Hepatic adenomas and focal nodular hyperplasia: dynamic CT study

A retrospective, multi-institutional study was carried out on a series of 50 histologically proved benign hepatic tumors. The 27 hepatic adenomas (HAs) and 23 cases of focal nodular hyperplasia (FNH) were studied with ultrasonography (US) and dynamic computed tomography (CT). Angiography was performed in 26 cases (15 HAs, 11 FNHs); scintigraphy was not used because of its cost. US scans proved nonspecific. CT scans demonstrated hemorrhage in five HAs and were useful in characterizing tumoral vascularity and any intratumoral features such as necrosis or central fibrous scar. The presence of arterial vessels (five patients) in the projection of this central fibrous scar is suggestive of FNH. Dynamic CT scans did not show the type of tumor in most cases. In cases with lesions greater than 3 cm for which doubt as to the diagnosis persists, combined use of morphologic data, scintigraphy, dynamic CT scanning, and angiography can guide the therapeutic decision: surgery or follow-up CT study after use of oral contraceptives is stopped.     

Hepatic focal nodular hyperplasia: MR imaging at 1.0 and 1.5 T.

Ten cases of hepatic focal nodular hyperplasia (FNH) were studied with magnetic resonance (MR) imaging. Proof of diagnosis was by needle biopsy or follow-up of as long as 5 years. Both short TR/TE and long TR/TE images were obtained. The most common finding was isointensity of the lesion relative to liver parenchyma with all pulse sequences. A central scar was seen in only one patient and was hyperintense on long TR/TE images. Slight hyperintensity of the lesion on short TR/TE and long TR/TE images was seen in two cases. Textural heterogeneity was present in only one of these. The most common presentation in our series was a visually isointense lesion relative to liver on short TR/TE images and an isointense or slightly hyperintense lesion on long TR/TE images. A review of the literature and the present findings suggest that FNH has a variable appearance on MR images.     

Hepatic adenoma: MR appearance mimicking focal nodular hyperplasia

A hepatic adenoma (HA) nearly isointense to normal liver on short and long repetition and echo time spin echo pulse sequences is presented. Contrary to previous expectations, the case shows that a single hepatic mass with these signal characteristics on magnetic resonance without a scar may represent either HA or focal nodular hyperplasia.     

Hepatic adenoma and focal nodular hyperplasia: a diagnostic dilemma

Focal Nodular Hyperplasia (FNH) and Hepatic Adenoma (HA) remain difficult diagnostic problems due to their variable imaging appearances. Five new cases are presented, illustrating this variability, and the current literature is reviewed. Ultrasonography is a sensitive modality for their detection but is otherwise non-specific. On computer tomography, the presence of a scar suggests FNH, whilst haemorrhage suggests HA. However these features are seen in only a small number of cases. Radionuclide (colloid) scanning aids considerably in FNH but a definitive role has not been found in HA. Angiography is helpful, providing anatomical information, sometimes diagnostic (septated blush in FNH, hypovascular areas in HA) and able to discern benign from malignant lesions. Where imaging is not definitively diagnostic, percutaneous biopsy is indicated if FNH is suspected and surgical biopsy if HA is felt likely.     

Telangiectatic focal nodular hyperplasia: US,CT, and MR imaging findings with histopathologic correlation in 13 cases

