Postoperative Extremity Tomosynthesis-A Superimposition-Free Alternative to Standard Radiography?

RATIONALE AND OBJECTIVES

This study investigates the performance of tomosynthesis in the presence of osteosynthetic implants, aiming to overcome superimposition-induced limitations in conventional radiograms.

MATERIALS AND METHODS

After surgical fracture induction and subsequent osteosynthesis, 8 cadaveric fracture models (wrist, metacarpus, ankle, metatarsus) were scanned with the prototypical tomosynthesis mode of a multiuse x-ray system. Tomosynthesis protocols at 60, 80, and 116 kV (sweep angle 10°, 13 FPS) were compared with standard radiograms. Five radiologists independently rated diagnostic assessability based on an equidistant 7-point scale focusing on fracture delineation, intra-articular screw placement, and implant positioning. The intraclass correlation coefficient (ICC) was calculated to analyze interrater agreement.

RESULTS

Radiation dose in radiography was 0.48 ± 0.26 dGy·cm2 versus 0.12 ± 0.01, 0.36 ± 0.02, and 1.95 ± 0.11 dGy·cm2 for tomosynthesis scans at 60, 80, and 116 kV. Delineation of fracture lines was superior for 80/116 kV tomosynthesis compared with radiograms (P ≤ 0.003). Assessability of intra-articular screw placement was deemed favorable for all tomosynthesis protocols (P ≤ 0.004), whereas superiority for evaluation of implant positioning could not be ascertained (all P's ≥ 0.599). Diagnostic confidence was higher for 80/116 kV tomosynthesis versus radiograms and 60 kV tomosynthesis (P ≤ 0.002). Interrater agreement was good for fracture delineation (ICC, 0.803; 95% confidence interval [CI], 0.598-0.904), intra-articular screw placement (ICC, 0.802; 95% CI, 0.599-0.903), implant positioning (ICC, 0.855; 95% CI, 0.729-0.926), and diagnostic confidence (ICC, 0.842; 95% CI, 0.556-0.934).

CONCLUSIONS

In the postoperative workup of extremity fractures, tomosynthesis allows for superior assessment of fracture lines and intra-articular screw positioning with greater diagnostic confidence at radiation doses comparable to conventional radiograms.

ACR Appropriateness Criteria® Chronic Extremity Joint Pain-Suspected Inflammatory Arthritis, Crystalline Arthritis, or Erosive Osteoarthritis: 2022 Update

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity because there is significant overlap of imaging findings among the various types of arthritis. This document provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

A novel few-views arrangement of the fixed X-ray tubes for tomosynthesis

PURPOSE

Tomosynthesis is a technique that reconstructs a volume image from limited-angle projection data. In conventional tomosynthesis, the examination time is long, so it can be difficult for patients to hold their breath during certain examinations, such as chest imaging. Few-views tomosynthesis, which uses a linear arrangement of fixed X-ray tubes and enables an image to be obtained within 1 s, was found to be useful in the clinical setting in our previous study. In the present study, we attempted to develop a novel few-views tomosynthesis system that can obtain images with an improved image quality.

METHODS

A novel few-views arrangement of X-ray tubes was proposed and the image reconstruction method with regularization term was applied. The linear arrangement was used for the X-ray tube arrangement in our previous few-views tomosynthesis, in contrast, a circular arrangement was proposed in this study. The validation of this system was conducted with a numerical simulation and a real data experiment.

RESULTS

The wider the scan angle, the more the object shadow spreads from "in-plane", allowing for artifact suppression. In the circular arrangement, the constant scan angle of θ is used, but in the linear arrangement the scan angle is set from 0 to θ. The artifacts in "out-of-plane" were more strongly suppressed in the circular arrangement than in the linear arrangement.

CONCLUSIONS

Artifacts spreading in the z-direction were more strongly suppressed using the circular arrangement than the linear arrangement. Therefore, the circular arrangement was deemed appropriate for few-views tomosynthesis.

