Early-stage focal nodular hyperplasia: US/CT/MR features correlated with histology

Two cases of local nodular hyperplasia (FNH), in which ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MR) studies detected an atypical hemorrhagic pattern associated with an intrahepatic arterio venous malformation (AVM) around the growths, are presented. In both cases, histology demonstrated a very early regenerative stage — without central scar or fibrosis — and necrotichemorrhagic areas within the lesions. In these cases, the analysis of radiological findings, surgical specimens and histology seemed to confirm the pathogenetic hypothesis suggested by Wanless [1]: in normal liver parenchyma, a blood steal phenomenon due to congenital or acquired intrahepatic AVM — arterio portal or porto systemic shunt — could cause ischemic damaged, appering as a hemorrhagic necrotic area, the extent of which depends on the degree of residual portal supply (maintained in Case 1, and markedly reduced in Case 2 due to arterio portal shunting). The subsequent phase of repair could activate the regenerative-hyperplastic process, evolving into final fibrosis, which represents the mature pattern of FHN. Correspondence to: R. Golfieri     

Focal nodular hyperplasia: imaging findings

Focal nodular hyperplasia is an uncommon benign hepatic tumor that continues to pose diagnostic dilemmas. Imaging techniques are of great value in diagnosis of this tumor. In this article we present the US, CT, MR imaging, scintigraphy, and angiography findings. The demonstration of a central vascular scar is very helpful. Although the radiologic features may be diagnostic, many atypical cases must be differentiated from other benign or malignant hepatic tumors. In these cases excisional biopsy and histopathologic examination are necessary to determine a definite diagnosis. Received: 7 March 2000/Revised: 13 June 2000/Accepted: 15 June 2000     

Ferumoxides and Tc-99m sulfur colloid: Comparison of the tumor-to-liver uptake in focal nodular hyperplasia

The tumor-to-liver uptake of two reticuloendothelial agents, namely ferumoxides and technetium-99m (Tc-99m) sulfur colloid, was compared in focal nodular hyperplasia (FNH). Twelve patients with FNH who had undergone ferumoxides-enhanced MR imaging and planar Tc-99m sulfur colloid scintigraphy within 1 year were included from the study. Fourteen patients with FNH with a diameter larger than 3 cm were selected for the comparison. The tumor-to-liver ferumoxides uptake was calculated and the Tc-99m sulfur colloid uptake was assessed visually. Ferumoxides uptake was observed in all but one patient with FNH (mean tumor-to-liver ratio = .36). The six tumors showing normal (n = 5) or increased (n = 1) radiocolloid uptake when compared to the liver accumulated more ferumoxides than the eight tumors showing decreased radiocolloid uptake (P < .01). However, in some tumors, no direct relation was observed between ferumoxides and Tc-99m sulfur colloid uptake. Our observations suggest that ferumoxides uptake might not exactly mimic Tc-99m sulfur colloid uptake in FNH.     

Nonspecificity of the fat-sparing ring surrounding focal liver lesion at MR imaging

RATIONALE AND OBJECTIVES: The presence of a fat-sparing ring surrounding focal liver lesions in patients with steatosis has been described only in malignant lesions. Our purpose is to evaluate whether this fat-sparing ring peripheral to tumors is a specific marker of malignancy. MATERIALS AND METHODS: From 300 magnetic resonance examinations of focal liver lesions, 132 patients with a confirmed nature of the lesions were selected. There were 24 patients (18.2%) with lesions having a perilesional fat-sparing ring in the opposed-phase spoiled T1-weighted gradient echo images. All these livers had steatosis. RESULTS: Perilesional fat-sparing rings were observed in 19 (21.6%) malignant and 5 (11.4%) benign lesions. Size of the lesion was not related to the presence of the fat-sparing ring (P=.6), neither was type of lesion (malignant versus benign) statistically related to the presence of the perilesional fat-sparing ring in the opposed-phase gradient echo magnetic resonance images (chi-square, P=.15). Fat-sparing rings were mainly seen in metastases (51.4% of metastases), but seldom in primary malignant tumors (1.9% of hepatocellular carcinomas). Hemangiomas also presented this finding (18.5% of hemangiomas). CONCLUSIONS: We believe that the presence of this bright rim surrounding lesions on oppose-phase images in patients with steatosis mainly represent decrease portal flow, either because of compressed and atrophic hepatocyte cords with sinusoidal congestion in expanding metastatic lesions or the presence of arterioportal perfusion abnormalities in vascularized hemangiomas.     

