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Hitoshi Matsuzawa, Ingrid L. Kwee and Tsutomu Nakada

extraction of anisotropic components as anisotropic diffusion vector D app A by isotropic elimination (see Appendix 2 for details). Contrary to intuition, this algorithm calls for very simple implementation processes that ensure immediate clinical application. Only three axial anisotropic diffusion weighted images (DWIs) have to be obtained. The trichromatic characteristics of visible light, 4 namely, elimination of hue by the summation of three primary colors of the same intensity, and correlation of hue (color frequency) to a specific ratio of these three primary

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Junki Ito, Anthony Marmarou, Pál Barzó, Panos Fatouros and Frank Corwin

I n vivo diffusion-weighted magnetic resonance imaging (DWI) is a new magnetic resonance (MR) technique, which, by using additional strong magnetic field gradients, is sensitized to the random, microscopic translational motion of water protons. Apparent diffusion coefficient (ADC) maps can be derived from a series of DWI images obtained with varying magnetic field gradients. Recent findings in experimental cerebral ischemia models indicate that ADCs could provide earlier and more specific information about ischemic tissue damage and its characteristics of

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Masaharu Sakoh, Leif Østergaard, Lisbeth Røhl, Donald F. Smith, Claus Z. Simonsen, Jens Christian Sørensen, Peter V. Poulsen, Carsten Gyldensted, Saburo Sakaki and Albert Gjedde

MCAs (white arrows) is shown. Note the varying gross structures of the medial striate branch of the ACA (black arrows) , which has anastomoses to the MCA, and the difference in the extent of collateral blood supply (arrowheads) depending on the gross structure of the medial striate artery between groups. Fig. 2. Comparison of histological specimens, DW MR images (DWI), and CMRO 2 measurements in ischemic brains in pigs in relation to the magnitude of residual flow after MCA occlusion. a: Pig with poor collateral flow. b: Pig with moderate collateral flow. c

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Masaharu Sakoh, Leif Østergaard, Albert Gjedde, Lisbeth Røhl, Peter Vestergaard-Poulsen, Donald F. Smith, Denis Le Bihan, Saburo Sakaki and Carsten Gyldensted

. Flow chart illustrating the timing of imaging, angiography, and histological studies, as well as the variables measured as they relate to vessel occlusion for each group. A: Permanent MCAO. B: Reperfusion after transient MCAO. DWI = DW imaging. Induction of Focal Cerebral Ischemia Focal cerebral ischemia was transorbitally induced by occlusion of the left proximal MCA and the distal ICA. Bipolar coagulation or Sugita microclips (blade length 2–4 mm, blade width 0.8 mm, holding force 65–70 g) were used to induce permanent MCAO or transient MCAO, respectively

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Arnd Doerfler, Tobias Engelhorn, Sabine Heiland, Thomas Benner and Michael Forsting

decreased further to 64 to 78%. Fig. 3. Representative T 2 -weighted (T2W), DW (DWI), and PW (PWI) images obtained in animals that underwent early craniectomy (Group A) and control animals (Group C) at 4 and 24 hours (h) after MCAO. Fig. 4. Bar graphs demonstrating relative regional (r)CBV in the MCA-supplied cortex (upper) and basal ganglia (lower) at different time points after MCAO. Numbers shown on the x axis indicate times of testing: 1 (4 hours), 2 (24 hours), 3 (48 hours), 4 (72 hours), and 5 (168 hours) post-MCAO. Diffusion

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Takatoshi Sorimachi, Yukihiko Fujii, Naoto Tsuchiya, Takeo Nashimoto, Masatsune Saito, Kenichi Morita, Yasushi Ito and Ryuichi Tanaka

ischemic lesions * Case No. Age (yrs), Sex Initial Occlusion Site Time From Symptom Onset to End of Thrombolysis (min) Occlusion Site After Thrombolysis Systolic Back Pressure (mm Hg) Vol of HIAs on Initial DWI (ml) State of Ischemic Vol mRS Score at 3 Mos Posttreatment 1 70, F rt M 1 proximal 160 none 35 82 0.39 0 2 81, F lt M 1 distal 180 temporal M 3 27 69 −1.54 5 3 85, M lt M 1 proximal 265 frontal M 3 29 26 — dead 4 70, M rt M 1 distal

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Jong Eun Lee, Yone Jung Yoon, Michael E. Moseley and Midori A. Yenari

the ipsilateral cortex (arrows) of a normothermic animal subjected to 2 hours of MCA occlusion followed by 22 hours of reperfusion. B: In contrast, virtually no enhancement is seen in an animal exposed to 2 hours of mild hypothermia. C: Ischemic areas from diffusion-weighted MR images (DWI) and areas of contrast enhancement from T 1 -weighted images (T1W) were measured and computed as the percentage of the ipsilateral hemisphere. Mild hypothermia (33°C) significantly reduced the size of the ischemic lesion on diffusion-weighted MR images and areas of contrast

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Justin S. Smith, Soonmee Cha, Mary Catherine Mayo, Michael W. McDermott, Andrew T. Parsa, Susan M. Chang, William P. Dillon and Mitchel S. Berger

 parietal 1 0 4  temporal 4 1 7  occipital 0 0 1 vol of FLAIR imaging abnormality (cm 3 , mean ± SD)† 82.4 ± 62.3 53.6 ± 40.0 86.7 ± 45.2 vol of edema (cm 3 , mean ± SD)‡ 47.3 ± 31.3 29.0 ± 15.7 46.5 ± 30.1 tumor enhancement incidence, no. of cases (%) 11 (61) 2 (33) 21 (100)  vol (cm 3 , mean ± SD)§ 3.9 ± 7.9 1.1 ± 1.0 18.9 ± 11.5 tumor necrosis incidence, no. of cases (%) 0 (0) 0 (0) 21 (100)  vol (cm 3 , mean ± SD)§ 0 ± 0 0 ± 0 9.0 ± 12.0 postop DWI abnormality

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Kazuhide Furuya, Lidong Zhu, Nobutaka Kawahara, Osamu Abe and Takaaki Kirino

intensity of the lesion was slightly decreased but still recognizable on T 2 -weighted imaging. This finding is in agreement with a previous study in which it was demonstrated that diffusion-weighted imaging could not be used to quantify infarct volume observed on Day 7 because there was no uniform signal in the damaged area. 15 It was also apparent that the damaged area is mainly localized in the brain cortex. Fig. 2. Sequential diffusion-weighted (DWI) and T 2 -weighted (T 2 WI) MR images obtained from either the control or the LPS group 6 hours, 24 hours, 4

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Clinical MR Neuroimaging: Diffusion, Perfusion and Spectroscopy.

Jonathan H. Gillard, Asam D. Waldman, and Peter B. Barker, editors. New York: Cambridge University Press, 2005, 827 pp, illus. ISBN 0–521–82457–5. Price: $330.00.

David Yeh

for clinicians and researchers for understanding how MR spectroscopy (MRS), diffusion, and perfusion imaging work and how they can be applied to the management of patients with neurological disorders. The authors begin with the technical details (relevant to a nonphysicist) on how clinical MR imaging works. The fundamentals and pitfalls of single and multivoxel MRS, as well as the signal characteristics of specific amino acid molecules are first described. The authors then discuss the development of MR diffusion weighted imaging (DWI) and diffusion tensor imaging