Postmortem Brain Imaging in Alzheimer's Disease and Related Dementias: The South Texas Alzheimer's Disease Research Center Repository.

BACKGROUND: Neuroimaging bears the promise of providing new biomarkers that could refine the diagnosis of dementia. Still, obtaining the pathology data required to validate the relationship between neuroimaging markers and neurological changes is challenging. Existing data repositories are focused on a single pathology, are too small, or do not precisely match neuroimaging and pathology findings. OBJECTIVE: The new data repository introduced in this work, the South Texas Alzheimer's Disease research center repository, was designed to address these limitations. Our repository covers a broad diversity of dementias, spans a wide age range, and was specifically designed to draw exact correspondences between neuroimaging and pathology data. METHODS: Using four different MRI sequences, we are reaching a sample size that allows for validating multimodal neuroimaging biomarkers and studying comorbid conditions. Our imaging protocol was designed to capture markers of cerebrovascular disease and related lesions. Quantification of these lesions is currently underway with MRI-guided histopathological examination. RESULTS: A total of 139 postmortem brains (70 females) with mean age of 77.9 years were collected, with 71 brains fully analyzed. Of these, only 3% showed evidence of AD-only pathology and 76% had high prevalence of multiple pathologies contributing to clinical diagnosis. CONCLUSION: This repository has a significant (and increasing) sample size consisting of a wide range of neurodegenerative disorders and employs advanced imaging protocols and MRI-guided histopathological analysis to help disentangle the effects of comorbid disorders to refine diagnosis, prognosis and better understand neurodegenerative disorders.

Changes in Brain Volume Associated with Trauma-Focused Cognitive Behavioral Therapy Among Youth with Posttraumatic Stress Disorder.

This study investigated group differences and longitudinal changes in brain volume before and after trauma-focused cognitive behavioral therapy (TF-CBT) in 20 unmedicated youth with maltreatment-related posttraumatic stress disorder (PTSD) and 20 non-trauma-exposed healthy control (HC) participants. We collected MRI scans of brain anatomy before and after 5 months of TF-CBT or the same time interval for the HC group. FreeSurfer software was used to segment brain images into 95 cortical and subcortical volumes, which were submitted to optimal scaling regression with lasso variable selection. The resulting model of group differences at baseline included larger right medial orbital frontal and left posterior cingulate corticies and smaller right midcingulate and right precuneus corticies in the PTSD relative to the HC group, R2 = .67. The model of group differences in pre- to posttreatment change included greater longitudinal changes in right rostral middle frontal, left pars triangularis, right entorhinal, and left cuneus corticies in the PTSD relative to the HC group, R2 = .69. Within the PTSD group, pre- to posttreatment symptom improvement was modeled by longitudinal decreases in the left posterior cingulate cortex, R2 = .45, and predicted by baseline measures of a smaller right isthmus (retrosplenial) cingulate and larger left caudate, R2 = .77. In sum, treatment was associated with longitudinal changes in brain regions that support executive functioning but not those that discriminated PTSD from HC participants at baseline. Additionally, results confirm a role for the posterior/retrosplenial cingulate as a correlate of PTSD symptom improvement and predictor of treatment outcome.

Simultaneous Blood Glucose Monitoring During Gastric-Emptying Scintigraphy May Identify Unsuspected Abnormalities.

PURPOSE: A retrospective study of 197 patients was performed to evaluate utility of simultaneous fingerstick glucose monitoring during standardized solid meal gastric-emptying scintigraphy (GES). We hypothesized the unlabeled carbohydrate components of the standardized meal often empty at different rates than the labeled egg protein component and that simultaneous glucose monitoring may identify rapid carbohydrate gastric emptying. METHODS: Patients were classified as normal, rapid, or delayed gastric emptying from the standardized solid egg meal GES criteria. Further subcategorization was made based on postprandial glycemic excursions above baseline at 30/60 minutes and was delineated as elevated (>75 mg/>85 mg/dL), normal, or diminished (<30 mg/dL) glucose excursion. RESULTS: Of the 197 patients, solid gastric-emptying rates for 105 were normal, delayed in 54, and rapid in 25 patients, and 13 patients had initially delayed emptying 1 or 2 hours with normal emptying by 4 hours. Of the 105 patients with normal gastric emptying, 58 had elevated, 47 normal, and none had diminished glucose excursions. Of the 54 patients with delayed gastric emptying, 26 had elevated, 16 had normal, and 12 had diminished glucose excursions. Nine patients with normal or delayed gastric emptying but elevated glycemic excursions returned for a liquid glucose GES. In contrast to their standardized GES results, all 9 had rapid emptying with elevated glycemic excursions. CONCLUSIONS: Simultaneous blood glucose monitoring with standardized GES protocols may provide a marker for contradictory findings of rapid gastric emptying of the unlabeled carbohydrate component in the standardized meal and may contribute to unexplained postprandial gastrointestinal symptoms. The additional insights provided by fingerstick glucose monitoring are inexpensive, easy to perform and may provide for new approaches to management of patient's gastrointestinal symptoms.