A new metric to measure shape differences in fMRI activity

Siddharth Khullar, Andrew M. Michael, Nicolle Correa, Tulay Adali, Nathan Cahill, Stefi A. Baum, Vince Daniel Calhoun

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We present a novel shape metric for quantification of shape differences between the spatial components obtained from independent component analysis (ICA) of group functional magnetic resonance imaging (fMRI) data. This metric is utilized to measure the difference in shapes of the activation regions obtained from different subjects within a group (healthy controls or patients). The parameters comprising the metric are computed for each pixel on the outermost contour (edge) of an activation region for each slice. These parameters are in the form of (r, θ) pairs that may be interpreted as the length and orientation of a vector originating from the centroid of the activation region to the pixel belonging to the boundary contour. Using this information we extract three features that quantify the shape difference between the two shapes under observation. The reference and observation shapes may be selected in two ways: (a) activation maps from two different subjects or (b) mean activation map compared against subject-wise activations, as obtained from group ICA. We present different methods to visualize the shape differences, thus providing a tool to observe the spatial differences within a group or across groups. In addition to the above results, we also address a few special cases where two or more activation contours are present in a single slice and present potential solutions for accounting for these regions as special measures. Our results show that this metric has utility in creating a better understanding of the variability in brain activity among different groups of subjects performing the same task.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7962
DOIs
StatePublished - 2011
Externally publishedYes
EventMedical Imaging 2011: Image Processing - Lake Buena Vista, FL, United States
Duration: Feb 14 2011Feb 16 2011

Other

OtherMedical Imaging 2011: Image Processing
CountryUnited States
CityLake Buena Vista, FL
Period2/14/112/16/11

Fingerprint

magnetic resonance
Chemical activation
Magnetic Resonance Imaging
Observation
activation
Independent component analysis
Control Groups
Brain
Pixels
pixels
centroids
brain

Keywords

  • fMRI
  • group ICA
  • shape metrics

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Khullar, S., Michael, A. M., Correa, N., Adali, T., Cahill, N., Baum, S. A., & Calhoun, V. D. (2011). A new metric to measure shape differences in fMRI activity. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE (Vol. 7962). [79624K] https://doi.org/10.1117/12.878219

A new metric to measure shape differences in fMRI activity. / Khullar, Siddharth; Michael, Andrew M.; Correa, Nicolle; Adali, Tulay; Cahill, Nathan; Baum, Stefi A.; Calhoun, Vince Daniel.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 7962 2011. 79624K.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Khullar, S, Michael, AM, Correa, N, Adali, T, Cahill, N, Baum, SA & Calhoun, VD 2011, A new metric to measure shape differences in fMRI activity. in Progress in Biomedical Optics and Imaging - Proceedings of SPIE. vol. 7962, 79624K, Medical Imaging 2011: Image Processing, Lake Buena Vista, FL, United States, 2/14/11. https://doi.org/10.1117/12.878219
Khullar S, Michael AM, Correa N, Adali T, Cahill N, Baum SA et al. A new metric to measure shape differences in fMRI activity. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 7962. 2011. 79624K https://doi.org/10.1117/12.878219
Khullar, Siddharth ; Michael, Andrew M. ; Correa, Nicolle ; Adali, Tulay ; Cahill, Nathan ; Baum, Stefi A. ; Calhoun, Vince Daniel. / A new metric to measure shape differences in fMRI activity. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 7962 2011.
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