Departments of Radiology and ENT Surgery, Hospital Universitari í Politècnic La Fé de Valencia, Bulevar Sur s/n, 46026 Valencia, Spain.
Radiographics. 2012 Jul-Aug;32(4):1197-213. doi: 10.1148/rg.324115109.
Middle ear cholesteatoma is a common inflammatory disease that requires surgery due to potentially serious intracranial complications. Diagnosis of cholesteatoma is mainly clinical, with computed tomography (CT) used to evaluate disease extension before surgery. Certain patterns of bone erosion are specific, but CT attenuation does not allow differentiation from other inflammatory middle ear diseases. With its high tissue discrimination and contrast resolution, magnetic resonance imaging is valuable in diagnosis of cholesteatomas. Absent enhancement at delayed postcontrast imaging has been used for diagnosis. Diffusion-weighted imaging (DWI) is highly specific due to the high keratin content of cholesteatomas. New non-echo-planar DWI sequences, such as periodically rotated overlapping parallel lines with enhanced reconstruction, are superior to conventional echo-planar DWI, since they minimize susceptibility artifacts at the skull base and increase sensitivity for detection of lesions as small as 2 mm. This technique is indicated when clinical diagnosis is difficult and high tissue specificity is necessary, as in congenital, temporal bone, or atypical acquired middle ear cholesteatomas and residual or recurrent disease after surgery. Non-echo-planar DWI has been proposed for screening of postsurgical (residual or recurrent) cholesteatomas, thus obviating many second-look revision surgeries, especially after more conservative canal wall up surgery.
中耳胆脂瘤是一种常见的炎症性疾病，由于可能发生严重的颅内并发症，通常需要手术治疗。胆脂瘤的诊断主要基于临床，在手术前，通过计算机断层扫描（CT）评估疾病的扩展情况。某些类型的骨质侵蚀具有特异性，但 CT 衰减并不能将其与其他炎症性中耳疾病区分开来。磁共振成像（MRI）具有很高的组织分辨率和对比分辨率，在胆脂瘤的诊断中具有重要价值。延迟对比后增强扫描无强化可用于诊断胆脂瘤。由于胆脂瘤中含有大量角蛋白，扩散加权成像（DWI）具有很高的特异性。新型非回波平面 DWI 序列，如带增强重建的周期性旋转重叠平行线，优于传统的回波平面 DWI，因为它们可以最大限度地减少颅底的磁化率伪影，并提高对小至 2mm 病变的检测敏感性。在临床诊断困难且需要高组织特异性时，例如先天性、颞骨或非典型获得性中耳胆脂瘤以及手术后的残留或复发性疾病，需要使用这种技术。非回波平面 DWI 已被提议用于手术后（残留或复发）胆脂瘤的筛查，从而避免了许多二次手术，尤其是在更为保守的鼓室成形术之后。
