Transient peritumoral enhancement during dynamic MRI of the liver: cavernous hemangioma versus hepatocellular carcinoma

PURPOSE: The purpose of this work was to compare the incidence and pattern of transient peritumoral parenchymal enhancement for cavernous hemangioma and hepatocellular carcinoma during dynamic MRI of the liver. METHOD: Two hundred seven hemangiomas and 155 hepatocellular carcinomas up to 4 cm in size were retrospectively assessed. The peritumoral enhancement was comparatively analyzed in terms of the shape, extent, signal intensity, and dependence on the size and degree of contrast enhancement of each tumor. RESULTS: For small lesions (<2 cm), hemangiomas (16/141; 11.3%) showed a higher incidence (p = 0.026) of peritumoral enhancement than hepatocellular carcinomas (3/87; 3.5%). For larger lesions (2-4 cm), there was no significant difference (p > 0.05) in the incidence of peritumoral enhancement of hemangiomas (15/66; 22.7%) and hepatocellular carcinomas (15/68; 22.1%). Nineteen (61.3%) of the 31 hemangiomas showed contrast agent filling the entire tumor volume at the phase of peritumoral enhancement. CONCLUSION: In spite of the limited specificity, for a <2 cm small focal lesion with homogeneous contrast enhancement on early phase dynamic MR images in the liver, peritumoral enhancement could suggest a higher possibility of hemangioma rather than hepatocellular carcinoma.     

Hepatic hemangiomas with arterioportal shunt: sonographic appearances with CT and MRI correlation

OBJECTIVE: The purpose of this study was to summarize and illustrate the sonographic appearance of hepatic hemangiomas with arterioportal shunt and to correlate them with CT and MRI findings. CONCLUSION: High-flow hepatic hemangiomas tend to be seen as hypoechoic lesions at sonography. In the presence of fatty infiltration in the liver, they may accompany peritumoral low-echoic areas presumably caused by peritumoral sparing of fatty infiltration similar to a hyperattenuating or hyperintense peritumoral rim on unenhanced CT or MR chemical shift imaging. Color Doppler sonography may reveal intratumoral flows, large feeding arteries, and reversal of portal flow around the tumor. Knowledge of such sonographic findings may ensure an accurate sonographic diagnosis of these tumors.     

Sparing of fatty infiltration around focal hepatic lesions in patients with hepatic steatosis: sonographic appearance with CT and MRI correlation

OBJECTIVE: The purposes of this study were to illustrate the sonographic features of focal hepatic lesions with peritumoral sparing of fatty infiltration in patients with hepatic steatosis, to correlate the sonographic findings with CT and MRI findings, and to discuss the possible mechanisms. CONCLUSION: Various focal hepatic lesions can accompany peritumoral sparing of fatty infiltration in patients with hepatic steatosis, and they can manifest with an atypical sonographic appearance.     

动态及延时增强磁共振成像对肝血管瘤诊断的评价

目的:研究动态增强及延迟增强扫描磁共振成像对肝血管瘤的诊断价值。材料和方法:34例肝血管瘤病人行常规MRT1WI、T2WI横断面扫描。经肘静脉手推团注0.1mmol/kg体重Gd-DTPA后,再推入10ml生理盐水冲洗后(推入时间5~6s)行射频毁坏傅立叶采集稳态技术T1WI动态增强扫描及延迟增强扫描,分析病灶及邻近肝实质增强。结果:共发现肝血管瘤病灶67个。动态增强见46个病灶呈边缘不连续样的结节样强化,21个病灶呈周边不规则强化或迅速强化充填;5个病灶动态增强早期见引流静脉强化,14个瘤周肝实质强化。延迟增强扫描见53个病灶完全充填强化,14个病灶显示斑片状或裂隙状的低信号未充填区。结论:在磁共振成像检查中,动态增强扫描能够显示肝血管瘤及邻近实质强化方式,延迟增强显示病灶的充填程度,两者结合更有利于肝血管瘤的诊断。     

Temporal peritumoral enhancement of hepatic cavernous hemangioma: findings at multiphase dynamic magnetic resonance imaging

