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Objective: Magnetic resonance guided transcranial focused ultrasound holds great promises for treating neurological disorders. This technique relies on skull aberration correction which requires computed tomography (CT) scans of the skull of the patients. Recently, ultra-short time-echo (UTE) magnetic resonance (MR) sequences have unleashed the MRI potential to reveal internal bone structures. In this study, we measure the efficacy of transcranial aberration correction using UTE images.
Approach. We compare the efficacy of transcranial aberration correction using UTE scans to CT based correction on four skulls and two targets using a clinical device (Exablate Neuro, Insightec, Israel). We also evaluate the performance of a custom ray tracing algorithm using both UTE and CT estimates of acoustic properties and compare these against the performance of the manufacturer's proprietary aberration correction software. 
Main results. UTE estimated skull maps in Hounsfield units (HU) had a mean absolute error of 242 ± 20 HU (n=4). The UTE skull maps were sufficiently accurate to improve pressure at the target (no correction: 0.44 ± 0.10, UTE correction: 0.79 ± 0.05, manufacturer CT: 0.80 ± 0.05), pressure confinement ratios (no correction: 0.45 ± 0.10, UTE correction: 0.80 ± 0.05, manufacturer CT: 0.81 ± 0.05), and targeting error (no correction: 1.06 ± 0.42 mm, UTE correction 0.30 ± 0.23 mm, manufacturer CT: 0.32 ± 0.22) (n=8 for all values). When using CT, our ray tracing algorithm performed slightly better than UTE based correction with pressure at the target (UTE: 0.79 ± 0.05, CT: 0.84 ± 0.04), pressure confinement ratios (UTE: 0.80 ± 0.05, CT: 0.84 ± 0.04), and targeting error (UTE: 0.30 ± 0.23 mm, CT: 0.17 ± 0.15). 
Significance. These 3D transcranial measurements suggest that UTE sequences could replace CT scans in the case of MR guided focused ultrasound with minimal reduction in performance which will avoid ionizing radiation exposure to the patients and reduce procedure time and cost.&#xD., (© 2024 Institute of Physics and Engineering in Medicine.)

Background: Transcranial ultrasound stimulation (TUS) is a non-invasive brain stimulation technique; when skull aberrations are compensated for, this technique allows, with millimetric accuracy, circumvention of the invasive surgical procedure associated with deep brain stimulation (DBS) and the limited spatial specificity of transcranial magnetic stimulation., Objective: /hypothesis: We hypothesize that MR-guided low-power TUS can induce a sustained decrease of tremor power in patients suffering from medically refractive essential tremor., Methods: The dominant hand only was targeted, and two anatomical sites were sonicated in this exploratory study: the ventral intermediate nucleus of the thalamus (VIM) and the dentato-rubro-thalamic tract (DRT). Patients (N = 9) were equipped with MR-compatible accelerometers attached to their hands to monitor their tremor in real-time during TUS., Results: VIM neurostimulations followed by a low-duty cycle (5 %) DRT stimulation induced a substantial decrease in the tremor power in four patients, with a minimum of 89.9 % reduction when compared with the baseline power a few minutes after the DRT stimulation. The only patient stimulated in the VIM only and with a low duty cycle (5 %) also experienced a sustained reduction of the tremor (up to 93.4 %). Four patients (N = 4) did not respond. The temperature at target was 37.2 ± 1.4 °C compared to 36.8 ± 1.4 °C for a 3 cm away control point., Conclusions: MR-guided low power TUS can induce a substantial and sustained decrease of tremor power. Follow-up studies need to be conducted to reproduce the effect and better to understand the variability of the response amongst patients. MR thermometry during neurostimulations showed no significant thermal rise, supporting a mechanical effect., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: IR and YS are employees of Insightec. JFA received a research grant from Insightec for preclinical work on transcranial ultrasound., (Copyright © 2024. Published by Elsevier Inc.)

