[Cephalometry and information technics. I. Automated cephalometry].
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Automation↗
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Surgical correction of nasal obstruction in the treatment of mild sleep apnoea: importance of cephalometry in predicting outcome.
BACKGROUND: A study was undertaken to determine if cephalometric radiographs could identify those who will benefit from nasal surgery in patients with a sleep apnoea hypopnoea syndrome (SAHS) and chronic nasal obstruction. METHODS: Fourteen patients with SAHS were enrolled. Those with normal posterior airway space and mandibular plane to hyoid bone distances on preoperative cephalometric radiographs were matched with those with abnormal cephalometry for the frequency of sleep disordered breathing and body mass index. Polysomnographic studies (all subjects) and nasal resistance measurements (n = 10) were performed one to three months before and two to three months after surgery (septoplasty, turbinectomy, and polypectomy). RESULTS: There was no difference in the baseline results of the polysomnographic studies between the two groups of patients. Nasal resistance decreased from a mean (SE) value of 2.9 (0.3) cm H2O/l/s before surgery to 1.4 (0.1) cm H2O/l/s after surgery in the normal cephalometry group and from 2.7 (0.3) cm H2O/l/s to 1.3 (0.3) cm H2O/l/s in the other group. The apnoea + hypopnoea index returned to normal (< 10 breathing abnormalities/hour) in all but one subject with normal cephalometric measurements, and sleep fragmentation improved with a decrease in the arousal index from 23.9 (3.3)/hour at baseline to 10.6 (2.5)/hour after surgery. Both of these parameters remained unchanged after surgery in the patients with abnormal cephalometry. CONCLUSIONS: Normal cephalometry is helpful in identifying patients with mild SAHS and nasal obstruction who will benefit from nasal surgery. The presence of craniomandibular abnormalities makes it unlikely that nasal surgery will improve sleep related breathing abnormalities.
Adult↗
A rigorous comparison of real time and B scan cephalometry.
Real time cephalometry has been compared with B scan cephalometry by a rigorous method with complete partition of variables. Analysis was by standard analysis of variance techniques. Systematic and random errors between and within observers, machines and days have been evaluated. The largest systematic error has been shown to be between machines. This is due to failure to align the beam precisely at right angles to the mid-line of the fetal head using B scanners. Real time scanners with bar calipers are, therefore, superior to B scanners for cephalometry. There is a lesser difference between observers. An additional element of variability arises when measurements are made on different days but this is smaller than other sources of variation and smaller than the random variation. Random errors are described by a standard deviation of 1 mm and systematic errors are all numerically smaller than this.
Analysis of Variance↗
Comparison between urinary oestrogen assay and serial ultrasonic cephalometry in assessment of fetal growth retardation.
Urinary oestrogen assay and serial ultrasonic cephalometry were performed on 284 patients who were considered on clinical grounds to be at risk of having a growth-retarded fetus. It was found that ultrasonic cephalometry was significantly better than oestrogens in diagnosing the small-for-dates baby, but that there was no significant difference between the two methods in predicting perinatal asphyxia. Of the 14 stillbirths, three were in the normal ultrasonic growth rate group and five had normal oestrogen excretion. Both methods were found to be of value in the diagnosis of fetal growth-retardation, although cephalometry would seem to have some advantages, especially in distinguishing between fetal growth-retardation and mistaken maturity.
Adult↗
Predictive value of Müller maneuver, cephalometry and clinical features for the outcome of uvulopalatopharyngoplasty. Evaluation of predictive factors using discriminant analysis in 30 sleep apnea patients.
The success rate of uvulopalatopharyngoplasty (UPPP) in the treatment of obstructive sleep apnea is generally only 50-60%. In order to improve this, various predictive factors for the outcome of UPPP were studied, including the Müller maneuver and cephalometry. Thirty unselected consecutive patients with obstructive sleep apnea (median apnea index (AI) 26 apneas/h, range 5-78) underwent UPPP with standard tonsillectomy except in the case of small tonsils and using CO2 laser for the palatal resection. Polysomnographic control 5 months after surgery showed that 63% of all patients had obtained a reduction in AI > or = 50% including an AI < 20 after surgery. Tonsillectomy had no influence on the outcome. Further, the Müller maneuver did not predict the outcome, whereas cephalometry proved to be of good predictive value. Lowered position of the hyoid bone, increased cranio-cervical angle and shortening of the maxilla length were significantly associated with poor results of UPPP, as were overweight, narrowing of the hypopharynx, the severity of sleep apnea, and hypersomnia. However, in a discriminant analysis containing all these variables, the three cephalometric measurements together with hypersomnia were most closely associated with the outcome of UPPP. A predictive model containing these four variables could correctly classify 83% of the patients in the present study. The model had a false positive rate of 7% in predicting a successful outcome. This indicates that cephalometry is mandatory in the selection of UPPP candidates and that a predictive model containing some or all of the four variables may substantially improve the success rate.
