence in the field of Dentistry, automatic location of the landmarks has become a promising tool in digital Orthodontics.

METHODS

Fifty pretreatment lateral cephalograms obtained from the Orthodontic department of SRM dental college (India) were used. Analysis were done by the same investigator using the following methods: WebCeph™, AutoCEPH© for Windows or manual tracing. Landmark identification was carried out automatically by Artificial Intelligence in WebCeph™ and with a mouse driven cursor in AutoCEPH©, and manually using acetate sheet and 0.3-mm pencil, ruler and a protractor. The mean differences of the cephalometric parameters obtained between the three methods were calculated using ANOVA with statistical significance set at p<0.05. Intraclass correlation coefficient (ICC) was used to determine both reproducibility and agreement between linear and angular measurements obtained from the three methods and intrarater reliability of repeated measurements. ICC value of >0.75 indicated good agreement.

RESULTS

Intraclass correlation coefficient between the three groups was >0.830, showing good level of agreement, and the value within each group was >0.950, indicating high intrarater reliability.

CONCLUSION

Artificial Intelligence assisted software showed good agreement with AutoCEPH© and manual tracing for all the cephalometric measurements.

Evaluation and comparison of smartphone application tracing, web based artificial intelligence tracing and conventional hand tracing methods

AIM

The aim of this study was to compare and evaluate the reliability of three different cephalometric assessment methods: Smartphone Application Tracing Method CephNinja (SATM), Web Based Artificial Intelligence (AI) Driven Tracing Method WebCeph (WATM) and Conventional Hand Tracing Method (CHTM).

METHODS

110 lateral cephalometric radiographs were enrolled in the study and 4 linear and 7 angular parameters were traced and measured by one examiner using CephNinja, WebCeph and conventional hand tracing methods. Independent-samples Kolmogorov-Smirnov and Shapiro Wilks tests were used to compare the mean values of intra-examiner differences. Both intra-method and inter-method correlations were evaluated.

RESULTS

There were statistically significant differences between the methods in terms of SNA (p:0.003; p < 0.05); SNB measurements (p:0.001; p < 0.05); SN-MP angle (p:0.001; p < 0.05); U1-SN angle (p:0.001; p < 0.05); L1-NB(mm) (p:0.007; p < 0.05) and E Line-Upper Lip(mm) measurements (p:0.013; p < 0.05). All intra-method correlation coefficients are 80% and above. In terms of inter-method coefficients the lowest coefficient of agreement is 0.170 and it is the coefficient of agreement between CHTM and SATM for measurement of U1-NA. The highest coefficient of agreement is 0.884 which is between WBTM and SATM for SNB measurement.

CONCLUSIONS

The null hypothesis was rejected. There were statistically and clinically significant differences in various measurements among groups.

Evaluation of fully automated cephalometric measurements obtained from web-based artificial intelligence driven platform

Background

Artificial Intelligence has created a huge impact in different areas of dentistry. Automated cephalometric analysis is one of the major applications of artificial intelligence in the field of orthodontics. Various automated cephalometric software have been developed which utilizes artificial intelligence and claim to be reliable. The purpose of this study was to compare the linear and angular cephalometric measurements obtained from web-based fully automated Artificial Intelligence (AI) driven platform “WebCeph”™ with that from manual tracing and evaluate the validity and reliability of automated cephalometric measurements obtained from “WebCeph”™.

Methods

Thirty pre-treatment lateral cephalograms of patients were randomly selected. For manual tracing, digital images of same cephalograms were printed using compatible X-ray printer. After calibration, a total of 18 landmarks was plotted and 12 measurements (8 angular and 4 linear) were obtained using standard protocols. The digital images of each cephalogram were uploaded to “WebCeph”™ server. After image calibration, the automated cephalometric measurements obtained through AI digitization were downloaded for each image. Intraclass correlation coefficient (ICC) was used to determine agreement between the measurements obtained from two methods. ICC value < 0.75 was considered as poor to moderate agreement while an ICC value between 0.75 and 0.90 was considered as good agreement. Agreement was rated as excellent when ICC value > 0.90 was obtained.

Results

All the measurements had ICC value above 0.75. A higher ICC value > 0.9 was obtained for seven parameters i.e. ANB, FMA, IMPA/L1 to MP (°), LL to E-line, L1 to NB (mm), L1 to NB (°), S-N to Go-Gn whereas five parameters i.e. UL to E-line, U1 to NA (mm), SNA, SNB, U1 to NA (°) showed ICC value between 0.75 and 0.90.

Conclusion

A good agreement was found between the cephalometric measurements obtained from “WebCeph”™ and manual tracing.