Purpose of Review: The rising prevalence of neurodegenerative and mental disorders, combined with the challenges posed by their frailty, has presented intensivists with complex issues in the intensive care unit (ICU). This review article explores specific aspects of care for patients with catatonia, Parkinson's disease (PD), and dementia within the context of the ICU, shedding light on recent developments in these fields., Recent Findings: Catatonia, a neuropsychiatric syndrome with potentially life-threatening forms, remains underdiagnosed, and its etiologies are diverse. PD patients in the ICU present unique challenges related to admission criteria, dopaminergic treatment, and respiratory care. Dementia increases the risk of delirium. Delirium is associated with long-term cognitive impairment and dementia., Summary: While evidence is lacking, further research is needed to guide treatment for ICU patients with these comorbidities., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Catatonia is a psychomotor syndrome frequently observed in disorders with neurodevelopmental impairments, including psychiatric disorders such as schizophrenia. The orbitofrontal cortex (OFC) has been repeatedly associated with catatonia. It presents with an important interindividual morphological variability, with three distinct H-shaped sulcal patterns, types I, II, and III, based on the continuity of the medial and lateral orbital sulci. Types II and III have been identified as neurodevelopmental risk factors for schizophrenia. The sulcal pattern of the OFC has never been investigated in catatonia despite the role of the OFC in the pathophysiology and the neurodevelopmental component of catatonia., Methods: In this context, we performed a retrospective analysis of the OFC sulcal pattern in carefully selected homogeneous and matched subgroups of schizophrenia patients with catatonia ( N  = 58) or without catatonia ( N  = 65), and healthy controls ( N  = 82)., Results: Logistic regression analyses revealed a group effect on OFC sulcal pattern in the left ( χ 2  = 18.1; p  < .001) and right ( χ 2  = 28.3; p  < .001) hemispheres. Catatonia patients were found to have more type III and less type I in both hemispheres compared to healthy controls and more type III on the left hemisphere compared to schizophrenia patients without catatonia., Conclusion: Because the sulcal patterns are indirect markers of early brain development, our findings support a neurodevelopmental origin of catatonia and may shed light on the pathophysiology of this syndrome.

Objectives: Chronic pain is a major health problem given its high prevalence and its multiple consequences on the physical and psychological functioning of patients. It is therefore important to determine the relationship between these consequences and pain management strategies such as activity pacing. This review aimed to examine the association between activity pacing and the level of negative emotions in chronic pain. A second objective was to explore sex differences in this association., Methods: A systematic review of the literature was conducted following the PRISMA guidelines. Three independent reviewers used a combination of keywords within four databases to include studies examining the link between pacing and negative emotions in chronic pain., Results: Pacing was associated with less negative emotions when measured using multidimensional tools, distinguishing it from avoidance, and highlighting the major components of pacing, such as maintaining a constant activity or conserving energy. Data did not allow examination of sex differences., Discussion: Pacing is multidimensional and consists of various strategies of pain management which are not equally associated with negative emotions. It is important to use measures reflecting this conception to strengthen knowledges about the role of pacing in the development of negative emotions., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Transcranial ultrasound stimulation (TUS) has been shown to be a safe and effective technique for non-invasive superficial and deep brain stimulation. Safe and efficient translation to humans requires estimating the acoustic attenuation of the human skull. Nevertheless, there are no international guidelines for estimating the impact of the skull bone. A tissue independent, arbitrary derating was developed by the U.S. Food and Drug Administration to take into account tissue absorption (0.3 dB/cm-MHz) for diagnostic ultrasound. However, for the case of transcranial ultrasound imaging, the FDA model does not take into account the insertion loss induced by the skull bone, nor the absorption by brain tissue. Therefore, the estimated absorption is overly conservative which could potentially limit TUS applications if the same guidelines were to be adopted. Here we propose a three-layer model including bone absorption to calculate the maximum pressure transmission through the human skull for frequencies ranging between 100 kHz and 1.5 MHz. The calculated pressure transmission decreases with the frequency and the thickness of the bone, with peaks for each thickness corresponding to a multiple of half the wavelength. The 95th percentile maximum transmission was calculated over the accessible surface of 20 human skulls for 12 typical diameters of the ultrasound beam on the skull surface, and varies between 40% and 78%. To facilitate the safe adjustment of the acoustic pressure for short ultrasound pulses, such as transcranial imaging or transcranial ultrasound stimulation, a table summarizes the maximum pressure transmission for each ultrasound beam diameter and each frequency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Inc.)

