Leorah Freeman’s research while affiliated with University of Texas at Austin and other places

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Publications (47)


Health outcomes and healthcare service use in older adults with and without multiple sclerosis: a plain language summary
  • Article

May 2025

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1 Read

Neurodegenerative Disease Management

Leorah Freeman

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Jia Zhou

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Reliability of Central Vein Sign Imaging With 3T FLAIR* in a Multicenter Study

January 2025

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52 Reads

Journal of neuroimaging: official journal of the American Society of Neuroimaging

Background and Purpose The central vein sign (CVS) is a diagnostic imaging biomarker for multiple sclerosis (MS). FLAIR* is a combined MRI contrast that provides high conspicuity for CVS at 3 Tesla (3T), enabling its sensitive and accurate detection in clinical settings. This study evaluated whether CVS conspicuity of 3T FLAIR* is reliable across imaging sites and MRI vendors and whether gadolinium (Gd) contrast increases CVS conspicuity. Methods A cross‐sectional, multicenter study recruited adults referred for possible diagnosis of MS at 10 sites. FLAIR* contrast was generated using high‐resolution T2*‐weighted (acquired pre‐ and post‐injection of Gd) and T2‐weighted fluid‐attenuated inversion recovery (T2‐FLAIR) brain images at 3T from two MRI vendors. Lesions and veins were segmented to compute lesion‐to‐vein contrast‐to‐noise ratio (CNR lesion‐to‐vein ), a quantitative measure of CVS conspicuity. CNR lesion‐to‐vein measures for pre‐ and post‐Gd FLAIR* were compared across sites and vendors. Results Eighty‐seven participants from nine sites were included in the analysis. There was no significant difference in mean CNR lesion‐to‐vein between sites for pre‐Gd ( p ‐value = 0.07) or post‐Gd ( p ‐value = 0.27) FLAIR*. There were also no significant differences between vendors for pre‐Gd ( p ‐value = 0.10) or post‐Gd ( p ‐value = 0.31) FLAIR*. Patient‐level pairwise differences in CNR lesion‐to‐vein between pre‐Gd and post‐Gd FLAIR* revealed a significant increase for post‐Gd FLAIR* ( p ‐value < 0.001). Conclusions CVS conspicuity on 3T FLAIR* is consistent across imaging sites and MRI vendors. Moreover, Gd‐based contrast agent significantly improved CVS conspicuity on 3T FLAIR*. These findings support the implementation of FLAIR* in clinical settings for MS.



Multicenter validation of automated detection of paramagnetic rim lesions on brain MRI in multiple sclerosis

October 2024

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34 Reads

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2 Citations

Journal of neuroimaging: official journal of the American Society of Neuroimaging

Background and Purpose Paramagnetic rim lesions (PRLs) are an MRI biomarker of chronic inflammation in people with multiple sclerosis (MS). PRLs may aid in the diagnosis and prognosis of MS. However, manual identification of PRLs is time‐consuming and prone to poor interrater reliability. To address these challenges, the Automated Paramagnetic Rim Lesion (APRL) algorithm was developed to automate PRL detection. The primary objective of this study is to evaluate the accuracy of APRL for detecting PRLs in a multicenter setting. Methods We applied APRL to a multicenter dataset, which included 3‐Tesla MRI acquired in 92 participants (43 with MS, 14 with clinically isolated syndrome [CIS]/radiologically isolated syndrome [RIS], 35 without RIS/CIS/MS). Subsequently, we assessed APRL's performance by comparing its results with manual PRL assessments carried out by a team of trained raters. Results Among the 92 participants, expert raters identified 5637 white matter lesions and 148 PRLs. The automated segmentation method successfully captured 115 (78%) of the manually identified PRLs. Within these 115 identified lesions, APRL differentiated between manually identified PRLs and non‐PRLs with an area under the curve (AUC) of .73 (95% confidence interval [CI]: [.68, .78]). At the subject level, the count of APRL‐identified PRLs predicted MS diagnosis with an AUC of .69 (95% CI: [.57, .81]). Conclusion Our study demonstrated APRL's capability to differentiate between PRLs and lesions without paramagnetic rims in a multicenter study. Automated identification of PRLs offers greater efficiency over manual identification and could facilitate large‐scale assessments of PRLs in clinical trials.