Adult↗
[Development of a video system for three-dimensional cephalometry and dental cast analysis].
OBJECTIVE: The purpose of this article is to introduce the outline of our newly developed video system for three-dimensional cephalometry and dental cast analysis. METHODS: The video measuring technique was utilized in the field of dentistry in our study. Two CCD cameras were used to capture the images both of the dental cast and headfilms. The dental cast analysis and three-dimensional cephalometry shared a set of operating system. The three-dimensional reconstruction was based on the LAT and PA films. RESULTS: The measurement error of dental cast analysis is less than 0.09 mm, and the error of three-dimensional cephalometry is less than 0.45 mm. CONCLUSIONS: The clinical application suggests that the use of our system is feasible not only for clinical evaluation of malocclusion but also for saving time necessary for treatment planing and diagnosis.
Cephalometry↗
[Antenatal assessment of fetal maturity--a comparison of ultrasound-cephalometry and radiology (author's transl)].
334 ultrasound-cephalometries and 231 X-ray fetographies were performed for antenatal assessment of fetal maturity as well as for exact estimation of gestational age in women with unknown date of donfinement. The accurance of the predictions was compared. Ultrasound-cephalometry gave best results when performed until the 20th week of gestation. A correct prediction was obtained in 80.4% of cases. After the 20th week of gestation, the accuracy of prediction decreased. Radiology on the contrary gave optimal results at the end of pregnancy. A correct prediction of the date of confinement was obtained in 73.8% of cases, when the X-ray fetography was performed between the 37th and 40th week of gestation. At the end of gestation radiography should be performed, if there is a discrepancy between ultrasound and clinical estimation or if ultrasound-cephalometry was not carried out in early pregnancy--especially if induction of labour is necessary.
Cephalometry↗
Accuracy of cephalometry in measurements of postoperative migration of the maxilla after Le Fort I osteotomy.
The aim of the study was to evaluate the accuracy of cephalometry when point A is used to assess the migration of the maxilla following Le Fort I osteotomy. In 10 consecutive patients, postoperative migration of the maxilla was studied by means of cephalometry and x-ray stereometry. Because the precision and accuracy of the x-ray stereometric method are known to be high, this method was used as a norm against which the results obtained by cephalometry were compared. The values of postoperative migration obtained by cephalometric analysis exceeded the corresponding values obtained by x-ray stereometry in all but four recordings. In 16 of 40 recordings, migration in opposite directions was found. The differences were statistically significant. Cephalometric analysis may be an inaccurate tool for postoperative follow-up of minor segment migration such as that usually found after osteotomies.
Cephalometry↗
A simulator for maxillofacial surgery integrating 3D cephalometry and orthodontia.
OBJECTIVES: This paper presents a new simulator for maxillofacial surgery that gathers the dental and maxillofacial analyses together into a single computer-assisted procedure. The idea is to first propose a repositioning of the maxilla via the introduction of 3D cephalometry applied to a 3D virtual model of the patient's skull. Orthodontic data are then integrated into this model, using optical measurements of plaster casts of the teeth. MATERIALS AND METHODS: The feasibility of the maxillofacial demonstrator was first evaluated on a dry skull. To simulate malformations (and thus simulate a "real" patient), the skull was modified and manually cut by the surgeon to generate a given maxillofacial malformation (with asymmetries in the sagittal, frontal, and axial planes). RESULTS: The validation of our simulator consisted of evaluating its ability to propose a bone repositioning diagnosis that would restore the skull to its original configuration. An initial qualitative validation is provided in this paper, with a 1.5-mm error in the repositioning diagnosis. CONCLUSIONS: These results mainly validate the concept of a maxillofacial numerical simulator that integrates 3D cephalometry and guarantees a correct dental occlusion.
Cephalometry↗
Integration of three-dimensional cephalometry and 3D-skull models in combined orthodontic/surgical treatment planning.
In 15 adult patients with severe dentomaxillofacial deformities we integrated 3-dimensional cephalometry and 3D-model surgery with individually milled or stereolithographically built skull models in our combined orthodontic/surgical diagnosis and treatment planning. After the generation of contiguous axial CT-scans the CT data sets were transferred to a commonly used computing system (IBM-PC) to reconstruct 3D-images from any point of view. After the definition of measurement points, distances and angles at the skin and bone surface a 3-dimensional cephalometric analysis could be performed directly in the 3D-objects on the monitor. This allows a quantitative assessment of skeletal asymmetries. The transfer of CT data to life-size 3D-skull models and replacement of imprecise dental arches by dental casts different orthodontic and surgical treatment concepts could be evaluated. The 3D-model surgery represents a new quality of treatment prediction in the individual dentomaxillofacial morphology. The orthodontic set-up and 3D-model surgery permit a verification of the feasibility of the most suitable mobilization and placement of bone segments. The clinical treatment sequences indicated that the integration of 3-dimensional cephalometry and 3D-model surgery in patients with severe asymmetric dentomaxillofacial deformities allowed a higher precision of diagnosis and treatment planning.
