The Influence of Gliomas and Nonglial Space-occupying Lesions on Blood-oxygen-level–dependent Contrast Enhancement
Axel Schreiber
,a,
Ulrich Hubbea,
Sargon Ziyeha and
Jürgen Henniga
a From the Departments of Neurology (A.S.), Neurosurgery (U.H.), Neuroradiology (S.Z.), and Radiology (J.H.), Albert-Ludwigs-University, Freiburg, Germany.
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FIG 1. Adjacent to nonglial tumors, a normal volume of BOLD contrast enhancement was elicited.
A, Case 4. Arrows point to a small chronic abscess in the left precentral gyrus within the hand area. Upper row (T2-weighted turbo spin-echo sequence: 4500/120/1) shows edema apparently confined to the white matter. A narrow band of cortex is spared (open arrowheads). Lower row (echo-planar image: 3500/84/1), shows BOLD contrast enhancement in the cortex directly adjacent to the edema (arrowheads). Neither the edema nor the lesion affect the BOLD contrast enhancement.
B, Case 10. Arrows point to a metastatic lesion located in the right postcentral gyrus, slightly superior to the hand area. Arrowheads point to the functional activation of the sensorimotor cortex. Upper row is an overlay of the activation map onto the full head volume (MPRAGE: 9, 7/4/1 [TR/TE/excitations]). Lower row is an overlay onto the functional echo-planar sections (3500/84/1). In the ipsilateral hemisphere, the activation is squeezed between the swollen pre- and postcentral gyrus, but is not reduced. There is very little activation in the contralateral hemisphere.
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FIG 2. Case 20. The patient was suffering from an anaplastic astrocytoma invading the precentral gyrus. She presented with focal epileptic seizures of the face on the left side but did not have a motor deficit. Overlay of the activation map onto the functional echo-planar image (3500/84/1) shows activation nearly symmetrical in the upper two sections lining the  -shaped hand-motor area. There is less activation in the ipsilateral sensorimotor cortex on the lower two sections. The signal hyperintense parts of the sensorimotor cortex do not display BOLD contrast enhancement. Region of interest 1 is the cluster of activated voxels in the most medial part of the pre- and postcentral gyrus. Region of interest 2 is on the lateral continuation of the pre- and postcentral gyrus within an area of T2 signal hyperintensity of the cerebral cortex. The signal hyperintensity likely indicates gliomatous infiltration; in this case, histologic analysis of the resected specimen showed diffuse infiltration of the cortex. The interval of the signal intensity of region of interest 1 shows task-related signal changes (BOLD contrast enhancement) of approximately 6%, with hemodynamic delays of one to three images (gray bars indicate stimulation measurements). Region of interest 2 does not show BOLD contrast enhancement, although the analogous area in the left hemisphere is strongly activated.
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FIG 3. Case 6. Arrows point to a metastasis of a neuroendocrine active lung cancer located in the left precentral gyrus near the hand area. A large edema extends into the pre- and postcentral gyrus. The patient presented with focal epileptic seizures starting at the right hand, generalizing secondarily. Arrowheads point to clusters of activation in the sensorimotor cortex overlaid onto the functional echo-planar sections (3500/84/1). On the ipsilateral hemisphere, the functional activation is far less than on the contralateral hemisphere. The parieto-occipital clusters on the lowest section are attributable to head motion
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