PURPOSE: To review the ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging findings in 13 patients with telangiectatic focal nodular hyperplasia (FNH) and to compare imaging features with histopathologic results from resected specimens. MATERIALS AND METHODS: US, helical multiphasic CT, and MR images in 13 patients with pathologically proven telangiectatic FNH were reviewed retrospectively. Two abdominal radiologists evaluated lesions for number, size, heterogeneity, surface characteristics, presence of a central scar, presence of a pseudocapsule, US appearance, attenuation at CT, signal intensity at MR imaging, and presence of associated lesions. Imaging and pathologic findings were compared. RESULTS: Sixty-one lesions (5-140 mm in diameter) were seen at imaging. Lesions were multiple in eight of 13 (62%) patients. Imaging characteristics were heterogeneity in 26 of 61 lesions (43%), well-defined margins in 43 of 61 (70%), lack of a central scar in 56 of 61 (92%), presence of a pseudocapsule in three of 61 (5%), hyperintensity on T1-weighted MR images in 17 of 32 (53%), strong hyperintensity on T2-weighted MR images in 24 of 54 (44%), and persistent enhancement on delayed contrast material-enhanced CT or T1-weighted MR images in 23 of 38 (61%). No specific US pattern was noted. Two patients had additional lesions: One had classic FNH, and the other had a cavernous hemangioma. Hyperintensity on T1-weighted MR images was due to sinusoidal dilatation. Hyperintensity on T2-weighted MR images correlated well with the presence of inflammation. CONCLUSION: Telangiectatic FNH differs from typical FNH at imaging: Atypical FNH features often observed with telangiectatic FNH are lack of a central scar, lesion heterogeneity, hyperintensity on T1-weighted MR images, strong hyperintensity on T2-weighted MR images, and persistent contrast enhancement on delayed contrast-enhanced CT or T1-weighted MR images.     

Pediatric focal xanthogranulomatous pyelonephritis: dynamic contrast-enhanced MRI findings

Xanthogranulomatous pyelonephritis (XPN) is the result of chronic renal infection. It is very rare in childhood and the focal form, which is said to be more common in children, is often misdiagnosed as a renal tumor. We report a case of a focal XPN in a 14-year-old girl. The true preoperative diagnosis may be very hard in children especially in the focal form but it seems to be possible by the help of dynamic contrast-enhanced MRI.     

Hepatic focal nodular hyperplasia: diagnosis by ultrafast Gd-DTPA enhanced FLASH MR

The utility of gadolinium-enhanced ultrafast MR imaging in the diagnosis of focal nodular hyperplasia (FNH) of the liver was assessed in one patient. Contrast-enhanced serial snapshot-FLASH with a frequency of 30 images/min demonstrated the typical hemodynamic appearance of FNH known from CT studies.     

Differential diagnosis of focal nodular hyperplasia with quantitative parametric analysis in contrast-enhanced sonography

OBJECTIVES: We investigated the potential of quantitative parametric analysis in the differential diagnosis of focal nodular hyperplasia (FNH) from other hypervascularized liver focal lesions. MATERIALS AND METHODS: Eighty-five focal liver lesions (in 83 patients) were explored using contrast-enhanced ultrasound (SonoVue and Cadence Contrast Pulse Sequencing) consisting of typical FNH (n=52), hepatocellular carcinoma (n=11), hemangioma with high flow (n=8), hypervascular metastases (n=10), and hepatocellular adenoma (n=4). QontraXt software (AMID, Italy) was used here to estimate the following parameters: maximum peak value, Tr (time corresponding to time for obtaining 63% of the plateau), beta parameter corresponding to the exponential factor, and slope corresponding to the tangent value of the first phase of enhancement. These parameters were obtained from the time-intensity curves derived from the enhancement observed in 2 regions of interest corresponding, respectively, to the whole lesion and the central region only. RESULTS: A significant statistical difference (P<0.05) was found in the values of Tr, beta, and slope between FNH and other hypervascularized lesions on both the whole lesion and central region. Among these parameters, slope appeared as the most valuable whatever the region of interest, ie, central or whole lesion (P<0.01). Central region was more accurate in the differentiation of FNH and concordant with visual characterization. CONCLUSION: Quantitative parametric curve analysis of the different hypervascularized lesions confirms the depiction of the central artery in FNH and thus could help in differentiating this specific focal liver lesion from the others.     