Major depressive disorder (MDD) is the psychiatric disorder with the highest prevalence in the world. Pharmacological antidepressant treatment (AD), such as selective serotonin reuptake inhibitors [SSRI, i.e., fluoxetine (Flx)] is the first line of treatment for MDD. Despite its efficacy, lack of AD response occurs in numerous patients characterizing Difficult-to-treat Depression. ElectroConvulsive Therapy (ECT) is a highly effective treatment inducing rapid improvement in depressive symptoms and high remission rates of ∼50-63% in patients with pharmaco-resistant depression. Nevertheless, the need to develop reliable treatment response predictors to guide personalized AD strategies and supplement clinical observation is becoming a pressing clinical objective. Here, we propose to establish a proteomic peripheral biomarkers signature of ECT response in an anxio/depressive animal model of non-response to AD. Using an emotionality score based on the analysis complementary behavioral tests of anxiety/depression (Elevated Plus Maze, Novelty Suppressed Feeding, Splash Test), we showed that a 4-week corticosterone treatment (35 μg/ml, Cort model) in C57BL/6JRj male mice induced an anxiety/depressive-like behavior. A 28-day chronic fluoxetine treatment (Flx, 18 mg/kg/day) reduced corticosterone-induced increase in emotional behavior. A 50% decrease in emotionality score threshold before and after Flx, was used to separate Flx-responding mice (Flx-R, n = 18), or Flx non-responder mice (Flx-NR, n = 7). Then, Flx-NR mice received seven sessions of electroconvulsive seizure (ECS, equivalent to ECT in humans) and blood was collected before and after ECS treatment. Chronic ECS normalized the elevated emotionality observed in Flx-NR mice. Then, proteins were extracted from peripheral blood mononuclear cells (PBMCs) and isolated for proteomic analysis using a high-resolution MS Orbitrap. Data are available via ProteomeXchange with identifier PXD037392. The proteomic analysis revealed a signature of 33 peripheral proteins associated with response to ECS (7 down and 26 upregulated). These proteins were previously associated with mental disorders and involved in regulating pathways which participate to the depressive disorder etiology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lebeau, Mendez-David, Kucynski-Noyau, Henry, Attali, Plaze, Colle, Corruble, Gardier, Gaillard, Guilloux and David.)

Background and Hypothesis: Motivation deficit is a hallmark of schizophrenia that has a strong impact on their daily life. An alteration of reward processing has been repeatedly highlighted in schizophrenia, but to what extent it involves a deficient amplification of reward representation through conscious processing remains unclear. Indeed, patients with schizophrenia exhibit a disruption of conscious processing, whereas unconscious processing appears to be largely preserved., Study Design: To further explore the nature of motivational deficit in schizophrenia and the implication of consciousness disruption in this symptom, we used a masking paradigm testing motivation both under conscious and unconscious conditions in patients with schizophrenia (n = 31) and healthy controls (n = 32). Participants were exposed to conscious or subliminal coin pictures representing money at stake and were subsequently asked to perform an effort-task by squeezing a handgrip as hard as possible to win this reward., Study Results: We observed a preserved effect of unconscious monetary rewards on force production in both groups, without any significant difference between them. By contrast, in the conscious condition, patients with schizophrenia were less sensitive to rewards than controls. Our results confirm that unconscious incentives have effects on exerted forces in the general population, and demonstrate that patients with schizophrenia exhibit a dissociation between an impaired conscious motivation and a preserved unconscious motivation., Conclusions: These findings suggest the existence of several steps in motivational processes that can be differentially affected and might have implication for patient care., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Catatonia is a severe neuropsychiatric syndrome, usually treated by benzodiazepines and electroconvulsive therapy. However, therapeutic alternatives are limited, which is particularly critical in situations of treatment resistance or when electroconvulsive therapy is not available. Transcranial direct-current stimulation (tDCS) is a promising non-invasive neuromodulatory technique that has shown efficacy in other psychiatric conditions. We present the largest case series of tDCS use in catatonia, consisting of eight patients in whom tDCS targeting the left dorsolateral prefrontal cortex and temporoparietal junction was employed. We used a General Linear Mixed Model to isolate the effect of tDCS from other confounding factors such as time (spontaneous evolution) or co-prescriptions. The results indicate that tDCS, in addition to symptomatic pharmacotherapies such as lorazepam, seems to effectively reduce catatonic symptoms. These results corroborate a synthesis of five previous case reports of catatonia treated by tDCS in the literature. However, the specific efficacy of tDCS in catatonia remains to be demonstrated in a randomized controlled trial. The development of therapeutic alternatives in catatonia is of paramount importance., Competing Interests: JR has held an advisory meeting with representatives from Promentis Pharmaceuticals, Inc. regarding drug development in an unpaid capacity. FV been invited to scientific meetings, consulted and/or served as speaker and received compensation by Lundbeck, Servier, Recordati, Janssen, Otsuka, Chiesi, and LivaNova. RG has received compensation as a member of the scientific advisory board of Janssen, Lundbeck, Roche, SOBI, Takeda. He has served as consultant and/or speaker for Astra Zeneca, Boehringer-Ingelheim, Pierre Fabre, Lilly, Lundbeck, LVMH, MAPREG, Novartis, Otsuka, Pileje, SANOFI, Servier and received compensation, and he has received research support from Servier. MP has served as speaker and received compensation by Lundbeck, Janssen, and LivaNova. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Haroche, Giraud, Vinckier, Amad, Rogers, Moyal, Canivet, Berkovitch, Gaillard, Attali and Plaze.)

