Sensitivity and specificity of "mini brain" image pattern to diagnose multiple myeloma and plasmacytoma

Abstract

Introduction: "Mini brain" image pattern has been identified as a radiological sign for diagnosing multiple myeloma (MM) and solitary plasmacytomas in magnetic resonance imaging (MRI). However, there is still very little data on the frequency with which it can be observed, and its real diagnostic accuracy. Objetive: In this study, we present our case series, discuss sensitivity and specificity of "mini brain" in the diagnosis of multiple myeloma (MM)/plasmacytoma, and conduct a literature review. Methods: The study sample consisted of asymptomatic and/or symptomatic patients consecutively diagnosed with expansive vertebral disease. Patients were evaluated with MRI. A literature review was conducted on the relationship of the radiological sign "mini brain" and the diagnosis of multiple myeloma (MM) or plasmacytoma. Results: Forty-seven patients were evaluated consecutively. Among five patients diagnosed with multiple myeloma, four had an MRI pattern of "mini brain". The sensitivity of "mini brain" was 80%. The specificity was 97.6%. The accuracy was 95.8%. Sensitivity and specificity were 100% when we considered differential diagnoses only with neoplastic lesions involving the spine. Conclusions: "Mini brain" is a feasible and reliable sign for the diagnosis of multiple myeloma/plasmacytoma, guiding physicians for adequate screening and treatment. Nevertheless, it should not replace pathological investigation after vertebral biopsy. Level of Evidence III; Study of case: Case-control study.