scholarly journals Gender Differences in Cerebral Blood Flow and Oxygenation Response during Focal Physiologic Neural Activity

1999 ◽  
Vol 19 (10) ◽  
pp. 1066-1071 ◽  
Author(s):  
Andreas Kastrup ◽  
Tie-Qiang Li ◽  
Gary H. Glover ◽  
Gunnar Krüger ◽  
Michael E. Moseley
Keyword(s):  
Magnetic Resonance Imaging ◽  
Gender Differences ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Visual Stimulation ◽  
Imaging Techniques ◽  
Blood Oxygenation ◽  
Intensity Change ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Using functional magnetic resonance imaging techniques CBF and oxygenation changes were measured during sustained checkerboard stimulation in 38 right-handed healthy volunteers (18 men and 20 women). The average blood oxygenation level dependent (BOLD) contrast technique signal intensity change was 1.67 ± 0.6% in the group of male volunteers and 2.15 ± 0.6% in the group of female volunteers ( P < .05). Baseline regional CBF (rCBF) values in activated gray matter areas within the visual cortex were 57 ± 1 mL · 100 g−1 · min−1 in women and 50 ± 12 mL · 100 g−1 · min−1 in men, respectively ( P = .09). Despite a broad overlap between both groups the rCBF increase was significantly higher in women compared to men (33 ± 5 mL · 100 g−1 · min−1 versus 28 ± 4 mL · 100 g−1 · min−1, P < .01). The increase of rCBF was not correlated with the baseline rCBF (mL · 100 g−1 · min−1) (rs = 0.01, P = .9). Moreover, changes of rCBF were not correlated with changes in BOLD signal intensities (rs = 0.1, P = .7). Enhanced rCBF response in women during visual stimulation could be related to gender differences in visual physiology or may reflect gender differences in the vascular response to focal neuronal activation. Gender differences must be considered when interpreting the results of functional magnetic resonance imaging studies.

scholarly journals A Functional Magnetic Resonance Imaging Technique Based on Nulling Extravascular Gray Matter Signal

2008 ◽  
Vol 29 (1) ◽  
pp. 144-156 ◽  
Author(s):  
Yuji Shen ◽  
Risto A Kauppinen ◽  
Rishma Vidyasagar ◽  
Xavier Golay
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Gray Matter ◽  
Visual Stimulation ◽  
Brain Activation ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Fmri Signal

A new functional magnetic resonance imaging (fMRI) technique is proposed based on nulling the extravascular gray matter (GM) signal, using a spatially nonselective inversion pulse. The remaining MR signal provides cerebral blood volume (CBV) information from brain activation. A theoretical framework is provided to characterize the sources of GM-nulled (GMN) fMRI signal, effects of partial voluming of cerebrospinal fluid (CSF) and white matter, and behaviors of GMN fMRI signal during brain activation. Visual stimulation paradigm was used to explore the GMN fMRI signal behavior in the human brain at 3T. It is shown that the GMN fMRI signal increases by 7.2% ± 1.5%, which is two to three times more than that obtained with vascular space occupancy (VASO)-dependent fMRI (−3.2% ± 0.2%) or blood oxygenation level-dependent (BOLD) fMRI (2.9% ± 0.7%), using a TR of 3,000 ms and a resolution of 2 × 2 × 5 mm3. Under these conditions the fMRI signal-to-noise ratio (SNRfMRI) for BOLD, GMN, and VASO images was 4.97 ± 0.76, 4.56 ± 0.86, and 2.43 ± 1.06, respectively. Our study shows that both signal intensity and activation volume in GMN fMRI depend on spatial resolution because of partial voluming from CSF. It is shown that GMN fMRI is a convenient tool to assess CBV changes associated with brain activation.

scholarly journals Functional magnetic resonance imaging: imaging techniques and contrast mechanisms