Adult↗
Phosphor-stimulated computed cephalometry: reliability of landmark identification.
The aim of this randomized, controlled, prospective study was to determine the reliability of computed lateral cephalometry (Fuji Medical Systems, Tokyo, Japan) in terms of landmark identification compared to conventional lateral cephalometry (CAWO, Schrobenhausen, Germany). To assess the reliability of landmark identification on lateral cephalographs, 20 computed images, taken at 30 per cent reduced radiation (70 kV, 15 mA, 0.35 s) were compared to 20 conventional images (70 kV, 15 mA, 0.5 s). The 40 lateral cephalographs were taken from 20 orthodontic patients at immediate post-treatment and 1 year after retention. The order and type of imaging was randomized. Five orthodontists identified eight skeletal, four dental and five soft tissue landmarks on each of the 40 films. The error of identification was analysed in the XY Cartesian co-ordinate following digitization. Skeletal landmarks exhibited characteristic dispersion with respect to the Cartesian co-ordinates. Root apices were more variable than crown tips. Soft tissue landmarks were more consistent in the X co-ordinate. Two-way ANOVA shows that there is no significant difference between the two imaging systems in both co-ordinates (P > 0.05). Moreover, the differences are generally small (< 0.5 mm), and are unlikely to be of clinical significance. Most of the variables attained statistical power of at least 0.8 in the X-co-ordinate while only the dental landmarks achieved statistical power of at least 0.78 in the Y-co-ordinate. Based on the results of the study: (1) computed lateral cephalographs can be taken at 30 per cent radiation reduction, compared to conventional lateral cephalograph; (2) each anatomical landmark exhibits its characteristic dispersion of error in both the Cartesian co-ordinates; (3) there is no trend between the two imaging systems, with equivocal result, and none of the landmarks attained statistical significance when both raters and imaging systems are considered as factorial variables; (4) the random error of raters in landmark identification after replicate tracing was highlighted and needs to be taken into consideration in all studies involving landmark identification.
Adolescent↗
The utility of cephalometry with the Muller maneuver in evaluating the upper airway and its surrounding structures in Chinese patients with sleep-disordered breathing.
OBJECTIVE: The objective was to simultaneously measure the size and collapsibility of the upper airway in Chinese patients with sleep-disordered breathing using cephalometry with the Muller maneuver. STUDY DESIGN: Prospective study of 100 consecutive Chinese patients evaluated for sleep-disordered breathing at a sleep center. METHODS: Each patient received overnight polysomnography and two lateral cephalograms (at the end-expiration phase and the Muller maneuver, respectively) to evaluate the upper airway and its surrounding structures (soft palate, tongue, and hyoid bone). After excluding 15 subjects from this study because of unclear cephalograms, 85 patients with sleep-disordered breathing were enrolled, including 32 with snoring or mild obstructive sleep apnea and 53 with moderate to severe obstructive sleep apnea. RESULTS: Patients with varying degrees of severity of sleep-disordered breathing significantly differed in terms of the structure and function of the upper airway and the surrounding structures. The Muller maneuver may result in dynamic changes in the retropalatal airway and pharyngeal length, and the levels of dynamic changes were related to the severity of sleep-disordered breathing. Pearson correlation analysis revealed that the decrease in the minimum retropalatal dimension during the Muller maneuver in patients with snoring or with mild obstructive sleep apnea was related to the thickening of the soft palate and posterior displacement of tongue. Meanwhile, the decrease in the minimum retropalatal dimension in patients with moderate to severe obstructive sleep apnea was related to lengthening of the soft palate, increased tongue height, and downward displacement of the tongue and hyoid bone. CONCLUSION: Cephalometry with the Muller maneuver may provide further insight into the pathogenesis of various levels of severity of sleep-disordered breathing.
Adolescent↗
Dolichocephaly--a source of error in serial cephalometry.
Two patients are presented in whom ultrasonic cephalometry suggested intrauterine fetal growth retardation. The respective newborn infants were normally grown and had dolichocephaly with a normal head circumference. Dolichocephaly should be considered when cephalometry alone suggests a diagnosis of placental insufficiency.
Adult↗
Comparison of ultrasound cephalometry, radiology, and liquor studies in patients with unknown confinement dates.