Focal nodular hyperplasia: intraindividual comparison of dynamic gadobenate dimeglumine- and ferucarbotran-enhanced magnetic resonance imaging

PURPOSE: To intraindividually compare the enhancement pattern of focal nodular hyperplasia (FNH) after dynamic administration of two bolus-injectable liver-specific MR contrast agents, ferucarbotran and gadobenate dimeglumine. MATERIALS AND METHODS: A total of 19 patients with 24 FNHs underwent gadobenate dimeglumine- and ferucarbotran-enhanced MRI during the hepatic arterial-dominant phase (HAP; 25 seconds), the portal-venous phase (PVP; 60 seconds), and the equilibrium phase (EP; 180 seconds). Hepatospecific phases were acquired on T1-weighted images 120 minutes after gadobenate dimeglumine administration, and on T2-weighted images 10 minutes after ferucarbotran administration. Lesion enhancement was independently analyzed by two observers. The kappa statistic was determined to evaluate the agreement between the enhancement patterns of the lesions. RESULTS: On gadobenate dimeglumine-enhanced MR images during HAP, PVP, and EP, FNHs were: hyperintense (24/20/13); isointense (0/4/11); and hypointense (0/0/0). On ferucarbotran-enhanced MR images during HAP, PVP, and EP, FNHs were: hyperintense (2/0/0); isointense (16/9/14); and hypointense (6/15/10). Overall, poor agreement between both contrast agents was observed. During the hepatospecific phases, most (20/24; 83%) FNHs showed a typical enhancement pattern during the delayed hepatospecific phase. CONCLUSION: The dynamic enhancement pattern of FNHs is significantly different between gadobenate dimeglumine- and ferucarbotran-enhanced MRI. With respect to hepatospecific phase, the majority of FNHs showed a typical behavior on both contrast agents.     

儿童肝脏局灶性结节增生临床表现与影像学表现关联分析

目的：探讨儿童肝脏局灶性结节增生（FNH）的影像表现,提高对该病影像学特征的认识。方法：回顾性分析6例经病理证实为 FNH 的患儿临床及影像学资料,其中3例患儿发病前确诊患有神经母细胞瘤、急性淋巴细胞白血病和髓母细胞瘤,另外3例患儿无恶性病变病史,均系偶然发现。3例患儿行 MRI 检查,2例患儿行 CT 检查,1例患者行 CT及 MRI 检查,行 CT 检查者全部行增强扫描,2例行 MRI 增强扫描。结果：6例诊断为 FNH 患儿中3例（男2例,女1例,平均年龄8．7岁）存在远隔脏器恶性病变病史,影像学上3例患儿肝脏均呈多发病变,病变最大径2．0～5．2 cm,边界尚清楚,1例可见纤维分隔及中心瘢痕,1例可见引流静脉。其他3例 FNH 患儿（男1例,女2例,平均年龄7．3岁）无恶性病变病史,2例呈单发病变,1例呈多发病变;病变最大径4．3～7．6 cm,边界清楚,2例可见纤维分隔及中心瘢痕,3例均无明确引流静脉显示。结论：增强 CT 及 MRI 检查,尤其是 MSCT 血管成像能真实反映儿童 FNH 的病理学特点及血液动力学改变,对儿童肝脏 FNH 患者影像学特点的认知和了解对于该病的鉴别诊断及临床治疗具有重要意义。     

Focal nodular hyperplasia of the liver on ferumoxides-enhanced MR imaging: features on conventional spin-echo, fast spin-echo and gradient-echo pulse sequences

