Tomosynthesis: A new radiologic technique for rapid diagnosis of scaphoid fractures

An Umbrella Review and Updated Meta-Analysis of Imaging Modalities in Occult Scaphoid and Hip and Femoral Fractures

Background: Occult fractures may cause multiple morbidities. If occult fractures were detected earlier, complications may be preventable. This umbrella review and updated meta-analysis will aim to evaluate the use of imaging modalities in detecting occult scaphoid and hip fractures. Methods: The protocol for this study is available in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42024525388). The literature search started and ended on 17 March 2024. We searched seven academic databases: MEDLINE, Cochrane Library, Pubmed, Science Direct, Google Scholar, WHO International Clinical Trials Registry Platform, and The Joanna Briggs Institute (JBI) database. The meta-analysis was conducted with the STATA program using the "midas" command. Results: There are four systematic reviews evaluating occult hip and femoral fractures with 6174 patients and two reviews evaluating occult scaphoid fractures with 1355 patients. The prevalence of occult scaphoid fracture and occult hip and femoral fractures is 23.87% (95% CI 18.25-29.49) and 44.8% (95% CI 39.38-51.4), respectively. Magnetic resonance imaging (MRI) had the best posterior probability of positive likelihood ratio (LR+) with 95% and 96% and negative likelihood ratio (LR-) with 0.15% and 1% for both occult scaphoid and hip fractures, respectively, assuming a 25% baseline. MRI could both confirm and exclude occult hip fractures while it can only confirm occult scaphoid fractures. Bone scans are inappropriate for either type of occult fractures The level of evidence for occult scaphoid fracture is weak while it is suggestive for occult hip fractures. Conclusion: The findings strengthen the use of MRI after an initially negative radiograph fracture for occult hip and femoral fractures, with a CT scan as a viable second option.

A Novel Quantitative Evaluation of Bone Formation After Opening Wedge High Tibial Osteotomy Using Tomosynthesis

This study aimed to establish and validate a novel evaluation method using digital tomosynthesis to quantify bone formation in the gap after opening wedge high tibial osteotomy (OW-HTO). We retrospectively analyzed bone formation in the gap in 22 patients who underwent OW-HTO using digital tomosynthesis at 1, 2, 3, 6, 9, and 12 months postoperatively. Bone formation was semi-quantitatively assessed using the modified van Hemert's score and density measurements on digital tomosynthesis images. The gap filling value (GFV) was calculated as the ratio of the intensities of the opening gap and the tibial shaft. In addition, the relationship between the modified van Hemert's score and GFV was evaluated. The reproducibility of GFV had an interclass correlation coefficient (ICC [1,2]) of 0.958 for intraobserver reliability and an ICC (2,1) of 0.975 for interobserver reliability. The GFV increased in a time-dependent manner and was moderately correlated with the modified van Hemert's score (r = 0.630, p < 0.001). The GFV plateaued at 6 months postoperatively. In addition, the GFV was higher in patients with a modified van Hemert's score of 2 than in patients with a modified van Hemert's score of 3 (p = 0.008). The GFVs obtained using digital tomosynthesis can be used to assess postoperative bone formation in the opening gap after OW-HTO with high accuracy and reproducibility.

Diagnosis of Suspected Scaphoid Fractures

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Suspected scaphoid fractures are a diagnostic and therapeutic challenge despite the advances in knowledge regarding these injuries and imaging techniques. The risks and restrictions of routine immobilization as well as the restriction of activities in a young and active population must be weighed against the risks of nonunion that are associated with a missed fracture.

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The prevalence of true fractures among suspected fractures is low. This greatly reduces the statistical probability that a positive diagnostic test will correspond with a true fracture, reducing the positive predictive value of an investigation.

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There is no consensus reference standard for a true fracture; therefore, alternative statistical methods for calculating sensitivity, specificity, and positive and negative predictive values are required.

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Clinical prediction rules that incorporate a set of demographic and clinical factors may allow stratification of secondary imaging, which, in turn, could increase the pretest probability of a scaphoid fracture and improve the diagnostic performance of the sophisticated radiographic investigations that are available.

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Machine-learning-derived probability calculators may augment risk stratification and can improve through retraining, although these theoretical benefits need further prospective evaluation.

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Convolutional neural networks (CNNs) are a form of artificial intelligence that have demonstrated great promise in the recognition of scaphoid fractures on radiographs. However, in the more challenging diagnostic scenario of a suspected or so-called "clinical" scaphoid fracture, CNNs have not yet proven superior to a diagnosis that has been made by an experienced surgeon.

Point-of-Care Tomosynthesis Imaging of the Wrist

INTRODUCTION

Musculoskeletal injury to extremities is a common issue for both stateside and deployed military personnel, as well as the general public. Superposition of anatomy can make diagnosis difficult using standard clinical techniques. There is a need for increased diagnostic accuracy at the point-of-care for military personnel in both training and operational environments, as well as assessment during follow-up treatment to optimize care and expedite return to service. Orthopedic tomosynthesis is rapidly emerging as an alternative to digital radiography (DR), exhibiting an increase in sensitivity for some clinical tasks, including diagnosis and follow-up of fracture and arthritis. Commercially available digital tomosynthesis systems are large complex devices. A compact device for extremity tomosynthesis (TomoE) was previously demonstrated using carbon nanotube X-ray source array technology. The purpose of this study was to prepare and evaluate the prototype device for an Institutional Review Board-approved patient wrist imaging study and provide initial patient imaging results.

