The hip radiographic magnification correlates with patient’s BMI

Objective. Obese patients have a higher prevalence of total hip arthroplasty (THA) and they are likely to experience a higher rate of pre-operative and post-operative complications. Pre-operative templating is a standard method of THA planning aiming to minimize the risk of complications. The accuracy of pre-operative templating depends on the knowledge of radiographic magnification factor. Whether and to what extent obesity affects radiographic magnification is not well described in literature. The purpose of this study was to determine whether obesity type affects hip radiographic magnification and quantify the relationship between the obesity measured and change in radiographic magnification. Materials and Methods. Digital radiographs of 303 patients who underwent THA were taken from clinical archives. The size of implanted femoral head was taken as an internal calibration marker to estimate hip radiographic magnification. Patients were stratified into obesity categories by body mass index (BMI). Patients’ mass, BMI, and body surface area (BSA) were studied as predictors of hip magnification. Results. There is a significant effect of obesity type on hip radiographic magnification (one-way ANOVA, p<0.001). The radiographic magnification correlates with patients’ mass (r=0.443, p<0.001), BMI (r=0.450, p<0.001) and BSA (r=0.443, p<0.001). For every 17 kg increase in patients’ mass, 5 kg/m2 increase in the BMI and for every 0.27 m2 in the BSA there is a 1 percent increase in the hip radiographic magnification. The increase in hip radiographic magnification with mass, BMI, and BSA is higher in females than in males. Conclusion. BMI could be used to estimate the increase in hip radiographic magnification due to obesity by adding 1% of magnification on average for each subsequent BMI category.

Evaluation and Comparison of Self-Made and Commercial Calibration Markers for Radiographic Magnification Correction in Veterinary Digital Radiography

Introduction Magnification error is always present in radiography and calibration is necessary, if high accuracy is required in pre-surgical planning. The goal of this study was to verify the use of self-made markers and calibration techniques and to establish guidelines for magnification correction. Methods We evaluated and compared spherical and linear markers of different sizes with focus on practicability, accuracy and precision. Markers were placed on foam pads or attached to flexible arms. Results Vertical marker deviation of 1 cm from the anatomical reference point corresponded to ∼1% of magnification error in our setting. Marker placement along the horizontal plane showed no significant magnification in the periphery of the radiograph. All markers showed good accuracy and the commercial spherical marker with a flexible segment arm had the best results regarding practicability. Discussion Our study suggests that marker type is not solely responsible for usability and accuracy but also the type of fixation. In the absence of a calibration marker, calculation of the magnification factor using a measurement tape during radiography is equally reliable. Use of a fixed averaged calculated calibration factor showed poor agreement compared with the marker calibration, probably due to variability in size of the animals. In conclusion, if precision matters, use of a calibration marker, which could be purchased or self-made, is advised.

Comparison of radiographic and tomographic evaluations for measurement of the Canal Flare Index in dogs

ABSTRACT The outcome of total hip arthroplasty (THA) in dogs is directly related to surgical planning. Templating of radiographs prior to THA should help the surgeon anticipate prosthesis size and femoral shape allowing canal fill of the proximal metaphysis by the implant ensuring primary stable fixation. The canal flare index (CFI) obtained from radiograph has been used as a measure of risk of complications for the technique in human beings and dogs. However, standard radiographs only provide limited data for the selection of cementless prostheses and the assessment of their fit within the femoral canal, due to factors like radiographic magnification and femoral rotation. Therefore, three-dimensional evaluation based on computed tomography (CT) may be a better tool for CFI measurement. The aim of this study was to compare anatomical measurement with CFI values obtained from craniocaudal radiography and CT. Craniocaudal radiographs using a horizontal radiographic beam (CR), CT, and anatomical macroscopic measurements (A) were obtained from 45 femurs from 23 canine cadavers. The differences between the values of CFI obtained from radiograph (CFI-R), computed tomography on transverse (CFI- TT) and longitudinal axis (CFI-TL) compared to the CFI obtained from macroscopic measurements - gold standard - (CFI-A), and 95% limits of agreement (LOA) between the values, were evaluated by the Bland-Altman method. Dimensions obtained from CT techniques had a greatest mean difference from anatomical and CFI values were also different (P=0.032). Under the experimental conditions, the craniocaudal radiograph, provided the most accurate measurement of the CFI (mean difference: 0.087 ± 0.42).

EVALUATION OF ECTOPIC ERUPTION IN TEETH’S OF CHILDRENS FROM 5 TO 12 YEARS AGE GROUP

Treatment is advised to guide the tooth into a more favorable path of eruption to minimize damage to affected dentition, preserve arch length, and to maintain function. Without intervention, sequelae can include premature loss of the anteriorly affected tooth, tipping and rotation of the ectopic molar, space loss and malocclusion. Treatment will depend upon the severity of the impaction. Mildly to moderately impacted molars can be guided easily with elastic orthodontic separators. More severe impactions require more complex treatment options, including potential extraction of the anteriorly affected tooth, removable or fixed appliances, or surgical uprighting. The present study was planned for evaluation of Evaluation of Ectopic Eruption in Teeth’s of Childrens from 5 to 12 Years Age Group. The present study was planned in Department of Orthodontics, Patna Dental College and Hospital, Patna. Total 50 childrens referred to Department of Orthodontics were evaluated for the ectopic eruptions. All the radiographs were compared in each patient, along all the usual followup time. To rule out the possibility of error due to radiographic magnification, the crown measurements in bitewing radiographs and in dental casts were compared, and no significant differences were present. Early intervention of ectopically erupting first permanent molars is very crucial to avoid complex orthodontic treatment later on. Ectopic eruption of individual teeth tend to occur as often bilaterally as unilaterally in the same arch, except for mandibular central incisors, first molars and mandibular canines. Early diagnosis and interception of ectopically erupting teeth will allow us in preventing more complicated malocclusions in future. Keywords: Eruption problems, Ectopic eruption, Permanent teeth, etc.