The aim of this study was to assess the efficacy of a superparamagnetic iron oxide, ferumoxides, in the detection and characterization of focal nodular hyperplasia (FNH) on MR conventional spin-echo (SE), fast spin-echo (FSE) and gradient-echo (GRE) images. Fourteen adults with 27 FNHs were evaluated at 1.5 T before and after injection of ferumoxides. T1-weighted and T2-weighted SE, T2-weighted FSE and T2^*-weighted GRE sequences were used and analysed qualitatively and quantitatively. One hundred percent of FNHs showed a significant postcontrast decrease in signal intensity on T2- and T2*-weighted images. Heavily T2-weighted SE images showed the maximum decrease in FNH signal-to-noise ratio (S/N). Postcontrast GRE T2^*-weighted images improved the detection of the central scar and the delineation of FNHs and demonstrated the best lesion-to-liver contrast-to-noise ratio (C/N). Postcontrast T1-weighted SE images showed the least lesion-to-liver C/N. Ferumoxides-enhanced MR imaging can help detect and characterize FNH. Conventional pre- and postcontrast T2-weighted SE images and postcontrast GRE T2*-weighted images should be used preferentially. Received: 30 November 1998; Revised: 5 April 1999; Accepted: 6 April 1999     

肝脏局灶性结节增生的CT和DSA诊断

 目的 探讨CT和DSA对肝脏局灶性结节增生(focal nodular hyperplasia, FNH)的诊断价值。方法 收集武警四川总队医院2008-06至2016-08经病理证实的5例FNH患者的CT和数字减影血管造影(digital subtraction angiography,DSA)图像,结合文献对其临床、病理和影像表现进行回顾性分析。CT为平扫加多期增强扫描,DSA检查为选择性肝动脉造影。结果 5例均为单发肿块,CT平扫均呈密度不均、边界较清的稍低密度肿块影;增强扫描动脉期病灶均明显强化,其中心为条状或放射状无强化瘢痕影;门脉期病灶呈等密度改变,中心低密度瘢痕影无强化;延迟扫描低密度瘢痕逐渐强化。DSA中病灶表现为富血供占位,供血动脉迂曲、增粗,进入病灶后呈放射状分布显示,染色均匀,境界清楚。结论 FNH的CT多期扫描和DSA表现具有一定的特征性,二者结合对其诊断与鉴别诊断极有价值。     

肝局灶性结节状增生的临床病理学观察

目的观察肝局灶性结节状增生(FNH)的临床及病理学特点。方法收集解放军总医院1989年2月-2010年10月手术切除的FNH标本36例,均经4%甲醛溶液固定,石蜡包埋切片,行HE染色及CD34、CK免疫组化染色(SP法),光镜下观察其组织病理形态。结果 36例患者中男10例,女26例,平均年龄36.1岁;34例呈单发结节,2例呈多发结节;结节直径1.7~20.0cm,平均6.8cm;临床及影像学缺少特异性表现。组织形态学观察显示36例FNH中6例为血管扩张型,25例为经典型,3例为混合型,2例为肝细胞不典型增生型。病理学表现为结节状肿块,中央为纤维性瘢痕,其内为大小不等厚壁血管。免疫组化染色CD34及CK均呈阳性。经典型FNH具有4种特征性形态学表现,即肿瘤结节中央有星状瘢痕、异常结节状结构、畸形血管和毛细胆管增生。结论 FNH的病因可能与病灶处局部血液循环障碍有关。     

