Delayed-onset dementia after stroke or transient ischemic attack.

INTRODUCTION: Patients surviving stroke without immediate dementia are at high risk of delayed-onset dementia. Mechanisms underlying delayed-onset dementia are complex and may involve vascular and/or neurodegenerative diseases. METHODS: Dementia-free patients with stroke and/or transient ischemic attack (TIA; n = 919) were studied for 3 years prospectively, excluding those who developed dementia 3 to 6 months after stroke and/or TIA. RESULTS: Forty subjects (4.4%) developed dementia during the study period. Imaging markers of severe small vessel disease (SVD), namely presence of ≥3 lacunes and confluent white matter changes; history of hypertension and diabetes mellitus independently predicted delayed-onset dementia after adjustment for age, gender, and education. Only 6 of 31 (19.4%) subjects with delayed cognitive decline harbored Alzheimer's disease-like Pittsburg compound B (PiB) retention. Most PiB cases (16/25, 64%) had evidence of severe SVD. DISCUSSION: Severe SVD contributes importantly to delayed-onset dementia after stroke and/or TIA. Future clinical trials aiming to prevent delayed-onset dementia after stroke and/or TIA should target this high-risk group.

Influence of Amyloid-ß on Cognitive Decline After Stroke/Transient Ischemic Attack: Three-Year Longitudinal Study.

BACKGROUND AND PURPOSE: We hypothesized that comorbid amyloid-beta (Aß) deposition played a key role in long-term cognitive decline in subjects with stroke/transient ischemic attack. METHODS: We recruited 72 subjects with cognitive impairment after stroke/transient ischemic attack to receive Carbon-11-labeled Pittsburgh compound B positron emission tomography. We excluded subjects with known clinical Alzheimer's disease. Those with and without Alzheimer's disease-like Aß deposition were classified as mixed vascular cognitive impairment (mVCI, n=14) and pure VCI (pVCI, n=58), respectively. We performed Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment to evaluate global cognition and cognitive domains (memory, visuospatial function, language, attention, and executive function) at 3 to 6 months (baseline) and annually for 3 years after the index event. We compared cognitive changes between mVCI and pVCI using linear mixed models and analysis of covariance adjusted for age and education. RESULTS: Over 3 years, there were significant differences between mVCI and pVCI on change of MMSE score over time (group×time interaction, P=0.007). We observed a significant decline on MMSE score (P=0.020) in the mVCI group but not in the pVCI group (P=0.208). The annual rates of decline on MMSE (P=0.023) and Montreal Cognitive Assessment score (P=0.003) were greater in the mVCI group than in the pVCI group. Memory, visuospatial, and executive function domain scores on the Montreal Cognitive Assessment were related to Aß deposition. CONCLUSIONS: Compared with subjects without Alzheimer's disease-like Aß deposition, those with Aß deposition experienced a more severe and rapid cognitive decline over 3 years after stroke/transient ischemic attack. Aß was associated with changes in multiple cognitive domains.

Risk factors for incident dementia after stroke and transient ischemic attack.

BACKGROUND: We hypothesized that chronic brain changes are important substrates for incident dementia after stroke and transient ischemic attack (TIA). METHODS: We compared clinical and imaging features between patients with consecutive stroke/TIA with (n = 88) and without (n = 925) incident dementia at 3 to 6 months after a stroke/TIA. Pittsburg compound B (PiB) positron emission tomography was performed in 50 patients, including those with (n = 37) and without (n = 13) incident dementia. RESULTS: Age, history of diabetes mellitus, severity of white matter changes (WMCs), and medial temporal lobe atrophy (MTLA) were associated with incident dementia. Alzheimer's disease (AD)--like PiB retention was found in 29.7% and 7.7% (P = .032) of patients with and without incident dementia, respectively. CONCLUSIONS: Chronic brain changes including WMCs, MTLA, and AD pathology are associated with incident dementia after stroke/TIA. Interventions targeting these chronic brain changes may reduce burden of vascular cognitive impairment.

Subcentimetre thyroid nodules: Sonographic features associated with malignancy.

INTRODUCTION: The aim of this study was to identify the ultrasound features which are associated with malignancy in subcentimetre thyroid nodules. METHODS: This retrospective study included 454 thyroid nodules <10 mm in size in 413 patients from 2012 to 2016, which were subjected to fine needle aspiration cytology. Each nodule was classified according to the ultrasound patterns of the 2015 American Thyroid Association guidelines and the high suspicion ultrasound features (solid, hypo-echogenicity, irregular margins, microcalcifications, taller-than-wide, interrupted rim calcifications, and extrathyroidal extension) were identified for evaluation of their diagnostic performance. RESULTS: Of the American Thyroid Association high suspicion ultrasound features, univariate analysis showed that hypo-echogenicity (sensitivity 81.6% (95% CI 65.7-92.3%), specificity 50.0% (95% CI 43.4-56.6%)), irregular margins (sensitivity 34.2% (95% CI 19.6-51.4%), specificity 92.2% (95% CI 88.0-95.3%)), microcalcifications (sensitivity 23.7% (95% CI 11.4-40.2%), specificity 91.0% (95% CI 86.5-94.3%)), and taller-than-wide (sensitivity 23.7% (95% CI 11.4-40.2%), specificity 92.2% (95% CI 88.0-95.3%)) were significantly associated with a malignant diagnosis. Amongst the above features, subsequent multivariate analysis identified a combination of hypo-echogenicity and irregular margins as significantly associated with malignancy. Our malignancy rates based on American Thyroid Association ultrasound patterns from benign to high suspicion were 0.0, 8.3, 3.9, 15.7, and 40.4%, respectively. The American Thyroid Association high suspicion ultrasound pattern had a sensitivity of 50.0% (95% CI 33.4-66.7%) and specificity of 84.5% (95% CI 79.2-88.9%). CONCLUSION: The presence of both hypo-echogenicity and irregular margins was significantly associated with malignancy in subcentimetre thyroid nodules in our study. Hence, subcentimetre nodules which are hypoechoic with irregular margins may warrant further follow-up.