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Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UC San Francisco Electronic Theses and Dissertations (2015)

Many individuals with alcohol use disorders (AUD) are chronic cigarette smokers, and the specific contributions of both chronic drinking and smoking to brain injury need to be better understood. A previous analysis of 1.5T diffusion tensor imaging data by Tract-Based Spatial Statistics (TBSS) found significant microstructural injury of brain white matter in 11 smoking alcoholics at 1 week of abstinence. The objectives of this study are to reproduce the 1.5T study with corresponding 4T MRI data from a larger sample of alcoholics (ALC) in recovery and to test the effects of cigarette smoking on microstructural integrity of brain white matter. Corpus callosum, cingulum bundle, fornix, and medial forebrain bundle were chosen as a priori regions of interest (ROIs). After TBSS analyses, family-wise error (FWE)-corrected t-statistics showed significant fractional anisotropy (FA) deficits in smoking ALC (sALC) at 1 week of abstinence compared with nonsmoking healthy controls within corpus callosum (body, genu, and splenium), fornix, and medial forebrain bundle, largely replicating the findings at 1.5T. Exploratory uncorrected t-statistics found significant FA deficits in sALC at 1 month of abstinence compared with smoking controls within cingulum bundle, body of corpus callosum, fornix, and medial forebrain bundle; no regional FA difference remained significant after FWE correction. Exploratory uncorrected t-statistics found significant FA decreases and increases in smoking versus non-smoking alcoholics, as well as regional FA decreases in smoking versus non-smoking healthy controls; none of these smoking effects, however, remained significant after FWE correction. The analyses suggest that white matter microstructural integrity in alcoholics is compromised at 1 week of abstinence and may have recovered after 1 month of abstinence, and chronic cigarette smoking may reduce microstructural integrity in both alcoholics and healthy controls.

    Cover page: Microstructural integrity of brain white matter in different substance using populations: Diffusion Tensor Imaging analysis of 4 Tesla MRI data
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2018)
    Identification of neural correlates of relapse to alcohol after treatment is clinically important as it may inform better substance abuse treatment. Few studies have specifically analyzed the white matter microstructure in treatment seekers as it might relate to relapse risk versus long-term abstinence. Using 4 Tesla diffusion tensor imaging, we compared two groups of one-month-abstinent treatment-seekers, who were classified based on their drinking status between six and nine months after treatment initiation. We hypothesized that subsequent relapsers had greater white matter microstructural deficits in specific brain regions than long-term abstainers. At one month of abstinence, 37 future relapsers versus 25 future abstainers had lower fractional anisotropy (a measure of axonal organization and membrane integrity) in the corpus callosum and right stria terminalis/fornix, higher diffusivity in the genu of the corpus callosum, left and right stria terminalis/fornix, and lower diffusivity in left anterior corona radiata. These differences existed despite similar lifetime and recent drinking and smoking histories in the groups. Longer smoking duration in relapsers was associated with lower fractional anisotropy in right stria terminalis/fornix. The study identified specific microstructural biomarkers of alcohol relapse risk in adults, contributing to the definition of a neurobiological relapse risk profile in alcohol use disorder.
      Cover page: White matter microstructural correlates of relapse in alcohol dependence
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2017)

      Background

      We previously reported widespread microstructural deficits of brain white matter in alcohol-dependent individuals (ALC) compared to light drinkers in a small 1.5T diffusion tensor imaging study employing tract-based spatial statistics. Using a larger dataset acquired at 4T, the present study is an extension that investigated the effects of alcohol consumption, abstinence from alcohol, and comorbid cigarette smoking on white matter microstructure.

      Methods

      Tract-based spatial statistics were performed on 20 1-week-abstinent ALC, 52 1-month-abstinent ALC, and 30 controls. Regional measures of fractional anisotropy (FA) and mean diffusivity (MD) in the significant clusters were compared by Analysis of Covariance. The metrics were correlated with substance use history and behavioral measures.

      Results

      1-week-abstinent ALC showed lower FA than controls in the corpus callosum, right cingulum, external capsule, and hippocampus. At 1 month of abstinence, only the FA in the body of the corpus callosum of ALC remained significantly different from controls. Some regional FA deficits correlated with more severe measures of drinking and smoking histories but only weakly with mood and impulsivity measures.

      Conclusion

      White matter microstructure is abnormal during early abstinence in alcohol dependent treatment seekers and recovers into the normal range within about four weeks. The compromised white matter was related to substance use severity, mood, and impulsivity. Our findings suggest that ALC may benefit from interventions that facilitate normalization of DTI metrics to maintain abstinence, via smoking cessation, cognitive-based therapy, and perhaps pharmacology to support remyelination.
        Cover page: Effects of abstinence and chronic cigarette smoking on white matter microstructure in alcohol dependence: Diffusion tensor imaging at 4T
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