ICA-based denoising for ASL perfusion imaging.

Arterial Spin Labelling (ASL) imaging derives a perfusion image by tracing the accumulation of magnetically labeled blood water in the brain. As the image generated has an intrinsically low signal to noise ratio (SNR), multiple measurements are routinely acquired and averaged, at a penalty of increased scan duration and opportunity for motion artefact. However, this strategy alone might be ineffective in clinical settings where the time available for acquisition is limited and patient motion are increased. This study investigates the use of an Independent Component Analysis (ICA) approach for denoising ASL data, and its potential for automation. 72 ASL datasets (pseudo-continuous ASL; 5 different post-labeling delays: 400, 800, 1200, 1600, 2000 m s; total volumes = 60) were collected from thirty consecutive acute stroke patients. The effects of ICA-based denoising (manual and automated) where compared to two different denoising approaches, aCompCor, a Principal Component-based method, and Enhancement of Automated Blood Flow Estimates (ENABLE), an algorithm based on the removal of corrupted volumes. Multiple metrics were used to assess the changes in the quality of the data following denoising, including changes in cerebral blood flow (CBF) and arterial transit time (ATT), SNR, and repeatability. Additionally, the relationship between SNR and number of repetitions acquired was estimated before and after denoising the data. The use of an ICA-based denoising approach resulted in significantly higher mean CBF and ATT values (p < 0.001), lower CBF and ATT variance (p < 0.001), increased SNR (p < 0.001), and improved repeatability (p < 0.05) when compared to the raw data. The performance of manual and automated ICA-based denoising was comparable. These results went beyond the effects of aCompCor or ENABLE. Following ICA-based denoising, the SNR was higher using only 50% of the ASL-dataset collected than when using the whole raw data. The results show that ICA can be used to separate signal from noise in ASL data, improving the quality of the data collected. In fact, this study suggests that the acquisition time could be reduced by 50% without penalty to data quality, something that merits further study. Independent component classification and regression can be carried out either manually, following simple criteria, or automatically.

Episodes of flushing, dyspnea and hypertension after carotid stenting for severe carotid stenosis.

INTRODUCTION: Carotid angioplasty and stenting (CAS) is a treatment option for carotid stenosis in high surgical risk patients. As it implies instrumentation of the carotid bulb, baroreceptors dysfunction may be provoked with consequent hemodynamic instability. REPORT: An 83-year-old woman treated by CAS presented with episodes of flushing, dyspnea and palpitations accompanied by transitory desaturation, hypertension, agitation and anxiety. Symptoms started 12h after the procedure. Each episode lasted 10 min. Five episodes in 3 days were observed. DISCUSSION: A dysfunction of the carotid baroreceptors and chemoreceptors was hypothesized.

Negative emotions in migraineurs dreams: the increased prevalence of oneiric fear and anguish, unrelated to mood disorders.

BACKGROUND: Migraineurs brain has shown some functional peculiarities that reflect not only in phonophobia, and photophobia, but also in mood and sleep. Dreaming is a universal mental state characterized by hallucinatory features in which imagery, emotion, motor skills, and memory are created de novo. We evaluated dream contents and associated emotions in migraineurs. MATERIALS AND METHODS: 412 subjects: 219 controls; and 148 migraineurs (66 with aura, MA; 82 without aura, MO), and 45 tension type headache patients (TTH). A semistructured retrospective self-reported questionnaire was used to evaluate dreams. The Generalized Anxiety Disorder Questionnaire (GAD-7), and the Patient Health Questionnaire (PHQ-9) were administered to evaluate anxiety and depression. RESULTS: Migraineurs showed increased levels of anxiety (P = 0.0002 for MA versus controls, P = 0.004 for MO versus controls). Fear and anguish during dreaming were more frequently reported by migraine patients compared to controls, independently by anxiety and depression scores. DISCUSSION: The brain of migraineurs seems to dream with some peculiar features, all with a negative connotation, as fear and anguish. It may be due to the recorded negative sensations induced by recurrent migraine pain, but it may just reflect a peculiar attitude of the mesolimbic structures of migraineurs brain, activated in both dreaming and migraine attacks.

Central sensitization in photophobic and non-photophobic migraineurs: possible role of retino nuclear way in the central sensitization process.

The aim of the present study was to investigate the possible relationships between the presence of headache-related photophobia and migraine-associated allodynia--a hallmark of central sensitization--among patients with different migraine types. A sample of 456 migraineurs was studied. Our results showed that photophobia was present in a high proportion of patients, with similar figures in patients with episodic migraine or CM, and confirmed that the prevalence of allodynia was higher among CM patients than in those with episodic migraine. We found a clear association between migraine-related allodynia and photophobia only in CM patients. Overall, these findings suggest that light stimulation may contribute to central sensitization of pain pathways in migraineurs, possibly contributing to progression into chronic forms. The possible connections underlying this type of sensitization is offered by the recently published data on a non-image-forming visual retino-thalamo-cortical pathway which may allow photic signals to converge on a thalamic region which is selectively activated during migraine headache.