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.

摘要
引言：“迷你脑”影像征象已被确定为磁共振成像（Magnetic Resonance Imaging, MRI）中诊断多发性骨髓瘤（Multiple Myeloma, MM）及孤立性浆细胞瘤（solitary plasmacytomas）的放射学指征。然而，目前关于该征象的检出频率及其实际诊断准确性的相关数据仍十分匮乏。
研究目的：本研究通过病例系列分析，探讨“迷你脑”征象在诊断多发性骨髓瘤（MM）/浆细胞瘤中的灵敏度（sensitivity）与特异度（specificity），并开展相关文献综述。
研究方法：本研究纳入连续确诊的伴或不伴症状的膨胀性椎体病变患者，所有受试者均接受磁共振成像检查。同时，我们针对“迷你脑”放射学征象与多发性骨髓瘤（MM）或浆细胞瘤诊断的相关性进行了系统文献综述。
研究结果：本研究共纳入47例连续入组患者。在5例确诊为多发性骨髓瘤的患者中，4例呈现“迷你脑”磁共振成像模式。“迷你脑”征象的灵敏度为80%，特异度为97.6%，诊断准确度为95.8%。若仅将脊柱肿瘤性病变纳入鉴别诊断范畴，其灵敏度与特异度均可达到100%。
研究结论：“迷你脑”征象是诊断多发性骨髓瘤/浆细胞瘤的可靠且可行的影像学指征，可指导临床医师开展针对性筛查与治疗。但需注意，该征象不可替代椎体活检后的病理学检查。证据等级Ⅲ级（Level of Evidence III）；研究类型：病例对照研究（Case-control study）。