MATERIALS AND METHODS

A benchtop device was constructed using a carbon nanotube X-ray source array and a flat panel digital detector. Twenty-one X-ray projection images of cadaveric specimens and human subjects were acquired at incident angles from -20 to +20 degrees in various clinical orientations, with entrance dose calibrated to commercial digital tomosynthesis wrist scans. The projection images were processed with an iterative reconstruction algorithm in 1 mm slices. Reconstruction slice images were evaluated by a radiologist for feature conspicuity and diagnostic accuracy.

RESULTS

The TomoE image quality was found to provide more diagnostic information than DR, with reconstruction slices exhibiting delineation of joint space, visual conspicuity of trabecular bone, bone erosions, fractures, and clear depiction of normal anatomical features. The scan time was 15 seconds and the skin entrance dose was verified to be 0.2 mGy.

CONCLUSIONS

The TomoE device image quality has been evaluated using cadaveric specimens. Dose was calibrated for a patient imaging study. Initial patient images depict a high level of anatomical detail and an increase in diagnostic value compared to DR.

Has NICE guidance changed the management of the suspected scaphoid fracture: A survey of UK practice

INTRODUCTION

Despite scaphoid fractures being relatively uncommon pro-active treatment of suspected fractures has been seen as a risk management strategy. The poor positive predictive value of X-rays has led to published guidelines advocating MRI as a first-line or early imaging tool. It is unclear whether UK hospitals have been able to introduce early scanning and this national survey sought to establish the current management strategies for patients with a suspected scaphoid fracture.

METHOD

An electronic survey of UK emergency departments (ED) was conducted to establish the initial and follow up strategies for patients with negative imaging. Comparison of first and second-line imaging modalities was undertaken together with review of the clinical speciality responsible for ongoing management.

RESULTS

166 UK NHS Trusts were identified with emergency department facilities of which 66 (39.8%) responded. All sites perform an X-ray as the initial examination. For those with a negative examination ED follow up was the most common approach (54.6%), although many sites refer patients to other specialities including orthopaedics (39.4%) for follow up. The data demonstrated inconsistencies in the number of follow-up episodes and the different imaging investigations utilised. Frustration with the challenges presented by this patient cohort was evident.

CONCLUSION

The suspected scaphoid fracture represents an ongoing challenge to the NHS with many resource intensive pathways reliant on access to complex imaging investigations.

IMPLICATIONS FOR PRACTICE

Our study identified that UK Emergency Departments have limited early access to complex imaging for scanning of the scaphoid. A range of strategies are used for follow up of suspected scaphoid fractures and these are resource intensive. Overtreatment of patients with suspected scaphoid fracture is used as a risk management approach.

[Clinical and imaging methods in diagnostics of scaphoid fracture and non-union]

Clinical and radiological diagnostics are the base of a differentiated treatment of carpal disorders. With special regard to diagnostics of the scaphoid, not only the choice and the correct implementation of the imaging methods are crucial, but also their methodical limitations have to be taken into account. No other common fracture is more often undiagnosed, because neglected or overlooked. Concomitantly, delayed or untreated scaphoid fractures require demanding therapies in the sequel and may lead to functional restrictions in the long-term. This review article aims to discuss the clinical and imaging diagnostics for scaphoid fractures and non-union.

Improved diagnostic confidence and accuracy of pediatric elbow fractures with digital tomosynthesis

BACKGROUND

Pediatric elbow fractures are common but remain challenging to accurately diagnose. Digital tomosynthesis is a technique that has shown promise in difficult adult fracture patterns but has not been formally studied in the pediatric population.

OBJECTIVE

To assess the added value of digital tomosynthesis on the detection and diagnostic confidence of pediatric elbow fractures.

MATERIALS AND METHODS

A retrospective study was performed between January 2016 and December 2017 in pediatric patients (≤18 years) to assess the ability of conventional elbow radiographs and digital tomosynthesis to detect elbow fractures. One hundred twenty-one pediatric patients with concern for pediatric elbow trauma (64 males, 57 females; mean age: 8.1 years, range: 1 year to 17 years) were imaged with both conventional elbow radiographs and digital tomosynthesis. Two blinded pediatric radiologists identified fractures and indicated their diagnostic confidence. Observer agreement was assessed with Cohen's Kappa coefficient and a nonparametric Wilcoxon rank sum test was used to compare the degree of diagnostic confidence between standard radiographs alone and standard radiographs with digital tomosynthesis. McNemar's test was used to assess the difference in the rate of fracture detection between the two methods and sensitivity, specificity, precision, accuracy and diagnostic odds ratios were calculated.

RESULTS

Compared with standard radiographs alone, standard radiographs with digital tomosynthesis improved inter-rater agreement, sensitivity, specificity, accuracy, precision and the diagnostic odds ratio for fracture detection and increased diagnostic confidence (Rater 1: P=0.01, Rater 2: P=0.003).

CONCLUSION

The addition of digital tomosynthesis with conventional elbow radiographs improves diagnostic confidence and performance for the detection of pediatric elbow fractures.

Digital tomosynthesis of the pediatric elbow

Imaging pediatric elbow trauma in the acute setting remains diagnostically challenging given difficult patient positioning, multiple ossification centers of the pediatric elbow, overlapping structures, and complex joint anatomy. Digital tomosynthesis is a technique where the X-ray source travels across a limited arc angle, obtaining a series of low-dose exposures that are in turn digitally reconstructed to produce high in-plane resolution at a relatively low overall radiation dose. Digital tomosynthesis is now more commonly integrated into standard radiographic machines and offers a new and exciting way to assess the pediatric elbow. In this review article we discuss the clinical applications of digital tomosynthesis in pediatric elbow trauma along with challenges related to technique, patient positioning and artifacts.