【双语病例】Hepatic fungal abscesses 真菌性肝脓肿MR一例

History

57-year-old woman with a history of PBC status post cadaveric liver transplantation 5 years ago

57岁女性,原发性胆汁性肝硬化,尸体肝脏移植术后5年

*PBC:英文缩写很多,小编能查到最合理的就是primary biliary cirrhosis,原发性胆汁性肝硬化。

Fig 2.10.1 T2WI脂肪抑制:

【双语病例】Hepatic fungal abscesses 真菌性肝脓肿一例

Fig 2.10.2 DWI(b=100 s/mm2):

【双语病例】Hepatic fungal abscesses 真菌性肝脓肿一例

Fig 2.10.3 3D SPGR增强扫描门脉期:

【双语病例】Hepatic fungal abscesses 真菌性肝脓肿一例

Imaging Findings

Axial fat-suppressed T2-weighted FSE (Figure 2.10.1) and axial diffusion-weighted (b=100 s/mm2) (Figure 2.10.2) images demonstrate diffuse,small hyperintense nodules throughout the liver. Axial portal venous phase postgadolinium 3D SPGR images (Figure 2.10.3) reveal rim enhancement of the nodules.

横断位T2WI脂肪抑制FSE序列及DWI(b=100 s/mm2) 序列示:肝内多发小结节状高信号,呈散在弥漫分布。

3D SPGR增强扫描门静脉期图像示肝内结节呈环形强化。

Diagnosis

Hepatic fungal abscesses

真菌性肝脓肿

Comment

Hepatic fungal abscesses typically occur in immunocompromised patients who have had episodes of neutropenia.

真菌性肝脓肿一般发生于中性粒细胞减少、免疫功能低下的患者。

The classic appearance of fungal hepatic infection on MRI is micro abscesses—multiple small foci with high T2-signal intensity. Several variations of this theme have been described in the literature, likely corresponding to different phases of the disease.

In the acute setting, T2-weighted images (or diffusion-weighted images)demonstrate small foci of high signal intensity. Many patients also have transfusional hemosiderosis, and therefore the contrast between the small hyperintense abscesses and the dark background liver is accentuated. In the acute phase, postgadolinium images may be somewhat less sensitive than T2-weighted images when the immune response has not yet been sufficient to generate noticeable rim enhancement. In the subacute phase, rim enhancement becomes more prominent on post gadolinium SPGR images, with persistent hyperintensity on T2-weighted images. Many authors have described a rim of dark signal surrounding the central abscess on all imaging sequences, and this is thought to represent iron-containing macro phages accumulating around the periphery of the abscess (iron storage is in their job description as members of the reticuloendothelial system). This finding is not universally present (it’s not seen in this patient,for example) but can be quite impressive, as illustrated by Case 2.11.

肝脏真菌感染的典型MR表现为小脓肿,即多发T2WI高信号的小结节。现有文献中已经报道了该病的几种变化,可能与病变的不同时期有关。

在病变的急性期,T2WI或DWI表现为多发高信号结节状。相当一部分患者有输血引起的含铁血黄素沉着,所以高信号的结节灶和低信号的肝实质背景对比非常明显。急性期,免疫反应尚不充分,增强扫描没有明显的环形强化,所以敏感性相对不如T2WI。

病变的亚急性期,病灶于T2WI仍表现为高信号,增强扫描可见明显的环形强化。部分文献报道,在MR所有序列,均可见中心脓液周边可见环形低信号影,可能与脓液周围含铁的噬菌体沉积有关,这一观点尚未被广泛认可,但给人印象十分深刻。

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