Contribution of normal aging to brain atrophy in MS.

OBJECTIVE: To identify the top brain regions affected by MS-specific atrophy (i.e., atrophy in excess of normal aging) and to test whether normal aging and MS-specific atrophy increase or decrease in these regions with age. METHODS: Six hundred fifty subjects (2,790 MRI time points) were analyzed: 520 subjects with relapse-onset MS from a 5-year prospective cohort with annual standardized 1-mm 3D T1-weighted images (3DT1s; 2,483 MRIs) and 130 healthy controls with longitudinal 3DT1s (307 MRIs). Rates of change in all FreeSurfer regions (v5.3) and Structural Image Evaluation Using Normalization of Atrophy (SIENA) were estimated with mixed-effects models. All FreeSurfer regions were ranked by the MS-specific atrophy slope/standard error ratio (ßMS × time/SEßMS × time). In the top regions, age was added as an effect modifier to test whether MS-specific atrophy varied by age. RESULTS: The top-ranked regions were all gray matter structures. For SIENA, normal aging increased from 0.01%/y at age 30 years to -0.31%/y at age 60 years (-0.11% ± 0.032%/decade, p < 0.01), whereas MS-specific atrophy decreased from -0.38%/y at age 30 years to -0.12%/y at age 60 years (0.09% ± 0.035%/decade, p = 0.01). Similarly, in the thalamus, normal aging increased from -0.15%/y at age 30 years to -0.62%/y at age 60 years (-0.16% ± 0.079%/decade, p < 0.05), and MS-specific atrophy decreased from -0.59%/y at age 30 years to -0.05%/y at age 60 years (0.18% ± 0.08%/decade, p < 0.05). In the putamen and caudate, normal aging and MS-specific atrophy did not vary by age. CONCLUSIONS: For SIENA and thalamic atrophy, the contribution of normal aging increases with age, but does not change in the putamen and caudate. This may have substantial implications to understand the biology of brain atrophy in MS.

Thalamic atrophy in multiple sclerosis: A magnetic resonance imaging marker of neurodegeneration throughout disease.

OBJECTIVE: Thalamic volume is a candidate magnetic resonance imaging (MRI)-based marker associated with neurodegeneration to hasten development of neuroprotective treatments. Our objective is to describe the longitudinal evolution of thalamic atrophy in MS and normal aging, and to estimate sample sizes for study design. METHODS: Six hundred one subjects (2,632 MRI scans) were analyzed. Five hundred twenty subjects with relapse-onset MS (clinically isolated syndrome, n = 90; relapsing-remitting MS, n = 392; secondary progressive MS, n = 38) underwent annual standardized 3T MRI scans for an average of 4.1 years, including a 1mm3 3-dimensional T1-weighted sequence (3DT1; 2,485 MRI scans). Eighty-one healthy controls (HC) were scanned longitudinally on the same scanner using the same protocol (147 MRI scans). 3DT1s were processed using FreeSurfer's longitudinal pipeline after lesion inpainting. Rates of normalized thalamic volume loss in MS and HC were compared in linear mixed effects models. Simulation-based sample size calculations were performed incorporating the rate of atrophy in HC. RESULTS: Thalamic volume declined significantly faster in MS subjects compared to HC, with an estimated decline of -0.71% per year (95% confidence interval [CI] = -0.77% to -0.64%) in MS subjects and -0.28% per year (95% CI = -0.58% to 0.02%) in HC (p for difference = 0.007). The rate of decline was consistent throughout the MS disease duration and across MS clinical subtypes. Eighty or 100 subjects per arm (α = 0.1 or 0.05, respectively) would be needed to detect the maximal effect size with 80% power in a 24-month study. INTERPRETATION: Thalamic atrophy occurs early and consistently throughout MS. Preliminary sample size calculations appear feasible, adding to its appeal as an MRI marker associated with neurodegeneration. Ann Neurol 2018;83:223-234.

Preliminary Results of Lung Cancer Screening in a Socioeconomically Disadvantaged Population.

OBJECTIVE: The objective of our study was to describe the preliminary results of our clinical low-dose CT (LDCT) lung cancer screening program targeting a minority, socioeconomically disadvantaged, high-risk population different from that studied in the National Lung Screening Trial (NLST). MATERIALS AND METHODS: Community partner clinics in an underserved region of south Los Angeles County referred interested candidates to our program. All patients met National Comprehensive Cancer Network eligibility criteria for lung cancer screening. RESULTS: From July 21, 2015, through April 3, 2017, 889 individuals were referred to the program. Of the 329 eligible participants, 275 (mean age, 59 years; 52% men) underwent baseline screening LDCT: 84% of patients were black, and 66% had a high school education or less. The median pack-years was 40, and 81% of patients were current smokers. Thirty-one percent of participants reported occupational exposure to one or more known lung carcinogens. Lung CT Screening Reporting and Data System (Lung-RADS) categories were assigned using baseline LDCT examinations: Lung-RADS category 1 or 2 were assigned in 86% of patients, category 3 in 7%, category 4A in 4%, and category 4B or 4X in 3%. Lung cancer has been diagnosed in two of these patients (0.7%) to date: stage IIIB small cell lung carcinoma in one patient and stage IV lung cancer of unknown type in the other patient. Among the 275 patients, 29% had potentially clinically significant incidental findings. CONCLUSION: Lung cancer screening with LDCT in a minority, socioeconomically disadvantaged, high-risk population is feasible but may yield a different lung cancer profile than screening populations in more privileged communities. More follow-up time is required to determine whether the reduction in lung cancer mortality shown in the NLST applies to this underserved population.