Comparative evaluation of tomosynthesis, computed tomography, and magnetic resonance imaging findings for metacarpophalangeal joints from equine cadavers

OBJECTIVE

To describe the technique and assess the diagnostic potential and limitations of tomosynthesis for imaging of the metacarpophalangeal joint (MCPJ) of equine cadavers; compare the tomosynthesis appearance of pathological lesions with their conventional radiographic, CT, and MRI appearances; and evaluate all imaging findings with gross lesions of a given MCPJ.

SAMPLE

Distal portions of 4 forelimbs from 4 equine cadavers.

PROCEDURES

The MCPJs underwent radiography, tomosynthesis (with a purpose-built benchtop unit), CT, and MRI; thereafter, MCPJs were disarticulated and evaluated for the presence of gross lesions. The ability to identify pathological lesions on all images was assessed, followed by semiobjective scoring for quality of the overall image and appearance of the subchondral bone, articular cartilage, periarticular margins, and adjacent trabecular bone of the third metacarpal bone, proximal phalanx, and proximal sesamoid bones of each MCPJ.

RESULTS

Some pathological lesions in the subchondral bone of the third metacarpal bone were detectable with tomosynthesis but not with radiography. Overall, tomosynthesis was comparable to radiography, but volumetric imaging modalities were superior to tomosynthesis and radiography for imaging of subchondral bone, articular cartilage, periarticular margins, and adjacent bone.

CONCLUSIONS AND CLINICAL RELEVANCE

With regard to the diagnostic characterization of equine MCPJs, tomosynthesis may be more accurate than radiography for identification of lesions within subchondral bone because, in part, of its ability to reduce superimposition of regional anatomic features. Tomosynthesis may be useful as an adjunctive imaging technique, highlighting subtle lesions within bone, compared with standard radiographic findings.

Digital Tomosynthesis versus Conventional Radiography for Evaluating Osteonecrosis of the Femoral Head

Objective

The aim of this study was to compare the diagnostic performances of digital tomosynthesis (DTS) and conventional radiography in detecting osteonecrosis of the femoral head (ONFH) using computed tomography (CT), as the reference standard and evaluate the diagnostic reproducibility of DTS.

Materials and Methods

Forty-five patients (24 male and 21 female; age range, 25–77 years) with clinically suspected ONFH underwent anteroposterior radiography, DTS, and CT. Two musculoskeletal radiologists independently evaluated the presence and type of ONFH. The diagnostic performance of radiography and DTS in detecting the presence of ONFH and determining the types of ONFH were evaluated. The interobserver and intraobserver reliabilities of each imaging modality were analyzed using Cohen's kappa.

Results

DTS had higher sensitivity (89.4%–100% vs. 74.5%–76.6%) and specificity (97.3%–100% vs. 78.4%–83.8%) for ONFH detection than radiography. DTS showed higher performance than radiography in identifying the subtypes of ONFH with statistical significance in one reader (type 1, 100% vs. 30.8%, p = 0.004; type II, 97.1% vs. 73.5%, p = 0.008). The interobserver agreement was excellent for DTS and moderate for radiography (kappa of 0.86 vs. 0.57, respectively). The intraobserver agreement for DTS was higher than that of radiography (kappa of 0.96 vs. 0.69, respectively).

Conclusion

DTS showed higher diagnostic performance and reproducibility than radiography in detecting ONFH. DTS may be used as a first-line diagnostic modality instead of radiography for patients suspected of having ONFH.

Diagnostic performance of tomosynthesis for evaluation of bone tumors and tumor-like lesions: a comparison with radiography

BACKGROUND

Even though radiologic diagnosis of bone tumors and tumor-like lesions is usually based on radiographs, radiographically faint imaging features sometimes remain challenging due to overlapping anatomical structures.

PURPOSE

To compare tomosynthesis with radiography for the evaluation of bone tumors and tumor-like lesions.

