The 'nutcracker' spino-laminar fracture: evaluation as a sentinel lesion of a hyperextension mechanism in cervical spine trauma.

OBJECTIVE: We hypothesised that the orientation of the fracture line in the cervical vertebral arch depends on the traumatic mechanism, specifically focusing on frontal oblique spino-laminar fractures to determine if this pattern can serve as an indicator of a hyperextension mechanism of injury of the cervical spine. MATERIALS AND METHODS: We reviewed the imaging records of 114 adult patients admitted to the emergency department of the Strasbourg University Hospital for severe polytrauma between January 2016 and December 2021 and who presented with a fracture of the posterior vertebral arch of the lower cervical spine on the whole-body CT scan. A radiology resident (R1) and a musculoskeletal radiologist (R2) independently read the CT scans to determine the type of vertebral arch fracture; inter- and intra-observer agreements were calculated using Cohen's Kappa test. Two musculoskeletal radiologists (R2 and R3) then reviewed the CT scans and possible MRIs to identify specific hyperextension injuries of the cervical spine. The association between frontal oblique spino-laminar fracture and hyperextension injuries was assessed using chi2 test. RESULTS: Thirty-five patients had frontal oblique spino-laminar fractures of the cervical spine. These fractures were significantly associated (p = 0.001) with hyperextension injuries of the cervical spine. The inter- and intra-observer agreements for the identification of these spino-laminar fractures were very good (0.86 (0.75-0.96) and 0.90 (0.81-0.99)). CONCLUSION: Frontal oblique spino-laminar fractures are easily recognisable on CT scans and significantly associated with other traumatic injuries known as resulting from hyperextension. Their identification should lead to a search for potential associated unstable vertebral disco-ligamentous injuries with MRI.

Accuracy of Wireless Hand-Held Guided Ultrasound Injections in the Trapeziometacarpal Joint: A Cadaveric Study.

Background Symptomatic trapeziometacarpal osteoarthrosis can be treated with an ultrasound-guided injection in the early stages. This cadaveric study aimed to assess the hypothesis suggesting enhanced accuracy and reliability of hand-held ultrasound (HHUS) injections compared to blind injections into the trapeziometacarpal joint (TMC). Materials and method Our series included 20 fresh cadaveric hands, with a total of 20 TMC randomly assigned to two groups. In group A, 10 TMC received a blinded injection, and in group B, 10 TMC received an ultrasound-guided injection with HHUS. Methylene blue was injected, and anatomical dissection was performed to assess the intra-articular location of the dye. The injection was considered accurate if the intra-articular synovial fluid was stained after opening the articular capsule on the dorsal approach. If there was no injection, it was inaccurate. A statistical analysis was performed, and p <.05 indicated a significant difference. Results Two thumbs were excluded during the study due to an existing trapeziectomy. In group A, 10 blind injections of TMC were performed, with 70% (7/10) of injections graded as accurate. In group B, eight ultrasound-guided injections were performed, with 75% (6/8) achieving accuracy. A Fisher's exact test was performed, and the results indicated no statistically significant difference in injection accuracy between the two groups (P = 1, odds ratio = 0.788). Conclusion Hand-held ultrasound guided TMC injections were not more accurate than blind injections performed by an experienced hand surgeon. Nonetheless, additional studies with a larger sample and comparative studies with conventional cart-based machines are necessary to evaluate the potential of this newly accessible device.

A comparison of smooth and sharp kernel CT reconstructions in the detection of unilateral sacral fractures.