OBJECTIVE: To evaluate the occurrence rate of temporal peritumoral enhancement associated with hepatic cavernous hemangiomas and to correlate that with the speed of intratumoral contrast enhancement and tumor volume. METHODS: Dynamic magnetic resonance imaging (MRI) of 69 consecutive patients with 136 hemangiomas was reviewed for peritumoral enhancement. Tumor volume was estimated by the largest diameter on T2-weighted images. Speed of intratumoral contrast enhancement was determined by portal phase image and was categorized as rapid (>75% of tumor volume), intermediate (25%-75% of tumor volume), or slow (<25% of tumor volume). RESULTS: Temporal peritumoral enhancement was found in 37 (26.6%) of 136 hemangiomas. It was more common in hemangiomas with rapid enhancement (30 of 67 cases [44.8%]) than in those with intermediate (3 of 22 cases [13.6%]) and slow (4 of 47 cases [8.5%]) enhancement (P < 0.05). There was no statistically significant relation between lesion size and presence of temporal peritumoral enhancement (P > 0.05). CONCLUSIONS: Temporal peritumoral enhancement is not uncommonly seen in hepatic cavernous hemangiomas at dynamic MRI. It is most commonly encountered in rapidly enhancing small lesions. There is no statistically significant relation between temporal peritumoral enhancement and tumor volume, however.     

多层动态增强MRI技术对肝血管瘤诊断的评价

目的:研究射频毁坏傅立叶采集稳态技术(RFFAST)的动态增强及延迟增强扫描MRI对肝血管瘤的诊断价值。方法:34例肝血管瘤患者行常规MRT1WI和T2WI横断面扫描。经肘静脉团注GdDTPA0.1mmol/kg,后推入10ml生理盐水冲洗(推入时间5～6s),再行射频毁坏傅立叶采集稳态技术T1WI动态增强扫描及延迟增强扫描,分析病灶及邻近肝实质增强。结果:共发现肝血管瘤病灶67个,T1WI上呈低信号,T2WI上呈高信号;动态增强显示46个病灶呈边缘不连续的结节样强化,21个病灶呈周边不规则强化或迅速强化充填;5个病灶动态增强早期见引流静脉较早强化,14个瘤周肝实质强化。结论:磁共振成像检查中,射频毁坏傅立叶采集稳态技术T1WI动态增强扫描能够显示肝血管瘤及邻近实质强化方式,与其他成像序列结合更有利于肝血管瘤的诊断。     

Hepatic cavernous hemangioma: temporal peritumoral enhancement during multiphase dynamic MR imaging

PURPOSE: To determine whether temporal parenchymal enhancement around hepatic cavernous hemangiomas can be correlated with the rapidity of intratumoral contrast material enhancement and/or tumor volume at dynamic magnetic resonance (MR) imaging. MATERIALS AND METHODS: Dynamic MR images obtained in 94 patients with 167 hemangiomas were retrospectively reviewed for peritumoral enhancement. Tumor volume was estimated by using the longest dimension on nonenhanced images. Speed of intratumoral contrast material enhancement was determined with early nonequilibrium phase images and was categorized as rapid (>75% of tumor volume), intermediate (25%-75% of tumor volume), or slow (<25% of tumor volume). RESULTS: Thirty-two of the 167 hemangiomas (19%) had temporal peritumoral enhancement, which was more common in hemangiomas with rapid enhancement (20 of 49 [41%]) than in those with intermediate (12 of 62 [19%]) and slow (0 of 56 [0%]) enhancement (P: <.001). The mean diameter of the hemangiomas with peritumoral enhancement was not significantly different from that of hemangiomas without peritumoral enhancement (P: >.05). Hemangiomas with rapid enhancement (mean diameter, 16 mm +/- 8), however, were significantly smaller than those with intermediate enhancement (mean diameter, 33 mm +/- 34) (P: <.001). CONCLUSION: Temporal peritumoral enhancement on dynamic MR images of hepatic hemangiomas correlates well with the speed of intratumoral contrast material enhancement and was most commonly encountered in rapidly enhancing small lesions. There was no statistically significant relationship, however, between peritumoral enhancement and tumor volume.     

Fat sparing of surrounding liver from metastasis in patients with fatty liver: MR imaging with histopathologic correlation

OBJECTIVE: The purpose of our study was to evaluate the characteristic MR imaging findings and histopathologic correlation of peritumoral fat sparing of liver metastasis in patients with fatty liver. CONCLUSION: Out-of-phase spoiled gradient-echo MR imaging was useful in detecting and characterizing the peritumoral fat sparing of liver metastasis in patients with fatty liver that was isointense to surrounding hepatic parenchyma on unenhanced in-phase spoiled gradient-echo, T2-weighted inversion recovery, and contrast-enhanced nonsuppressed spoiled gradient-echo MR imaging.     