MATERIAL AND METHODS

Forty-seven bone tumors and tumor-like lesions were assessed with radiographs and tomosynthesis images. Two radiologists independently analyzed imaging features of lesions, including margin, periosteal reaction, cortical thinning, matrix mineralization, cortical destruction (such as pathologic fracture), and extraosseous soft-tissue extension. Computed tomography (CT) imaging was used as a reference method. Diagnostic performances of radiography and tomosynthesis were analyzed and compared based on sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Effective radiation dose was compared among the three imaging modalities by phantom studies.

RESULTS

Inter-observer variability (kappa value) for imaging features was slight to moderate on radiography (0.167-0.588), whereas it was nearly perfect on tomosynthesis (0.898-1.000) except for extraosseous soft-tissue extension (0.647 vs. 0.647). Tomosynthesis showed significantly higher sensitivity than radiography in evaluating the margin for bone tumors or tumor-like lesions (1.00 vs. 0.85; P = 0.016), and significantly higher accuracy than radiography in evaluating the margin and matrix mineralization for those (1.00 vs. 0.85; P = 0.016 and 0.91 vs.0.77; P = 0.023, respectively). In phantom studies, mean effective radiation doses were highest in order of CT, tomography, and radiography.

CONCLUSION

Tomosynthesis increases sensitivity and accuracy of the margin as well as accuracy of the matrix mineralization of bone tumors and tumor-like lesions compared to radiography.

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.

Bone health assessment via digital wrist tomosynthesis in the mammography setting

Bone fractures attributable to osteoporosis are a significant problem. Though preventative treatment options are available for individuals who are at risk of a fracture, a substantial number of these individuals are not identified due to lack of adherence to bone screening recommendations. The issue is further complicated as standard diagnosis of osteoporosis is based on bone mineral density (BMD) derived from dual energy x-ray absorptiometry (DXA), which, while helpful in identifying many at risk, is limited in fully predicting risk of fracture. It is reasonable to expect that bone screening would become more prevalent and efficacious if offered in coordination with digital breast tomosynthesis (DBT) exams, provided that osteoporosis can be assessed using a DBT modality. Therefore, the objective of the current study was to explore the feasibility of using digital tomosynthesis imaging in a mammography setting. To this end, we measured density, cortical thickness and microstructural properties of the wrist bone, correlated these to reference measurements from microcomputed tomography and DXA, demonstrated the application in vivo in a small group of participants, and determined the repeatability of the measurements. We found that measurements from digital wrist tomosynthesis (DWT) imaging with a DBT scanner were highly repeatable ex vivo (error = 0.05%-9.62%) and in vivo (error = 0.06%-10.2%). In ex vivo trials, DWT derived BMDs were strongly correlated with reference measurements (R = 0.841-0.980), as were cortical thickness measured at lateral and medial cortices (R = 0.991 and R = 0.959, respectively) and the majority of microstructural measures (R = 0.736-0.991). The measurements were quick and tolerated by human patients with no discomfort, and appeared to be different between young and old participants in a preliminary comparison. In conclusion, DWT is feasible in a mammography setting, and informative on bone mass, cortical thickness, and microstructural qualities that are known to deteriorate in osteoporosis. To our knowledge, this study represents the first application of DBT for imaging bone. Future clinical studies are needed to further establish the efficacy for diagnosing osteoporosis and predicting risk of fragility fracture using DWT.

The use of digital tomosynthesis in rheumatology: a systematic review of the literature focused on four diseases

BACKGROUND AND AIMS

Digital tomosynthesis has proven useful in the evaluation of damage to joints. This study aims to describe the most common digital tomosynthesis findings for four rheumatological entities and to compare the usefulness of this technique with that of other imaging techniques.

MATERIALS AND METHODS

Following the PRISMA guidelines, we systematically searched the literature for articles about the use of digital tomosynthesis in rheumatoid arthritis, osteoarthritis, spondyloarthritis, and gout. We used the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) criteria to evaluate the quality of the articles included.

