Impact of aerobic exercise on clinical and magnetic resonance imaging biomarkers in persons with multiple sclerosis: An exploratory randomized controlled trial.

BACKGROUND: There is insufficient knowledge about how aerobic exercise impacts the disease process of multiple sclerosis, which is characterized by accumulation of white matter lesions and accelerated brain atrophy. OBJECTIVE: To examine the effect of aerobic exercise on neuroinflammation and neurodegeneration by magnetic resonance imaging and clinical measures of disease activity and progression in persons with multiple sclerosis. PATIENTS AND METHODS: An exploratory 12-week randomized control trial including an intervention group (n = 14, 12 weeks of aerobic exercise twice weekly) and a control group (n = 14, continuation of usual lifestyle). Primary outcomes were magnetic resonance imaging measures (lesion load, brain structure volume change), while secondary outcomes included disability measures, blood cytokine levels, cognitive tests and patient-reported outcomes. RESULTS: The effects of aerobic exercise on whole brain and grey matter atrophy were minor. Surprisingly, the observed effect on volume (atrophy) in selected brain substructures was heterogeneous. Putaminal and posterior cingulate volumes decreased, parahippocampal gyrus volume increased, thalamus and amygdala volume remained the same, and active lesion load and count decreased. However, apart from weak improvements in walking speed and brain-derived neurotrophic factor levels, there was no effect of aerobic exercise on other clinical, cognitive or patient-reported outcomes. CONCLUSION: These results suggest that aerobic exercise in persons with multiple sclerosis has a positive effect on the volume of some of the substructures of the brain, possibly indicating a slowing of the neurodegenerative process in these regions, but a negative impact on the volume of some other substructures, with unclear implications. Further research is needed to determine whether the slight decrease in active lesion volume and count implies an anti-inflammatory effect of aerobic exercise, and the exact significance of the heterogeneous results of volumetric assessments.

A Novel Public MR Image Dataset of Multiple Sclerosis Patients With Lesion Segmentations Based on Multi-rater Consensus.

Quantified volume and count of white-matter lesions based on magnetic resonance (MR) images are important biomarkers in several neurodegenerative diseases. For a routine extraction of these biomarkers an accurate and reliable automated lesion segmentation is required. To objectively and reliably determine a standard automated method, however, creation of standard validation datasets is of extremely high importance. Ideally, these datasets should be publicly available in conjunction with standardized evaluation methodology to enable objective validation of novel and existing methods. For validation purposes, we present a novel MR dataset of 30 multiple sclerosis patients and a novel protocol for creating reference white-matter lesion segmentations based on multi-rater consensus. On these datasets three expert raters individually segmented white-matter lesions, using in-house developed semi-automated lesion contouring tools. Later, the raters revised the segmentations in several joint sessions to reach a consensus on segmentation of lesions. To evaluate the variability, and as quality assurance, the protocol was executed twice on the same MR images, with a six months break. The obtained intra-consensus variability was substantially lower compared to the intra- and inter-rater variabilities, showing improved reliability of lesion segmentation by the proposed protocol. Hence, the obtained reference segmentations may represent a more precise target to evaluate, compare against and also train, the automatic segmentations. To encourage further use and research we will publicly disseminate on our website http://lit.fe.uni-lj.si/tools the tools used to create lesion segmentations, the original and preprocessed MR image datasets and the consensus lesion segmentations.

Sleep magnetic resonance imaging with electroencephalogram in obstructive sleep apnea syndrome.

OBJECTIVE: To evaluate the mechanism and level of upper airway obstruction in obstructive sleep apnea (OSA) patients during natural sleep, together with synchronous electroencephalogram and respiratory events registration at 3-Tesla magnetic resonance imaging (MRI) platform with high spatial and temporal resolution. STUDY DESIGN: A prospective cohort study of 20 randomly selected OSA patients. METHODS: Fifteen of 20 patients were able to complete spontaneous sleep during MRI. While asleep, dynamic MR images of pharynx were obtained in the midline sagittal view. During the scan, nasal and oral airflow, thoracoabdominal wall effort, and electroencephalogram were synchronously recorded. The physiologic data were retrospectively scored to identify periods of apneas and synchronized with dynamic MR images. RESULTS: In all 15 patients, the site of complete airway obstruction occurred at the retropalatal space. We noticed different positions of the soft palate during apneic events. In seven of 15 patients (47%), the soft palate was attached to the tongue base and moved backward, compressing the airway. In five of 15 patients (33%), the soft palate was detached from the tongue base and solely moved backward, compressing the airway. In three patients (20%), we recorded both mechanisms of complete airway obstruction. In cases with attached soft palate to the tongue base, we noticed significant narrowing of the retrolingual space during apneic events. CONCLUSION: We describe a novel mechanism of obstruction dependent on the position of soft palate. This mechanism might play an important role in selecting candidates for surgery or treatment with hypoglossal nerve stimulation. LEVEL OF EVIDENCE: 2b.

CT comparison of primary snoring and obstructive sleep apnea syndrome: role of pharyngeal narrowing ratio and soft palate-tongue contact in awake patient.

Soft palate-tongue contact and automatically calculated pharyngeal narrowing ratio (PNR), defined as a ratio between the airway cross-section at the hard palate level and the narrowest cross-section from the hard palate to the epiglottis, could assist in earlier identification of potential obstructive sleep apnea syndrome (OSA) patients even on awake individuals. Parameters were studied on carotid CTA images from 67 consecutively included awake Caucasians who were later classified by second independent physician into the primary snorers (SNORE, n = 34) or obstructive sleep apnea syndrome patient (OSA, n = 33) group according to the clinical examination, laboratory testing and a full-night video polysomnography (PSG) in the sleep laboratory. Imaging and clinical data were statistically compared between groups. The odd's ratio calculation showed a 2.95 (P = 0.0354) higher risk for OSA development in snoring person with a PNR greater than 8.6. The loose-contact subgroup among OSA patients showed significantly (P = 0.002) higher values of AHI in contrast to the in-contact subgroup.