1999 ◽  
Vol 354 (1387) ◽  
pp. 1179-1194 ◽  
Author(s):  
Alistair M. Howseman ◽  
Richard W. Bowtel
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
High Speed ◽  
Imaging Techniques ◽  
Brain Activity ◽  
Blood Oxygenation ◽  
Neuronal Firing ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Functional magnetic resonance imaging (fMRI) is a widely used technique for generating images or maps of human brain activity. The applications of the technique are widespread in cognitive neuroscience and it is hoped they will eventually extend into clinical practice. The activation signal measured with fMRI is predicated on indirectly measuring changes in the concentration of deoxyhaemoglobin which arise from an increase in blood oxygenation in the vicinity of neuronal firing. The exact mechanisms of this blood oxygenation level dependent (BOLD) contrast are highly complex. The signal measured is dependent on both the underlying physiological events and the imaging physics. BOLD contrast, although sensitive, is not a quantifiable measure of neuronal activity. A number of different imaging techniques and parameters can be used for fMRI, the choice of which depends on the particular requirements of each functional imaging experiment. The high–speed MRI technique, echo–planar imaging provides the basis for most fMRI experiments. The problems inherent to this method and the ways in which these may be overcome are particularly important in the move towards performing functional studies on higher field MRI systems. Future developments in techniques and hardware are also likely to enhance the measurement of brain activity using MRI.

A Quantitative Physiologic Model of Blood Oxygenation for Functional Magnetic Resonance Imaging

1995 ◽  
Vol 30 (11) ◽  
pp. 669-682 ◽  
Author(s):  
GASSER M. HATHOUT ◽  
SANJIV S. GAMBHIR ◽  
RAMESH K. GOPI ◽  
KONRAD A.T. KIRLEW ◽  
YONG CHOI ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Physiologic Model

Distinctive Cortical Articulatory Representation in Cleft Lip and Palate: A Preliminary Functional Magnetic Resonance Imaging Study

2006 ◽  
Vol 43 (5) ◽  
pp. 620-624 ◽  
Author(s):  
Hideo Shinagawa ◽  
Takashi Ono ◽  
Ei-ichi Honda ◽  
Tohru Kurabayashi ◽  
Atsushi Iriki ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Sensorimotor Cortex ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Blood Oxygenation ◽  
Cortical Representation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Objective: To investigate cortical representation of articulation of the bilabial plosive in patients with cleft lip and palate. Design: We examined cortical representation for /pa/-articulation in cleft lip and palate patients using blood oxygenation level–dependent functional magnetic resonance imaging. Subjects: Data from four postsurgical adult cleft lip and palate patients were compared with those from six healthy volunteers. Results: Activation foci were found in the bilateral primary sensorimotor cortex in all cleft lip and palate patients, as in the controls. The sensorimotor cortex ipsilateral to the side of cleft lip and palate showed greater activation in unilateral cleft lip and palate patients, whereas the sensorimotor cortex contralateral to the side on which cheiloplasty had been performed earlier showed greater activation in a bilateral cleft lip and palate patient. Conclusions: The results suggest that there may be an ipsilateral dominance in cortical representation during bilabial articulation to the side of the cleft in the upper lip.

Pediatric Functional Magnetic Resonance Imaging: Clinical Applications

2017 ◽  
Vol 16 (02) ◽  
pp. 078-093
Author(s):  
Kirk Welker ◽  
Mai-Lan Ho
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Study Design ◽  
Pediatric Population ◽  
Clinical Applications ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Design Data

AbstractTask-based functional magnetic resonance imaging (fMRI) is an imaging technique based on blood oxygenation level-dependent imaging. Maps of brain activation are generated during the performance of designated tasks involving eloquent functions, such as motor, sensory, visual, auditory, and/or language. Optimal performance of fMRI in children requires consideration of multiple psychological and physiological parameters. Also, a solid technical understanding is needed for appropriate study design, implementation, processing, and interpretation. In this article, the authors review the key principles of fMRI technique, study design, data processing, and interpretation. The important clinical applications in the pediatric population will be highlighted, accompanied by example cases from their institution.

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