About

The Laboratory of Mathematics in Imaging (LMI) is focused on the application of mathematical theory, analysis, modeling, and signal processing to medical imaging. Research projects within the group cover both novel theoretical contributions and translational clinical efforts. The research team combine strengths in computer science and mathematics with radiology, neuroscience, and novel MRI sequence developmentLearn more

Recent Publications

Increased pulmonary artery diameter is associated with reduced FEV in former World Trade Center workers

de la Hoz RE, Jeon Y, Reeves AP, San José Estépar R, Liu X, Doucette JT, Celedón JC, Nolan A. Increased pulmonary artery diameter is associated with reduced FEV in former World Trade Center workers. Clin Respir J. 2019.Abstract
RATIONALE: Occupational exposures at the WTC site after September 11, 2001 have been associated with several presumably inflammatory lower airway diseases. Pulmonary arterial enlargement, as suggested by an increased ratio of the diameter of the pulmonary artery to the diameter of the aorta (PAAr) has been reported as a computed tomographic (CT) scan marker of adverse respiratory health outcomes, including WTC-related disease. In this study, we sought to utilize a novel quantitative CT (QCT) measurement of PAAr to test the hypothesis that an increased ratio is associated with FEV below each subject's statistically determined lower limit of normal (FEV
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Association of Choroid Plexus Enlargement With Cognitive, Inflammatory, and Structural Phenotypes Across the Psychosis Spectrum

Lizano P, Lutz O, Ling G, Lee AM, Eum S, Bishop JR, Kelly S, Pasternak O, Clementz B, Pearlson G, et al. Association of Choroid Plexus Enlargement With Cognitive, Inflammatory, and Structural Phenotypes Across the Psychosis Spectrum. Am J Psychiatry. 2019;176 (7) :564-572.Abstract
OBJECTIVE: The choroid plexus is an important physiological barrier and produces CSF and neurotrophic, angiogenic, and inflammatory factors involved in brain development. Choroid plexus abnormalities have been implicated in both schizophrenia and bipolar disorder. A previous choroid plexus transcriptomic analysis of schizophrenia identified an upregulation of immune and inflammatory genes that correlated with peripheral inflammatory markers. The purpose of this study was to examine choroid plexus volume in probands across the psychosis spectrum and in their first-degree and axis II cluster A relatives, as well as choroid plexus familiality and choroid plexus covariance with clinical, cognitive, brain, and peripheral marker measures. METHODS: Choroid plexus volume was quantified (using FreeSurfer) in psychosis probands, their first-degree and axis II cluster A relatives, and healthy control subjects, organized by DSM-IV-TR diagnosis. Analyte, structural connectivity, and genotype data were collected from a subset of study subjects. RESULTS: Choroid plexus volume was significantly larger in probands compared with first-degree relatives or healthy control subjects; first-degree relatives had intermediate enlargement compared with healthy control subjects; and total choroid plexus volume was significantly heritable. Larger volume was associated with worse cognition, smaller total gray matter and amygdala volume, larger lateral ventricle volume, and lower structural connectivity in probands. Associations between larger volume and higher levels of interleukin 6 in probands was also observed. CONCLUSIONS: These findings suggest the involvement of the choroid plexus across the psychosis spectrum with a potential pathophysiological mechanism involving the neuroimmune axis, which functions in maintaining brain homeostasis and interacting with the peripheral immune and inflammatory system. The choroid plexus may be an important target in future research.
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An MRI Pilot Study of Intravenous Glyburide in Traumatic Brain Injury