Credit assignment is the association of specific instances of reward to the specific events, such as a particular choice, that caused them. Without credit assignment, choice values reflect an approximate estimate of how good the environment was when the choice was made—the global reward state—rather than exactly which outcome the choice caused. Combined transcranial ultrasound stimulation (TUS) and functional magnetic resonance imaging in macaques demonstrate credit assignment–related activity in prefrontal area 47/12o, and when this signal was disrupted with TUS, choice value representations across the brain were impaired. As a consequence, behavior was no longer guided by choice value, and decision-making was poorer. By contrast, global reward state–related activity in the adjacent anterior insula remained intact and determined decision-making after prefrontal disruption.

Introduction: Urgent action is needed to fight the ongoing coronavirus disease 2019 (COVID-19) pandemic by reducing the number of infected cases, contagiousness and severity. Chlorpromazine (CPZ), an antipsychotic from the phenothiazine group, is known to inhibit clathrin-mediated endocytosis and has antiviral activity against severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) and Middle East respiratory syndrome coronavirus. The aim of this in-vitro study was to test CPZ against SARS-CoV-2 in monkey and human cells., Materials and Methods: Monkey VeroE6 cells and human alveolar basal epithelial A549-ACE2 cells were infected with SARS-CoV-2 in the presence of various concentrations of CPZ. Supernatants were harvested at day 2 and analysed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) for the presence of SARS-CoV-2 RNA. Cell viability was assessed in non-infected cells., Results: CPZ was found to have antiviral activity against SARS-CoV-2 in monkey VeroE6 cells, with a half maximal inhibitory concentration (IC 50 ) of 8.2 µM, half maximal cytotoxic concentration (CC 50 ) of 13.5 µM, and selectivity index (SI) of 1.65. In human A549-ACE2 cells, CPZ was also found to have anti-SARS-CoV-2 activity, with IC 50 of 11.3 µM, CC 50 of 23.1 µM and SI of 2.04., Discussion: Although the measured SI values are low, the IC 50 values measured in vitro may translate to CPZ dosages used in routine clinical practice because of the high biodistribution of CPZ in lungs and saliva. Also, the distribution of CPZ in brain could be of interest for treating or preventing neurological and psychiatric forms of COVID-19., Conclusions: These preclinical findings support clinical investigation of the repurposing of CPZ, a drug with mild side effects, in the treatment of patients with COVID-19., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Since the late 2010s, Transcranial Ultrasound Stimulation (TUS) has been used experimentally to carryout safe, non-invasive stimulation of the brain with better spatial resolution than Transcranial Magnetic Stimulation (TMS). This innovative stimulation method has emerged as a novel and valuable device for studying brain function in humans and animals. In particular, single pulses of TUS directed to oculomotor regions have been shown to modulate visuomotor behavior of non-human primates during 100 ms ultrasound pulses. In the present study, a sustained effect was induced by applying 20-s trains of neuronavigated repetitive Transcranial Ultrasound Stimulation (rTUS) to oculomotor regions of the frontal cortex in three non-human primates performing an antisaccade task. With the help of MRI imaging and a frame-less stereotactic neuronavigation system (SNS), we were able to demonstrate that neuronavigated TUS (outside of the MRI scanner) is an efficient tool to carry out neuromodulation procedures in non-human primates. We found that, following neuronavigated rTUS, saccades were significantly modified, resulting in shorter latencies compared to no-rTUS trials. This behavioral modulation was maintained for up to 20 min. Oculomotor behavior returned to baseline after 18-31 min and could not be significantly distinguished from the no-rTUS condition. This study is the first to show that neuronavigated rTUS can have a persistent effect on monkey behavior with a quantified return-time to baseline. The specificity of the effects could not be explained by auditory confounds., (Copyright © 2020 Pouget, Frey, Ahnine, Attali, Claron, Constans, Aubry and Arcizet.)

