ELSEVIER Brain & Development 1996; 18:394-399 Original article Three-dimensional brain visualization for metachromatic leukodystrophy Reiko Minamikawa-Tachino a,*, Yuji Maeda b Issei Fujishiro c, Kohji Itoh d, Akira Satake d, Shigeki Aoki e, Hideo Yamada f, Yoshiyuki Suzuki d, Hitoshi Sakuraba d a Computer Center, The Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tolo, o 113, Japan b Doctoral Program in Engineering, Uniuersity of Tsukuba, Tsukuba, Japan c Department of Information Sciences, Faculty of Science, Ochanomizu University, Tokyo, Japan d Department of Clinical Genetics, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan e Department of Radiology, Faculty of Medicine, The University of Tokyo, Tok3'o, Japan f Department of Pediatrics, Tokyo Metropolitan Komagome Ho.spital, Tokyo, Japan Received 4 December 1995; accepted 28 March 1996 The basic understanding of many neurogenetic diseases requires study of the clinical, biochemical, and pathologi- cal aspects. To study the pathological aspects, the organs affected by the disease must be observed. We have used volume visualization techniques to create three-dimensional (3D) brain images of a patient with late infantile metachromatic leukodystrophy (MLD). The 3D brain images showed clearly, stereographically, and non-invasively the intracerebral lesion. This lesion, which indicated hyperintensity in magnetic resonance (MR) images, extended throughout the periventricular white matter. The 3D brain images are provided to integrate information. Volumetric ray-casting was useful in obtaining directly images of the entire brain and in allowing an intuitive understanding of the extension of the lesion in three dimensions and of the extent of the defects in the MLD brain. Isosurfacing facilitated a clear extraction of the lesion located by volumetric ray-casting. Each technique used in this study played a role in visualization and their use was complementary. 3D brain images will promote morphological investigation of neurogenetic diseases. Keywords: Metachromatic leukodystrophy; Magnetic resonance imaging; Volume visualization; Three-dimensional image; Volumetric ray-casting; isosurfacing 1. INTRODUCTION Metachromatic leukodysthrophy (MLD) is an autosomal re- cessive neurogenetic disease affecting myelin metabolism. It is caused by arylsulfatase A (ASA) deficiency. An impaired degra- dation of galactosyl sulfatide(cerebroside sulfate) results in pro- gressive demyelination in the cerebral white matter and periph- eral nerve and a variety of neurological symptoms [1]. In most cases of MLD, the disease becomes manifest at 12-18 months after birth, the clinical course is slowly progressive, and death ensues within several years after the onset of the disease (late infantile form). There are rare cases of later onset with milder clinical manifestations (juvenile and adult forms) * Corresponding author. Fax: (81) (3) 3823-2965; e-mail: tachino@rinshoken.or.jp Recent advances in biochemistry and molecular genetics have revealed the pathogenesis of many neurogenetic diseases, includ- ing MLD [2]. However, the pathophysiology of neural dysfunc- tion has not yet been fully elucidated. Correlative studies of the clinical, biochemical, and pathological aspects of these diseases are necessary. Volume visualization uses computer graphics techniques to assist researchers to better understand three-dimensional (3D) structures. In medical investigation, volume visualization has been used to visualize the anatomic structure and pathology of diseases for the last decade [3,4]. Images of consecutive slices of the brain have been acquired by tomographic techniques, such as computerized tomography (CT) and magnetic resonance imaging (MRI). A 3D volumetric data set was reconstructed from the consecutive slices and projected onto a two-dimensional (2D) image plane. Not only the brain surface but also the internal structure was visualized from the volumetric data sets. The 0387-7604/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved. PH S03 87- 7604(96)00040-X