MSCT多期增强扫描对肝脏局灶性结节增生的诊断价值

目的:探讨MSCT多期增强扫描对肝脏局灶性结节增生(focal nodular hyperplasia,FNH)的诊断价值。方法:回顾性分析经手术及穿刺活检病理证实的9例FNH患者10个病灶的MSCT多期增强扫描表现。结果:9例中8例为单发病灶,1例多发。平扫9个呈低或稍低密度,1个等密度。平扫3个病灶见中央瘢痕;多期增强扫描7个病灶见中央瘢痕,动脉期及门脉期瘢痕均未见强化,延迟期5个见中央瘢痕强化。增强扫描动脉期除中央瘢痕外,8个FNH病灶明显均匀强化,2个中等均匀强化;门脉期病灶密度下降,但均略高于或等于正常肝实质;延迟期病灶密度等于或略低于肝实质。动脉期4个病灶中心或周边见增粗的供血动脉,其中1个为肝动脉分支直接进入病灶中心,1个的供血动脉自病灶中心沿纤维间隔向周边呈放射状分布,另2个周边见供血动脉。结论:MSCT多期扫描可反映病灶的血供特点和病理学特征,对FNH具有重要的诊断及鉴别诊断价值。     

肝脏局灶性结节增生

肝脏局灶性结节增生(FNH)不是真正的肿瘤。病理学上FNH是正常的肝细胞对先天性或获得性异常血管的反应性增生．病变中主要包括异常血管、正常的肝细胞、Knffer细胞、胆管及增生的纤维结缔组织。CT检查中典型表现为动脉及门静脉早期明显均匀增强的多血管性肿块．并且病变中心出现延迟强化的中心瘢痕。典型的MRI表现包括等或略长T1及等或略长T2信号．中心瘢痕呈明显的长Tl长T2信号．SPIO增强有助于病变的诊断。     

肝脏局灶性结节增生的典型与非典型MR表现及其病理基础

目的:研究肝脏局灶性结节增生(FNH)的典型与非典型MR表现及其病理基础,探讨MRI对各型的诊断价值。方法:分析经手术病理证实的FNH 28例(36个病灶)的典型与非典型MR表现,并与病理结果相对照。结果:①典型表现20例(28个病灶),大小在2.0~10.5cm,T1WI上呈等/稍低信号,T2WI上呈等/稍高信号,增强扫描动、门脉期病变呈显著增强,延迟扫描呈等/略高信号,中心瘢痕出现率占42.9%(12/28例),于T1WI上呈低信号,T2WI上呈高信号,增强扫描呈延迟强化。组织学上有特征性的中央纤维瘢痕,由纤维结缔组织和扭曲的血管组成,并向外放射状形成许多纤维间隔,纤维间隔旁围绕以无明显异形性的肝细胞形成硬化样结节;②非典型表现8例(8个病灶),大小在1.5~8.5cm,T1WI呈略高或低信号,T2WI呈不均匀高信号,增强扫描病灶强化不显著、不均匀,病灶内未见中心瘢痕或瘢痕不强化,出现假包膜等。镜下病变内毛细胆管扩张,其内纤维分隔较短、不连续,部分较大病灶内有出血、脂肪变及坏死,但无异型性肝细胞。结论:MRI能很好反映肝脏局灶性结节增生的典型与非典型表现的病理基础,具有高度的诊断特异性。     

Monitoring of laser and freezing-induced ablation in the liver with T1-weighted MR imaging.

During both interstitial laser ablation therapy and cryoablation therapy for liver tumors, real-time monitoring is necessary for assessment of ongoing thermal effects in tissue. With single-section images obtained every 30 seconds with a T1-weighted RARE (rapid acquisition with relaxation enhancement) sequence, signal intensity changes in both ex vivo and in vivo animal liver were readily seen. The reversible loss of signal intensity that took place during laser irradiation and the increased intensity at the beginning of cooling can be explained mainly by altered T1 due to temperature change. The frozen area was seen as a sudden decrease in signal intensity at 0 degrees C due to a T2 decrease. This preliminary work showed that the protocol provides enough temporal and temperature resolution to accurately depict the extent of thermal damage, as confirmed at histologic examination. Signal intensity decreased linearly with temperature in the range 10 degrees C-50 degrees C, yielding a pixel-to-pixel temperature resolution of 5.37 degrees C.     