OBJECTIVE: The goal of this study is to determine whether smooth kernel reconstructions are more sensitive than sharp kernel ones for the detection of sacral stress fractures (SF) using MRI as the reference standard. MATERIALS AND METHODS: This retrospective study included 100 subjects in whom CT and MR of the pelvis were performed for a clinical suspicion of SF from January 2014 to May 2020 in our institution. MR was used as the reference standard for the presence of SF. Smooth and sharp kernel CT datasets of the 100 patients were pooled and analyzed randomly. Three readers of various experiences in MSK imaging independently evaluated the axial CT images for the presence of a SF. RESULTS: SF was present on MR in 31 patients (22 women, 9 men; mean age 73.6 ± 19.6) and absent in 69 (48 women, 21 men; mean age 68.8 ± 19.0). Depending on readers, sensitivities ranged from 58 to 77% for the smooth kernel and from 52 to 74% for the sharp kernel reconstructions. For each reader, sensitivities (as well as negative predictive values) of CT were slightly greater on the smooth kernel reconstructions. CONCLUSION: The use of smooth kernel reconstructions improved the sensitivity of CT for the detection of SF compared to the sharp kernel reconstructions usually used and regardless of the experience of the radiologist. Smooth kernel reconstructions should, therefore, be scrutinized in patients with suspicion of SF.

Exercise-related leg muscle signal changes: assessment using diffusion-weighted MRI.

We aimed to detect physiologic changes of leg muscle signal on magnetic resonance (MR) diffusion-weighted imaging (DWI) in asymptomatic subjects after repetitive plantar flexion exercises. In this monocentric prospective study, DWI of both legs were performed at rest and after exercise periods (5 min, Ex5: and 10 min, Ex10) in 20 active healthy subjects (mean age 31 years). The exercise consisted in repetitive plantar flexion of the right foot using elastic band, the patient being sited directly on the MR table. Both visual semiquantitative evaluations and quantitative (apparent diffusion coefficient, ADC; fractional anisotropy, FA) were performed in 5 leg compartments. Visually, signal changes involved mainly the fibular and gastrocnemius muscles and were considered intense after Ex5 in 3 subjects, moderate only after Ex5 in 10, and moderate only after Ex10 in 4. No changes were visible in 3 subjects. Quantitative evaluation confirmed significant signal changes in the fibular (ADC: + 17.4%, p < 0.001; FA: -8.3%, p = 0.030) and gastrocnemius (ADC: + 13.7%, p < 0.001; FA: -11.4%, p < 0.001) muscles between rest and post-exercise MR. Plantar flexion exercises induce changes on DWI, especially in fibular and gastrocnemius muscles, which can be visually and quantitatively detectable in asymptomatic active subjects.Trial registrationEudraCT 2008-A00694-51.

Shortening the Time Interval for the Referral of Patients With Soft Tissue Sarcoma to Expert Centers Using Mobile Health: Retrospective Study.

BACKGROUND: According to guidelines, all patients with sarcoma must be managed from initial diagnosis at expert sarcoma centers. However, in everyday practice, the time interval to an expert center visit can be long, which delays presentation to an expert multidisciplinary tumor board and increases the risk of inappropriate management, negatively affecting local tumor control and prognosis. The advent of mobile health offers an easy way to facilitate communication and cooperation between general health care providers (eg, general practitioners and radiologists) and sarcomas experts. We developed a mobile app (Sar'Connect) based on the algorithm designed by radiologists from the French Sarcoma Group. Through a small number of easy-to-answer questions, Sar'Connect provides personalized advice for the management of patients and contact information for the closest expert center. OBJECTIVE: This retrospective study is the first to assess this mobile app's potential benefits in reducing the time interval for patient referral to an expert center according to the initial clinical characteristics of the soft tissue tumor. METHODS: From May to December 2021, we extracted tumor mass data for 78 patients discussed by the multidisciplinary tumor boards at 3 centers of the French Sarcoma Group. We applied the Sar'Connect algorithm to these data and estimated the time interval between the first medical description of the soft tissue mass and the referral to expert center. We then compared this estimated time interval with the observed time interval. RESULTS: We found that the use of Sar'Connect could potentially shorten the time interval to an expert center by approximately 7.5 months (P<.001). Moreover, for half (31/60, 52%) of the patients with a malignant soft tissue tumor, Sar'Connect could have avoided inappropriate management outside of the reference center. We did not identify a significant determinant for shortening the time interval for referral. CONCLUSIONS: Overall, promoting the use of a simple mobile app is an innovative and straightforward means to potentially accelerate both the referral and management of patients with soft tissue sarcoma at expert centers.

The concept of ring of injuries: evaluation in ankle trauma.