Sample selection framework. Footnote: DMT = Disease-Modifying Therapy; MRI = Magnetic Resonance Imaging; a–≥3 claims with a diagnosis of MS or at least one claim for an MS-indicated DMT in 2018; b– People identified with a claim for the drug natalizumab without any MS diagnosis; c– No history of an MS-indicated DMT in the year prior to their date of index into the study; d– Any claim for an MRI of the brain, orbits, cervical spine, or thoracic spine; e– Missing data included sex and US Census Region
Plot of adjusted odds ratios of MRI use and DMT switches among people with multiple sclerosis. Footnote: CNS = Central Nervous System; Crude = Includes people with MS who received any number of MRIs of the CNS; DMT = Disease-Modifying Therapy; MRI = Magnetic Resonance Imaging; a– Number of MRIs reported of distinct CNS locations including the brain, orbits, cervical spine, or thoracic spine within one month of the first reported MRI; b - Odds ratios of MRI use and DMT switches derived from logistic regressions adjusting for age and relapse at index
Correlation between MRI utilization and therapy switches in disease-modifying treatments for multiple sclerosis
  • Article
  • Publisher preview available

October 2024

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14 Reads

Neuroradiology

Background and objectives Studies measuring the role of magnetic resonance imaging (MRI) in therapeutic decision-making are rare in people with multiple sclerosis (pwMS). This study aimed to measure the association between MRI utilization and disease-modifying therapy (DMT) switches in pwMS. Methods This retrospective cohort study identified pwMS in 2018 from a de-identified national claims database. PwMS who received MRI in 2018 were compared to pwMS not receiving MRI in 2018. PwMS were observed for six months to assess the incidence of DMT switches. Results The study sample consisted of 11,972 pwMS. 3,931 (32.8%) pwMS received at least one MRI in 2018. Overall, MRI utilization increased the odds of switching DMT (OR = 1.49, 1.79, and 3.01 for 1, 2, and ≥ 3 CNS locations imaged). For those on injectable or platform DMT, any MRI utilization increased the odds of switching DMT (OR = 1.54, 2.00, and 3.48 for 1, 2, and ≥ 3 locations imaged). For those on oral DMT, only receiving MRI of 2 or ≥ 3 locations increased the odds of a DMT switch (OR = 1.36, 1.89, and 2.40 for 1, 2, and ≥ 3 locations). Finally, for pwMS on infusible therapies, there was little evidence that MRI changed the odds of a DMT switch. Discussion Among pwMS on injectable or oral DMT, imaging more CNS locations increased the odds of switching DMT after adjusting for age and relapse incidence. For pwMS on high-efficacy infusible DMTs, MRI did not change the odds of switching DMT but remains essential for safety monitoring.

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Multicenter Automated Central Vein Sign Detection Performs as Well as Manual Assessment for the Diagnosis of Multiple Sclerosis

