Abstract

Background information -Non-invasive and accurate differentiation of brain mass lesions
are important for determining the correct treatment plan and in some cases, may avoid the
necessity of performing a biopsy. Now MRI is being currently used to determine the tumor
nature and extent that is helpful in planning surgery and radiotherapy, even for post therapy
monitoring for tumor recurrence or progression. 30-90% MRI can correctly diagnose
intracranial space occupying lesions of various types. It is clinically very important to
differentiate brain infections from brain tumors, as their plan of management is completely
different.
Materials and Methods - All clinically suspected patients of intracranial space occupying
lesions and already diagnosed patients with intracranial space occupying lesions, who were
referred to the department of Diagnostic Radiology in VIMS and RC underwent MRI. The
images of MRI were evaluated to characterize the space occupying lesions by conventional
and diffusion weighted sequences. Further the study was reviewed by the experienced
radiologist, only after which the data was analyzed and recorded.
Results - All cases (100%) of epidermoid and neuroblastoma showed true diffusion
restriction. 100% GBM cases showed true restricted diffusion while none of the low- grade
tumours showed diffusion restriction. All cases of arachnoid cysts showed low signal on DWI.
And none of benign meningioma and schwannoma showed restriction diffusion. Positive
correlation was found in the comparison of mean ADC values for high-grade gliomas
(1.02×10-3 mm2/s±0.2) and metastasis (0.881×10-3 mm2/s±0.2), low-grade gliomas (1.20 ×
10-3 mm2/s ± 0.2), and medulloblastomas (2.09×10-3 mm2/s ± 0.075).
Conclusion - Presence of diffusion restriction is a useful method of differentiating abscesses
from necrotic or cystic neoplasms. Highly cellular tumors may show restricted diffusion.
Arachnoid cysts can be differentiated from epidermoid cysts by presence of low signal on
DWI. ADC is useful in the differentiation of various brain mass lesions and in grading brain
tumours. The combination of routine image interpretation and ADC had a higher diagnostic
predictive value in characterizing brain lesions.