Three‐dimensional MRI perfusion maps: a step beyond volumetric analysis in mental disorders

Abstract

A new type of magnetic resonance imaging analysis, based on fusion of three-dimensional reconstructions of timeto-peak parametric maps and high-resolution T1-weighted images, is proposed in order to evaluate the perfusion of selected volumes of interest. Because in recent years a wealth of data have suggested the crucial involvement of vascular alterations in mental diseases, we tested our new method on a restricted sample of schizophrenic patients and matched healthy controls. The perfusion of the whole brain was compared with that of the caudate nucleus by means of intrasubject analysis. As expected, owing to the encephalic vascular pattern, a significantly lower time-to-peak was observed in the caudate nucleus than in the whole brain in all healthy controls, indicating that the suggested method has enough sensitivity to detect subtle perfusion changes even in small volumes of interest. Interestingly, a less uniform pattern was observed in the schizophrenic patients. The latter finding needs to be replicated in an adequate number of subjects. In summary, the three-dimensional analysis method we propose has been shown to be a feasible tool for revealing subtle vascular changes both in normal subjects and in pathological conditions.

Correlation and Characteristics of Intravoxel Incoherent Motion and Arterial Spin Labeling Techniques Versus Multiple Parameters Obtained on Dynamic Susceptibility Contrast Perfusion MRI for Brain Tumors

“…Using the numeric integration of cerebral blood flow values, DSC-rBF maps were created (7,10). The time to peak (TTP) was calculated on DSC MRI and is the time from the injection of the contrast medium to the peak of the signal increase ; it reaches its highest concentration in specific areas of interest (22). The leakage or permeability rate, which is useful for DSC tumor imaging, is described by the K2 (11).…”

Increased hippocampal blood volume and normal blood flow in schizophrenia

“…Since the review, there have been two additional studies of bolus-tracking perfusion imaging with a paramagnetic agent in schizophrenia (Bellani et al, 2011; Peruzzo et al, 2011). Together, these studies illustrate several findings in schizophrenia: low and inverse hemispheric CBV as indirectly measured through contrast enhancement (CE) (Brambilla et al, 2007); increased CBV in the cerebellum (Loeber et al, 1999), caudate, and occipital cortex (Cohen et al, 1995); no alterations in CBV, CBF, or MTT in the cerebrum or cerebellum (Bellani et al, 2011); decreased frontal cortex CBV and CBF only when using a best predictor model containing clinical state, age, and length of illness (Peruzzo et al, 2011); variable time-to-peak (TTP) in the caudate (Fabene et al, 2007); and increased perfusion in the prefrontal cortex, temporal lobe, and posterior parietal cortices after dopamine receptor D1 agonist administration (Mu et al, 2007). Importantly, none of these studies used a region of interest-based analysis to report hemodynamic properties in the hippocampus in schizophrenia, even though functional abnormalities have been reported in this medial temporal lobe structure.…”