Differentiation of focal nodular hyperplasia and hepatocellular adenoma by contrast-enhanced ultrasound

Non-invasive differentiation of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) is difficult. The aim of this study was to assess the accuracy of contrast-enhanced phase inversion ultrasound to differentiate between histologically proven FNH and HCA, analysing the arterial and (early) portal venous phase. 32 patients with histological proven FNH (n=24) or HCA (n=8) have been included in this prospective study. Examination technique: Siemens Elegra, phase inversion harmonic imaging (PIHI) with low mechanical index (MI)<0.2-0.3 using SonoVue (BR 1). The contrast enhancing tumour characteristics were evaluated during the hepatic arterial (starting 8-22 s) and early portal venous phase (starting 12-30 s). The image analysis was performed by three examiners. In 23 of 24 patients with FNH the contrast pattern revealed pronounced arterial and (early) portal venous enhancement. Homogeneous enhancement was detected during the hepatic arterial phase in all eight patients with HCA. In contrast to patients with FNH, no enhancement was seen during the portal venous phase. In conclusion, contrast-enhanced phase inversion ultrasound demonstrated pronounced arterial and portal venous enhancement in patients with focal nodular hyperplasia. In contrast, after homogeneous enhancement during hepatic arterial phase, no enhancement during hepatic portal venous phase was detected in patients with hepatocellular adenoma. Therefore, this technique might improve the functional characterization of benign hypervascular focal liver lesions.     

Scintigraphic findings mimicking focal nodular hyperplasia in a case of hepatoblastoma.

Hepatoblastoma is a primary liver neoplasm in which prompt diagnosis and resection are critical to long-term survival. Liver scintigraphy using Tc-99m sulfur colloid and Tc-99m iminodiacetic acid (IDA) derivatives has been used in the evaluation of hepatic masses. Most space-occupying lesions of the liver appear as photopenic regions following either Tc-99m SC or IDA agents. Two exceptions have been reported. Focal nodular hyperplasia (FNH) has been shown to have variable colloid uptake, which is dependent upon the number of Kupffer cells per given volume. Many patients with FNH will demonstrate activity within the FNH to be greater or equal to the normal liver. In addition, two cases of hepatoblastoma have been reported to show colloid activity within the tumor, and in one patient slight uptake of Tc-99m IDA was noted in the tumor 15 minutes postinjection. The current case demonstrates a hepatoblastoma in which the scintigraphic findings with Tc-99m SC and Tc-99m IDA were similar to those reported, with retention of IDA far greater than the previously reported case.     

Quantitative analysis of contrast-enhanced ultrasonography: differentiating focal nodular hyperplasia from hepatocellular carcinoma

Objective:

To explore the potential of quantitative analysis of contrast-enhanced ultrasonography (CEUS) in differentiating focal nodular hyperplasia (FNH) from hepatocellular carcinoma (HCC).

Methods:

34 cases of FNH and 66 cases of HCC (all lesions <5 cm) were studied using CEUS to evaluate enhancement patterns and using analytic software Sonoliver® (Image-Arena™ v.4.0, TomTec Imaging Systems, Munich, Germany) to obtain quantitative features of CEUS in the region of interest. The quantitative features of maximum of intensity (IMAX), rise slope (RS), rise time (RT) and time to peak (TTP) were compared between the two groups and applied to further characterise both FNH and HCC with hypoenhancing patterns in the late phase on CEUS.

Results:

The sensitivity and specificity of CEUS for diagnosis of FNH were 67.6% and 93.9%, respectively. For quantitative analysis, IMAX and RS in FNHs were significantly higher than those in HCCs (p<0.05), while RT and TTP in FNHs were significantly shorter (p<0.05). Both the 11 FNHs and 62 HCCs with hypo-enhancing patterns in the late phase were further characterised with their quantitative features, and the sensitivity and specificity of IMAX for diagnosis of FNH were 90.9% and 43.5%, RS 81.8% and 80.6%, RT 90.9% and 71.0%, and TTP 90.9% and 71.0%, respectively.

