A comparative study of image quality and diagnostic confidence in diagnosis and follow-up of scaphoid fractures using photon-counting detector CT and energy-integrating detector CT.

PURPOSE: Scaphoid fractures in patients and assessment of healing using PCD-CT have, as far as we know, not yet been studied. Therefore, the aim was to compare photon counting detector CT (PCD-CT) with energy integrating detector CT (EID-CT) in terms of fracture visibility and evaluation of fracture healing. METHOD: Eight patients with scaphoid fracture were examined with EID-CT and PCD-CT within the first week post-trauma, and with additional scans at 4, 6 and 8 weeks. Our clinical protocol for wrist examination with EID-CT was used (CTDIvol 3.1 ± 0.1 mGy, UHR kernel Ur77). For PCD-CT matched radiation dose, reconstruction kernel Br89. Quantitative analyses of noise, CNR, trabecular and cortical sharpness, and bone volume fraction were conducted. Five radiologists evaluated the images for fracture visibility, fracture gap consolidation and image quality, and rated their confidence in the diagnosis. RESULTS: The trabecular and cortical sharpness were superior in images obtained with PCD-CT compared with EID-CT. A successive reduction in trabecular bone volume fraction during the immobilized periods was found with both systems. Despite higher noise and lower CNR with PCD-CT, radiologists rated the image quality of PCD-CT as superior. The visibility of the fracture line within 1-week post-trauma was rated higher with PCD-CT as was diagnostic confidence, but the subsequent assessments of fracture gap consolidation during healing process and the confidence in diagnosis were found equivalent between both systems. CONCLUSION: PCD-CT offers superior visibility of bone microstructure compared with EID-CT. The evaluation of fracture healing and confidence in diagnosis were rated equally with both systems, but the radiologists found primary fracture visibility and overall image quality superior with PCD-CT.

A prophylactic subcutaneous dose of the anticoagulant tinzaparin does not influence qPCR-based assessment of circulating levels of miRNA in humans.

Circulating microRNAs (miRNAs) have become increasingly popular biomarker candidates in various diseases. However, heparin-based anticoagulants might affect the detection of target miRNAs in blood samples during quantitative polymerase chain reaction (qPCR)-based analysis of miRNAs involving RNA extraction, cDNA synthesis and the polymerase catalyzed reaction. Because low-molecular-weight heparins (LMWH) are widely used in routine healthcare, we aimed to investigate whether a prophylactic dose of the LMWH tinzaparin influences qPCR-based quantification of circulating miRNAs. A total of 30 subjects were included: 16 fracture patients with tinzaparin treatment and 14 non-fracture controls without anticoagulation therapy. To control for the effect of tinzaparin on miRNA analysis an identical concentration of synthetic miRNAs was added to plasma, isolated RNA and prepared complementary DNA (cDNA) from all samples in both groups. No significant difference was observed for cDNA synthesis or qPCR when comparing tinzaparin-treated patients with untreated controls. Among the tinzaparin-treated patients, plasma levels of six endogenous miRNAs (hsa-let-7i-5p, hsa-miR-30e-5p, hsa-miR-222-3p, hsa-miR-1-3p, hsa-miR-133a-3p, hsa-miR-133b) were measured before and one to six hours after a subcutaneous injection of tinzaparin 4500IU. No significant effect was observed for any of the investigated miRNAs. A prophylactic dose of 4500IU tinzaparin does not seem to affect cDNA synthesis or qRT-PCR-based quantification of circulating miRNAs.

The Choice of Osteosynthesis for Distal Radius Fractures: A Matter of Taste, Fracture Instability, or Patient-Related Factors? A Retrospective Study of Functional Outcome in 346 Distal Radius Fractures Operated With Percutaneous Wires or Volar Plate Fixation.

BACKGROUND: Surgery with volar locking plate (VLP) for distal radius fractures (DRFs) has become dominant over percutaneous Kirschner wire (K-wire) (PKW) fixation. Not many studies have proved advantages of the VLP and the increasing dominance of the VLP is thus not derived from evidence of superiority but influenced by other factors. METHODS: By retrospectively classifying 346 DRFs treated with either PKW or VLP fixation, according to the Buttazzoni classification system, we aimed to investigate the determining factors for choice of surgical method, and by review of the patients' medical records, the functional outcome, duration, and frequentness of the rehabilitation period were correlated to Buttazzoni type and surgical method. RESULTS: The odds ratio of having volar plate fixation was negatively correlated to age and positively correlated to a higher Buttazzoni type. We found no clinically significant differences in the functional outcome for different Buttazzoni type of fractures within the VLP and PKW groups, respectively, nor between the 2 methods of surgery for any Buttazzoni type of fracture. CONCLUSION: Younger patients and fractures with higher grade of instability were more likely to be treated with VLP than PKW; however, neither fracture instability nor surgical method had any impact on functional outcome.

