Ventriculomegaly is a common imaging finding in many types of conditions. It is difficult to determine whether it is related to true hydrocephalus or to an atrophic process by using only imaging procedures such as MR imaging after traumatic injury, stroke, or infectious disease. Diffusion tensor (DT) imaging can distinguish the compression characteristics of white matter, indicating that increased diffusion anisotropy may be related to white matter compression. In this preliminary study, the authors compared the DT imaging findings of ventriculomegaly with those of chronic hydrocephalus or atrophy to clarify the potential of diffusion anisotropy in the identification of hydrocephalus.
Ten patients with chronic hydrocephalus, 8 patients with atrophy (defined by conventional devices and surgical outcome), and 14 healthy volunteers underwent DT imaging. Images were acquired before and after shunting or once in cases without shunting. The fractional anisotropy (FA) values at many points around the lateral ventricle were evaluated.
The FA patterns around the lateral ventricle in the chronic hydrocephalus and atrophy groups were different. Especially in the caudate nucleus, FA was increased in the chronic hydrocephalus group compared with the atrophy group. Furthermore, the FA values returned to normal levels after shunt placement.
Assessment of the FA value of the caudate nucleus may be an important, less invasive method for distinguishing true hydrocephalus from ventriculomegaly. Further research in a large number of patients is needed to verify the diagnostic ability of this method.
Abbreviations used in this paper: ant-IC = anterior limb of internal capsule; DT = diffusion tensor; FA = fractional anisotropy; FSE = fast spin echo; ICH = intracranial hemorrhage; ICP = intracranial pressure; iNPH = idiopathic normal-pressure hydrocephalus; MD = mean diffusivity; post-IC = posterior limb of the internal capsule; PVH = periventricular hyperintensity; SAH = subarachnoid hemorrhage; VOI = volume of interest.
Address correspondence to: Eiichi Ishikawa, M.D., Ph.D., Department of Neurosurgery, Institute of Clinical Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan. email:
Please include this information when citing this paper: published online August 21, 2009; DOI: 10.3171/2009.7.JNS09550.
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