Employment rate in psychiatry is around 10 to 30%. Cognitive remediation (CR) associated with psychosocial rehabilitation shows good functional outcomes, with a high level of satisfaction in participants provided by tailored CR. However, few studies looked at the long-term outcome in participants who experienced such a program. This retrospective survey examines the outcome of persons having psychiatric diseases 2 to 9 years after being treated with a personalized CR program. The survey included 12 domains with questions relevant to work, studies, before CR (T1) and at the moment of the survey (T2), questions about housing, relatedness, familiar relationships and daily activities at T2. Finally, a narrative interview was included to express feelings of the participants about CR. Sixty-six participants completed the survey, and were treated with neurocognitive or social cognition programs. Their diagnosis was: schizophrenia (80.3%), neurodevelopment disorder (autism as well as genetic or metabolic disease with psychiatric expression) (15.2%) and bipolar disorder (4.5%). The comparison between T1 and T2 showed significant difference for job employment (P < 0.001), even for competitive jobs (p < 0.007), for performing studies (p = 0.033), for practicing a physical activity (0.033) or reading (0.002). Outcome was also examined in reference to the delay from CR to highlight changes in patient characteristics and service delivery over the years. Hence, the total sample was split in two subgroups: CR delivered in 2009-2013 (n = 37); CR delivered in 2014-2016 (n = 29). While in the former group more participants were working (p = 0.037), in the latter group, which was younger (p = 0.04), more participants were studying (p = 0.02). At T2, a majority of persons experienced no relapse, three years (79.1%) to 8 years (56.8%) after CR, when referring to the anamnesis. Concerning subjective perception of CR, participants expressed feelings concerning positive impact on clarity of thought, on cognitive functions, self-confidence, perceiving CR as an efficient help for work and studies. To conclude, even long years after a personalized CR program, good benefits in terms of employment or studies emerge when compared to the status before CR, with good determinants for recovery in terms of leisure or physical activity practice., (Copyright © 2020 Amado, Moualla, Jouve, Brénugat-Herné, Attali, Willard, Rigaut, Malangin, Kern, Meyniel, Gaillard, Plaze, Perquier and Yannick.)

