Role of In-vivo Proton Magnetic Resonance Spectroscopy (PMRS) and Diffusion Weighted Imaging (DWI) in the Differential Diagnosis of Intracranial Cystic Mass Lesions

D. Jha, A. M. Mishra, R. S. Jaggi, S. Chawla, M. Agarwal, N. Husain, M. Husain, K. Prasad, R. K. Gupta Neurosurgery, King George Medical University, Lucknow, Uttar Pradesh, India, Dept of Radiodiagnosis, SGPGIMS, Lucknow, Uttar Pradesh, India, Pathology, King George Medical University, Lucknow, Uttar Pradesh, India, Microbiology, SGPGIMS, Lucknow, Uttar Pradesh, India Synopsis: We studied fifty-five patients of cystic intracranial lesions, which include abscesses (n=25), benign cysts (n=5) and tumor cysts (n=25) by diffusion weighted imaging (DWI) and proton MR spectroscopy (PMRS). Results were conclusive in 18/25 cases of abscesses on DWI whereas PMRS was conclusive in all but one. When both techniques were combined, the results were conclusive in all the patients with abscesses. DWI was conclusive in 19 tumor cysts and 5 benign cysts whereas PMRS was conclusive in remaining 6 cases of tumor cysts. When PMRS is combined with DWI, it helps in better differentiation of cystic brain lesions Introduction: Intracranial cystic mass lesions make a significant part of neurosurgical problems. The management of these cystic lesions depends upon its nature and it varies from definite surgery (cystic glioma) to minimal invasion (abscesses, arachnoid cyst). Conventional contrast enhanced computed tomography (CECT) and magnetic resonance (MR) imaging might not always be sufficient to reach a definitive diagnosis. In the last few years non-invasive techniques like proton MR spectroscopy (PMRS) and diffusion weighted imaging (DWI) are being increasingly used as a tool for diagnosis of intracranial lesions. PMRS has been found to be useful in differentiating various cystic intracranial lesions (1). Cystic intracranial lesions include true cysts lined by epithelial, ependymal, or meningothelial cells, dermoid and epidermoid cysts, parasitic cysts (cysticercosis, hydatid cysts) or may be pseudocystic neoplastic or inflammatory lesions secondary to accumulation of necrotic, intercellular mixed or proteinaceous material. DWI is considered useful in differentiating cystic gliomas from cerebral abscesses (2) and there are no reports of its use in differentiation in other types of cystic lesions. This study was carried out to evaluate the diagnostic efficacy of PMRS and DWI in cases of intracranial cystic mass lesions.