RESULTS

We included 13 articles. For rheumatoid arthritis, osteoarthritis, and spondyloarthritis, digital tomosynthesis detected bone abnormalities better than plain-film X-rays; however, for gout, the results were variable.

CONCLUSIONS

Digital tomosynthesis can play an important role in the evaluation of skeletal abnormalities in rheumatological disease, especially compared to plain-film X-rays.

Variations in slice sensitivity profile for various height settings in tomosynthesis imaging: Phantom study

Understanding the properties of slice sensitivity profile (SSP), or slice thickness, is crucial for an accurate and highly reproducible diagnosis using tomosynthesis imaging. The objectives of the present study are therefore to quantitatively evaluate how the SSP with the use of a small metal bead is affected by different settings of the height from the table and the height of the center of rotation (COR) in tomosynthesis imaging except for the digital breast tomosynthesis, and visually verify the effects on tomosynthesis images. The reconstruction filters used were three types of filtered back-projection and iterative reconstructions. The SSP was measured from the full width at half maximum (FWHM-SSP) of the profile curve of the bead in the perpendicular direction (z direction) relative to the table. Two types of anthropomorphic phantoms simulating the human body, with bones and soft tissues, were used to study the effects of different settings for the COR height. In all reconstruction filters, the FWHM-SSP changed as the height of the bead varied when the bead and COR were set to the same height from the table. If the bead and the COR were set to different heights, the FWHM-SSP increased (decreased) when the height of the bead was set to be greater (less) than the height of the COR. These changes were also confirmed on the anthropomorphic phantom images of the bones and soft tissues.

The Diagnostic Reproducibility of Tomosynthesis for the Correlation between Acromiohumeral Distance and Rotator Cuff Size or Type

Objective

To correlate the acromiohumeral distance (AHD) using tomosynthesis and rotator cuff (RC) pathology and various anatomical indices and to assess the diagnostic reproducibility of tomosynthesis for the evaluation of subacromial impingement.

Materials and Methods

A retrospective review of 63 patients with clinically suspected subacromial impingement was conducted. Two musculoskeletal radiologists independently measured the following quantitative data: the AHD on plain radiographs and the AHD at three compartments (anterior, middle, and posterior) using tomosynthesis, computed tomography (CT) arthrography, or magnetic resonance (MR) arthrography. To investigate the association between the AHD and RC pathology and various anatomical indices, we reviewed the arthroscopic operation record as the referenced standard.

Results

The size of rotator cuff tear (RCT) in full-thickness tears displayed a significant inverse correlation with the middle and the posterior tomosynthetic AHDs (p < 0.05). The results of an ANOVA revealed that the middle tomosynthetic AHD retained a significant association with the type of RCT (p = 0.042), and the posterior tomosynthetic AHD retained significance for the size of RCT in a full-thickness tear (p = 0.024). The inter-modality correlation exhibited significant agreement especially among the plain radiography, tomosynthesis, and CT or MR arthrography (p < 0.05). The intraobserver and interobserver correlation coefficients (ICCs) displayed excellent agreement (ICC = 0.896–0.983). The humeral head diameter and glenoid height were significantly correlated with patient height and weight.

Conclusion

Acromiohumeral distance measurement using tomosynthesis is reproducible compared with other modalities.