Influence of Orthodontist’s Gender and Experience on the Perception of Dentoskeletal Parameters Using Cephalometric Radiographs: A Questionnaire Study

AIM: The aim of the study was to evaluate the influence of orthodontist’s gender and experience on the perception of dentoskeletal parameters through cephalometric radiographs. METHODS:An online survey was developed using six laterals cephalometric radiographs. The survey included questions about clinicians’ demographics as well as questions about the selected radiographs. The survey was distributed through Egyptian association of orthodontist’s partner to 200 members. RESULTS: comparison between orthodontists with three level of experience showed there was a statistically significant difference between the three groups regarding total score of correct tracing [P-value = 0.004, Effect size = 0.085]. Pair-wise comparisons revealed that Orthodontists with more than 10 years of experience showed the statistically significantly highest median score. There was no statistically significant difference between Orthodontists with experience less than 5 years and those with 5 – 10 years of experience; both showed statistically significantly lower median scores. CONCLUSIONS: Orthodontist with more than 10 year of experience showed higher prevalence of perception of dento- skeletal parameters on lateral cephalometric radiographs than the less experienced groups. No association was found between clinicians’ gender and perception of dento-skeletal parameters

Evaluation of accuracy and reliability of OneCeph digital cephalometric analysis in comparison with manual cephalometric analysis-a cross-sectional study

Introduction

Lateral cephalometric analysis continues to be one of the gold standard diagnostic aids in orthodontics, with various software available to enhance this.

Aim

This study was done to evaluate the accuracy and reliability of linear and angular measurements obtained from OneCeph digital cephalometric tracing and manual tracings in lateral cephalometry.

Methodology

This is a cross-sectional study done on twenty pre-treatment lateral cephalometric radiographs of subjects who reported to the postgraduate orthodontic clinic for orthodontic treatment over one month. Cephalometric tracings were done using OneCeph digital software and manual tracing method to evaluate nine parameters of Steiner’s cephalometric analysis. An Independent T-sample test was done between the mean values of manual and OneCeph tracing. Intra operator reliability was evaluated by paired T-test after a week.

Results

No significant statistical difference was observed as the p-value was greater than 0.05 for all the parameters in the two groups.

Conclusion

The reliability and accuracy of OneCeph software application was found to be at par with manual cephalometric tracing

The reliability and reproducibility of an Android cephalometric smartphone application in comparison with the conventional method

OBJECTIVES

To assess the reliability and reproducibility of linear and angular measurements of the cephalometric smartphone Android application OneCeph in comparison with the conventional method.

MATERIALS AND METHODS

A total number of 22 landmarks were registered, and 26 skeletal and dental cephalometric parameters were measured on 30 pretreatment cephalograms. The measurements for both digital (OneCeph) and conventional tracings were performed twice with a 4-week interval. The reliability (intraexaminer error) was evaluated by using the Pearson correlation coefficient. The variation in measurements between the tracing techniques (reproducibility) was determined by paired t-test.

RESULTS

The Pearson correlation coefficients of all cephalometric measurements for each tracing technique were ≥ 0.95. Significant differences between the two tracing techniques were detected in five measurements (SNB angle, N I to Pog linear measurement, U1-Apoint linear measurement, U lip to S line, and nasiolabial angle; P < .05).

CONCLUSIONS

Using 26 measurements to compare both tracing methods, all mean differences between the digital (OneCeph) and conventional methods were below 1 degree/1 mm, indicating that differences between the tracing methods were clinically insignificant. The U1-A point measurement was an exception for the digital method (OneCeph) with a clinically significant difference of 1.25 mm (P < .01); the difference was a result of wrongly measuring the distance from the A line to the incisor edge of the upper central incisor rather than the facial surface of the upper incisor. This leads to the conclusion that both tracing methods were reliable for daily clinical practice.

Craniofacial and Craniocervical Features in Cartilage-Hair Hypoplasia: A Radiological Study of 17 Patients and 34 Controls

BACKGROUND

Biallelic mutations in the non-coding RNA gene RMRP cause Cartilage-hair hypoplasia (CHH), a rare skeletal dysplasia in which the main phenotypic characteristic is severe progressive growth retardation.

OBJECTIVE

This study compared the cranial dimensions of individuals with CHH to healthy subjects.

METHODS

Lateral skull radiographs of 17 patients with CHH (age range 10 to 59 years) and 34 healthy individuals (age range 10 to 54 years) were analyzed for relative position of the jaws to skull base, craniofacial height and depth, as well as vertical growth pattern of the lower jaw, anterior cranial base angle, and the relationship between the cervical spine and skull base.

RESULTS

We found that the length of the upper and lower jaws, and clivus were significantly decreased in patients with CHH as compared to the controls. Anterior cranial base angle was large in patients with CHH. Basilar invagination was not found.

CONCLUSION

This study found no severe craniofacial involvement of patients with CHH, except for the short jaws. Unexpectedly, mandibular deficiency did not lead to skeletal class II malocclusion.

CLINICAL IMPACT

Although the jaws were shorter in patients with CHH, they were proportional to each other. A short posterior cranial base was not associated with craniocervical junction pathology.

Experiences with a new biplanar low-dose X-ray device for imaging the facial skeleton: A feasibility study

Background

This study aimed to evaluate the feasibility of a new biplanar low-dose X-ray device for facial skeletal imaging.

Methods

We evaluated 48 biplanar radiographs from 12 patients (posteroanterior/lateral), originally taken for a scoliosis examination with a biplanar low-dose X-ray device. For this study, the images were further evaluated for the perceptibility of 38 facial skeleton landmarks. To determine the reliability and reproducibility of perceptibility, two independent observers determined the landmarks twice, during a time interval of at least two weeks.

Results

Both interoperator and intraoperator reliability were excellent for all landmarks [intraclass correlation coefficient (ICC) > 0.92].

