Conclusions and future directions
The aim of the present thesis was to show that brain perfusion SPECT can help to clarify important questions of complex neurological diseases such as the prodromal MCI stage of AD and relapsing NMO.
In chapter 2, it was showed that despite the common notion that FDG-PET performs better than brain perfusion SPECT for prediction of AD dementia in MCI, current evidence and guidelines support the clinical utilization of brain perfusion SPECT as a valid - less costly and more accessible - alternative to FDG PET.
The major disadvantage of brain perfusion SPECT is its lower spatial resolution. This disadvantage, however, seems to be coming to the end. In 2015, a new SPECT system (G-SPECT) was presented at the …show more content…
The study showed that normal cognition and MCI show different patterns of topological ACZ-induced changes, especially at the global level, while the standard approach did not detect substantial differences. The observed regional differences included the medial prefrontal cortices and inferior parietal lobe, which represent areas involved in MCI's cognitive dysfunction. Thus, our findings support the concept that multivariate measures (i.e. co-variations) combined with a graph theoretical analysis are more sensitive to identify complex pathological processes, as has found in other brain diseases (Bassett et al., 2012; He et al., 2009b). Univariate measures derived from the standard approach could be insufficient for capturing subtle (early) abnormal changes. Furthermore, these findings could have implications for early diagnosis and treatment of AD. Early CVR abnormalities, especially at the microvascular level, affect the neurovascular coupling and consequently the neural activation (Pillai and Mikulis, 2015), which in turn alters the brain's functional integrity (Iadecola, …show more content…
the use of Pearson's correlation instead of partial correlation; choice of parcellation scheme; possible variability of results with different sample sizes) (Melie-García et al.,2013). In addition, a recent study showed that the inclusion of global CBF as a confounding variable introduces artificial negative correlations in networks using resting state fMRI data (Carbonell et al., 2014), which might also be present in correlation networks using CBF SPECT. Nevertheless, all of these limitations are attenuated to some extent by studying the CBFcorr network in two different conditions, i.e. by analyzing the vasodilatory effect of ACZ after subtracting the effect of baseline. The vasodilatory effect of ACZ could be considered comparatively greater than the effects of the above methodological
The aim of the present thesis was to show that brain perfusion SPECT can help to clarify important questions of complex neurological diseases such as the prodromal MCI stage of AD and relapsing NMO.
In chapter 2, it was showed that despite the common notion that FDG-PET performs better than brain perfusion SPECT for prediction of AD dementia in MCI, current evidence and guidelines support the clinical utilization of brain perfusion SPECT as a valid - less costly and more accessible - alternative to FDG PET.
The major disadvantage of brain perfusion SPECT is its lower spatial resolution. This disadvantage, however, seems to be coming to the end. In 2015, a new SPECT system (G-SPECT) was presented at the …show more content…
The study showed that normal cognition and MCI show different patterns of topological ACZ-induced changes, especially at the global level, while the standard approach did not detect substantial differences. The observed regional differences included the medial prefrontal cortices and inferior parietal lobe, which represent areas involved in MCI's cognitive dysfunction. Thus, our findings support the concept that multivariate measures (i.e. co-variations) combined with a graph theoretical analysis are more sensitive to identify complex pathological processes, as has found in other brain diseases (Bassett et al., 2012; He et al., 2009b). Univariate measures derived from the standard approach could be insufficient for capturing subtle (early) abnormal changes. Furthermore, these findings could have implications for early diagnosis and treatment of AD. Early CVR abnormalities, especially at the microvascular level, affect the neurovascular coupling and consequently the neural activation (Pillai and Mikulis, 2015), which in turn alters the brain's functional integrity (Iadecola, …show more content…
the use of Pearson's correlation instead of partial correlation; choice of parcellation scheme; possible variability of results with different sample sizes) (Melie-García et al.,2013). In addition, a recent study showed that the inclusion of global CBF as a confounding variable introduces artificial negative correlations in networks using resting state fMRI data (Carbonell et al., 2014), which might also be present in correlation networks using CBF SPECT. Nevertheless, all of these limitations are attenuated to some extent by studying the CBFcorr network in two different conditions, i.e. by analyzing the vasodilatory effect of ACZ after subtracting the effect of baseline. The vasodilatory effect of ACZ could be considered comparatively greater than the effects of the above methodological