ACR Appropriateness Criteria® Chronic Extremity Joint Pain-Suspected Inflammatory Arthritis

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. This review first discusses the characteristic osseous and soft tissue abnormalities seen with inflammatory arthritis and how they may be imaged. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity as there is significant overlap of imaging findings among the various types of arthritis. This review provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The value of X-ray digital tomosynthesis in the diagnosis of urinary calculi

Urinary calculus is a common and recurrent condition that affects kidney function. The present study evaluated the use of digital tomosynthesis (DTS) and Kidneys-Ureters-Bladder (KUB) radiography as methods of diagnosing urinary calculi. Unenhanced multidetector computed tomography (UMDCT) was used in the diagnosis of calculi. KUB radiography and DTS procedures were conducted on patients prior to and following bowel preparation to detect kidney, ureteral and bladder calculi. Differences in diagnostic performance of KUB radiography and DTS imaging on prepared and unprepared bowel were evaluated using the χ² test. The consistency of diagnostic results between two examining physicians was analyzed using the κ test. A total of 138 calculi from 80 patients were detected via UMDCT. The calculi detection rates of KUB prior to and following bowel preparation were 47.8 and 66.7% respectively, and the calculi detection rate of DTS prior to and following bowel preparation were 94.2 and 96.4%, respectively. The detection rates of calculi >5 mm via KUB prior to and following bowel preparation were 56.6 and 73.5% respectively, and in DTS they were 100% prior to and following bowel preparation. Economically, DTS performed on the unprepared bowel was the most cost effective, followed by DTS on the prepared bowel, KUB on the unprepared bowel and KUB on the prepared bowel. Therefore, the current study concluded that DTS may be an appropriate first-line imaging technique in patients with urinary calculi.

Interobserver Agreement in Diagnosing Early-Stage Kienböck Disease on Radiographs and Magnetic Resonance Imaging

BACKGROUND

The appearance of early Kienböck disease on radiographs and magnetic resonance imaging (MRI) may be difficult to distinguish from other conditions that affect the lunate. We aimed to assess the interobserver agreement in the diagnosis of early Kienböck disease when evaluated on different imaging modalities.

METHODS

Forty-three hand surgeon members of the Science of Variation Group were randomized to evaluate radiographs and 35 hand surgeons to evaluate radiographs and MRI scans of 26 patients for the presence of Kienböck disease, the lunate type, and the ulnar variance. We used Fleiss' kappa analysis to assess the interobserver agreement for categorical variables and compared the κ values between the 2 groups.

RESULTS

We found that agreement on the diagnosis of early Kienböck disease was fair (κ, 0.36) among observers who evaluated radiographs alone and moderate (κ, 0.58) among observers who evaluated MRI scans in addition to radiographs, and that the difference in κ values was not statistically significant ( P = .057). Agreement did not differ between observers based on imaging modality with regard to the assessment of the lunate type ( P = .75) and ulnar variance ( P = .15).

CONCLUSIONS

We found, with the numbers evaluated, a notable but nonsignificant difference in agreement in favor of observers who evaluated MRI scans in addition to radiographs compared with radiographs alone. Surgeons should be aware that the diagnosis of Kienböck disease in the precollapse stages is not well defined, as evidenced by the substantial interobserver variability.

Adult Inflammatory Arthritides: What the Radiologist Should Know

Developments and improvements in knowledge are rapid and ongoing in both the radiologic and rheumatologic fields. During the past decade, the roles of imaging and the radiologist in the assessment and management of many inflammatory rheumatologic diseases have undergone several changes. To remain effective in patient care, the radiologist needs to be aware of these changes when recommending and interpreting imaging examinations for the referring physician. The goal of contemporary rheumatoid arthritis (RA) management is to redefine RA as a disease that is no longer characterized by erosions, which reflect established or long-standing untreated disease. Most cases of RA are now diagnosed clinically, but imaging increases diagnostic confidence, is superior to clinical examination for the detection of joint inflammation, and plays an important role in patient management. The concept of the seronegative spondyloarthritides has recently been redefined by the Assessment of SpondyloArthritis International Society (ASAS). This new set of ASAS classification criteria divides the spectrum of spondyloarthritis on the basis of predominantly axial skeletal clinical manifestations or predominantly peripheral skeletal clinical manifestations. For axial spondyloarthritis, magnetic resonance imaging and radiography play crucial roles for classification and diagnosis. For both peripheral spondyloarthritis and psoriatic arthritis, the radiologist can provide important information that influences classification and diagnosis, including documenting radiologic evidence of juxta-articular new bone formation, diagnosing sacroiliitis, or delineating the presence and extent of enthesitis and dactylitis. The radiologist's familiarity with recent classification criteria, in addition to the traditional diagnostic characteristics of the individual inflammatory arthritides, maximizes the productive interface between the radiologist and the rheumatologist. ^©RSNA, 2016.