Conclusions

The biplanar low-dose X-ray device demonstrated good feasibility for precisely assessing the anatomical landmarks of the facial skeleton. Given its excellent precision, the biplanar low-dose X-ray device data sets should be forwarded from the treating orthopedic surgeon or neurosurgeon to the orthodontist or dentist for further assessment in their field.

Comparative Evaluation of Conventional and OnyxCeph™ Dental Software Measurements on Cephalometric Radiography

Objective

Cephalometry can be measured with traditionally conventional analysing methods (hand tracing), as well as using computers. Many dental softwares have been developed for this purpose. The reliability of these programs are often compared with the conventional method. The aim of the present study was to compare the conventional method of manual cephalometric analysis with a computerized one, OnyxCeph ™ (Image Instruments, Chemnitz, Germany) dental software.

Methods

Lateral cephalometric radiographs of 150 patients (75 males and 75 females) age range 12-34 were traced by two methods. Conventional method and computerized (OnyxCeph) cephalometric analysis method. 2 maxillar, 3 mandibular, 2 maxillo-mandibular, 3 vertical, 7 dental and 1 soft tissue parameters; 10 angular, 8 linear totally 18 cephalometric parameters were measured. Intra-class correlation coefficients were performed for both methods to assess the reliability of the measurements.

Results

The results 9 of 18 parameters were found statistically significant. They were Cd-A distance, Cd-Gn distance, Go-Me distance, GoGnSN angle, ANS-Me distance, upper incisor-NA distance, lower incisor-NB distance, lower incisor-NB angle, overbite distance.

Conclusion

Despite some discrepancies in measured values between hand-tracing cephalometric analysis method and the OnyxCeph cephalometric analysis method, statistical differences were minimal and only Cd-A, Cd-Gn, Go-Me, ANS-Me, GoGnSN° were clinically important for cephalometric analysis OnyxCeph was evaluated as an efficient method to replace conventional method.

Concurrent validity and reliability of cephalometric analysis using smartphone apps and computer software

OBJECTIVES

To assess the diagnostic accuracy of two smartphone cephalometric analysis apps compared with Viewbox software.

MATERIALS AND METHODS

Pretreatment digital lateral cephalograms of 50 consecutive orthodontic patients (20 males, 30 females; mean age, 19.1 years; SD, 11.7) were traced twice using two apps (ie, CephNinja and OneCeph), with Viewbox used as the gold standard computer software program. Seven angular and two linear measurements, originally derived from Steiner cephalometric analysis, were performed.

RESULTS

Regarding validity, intraclass correlation coefficients (ICCs) ranged from .903-.983 and .786-.978 for OneCeph vs Viewbox and CephNinja vs Viewbox, respectively. The ICC values for intratool reliability ranged from .647-.993. None of the CephNinja measurements was below the recommended cutoff values of ICCs for reliability.

CONCLUSIONS

OneCeph has a high validity compared with Viewbox, while CephNinja is the best alternative to Viewbox regarding reliability. Smartphone apps may have a great potential in supplementing traditional cephalometric analysis.

Evaluation of an online website-based platform for cephalometric analysis

BACKGROUND

The purpose of our study was to assess the reproducibility of linear and angular measurements of cephalogram tracings made with an online website-based platform CephX® vs. tracings made using the FACAD® computer software.

METHODS

Thirty cephalometric radiographs were selected randomly to be used in this study. A total of 16 landmarks and 16 measurements (8 linear and 8 angular) were defined. We used paired t-test to compare mean differences between both methods. Concordance Correlation Coefficient (CCC) and Bland-Altman analyses were used to evaluate reproducibility of measurements. The level of statistical significance was set at P < 0.05.

RESULTS

We did not find a statistically significant mean difference between the two methods except for two angular measurements SNA, FMA and one linear measurement Pg to NB. The highest magnitude of the difference between sample means was 1.9° and 0.78 mm for the angular and linear measurements respectively. The SE value was less than 0.1° for the angular measurements and less than 0.3 mm for the linear measurements. All parameters except POG to NB showed moderate to almost perfect agreement (>0.90).

CONCLUSION

The measurements obtained by both softwares FACAD® and CephX® are reproducible. Although significant differences were detected for some measurements, all differences were not clinically significant.

The Difference in Cervical Vertebral Skeletal Maturation between Cleft Lip/Palate and Non-Cleft Lip/Palate Orthodontic Patients

Objective

The aim was to evaluate differences in the cervical vertebral skeletal maturity of unilateral cleft lip and palate (UCLP) and non-cleft lip/palate (non-CLP) Saudi male orthodontic patients.

Method

This cross-sectional multicenter study took place at the dental school, King Saud University and King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, between October 2014 and September 2015. The records of Saudi male orthodontic patients with UCLP (n = 69) were collected. Cervical vertebral maturation was assessed using their cephalometric radiographs. The records of 138 age-matched non-CLP Saudi male orthodontic patients served as controls.

Results

There was a significant difference in skeletal maturity between the UCLP and non-CLP groups, as evident in the delayed skeletal development among the UCLP participants. Moreover, pubertal growth spurt onset was significantly earlier in the non-cleft participants in comparison with the UCLP participants (p = 0.009).