Differentiation of hepatocellular adenoma and focal nodular hyperplasia of the liver: comparison of power Doppler imaging and conventional color Doppler sonography

The aim of our study was to compare the diagnostic efficacy of power Doppler imaging and conventional color Doppler sonography for differentiating between hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH) of the liver. Thirty-one focal liver lesions (in 29 patients) with histologic proof of HCA (n = 9) or FNH (n = 22) were studied with power and color Doppler sonography according to a standardized examination protocol. The size of the lesions ranged between 1.5 and 14.5 cm (HCA, 3.5–14.5 cm, mean ± SD 7.3 ± 3.3 cm; FNH, 1.5–9.1 cm, mean ± SD 5.1 ± 2.1 cm). Intratumoral vessels with a venous Doppler spectrum, associated with either pulsatile or continuous peripheral flow, were detected in HCA (eight of nine lesions by power Doppler imaging and six of nine by color Doppler imaging) but not in FNH. In contrast, color signals with an arterial Doppler spectrum, radiating from the center to the periphery of the lesion, were depicted in FNH (20 of 22 cases by power Doppler imaging and 15 of 22 by color Doppler sonography) but not in HCA. Differentiation of HCA and FNH was achieved in 28 of 31 cases (90 %) by power Doppler imaging and in 21 of 31 (68 %) by color Doppler sonography (p < 0.01). Power Doppler imaging is superior to conventional color Doppler sonography in the depiction of the intratumoral flow characteristics of HCA and FNH, and enables a more accurate differential diagnosis than color Doppler sonography. Received 13 January 1997; Revision received 24 February 1997; Accepted 28 March 1997     

肝脏局灶性结节增生CT诊断

目的:提高对肝脏局灶性结节增生(FNH)CT表现的认识和术前诊断准确性。方法:回顾性分析6例经手术病理确诊FNH病例的典型和不典型CT表现。结果:6例FNH病例中,4例具有较典型的CT表现:如显示中心疤痕(3例);增强早期明显均匀强化(除外疤痕)(4例);增粗与扭曲的供血动脉(3例)等。另外2例,增强早期明显不均匀强化;疤痕区不明显等,术前被误诊为肝细胞肝癌。结论:通过对典型和不典型FNH病例的平扫和增强CT分析,有助于提高对FNH的CT征象的认识,从而提高FNH术前诊断的准确性。     

肝脏局灶性结节增生的CT多期扫描表现及病理对照研究

目的：评价多层螺旋CT（MSCT）多期扫描对肝脏局灶性结节增生的临床诊断价值。方法回顾性分析12例经病理确诊为肝脏局灶性结节增生的患者,对其MSCT的平扫、动脉期、门脉期及延迟期共4期扫描图像进行分析,并与病理结果进行对照研究。结果本组12例病例男女比例为7∶5,年龄20~65岁,平均年龄34岁。12例患者均进行CT四期扫描,共观察到病灶12个,病灶位于肝脏左外叶2个,左内叶3个,右前叶4个,右后叶3个,最大平面直径范围为1．7~4．8 cm,平均（3．1±1．3）cm。病灶CT平扫呈等密度5个,低密度7个,等密度者无法显示病灶边缘,低密度者2例病灶边界清楚,5例病灶边界显示模糊,其中可见更低密度瘢痕组织3例。CT增强动脉期显示12例病灶均呈明显强化,其中5例可见中央瘢痕或条索状低密度影,中间瘢痕组织无强化,11例病灶边界显示清晰,均未见包膜;门脉期病灶较动脉期密度降低,但仍较肝脏组织密度高,中间瘢痕组织无明显强化,仍呈低密度;延迟期病灶呈等密度为主,瘢痕组织可见强化,与病灶呈等密度分辨不清。结论MSCT多期扫描在肝脏局灶性结节增生的影像表现方面有一定的特征性,在诊断及鉴别诊断中有很好的作用,但确诊还需要病理诊断。     

Characterization of hepatic adenoma and focal nodular hyperplasia with gadoxetic acid

Purpose:

To characterize imaging features of histologically proven hepatic adenoma (HA) as well as histologically and/or radiologically proven focal nodular hyperplasia (FNH) using delayed hepatobiliary MR imaging with 0.05 mmol/kg gadoxetic acid.

