Page 17 - Bladder Dysfunction in the Context of the Bladder-Brain Connection - Ilse Groenendijk.pdf

Introduction 15
1.5 DYNAMIC BRIAN IMAGING
The brain represents about 2% of the adult total body weight but consumes an esti- mated 20% of the oxygen entering the body. To conserve energy, the brain regulates its blood flow such that active neurons with increased metabolism receive more blood than relatively inactive neurons. Dynamic brain imaging is predicated on this principle and therefore an indirect measurement of neuronal activity. In positron emission tomogra- phy (PET) the increased decay of unstable positron-emitting isotopes in areas with an increased metabolism is used to study changes in regional cerebral blood flow.2, 30, 31 This technique is minimally invasive except for the injection of isotopes in the bloodstream. In functional magnetic resonance imaging (fMRI), the blood oxygenation level-dependent (BOLD) signal is used, which is a signal intrinsic to the brain, without the radioactivity used in PET. Hemoglobin in blood slightly distorts the magnetic resonance properties of hydrogen nuclei in its vicinity. Therefore, the change from oxygenated blood (with hemoglobin), to deoxygenated blood (without hemoglobin) is detectable using fMRI.2, 31 Its non-invasive character makes repeated observations possible, which constitutes a major advantage over PET.31 The strength of the magnet in the MRI scanner corresponds with the resolution of the acquired data and is expressed as Tesla. The first 7-Tesla MRI scanners have been installed in the Netherlands, allowing to acquire high resolution im- ages and thus a more accurate understanding of the organization in the human brain.32
Most researchers using neuroimaging perform group analyses which reveal a group’s average brain response. These results cannot be translated to individuals, however, as we do not know the responses and inter-individual differences in individuals. Clinical application of this technique to detect abnormalities in activity patterns in individuals with specific symptoms is therefore not yet achieved. Defining the involved brain areas and activity patterns of the LUT in healthy individuals is a necessary step towards using this technique in clinical practice.
1.6 THERAPY
Different treatments are available in the field of functional urology, ranging from con- servative/non-invasive to pharmacological and invasive therapies. As most of the LUT diseases are non-lethal, the decision to undergo an invasive treatment should always be a shared decision between the patient and urologist in which the risks and benefits have to be considered carefully. Usually a step-wise approach is executed starting with conservative therapies.20, 33, 34
Conservative therapies include life style interventions (e.g., weight loss, fluid intake or physical exercise) and pelvic floor muscle training. Although effectiveness of these non-
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