Beyond DVH
Tiziana Rancati, Claudio Fiorino in Modelling Radiotherapy Side Effects, 2019
With regards to the 3D DVM, voxel-wise comparisons in a common coordinate system represent a suitable strategy to reveal local differences across individuals within a whole volume at low spatial scales. After a pre-processing step of inter-individual spatial alignment, voxel-wise statistical tests are then used to produce 3D maps depicting the localization of regions where statistically meaningful differences between or within groups may exist. These methods are inspired from the voxel-based morphometry (Ashburner et al. 2000). Applied to toxicity studies, the works undertaken in this field have allowed the identification of more predictive sub-regions within the organs in several locations (Heemsbergen et al. 2010; Acosta et al. 2013; Drean et al. 2016b; Ziad et al. 2012; Rao et al. 2012; Monti et al. 2017; Palma et al. 2016).
Neuroimaging
John O'Brien, Ian McKeith, David Ames, Edmond Chiu in Dementia with Lewy Bodies and Parkinson's Disease Dementia, 2005
As well as visual rating and volumetric methods of analysis, unbiased voxel- based methods have also been applied to DLB. Burton et al (2002) reported the first study using voxel-based morphometry in DLB. This method has some methodological advantages over previous techniques, since it is not operator- dependent and examines changes in all parts of the brain, rather than only in predetermined regions. Burton et al (2002) showed gray matter loss in temporal and frontal lobes and in insular cortex in DLB compared with controls. Compared with AD, DLB subjects showed relative preservation of gray matter volume in the medial temporal lobe, hippocampus and amygdala, again strongly confirming previous studies that had used visual ratings and volumetric analysis.
Neuroimaging studies of individuals with Down syndrome
Vee P. Prasher in Down Syndrome and Alzheimer’s Disease, 2018
Voxel-based morphometry (VBM) is an automated technique for examining group differences in whole brain morphology. A recent study used VBM to compare brain anatomy in non-demented adults with DS with that in healthy controls.43 The authors reported that individuals with DS had significant decreases in grey matter in the cerebellum, cingulate gyrus, left medial frontal lobe, right middle/superior temporal gyrus and the CA2/CA3 region of the left hippocampus, compared with healthy controls. Individuals with DS also showed significant decreases in white matter throughout the inferior brainstem compared with healthy controls. In contrast, individuals with DS were reported to show significant increases in grey matter in a superior/caudal portion of the brainstem and left parahippocampal gyrus compared with healthy controls. Individuals with DS showed significant increases in bilateral white matter in the parahippocampal gyri compared with healthy controls. Furthermore, individuals with DS had significant increases in ventricular cerebrospinal fluid compared with healthy controls. These results are broadly consistent with the findings of previous hand-traced region-of-interest (ROI) studies. For example, the ROI studies also reported that individuals with DS showed volume reductions in the hippocampus, cerebellum and frontal regions36,51 and increases in parahippocampal formation,38 compared with healthy controls. VBM is claimed to offer a more fine-tuned approach to the study of differences in regional brain anatomy. However, it is technically more complex than ROI methods and it includes statistical modelling assumptions that may not apply to populations known to have marked abnormalities in brain anatomy. Thus at present it is uncertain whether VBM offers a more accurate description of brain anatomy in DS than ROI techniques.
Regional brain morphology of the primary somatosensory cortex correlates with spicy food consumption and capsaicin sensitivity
Published in Nutritional Neuroscience, 2023
Pengfei Han, Tao Su, Hong Chen, Thomas Hummel
The primary objective of the current study was to investigate whether habitual spicy food consumption relates to brain anatomical features. Using magnetic resonance imaging we applied voxel-based morphometry which is a relatively straightforward method that quantifies the amount of gray matter per voxel, to the brain anatomical images acquired. We adopted a modified 3-item spicy food consumption questionnaire that covers (1) the spicy eating frequency, (2) the preferred degree of food spiciness and (3) the duration of spicy dietary habits [12], which gives a comprehensive picture of spicy food consumption matrices [14]. We hypothesized that habitual spicy food intake is related to decreased capsaicin sensitivity and intensity perception. On the anatomical level, habitual spicy food intake was expected to relate to an increased GMV of the brain regions representing the oral cavity, mainly the primary somatosensory cortex. Further, as the same central pathway is involved in the processing of both oral and intranasal trigeminal stimuli [15–17], and spicy food consumption is accompanied by intranasal exposure to pungent volatiles (e.g. allyl isothiocyanate from mustard and wasabi, gingerol from ginger). The study also assessed the intranasal trigeminal perception to explore whether habitual spicy dietary behavior is also associated with changes in intranasal trigeminal perception.
Implications of structural and functional brain changes in amyotrophic lateral sclerosis
Published in Expert Review of Neurotherapeutics, 2018
Thanuja Dharmadasa, William Huynh, Jun Tsugawa, Yoshimitsu Shimatani, Yan Ma, Matthew C. Kiernan
Structural MRI (sMRI) is based on high resolution T1-weighted volumetric MRI, generating images with good tissue contrast that can be used to analyze both grey (cortical) and white (subcortical) matter [20]. It remains the investigation of choice for analysis of grey matter in ALS [21], enabling in vivo localization of focal cortical atrophy and identification of regional differences in tissue volume [22]. Two types of volume analyses are commonly used in sMRI: (i) voxel-based morphometry (VBM) and (ii) surface based morphometry (SBM). VBM is a fully automated, post-processing, whole brain analysis technique that measures relative grey and white matter volumes through voxel-wise comparisons, and infers regional brain atrophy patterns between groups of subjects [23]. SBM is based on the reconstruction of the boundaries between grey and white matter, allowing for individual morphometry measurements of cortical thickness independent of cortical folding pattern [24,25].
Relationship between whole blood omega-3 fatty acid levels and dorsal cingulate gray matter volume: Sex differences and implications for impulse control
Published in Nutritional Neuroscience, 2020
Valerie L. Darcey, Goldie A. McQuaid, Diana H. Fishbein, John W. VanMeter
Three independent raters blind to the participant identity visually verified quality of structural scans for inclusion in a Voxel-Based Morphometry (VBM) analysis. Raters scored structural scans for degree of artifacts, which may impact the tissue classification algorithm (i.e. gross quality problems such as phase wrap or clipped brain, ringing, and other motion related artifacts) on a 0–5 point scale, where 0 indicates a scan free from visible artifact and 5 represents a scan of the poorest quality due to the severe presence of that specific artifact. For each of the 3 raters, a weighted summary score was computed. Summary scores were in good to excellent agreement (intraclass correlation coefficient = 0.873, 95% confidence interval = 0.798–0.919 [SPSS 24 based on mean-rating (k = 3), absolute-agreement, 2-way mixed-effects model]).47 An average weighted score of the 3 raters was assigned to each structural scan. Scans with an average weighted quality score > 9 were considered to be of extremely poor quality. These scans were subsequently reviewed/confirmed by the authors and excluded from the pool of scans suitable for VBM analysis.
Related Knowledge Centers
- Brain Asymmetry
- Cerebral Hemisphere
- Handedness
- Image Registration
- Morphometrics
- Neuroanatomy
- Neuroimaging
- Hippocampus
- White Matter
- Grey Matter