Department of Radiology, Kingston Health Sciences Centre, 76 Stuart Street Kingston, ON, K7L 2V7, Canada.
Joint Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto, ON, M5G 2N2, Canada.
Clin Radiol. 2021 Jan;76(1):75.e13-75.e26. doi: 10.1016/j.crad.2020.06.022. Epub 2020 Jul 22.
The perinephric space is the middle compartment of the retroperitoneum, containing the kidneys and adrenal glands. Differential considerations for diseases involving primarily the perinephric space differ from those arising from the kidney itself, show variant imaging features, and require identification and characterisation by interpreting radiologists-an imaging diagnosis can be suggested in many cases. Lymphangiomas are congenital cystic lesions that may contain lipid-laden chyle, which may be detectable on magnetic resonance imaging (MRI). Retroperitoneal fibrosis, Erdheim-Chester disease, and lymphoma may present as a perinephric soft tissue rind. Osseous findings favour Erdheim-Chester, ureteric obstruction favours retroperitoneal fibrosis, and associated lymphadenopathy with mass-effect, but without invasion of adjacent structures favours lymphoma. Extramedullary haematopoiesis and brown fat stimulation are both characterised by signal drop on opposed-phase T1-weighted (W) images, the former resulting from severe anaemia and the latter in the context of elevated serum catecholamines, especially in the setting of phaeochromocytoma. Liposarcoma is the most common primary sarcoma of the retroperitoneum. Metastases are uncommon; however, they can be seen in melanoma, among other primary malignancies. Increased T1W signal hyperintensity is typical of melanoma metastases and haematomas. Abscesses show non-enhancing fluid centrally with marked diffusion restriction. This article presents a review of the perinephric space, pathological conditions of the perinephric space, and an approach towards imaging and diagnosis using cross-sectional imaging, with emphasis on MRI. MRI provides better tissue characterisation, assessment of enhancement kinetics, and detection of intralesional fat in comparison to CT. Clinical and laboratory correlation or tissue sampling may be required for definitive diagnosis in some cases.
肾周间隙是腹膜后腔的中间部分，包含肾脏和肾上腺。主要涉及肾周间隙的疾病的鉴别考虑因素与源于肾脏本身的疾病不同，具有不同的影像学特征，需要由解释放射科医生来识别和描述——在许多情况下可以提出影像学诊断。淋巴管瘤是先天性囊性病变，可能含有富含脂质的乳糜，在磁共振成像（MRI）上可能检测到。腹膜后纤维化、Erdheim-Chester 病和淋巴瘤可能表现为肾周软组织包绕。骨的发现有利于 Erdheim-Chester 病，输尿管梗阻有利于腹膜后纤维化，而伴有肿块效应的相关淋巴结病，但无邻近结构侵犯则有利于淋巴瘤。骨髓外造血和棕色脂肪刺激均表现为反相位 T1 加权（W）图像上的信号下降，前者由严重贫血引起，后者在血清儿茶酚胺升高的情况下发生，尤其是在嗜铬细胞瘤的情况下。脂肪肉瘤是腹膜后最常见的原发性肉瘤。转移瘤不常见；然而，它们可以见于黑色素瘤等原发性恶性肿瘤。黑色素瘤转移瘤和血肿的 T1W 信号强度增加是典型的。脓肿在中央呈无增强液性，弥散受限明显。本文回顾了肾周间隙、肾周间隙的病理状况，以及使用横断面成像进行成像和诊断的方法，重点是 MRI。与 CT 相比，MRI 提供了更好的组织特征、增强动力学评估和对肿瘤内脂肪的检测。在某些情况下，可能需要临床和实验室相关性或组织采样以进行明确诊断。