Conclusions

There is delayed skeletal maturity among the UCLP Saudi male population in comparison with their non-CLP age-matched peers.

Assessing the Reliability of Digitalized Cephalometric Analysis in Comparison with Manual Cephalometric Analysis

INTRODUCTION

For more than seven decades orthodontist used cephalometric analysis as one of the main diagnostic tools which can be performed manually or by software. The use of computers in treatment planning is expected to avoid errors and make it less time consuming with effective evaluation and high reproducibility.

AIM

This study was done to evaluate and compare the accuracy and reliability of cephalometric measurements between computerized method of direct digital radiographs and conventional tracing.

MATERIALS AND METHODS

Digital and conventional hand tracing cephalometric analysis of 50 patients were done. Thirty anatomical landmarks were defined on each radiograph by a single investi-gator, 5 skeletal analysis (Steiner, Wits, Tweeds, McNamara, Rakosi Jarabaks) and 28 variables were calculated.

RESULTS

The variables showed consistency between the two methods except for 1-NA, Y-axis and interincisal angle measurements which were higher in manual tracing and higher facial axis angle in digital tracing.

CONCLUSION

Most of the commonly used measurements were accurate except some measurements between the digital tracing with FACAD^® and manual methods. The advantages of digital imaging such as enhancement, transmission, archiving and low radiation dosages makes it to be preferred over conventional method in daily use.

The use of three-dimensional cephalometric references in dentoskeletal symmetry diagnosis

OBJECTIVE:

The aim of this study is to assess dentoskeletal symmetry in cone-beam computed tomography (CBCT) scans of Brazilian individuals with Angle Class I malocclusion.

MATERIAL:

A total of 47 patients (22 females and 25 males) aged between 11 and 16 years old (14 years) seen in a private radiology service (CIRO, Goiânia, GO, Brazil) were assessed. All CBCT scans were obtained from January, 2009 to December, 2010. Cephalometric measurements were taken by multiplanar reconstruction (axial, coronal and sagittal) using Vista Dent3DPro 2.0 (Dentsply GAC, New York, USA). Minimum, maximum, mean and standard deviation values were arranged in tables, and Student t-test was used to determine statistical significance (P < 0.05).

RESULTS:

Data were homogeneous, and differences between the right and left sides were not significant.

CONCLUSIONS:

Cephalometric measurements of Brazilian individuals with Angle Class I malocclusion can be used to establish facial symmetry and three-dimensional standard references which might be useful for orthodontic and surgical planning.

Comparative evaluation of cephalometric measurements of monitor-displayed images by Nemoceph software and its hard copy by manual tracing

OBJECTIVE

The aim of this study was to evaluate and compare the cephalometric measurements obtained from computerized tracing of direct digital radiographs and hand tracing of their digital radiographic printouts.

MATERIAL AND METHODS

The soft- and hard-copies of pre-treatment lateral cephalograms of 40 subjects (both males and females) within the age group of 10-30 years, irrespective of the type of malocclusion were taken. Total 26 measurements (13 linear and 13 angular) were obtained using both the manual and the digital technique.

RESULTS

Amongst the linear measurements, Anterior facial height (AFH), Posterior facial height (PFH), Upper lip length (ULL), Lower lip length (LLL), Anterior cranial base length (ACBL), Posterior cranial base length (PCBL), Maxillary length (MxL), Mandibular length (MdL), Lower incisor to NB line (L1 to NB) and Lower lip protrusion (LLP) showed statistically significant difference between the two techniques but were clinically acceptable (difference between the digital and manual technique were less than 2 units (1 unit = 1 mm for linear measurements and 1° for angular measurements). While amongst the angular measurements, only occlusal plane angle showed statistically significant difference between the two techniques that was not clinically acceptable.

CONCLUSION

Digital measurements obtained from monitor-displayed images (soft copy) were found to be reproducible and comparable to the manual method done on its hard copy, for all the measurements except occlusal plane angle (SN-occlusal plane).

Comparison of manual, digital and lateral CBCT cephalometric analyses

OBJECTIVE

The aim of this study was to compare the reliability of three different methods of cephalometric analysis.

MATERIAL AND METHODS

Conventional pretreatment lateral cephalograms and cone beam computed tomography (CBCT) scans from 50 subjects from a radiological clinic were selected in order to test the three methods: manual tracings (MT), digitized lateral cephalograms (DLC), and lateral cephalograms from CBCT (LC-CBCT). The lateral cephalograms were manually analyzed through the Dolphin Imaging 11.0™ software. Twenty measurements were performed under the same conditions, and retraced after a 30-day period. Paired t tests and the Dahlberg formula were used to evaluate the intra-examiner errors. The Pearson's correlation coefficient and one-way analysis of variance (ANOVA) tests were used to compare the differences between the methods.

RESULTS

Intra-examiner reliability occurred for all methods for most of the measurements. Only six measurements were different between the methods and an agreement was observed in the analyses among the 3 methods.

CONCLUSIONS

The results demonstrated that all evaluated methodologies are reliable and valid for scientific research, however, the method used in the lateral cephalograms from the CBCT proved the most reliable.