Reliability and Validity of an Ultrasound-Based Protocol for Measurement of Quadriceps Muscle Thickness in Children.

Introduction and aims: Accurate determination of skeletal muscle size is of great importance in multiple settings including resistance exercise, aging, disease, and disuse. Ultrasound (US) measurement of muscle thickness (MT) is a method of relatively high availability and low cost. The present study aims to evaluate a multisite ultrasonographic protocol for measurement of MT with respect to reproducibility and correlation to gold-standard measurements of muscle volume (MV) with magnetic resonance imaging (MRI) in children. Material and methods: 15 children completed the study (11 ± 1 year, 41 ± 8 kg, 137 ± 35 cm). Following 20 min supine rest, two investigators performed US MT measurements of all four heads of the m. quadriceps femoris, at pre-determined sites. Subsequently, MRI scanning was performed and MV was estimated by manual contouring of individual muscle heads. Results: Ultrasound measurement of MT had an intra-rater reliability of ICC = 0.985-0.998 (CI 95% = 0.972-0.998) and inter-rater reliability of ICC = 0.868-0.964 (CI 95% = 0.637-0.983). The US examinations took less than 15 min, per investigator. Muscle thickness of all individual quadriceps muscles correlated significantly with their corresponding MV as measured by MRI (overall r = 0.789, p < 0.001). Conclusion: The results of this study indicate that US measurement of MT using a multisite protocol is a competitive alternative to MRI scanning, especially with respect to availability and time consumption. Therefore, US MT could allow for wider clinical and scientific implementation.

BioFACTS: biomarkers of rhabdomyolysis in the diagnosis of acute compartment syndrome - protocol for a prospective multinational, multicentre study involving patients with tibial fractures.

INTRODUCTION: The ischaemic pain of acute compartment syndrome (ACS) can be difficult to discriminate from the pain linked to an associated fracture. Lacking objective measures, the decision to perform fasciotomy is based on clinical findings and performed at a low level of suspicion. Biomarkers of muscle cell damage may help to identify and monitor patients at risk, similar to current routines for patients with acute myocardial infarction. This study will test the hypothesis that biomarkers of muscle cell damage can predict ACS in patients with tibial fractures. METHODS AND ANALYSIS: Patients aged 15-65 years who have suffered a tibial fracture will be included. Plasma (P)-myoglobin and P-creatine phosphokinase will be analysed at 6-hourly intervals after admission to the hospital (for 48 hours) and-if applicable-after surgical fixation or fasciotomy (for 24 hours). In addition, if ACS is suspected at any other point in time, blood samples will be collected at 6-hourly intervals. An independent expert panel will assess the study data and will classify those patients who had undergone fasciotomy into those with ACS and those without ACS. All primary comparisons will be performed between fracture patients with and without ACS. The area under the receiver operator characteristics curves will be used to identify the success of the biomarkers in discriminating between fracture patients who develop ACS and those who do not. Logistic regression analyses will be used to assess the discriminative abilities of the biomarkers to predict ACS corrected for prespecified covariates. ETHICS AND DISSEMINATION: The study has been approved by the Regional Ethical Review Boards in Linköping (2017/514-31) and Helsinki/Uusimaa (HUS/2500/2000). The BioFACTS study will be reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology recommendations. TRIAL REGISTRATION NUMBER: NCT04674592.

Cone-beam computed tomography for primary investigation of wrist trauma provides a new map of fractures of carpal bones.

In 2016, our primary modality for radiological examination of wrist trauma, was changed from radiography to cone-beam computed tomography (CBCT). This is a retrospective survey of carpal bone fractures detected by CBCT during 6 months in 2016/2017, compared with those found on conventional radiographs during 6 months in 2013/2014. The incidence of carpal fractures was three times higher during the CBCT period (92/100,000 per year) compared with the radiography period (29/100,000 per year) and the spectrum of anatomical locations was different between the two periods, with fractures of the lunate (n = 6), trapezium (n = 9), trapezoid (n = 4) and capitate (n = 1) detected by CBCT, in contrast to no fractures of these bones diagnosed during the 6 months radiography period. We suggest a more liberal use of CBCT for examination of wrist trauma considering the benefits of being able to give patients a correct primary diagnosis, treatment and prognosis.Level of evidence: III.

Cortical plasticity in patients with median nerve lesions studied with MEG.