The medial frontal cortex has been linked to voluntary action, but an explanation of why decisions to act emerge at particular points in time has been lacking. We show that, in macaques, decisions about whether and when to act are predicted by a set of features defining the animal's current and past context; for example, respectively, cues indicating the current average rate of reward and recent previous voluntary action decisions. We show that activity in two brain areas-the anterior cingulate cortex and basal forebrain-tracks these contextual factors and mediates their effects on behavior in distinct ways. We use focused transcranial ultrasound to selectively and effectively stimulate deep in the brain, even as deep as the basal forebrain, and demonstrate that alteration of activity in the two areas changes decisions about when to act., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Interactions between social cognition and symptoms of schizophrenia have been investigated, but mostly component by component. Here we tested the assumption that two categories of deficits exist depending on clinical profiles, one corresponding to a defect in social cognition - "under-social cognition" - and one corresponding to excessive attributions leading to social cognitive impairments - "over-social cognition". To conduct the investigation, we performed a Hierarchical Clustering Analysis using positive and negative symptoms in seventy patients with schizophrenia and we compared the clusters obtained to a group of healthy controls on social cognitive measures. We distinguished two social cognitive profiles based on prevailing symptoms for emotion processes and Theory of Mind. Actually, patients with negative symptoms showed lower performances in emotion recognition task than both those with positive symptoms and controls. Concerning Theory of Mind, patients with positive symptoms had a significant tendency to make over interpretative errors than both patients with negative symptoms and controls. For other processes assessed, further explorations are needed. Actually, concerning social perception and knowledge both patients' groups presented significant impairments compared to controls. Assessment of attribution bias showed that patients in the positive group presented a significant hostility bias and a higher intentionality score compared to healthy controls. These results favor the existence of different categories of impairments depending more on the clinical characteristics of patients than on nosographical categories, but further investigations are now necessary to specify these profiles. It nevertheless showed the importance of assessing symptoms in relationship with cognitive functioning.

Droplet digital polymerase chain reaction (ddPCR) is a novel platform for exact quantification of DNA which holds great promise in clinical diagnostics. It is increasingly popular due to its digital nature, which provides more accurate quantification and higher sensitivity than traditional real-time PCR. However, clinical adoption has been slowed in part by the lack of software tools available for analyzing ddPCR data. Here, we present ddpcr - a new R package for ddPCR visualization and analysis. In addition, ddpcr includes a web application (powered by the Shiny R package) that allows users to analyze ddPCR data using an interactive graphical interface., Competing Interests: No competing interests were disclosed.

A need exists for robust and cost-effective assays to detect a single or small set of actionable point mutations, or a complete set of clinically informative mutant alleles. Knowledge of these mutations can be used to alert the clinician to a rare mutation that might necessitate more aggressive clinical monitoring or a personalized course of treatment. An example is BRAF, a (proto)oncogene susceptible to either common or rare mutations in codon V600 and adjacent codons. We report a diagnostic technology that leverages the unique capabilities of droplet digital PCR to achieve not only accurate and sensitive detection of BRAF(V600E) but also all known somatic point mutations within the BRAF V600 codon. The simple and inexpensive two-well droplet digital PCR assay uses a chimeric locked nucleic acid/DNA probe against wild-type BRAF and a novel wild-type-negative screening paradigm. The assay shows complete diagnostic accuracy when applied to formalin-fixed, paraffin-embedded tumor specimens from metastatic colorectal cancer patients deficient for Mut L homologue-1., (Copyright © 2016 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.)

Purpose: Trabecular bone microarchitecture is made of a complex network of plate and rod structures evolving with age and disease. The purpose of this article is to propose a new 3D local analysis method for the quantitative assessment of parameters related to the geometry of trabecular bone microarchitecture., Methods: The method is based on the topologic classification of the medial axis of the 3D image into branches, rods, and plates. Thanks to the reversibility of the medial axis, the classification is next extended to the whole 3D image. Finally, the percentages of rods and plates as well as their mean thicknesses are calculated. The method was applied both to simulated test images and 3D micro-CT images of human trabecular bone., Results: The classification of simulated phantoms made of plates and rods shows that the maximum error in the quantitative percentages of plate and rods is less than 6% and smaller than with the structure model index (SMI). Micro-CT images of human femoral bone taken in osteoporosis and early or advanced osteoarthritis were analyzed. Despite the large physiological variability, the present method avoids the underestimation of rods observed with other local methods. The relative percentages of rods and plates were not significantly different between osteoarthritis and osteoporotic groups, whereas their absolute percentages were in relation to an increase of rod and plate thicknesses in advanced osteoarthritis with also higher relative and absolute number of nodes., Conclusions: The proposed method is model-independent, robust to surface irregularities, and enables geometrical characterization of not only skeletal structures but entire 3D images. Its application provided more accurate results than the standard SMI on simple simulated phantoms, but the discrepancy observed on the advanced osteoarthritis group raises questions that will require further investigations. The systematic use of such a local method in the characterization of trabecular bone samples could provide new insight in bone microarchitecture changes related to bone diseases or to those induced by drugs or therapy.