Digital tomosynthesis as a new diagnostic tool for assessing of chronic gout arthritic feet and ankles: comparison of plain radiography and computed tomography

This aimed to compare the three radiographic methods of digital tomosynthesis (DT), plain radiography, and computed tomography (CT) for evaluating changes in feet of patients with chronic gouty arthritis. Two independent radiologists read the plain radiography, DT, and CT images of 30 male patients with gout. The degrees of erosion and joint space narrowing were scored using the Sharp-van der Heijde scoring method in 18 foot joints, which consisted of four proximal interphalangeal and one interphalangeal joint of the first toe, five metatarsophalangeal, five tarsometatarsal, and three naviculo-cuneiform joints of the foot. DT showed high reproducibility [0.929 for intraobserver intraclass correlation coefficient (ICC) and 0.838 for interobserver ICC]. DT showed similar results to those of CT and superior results to those of plain radiography for evaluating radiographic damage [mean total score, 8.5 ± 14.6 (±standard deviation) for plain radiography, 12.9 ± 12.4 for DT, and 12.6 ± 11.2 for CT]. This study showed that DT is a good method for evaluating radiographic changes in patients with gout. Further research is needed to apply DT to actual clinical settings.

Semi-Automated Quantification of Finger Joint Space Narrowing Using Tomosynthesis in Patients with Rheumatoid Arthritis

The purpose of the study is to validate the semi-automated method using tomosynthesis images for the assessment of finger joint space narrowing (JSN) in patients with rheumatoid arthritis (RA), by using the semi-quantitative scoring method as the reference standard. Twenty patients (14 females and 6 males) with RA were included in this retrospective study. All patients underwent radiography and tomosynthesis of the bilateral hand and wrist. Two rheumatologists and a radiologist independently scored JSN with two modalities according to the Sharp/van der Heijde score. Two observers independently measured joint space width on tomosynthesis images using an in-house semi-automated method. More joints with JSN were revealed with tomosynthesis score (243 joints) and the semi-automated method (215 joints) than with radiography (120 joints), and the associations between tomosynthesis scores and radiography scores were demonstrated (P < 0.001). There was significant, negative correlation between measured joint space width and tomosynthesis scores with r = -0.606 (P < 0.001) in metacarpophalangeal joints and r = -0.518 (P < 0.001) in proximal interphalangeal joints. Inter-observer and intra-observer agreement of the semi-automated method using tomosynthesis images was in almost perfect agreement with intra-class correlation coefficient (ICC) values of 0.964 and 0.963, respectively. The semi-automated method using tomosynthesis images provided sensitive, quantitative, and reproducible measurement of finger joint space in patients with RA.

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

Scaphoid fractures constitute 71% of all carpal bone fractures.¹ Early diagnosis and treatment has significant bearing on fracture union rates and better clinical outcomes. While displaced fractures can be readily seen on plain radiograph, undisplaced fractures can require advanced imaging modalities to confirm that diagnosis. Advanced imaging such as Magnetic Resonance Imaging (MRI), Computerised tomography (CT) and bone scintigraphy are routinely used for the diagnosis of scaphoid fractures but require significant radiation exposure, increased cost and can be difficult to access.² Tomosynthesis is an emerging imaging modality which uses conventional x-ray systems to produce cross-sectional images. There has yet to be extensive research carried out investigating the diagnostic value of tomosynthesis in scaphoid fractures. The aim of this study is to optimise patient positioning for the diagnosis of scaphoid fractures in a cadaveric model and compare the diagnostic yield of tomography to conventional CT. Using four cadaveric specimens, three limb positions were examined in unfractured and fractured scaphoids to determine the optimal limb positions required for visualisation of the scaphoid. As a result of this study, the optimal position for visualisation of the scaphoid and diagnosis of scaphoid fractures has been determined. The results demonstrate that tomosynthesis is as effective as CT scanning in identifying scaphoid fractures in both sensitivity and specificity. By comparison to CT, tomosynthesis is cheaper, has lower radiation exposure, requires fewer hospital resources and can be performed quickly. Tomosynthesis is a valid diagnostic tool for the diagnosis of scaphoid fractures.