OBJECTIVE: Radiographs are first-line imaging in ankle trauma but lack sensitivity to detect ligamentous injuries and undisplaced fractures. Our hypothesis was that ankle injuries occur in predefined sequences along two osteoligamentous rings, so that occult injuries non-visible on initial radiographs can be predicted. We, therefore, aimed to validate a ring model of progressive damages in the interpretation of ankle trauma radiographs. METHODS: This study retrospectively enrolled 277 adult patients that presented an acute fibular fracture on ankle radiographs between May and November 2019. Four different types of fibula fracture were differentiated, each being considered to correspond to a different mechanism of injury. Patients were classified into four groups, upon the appearance of their fibular fracture. Then, injuries to the distal tibiofibular syndesmosis, medial malleolus, and deltoid ligament (medial clear space) were assessed in each patient radiographs. Traumatic injuries were independently evaluated by a resident and an experienced MSK radiologist. For each patient, observed features were compared to those predicted by the ring concept. Inter- and intraobserver agreements were calculated. RESULTS: Injuries were observed according to the predictable sequence in 266 of the 277 patients (96%). In the 11 remaining patients, discordances were presumably due to undisplaced injuries to the syndesmosis or deltoid ligament. Agreements were considered very good for each evaluated item. CONCLUSION: The Lauge-Hansen ring concept was found to be highly accurate and reproducible for radiographic assessment of ankle injuries. Discordances to the predicted sequence might reflect occult injuries, especially of the syndesmosis or deltoid ligament.

Evaluation of neuroradiology emergency MRI interpretations: low discrepancy rates between on-call radiology residents' preliminary interpretations and neuroradiologists' final reports.

OBJECTIVES: To evaluate the performance of on-call radiology residents in interpreting alone brain and spine MRI studies performed after hours, to describe their mistakes, and to identify influencing factors that increased the occurrence of errors. METHODS: A total of 328 MRI examinations performed during a 13-month period (from December 1, 2019, to January 1, 2021) were prospectively included. Discrepancies between the preliminary interpretation of on-call radiology residents and the final reports of attending neuroradiologists were noted and classified according to a three-level score: level 1 (perfect interpretation or minor correction), level 2 (important correction without immediate change in patient management), or level 3 (major correction with immediate change in patient management). Categorical data were compared using Fisher's exact test. RESULTS: The overall discrepancy rate (level-2 and level-3 errors) was 16%; the rate of major discrepancies (only level-3 errors) was 5.5%. The major-discrepancy rate of second-year residents, when compared with that of senior residents, was significantly higher (p = 0.02). Almost all of the level-3 errors concerned cerebrovascular pathology. The most common level-2 errors involved undescribed aneurysms. We found no significant difference in the major-discrepancy rate regarding time since the beginning of the shift. CONCLUSIONS: The great majority of examinations were correctly interpreted. The rate of major discrepancies in our study was comparable to the data in the literature, and there was no adverse clinical outcome. The level of residency has an effect on the rate of serious errors in residents' reports. KEY POINTS: • The rate of major discrepancies between preliminary MRI interpretations by on-call radiology residents and final reports by attending neuroradiologists is low, and comparable to discrepancy rates reported for head CT interpretations. • The youngest residents made significantly more serious errors when compared to senior residents. • There was no adverse clinical outcome in patient morbidity as a result of an initial misdiagnosis.

Together Intra-Tumor Hypoxia and Macrophagic Immunity Are Driven Worst Outcome in Pediatric High-Grade Osteosarcomas.