September 2024

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39 Reads

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3 Citations

American Journal of Neuroradiology

Background and purpose: The central vein sign (CVS) is a proposed diagnostic imaging biomarker for multiple sclerosis (MS). The proportion of white matter lesions exhibiting the CVS (CVS+) is higher in patients with MS compared to its radiological mimics. Evaluation for CVS+ lesions in prior studies have been performed by manual rating, an approach that is time-consuming and has variable inter-rater reliability. Accurate automated methods would facilitate efficient assessment for CVS. The objective of this study was to compare the performance of an automated CVS detection method with manual rating for the diagnosis of MS. Materials and methods: 3T MRI was acquired in 86 participants undergoing evaluation for MS in a 9-site multicenter study. Participants presented with either typical or atypical clinical syndromes for MS. An automated CVS detection method was employed and compared to manual rating, including total CVS+ proportion and a simplified counting method in which experts visually identified up to 6 CVS+ lesions using FLAIR* contrast (a voxel-wise product of T2 FLAIR and post-contrast T2*-EPI images). Results: Automated CVS processing was completed in 79 of 86 participants (91%), of whom 28 (35%) fulfilled the 2017 McDonald criteria at the time of imaging. The area under the receiver-operator characteristic curve (AUC) for discrimination between participants with and without MS for the automated CVS approach was 0.78 (95% confidence interval: [0.67,0.88]). This was not significantly different from simplified manual counting methods (select6*) (0.80 [0.69,0.91]) or manual assessment of total CVS+ proportion (0.89 [0.82,0.96]). In a sensitivity analysis excluding 11 participants whose MRI exhibited motion artifact, the AUC for the automated method was 0.81 [0.70,0.91], which was not statistically different from that for select6* (0.79 [0.68,0.92]) or manual assessment of total CVS+ proportion (0.89 [0.81,0.97]). Conclusions: Automated CVS assessment was comparable to manual CVS scoring for differentiating patients with MS from those with other diagnoses. Large, prospective, multicenter studies utilizing automated methods and enrolling the breadth of disorders referred for suspicion of MS are needed to determine optimal approaches for clinical implementation of an automated CVS detection method. Abbreviations: CVS= central vein sign; CVS+ = white matter lesions exhibiting the CVS; MRI = magnetic resonance imaging; MS = multiple sclerosis; T2 FLAIR = T2 fluid-attenuated inversion recovery; T2*-EPI = T2*-weighted 3D echo planar imaging; FLAIR* = a voxel-wise product of T2 FLAIR and post-contrast T2*-EPI images; select6* = simplified counting method in which experts visually identified up to 6 CVS+ lesions on FLAIR* imaging.


Demographic, clinical, and radiological data of study participants at the time of initial assessment.
Biomarker results for participants diagnosed with multiple sclerosis at initial assessment and at 12-month follow-up.
Sensitivity, specificity, positive and negative predictive values of Select-3, Select-6, oligoclonal bands, or combinations, for diagnosis of multiple sclerosis.
Diagnostic performance of central vein sign versus oligoclonal bands for multiple sclerosis

September 2024

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62 Reads

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6 Citations

Background Cerebrospinal fluid (CSF) oligoclonal bands (OCB) are a diagnostic biomarker in multiple sclerosis (MS). The central vein sign (CVS) is an imaging biomarker for MS that may improve diagnostic accuracy. Objectives The objective of the study is to examine the diagnostic performance of simplified CVS methods in comparison to OCB in participants with clinical or radiological suspicion for MS. Methods Participants from the CentrAl Vein Sign in MS (CAVS-MS) pilot study with CSF testing were included. Select-3 and Select-6 (counting up to three or six CVS+ lesions per scan) were rated on post-gadolinium FLAIR* images. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value for Select-3, Select-6, OCB, and combinations thereof were calculated for MS diagnosis at baseline and at 12 months. Results Of 53 participants, 25 were OCB+. At baseline, sensitivity for MS diagnosis was 0.75 for OCB, 0.83 for Select-3, and 0.71 for Select-6. Specificity for MS diagnosis was 0.76 for OCB, 0.48 for Select-3, and 0.86 for Select-6. At 12 months, PPV for MS diagnosis was 0.95 for Select-6 and 1.00 for Select-6 with OCB+ status. Discussion Results suggest similar diagnostic performance of simplified CVS methods and OCB. Ongoing studies will refine whether CVS could be used in replacement or in conjunction with OCB.