Reproducibility of measurements in tablet-assisted, PC-aided, and manual cephalometric analysis

OBJECTIVE

To assess the reproducibility of cephalometric measurements performed with software for a tablet, with a program for personal computers (PCs), and manually.

MATERIALS AND METHODS

The pretreatment lateral cephalograms of 20 patients that were acquired using the same digital cephalometer were collected. Tracings were performed with NemoCeph for Windows (Nemotec), with SmileCeph for iPad (Glace Software), and by hand. Landmark identification was carried out with a mouse-driven cursor using NemoCeph and with a stylus pen on the iPad screen using SmileCeph. Hand tracings were performed on printouts of the cephalograms, using a 0.3-mm 2H pencil and a protractor. Cephalometric landmarks and linear and angular measurements were recorded. All the tracings were done by the same investigator. To evaluate reproducibility, for each cephalometric measurement the agreement between the value derived from NemoCeph, that given by SmileCeph and that measured manually was assessed with the intraclass correlation coefficient (ICC). Agreement was rated as low for an ICC≤0.75, and an ICC>0.75 was considered indicative of good agreement. Also, differences in measurements between each software and manual tracing were statistically evaluated (P<.05).

RESULTS

All the measurements had ICC>0.8, indicative of a high agreement among the tracing methods. Relatively lower ICCs occurred for linear measurements related to the occlusal plane and to N perpendicular to the Frankfurt plane. Differences in measurements between both software programs and hand tracing were not statistically significant for any of the cephalometric parameters.

CONCLUSION

Tablet-assisted, PC-aided, and manual cephalometric tracings showed good agreement.

The reliability and reproducibility of cephalometric measurements: a comparison of conventional and digital methods

OBJECTIVE

The aim of this study was to assess the reliability and reproducibility of angular and linear measurements of conventional and digital cephalometric methods.

METHODS

A total of 13 landmarks and 16 skeletal and dental parameters were defined and measured on pre-treatment cephalometric radiographs of 30 patients. The conventional and digital tracings and measurements were performed twice by the same examiner with a 6 week interval between measurements. The reliability within the method was determined using Pearson's correlation coefficient (r²). The reproducibility between methods was calculated by paired t-test. The level of statistical significance was set at p < 0.05.

RESULTS

All measurements for each method were above 0.90 r² (strong correlation) except maxillary length, which had a correlation of 0.82 for conventional tracing. Significant differences between the two methods were observed in most angular and linear measurements except for ANB angle (p = 0.5), angle of convexity (p = 0.09), anterior cranial base (p = 0.3) and the lower anterior facial height (p = 0.6).

CONCLUSION

In general, both methods of conventional and digital cephalometric analysis are highly reliable. Although the reproducibility of the two methods showed some statistically significant differences, most differences were not clinically significant.

Comparison of linear and angular measurements using two-dimensional conventional methods and three-dimensional cone beam CT images reconstructed from a volumetric rendering program in vivo

OBJECTIVE

The aim of this study was to compare the linear and angular measurements made on two-dimensional (2D) conventional cephalometric images and three-dimensional (3D) cone beam CT (CBCT) generated cephalograms derived from a 3D volumetric rendering program.

METHODS

Pre-treatment cephalometric digital radiographs of 11 patients and their corresponding CBCT images were randomly selected. The digital cephalometric radiographs were traced using Vista Dent OC (GAC International, Inc Bohemia, NY) and by hand. CBCT and Maxilim® (Medicim, Sint-Niklass, Belgium) software were used to generate cephalograms from the CBCT data set that were then linked to the 3D hard-tissue surface representations. In total, 16 cephalometric landmarks were identified and 18 widely used measurements (11 linear and 7 angular) were performed by 2 independent observers. Intraobserver reliability was assessed by calculating intraclass correlation coefficients (ICC), interobserver reliability was assessed with Student t-test and analysis of variance (ANOVA). Mann-Whitney U-tests and Kruskal-Wallis H tests were also used to compare the three methods (P < 0.05).

RESULTS

The results demonstrated no statistically significant difference between interobserver analyses for CBCT-generated cephalograms (P < 0.05), except for Gonion-Menton (Go-Me) and Condylion-Gnathion (Co-Gn). Intraobserver examinations showed low ICCs, which was an indication of poor reproducibility for Go-Me and Sella-Nasion (S-N) in CBCT-generated cephalograms and poor reproducibility for Articulare-Gonion (Ar-Go) in the 2D hand tracing method (P < 0.05). No statistical significance was found for Vista Dent OC measurements (P > 0.05).

CONCLUSIONS

Measurements from in vivo CBCT-generated cephalograms from Maxilim® software were found to be similar to conventional images. Thus, owing to higher radiation exposure, CBCT examinations should only be used when the inherent 3D information could improve the outcome of treatment.