BACKGROUND: Osteosarcomas (OTS) represent the most common primary bone cancer diagnosed in adolescents and young adults. Despite remarkable advances, there are no objective molecular or imaging markers able to predict an OTS outcome at diagnosis. Focusing on biomarkers contributing broadly to treatment resistance, we examine the interplay between the tumor-associated macrophages and intra-tumor hypoxia. METHODS: Radiological and immunohistochemical (IHC) data were correlated with the outcome in a retrospective and monocentric cohort of 30 pediatric OTS. We studied hypoxic (pS6, phospho-mTor, HIF-1α and carbonic anhydrase IX (CAIX)) and macrophagic (CD68 and CD163) biomarkers. RESULTS: The imaging analyses were based on MRI manual volumetric measures on axial post-contrast T1 weighted images, where, for each tumor, we determined the necrotic volume and its ratio to the entire tumor volume. When they were above 50 cm3 and 20%, respectively, they correlated with a worse overall survival (p = 0.0072 and p = 0.0136, respectively) and event-free survival (p = 0.0059 and p = 0.0143, respectively). IHC assessments enable a significant statistical link between HIF-1α/CAIX hyper-expressions, CD68+ cells and a worse outcome, whereas activation of mTor pathway was linked to a better survival rate and CD163+ cells. CONCLUSIONS: This study evidenced the links between hypoxia and immunity in OTS, as their poor outcome may be related to a larger necrotic volume on diagnostic MRI and, in biopsies, to a specific IHC profile.

Presurgical Perspective and Postsurgical Evaluation of Calcaneal and Talus Fractures.

Fractures of the calcaneus and talus are severe injuries that usually result from high-energy trauma. The calcaneus and talus are essential for the transmission of body weight, so an optimal reduction and/or fixation of fractures is required to prevent disabling consequences. These fractures almost always have an articular involvement, and an anatomical reduction is required; any residual step-off would lead to joint incongruity and secondary arthrosis.The aims of imaging are first, to guide management by describing the fracture characteristics (e.g., location, displacement, fragments, articular involvement, soft tissue compromise), and second, to detect early and late surgical complications (e.g., infection, malunion, nonunion, arthrosis, hardware issues). Although radiographs remain the first-line imaging modality for the screening of ankle and foot trauma, computed tomography is almost always required for the initial management and follow-up of the patient.

Thermal bone injuries: postmortem computed tomography findings in 25 cases.

INTRODUCTION: Fire death investigations attempt to determine whether a subject was alive or dead before the fire started. Therefore, it is essential to assess if the bone damage is traumatic or the result of exposure to heat. This observational study aims to expose the specific CT semiology of thermal bone lesions to allow the forensic radiologist to identify and distinguish them from traumatic lesions that would have preceded death. MATERIALS AND METHODS: We retrospectively reviewed the CT findings of 25 bodies with thermal bone lesions for which a postmortem computed tomography (PMCT) was performed prior to an autopsy. Imaging findings were correlated to the autopsy data to identify the specific features of thermal bone lesions. RESULTS: Specific signs of thermal injuries to bone were identified on PMCT on all deceased cases. Thermal damages predominated in areas directly exposed to flames (rib cage, distal extremities) with less soft tissue coverage ("soft tissue shielding"). The mottled appearance of bone marrow was a constant sign of burned bones. Heat fractures such as trans-diploic fractures of flat bones and beveled ("flute-mouthpiece") fractures of extremities seemed specifically related to thermal mechanism. In addition, we provided a better description of superficial cortical fissures of flat bones ("ancient Chinese porcelain") and observed a "stair step" fracture of a long bone until now undescribed in radiological literature. CONCLUSION: Thermal bone lesions have specific CT findings, different on several points from traumatic injuries. Their knowledge is essential for radiologists and forensic physicians to provide an accurate report of injury and conclusions.

Biceps, Brachialis, and Triceps.

Tendon injuries at the elbow affect mostly the distal biceps and can progressively degenerate over time or rupture in an acute event. The degree of retraction may depend on the integrity of the lacertus fibrosus, a fibrous expansion that merges with the forearm flexor fascia. Biceps disorders are frequently associated with fluid or synovitis of the adjacent bicipital bursa; primary bursal disorders (primary inflammatory synovitis) can also be observed. Distal triceps is less frequently injured than the distal biceps, and tears usually manifest as distal ruptures with avulsion of a small flake of bone from the tip of the olecranon. Brachialis injuries are uncommon and the consequence of sudden muscle stretching during forced elbow hyperextension, as in posterior elbow luxation.

Spontaneous infarction of lumbar roots, vertebrae and paravertebral muscles.