We have previously shown age- and time-dependent effects on brain activity in the primary somatosensory cortex (SI), in a functional magnetic resonance imaging (fMRI) study of patients with median nerve injury. Whereas fMRI measures the hemodynamic changes in response to increased neural activity, magnetoencephalography (MEG) offers a more concise way of examining the evoked response, with superior temporal resolution. We therefore wanted to combine these imaging techniques to gain additional knowledge of the plasticity processes in response to median nerve injury. Nine patients with median nerve trauma at the wrist were examined with MEG. The N1 and P1 responses at stimulation of the injured median nerve at the wrist were lower in amplitude compared to the healthy side (p < .04). Ulnar nerve stimulation of the injured hand resulted in larger N1 amplitude (p < .04). The amplitude and latency of the response did not correlate with the sensory discrimination ability. There was no correlation between N1 amplitude and size of cortical activation in fMRI. There was no significant difference in N1 latency between the injured and healthy median nerve. N1 latency correlated positively with age in both the median and ulnar nerve, and in both the injured and the healthy hand (p < .02 or p < .001). It is concluded that conduction failure in the injured segment of the median nerve decreases the amplitude of the MEG response. Disinhibition of neighboring cortical areas may explain the increased MEG response amplitude to ulnar nerve stimulation. This can be interpreted as a sign of brain plasticity.

Inter-hemispheric plasticity in patients with median nerve injury.

Peripheral nerve injuries result in reorganization within the contralateral hemisphere. Furthermore, recent animal and human studies have suggested that the plastic changes in response to peripheral nerve injury also include several areas of the ipsilateral hemisphere. The objective of this study was to map the inter-hemispheric plasticity in response to median nerve injury, to investigate normal differences in contra- and ipsilateral activation, and to study the impact of event-related or blocked functional magnetic resonance imaging (fMRI) design on ipsilateral activation. Four patients with median nerve injury at the wrist (injured and epineurally sutured >2 years earlier) and ten healthy volunteers were included. 3T fMRI was used to map the hemodynamic response to brain activity during tactile stimulation of the fingers, and a laterality index (LI) was calculated. Stimulation of Digits II-III of the injured hand resulted in a reduction in contralateral activation in the somatosensory area SI. Patients had a lower LI (0.21±0.15) compared to healthy controls (0.60±0.26) indicating greater ipsilateral activation of the primary somatosensory cortex. The spatial dispersion of the coordinates for areas SI and SII was larger in the ipsilateral than in the contralateral hemisphere in the healthy controls, and was increased in the contralateral hemisphere of the patients compared to the healthy controls. There was no difference in LI between the event-related and blocked paradigms. In conclusion, patients with median nerve injury have increased ipsilateral SI area activation, and spatially more dispersed contralateral SI activation during tactile stimulation of their injured hand. In normal subjects ipsilateral activation has larger spatial distribution than the contralateral. Previous findings in patients performed with the blocked fMRI paradigm were confirmed. The increase in ipsilateral SI activation may be due to an interhemispheric disinhibition associated with changes in the afferent signal inflow to the contralateral primary somatosensory cortex.

Age- and time-dependent effects on functional outcome and cortical activation pattern in patients with median nerve injury: a functional magnetic resonance imaging study.

OBJECT: The authors conducted a study to determine age- and time-dependent effects on the functional outcome after median nerve injury and repair and how such effects are related to changes in the pattern of cortical activation in response to tactile stimulation of the injured hand. METHODS: The authors studied 11 patients with complete unilateral median nerve injury at the wrist repaired with epineural suture. In addition, 8 patients who were reported on in a previous study were included in the statistical analysis. In the entire study cohort, the mean age at injury was 23.3 +/- 13.4 years (range 7-57 years) and the time after injury ranged from 1 to 11 years. Sensory perception was measured with the static 2-point discrimination test and monofilaments. Functional MR imaging was conducted during tactile stimulation (brush strokes) of Digits II-III and IV-V of both hands, respectively. RESULTS: Tactile sensation was diminished in the median territory in all patients. The strongest predictor of 2-point discrimination was age at injury (p < 0.0048), and when this was accounted for in the regression analysis, the other age- and time-dependent predictors had no effect. The activation ratios (injured/healthy hand) for Digit II-III and Digit IV-V stimulation were positively correlated (rho 0.59, p < 0.011). The activation ratio for Digit II-III stimulation correlated weakly with time after injury (p < 0.041). The activation ratio of Digits IV-V correlated weakly with both age at injury (p < 0.048) and time after injury (p < 0.033), but no predictor reached significance in the regression model. The mean ratio of ipsi- and contralateral hemisphere activation after stimulation of the injured hand was 0.55, which was not significantly different from the corresponding ratio of the healthy hand (0.66). CONCLUSIONS: Following a median nerve injury (1-11 years after injury) there may be an initial increase in the volume of the cortical representation, which subsequently declines during the restoration phase. These dynamic changes may involve both median and ulnar nerve cortical representation, because both showed negative correlation with time after injury. These findings are in agreement with animal studies showing that cortical plasticity is an important mechanism for functional recovery after peripheral nerve injury and repair.