Susceptibility Contrast Magnetic Resonance Imaging Research Articles

NG-nitro-L-arginine methyl ester modifies the input function measured by dynamic susceptibility contrast magnetic resonance imaging.

In rat brain dynamic susceptibility contrast magnetic resonance (MR) images, vessels visible on the same scan plane as the brain tissue were used to measure the characteristics of the input function of the MR contrast agent gadopentetate dimeglumine. MR images were acquired 30 and 60 minutes after intravenous injections of 3 mg/kg and 15 mg/kg NG-Nitro-L-arginine methyl ester (L-NAME) (n = 9). The time of arrival (TOA) and the mean transit time corrected for TOA of the input function were increased by 3 mg/kg or 15 mg/kg L-NAME. The area of the input function was increased by 15 mg/kg L-NAME. In two animals, similar modifications of the input function induced by 20 mg/kg L-NAME were reversed by infusion of sodium nitroprusside. In two other animals, MABP was increased by phenylephrine to a similar extent as in L-NAME experiments, but did not induce the same modifications of the input function, showing that the action of L-NAME on the input function was not simply caused by an effect on MABP. These results show that the input function can be significantly altered by manipulations widely used in cerebrovascular studies. These input function changes have important implications for calculation of cerebral blood flow.

Applications of Dynamic Susceptibility Contrast Magnetic Resonance Imaging in Neuropsychiatry

Functional neuroimaging has assumed an important role in the cognitive and clinical neurosciences. Recently, substantial progress has been made toward developing functional magnetic resonance imaging techniques for the examination of cerebral hemodynamic changes that accompany brain function and toward earlier and better diagnosis of brain disease. Dynamic susceptibility contrast (DSC) MRI offers unique information about cerebral hemodynamics both at rest and in response to brain activation. We review the clinical applications of DSC MRI and present our experience with this modality in the evaluation of patients with neuropsychiatric disorders. Our experience suggests that DSC MRI may afford new insights into the diagnosis and treatment of cognitive disorders.

Dynamic susceptibility contrast MRI of regional cerebral blood volume in Alzheimer's disease

The purpose of this study was to investigate the potential effectiveness of dynamic susceptibility contrast magnetic resonance imaging (MRI) to discriminate elderly patients with Alzheimer's disease from normal matched comparison subjects. Images of regional cerebral blood volume (CBV) were generated from echo-planar MRI with the dynamic susceptibility contrast method in 13 Alzheimer's disease patients and 13 comparison subjects group-matched on age and gender. Temporoparietal cerebral blood volume, expressed as a percentage of the cerebellum value, was reduced 17% bilaterally in the patients with Alzheimer's disease. Blood volume in sensorimotor regions was reduced only 8.5% in the patients. Discriminant function analysis based on left and right temporoparietal measures correctly classified 88.5% of the subjects as patients or comparison subjects. Temporoparietal CBV was reduced even in mildly affected Alzheimer's disease patients (Mini-Mental State scores > 24). Dynamic susceptibility contrast MRI of regional CBV is promising as a nonradioactive, potentially lower-cost alternative to other functional neuroimaging methods for evaluating Alzheimer's disease.

Abnormalities of regional distribution of cerebral vasculature in schizophrenia detected by dynamic susceptibility contrast MRI.

The authors tested the hypothesis that the regional distribution of cerebral vasculature is anomalous in schizophrenia. Dynamic susceptibility contrast magnetic resonance imaging was used to evaluate cerebral blood volume in the right and left occipital cortex, basal ganglia, and cerebellum of 10 subjects with schizophrenia and 10 healthy comparison subjects. Cerebral blood volume was greater in the schizophrenic subjects in every region studied. The findings suggest an abnormality of the configuration of cerebral blood vessels in schizophrenia.