Ischemic injury to the lumbosacral nerve roots and plexus is a rare condition resulting from thrombosis of one or several lumbar arteries. As the arterial supply of the spine presents great variations between subjects, the clinical presentation of lumbar thrombosis is highly variable depending on the relative involvement of nerve roots, bones or muscles. Diagnosis can be challenging, especially in the acute phase, as different structures can be simultaneously involved. The identification of an enlarged vessel centered in the area of tissue damage can help with the final diagnosis. We present the case of a 59-year-old woman who presented with spontaneous incomplete cauda equina syndrome due to diffuse lumbar nerve root infarction. On imaging, acute lumbar artery thrombosis was confirmed, and in addition to nerve roots, adjacent vertebral and paraspinal muscle infarctions were also present.

Critical illness-associated cerebral microbleeds for patients with severe COVID-19: etiologic hypotheses.

BACKGROUND AND PURPOSE: During the COVID-19 outbreak, the presence of extensive white matter microhemorrhages was detected by brain MRIs. The goal of this study was to investigate the origin of this atypical hemorrhagic complication. METHODS: Between March 17 and May 18, 2020, 80 patients with severe COVID-19 infections were admitted for acute respiratory distress syndrome to intensive care units at the University Hospitals of Strasbourg for whom a brain MRI for neurologic manifestations was performed. 19 patients (24%) with diffuse microhemorrhages were compared to 18 control patients with COVID-19 and normal brain MRI. RESULTS: The first hypothesis was hypoxemia. The latter seemed very likely since respiratory failure was longer and more pronounced in patients with microhemorrhages (prolonged endotracheal intubation (p = 0.0002), higher FiO2 (p = 0.03), increased use of extracorporeal membrane oxygenation (p = 0.04)). A relevant hypothesis, the role of microangiopathy, was also considered, since patients with microhemorrhages presented a higher increase of the D-Dimers (p = 0.01) and a tendency to more frequent thrombotic events (p = 0.12). Another hypothesis tested was the role of kidney failure, which was more severe in the group with diffuse microhemorrhages (higher creatinine level [median of 293 µmol/L versus 112 µmol/L, p = 0.04] and more dialysis were introduced in this group during ICU stay [12 versus 5 patients, p = 0.04]). CONCLUSIONS: Blood-brain barrier dysfunction secondary to hypoxemia and high concentration of uremic toxins seems to be the main mechanism leading to critical illness-associated cerebral microbleeds, and this complication remains to be frequently described in severe COVID-19 patients.

Cerebrospinal Fluid Features in Patients With Coronavirus Disease 2019 and Neurological Manifestations: Correlation with Brain Magnetic Resonance Imaging Findings in 58 Patients.

BACKGROUND: Neurological manifestations are common in patients with coronavirus disease 2019 (COVID-19), but little is known about pathophysiological mechanisms. In this single-center study, we examined neurological manifestations in 58 patients, including cerebrospinal fluid (CSF) analysis and neuroimaging findings. METHODS: The study included 58 patients with COVID-19 and neurological manifestations in whom severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction screening and on CSF analysis were performed. Clinical, laboratory, and brain magnetic resonance (MR) imaging data were retrospectively collected and analyzed. RESULTS: Patients were mostly men (66%), with a median age of 62 years. Encephalopathy was frequent (81%), followed by pyramidal dysfunction (16%), seizures (10%), and headaches (5%). CSF protein and albumin levels were increased in 38% and 23%, respectively. A total of 40% of patients displayed an elevated albumin quotient, suggesting impaired blood-brain barrier integrity. CSF-specific immunoglobulin G oligoclonal band was found in 5 patients (11%), suggesting an intrathecal synthesis of immunoglobulin G, and 26 patients (55%) presented identical oligoclonal bands in serum and CSF. Four patients (7%) had a positive CSF SARS-CoV-2 reverse-transcription polymerase chain reaction. Leptomeningeal enhancement was present on brain MR images in 20 patients (38%). CONCLUSIONS: Brain MR imaging abnormalities, especially leptomeningeal enhancement, and increased inflammatory markers in CSF are frequent in patients with neurological manifestations related to COVID-19, whereas SARS-CoV-2 detection in CSF remained scanty.

