Clinical Efficacy of Multiparametric Magnetic Resonance Imaging and Proton Spectroscopy in the Evaluation of Complex Ring-Enhancing Intracranial Lesions: A Four-Case Series from Pacific International Hospital, Papua New Guinea

Background: Ring-enhancing lesions (RELs) remain a persistent diagnostic challenge in neuroradiology, as neoplastic, infectious, and granulomatous processes frequently overlap in their conventional MRI appearance. Accurate differentiation is critical for guiding management, particularly in resource-limited settings such as Papua New Guinea (PNG), where access to advanced neuroimaging is concentrated in a few centers and specialist manpower is limited. Study setting and design: This retrospective case series was conducted at Pacific International Hospital (PIH), Port Moresby, PNG, over four months (June–September 2026). Four brain MRI cases were included: three presenting as ring-enhancing masses, and one miscellaneous nerve sheath tumour at the craniocervical junction and C1–C2 level. Materials and methods: Of the four cases, two were referred from Port Moresby General Hospital and two were managed in-house at PIH. Conventional MRI sequences, supplemented by single-voxel MR spectroscopy (MRS) in selected cases, were used to evaluate metabolite profiles and to help differentiate primary brain tumour, metastatic disease, and infective processes such as tuberculoma. Results: One case, an 18-year-old male, demonstrated a cortical high-grade glioma with elevated choline-to-N-acetylaspartate (Cho/NAA >1.5) and choline-to-creatine (Cho/Cr >2) ratios, favouring a glial neoplasm despite an atypical age. A second case, a 29-year-old male with constitutional symptoms, showed multifocal ring-enhancing lesions with a preserved NAA peak and Cho/NAA <1, consistent with CNS tuberculoma and correlating with the clinical history. A third case demonstrated periventricular, splenial, and parieto-occipital rim-enhancing and serpentine lesions, radiologically indistinguishable between tuberculoma and neurosarcoidosis; tuberculoma was favoured on supporting clinical evidence. A fourth, miscellaneous case demonstrated a craniocervical/C1–C2 nerve sheath tumour with a characteristic dumbbell configuration on T2-FLAIR and post-contrast T1-weighted imaging. Conclusion: This first PNG-based series demonstrates the added diagnostic value of MRS in characterising ring-enhancing lesions and illustrates how strengthened referral pathways from provincial and district-level facilities to centres equipped with advanced imaging can accelerate diagnosis and improve management outcomes.