Intratumoral Small Vessels on SWI Can Differentiate Primary from Secondary Brain Tumors

PURPOSE: Previous study has shown that SWI is superior to show small vessels and micro- hemorrhage in brain tumors.
The purpose of this study is to differentiate brain lymphoma, glioma and metastasis based on intratumorous small vessels.
MATERIALS AND METHODS: There were eight patients with brain lymphoma, 12 glioma, three gliosis and 24 metastatic
carcinoma. All cases received histological diagnosis. All MR images were review by two radiologists and consensus of
interpretation was reached. We evaluate whether there was visible small vessel passing through brain tumors or stop/deviated by
the brain tumors on SWI. Other findings on SWI such as hemorrhage and/or calcifications were also reviewed.
RESULTS: In 8 patients with lymphoma, small vessels passing through in at least one tumor on SWI were identified in all
cases (100%); 5 of them (62.5%) were more apparent on MIP images. Intratumorous calcifications were noted in one case
(12.5%). In glioma, three out of 12 (25%) cases depicted intratumoral small vessels seen on SWI. However, intratumoral
vessels of one case (8.3%) also were noted on TOF MRA images and another two cases on post contrast T1 images which
were excluded from SWI comparison due to motion artifact. In the three gliosis cases, one (33.3%) showed small vessels at
peripheral region of the gliosis on SWI. One (33.3%) showed a small vessel passing through, and one showed hemosiderin
deposition. In all 24 metastatic carcinoma, no small vessels passing through metastatic were noted on SWI. Two cases (8.3%)
depicted cortical vein passing by tumor, 6 cases (25%) showed tiny medullary veins stopped by tumor.
CONCLUSION: If small vessels passing through tumor could be recognized on SWI, it can be reliable to exclude the
possibility of brain metastasis. Lymphoma offers the highest possibility to demonstrate small vessels passing through
tumor as compared with gliosis and brain glioma on SWI.