The mean signal intensity curve generated from the MR perfusion images and can measure the alteration in capillary leakiness/permeability and vascular shunting of the tumor bed. The aim of this study was to analyze the mean signal intensity curve and evaluated the patterns shown by different brain tumors in dynamic susceptibility contrast enhanced MR Perfusion imaging.
Method: A total 30 patients with histopathological confirmed brain tumor were evaluated the mean perfusion curve. The sloping angle of the signal drop and the percentage of signal recovery were determined from the mean signal intensity curve. Based on these findings the various patterns of the mean perfusion curve were evaluated.
Results: The range of the signal drop angle and signal recovery percentage of meningioma were 3.610 to 6.80 and 3.99 % to 120%, hemangiopericytoma 8.350 to 8.40 and 45.69% to 64.02%, Schwannoma was 4.62 to 10.2 and 53.87 to 76.02 , high grade glioma 5.60 to 9.30and 9.8% to 72.3%, pilocytic astrocytoma was 7.10 to 8.750 and 9.5% to 100%, low-grade glioma was 6.30 and 98.8%, Oligodendroglioma was 5.1 to 6.2 and 44.48% to 91.66%, hemangioblastoma was 4.880 to 9.790 and 52.05% to 54.16% , meduloblastoma was 4.60 to 4.70 and 65.28% to 66.18%, central neurocytoma was 5.990 and 71.89%, anaplastic Ependymoma 5.530 and 71.17%, lymphoma was 6.30and 120 % and metastasis was 6.50 to 10.070 and 71.17% to 71.92%.
Four types of mean signal intensity curve were observed based on signal drop and signal recovery.
Type I: The signal recovery overshoot above the base line after the first pass of contrast. This pattern was seen in 1 case of primary CNSlymphoma and 1 case of meningioma.
Type II: The signal recovery reach to the baseline after the first pass. This pattern was seen in 1case of low-grade fibrillary astrocytoma, 1 case of oligodendroglioma and 2 cases of pilocytic astrocytomas
Type IIIA: The signal recovery upshot, but which never reached the baseline. This pattern was seen in3 cases of meningioma, 2 cases of high grade gliomas, 1 case of pilocytic astrocytoma, 2 cases of Schwannoma, 2cases of meduloblastomas, 2 cases of oligodendroglioma, 1 case of neurocytoma, one case of hemangioblastoma, 1 case of hemangiopericytoma and 2cases metastasis
Type IIIB: The signal recovery upshot after the dip, but which never reached the baseline was seen in 1 case glioblastoma, 1 case of pilocytic astrocytoma and 1 case of meningioma (case 4), in addition to a metastasis.
Type IV: The signal recovery was flat after the first pass. this type was seen in a case of highgradeglioma and 1 case of meningioma
Conclusion: The MPC along with the with perfusion maps and conventional cross-sectional imaging, can help in the characterization of intracranial tumors