Analysis of feline splenic radiographic measurements and their correlation to ultrasonographic measurements

Objectives The purpose of this study was to establish a method for feline splenic measurement on abdominal radiographs and evaluate for correlation between the radiographic measurements and ultrasonographic measurements. Methods One hundred cats with normal abdominal radiographs and ultrasound (US) studies of the spleen were evaluated. The hypothesis was that the measurement of the spleen on the radiographs would correlate with the measurement of the spleen on US. The radiographic and ultrasonographic measurements were tabulated and compared using linear regression and t-tests using unequal variances. Results The measurement of the spleen on the ventrodorsal projection was characterized as one of three shapes (A, B or C), and thereby based on the thickest part of the spleen (when corrected for radiographic magnification: A = 9.9 ± 2.2 mm; B = 8.1 ± 1.8 mm; C = 8.0 ± 2.3 mm). There were 48 cats where the head of the spleenwas seen on the right lateral (n = 10), the left lateral (n = 24) or both (n = 14) projections. On one left lateral, both the head and tail of the spleen were seen. There was weak correlation between the radiographic and US measurements(R ⩼0.6). Splenic thickness of shape A on the ventrodorsal projection was significantly greater than categories B and C. Conclusions and relevance Radiographic measurement of the spleen is not a reliable indicator of its ultrasonographic measurement. The ultrasonographic measurements seen in this study (mean of 8.0 ± 1.6 mm) were similar to measurements of the spleen reported in previous studies. It is rare to see the tail of the spleen on lateral feline abdominal radiographs.

Digital templating for THA: a simple computer-assisted application for complex hip arthritis cases

Introduction:Total hip arthroplasty (THA) is the standard procedure for end-stage arthritis of the hip. Its technical success relies on preoperative planning of the surgical procedure and virtual setup of the operative performance. Digital hip templating is one methodology of preoperative planning for THA which requires a digital preoperative radiograph and a computer with special software.Patients and methods:This is a prospective study involving 23 patients (25 hips) who were candidates for complex THA surgery (unilateral or bilateral). Digital templating is done by radiographic assessment using radiographic magnification correction, leg length discrepancy and correction measurements, acetabular component and femoral component templating as well as neck resection measurement.Results:The overall accuracy for templating the stem implant’s exact size is 81%. This percentage increased to 94% when considering sizing within 1 size.Conclusion:Digital templating has proven effective, reliable and essential technique for preoperative planning and accurate prediction of THA sizing and alignment.

Evaluation of radiographic magnification in lateral cephalograms obtained with different X-ray devices: experimental study in human dry skull

OBJECTIVE: The purpose of this study was to evaluate the influence of the magnification factor of the radiographic image in angular, linear and proportional measurements. METHODS: From a dried human skull where metallic spheres with predetermined size were fixed (1.0 mm), 14 radiographs were obtained in devices of three different manufacturers: Panoura, Instrumentarium and Tomeceph. The Pearson correlation test was used to investigate the relationship between the rate of radiographic magnification and the cephalometric measurements assessed. RESULTS: According to the results, the linear measurements showed a high positive correlation, pointing out great influence of the magnification factor, while the angular and proportional measurements did not correlate. CONCLUSIONS: Comparisons between linear cephalometric measurements obtained with different devices from the same manufacturer showed maximum rates of expansion of 0.6%, 1.25% and 2.3%, respectively, for the devices from Instrumentarium (OP-100, Instrumentarium, Finland), Panoura (10CSU, Yoshida, Japan) and Satelec/Tomeceph (XMind, Satelec/Tomeceph Orion Corporation, Finland).

Radiography, 99mTc–HDP, and 111In Labeled Vitamin B12 SPECT of Canine Osteosarcoma: A Comparative Study

The objective of this article was to compare radiography, planar bone scintigraphy, and single-photon emission computed tomography (SPECT) to determine the size of osteosarcomas in long bones of dogs. Ten dogs with osteosarcoma in six radii, two humeri, one tibia, and one ulna were evaluated. Macroslides, mediolateral radiographs, planar scintigrams, and sagittal images from SPECT scans were used to obtain measurements. On the scintigraphic images, the edges of the tumor were established using the activity profile imaging tool. The radiographic magnification was factored. The mean percentage of tumor size overestimation was 9.29% on mediolateral radiographs, 5.35% on planar scintigrams, and 33.25% on SPECT images. The correlation coefficient adjusted for sample size was significantly higher (P&lt;0.01) for technetium 99m (99mTc) hydroxyethylene diphosphonate (HDP) (75.5%) and radiography (61.3%) compared with indium 111–vitamin B12 (28.3%). The correlation coefficient for 99mTc–HDP was higher than that obtained for radiographs; however, statistical difference between the two variables was not demonstrated (P&gt;0.05). 99mTc bone scan is a good estimator of intramedullary size of osteosarcoma in long bones when the activity profile tool to determine the margin of the tumor is used.