Eisenberg HM, Shenton ME, Pasternak O, Simard MJ, Okonkwo DO, Aldrich C, He F, Jain S, Hayman E. An MRI Pilot Study of Intravenous Glyburide in Traumatic Brain Injury. J Neurotrauma. 2019.Abstract
Preclinical studies of traumatic brain injury (TBI) show that Glyburide reduces edema and hemorrhagic progression of contusions. We conducted a small Phase 2, three-institution, randomized placebo-controlled trial of subjects with TBI, to assess the safety and efficacy of intravenous (IV) Glyburide. Twenty-eight subjects were randomized and underwent a 72-hour infusion of IV Glyburide or placebo, beginning within 10 hours of trauma. Of the 28 subjects, 25 had Glasgow Coma Scale scores of 6-10, and 14 had contusions. There were no differences in adverse or severe adverse events between groups. The MRI percent change at 72-168 hours from screening/baseline was compared between the Glyburide and Placebo groups. Analysis of contusions (7 per group) showed that lesion volumes (hemorrhage plus edema) increased 1036% with placebo vs. 136% with Glyburide (P=0.15), and that hemorrhage volumes increased 11.6% with placebo but decreased 29.6% with Glyburide (P=0.62). Three diffusion MRI measures of edema were quantified: mean diffusivity (MD), free water (FW), and tissue MD (MDt), corresponding to overall, extracellular and intracellular water, respectively. The percent change with time for each measure was compared in lesions (n=14) vs. uninjured white matter (n=24) in subjects receiving placebo (n=20) or Glyburide (n=18). For placebo, the percent change in lesions for all 3 measures was significantly different compared to uninjured white matter (ANOVA, P<0.02), consistent with worsening of edema in untreated contusions. In contrast, for Glyburide, the percent change in lesions for all 3 measures was not significantly different compared to uninjured white matter. Further study of IV Glyburide in contusion-TBI is warranted.
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Linear, planar and spherical tensor-valued diffusion MRI data by free waveform encoding in healthy brain, water, oil and liquid crystals

Szczepankiewicz F, Hoge S, Westin C-F. Linear, planar and spherical tensor-valued diffusion MRI data by free waveform encoding in healthy brain, water, oil and liquid crystals. Data Brief. 2019;25 :104208.Abstract
Recently, several biophysical models and signal representations have been proposed for microstructure imaging based on tensor-valued, or multidimensional, diffusion MRI. The acquisition of the necessary data requires non-conventional pulse sequences, and data is therefore not available to the wider diffusion MRI community. To facilitate exploration and development of analysis techniques based on tensor-valued diffusion encoding, we share a comprehensive data set acquired in a healthy human brain. The data encompasses diffusion weighted images using linear, planar and spherical diffusion tensor encoding at multiple b-values and diffusion encoding directions. We also supply data acquired in several phantoms that may support validation. The data is hosted by GitHub: https://github.com/filip-szczepankiewicz/Szczepankiewicz_DIB_2019.
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Association of Obesity with Quantitative Chest CT Measured Airway Wall Thickness in WTC Workers with Lower Airway Disease

de la Hoz RE, Liu X, Celedón JC, Doucette JT, Jeon Y, Reeves AP, San José Estépar R. Association of Obesity with Quantitative Chest CT Measured Airway Wall Thickness in WTC Workers with Lower Airway Disease. Lung. 2019;197 (4) :517-522.Abstract
BACKGROUND: We previously reported that wall area percent (WAP), a quantitative CT (QCT) indicator of airway wall thickness and, presumably, inflammation, is associated with adverse longitudinal expiratory flow trajectories in WTC workers, but that obesity and weight gain also seemed to be independently predictive of the latter. Previous studies have reported no association between WAP and obesity, so we investigated that association in nonsmoking WTC-exposed individuals and healthy unexposed controls. METHODS: We assessed WAP using the Chest Imaging Platform QCT system in a segmental bronchus in 118 former WTC workers, and 89 COPDGene® WTC-unexposed and asymptomatic subjects. We used multiple regression to model WAP vs. body mass index (BMI) in the two groups, adjusting for important subject and CT image characteristics. RESULTS: Unadjusted analyses revealed significant differences between the two groups with regards to WAP, age, gender, scan pixel spacing and slice interval, but not BMI or total lung capacity. In adjusted analysis, there was a significant interaction between BMI and WTC exposure on WAP. BMI was significantly and positively associated with WAP in the WTC group, but not in the COPDGene® group, but stratified analyses revealed that the effect was significant in WTC subjects with clinical evidence of lower airway disease (LAD). DISCUSSION: Unlike non-diseased subjects, BMI was significantly associated with WAP in WTC workers and, in stratified analyses, the association was significant only among those with LAD. Our findings suggest that this adverse effect of obesity on airway structure and inflammation may be confined to already diseased individuals.
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