Brain Perfusion

Chapter 7. Concluding remarks and future research directions
The goal of this thesis was to show that brain perfusion SPECT can help to clarify important issues regarding the prodromal MCI stage of AD and relapsing NMO. Specifically, this thesis shows:

1. That based on recently published literature, brain perfusion SPECT is a valid biomarker of neuronal injury in MCI due to AD in both clinical and research settings, equivalent to FDG-PET but less expensive and more accessible worldwide (Chapter 2).

2. That brain perfusion SPECT combined with graph theoretical analysis can reveals subtle (early) CVR alterations in MCI don’t detected by the current standard analysis (Chapter 3). The revealed alterations involve brain regions directly related
That graph theoretical analysis of brain perfusion SPECT data is a promising approach to develop a CBF connectivity-based biomarker at the individual level in MCI (Chapter 4). The main advantage of connectivity-based biomarkers is that they can capture important features of the complex network that it is the brain, which is the basis of cognition and other brain functions. Moreover, as compared with other neuroimaging modalities, brain perfusion SPECT maybe offer a more practical way in clinical settings since it is frequently already part of the clinical evaluation of MCI patients as a biomarker of neuronal injury in MCI due to AD, and it is a low cost and worldwide accessible technology as concluded in Chapter 2.

4. That voxel-based analyses of brain perfusion SPECT and structural MRI data identify changes in brain perfusion and structure behind the ON attack-related process in relapsing NMO (Chapter 5), which could be relevant for the comprehension of incremental visual disability in this disease. Furthermore, these findings provide evidence that brain microvasculature is an early disease target and suggests that brain perfusion alteration could be important in the development of brain structural abnormalities in relapsing