Gray matter enhancement

In the subacute phase, arterial vascular enhancement peaks at 1-3 days. Large infarcts will also demonstrate meningeal enhancement that may represent reactive hyperemia, which peaks at 2-6 days. Both arterial and meningeal enhancement typically resolve by 1 week [11]. Parenchymal enhancement also occurs during this phase gray matter enhancement can appear band-like or gyriform (Fig. 6.5). This is secondary to disruption of the BBB and restored tissue perfusion from a recanalized occlusion or collateral flow. 

Lieberman, D.M., Laske, D.W., Morrison, P.F., Bankiewicz, K.S. and Oldfield, E.H. (1995) Convection-enhanced distribution of large molecules in gray matter during interstitial drug infusion. J. Neurosurg, 82, 1021-1029. 

Fig. 6.1. Source images of a dynamic susceptibility contrast-enhanced series in a healthy volunteer, acquired 20-50 s after bolus injection during the bolus passage the signal decrease in gray matter is more prominent than that in white matter. After the bolus passage, the signal returns to normal...

In most cases of the thoracolumbar infarction, the swollen cord shows peripheral enhancement of the central gray matter. The concomitant enhancement of the cauda equina was reported first by Friedman and Flanders in 1992 (Fig. 17.8). This phenomenon is a characteristic finding in the course of spinal cord ischemia which might involve the cord itself and the ventral cauda equina as well, which is composed of motor fibre bundles (Amano et al. 1998). It indicates disruption of the blood-cord barrier as well as reactive hyperemia (Friedman and Flanders 1992 Amano et al. 1998). The differential diagnosis of contrast enhancement of the cauda equina includes transverse myelitis, bacterial or viral meningitis, and spinal metastasis. 

Fig. 1.6. a Axial contrast-enhanced Tl-weighted image with a small developmental venous anomaly (DVA) in the left hemisphere. The typical transcerebral draining vein is diagnostic. However, the epileptic seizures of the patient are not associated with the DVA. b,c T2-weighted (b) and inversion recovery sequence (c) nicely reveal the nodular subependymal heterotopic gray matter in the wall of the left ventricle. This cellular migration disorder is the cause of the seizures... 

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