Accuracy and repeatability of computer aided cervical vertebra landmarking in cephalogram

The accuracy and repeatability of computer aided cervical vertebra landmarking (CACVL) were investigated in cephalogram. 120 adolescents (60 boys, 60 girls) aged from 9.1 to 17.2 years old were randomly selected. Twenty-seven landmarks from the second to fifth cervical vertebrae on the lateral cephalogram were identified. In this study, the system of CACVL was developed and used to identify and calculate the landmarks by fast marching method and parabolic curve fitting. The accuracy and repeatability in CACVL group were compared with those in two manual landmarking groups [orthodontic experts (OE) group and orthodontic novices (ON) group]. The results showed that, as for the accuracy, there was no significant difference between CACVL group and OE group no matter in x-axis or y-axis (P>0.05), but there was significant difference between CACVL group and ON group, as well as OE group and ON group in both axes (P<0.05). As for the repeatability, CACVL group was more reliable than OE group and ON group in both axes. It is concluded that CACVL has the same or higher accuracy, better repeatability and less workload than manual landmarking methods. It's reliable for cervical parameters identification on the lateral cephalogram and cervical vertebral maturation prediction in orthodontic practice and research.

Long term stability of mandibular advancement procedures: bilateral sagittal split osteotomy versus distraction osteogenesis

The aim of this study was to compare the postoperative stability of the mandible after a bilateral lengthening procedure, either by bilateral sagittal split osteotomy (BSSO) or distraction osteogenesis (DO). All patients who underwent mandibular advancement surgery between March 2001 and June 2004 were evaluated. There were 17 patients in the BSSO group and 18 patients in the DO group. The decision to use intra-oral distraction or BSSO for mandibular advancement primarily depended on the choice of the patient and their parents. In both groups, standardized cephalometric radiographs were taken preoperatively, postoperatively (BSSO group) or directly post-distraction (DO group) and during the last study measurement in May 2008. Cephalometric analysis was performed using the following measurements: sella/nasion-mandibular point B and sella/nasion-mandibular plane. Point B was used to estimate relapse. This study showed no significant difference in relapse between the BSSO and the DO groups measured 46-95 months after advancement of the mandible (P>.05). It can be concluded from this study that there is no postoperative difference in the stability between BSSO and DO after mandibular advancement after 4 years.

The 3D CT superimposition method using image fusion based on the maximum mutual information algorithm for the assessment of oral and maxillofacial surgery treatment results

OBJECTIVE

The usefulness of image fusion based on the maximum mutual information algorithm was investigated for the assessment of oral and maxillofacial surgery treatment results.

STUDY DESIGN

Superimposition was performed using image fusion of 25 CBCT images of a human skull under the assumption of different spatial conditions and 41 patients' image data. Errors were measured using distances between titanium markers on the skull. The degree of shared image information was defined as normalized mutual information (NMI) value to assess robustness of image fusion.

RESULTS

The mean error was 0.396 mm (± 0.142 mm) and was not affected by positional change (P > .05). Mandibular shifts showed significantly different (P = .000) NMI values but shared information was not significantly affected by the degree of surgical changes in patients' CT (P = .176).

CONCLUSIONS

For the evaluation of surgical treatment results, image fusion is an accurate and reliable method that is not affected by spatial or surgical changes.

Reliability of four different computerized cephalometric analysis programs

The aim of this investigation was to compare the traditional method of manual cephalometric tracing with four different computerized tracing programs, where the lateral cephalograms were scanned at 300 dpi and digitized onscreen. Thirty randomly selected cephalometric radiographs were used in this study. Four programs Dolphin Imaging, Vistadent, Nemoceph, and Quick Ceph were evaluated. Three dental, 11 skeletal, and 1 soft tissue parameters were measured that consisted of 5 linear and 10 angular measurements. Statistical analysis was carried out using multivariate analysis of variance and Box's and Levene's tests. No statistically significant difference was found between manual tracing and the computerized tracing programs. The measurements obtained with the cephalometric analysis programs used in the study were reliable.

Reliability and the smallest detectable differences of lateral cephalometric measurements

INTRODUCTION

The aim of this study was to determine the reliability and the measuring error (by means of the smallest detectable error) of 11 angular and 4 linear measurements commonly used for cephalometric analysis.

METHODS

Twenty-five digital lateral cephalograms were randomly selected and traced with Viewbox software (version 3.1.1.13, dHAL Software, Kifissia, Greece). This was repeated 3 times by 2 observers during 3 sessions. There was at least 1 week between each session. Differences were analyzed with a repeated measurement analysis of variance (ANOVA). Intraobserver and interobserver reliabilities were calculated with intraclass correlation coefficients (ICC) based on absolute agreement. Measurement error was determined by means of the smallest detectable difference.

RESULTS

The intraobserver agreement of the measurements was good (ICC >0.82). SNA, SNB, ANB, and ANS-Me had the smallest intraobserver errors for both observers (>1.86 mm or degrees). Except for SN-FH (ICC = 0.76), interobserver agreement was good (ICC >0.87).

CONCLUSIONS

Determining the appropriate measuring error of cephalometric measurements by means of the smallest detectable difference is necessary to find the true difference between the start and the end of active treatment. Depending on the magnitude of clinical significance, the measuring error was possibly clinically significant for all variables tested and, therefore, questions the use of these variables to detect the true treatment effect.