Cerebral vasculitis of medium-sized vessels as a possible mechanism of brain damage in COVID-19 patients.

BACKGROUND AND PURPOSE: Cerebral complications related to COVID-19 were recently reported, and the underlying mechanisms of brain damage remain uncertain, probably multifactorial. Among various hypotheses suggested, a possible vasculitis was issued but never confirmed. Herein, we aimed to describe brain MRIs focused on the intracranial vessel wall in a population of COVID-19 patients with neurologic manifestations. MATERIALS AND METHODS: Between March 1 and May 31, 2020, 69 consecutive COVID-19 patients with neurologic manifestations underwent a brain MRI allowing the study of the intracranial vessel wall at Strasbourg University hospitals and were retrospectively included. During the same period, 25 consecutive patients, without suspicion of SARS-CoV-2 infection, underwent a brain MRI urgently, with the same imaging protocols. A vasculitis seemed likely when imaging demonstrated vessel wall thickening with homogeneous and concentric enhancement. RESULTS: Among the 69 COVID-19 patients included, 11 (16%) presented arterial vessel wall thickening with homogeneous and concentric enhancement, compatible with cerebral vasculitis. These neuroimaging findings were not found among the 25 patients without SARS-CoV-2 infection, and the difference was statistically significant (p = 0.03). Middle cerebral arteries, basilar artery, and posterior cerebral arteries were the most frequent vessels involved. For nine of them, imaging demonstrated ischemic or hemorrhagic complications. CONCLUSION: Cerebral vasculitis of medium-sized vessels seems to be one of the mechanisms at the origin of brain damage related to COVID-19.

Signal changes in enhanced T1-weighted images related to gadolinium retention: A three-time-point imaging study.

BACKGROUND AND PURPOSE: Concern has grown about the finding of gadolinium deposits in the brain after administering gadolinium-based contrast agents (GBCAs). The mechanism is unclear, and related questions remain unanswered, including the stability over time. Therefore, we conducted a three-time-point study to explore T1-weighted (W) signal changes in the dentate nucleus (DN) and globus pallidus (GP), after the first, fifth, and tenth injections of either a macrocyclic agent (gadoterate meglumine) or a linear agent (gadobenate dimeglumine). MATERIALS AND METHODS: For this retrospective, multicenter, longitudinal study, two groups of 18 (gadoterate meglumine) and 19 (gadobenate dimeglumine) patients were identified. The evolution of the signal over time was analyzed using DN/pons (DN/P) and GP/thalamus (GP/T) ratios. RESULTS: DN/P and GP/T ratios tended to increase after the fifth administration of gadobenate dimeglumine, following by a downward trend. A trend in a decrease in DN/P and GP/T ratios were found after the fifth and tenth administrations of gadoterate meglumine. CONCLUSION: After exposure to gadobenate dimeglumine, the signal intensity (SI) tended to increase after the fifth injection owing to gadolinium accumulation, however, a SI increase was not found after the tenth administration supporting the hypothesis of a slow elimination of the previously retained gadolinium (wash-out effect) from the brain or of a change in form (by dechelation), causing the signal to fade. No increasing SI was found in the DN and GP after exclusive exposure to gadoterate meglumine, thus confirming its stability. We found, instead, a trend for a significative gadolinium elimination over time.

A French case of porocephalosis diagnosed by radiologists.

Porocephalosis is the name given to human infection by Armillifer, which is rare, especially in European and North American populations. Among the few cases reported to date, most of them were described in the African community. Humans can become infected, for example, consuming undercooked meat from infected snakes. Herein we report the case of a 31-year-old male, originally from the Democratic Republic of the Congo, who was living in France for many years and presented with lower back pain and mild abdominal pain. Imaging showed multiple comma-shaped calcifications disseminated in the liver and the peritoneal cavity, without any additional feature. The patient reported regular consumption of snake meat during his travels in Africa, and thus the diagnosis of porocephalosis could be made. Doctors treating patients from endemic areas or traveling in endemic areas, particularly in Africa, should become familiar with this infection and consider it in the case of multiple calcifications on imaging. More cases of porocephalosis are likely to be seen in the future because of the increase in international travel.