Materials and Methods:

Five patients with six HAs with histological correlation were retrospectively identified on liver MRI studies performed with gadoxetic acid, and T1‐weighted imaging acquired during the delayed hepatobiliary phase. Additionally, 23 patients with 34 radiologically diagnosed FNH lesions (interpreted without consideration of delayed imaging) were identified, two of which also had histological confirmation. Signal intensity ratios relative to adjacent liver were measured on selected imaging sequences.

Results:

All six hepatic adenomas (100%), which had histological confirmation, demonstrated hypointensity relative to adjacent liver on delayed imaging. Furthermore, all of the FNH (including 34 radiologically proven, 2 of which were also histologically proven) were either hyperintense (23/34, 68%) or isointense (11/34, 32%) relative to the adjacent liver on delayed imaging. None of the FNHs were hypointense relative to liver.

Conclusion:

Distinct imaging characteristics of HA versus FNH on delayed gadoxetic acid‐enhanced MRI, with adenomas being hypointense and FNH being iso‐ or hyperintense on delayed imaging may improve specificity for characterization, and aid in the differentiation of these two lesions. J. Magn. Reson. Imaging 2012;36:686–696. © 2012 Wiley Periodicals, Inc.     

肝脏局灶性结节增生的螺旋CT诊断

目的探讨肝脏局灶性结节增生的螺旋CT影像表现,旨在提高对该病的诊断准确性。方法经手术病理证实的肝脏局灶性结节增生19例均经螺旋CT平扫与增强扫描,对其影像特征回顾性分析。结果肝脏局灶性结节增生多发生于青壮年患者,主要分布在肝脏表面,病变边界清晰,动态增强肝动脉期病灶总体显著强化,病灶内见点状、小星状、大片放射状低密度中央瘢痕影,其中大片放射状中央瘢痕延时扫描可见轻度-中度强化。结论螺旋CT动态增强扫描对肝脏局灶性结节增生的定性诊断有较高价值。     

Differentiation between hemangiomas and cysts of the liver with nonenhanced MR imaging: Efficacy of T2 values at 1.5 T

The authors studied the utility of non-contrast-agent-enhanced magnetic resonance (MR) imaging for differentiating cysts and cavernous hemangiomas of the liver. Nineteen patients with hemangiomas (51 lesions) and 16 with cysts (30 lesions) were studied with a 1.5-T MR imager. T2 values were calculated with the two-point method to evaluate the efficacy of T2 values in the differentiation between hemangiomas and cysts of the liver. For lesions larger than 1 cm, the mean T2 value of cysts (306 msec ± 156) was significantly longer than that of hemangiomas (113 msec ± 15) (P < .0001); there was no overlap of the ranges for T2 values of hemangiomas and cysts. All cysts larger than 1 cm could be differentiated from hemangiomas by using a threshold T2 value of 140 msec. This study suggests that calculated T2 values permit differentiation between hemangiomas and cysts larger than 1 cm at 1.5 T.     

肝脏局灶性结节增生影像分析

目的 :分析肝脏局灶性结节增生 (FNH )的CT、MR及DSA表现 ,提高对本病的认识。方法 :6例经证实的FNH ,均行CT、MR及DSA检查。结果 :6例病灶CT平扫低密度者 4例 ,均匀或不均匀 ,2例为等密度。增强动脉期所有病灶均有明显强化 ,除中心瘢痕外病灶强化均匀一致 ,3例可见到中心或周边增粗、扭曲的动脉。门脉期和延迟期扫描 4例病灶为等密度 ,2例为略高密度。 3例伴有中心瘢痕 ,1例无强化 ,2例延迟强化。 2例行DSA检查 ,病灶内分布较均匀的新生血管团。MR检查 4例 ,T1 WI呈等信号或略低信号 ,T2 WI呈略高信号。 1例行Gd DTPA增强延迟期呈略高信号 ,中心瘢痕无明显强化。结论 :CT、MR及DSA检查可充分反映FNH的血供特点和病理特征 ,动态增强是诊断FNH最有效的影像学手段 ,在诊断和鉴别诊断中具有很大价值