E
Normal
NAA
NAA
Cho
Cr
Cr
Cho
Tumor
Example 4 - Grade IV astrocytoma:
incorrect algorithm result
B
D
C
A
(A)
Contrast-enhanced axial T1-weighted image demonstrates lack of enhancement of
the tumor.
(D)
If we continue to analyze the rCBV color map, we can see increased perfusion
(arrow) within the lesion and make the correct diagnosis as high-grade glioma.
(B)
Coronal T2-weighted image, which was used for positioning of the regions of
interest, shows increased signal within the left medial temporal lesion.
(C)
Short TE MRS show an increased Cho/NAA ratio (1.05), which is less than the
algorithm cutoff of 2.2. According to the algorithm, we would stop here and classify this as a low-grade
glioma, even though pathology and other radiologic findings suggest high-grade
glioma.