Fatty metamorphosis in hepatocellular carcinoma: radiologic features in 10 cases

We describe the sonographic, CT and angiographic findings in 10 cases of hepatocellular carcinoma in which extensive fatty metamorphosis occurred within the tumors. Fatty change was diffuse in smaller tumors (less than 3.5 cm) and focal in larger tumors (greater than 3.5 cm). Fatty metamorphosis characteristically caused a low-attenuation area on CT (less than -10 H) and a highly echogenic area on sonography. The sonographic appearance of small hepatocellular carcinomas with fatty metamorphosis was identical to the findings in cavernous hemangioma or focal fatty change of the liver. CT correctly revealed the presence of fat in these hepatocellular carcinomas. In these cases, hepatic arteriography showed no tumor stain; however, CT arteriography (dynamic CT during injection of contrast medium into the hepatic artery) was useful in showing the tumor, its capsule, and its internal septa. In the diagnosis of large hepatocellular carcinoma, the presence of intratumoral fat is not likely to be problematic, but small tumors that are diffusely infiltrated by fat must be distinguished from such benign conditions as focal fatty change, lipoma, and angiomyolipoma.     

Single breath-hold multiarterial dynamic MRI of the liver at 3T using a 3D fat-suppressed keyhole technique

PURPOSE: To evaluate the feasibility of single breath-hold, multiarterial MRI of the liver using the THRIVE-CENTRA-keyhole technique. MATERIALS AND METHODS: Twenty-eight patients with 63 focal hepatic lesions underwent liver MR examinations that included the three-dimensional THRIVE-CENTRA-keyhole sequence. Three or six phases were obtained for arterial phase scanning during a single breath-hold. Central k-space data were collected for each phase but the remaining peripheral k-space data were collected only once. The enhancement pattern of each hepatic lesion was analyzed according to the specific diagnosis. RESULTS: Hepatocellular carcinomas (n = 24) enhancement patterns included: rim enhancing (n = 9), homogeneous (n = 7), nodule-in-nodule (n = 5), or heterogeneous (n = 3). A late peritumoral rim was observed in four (17%) of the hepatocellular carcinomas. Most metastases (17 of 18; 94%) demonstrated peripheral rim enhancement. The progressive centripetal enhancement of hemangiomas (n = 6) was clearly depicted. Focal nodular hyperplasia (n = 4) showed early homogeneous enhancement and one lesion demonstrated a central scar. CONCLUSION: The THRIVE-CENTRA-keyhole technique can be used to acquire single breath-hold, multiarterial images depicting improved enhancement characteristics of focal hepatic lesions. This technique will allow accurate timing of arterial scanning with 3D acquisition and high temporal resolution.     

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.     

肝海绵状血管瘤MRI动态增强表现

目的研究肝脏海绵状血管瘤MRI动态增强表现。材料与方法107例患者行MRI平扫及FL2D或SE序列动态增强扫描,分析其中的119个血管瘤的动态增强表现。结果41个血管瘤在增强早期(团注造影剂后1min内)表现为均一高信号增强,78个血管瘤表现为边缘结节状增强并逐渐向中间充填增强。SE序列扫描1.2％(1/84)的病灶延迟期呈等信号充填增强,FL2D扫描11.5％(4/35)的病灶延迟期呈等信号充填增强,余病灶均表现为高信号充填增强。结论肝血管瘤可归纳为两种增强类型快速充填型和边缘结节增强充填型。少部分血管瘤FL2D序列扫描时病灶可呈等信号充填增强。     

椎管内硬膜外海绵状血管瘤的MR表现

目的 探讨椎管内硬膜外海绵状血管瘤R诊断价值。方法 回顾性分析3例经病理证实的椎管内硬膜外海绵状血管瘤的MR表现，并复习相关文献。结果 3例椎管内硬膜外海绵状血管瘤中，2例位于胸椎，1例位于颈胸椎。3例均沿脊椎纵轴生长，呈梭形或长条形；2例肿块“钳”状包绕，推挤相应水平的脊髓；3例均表现为T2WI高信号，钆喷替酸葡甲胺（Gd-DTPA)增强扫描呈均匀一致的明显强化；2例肿瘤侵犯，压迫相邻的椎间孔并使椎间孔扩大，且经椎间孔突出旁间隙，呈“哑铃状”外观。2例合并椎体血管瘤。结论 椎管内硬膜外海绵状血管是非常少见的椎管硬膜外肿瘤，MRI是诊断此病的最佳方法，并具有相对特征性表现。     

