Prevalence and Risk Factors of Brain Infarcts and Associations With Cognitive Performance in Tenants of Marginal Housing

Background

Homeless and vulnerably housed individuals are at increased risk for multimorbidity compared with the general population. We assessed prevalence of brain infarcts on neuroimaging and associations with vascular risk factors and cognitive performance in a prospective study of residents living in marginal housing.

Methods and Results

Two hundred twenty‐eight participants underwent structured clinical interviews, targeted clinical, laboratory, and neuropsychological assessments, and magnetic resonance imaging with T₁, T₂‐fluid‐attenuated inversion recovery and susceptibility‐weighted images. Subjects underwent cognitive testing to assess premorbid IQ, verbal learning and memory, inhibition, sustained attention, mental flexibility, and decision making. In this sample (mean age 44.0 years [SD 9.4], 77% male), prevalence of conventional vascular risk factors was lower than in the general population apart from tobacco use (94%). Ten‐year Framingham risk for any cardiovascular event was 11.4%±9.2%. Brain infarcts were present in 25/228 (11%). All were ischemic (40% cortical, 56% lacunar, 4% both). Participants with infarcts were older than those without (48.9±9.4 versus 43.4±9.2, P=0.006). In a multivariable regression analysis, only age remained a significant predictor of brain infarcts (odds ratio 1.08, 95% CI1.02–1.14, P=0.004). After controlling for age and education, the presence of infarct was a significant predictor of impaired decision making on the Iowa Gambling Task of decision making (β −28.2, 95% CI −42.7 to −14.1, P<0.001).

Conclusions

Prevalence of infarcts on neuroimaging in this disadvantaged, community‐dwelling cohort was much higher than expected for age and was associated with impaired decision making. Further research is needed to identify individuals at highest risk who may benefit from targeted preventative strategies.

Hippocampal volume and vasculature before and after exercise in treatment-resistant schizophrenia

BACKGROUND

Schizophrenia is associated with poor cognitive function and elevated cardiometabolic disease risk. These health concerns may exacerbate neurocognitive dysfunction associated with hippocampal abnormalities, particularly hippocampal volume reductions. Regular exercise is thought to improve symptom severity, reduce depression, and improve cognition in schizophrenia, and may trigger exercise-mediated hippocampal growth. The potential for the benefits of exercise for treatment-resistant schizophrenia patients has not been clearly assessed. This study aims to assess the effect of exercise on hippocampal plasticity and clinical outcomes in chronic schizophrenia.

METHODS

Seventeen DSM-IV criteria schizophrenia or schizoaffective disorder patients completed a customized moderate intensity 12-week aerobic or weight-bearing exercise program. Adherence rates were 83% ± 9.4%) with 70% of participants completing the entire exercise program. Concomitant neuroimaging, clinical and cognitive assessments were obtained at baseline and 12-weeks.

RESULTS

At follow-up, symptom severity scores (t(16) = -16.8, p. ≤ 0.0001) and social functioning (t(16) = 4.4, p. = 0.0004) improved. A trend for improved depression scores (t(16) = -2.0, p. = 0.06) with no change in anxiety, or extrapyramidal symptoms were seen. Hippocampal volume increased (t(16) = -2.54, p. = 0.02), specifically in the left CA-1 field (F(16) = -2.33, p. = 0.03). Hippocampal vascular volume was unchanged. Change in hippocampal volume and vascular volume was not significantly correlated with change in symptom severity or affect scores.

CONCLUSIONS

Adjunct exercise may accelerate symptom improvement in treatment-resistant psychosis patients. While the underlying mechanism remains unclear, these results indicate that chronic schizophrenia patients experience hippocampal plasticity in response to exercise.

STUDY REGISTRATION

Clinical Trials.govNCT01392885.

White matter tract abnormalities in first-episode psychosis

Fibers connecting fronto-temporal and fronto-medial structures that pass through the anterior limb of the internal capsule (ALIC) subserve executive and psychomotor functioning. Both of these functions are adversely affected in schizophrenia, and may be abnormal at illness onset. In a study of first-episode psychosis, we used diffusion tensor imaging (DTI) and cognitive testing to examine ALIC integrity. Fourteen early psychosis patients and 29 healthy volunteers were included. Symptoms were assessed with the Positive and Negative Syndromes Scale (PANSS). All structural and diffusion scans were acquired on a GE Signa 1.5T scanner. A T1-weighted 3D FSPGR Inversion Recovery imaging series was acquired for manual seeding in structural space. Diffusion tensor imaging (DTI) was performed, and all DTI images were co-registered to structural space. Seeds were manually drawn bilaterally on the coronal plane at a specified location. Diffusion images were post-processed for subsequent Tract-based Spatial Statistics (TBSS) analysis. First-episode psychosis patients had significantly smaller fronto-medial and fronto-temporal AIC tract volumes compared to healthy volunteers on the left and the right (p-values<0.04). No differences in mean fractional anisotropy (FA) were seen within either left or right tracts (p-values>0.05), nor did TBSS reveal any other differences in FA values between groups in other regions. Relationships between tract volumes and symptom severity were not observed in this study.

