Irigoyen, J. (Jaione)
- Publications
- item.page.relationships.isContributorAdvisorOfPublication
- item.page.relationships.isContributorOfPublication
2 results
Search Results
Now showing 1 - 2 of 2
- Cortical hypoperfusion in Parkinson's disease assessed using arterial spin labeled perfusion MRI(Academic Press Inc Elsevier Science, 2012-02-01) Vidorreta, M. (Marta); Loayza, F.R. (Francis R.); Aznárez-Sanado, M. (Maite); Fernández-Seara, M.A. (María A.); Villagra, F. (Federico); Pastor, M.A. (María A.); Mengual, E. (Elisa); Irigoyen, J. (Jaione)Alterations in cerebral perfusion and metabolism in Parkinson's disease have been assessed in several studies, using nuclear imaging techniques and more recently magnetic resonance imaging. However, to date there is no consensus in the literature regarding the extent and the magnitude of these alterations. In this work, arterial spin labeled perfusion MRI was employed to quantify absolute cerebral blood flow in a group of earlyto- moderate Parkinson's disease patients and age-matched healthy controls. Perfusion comparisons between the two groups showed that Parkinson's disease is characterized by wide-spread cortical hypoperfusion. Subcortically, hypoperfusion was also found in the caudate nucleus. This pattern of hypoperfusion could be related to cognitive dysfunctions that have been previously observed even at the disease early stages. The present results were obtained by means of whole brain voxel-wise comparisons of absolute perfusion values, using statistical parametric mapping, thus avoiding the potentially biased global mean normalization procedure. In addition, this work demonstrates that between-group comparison of relative perfusion values after global mean normalization, introduced artifactual relative perfusion increases, where absolute perfusion was in fact preserved. This has implications for perfusion studies of other brain disorders.
- Effects on resting cerebral blood flow and functional connectivity induced by metoclopramide: a perfusion MRI study in healthy volunteers(Wiley-Blackwell, 2010-12-22) Heukamp, F. (F.); Aznárez-Sanado, M. (Maite); Fernández-Seara, M.A. (María A.); Pastor, M.A. (María A.); Mengual, E. (Elisa); Irigoyen, J. (Jaione)Background and purpose: The substituted benzamide, metoclopramide, is a dopamine receptor anatagonist and is widely prescribed in the symptomatic treatment of nausea and vomiting, although it can cause adverse motor and non-motor side effects. The effects of metoclopramide on brain metabolism have not been investigated to date. Experimental approach: To determine effects of metaclopramide on brain function, cerebral perfusion changes after a single oral dose were assessed in healthy volunteers using magnetic resonance imaging (MRI) techniques. Arterial spin labeling (ASL) perfusion MRI was used to measure cerebral blood flow before and after metoclopramide. Blood haemodynamics in the vertebral and internal carotid arteries were evaluated using phase-contrast MRI. Key results: Metoclopramide altered haemodynamics in the carotid arteries and the cerebral perfusion. Perfusion increased bilaterally in the putamen, consistent with antagonism of dopamine D(2) receptors by metoclopramide and possibly related to its motor side-effects. In contrast, reduced perfusion was observed in the insular cortices and anterior temporal lobes. In addition, functional connectivity between the insular cortex and the dorsolateral prefrontal cortex was decreased. Conclusions and implications: These cortical changes affecting neural circuits between high-order association areas may underlie certain neuropsychiatric conditions occasionally reported after metoclopramide administration. The present results show the sensitivity of ASL to detect small changes in regional blood flow, closely related to brain function, after a single pharmacological challenge, highlighting the potential of this technique for human pharmacological studies.