Real-time contrast-enhanced ultrasound imaging of focal liver lesions in fatty liver

PurposeThe objective of this study was to investigate the contrast-enhanced ultrasound (CEUS) imaging features of focal liver lesions (FLLs) in fatty liver.MethodOne hundred FLLs in 98 patients with fatty liver were evaluated with real-time CEUS.ResultsAll malignant FLLs showed hyperenhancement in arterial phase and contrast washout in portal and late phases. Among the FLLs, 3.3% of hemangiomas, 12.5% of focal nodular hyperplasias (FNHs), and 2.5% of focal fatty sparing lesions showed contrast washout in the late phase. The sensitivity and specificity for the characterization of hepatocellular carcinoma, metastasis, hemangioma, FNH, and focal fatty sparing lesions were 100% and 95.6%, 60% and 100%, 93.3% and 98.6%, 87.5% and 97.8%, and 92.6% and 100%, respectively.ConclusionsCorrect characterization of FLLs in fatty liver by CEUS is possible based on their typical enhancement patterns.     

Role of contrast enhanced ultrasound in characterization of focal liver lesions

Aim

The purpose of the study was to describe the enhancement patterns of focal liver lesions (FLLs) on contrast enhanced sonography (CEUS), assessing the potential of this technique for characterizing the lesions and to compare its diagnostic accuracy with conventional baseline sonography including color Doppler.

Materials and methods

Between August 2009 and July 2010, 50 patients with FLLs underwent gray scale sonography, color Doppler and CEUS. The enhancement patterns of these FLL’s were analyzed throughout the arterial phase, the portal venous phase and the extended portal venous phase (the late parenchymal phase). The final diagnosis was established on the basis of histopathologic examination or CT/MRI imaging.

Results

Out of these 50 FLLs, 33 were malignant (4 hepatocellular carcinoma and 29 metastasis) and 17 were benign (5 hemangioma, 5 abscess, 2 cyst and 1 each of FNH, focal fat sparing area, focal fatty infiltration, adenoma and benign/granulomatous lesion). The enhancement patterns after injecting microbubble contrast agent allowed characterization of FLLs. The malignant lesions showed intratumoral and/or peritumoral vascularity during the arterial phase and perfusion defect during the late parenchymal phase. Contrast enhanced sonography improved sensitivity in detecting malignancy (CEUS vs. baseline sonography, 100% vs. 81.8%).

Conclusion

CEUS improves detection and characterization of FLLs. It should be used as problem solving tool in cases where conventional gray scale and color Doppler sonography are non-diagnostic.     

肝血管瘤超声造影表现

目的:探讨肝血管瘤超声造影(contrast enhanced ultrasound,CEUS)的表现。方法:应用对比剂Sonovue及对比脉冲序列成像(contrast pulse sequenuce sound,CPS)技术对25例28个肝血管瘤进行超声造影检查,观察对比剂在动脉期、门脉期及延迟期的增强表现。结果:26个(92.9%)病灶动脉期呈环状增强伴附壁结节或球状突起,门脉期呈缓慢向心性充填,21个病灶呈完全充填,5个病灶呈不完全充填,延迟期与周围肝实质期比呈相对高增强;另2个(7.1%)病灶动脉期、门脉期及延迟期均无增强。结论:超声造影肝血管瘤的典型增强表现为动脉期环状增强,门脉期缓慢向心性充填,延迟期呈高增强。     

Imaging of atypical hemangiomas of the liver with pathologic correlation.