Imaging in adult scoliosis: preoperative assessment and postoperative complications

Adult scoliosis rates range from 2 to 32%. Surgery for scoliosis is common. Accurate and surgically relevant information should be provided to the referring surgeon from pre- and postoperative imaging. There are various methods to correct scoliosis surgically with the end points correction of the curve and relief of symptoms. This is achieved through the placement of spinal instrumentation with a goal of osseous fusion across the instrumented levels. There are many potential postoperative complications. The initial and postoperative imaging, types of surgery, and hardware are reviewed along with the common early and late complications with relevant illustrations.

Localization of the subthalamic nucleus: optimization with susceptibility-weighted phase MR imaging

BACKGROUND AND PURPOSE

On clinical MR images, the subthalamic nuclei (STN) are poorly delineated from adjacent structures, impeding safe direct targeting for placement of electrodes in the treatment of Parkinson disease. Susceptibility-weighted MR phase imaging offers improved contrast and spatial resolution at reduced imaging times relative to clinically used T2-weighted spin-echo imaging for STN visualization. Our purpose was to assess STN visibility by using phase imaging, comparing phase and magnitude images obtained concurrently by using susceptibility-weighted imaging (SWI). The goal was to identify an efficient scanning protocol for high-quality phase images of STN.

MATERIALS AND METHODS

Seventy-eight SWI scans were acquired at 3T by using different TEs and acceleration factors. STN visibility and delimitation from adjacent structures were scored from 0 (not interpretable) to 5 (excellent). Regression analyses assessed the relationship of STN visibility to scanning parameters

RESULTS

STN were identified at all studied TEs on phase images. Visibility and delimitation of STN were consistently superior on phase images compared with magnitude images. Good visualization (score of >or=4) of STN on phase imaging occurred at a mean TE of 20.0 ms and a sensitivity encoding (SENSE) of 1.40. Scores of STN visualization on phase images were dependent on SENSE (P < .002) and TE (P < .031). Good delimitation of the STN on phase imaging occurred at a mean TE of 21.6 ms and a SENSE of 1.36.

CONCLUSIONS

Visualization and delimitation of STN was superior on phase images and was achieved at 3T in <2.5 minutes. A TE of 20 ms and an acceleration factor of <or=1.5 are recommended to visualize STN by using this method.

Comparison of multidetector CT angiography and MR imaging of cervical artery dissection

BACKGROUND AND PURPOSE

Conventional angiography has been historically considered the gold standard for the diagnosis of cervical artery dissection, but MR imaging/MR angiography (MRA) and CT/CT angiography (CTA) are commonly used noninvasive alternatives. The goal of this study was to compare the ability of multidetector CT/CTA and MR imaging/MRA to detect common imaging findings of dissection.

MATERIALS AND METHODS

Patients in the data base of our Stroke Center between 2003 and 2007 with dissections who had CT/CTA and MR imaging/MRA on initial work-up were reviewed retrospectively. Two neuroradiologists evaluated the images for associated findings of dissection, including acute ischemic stroke, luminal narrowing, vessel irregularity, wall thickening/hematoma, pseudoaneurysm, and intimal flap. The readers also subjectively rated each vessel on the basis of whether the imaging findings were more clearly displayed with CT/CTA or MR imaging/MRA or were equally apparent.

RESULTS

Eighteen patients with 25 dissected vessels (15 internal carotid arteries [ICA] and 10 vertebral arteries [VA]) met the inclusion criteria. CT/CTA identified more intimal flaps, pseudoaneurysms, and high-grade stenoses than MR imaging/MRA. CT/CTA was preferred for diagnosis in 13 vessels (5 ICA, 8 VA), whereas MR imaging/MRA was preferred in 1 vessel (ICA). The 2 techniques were deemed equal in the remaining 11 vessels (9 ICA, 2 VA). A significant preference for CT/CTA was noted for VA dissections (P < .05), but not for ICA dissections.

CONCLUSION

Multidetector CT/CTA visualized more features of cervical artery dissection than MR imaging/MRA. CT/CTA was subjectively favored for vertebral dissection, whereas there was no technique preference for ICA dissection. In many cases, MR imaging/MRA provided complementary or confirmatory information, particularly given its better depiction of ischemic complications.