Perfusion-Weighted MR Imaging Studies in Brain Hypervascular Diseases: Comparison of Arterial Input Function Extractions for Perfusion Measurement
D. Ducreuxa,b,d,
I. Buvatb,
J.F. Mederc,
D. Mikulisa,d,
A. Crawleyd,
D. Fredyc,
K. TerBrugged,
P. Lasjauniasa and
J. Bittoune
a Department of Neuroradiology, C.H.U. de Bicêtre, Paris XI University, Le Kremlin-Bicêtre, France
b INSERM U 678, CHU Pitié-Salpêtrière, Paris, France
c DIMF, Centre Hospitalier Sainte-Anne, Paris V University, Paris, France
d Medical Imaging Department, Toronto Western Hospital, Toronto, Ontario, Canada
e CIERM, CNRS U2R2M, Le Kremlin Bicêtre, France
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Fig 1. A, Arterial region of interest set on the right (red) or left (blue) MCA or right (green) or left (yellow) PCA in the regional and regional scaled estimations.
B, Tissular region of interest set on the right Th (upper) and right CO (lower).
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Fig 2. Automated AIF extraction used in regional scaled and global methods. Arterial voxels (red, upper image) are superimposed over MR PWI series to check their anatomic matching with brain arteries. Single AIF curve (red, lower image, in arbitrary unit [AU]) derived from local selected AIF curve (blue) is fitted with a gamma function to eliminate recirculation (yellow).
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Fig 4. Comparison of the CBF distribution measurements in Th locations of patients with brain hypervascular disease among the 4 AIF estimations methods, compared with a beta distribution. All the AIF estimation methods have a beta pattern for the CBV and CBF measurements in all locations (only CBF in Th is shown here).
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Fig 5. Differences between CBV and CBF parameter color-scaled maps with local (A), regional (B), regional scaled (C), and global (D) AIF estimations in a patient with brain AVM. Note that AIF curves are sharper with the regional and regional scaled methods, mainly because of AIF positioning and increased CBF values in gray matter cortices (green). Unlike the observations in volunteers, CBV and CBF images obtained with the 4 AIF estimation approaches were not that similar.
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Fig 6. AIF of a left occipital brain AVM (A, -B) with visualization of the arteriovenous shunt (red voxels inside the left occipital lobe). T2* section (C) shows T2-weighted left parietal abnormal areas related to gadolinium-chelate magnetic susceptibility effect in abnormal vessels; and color scale parametric CBV (D), CBF (E), and MTT (F) maps computed with the regional scaled method show high-flow disturbances in this area. Note that hemodynamic disturbances are seen remote from the nidus over the left CO (arrow), regardless of the AIF estimation method used.
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Fig 7. Graph shows patients’ PWI abnormalities (hypoperfusion [Hypo], hyperperfusion [Hyper], venous congestion [lswb]Cong], or Normal) found in the different AIF estimation methods. Note that PWI abnormalities may be bilateral. All PWI results varied among the different methods except for 14 patients who had the same PWI abnormalities regardless of the AIF estimation method.
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results for the 4 PWI parameters (CBV Th, CBV CO, CBF Th, CBF CO) in volunteers (A) and patients (B). The plot with the smallest area corresponds to the most accurate AIF estimate.