Compared with the imaging features of typical hepatic hemangiomas, the imaging features of atypical hepatic hemangiomas have not been well studied or well described. Knowledge of the entire spectrum of atypical hepatic hemangiomas is important and can help one avoid most diagnostic errors. A frequent type of atypical hepatic hemangioma is a lesion with an echoic border at ultrasonography. Less frequent types are large, heterogeneous hemangiomas; rapidly filling hemangiomas; calcified hemangiomas; hyalinized hemangiomas; cystic or multilocular hemangiomas; hemangiomas with fluid-fluid levels; and pedunculated hemangiomas. Adjacent abnormalities consist of arterial-portal venous shunt, capsular retraction, and surrounding nodular hyperplasia; hemangiomas can also develop in cases of fatty liver infiltration. Associated lesions include multiple hemangiomas, hemangiomatosis, focal nodular hyperplasia, and angiosarcoma. Types of atypical evolution are hemangiomas enlarging over time and hemangiomas appearing during pregnancy. Complications consist of inflammation, Kasabach-Merritt syndrome, intratumoral hemorrhage, hemoperitoneum, volvulus, and compression of adjacent structures. In some cases, such as large heterogeneous hemangiomas, calcified hemangiomas, pedunculated hemangiomas, or hemangiomas developing in diffuse fatty liver, a specific diagnosis can be established with imaging, especially magnetic resonance imaging. However, in other atypical cases, the diagnosis will remain uncertain at imaging, and these cases will require histopathologic examination.     

颅内海绵状血管瘤的CT和MRI诊断

目的 探讨CT和MRI对颅内海绵状血管瘤的表现和诊断价值。资料与方法 经手术病理证实的颅内海绵状血管瘤22例,其中脑内型海绵状血管瘤21例,脑外型海绵状血管瘤1例。10例行CT检查,16例行MRI检查,13例行MRA检查。结果 脑内型海绵状血管瘤可位于脑内任何部位,单发病灶多见,周围无或轻度水肿,无明显占位效应。CT平扫为稍高密度影,钙化占72．7％,增强扫描大都无强化;MR T1WI表现为桑葚状混杂高信号．周围有云絮状低信号环,增强后病灶大都无强化;MRA检查未见异常血管。脑外型病灶位于中颅窝、鞍旁,MRI呈类似哑铃形较均匀的稍长T1、长T2信号,增强扫描见明显均匀强化．MRA检查未见异常血管。结论 脑内型海绵状血管瘤的MRI表现较有特异性,结合CT和MRA可明确诊断;脑外型者易误诊,对CT和MRI表现类似的中颅窝脑膜瘤,应考虑到本病的可能。     

Imaging of hepatic steatosis and fatty sparing

Radiology has gained importance in the non-invasive diagnosis of hepatic steatosis. Ultrasonography is usually the first imaging modality for the evaluation of hepatic steatosis. Unenhanced CT with or without dual kVp measurement and MRI with in and out of phase sequence can allow objective evaluation of hepatic steatosis. However, none of the imaging modalities can differentiate non-alcoholic steatohepatitis/fatty liver disease from simple steatosis. Evaluation of hepatic steatosis is important in donor evaluation before orthotopic liver transplantation and hepatic surgery. Recently, one-stop shop evaluation of potential liver donors has become possible by CT and MRI integrating vascular, parenchymal, volume and steatosis evaluation. Moreover hepatic steatosis (diffuse, multinodular, focal, subcortical, perilesional, intralesional, periportal and perivenular), hypersteatosis and sparing (geographic, nodular and perilesional or peritumoral) can cause diagnostic problems as a pseudotumor particularly in the evaluation of oncology patients. Liver MRI is used as a problem-solving tool in these patients. In this review, we discuss the current role of radiology in diagnosing, quantifying hepatic steatosis and solutions for diagnostic problems associated with fatty infiltration and sparing.     

Noninvasive diagnosis of small cavernous hemangioma of the liver: advantage of MRI

Thirty-three lesions of small cavernous hemangioma of the liver under 3 cm in diameter detected by sonography, computed tomography (CT), or magnetic resonance imaging (MRI) were reviewed. Sonography detected 23 lesions, plain CT 15 out of 26, and MR 31, including one equivocal. On sonography, 18 of 23 revealed a strong, almost homogeneous hyperechoic mass without a rim. On CT, eight of 33 showed characteristic findings of hemangioma by contrast enhancement. On MRI, 26 of 31 appeared as a markedly high-intensity area, which was rarely the appearance of other hepatic tumors of similar size. Spin-spin relaxation time (T2) of hemangioma was prolonged over 80 msec in 15 of 18 while one of 20 lesions in patients with primary or secondary liver cancers under 3 cm showed T2 of 80 msec or more. MRI in addition to sonography and/or CT allowed detection of almost all cavernous hemangiomas over 1 cm in diameter and diagnosis with considerably high accuracy and specificity. MRI will play an important role in determination of necessity of further invasive diagnostic methods for patients with small liver tumors detected by sonography and/or CT.