Conclusion:

The quantitative features of CEUS in FNH and HCC were significantly different, and they could further differentiate FNH from HCC following conventional CEUS.

Advances in knowledge:

Our findings suggest that quantitative analysis of CEUS can improve the accuracy of differentiating FNH from HCC.Dynamic contrast-enhanced ultrasonography (CEUS) has noticeably improved the detection and characterisation of focal liver lesions during the past decade [1]. The enhancement patterns of the lesion are evaluated in three vascular phases (the hepatic arterial, portal venous and late phases), where the hepatic arterial phase provides information on the degree and pattern of vascularity and the portal venous and late phases provide important information on the differention between benign and malignant liver lesions [1]. A previous study has shown that CEUS using SonoVue® (Bracco, Milan, Italy) and spiral-CT provides similar diagnostic accuracy in the characterisation of focal liver lesions [2].The typical enhancement of focal nodular hyperplasia (FNH) on CEUS showed hyperenhancement in the three vascular phases with a stellate vascular and centrifugal enhancement in the arterial phase or a hypoenhancing central scar in the late phase [1, 3–5]. However, these features have not been observed in all cases of FNH, particularly in small lesions. A study on FNH showed that 3 out of 13 lesions (23.1%) were hypoenhancing in the late phase [6] and 3 out of 10 lesions <3 cm had spoke-wheel patterns and 2 had central scars [4]. There is also a broad variation of stellate vascular enhancement in FNHs with a range from 27.3% to 73.3% and of central scar with a range from 36.4% to 63.3% [3–5]. Thus, it can be difficult to differentiate atypical FNHs from other hypervascular malignant tumours, such as hepatocellular carcinoma (HCC), and hypervascular metastases [3]. Furthermore, a hypoenhancing central scar has been described in fibrolamellar HCC and sclerosing or scirrhous HCC [7, 8], and a central feeding artery with spoke-wheel sign has also been described in two scirrhous HCCs [8]. Hence, a comprehensive approache rather than simply estimating the haemodynamics could be beneficial for differential diagnosis.The current low-mechanical-index techniques for CEUS are capable of real-time demonstration of continuous haemodynamic changes in both the liver and hepatocellular nodules, from which time–intensity curves can be obtained by means of analytic software and then a series of semi-quantitative perfusion measurements extracted and analysed [9–11]. This method has shown a possible benefit in diagnosing FNH by enabling analysis of the quantitative parametric curves of the five types of hypervascular liver lesions [9]. In the present study, CEUS was applied to evaluate enhancing patterns of FNH and HCC; quantitative features of CEUS in the two groups were generated with the analytic software Sonoliver® (TomTec Imaging Systems, Germany) and compared to explore their potential in the differential diagnosis. Furthermore, the quantitative analysis of CEUS was used to characterise both FNH and HCC with hypoenhancing patterns in the late phase on CEUS.     

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     

肝脏巨大局灶性结节增生伴囊变MRI表现一例

患者男,41岁.体枪发现肝脏占位性病变1周入院.体检无明显异常.外院B超提示"肝右叶占位性病变".实验室检查:碱件磷酸酶(ALP):5.1 μmol·s-1/L,γ-谷氨酰转肽酶(γ-GT):123 U/L,均升高,余指标如甲胎蛋白(AFP)、癌胚抗原(CEA)和糖类抗原19-9(CA19-9)均正常.     