The accuracy of predicting fetal maturity by ultrasound cephalometry, radiology, and liquor studies in patients with unknown confinement dates has been compared. The best prediction was given by ultrasound cephalometry. Liquor studies were least helpful.
Amniocentesis↗
Somnofluoroscopy, computed tomography, and cephalometry in the assessment of the airway in obstructive sleep apnoea.
BACKGROUND: Assessments of the upper airways in patients with the obstructive sleep apnoea syndrome are usually carried out on awake patients who are upright. The dynamics of the airway in a patient who is asleep and lying down may be different. METHODS: Somnofluoroscopy, computed tomography of the upper airway, and cephalometry were carried out in 11 patients with the obstructive sleep apnoea syndrome (10 male; mean (SD) age 53 (10) years) to examine the airway while they were awake and asleep. RESULTS: At somnofluoroscopy 10 patients were in stage 2 sleep and only one in REM sleep. At least five obstructive events were visualised by lateral fluoroscopy in each patient. Imaging allowed observation of the dynamics of airway collapse, which began in the oropharynx in all cases, progressing to the hypopharynx in 10 cases and to the laryngopharynx in five. At fluoroscopy the soft palate was seen to hook up during airway occlusion in 10 patients, thereby increasing its cross sectional area. It was then sucked down into the hypopharynx. Somnofluoroscopic and cephalometric findings agreed, eight of the 10 patients with hypopharyngeal collapse shown by somnofluoroscopy having an inferiorly placed hyoid bone according to cephalometry (distance from the mandibular plane to the hyoid bone (MP-H distance) increased); the one patient with no hypopharyngeal collapse had a normal MP-H. By contrast, six of the 11 patients had a normal or supranormal hypopharyngeal cross sectional area of the airway on the computed tomogram. CONCLUSIONS: Somnofluoroscopy allows examination of the dynamics of airway closure in this disorder and shows the important role of the soft palate in acting as a plug in the oropharynx. Dynamic studies are required to determine the pattern of pharyngeal obstruction in obstructive sleep apnoea.
Adult↗
[Serial determinations of serum oxytocinase and ultrasonic biparietal cephalometry in normal and high-risk pregnancies].
The value of sonor biparietal cephalometry and serum oxytocinase that we have obtained with weekly simultaneous determinations in 14 females with normal pregnancy and in 5 with pathological pregnancy, from 24th to 39th week, show a statical positive relation. Serum oxitocinase determination against hormonal tests of the phetoplancental function (urinary oestriol, pregnandiol, serum HCS, ecc.) give advantages: it is the easyer, faster and less espandove determination. Therefore we think that it is helpful to determin togheter serial values of sonar biparietal cephalometry and serum oxytocinase to anticipate the endouterine fetal growth retardation.
Aminopeptidases↗
Facial anthropometrics versus cephalometry as predictors for surgical treatment in patients with Class III dentofacial deformities.
The purpose of this study was to determine statistically the relative importance of facial anthropometrics and cephalometry in diagnosing the specific jaw deformity in patients with Class III relationships, ie, the contribution that maxillary deficiency and/or mandibular prognathism made to the Class III deformity. Frontal and right profile photographic views and pretreatment lateral cephalometric radiographs of 20 randomly selected Class III patients were analyzed. Correlation and multiple-regression analyses were utilized to determine the relative importance of clinical diagnosis and cephalometric diagnosis in determining the actual surgery performed. In addition, these analyses determined the relative importance of the various facial anthropometrics and cephalometric parameters critical to making the specific diagnosis of maxillary deficiency and/ or mandibular prognathism. It was concluded that a jaw-specific diagnosis of the Class III population studied was best made with facial anthropometrics rather than cephalometry, and the most important predictive facial features on which to based this diagnosis were paranasal configuration and chin projection. Although the overall cephalometric diagnosis had no statistically significant correlation to the actual surgery preformed, two individual cephalometric parameters, maxillary first molar to pterygoid vertical and mandibular plane angle, were found to statistically correlate to the actual surgery performed. These cephalometric parameters should be scrutinized along with the facial anthropometric data when the jaw-specific surgery is selected.
Anthropometry↗
Image processing for craniofacial landmark identification and measurement: a review of photogrammetry and cephalometry.
Facial surface anthropometry and cephalometry have been used for many years for the diagnosis of malformations, surgical planning and evaluation, and growth studies. These disciplines rely on the identification of craniofacial landmarks. Methods for 3D reconstruction of landmarks have been introduced, as have image processing algorithms for the automation of landmark extraction. This paper reviews facial surface anthropometry and cephalometry with reference to the image processing algorithms that have been applied and their effectiveness.
Algorithms↗