Peripheral blood T helper type 17 frequency shows an inverse correlation with disease activity and magnetic resonance imaging-based osteitis and erosions in disease-modifying anti-rheumatic drug- and steroid-naive established rheumatoid arthritis

An increased expansion of T helper type 17 (Th17) cells in the synovium has been shown to play a key role in cartilage and bone destruction in rheumatoid arthritis (RA). Because the correlation of the peripheral blood helper T cell subsets and various inflammatory cytokines with the magnetic resonance imaging (MRI)-based parameters have not been studied adequately to date, we sought to look for the same in this study. RA patients with disease duration less than 36 months, disease-modifying anti-rheumatic drugs (DMARDs) and steroid-naive, were recruited. MRI of the dominant hand and wrist was performed using a 0·2 Tesla MRI machine. Peripheral blood Th1 and Th17 were enumerated by flow cytometry and serum interleukin (IL)-6 and IL-17 by enzyme-linked immunosorbent assay (ELISA). Forty consecutive seropositive RA patients [33 females, mean disease duration 12·2 months, mean disease activity score (DAS)28 = 4·4] were included. MRI revealed erosions in 80% of these subjects. On subgroup analysis, prevalence of erosions (94 versus 68%) as well as mean erosion score (11·5 ± 18·9 versus 3·5 ± 6·0) were significantly higher in established RA (13-36 months' duration) compared to early RA (0-12 months). The median peripheral blood Th17 frequencies were significantly higher in patients (1·4%) compared to healthy controls (0·7%) and had a strong negative correlation with MRI parameters of erosion and osteitis as well as with DAS28 in the established RA subgroup. The frequency of peripheral blood Th17 subset was significantly expanded in established RA which correlated inversely with disease activity as well as MRI based erosions and osteitis.

EFFECTIVE DOSE TO PATIENTS FROM THORACIC SPINE EXAMINATIONS WITH TOMOSYNTHESIS

The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph. The total effective doses for the tomosynthesis examinations were obtained by adding the effective doses from the 60 projection radiographs included in the examination. The mean effective dose was 0.47 mSv (range 0.24-0.81 mSv) for the tomosynthesis examinations and 0.20 mSv (range 0.07-0.29 mSv) for the corresponding conventional examinations (anteroposterior + left lateral projection). For the tomosynthesis examinations, a conversion factor between total DAP and effective dose of 0.092 mSv Gycm(-2) was obtained.

Tomosynthesis can facilitate accurate measurement of joint space width under the condition of the oblique incidence of X-rays in patients with rheumatoid arthritis

OBJECTIVE

Accurate evaluation of joint space width (JSW) is important in the assessment of rheumatoid arthritis (RA). In clinical radiography of bilateral hands, the oblique incidence of X-rays is unavoidable, which may cause perceptional or measurement error of JSW. The objective of this study was to examine whether tomosynthesis, a recently developed modality, can facilitate a more accurate evaluation of JSW than radiography under the condition of oblique incidence of X-rays.

METHODS

We investigated quantitative errors derived from the oblique incidence of X-rays by imaging phantoms simulating various finger joint spaces using radiographs and tomosynthesis images. We then compared the qualitative results of the modified total Sharp score of a total of 320 joints from 20 patients with RA between these modalities.