肝脏局灶性结节增生的CT及MRI表现

目的:探讨肝局灶性结节增生(FNH)的螺旋CT及高场强MRI的影像学表现,提高FNH诊断准确率.方法:回顾性分析60例经手术病理证实的66个FNH.螺旋CT检查32例,MRI检查30例,其中2例同时做了CT和MRI.结果:CT发现33个病灶,MRI发现35个病灶,其中平扫中CT31个为均匀的低或稍低密度,2个为等密度,T1WI30个为低或稍低信号,5个为等信号,T2WI均呈高或稍高信号.病灶中心见点状,星状,裂隙状更低密度/信号:CT11个,T1WI16个,T2WI19个为更高信号.动脉期所有病灶均明显强化,病灶中心更低密度/信号区均未强化,病灶周围有增粗,扭曲血管影:CT7个,MRI10个.门脉期呈高或稍高密度/信号:CT21个,MRI33个.呈等密度/信号:CT10个,MRI2个.呈稍低密度:CT2个.病灶中心更低密度/信号强化:CT1个,MRI6个.延迟期呈高或稍高密度/信号:CT4个,MRI30个.呈等密度/信号:CT24个,MRI5个.呈稍低密度:CT5个.病灶中心更低密度/信号强化:CT10个,MRI15个.结论:平扫和动态增强螺旋CT及高场强MRI能较全面显示FNH的病理特征和血供特点,提高了和其它肝脏肿瘤的鉴别诊断能力.     

肝脏多发局灶性结节性增生的MRI诊断

目的 评估MR诊断肝脏多发局灶性结节性增生(focal nodular hyperplasia,FNH)的价值.方法 回顾性分析经病理证实的9例多发FNH的MR表现,并与部分病灶病理所见对照.结果 9例诊断均考虑到FNH的可能性,5例第一诊断考虑为FNH,3例第一诊断考虑为肝腺瘤,1例第一诊断考虑为纤维板层型肝癌.9例共31个病灶,T2WI 19个呈稍高信号、12个呈等信号;T1WI上12个呈稍低信号、7个呈等信号、12个呈高信号;反相位成像1个病灶局部信号略有减低.注射Gd-DTPA后,动脉期18个病灶轻度至明显不均匀强化、11个病灶显著均匀强化、1个病灶中度不均匀环形强化、1个病灶未见异常强化;门静脉期和延迟期31个病灶均逐渐呈等信号或稍高信号.共16个病灶出现中央瘢痕,瘢痕延迟期强化.结论 多发FNH有特征性表现,大部分病例MR能正确诊断.     

Contrast-enhanced ultrasound features of histologically proven focal nodular hyperplasia: diagnostic performance compared with contrast-enhanced CT

Objectives

To investigate and compare contrast-enhanced ultrasound (CEUS) in the characterisation of histologically proven focal nodular hyperplasia (FNH) with contrast-enhanced computed tomography (CECT).

Methods

CEUS was performed in 85 patients with 85 histologically proven FNHs. Enhancement, centrifugal filling, spoke-wheel arteries, feeding artery and central scarring were reviewed and correlated with lesion size or liver background. Independent factors for predicting FNH from other focal liver lesions (FLLs) were evaluated. Forty-seven FLLs with CECT were randomly selected for comparison of diagnostic performance with CEUS.

Results

Centrifugal filling was more common (P?=?0.002) and the significant predictor (P?=?0.003) in FNHs ≤3 cm. Lesion size or liver background has no significant influence on the detection rate of the spoke-wheel arteries and feeding artery (P?>?0.05). Central scarring was found in 42.6 % of FNHs ≥3 cm (P?=?0.000). The area under the ROC curve, sensitivity and specificity showed no significant differences between CEUS and CECT (P?>?0.05), except that the sensitivity of CEUS was better for reader 1 (P?=?0.041).

Conclusion

CEUS is valuable in characterising centrifugal filling signs or spoke wheels in small FNHs and should be employed as the first-line imaging technique for diagnosis of FNH.

Key Points

? The confident diagnosis of focal nodular hyperplasia is important in liver imaging. ? The centrifugal filling sign is useful for diagnosis of FNHs ≤3 cm. ? Contrast-enhanced ultrasound and contrast-enhanced CT have similar diagnostic performance for FNH. ? CEUS should be the first-line imaging technique for the diagnosis of FNH.