Multiparametric MRI Evaluation of Ring-Enhancing Lesions at KIMS Hospital, Bengaluru (Code-T0293)

Introduction: Ring-enhancing lesions (RELs) in the brain are commonly encountered on MRI and can result from a variety of etiologies, including infections, neoplasms, inflammatory conditions, and demyelinating diseases. Accurate differentiation of these lesions is critical for appropriate clinical management. Multiparametric MRI, including diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), and magnetic resonance spectroscopy (MRS), offers advanced diagnostic capabilities beyond conventional MRI.

Aims and Objectives

To establish a differential diagnosis and to study the role of advanced Magnetic Resonance Imaging (MRI) techniques such as diffusion-weighted MRI, perfusion-weighted MRI, Magnetic Resonance Spectroscopy (MRS) as additional protocols during diagnostic evaluation of ring enhancing lesions in the essentially normal brain study with objectives of :

1. A) Improvement in lesional detection sensitivity.
2. B) Improvement of specificity in establishing differential diagnosis

Methods: A prospective study was conducted on 43 patients presenting with ring-enhancing brain lesions at a tertiary care center. Patients underwent conventional MRI, along with DWI, PWI, and MRS. Apparent diffusion coefficient (ADC) values, relative cerebral blood volume (rCBV), and metabolic ratios (Cho/Cr, Cho/NAA) were analyzed. Statistical analysis, including ROC curve assessment, was performed to determine the diagnostic accuracy of these imaging techniques.

Results: DWI effectively differentiated infectious from neoplastic lesions, with infectious lesions showing higher ADC values. PWI demonstrated significantly elevated rCBV values in neoplastic lesions compared to infectious ones (p < 0.001). MRS revealed characteristic metabolic peaks, aiding in further differentiation. The combination of these modalities improved diagnostic accuracy, with rCBV showing 95% specificity and 87% sensitivity for neoplastic lesions.

Conclusion: Multiparametric MRI significantly enhances the diagnostic accuracy of ring-enhancing brain lesions, aiding in early and precise differentiation. Incorporating advanced MRI techniques can improve patient management and treatment planning.

Keywords: Ring-enhancing lesions, Multiparametric MRI, Diffusion-weighted imaging, Perfusion-weighted imaging, Magnetic resonance spectroscopy, Neoplastic lesions