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Introduction Preclinical studies support investigation of focused ultrasound for breakdown of cerebral pathologies in neurodegenerative conditions including Alzheimer's disease (AD) and Parkinson's disease (PD). Methods A focused transcranial Doppler device with probes (2 MHz, 520 mW/cm 2 ) affixed bilaterally was used to target the hippocampus (AD) or substantia nigra (PD) with functional magnetic resonance imaging navigation for enhanced plaque removal. A total of 22 patients (n = 11 AD, n = 11 PD) underwent 8 consecutive, weekly, 1-hour treatments wherein sleep was encouraged naturally or pharmacologically. Cognitive and motor functioning assessment was carried out using standardized evaluations at baseline and conclusion. Results Of all, 62.5% of patients had one or more improved cognitive scores without data incongruence, 87% had stable or improved fine motor scores, and 87.5% had stable or improved gross motor scores. No adverse events were reported. Discussion The safety of focused transcranial Doppler and possible enhancement in patient functioning were suggested by outcome data.
Background: This study sought to validate the clinical utility of multimodal magnetic resonance imaging (MRI) techniques in the assessment of neurodegenerative disorders. We intended to demonstrate that advanced neuroimaging techniques commonly used in research can effectively be employed in clinical practice to accurately differentiate heathy aging and dementia subtypes.Methods: Twenty patients with dementia of the Alzheimer's type (DAT) and 18 patients with Parkinson's disease dementia (PDD) were identified using gold-standard techniques. Twenty-three healthy, age and sex matched control participants were also recruited. All participants underwent multimodal MRI including T1 structural, diffusion tensor imaging (DTI), arterial spin labeling (ASL), and magnetic resonance spectroscopy (MRS). MRI modalities were evaluated by trained neuroimaging readers and were separately assessed using cross-validated, iterative discriminant function analyses with subsequent feature reduction techniques. In this way, each modality was evaluated for its ability to differentiate patients with dementia from healthy controls as well as to differentiate dementia subtypes.Results: Following individual and group feature reduction, each of the multimodal MRI metrics except MRS successfully differentiated healthy aging from dementia and also demonstrated distinct dementia subtypes. Using the following ten metrics, excellent separation (95.5% accuracy, 92.3% sensitivity; 100.0% specificity) was achieved between healthy aging and neurodegenerative conditions: volume of the left frontal pole, left occipital pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, right planum temporale; perfusion of the left hippocampus and left occipital lobe; fractional anisotropy (FA) of the forceps major and bilateral anterior thalamic radiation. Using volume of the left frontal pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, perfusion of the left hippocampus and left occipital lobe; FA of the forceps major and bilateral anterior thalamic radiation, neurodegenerative subtypes were accurately differentiated as well (87.8% accuracy, 95.2% sensitivity; 85.0% specificity). Conclusions: Regional volumetrics, DTI metrics, and ASL successfully differentiated dementia patients from controls with sufficient sensitivity to differentiate dementia subtypes. Similarly, feature reduction results suggest that advanced analyses can meaningfully identify brain regions with the most positive predictive value and discriminant validity. Together, these advanced neuroimaging techniques can contribute significantly to 2 Kuhn et al. Multimodal MRI in the clinic
Objective: Low-Intensity Focused Ultrasound Pulsations (LIFUP) is a promising new potential neuromodulation tool. However, the safety of LIFUP neuromodulation has not yet been adequately assessed. Patients with refractory temporal lobe epilepsy electing to undergo an anterior temporal lobe resection present a unique opportunity to evaluate the safety and efficacy of LIFUP neuromodulation. Because the brain tissue in these patients will be removed, histological changes in tissue after LIFUP can be examined. Evidence of effective neuromodulation was assessed using functional MRI and EEG, while further potential safety concerns were assessed using neuropsychological testing. Methods: EEG, functional MRI, and neuropsychology were assessed in six patients before and 2 after focused ultrasound sonication of the temporal lobe at intensities up to 5760 mW/cm . Using the BrainSonix Pulsar 1002, LIFUP was delivered under MR guidance, using the Siemens Magnetom 3T Prisma scanner. Neuropsychological changes were assessed using various batteries. EEG was recorded using the Electrical Geodesics EGI 256 channel system. Histological changes were assessed using hematoxylin and eosin staining, among others. Results: LIFUP was not able to modulate the BOLD signal on fMRI in a reliable and consistent manner. The EEG data that was available did not demonstrate a change in activity after LIFUP in all but one subject. Likewise, the neuropsychology testing did not show any statistically significant changes in any test, except for a slight decrease in performance on the one test after LIFUP. Lastly, the histology did not reveal any detectable damage to the tissue, except for one subject for whom the histology findings were inconclusive. Significance: The safety in the histology was the primary endpoint, and as such, longer exposure at the highest intensity levels will be administered moving forward.
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