The Value of SWAN and ~1H-MR Spectroscopy 3D Multi-voxel Imaging in Grading Astrocytoma

Purpose To evaluate the grading effectiveness of combined MR T2 star weighted angiography (SWAN) and 1 H-MR spectroscopy 3D multi-voxel imaging in patients with astrocytoma.Materials and Methods 57 patients with primary astrocytoma underwent pre-operative MR examination.The astrocytomas were graded as low or high based on conventional MR imaging findings and compared to histopathologic grading.The sensitivity and specificity of conventional MR examination for identifying high-grade astrocytoma were calculated.These patients also underwent SWAN and 3D multi-voxel 1 H-MRS examination on a 1.5T scanner (GE,HD) for grading and compared to histopathologic grading.Receiver operating characteristic analyses were performed to determine optimum thresholds for astrocytoma grading.The sensitivity and specificity were the combined SWAN and MRS imaging for identifying high-grade astrocytoma were calculated.Results Sensitivity and specificity for determining high-grade astrocytoma using conventional MR were 75.3% and 70.8%.A threshold value of grade two of intratumor susceptibility signal intensity on SWAN had sensitivity and specificity of 84.8% and 90.9% in determining high-grade astrocytoma.A threshold value of Cho/NAA=2.35 provided sensitivity and specificity of 86.4% and 81.2%.The combination of Cho/NAA and the degree of intratumor susceptibility signal intensity on SWAN resulted in sensitivity and specificity of 93.2% and 81.0% respectively.Conclusion Compared with conventional MR imaging,combined Cho/NAA and the degree of intratumoral susceptibility signal intensity on SWAN can significantly increase sensitivity and decrease false negative rate in grading astrocytoma.