Age-adjusted prevalence of CNS-active polypharmacy among people with multiple sclerosis in the United States from 2008 to 2021 by sex.
aThe concurrent use of ≥ 3 CNS-active drugs with at least > 30 days of contiguous exposure.
bThe concurrent use of ≥ 3 CNS-active drugs with > 30 and <180 days of contiguous exposure.
cThe concurrent use of ≥ 3 CNS-active drugs with ≥ 180 days of contiguous exposure.
Age-adjusted prevalence of CNS-active polypharmacy among people with multiple sclerosis in the United States from 2008 to 2021 by sex with prevalence of CNS-active drug use by class (a) female and (b) male.
aThe concurrent use of ≥ 3 CNS-active drugs with at least > 30 days of contiguous exposure.
Note. 95% CI not shown for estimates of drug class prevalence.
Age-adjusted prevalence estimates of CNS-active polypharmacy by sex, year, and chronicity from 2008 to 2021.
Descriptive statistics of people with multiple sclerosis in 2021 by sex and CNS-active polypharmacy status.
Person-days, CNS-active polypharmacy days, number of concurrent CNS-active-drugs prescribed, and number of prescribers and prescriber types prescribing drugs contributing to CNS-active polypharmacy in people with multiple sclerosis in 2021.
Trends in central nervous system-active polypharmacy among people with multiple sclerosis

May 2024

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17 Reads

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2 Citations

Background People with multiple sclerosis (pwMS) are at risk of concurrently using multiple central nervous system (CNS)-active drugs, yet the prevalence of CNS-active polypharmacy remains unmeasured in pwMS. Objective The objective is to measure the prevalence of CNS-active polypharmacy in pwMS. Methods This serial, cross-sectional study measured CNS-active polypharmacy in people with MS in the United States from 2008 to 2021 using insurance claims data. CNS-active polypharmacy was defined as the concurrent prescription of ⩾3 CNS-active drugs for >30 continuous days. CNS-active drugs included antidepressants, antiepileptics, antipsychotics, benzodiazepines, nonbenzodiazepine benzodiazepine receptor agonist hypnotics, opioids, and skeletal muscle relaxants. Results The number of subjects included at each time point ranged from 23,917 subjects in 2008 to 55,797 subjects in 2021. In 2021, subjects with CNS-active polypharmacy were more likely to be 46–65 years of age and have CNS-related comorbidities compared to those without CNS-active polypharmacy. From 2008 to 2021, the age-adjusted prevalence of CNS-active polypharmacy among female subjects increased from 19.8% (95% confidence interval (CI) = 19.1–20.4) to 26.4% (95% CI = 25.9–26.8) versus 15.9% (95% CI = 14.8–17.0) to 18.6% (95% CI = 17.9–19.2) in male subjects. Conclusion The prevalence of CNS-active polypharmacy has increased among people with MS with a growing disparity by sex.


Overview of the study design. The administrative health claims data were filtered by a validated MS phenotyping algorithm to identify MS patients. The patients were further filtered by requiring at least 2 years of clinical data, age at baseline (within 18 and 65 years), and estimations of proportion of days covered (PDC) greater than 0.8. Outcomes were measured by detecting MS relapses with a validated algorithm. The causal inference model adjusted for confounding factors and selection bias.
CONSORT flow diagram of emulated RCTs with claims data. This CONSORT flow diagram shows the process of cohort identification in our retrospective case–control study, including the number of patients included and excluded at each step of the analyses.
Estimated ARR and 95% CIs in all trials. Each of the emulated clinical trials included the same respective cases and censored groups and different randomly sampled controls from the respective potential control groups. In red, cases represent the estimated ARR for MS patients with montelukast treatment. In blue, controls represent the estimated counterfactual ARR for MS patients without montelukast treatment. Bootstrap sampling was performed to calculate the 95% CIs of each trial: (a, b) CDM results are shown, (c, d) PharMetrics Plus for Academics results are shown, (a, c) each trial represents relapses identified by the Marriott algorithm, and (b, d) each trial represents relapses identified by the Chastek algorithm.
Demographics, comorbidities, and MS DMTs of pwMS a .
Average number of relapses and percentage reductions in emulated clinical trials.
Montelukast as a repurposable additive drug for standard-efficacy multiple sclerosis treatment: Emulating clinical trials with retrospective administrative health claims data

