Value of MRI in Brain Ring enhancing lesions

Abstract

The aim of this study : to evaluate the role of contrast enhanced MRI to distinguish the ring enhancingbrain lesions with histological findings and clinical diagnosis as reference standardPatients and methods : This prospective study was done from may 2011 to may 2012. 20 patients withvarious ring enhancing lesions in the brain detected by MRI with different clinical conditions , fifteenmales and 5 females between 13-63years age MR imaging was performed with MRI of (Philips - achiva 1.5Tesla 16 channels). Routine sequences of T1, T2 and FLAIR spin echo sequences with IV contrast ,gadolinium were carried out .Statical analysis include sensitivity , specificity and accuracy accounting inthis studyResults : Contrast enhanced MRI revealed 4 cases of non neoplastic and 13 cases as neoplastic brainring lesions compared with histopathology which revealed 5 cases of non neoplastic and 15 cases ofneoplastic brain ring enhancing lesions. Sensitivity of MRI for non neoplastic lesions was 80% andspecificity is 86.6% .Sensitivity of MRI for neoplastic lesions was 86.6% and specificity was 80%.Accuracy of MRI in differentiation of ring enhancing brain lesion either neoplastic or non neoplastic was85%. MRI of neoplastic ring lesions revealed 4 cases as metastasis and 9 cases as primary tumor of highgrade astrocytoma(globlastoma multiforme ) while histopathology reveal 5 cases metastasis and 10 casesglioblastoma multiforme .Sensitivity of MRI for metastatic ring lesion was 80% and specificity was81.8% .Sensitivity of MRI for primary neoplastic tumor is 81.8% and specificity was 66.6% .MRI for non neoplastic ring lesions included 3 cases as abscess , on case resolving hematoma whilehistopathology revealed 5 cases of non neoplastic ring lesions , 3 cases pyogenic abscess , one caseresolving hematoma and one case radiation necrosisConclusion and recommendation : The accuracy of differentiation of the neoplastic from nonneoplastic ring enhancing lesions by MRI is 85%. In doubtful cases diagnosis improved by use offurther sequences like diffusion – perfusion studies and nuclear studies .