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Magnification of digital hip radiographs differs between clinical workplaces.

ABSTRACT: Preoperative planning for total hip arthroplasty includes templating on anteroposterior radiographs. It is necessary to consider radiographic magnification in order to scale templates accurately. Studies dealing with hip templating report different values of radiographic magnification. It is not clear if the observed difference in magnification between the studies is caused by variability in studied groups, methodology or instrumentation. We hypothesize that there is a difference in magnification between clinical workplaces. Within this study, radiographic magnification was estimated on 337 radiographs of patients after total hip surgery from five orthopaedic departments in the Czech Republic. Magnification was determined for each patient as a ratio between diameter of implanted femoral head measured on radiogram and its true size. One-way ANOVA revealed significant differences in magnification between workplaces (F(4,332) = 132, p?0.001). These results suggest that radiographic magnification depends on the workplace where it is taken or more precisely on radiographic device. It indicates potential limits in generalizability of results of studies dealing with preoperative planning accuracy to other institutions.

SUBMITTER: Hornova J

PROVIDER: S-EPMC5708766 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Magnification of digital hip radiographs differs between clinical workplaces.

Hornová Jana J Růžička Pavel P Hrubina Maroš M Šťastný Eduard E Košková Andrea A Fulín Petr P Gallo Jiří J Daniel Matej M

PloS one 20171130 11

Preoperative planning for total hip arthroplasty includes templating on anteroposterior radiographs. It is necessary to consider radiographic magnification in order to scale templates accurately. Studies dealing with hip templating report different values of radiographic magnification. It is not clear if the observed difference in magnification between the studies is caused by variability in studied groups, methodology or instrumentation. We hypothesize that there is a difference in magnificatio ...[more]

PMID: 29190787

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Project description:BACKGROUND:Accurate detection of gastric infection by Helicobacter pylori (H. pylori) and premalignant lesions are important for effective provision of treatment, preventing the development of gastric neoplasia. Optical enhancement systems with optical magnification improved the identification of mucosal superficial and vascular patterns in patients with dyspepsia. AIM:To evaluate an optical enhancement system with high-definition magnification, for diagnosis of normal gastric mucosa, H. pylori-associated gastritis, and gastric atrophy. METHODS:A cross-sectional, nonrandomized study from November 2015 to April 2016 performed in a single-tertiary academic center from Ecuador. Seventy-two consecutive patients with functional dyspepsia according to the Rome III criteria, were tested for H. pylori using a stool antigen test and were assigned to an Hp + group or an Hp - control group. Esophagogastroduodenoscopy with high-definition optical magnification and digital chromoendoscopy was performed, and patients were classified into 4 groups, in accordance to the microvascular-architecture pattern of the mucosa. Interobserver and intraobserver agreement among operators were calculated. RESULTS:Of the 72 participants, 35 were Hp + and 37 were Hp -. Among 10 patients with normal mucosal histology in biopsy samples, 90% had a Type I pattern of microvascular architecture by endoscopy. Among participants with type IIa and type IIb patterns, significantly more were Hp+ than Hp- (32 vs 8), and most (31 out of 40) had histological diagnoses of chronic active gastritis. Two of the three participants with a histological diagnosis of atrophy had a type III microvascular pattern. The type I pattern predicted normal mucosa, type IIa-IIb predicted H. pylori infection, and type III predicted atrophy with sensitivities of 90.0%, 91.4%, and 66.7%, respectively. The intraobserver and interobserver agreements had kappa values of 0.91 and 0.89, respectively. CONCLUSION:High-definition optical magnification with digital chromoendoscopy is useful for diagnosis of normal gastric mucosa and H. pylori-associated gastritis with high accuracy, but further studies are needed to determine whether endoscopic diagnosis of gastric atrophy is feasible.

Project description:ObjectivesTo compare ultra-low-dose CT (ULD-CT) of the osseous pelvis with tin filtration to standard clinical CT (CT), and to assess the quality of computed virtual pelvic radiographs (VRs).MethodsCT protocols were optimized in a phantom and three pelvic cadavers. Thirty prospectively included patients received both standard CT (automated tube voltage selection and current modulation) and tin-filtered ULD-CT of the pelvis (Sn140kV/50mAs). VRs of ULD-CT data were computed using an adapted cone beam-based projection algorithm and were compared to digital radiographs (DRs) of the pelvis. CT and DR dose parameters and quantitative and qualitative measures (1 = worst, 4 = best) were compared. CT and ULD-CT were assessed for osseous pathologies.ResultsDose reduction of ULD-CT was 84% compared to CT, with a median effective dose of 0.38 mSv (quartile 1-3: 0.37-0.4 mSv) versus 2.31 mSv (1.82-3.58 mSv; p < .001), respectively. Mean dose of DR was 0.37 mSv (± 0.14 mSv). The median signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of bone were significantly higher for CT (64.3 and 21.5, respectively) compared to ULD-CT (50.4 and 18.8; p ≤ .01), while ULD-CT was significantly more dose efficient (figure of merit (FOM) 927.6) than CT (FOM 167.6; p < .001). Both CT and ULD-CT were of good image quality with excellent depiction of anatomy, with a median score of 4 (4-4) for both methods (p = .1). Agreement was perfect between both methods regarding the prevalence of assessed osseous pathologies (p > .99). VRs were successfully calculated and were equivalent to DRs.ConclusionTin-filtered ULD-CT of the pelvis at a dose equivalent to standard radiographs is adequate for assessing bone anatomy and osseous pathologies and had a markedly superior dose efficiency than standard CT.Key points• Ultra-low-dose pelvic CT with tin filtration (0.38 mSv) can be performed at a dose of digital radiographs (0.37 mSv), with a dose reduction of 84% compared to standard CT (2.31 mSv). • Tin-filtered ultra-low-dose CT had lower SNR and CNR and higher image noise than standard CT, but showed clear depiction of anatomy and accurate detection of osseous pathologies. • Virtual pelvic radiographs were successfully calculated from ultra-low-dose CT data and were equivalent to digital radiographs.

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Magnification of digital hip radiographs differs between clinical workplaces.

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Magnification of digital hip radiographs differs between clinical workplaces.

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