April 2024

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39 Reads

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2 Citations

Background Effective and safe treatment options for multiple sclerosis (MS) are still needed. Montelukast, a leukotriene receptor antagonist (LTRA) currently indicated for asthma or allergic rhinitis, may provide an additional therapeutic approach. Objective The study aimed to evaluate the effects of montelukast on the relapses of people with MS (pwMS). Methods In this retrospective case–control study, two independent longitudinal claims datasets were used to emulate randomized clinical trials (RCTs). We identified pwMS aged 18–65 years, on MS disease-modifying therapies concomitantly, in de-identified claims from Optum’s Clinformatics® Data Mart (CDM) and IQVIA PharMetrics® Plus for Academics. Cases included 483 pwMS on montelukast and with medication adherence in CDM and 208 in PharMetrics Plus for Academics. We randomly sampled controls from 35,330 pwMS without montelukast prescriptions in CDM and 10,128 in PharMetrics Plus for Academics. Relapses were measured over a 2-year period through inpatient hospitalization and corticosteroid claims. A doubly robust causal inference model estimated the effects of montelukast, adjusting for confounders and censored patients. Results pwMS treated with montelukast demonstrated a statistically significant 23.6% reduction in relapses compared to non-users in 67.3% of emulated RCTs. Conclusion Real-world evidence suggested that montelukast reduces MS relapses, warranting future clinical trials and further research on LTRAs’ potential mechanism in MS.



Citations (30)


... Attention should be paid to patients with Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), who may present with a challenging number of CVS-positive lesions (almost 33%, according to the study of Cagol et al.) [106]. In patients with suspected MS, adding at least one CVSpositive lesion to the MRI DIS criteria increases the diagnostic accuracy for MS from 78 to 86% [113], as reported with OCB [27]. Maggi et al. [114] showed in their study of 51 challenging cases that using the CVS could improve MS diagnosis in more than 90% of the cases. ...

Reference:

The Kappa Free Light Chains Index and Central Vein Sign: Two New Biomarkers for Multiple Sclerosis Diagnosis
Incorporation of the Central Vein Sign into the McDonald Criteria
  • Citing Article
  • November 2024

Multiple Sclerosis and Related Disorders

... 111 Methods to overcome this limitation have been proposed, including combining QSM with myelin-specific imaging markers 111 and biophysical modeling to separate susceptibility sources (χ-separation). 112 Given the time-consuming process of manually identifying PRLs, automatic detection methods on 3 T MRI images implementing artificial intelligence/machine learning methods have been recently proposed for both phase (i.e., RimNet, 113 and APRL 114,115 ) and QSM images (i.e., QSMRim-Net 116 ). While more technical development and large-scale validation studies are still needed, these initial proof-of-concept methods open the path for future deployment of automated PRL detection in the clinical setting. ...

Multicenter validation of automated detection of paramagnetic rim lesions on brain MRI in multiple sclerosis
  • Citing Article
  • October 2024

Journal of neuroimaging: official journal of the American Society of Neuroimaging

... With the development of susceptibility-based magnetic resonance imaging, observing these central veins in MS plaques became possible using ultrahighfield MRI [86][87][88] and, later on, 3T and even 1.5T MRI [89][90][91][92]. To our knowledge, there is only one report of the CVS in MS lesions located in the spinal cord [93], although there is pathological evidence of a central vein in spinal cord lesions. ...

Multicenter Automated Central Vein Sign Detection Performs as Well as Manual Assessment for the Diagnosis of Multiple Sclerosis
  • Citing Article
  • September 2024

American Journal of Neuroradiology

... Recently, Toljan et al. compared OCB with CVS reporting similar sensitivity of the rule of 6 and OCB (71% vs 75%, respectively) with increased specificity of the CVS compared with OCB (86% vs 76%). 27 We are encouraged by the result showing high specificity of the CVS in a study which intentionally enrolled MS and non-MS cases. In another study by the same group, 28 the rule of 6 showed 65% sensitivity and 98% specificity in correctly classifying patients with MS. ...

