Practical Visualization of Internal Structure of White Matter for Image Interpretation: Staining a Spin-Echo T2-Weighted Image with Three Echo-Planar Diffusion-Weighted Images

Images of a 63-year-old man with right parietal glioblastoma.

A, Conventional fast spin-echo T2-weighted image shows peritumoral white matter edema around the right lateral ventricle that is pressed down by the tumor. The precise location of the right corona radiata and the posterior limb of the left internal capsule are not apparent on this image.

B, Color-coded image constructed from three inverted orthogonal diffusion-weighted images. Fibers running superoinferiorly, anteroposteriorly, and transversely are displayed with red, blue, and green, respectively. Because the T2 shine-through phenomenon counteracts the contrast caused by diffusion, the peritumoral edema is not distinct from normal brain.

C, Color-coded image created from three orthogonal ADC maps.

D, Image after registration and addition of the images shown in A and B has a contrast similar to and a quality superior to those of the image shown in C. The right deep white matter with edema is clearly resolved into three parts: from medial to lateral, the corpus callosum (green, arrow), corona radiata (orange, arrowhead), and superior longitudinal fasciculus (blue, open arrow). The posterior limb of the left internal capsule can be easily identified by the red hue (open arrowhead).

Superposed color images obtained in a 41-year-old woman with dyskinesia. Diagnosis has not yet been established.

A, Axial image. The white matter lateral to the posterior horn of the lateral ventricle appears to be divided into four layers. They are probably, from medial to lateral, the tapetum (red, arrowheads), internal sagittal stratum (dark blue, open arrowheads), external sagittal stratum (bright blue, arrows), and white matter containing the superior longitudinal fasciculus (red, open arrows). The pulvinar of the thalamus appears yellowish green (*).

B, Coronal image. The posterior limbs of the internal capsules are identified as red bands (arrowheads). The external and the extreme capsules (cannot be separated) are seen as reddish sheets (arrows). The superior longitudinal fasciculi appear greenish blue (open arrows). The cingula appear blue (open arrowheads). The inferolateral parts of the temporal lobes show artifact because of the failure to correct severe distortion.

Images obtained in an 84-year-old man with multiple lacunar hemorrhages and infarcts.

A, Spin-echo T2-weighted image shows multiple small foci of hyper- and hypointensity in the basal ganglia and thalami. Linear hyperintensity (arrow) is seen near the right posterior limb of the internal capsule. Spatial relations between the internal capsule and these lesions are unclear.

B, On the superposed image, the posterior limbs and anterior limbs of the internal capsule appear red and blue, respectively. They are easy to identify, and the right internal capsule is situated medially to the linear hyperintensity (arrow).

Images of a 6-month-old male patient with epilepsy. No abnormality is found by MR imaging examination.

A, Spin-echo T2-weighted image.

B, Superposed color image. The white matter anterolateral to the inferior horn of the lateral ventricle appears red (arrows). This is probably part of the uncinate fasciculus running up from the temporal pole to the inferior margin of the extreme and external capsule. The pyramidal tract in the basis pontis (red, open arrows) is distinguished from the transverse pontine (pontocerebellar) fiber (green) by the difference in hue. Both the inferior (lateral part) and superior (medial part) cerebellar peduncles appear red (arrowheads) between the fourth ventricle and the middle cerebellar peduncle (blue, open arrowheads).

Coronal view images of a 45-year-old woman with lymphoma in the splenium of the corpus callosum.

A, Spin-echo T2-weighted image shows white matter edema around the lateral ventricles. The corpus callosum cannot be clearly recognized.

B, Superposed color image. The corpus callosum is clearly identified as a green structure (arrow). The white matter lateral to the left lateral ventricle appears to have at least three layers: medial to lateral, red (tapetum, arrowhead), blue (internal and external sagittal strata, open arrow), and red layers. The asymmetrically widened tapetum on the left indicates extension of peritumoral edema in this region.

Left sphenoid ridge meningioma in a 54-year-old woman.

A, Spin-echo T2-weighted image.

B, Superposed color image shows the meningioma with certain colors: the anterior and posterior parts appear violet, and the left and right parts are green, which can be interpreted (although it has not been confirmed histologically) to mean that this tumor, as a whole, has a radially oriented internal structure. The posterior limb of the left internal capsule (arrow) appears redder and thinner than the contralateral limb (arrowhead). This indicates that the tumor compresses the limb and deflects its direction vertically.