A comparison of hand-tracing and cephalometric analysis computer programs with and without advanced features--accuracy and time demands

The aim of this study was to evaluate the basic and advanced features of five different cephalometric analysis computer programs. The level of measurement agreement with hand-tracing and time demands was examined. The material consisted of 30 digital lateral radiographic images. Twenty-three measurements were calculated by one operator both manually and using five different cephalometric analysis software programs. Intraclass correlation coefficient (ICC) was used to detect differences in measurement agreement between hand-tracing and basic features as well as between hand-tracing and advanced features. Coefficient of variation (CV) was used to assess intra-user error and a Student's t-test to determine time differences. Of the 23 measurements tested for each procedure, one [(Ii to NB (mm)] showed better agreement with hand-tracing when the advanced features were used, 20 showed good agreement with hand-tracing for both basic and advanced features, while two (AB on FOP and Ii to A/Pog) showed poor intra-user reproducibility. Hand-tracing took a significantly longer time (P < 0.001) than both the basic and advanced features. The advanced features took a significantly longer time (P < 0.001) than the basic features. Both basic and advanced features showed good measurement agreement with the hand-tracing technique. The use of the basic features minimizes the time requirements for analysis. A computerized tracing technique, which consists of either basic or advanced feature, can be regarded as less time consuming and equally reliable to hand-tracing as far as cephalometric measurements are concerned.

Novel information theory based method for superimposition of lateral head radiographs and cone beam computed tomography images

OBJECTIVES

The aim was to introduce a novel alignment criterion, focus mutual information (FMI), for the superimposition of lateral cephalometric radiographs and three dimensional (3D) cone beam computed images as well as the assessment of the alignment characteristics of the new method and comparison of the novel methodology with the region of interest (ROI) approach.

METHODS

Implementation of a FMI criterion-based methodology that only requires the approximate indication of stable structures in one single image. The robustness of the method was first addressed in a phantom experiment comparing the new technique with a ROI approach. Two consecutive cephalometric radiographs were then obtained, one before and one after functional twin block application. These images were then superimposed using alignment by FMI where the following were focused on, in several ways: (1) cranial base and acoustic meatus, (2) palatal plane and (3) mandibular symphysis. The superimposed images were subtracted and coloured. The applicability to cone beam CT (CBCT) is illustrated by the alignment of CBCT images acquired before and after craniofacial surgery.

RESULTS

The phantom experiment clearly shows superior alignment when compared to the ROI approach (Wilcoxon n = 17, Z = -3.290, and P = 0.001), and robustness with respect to the choice of parameters (one-sample t-test n = 50, t = -12.355, and P = 0.000). The treatment effects are revealed clearly in the subtraction image of well-aligned cephalometric radiographs. The colouring scheme of the subtraction image emphasises the areas of change and visualizes the remodelling of the soft tissue.

CONCLUSIONS

FMI allows for cephalometry without tracing, it avoids the error inherent to the use of landmarks and the interaction of the practitioner is kept to a minimum. The robustness to focal distribution variations limits the influence of possible examiner inaccuracy.

Comparison of hand-traced and computer-based cephalometric superimpositions

OBJECTIVE

To determine the ability to produce comparable superimpositions using hand tracing and digital methods (Dolphin v10). In addition, if the two methods were comparable, we wanted to determine if a difference existed between the best-fit cranial base superimposition and S-N superimpositions using the digital method.

METHODS AND MATERIALS

Sixty-four initial (T(1)) and final (T(2)) cephalometric film radiographs were obtained. Cranial base and regional superimpositions were completed independently for each pair of radiographs by either hand tracing and digital methods. To quantitatively evaluate the differences between the two methods, the hand and digital superimpositions were digitized to obtain x-y coordinates of routine cephalometric landmarks at T(2). Linear distance between multiple corresponding (hand and digital) T(2) cephalometric landmark locations (e.g., A point) were measured and defined as the T(2) landmark distance (T(2) LD). Additionally, 61 patient records were used to compare the digital method for best-fit cranial base superimpositions versus S-N superimpositions. A Friedman test was applied to examine for differences.

RESULTS

The upper 95% confidence limit for the mean of the T(2) LD for hand and digital superimposition methods was <1 mm for all landmarks except maxillary incisor tip and apex. The upper 95% confidence interval for best-fit vs S-N was >1 mm for most landmarks.

CONCLUSION

This study validates the use of superimpositions produced by Dolphin Imaging version 10 and is a necessary step forward toward widespread acceptance of digital superimpositions.

An evaluation of cellular neural networks for the automatic identification of cephalometric landmarks on digital images

Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE) were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59 mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged.

Evaluation of speed, repeatability, and reproducibility of digital radiography with manual versus computer-assisted cephalometric analyses

The aims of this study were to evaluate intra-examiner repeatability and inter-examiner reproducibility of landmarks using two cephalometric analysing techniques, manual and computerized, and to compare these for speed. One hundred lateral cephalometric radiographs were randomly selected and 11 angular and six linear parameters were traced and measured by two examiners using the manual method and Dolphin Image Software 9.0 on each radiograph. A Student's t-test for paired and independent samples was used to compare the mean values of intra- and inter-examiner differences. Intraclass correlation coefficients (ICC) were calculated to determine intra- and inter-examiner correlation (r value). Both operators were generally consistent in the repeated measurements; however, for one examiner, the differences for Na is perpendicular to A (P < 0.001), Na is perpendicular Pog, and U1-NA (P < 0.01) distance measurements were found to be statistically significant. Intra-examiner repeatability of landmarks both with the manual and Dolphin techniques showed high correlation coefficients. While inter-examiner reproducibility of landmarks was unacceptable, measurement errors with the manual technique were generally comparable with the Dolphin technique. The mean tracing times of the two operators for a single tracing was 2 minutes 41 seconds for Dolphin and 6 minutes 51 seconds for manual tracings. Computer-assisted cephalometric analysis does not increase intra- and inter-examiner reliability but can result in time saving.