RESULTS

A quantitative error was prominent when the location of the phantom was shifted along the JSW direction. Modified total Sharp scores of tomosynthesis images were significantly higher than those of radiography, that is to say JSW was regarded as narrower in tomosynthesis than in radiography when finger joints were located where the oblique incidence of X-rays is expected in the JSW direction.

CONCLUSION

Tomosynthesis can facilitate accurate evaluation of JSW in finger joints of patients with RA, even with oblique incidence of X-rays.

ADVANCES IN KNOWLEDGE

Accurate evaluation of JSW is necessary for the management of patients with RA. Through phantom and clinical studies, we demonstrate that tomosynthesis may achieve more accurate evaluation of JSW.

Use of Tomosynthesis for Detection of Bone Erosions of the Foot in Patients With Established Rheumatoid Arthritis: Comparison With Radiography and CT

OBJECTIVE

The purpose of this study was to compare tomosynthesis with radiography for the detection of bone erosions of the foot in patients with established rheumatoid arthritis (RA) using MDCT as a reference standard.

SUBJECTS AND METHODS

Eighteen consecutive patients with established RA were included. Each patient underwent radiography, tomosynthesis, and CT examinations of the feet on the same day. Two radiologists independently determined the number of bone erosions and the Sharp-van der Heijde score with each of the three imaging modalities.

RESULTS

On a total of 216 joints from 18 patients, 216 bone erosions were detected on CT, 215 on tomosynthesis, and 181 with radiography. The mean (± SD) Sharp-van der Heijde score was equivalent for tomosynthesis (18.8 ± 16.8) and CT (19.8 ± 18.5) but was statistically lower for radiography (16.4 ± 18.0) (p = 0.030). The respective overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for tomosynthesis were 80%, 75%, 78%, 76%, and 80%, whereas the respective corresponding values for radiography were 66%, 81%, 74%, 77%, and 71%. The radiation burden of tomosynthesis was almost equivalent to that of radiography.

CONCLUSION

Tomosynthesis has a higher sensitivity than radiography to detect bone erosions of the foot in patients with established RA and imparts an almost equivalent radiation burden.

Demystifying the status of fracture healing using tomosynthesis: A case report

Radiography is the most common imaging method for assessing the progress of fracture healing. However, accurate assessment may be confounded by fracture complexity in which a combination of anatomic overlay and hypertrophic callous can be visually misleading. We present just such an instance in which delayed fracture healing was further elucidated using tomosynthesis.

Detection and measurement of rheumatoid bone and joint lesions of fingers by tomosynthesis: a phantom study for reconstruction filter setting optimization

Rheumatoid arthritis (RA) is a systemic disease that is caused by autoimmunity. RA causes synovial proliferation, which may result in bone erosion and joint space narrowing in the affected joint. Tomosynthesis is a promising modality which may detect early bone lesions such as small bone erosion and slight joint space narrowing. Nevertheless, so far, the optimal reconstruction filter for detection of early bone lesions of fingers on tomosynthesis has not yet been known. Our purpose in this study was to determine an optimal reconstruction filter setting by using a bone phantom. We obtained images of a cylindrical phantom with holes simulating bone erosions (diameters of 0.6, 0.8, 1.0, 1.2, and 1.4 mm) and joint spaces by aligning two phantoms (space widths from 0.5 to 5.0 mm with 0.5 mm intervals), examining six reconstruction filters by using tomosynthesis. We carried out an accuracy test of the bone erosion size and joint space width, done by one radiological technologist, and a test to assess the visibility of bone erosion, done by five radiological technologists. No statistically significant difference was observed in the measured bone erosion size and joint space width among all of the reconstruction filters. In the visibility assessment test, reconstruction filters of Thickness+- and Thickness-- were among the best statistically in all characteristics except the signal-to-noise ratio. The Thickness+- and Thickness-- reconstruction filter may be optimal for evaluation of RA bone lesions of small joints in tomosynthesis.