Diagnostic performance of central vein sign versus oligoclonal bands for multiple sclerosis

... Outros autores abordaram os impactos dos medicamentos de alto risco na saúde mental, como os antidepressivos e benzodiazepínicos, e sua associação com o agravamento da depressão e comprometimento cognitivo (Naizer et al. 2024;Huang et al., 2021;Freire et al., 2022). ...

Trends in central nervous system-active polypharmacy among people with multiple sclerosis

... Additional evaluations to be conducted as part of the study are to include evaluation of motor and non-motor functions, changes in dopaminergic treatment, safety, and plasma and CSF levels of inflammatory, leukotriene and neurodegeneration markers as well as MTK. Most importantly in the context of MS, a recent retrospective case-control study suggests that MTK reduces relapses in patients with MS (Manuel et al., 2024). This study used two large datasets from a total of 118,642 people, with 691 of them being adherent on MTK. ...

Montelukast as a repurposable additive drug for standard-efficacy multiple sclerosis treatment: Emulating clinical trials with retrospective administrative health claims data

... Participants who completed any of the four RMS trials of ozanimod 3-7 were eligible to enroll in DAYBREAK (NCT02576717), a Phase III, singlearm, OLE study of ozanimod 0.92 mg/day. 23,24 An interim analysis of the DAYBREAK OLE showed that ozanimod treatment provided sustained control of disability progression for up to 5 years in participants with RMS. 25 Reproduced with permission from Zivadinov et al. 22 For least squares mean change, a mixed-effect model with repeated measures was used with the baseline volume, baseline age, and time point (treated as a categorical variable) as fixed effects; and individual patients as a random effect. ...

Relapse-associated Worsening and Progression-independent Relapse Activity in Ozanimod-treated Participants with Relapsing Multiple Sclerosis from the RADIANCE and DAYBREAK Trials (P6-6.014)
  • Citing Article
  • April 2024

Neurology

... SPAK has also been linked to other CNS disorders, including schizophrenia and epilepsy [17,18]. Notably, clinical imaging studies reveal increased ChP volume in MS patients compared to healthy controls [19][20][21]. Given SPAK's established involvement in cell volume regulation [22], we hypothesize that ChP SPAK signaling plays a key role in MS pathology. ...

Choroid plexus volume differentiates MS from its mimics

... The majority of current cohorts reported the CVS prevalence in MS or other less typical demyelinating disorders in 3 T or 7 T magnetic field strength, as the magnitude of susceptibility rises higher compared to lower magnetic field strength. Thus, the contemporary CVS analysis methods like select-n* or percentage-based CVS+ ratio were proposed in 3 T and 7 T magnetic field strengths [9][10][11]. Occasionally, the performance of the 1.5 T magnetic field strength was investigated, and a few studies reported promising outcomes from Epi-T2* in identifying the CVS, despite the lower susceptibility sensitivity of Epi-T2* at 1.5 T magnetic field strength. ...

A multicenter pilot study evaluating simplified central vein assessment for the diagnosis of multiple sclerosis

... In addition, the contrast in synthetic images is prone to deviate from those of acquired images as the physical effects such as flow, diffusion, magnetization transfer, and field susceptibility are not comprehensively incorporated in the imaging sequence and signal equation [41]. Including some of these effects may reduce the differences in the contrast of the synthetic and acquired images, but could decrease the signal-to-noise ratio or increase the scan duration of the quantitative imaging protocols [42]. Consequently, synthetic images generally have subtle differences in image contrast compared to conventional weighted images [43]. ...

Correcting synthetic MRI contrast-weighted images using deep learning
  • Citing Article
  • December 2023

Magnetic Resonance Imaging