Comacchio F, D'Eredità R, Bison E, Chierichetti F, Ferlin G, Marchiori C
Istituto di Clinica Otorinolaringoiatrica, Università di Padova.
Acta Otorhinolaryngol Ital. 1993 Nov-Dec;13(6):517-24.
Necrotizing external otitis (NEO), or malignant external otitis, a severe penetrating infection of the ear canal and the temporal bone, which occurs almost exclusively in diabetic or immunodepressed elderly patients, is caused in most cases by Pseudomonas aeruginosa while Staphylococcus epidermidis and Aspergillus fumigatus have been described as other possible agents. Recently bone scintigraphy, carried out above all employing SPECT, has been considered an important tool in diagnosis and follow-up of NEO. Many Authors confirm the role taken by Technetium99m-methylene-diphosphonate (MDP) and Gallium67-citrate bone scanning. Benecke suggested that response to therapy could be monitored with Ga67 or In111 scans. Two cases of NEO in which diagnosis and follow-up were made using Tc99m-nanocolloid (NC) SPECT are presented in this paper. The Authors discuss the advantages of this latter radiotracer, compared to those obtained with Ga67-citrate, in the follow-up evaluation of therapy efficacy. Tc99m-NC, in fact, is a better inflammation index in that its fixation on bone tissue is determined by the permeability of the basal membrane of vessels. Furthermore, with Tc99m-NC antibiotic therapy may be continued as long as necessary. Bone scintigraphy with other radiotracers may infact result positive for a long period after disease remission in that their fixation is linked to the one remodelling process.
坏死性外耳道炎（NEO），又称恶性外耳道炎，是一种严重的耳道和颞骨深部感染，几乎仅发生于糖尿病或免疫功能低下的老年患者，多数情况下由铜绿假单胞菌引起，而表皮葡萄球菌和烟曲霉也被描述为其他可能的病原体。近来，尤其是采用单光子发射计算机断层扫描（SPECT）进行的骨闪烁显像，已被视为NEO诊断和随访的重要工具。许多作者证实了锝99m-亚甲基二膦酸盐（MDP）和枸橼酸镓67骨扫描所起的作用。贝内克认为可用镓67或铟111扫描监测治疗反应。本文介绍了两例使用锝99m-纳米胶体（NC）SPECT进行诊断和随访的NEO病例。作者讨论了与枸橼酸镓67相比，后一种放射性示踪剂在治疗效果随访评估中的优势。事实上，锝99m-NC是更好的炎症指标，因为其在骨组织上的沉积取决于血管基底膜的通透性。此外，使用锝99m-NC时，抗生素治疗可根据需要持续进行。而使用其他放射性示踪剂进行骨闪烁显像时，由于其沉积与骨重塑过程相关，在疾病缓解后很长一段时间内可能仍呈阳性。
