Hepatic focal nodular hyperplasia in children:Imaging features on multi-slice computed tomography

AIM:To retrospectively analyze the imaging features of hepatic focal nodular hyperplasia(FNH) in children on dynamic contrast-enhanced multi-slice computed tomography(MSCT) and computed tomography angiography(CTA) images.METHODS:From September 1999 to April 2012,a total of 218 cases of hepatic FNH were confirmed by either surgical resection or biopsy in the Sun Yat-sen Memorial Hospital of Sun Yat-sen University and the Cancer center of Sun Yat-sen University,including 12 cases(5.5%) of FNH in children(age ≤ 18 years old).All the 12 pediatric patients underwent MSCT.We retrospectively analyzed the imaging features of FNH lesions,including the number,location,size,margin,density of FNH demonstrated on pre-contrast and contrastenhanced computed tomography(CT) scanning,central scar,fibrous septa,pseudocapsule,the morphology of the feeding arteries and the presence of draining vessels(portal vein or hepatic vein).RESULTS:All the 12 pediatric cases of FNH had solitary lesion.The maximum diameter of the lesions was 4.0-12.9 cm,with an average diameter of 5.5 ± 2.5 cm.The majority of the FNH lesions(10/12,83.3%) had well-defined margins.Central scar(10/12,83.3%) and fibrous septa(11/12,91.7%) were commonly found in children with FNH.Central scar was either isodense(n = 7) or hypodense(n = 3) on pre-contrast CT images and showed progressive enhancement in 8 cases in the equilibrium phase.Fibrous septa were linear hypodense areas in the arterial phase and isodense in the portal and equilibrium phases.Pseudocapsule was very rare(1/12,8.3%) in pediatric FNH.With the exception of central scars and fibrous septa within the lesions,all 12 cases of pediatric FNH were homogenously enhanced on the contrast-enhanced CT images,significantly hyperdense in the arterial phase(12/12,100.0%),and isodense in the portal venous phase(7/12,58.3%) and equilibrium phase(11/12,91.7%).Central feeding arteries inside the tumors were observed on CTA images for all 12 cases of FNH,whereas no neovascularization of malignant tumors was noted.In 9 cases(75.0%),there was a spoke-wheel shaped centrifugal blood supply inside the tumors.The draining hepatic vein was detected in 8 cases of pediatric FNH.However,the draining vessels in the other 4 cases could not be detected.No associated hepatic adenoma or hemangioma was observed in the livers of the 12 pediatric cases.CONCLUSION:The characteristic imaging appearances of MSCT and CTA may reflect the pathological and hemodynamic features of pediatric FNH.Dynamic multi-phase MSCT and CTA imaging is an effective method for diagnosing FNH in children.

Hepatic pseudolesions caused by alterations in intrahepatic hemodynamics

Hepatic pseudolesion may occur in contrast-enhanced computed tomography and magnetic resonance imaging due to the unique haemodynamic characteristics of the liver.The concept of hepatic arterial buffer response(HABR)has become mainstream for the understanding of the mechanism of the reciprocal effect between hepatic arterial and portal venous flow.And HABR is thought to be significantly related to the occurrence of the abnormal imaging findings on arterial phase of contrast enhanced images,such as hepatic arterial-portal vein shunt and transient hepatic attenuation difference,which mimic hypervascular tumor and may cause clinical problems.Third inflow to the liver also cause hepatic pseudolesion,and some of the cases may show histopathologic change such as focal hyperplasia,focal fatty liver,and focal sparing of fatty liver,and called pseudotumor.To understand these phenomena might be valuable for interpreting the liver imaging findings.

Liver involvement in patients with COVID-19 infection:A comprehensive overview of diagnostic imaging features

During the first wave of the pandemic,coronavirus disease 2019(COVID-19)infection has been considered mainly as a pulmonary infection.However,different clinical and radiological manifestations were observed over time,including involvement of abdominal organs.Nowadays,the liver is considered one of the main affected abdominal organs.Hepatic involvement may be caused by either a direct damage by the virus or an indirect damage related to COVID-19 induced thrombosis or to the use of different drugs.After clinical assessment,radiology plays a key role in the evaluation of liver involvement.Ultrasonography(US),computed tomography(CT)and magnetic resonance imaging(MRI)may be used to evaluate liver involvement.US is widely available and it is considered the first-line technique to assess liver involvement in COVID-19 infection,in particular liver steatosis and portal-vein thrombosis.CT and MRI are used as second-and third-line techniques,respectively,considering their higher sensitivity and specificity compared to US for assessment of both parenchyma and vascularization.This review aims to the spectrum of COVID-19 liver involvement and the most common imaging features of COVID-19 liver damage.

弥漫型脂肪肝内局灶性病变的CT诊断

目的研究在弥漫型脂肪肝背景下肝局灶性病变的CT特征,以提高对其诊断的准确率。资料与方法回顾性分析40例弥漫型脂肪肝合并局灶性病变(35例)或残存肝岛(5例)患者的CT资料,观察脂肪肝对肝局灶性病变CT表现的影响。结果40例弥漫型脂肪肝中,26例合并多发局灶性肝病变,9例合并单发病变,5例残存肝岛。35例肝局灶性病变中,转移瘤18例,肝细胞癌(HCC)术后复发2例,血管瘤8例,多发囊肿5例,多发腺瘤及单发局灶性结节增生(FNH)各1例。CT平扫肝局灶性病变相对密度随脂肪肝程度而异,边界多不清,增强后强化方式则与无脂肪肝背景的肝内病变相似。结论弥漫型脂肪肝内局灶性病变,其CT表现与正常背景下有所差异,增强检查尤其是动态增强对病变的诊断与鉴别具有重要意义;对不典型病例,随访对比有助于正确诊断。

脂肪肝背景下肝局灶性病变检出率的比较影像学研究

目的比较超声(US)、CT、MRI在脂肪肝背景下肝局灶性病变的检出率。方法回顾性分析129例同时做过US、CT、MRI的肝局灶性病变患者的影像表现,以临床影像综合诊断为参考标准,将其分为脂肪肝组(41例)和非脂肪肝组(88例),以比较两组分别用US、CT、MRI 3种检查方法对肝内局灶性病变数目的检出率。结果US对脂肪肝组和非脂肪肝组肝局灶性病变的检出率分别为52.50%、70.97%(P=0.003);CT对两组病变的检出率分别为70%、85.71%(P=0.002);MRI对两组病变的检出率分别为88.75%、87.56%(P=0.780)。结论MRI对肝局灶性病变的检出率最高且不受脂肪肝背景的影响,而US和CT在脂肪肝背景下对肝脏局灶性病变的检出率均受到影响。