Differences in cephalometric measurements: a comparison of digital versus hand-tracing methods

The aim of this study was to evaluate the accuracy of cephalometric measurements using computerized tracing of direct digital radiographs in comparison with hand tracing of digital radiographic printouts. Comparisons were made between methods in terms of accuracy of individual measurements as well as evaluation of treatment outcomes. Pre- (T1) and post- (T2) treatment cephalometric digital radiographs of 30 patients were traced using the Vistadent OC 1.1 computer software program (group 1) and manually (group 2) by the same investigator. A total of 26 anatomical landmarks were located and measured. Measurement reproducibility was evaluated by calculating intraclass correlation coefficients, and paired t-tests were used to compare differences in individual measurements and treatment outcomes between methods. Differences greater than 0.05 were considered to be statistically significant. Significant differences were found between the two methods for SNB, Wits appraisal, Cd-A, Cd-Gn, FMA, SN-PP, U1-NA (mm), U1-FH, L1-NB (mm), and Li-E plane. No significant differences were found between the two methods in the measurement of treatment changes. Cephalometric measurements of most parameters were reproducible for both methods. Despite some discrepancies in measured values between hand-tracing and the computerized method, any differences were minimal and clinically acceptable.

A comparison of manual traced images and corresponding scanned radiographs digitally traced

The aim of this study was to compare the accuracy of cephalometric measurements made with digital tracing software (FACAD) with equivalent hand-traced measurements, and to evaluate the reproducibility of each method. Pre- and post-surgical lateral cephalographs of 30 adult patients (12 males and 18 females, median age = 25 years, standard deviation = 8.7) who had undergone orthognathic treatment were scanned into a computer. One operator identified 25 landmarks digitally on the computer display and manually on acetate paper. Measurements on the 60 radiographs were duplicated, and measurement error of each method was determined with interclass correlation. A paired t-test was used to detect differences between the manual and digital methods. Overall, greater variability in digital cephalometric measurements was found. Differences in Gn', Li, Si, and Ii-Li measurements between the two methods were statistically (P < 0.05), but not clinically significant. The findings indicate that the results of the two investigated tracing methods are similar and that digital tracing with FACAD is reliable and can be used routinely.

Comparison of cephalometric measurements with digital versus conventional cephalometric analysis

The aim of this study was to evaluate the accuracy and reliability of angular and linear cephalometric measurements using a computerized method of direct digital radiographs. This was then compared with the measurements obtained with a computerized method that uses a digitizing pad and hand tracing of printout radiographs. Pre-treatment digital cephalometric radiographs of 125 patients were traced using Vistadent 2.1 AT and Jiffy Orthodontic Evaluation (JOE) software programs and by hand tracing of the printouts. Twenty-six anatomical landmarks were defined on each radiograph by a single investigator and 28 variables were calculated. Statistical analysis was undertaken using one-way analysis of variance and multiple group comparisons using Duncan's test at a significance level of 0.05. Low correlation coefficients indicated poor reproducibility for nasolabial angle for each of the three methods (P > 0.05). Most of the variables showed consistency between the three methods except for nasolabial angle, ANS-Me, APFH, L1-NB, Nperp-Pg, Go-Me, and U1-NA measurements. The findings indicated that most of the cephalometric measurements were highly reproducible with direct digital radiographs using Vistadent 2.1 AT as well as with printouts using both JOE software and hand tracing. Despite the low correlation for some measurements between the Vistadent 2.1 AT, JOE, and hand-tracing methods, most of the commonly used measurements were accurate. The user-friendly and time-saving nature of the computerized method using digital radiographs makes it the preferred option.

Reliability of cranial base measurements on lateral skull radiographs

OBJECTIVE

To explore the reliability of identification of anatomic landmarks on lateral skull radiographs of young unaffected individuals that has conventionally been used to diagnose pathologic relationships in the craniovertebral junction.

MATERIAL AND METHODS

From the Helsinki longitudinal growth study, 20 randomly selected lateral radiographs were analyzed and re-analyzed by two examiners. Both located seven cephalometric landmarks based on which five measurements were calculated. The differences of results were compared. With similar method three radiographs were analysed by 11 examiners and results were compared.

RESULTS

Some anatomic landmarks were easier to locate than others on lateral skull radiographs leading to differences in measurements based on them. We found the magnitude of the difference to be dependent on the landmark serving as reference. Inter- and intra-examiner errors were of similar magnitude, although intra-examiner error declined in the repeated landmark identification. Variation in a single landmark location had in general little effect on the measurement value.

CONCLUSION

Variations in landmark location lead to differences in numeric evaluation of the anatomic relationships in the skull base area. These differences were, however, shown to have little clinical significance. Hence, the documented methods are applicable for screening of basilar pathology.