ROLE OF MAGNETIC RESONANCE SPECTROSCOPY AND DIFFUSION WEIGHTED IMAGING IN DISCRIMINATION BETWEEN BRAIN ABSCESS AND NECROTIC BRAIN TUMORS
Aim: The present study was conducted to determine role of MRS and DWI in differentiating brain abscesses from necrotic brain tumors with the following objectives:
1. To determine signal intensity, diffusion motion of content & ADC values in patients with brain abscess and necrotic brain tumors.
2. To determine assignment of various resonances of chemical component on MRS.
Material & Methods: Descriptive type of observational study conducted in the department of Radio-diagnosis and Modern Imaging, Neurology, Neurosurgery of SMS Hospital Jaipur, Rajasthan. A sample size of 64 subjects for each of two groups at Alpha error 0.05 and power 80% assuming area under ROC 0.7 between Diagnostivity for brain abscess and brain tumor. So for study purpose 64 brain abscess cases and 64 necrotizing brain tumor cases were taken .All patient underwent MRI examination which was performed on PHILIPS INGENIA 3 TESLA MRI. Diffusion weighted Imaging with MRS sequences were taken along with conventional MRI sequences. Validation of MRI findings was done through Histology and/or Follow up. Continuous variables were summarized as mean and standard deviation while nominal/categorical variables as proportions(%).Statistical analysis was applied to find out the Sensitivity, Specificity, PPV, NPV and Accuracy of MRI to discriminate brain abscesses with necrotic brain tumors. P-value < 0.05 was taken as significant.
Results: DWI with MRS was 87.5% Sensitive and 100% Specific in differentiation between brain abscesses and necrotic/cystic brain tumors. The Positive and Negative predictive values and over all Accuracy of MRS and Diffusion WI was 100%, 88.9% and 93.7% respectively.
Conclusion: Spectroscopic and Diffusion weighted MRI are advanced MR techniques that are used to add important physiological and metabolic information to that obtained with conventional MRI and are fast, easy to perform, non-invasive, and provide additional information that can accurately differentiate between necrotic/cystic brain tumors and cerebral abscesses.
Keywords: Brain Abscess, Necrotic Brain Tumor, DWI, MRS.