Characterization of focal liver lesions with a new ultrasound contrast agent using continuous low acoustic power imaging: comparison with contrast enhanced spiral CT

PURPOSE: To evaluate the concordance of the enhancement patterns of a new ultrasound contrast agent (SonoVue) with those obtained with dual-phase contrast-enhanced spiral CT (CE-CT) in the characterization of focal liver lesions (FLLs). MATERIALS AND METHODS: Sixty-two patients with focal liver lesions discovered at ultrasound and also studied with CECT underwent contrast-enhanced ultrasound using continuous low acoustic power imaging after receiving a 2.4 ml bolus of the new US contrast agent SonoVue, consisting of a dispersion of sulphur hexafluoride microbubbles. The examinations were made using ATL HDI-5000, Acuson SEQUOIA and Aloka 5500 Prosound ultrasound systems with 5.2 MHz curved-array probes. The concordance between US and CE-CT images was evaluated on site by two radiologists blinded to CT RESULTS: The FLLs were assessed in the arterial (20 s after CM injection), portal (after 45-60 s) and late (after 120 s) phases for: 1) presence/absence of enhancement 2) distribution of enhancement (homogenous or target distribution, centripetal or centrifugal flow, and other), 3) qualitative enhancement pattern (hyperechoic, hypoechoic, or isoechoic) versus normal liver parenchyma. RESULTS: The concordance between SonoVue-enhanced US and CE-CT was 85%. Moreover during portal venous phase with CEUS it was possible to differentiate between malignancy or benignity of 91% of lesions. CONCLUSIONS: The preliminary data obtained in this study suggest that continuous low acoustic power imaging and contrast-enhanced US show similar results to CT in contrast distribution and contrast enhancement patterns.     

Focal Hepatic Lesions: Evaluation with Contrast-Enhanced Gray-Scale Harmonic US

Objective

To determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization.

Materials and Methods

The study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed.

Results

At vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase.

Conclusion

At contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.     

Evaluation of hepatocellular carcinoma using SonoVue,a second generation ultrasound contrast agent: correlation with cellular differentiation

The appearance of hepatocellular carcinoma (HCC) with contrast-enhanced ultrasound (CEUS) in the vascular phase is described and evaluated as to whether the enhancement pattern correlates with the degree of cellular differentiation. One hundred four HCCs were prospectively evaluated with CEUS using coherent-contrast imaging (CCI) and SonoVue with a low mechanical index (<0.2). The enhancement of HCCs in the vascular phase was analyzed according to the degree of pathological differentiation obtained by fine-needle biopsy. In the arterial phase, all HCCs except for four well differentiated ones (96.2%) showed enhancement (P<0.05). Histological differentiation of hypoechoic lesions in the early portal phase (7 HCCs; 16%) significantly differed from hyperechoic (1 HCC; 1%) or isoechoic lesions (87 HCCs; 83.6%) (P<0.05), with a significant probability of a worse differentiation in hypoechoic lesions. Histological differentiation of isoechoic lesions in the late phase (30 HCCs; 28.8%) significantly differed from hypoechoic lesions (74 HCCs; 71.2%) (P<0.05), with a significant probability of a better differentiation in isoechoic lesions. CEUS using CCI and SonoVue revealed enhancement in the arterial phase in >95% of HCCs, with a few well-differentiated cases not being diagnosed due to the absence of enhancement. Echogenicity in the portal and late phases correlated with cellular differentiation.     

Characterization of focal hepatic lesions in cirrhotic patients by Pulse Inversion Harmonic Imaging US contrast specific technique with Levovist

PURPOSE: To evaluate the capabilities of Pulse Inversion Harmonic Imaging (PIHI) with hepatospecific US contrast agent Levovist in the characterization of focal liver lesions in cirrhotic patients. MATERIALS AND METHODS: Thirty-nine focal hepatic lesions in 25 consecutive cirrhotic patients identified by conventional ultrasound (US), were evaluated by color Doppler (CD), power Doppler (PD) with spectral analysis of tumoural vessels and PIHI. PIHI was performed 30 seconds (vascular phase) and 3-5 minutes (late phase) after Levovist injection. To definitely characterize the evaluated focal hepatic lesions, helical-CT (HCT) enhancement patterns (15 patients) and/or surgical/bioptic histologic findings (10 patients) were considered as reference procedures. RESULTS: Thirty focal hepatic lesions classified as hepatocellular carcinoma (HCC) by reference procedures appeared hypoechoic (n=19), isoechoic (n=5) or hyperechoic (n=6) on conventional US, with basket arterial pattern (n=10), vessels within the tumor (n=6), peripheral arterial pattern (n=4) or no vascular pattern (n=10) on CD/PD evaluation. On PIHI they appeared hyperechoic (n=26) or isoechoic (n=4) in the vascular phase, if compared to the surrounding liver parenchyma, and hypoechoic (n=23) or isoechoic (n=7) in the late phase. Four focal hepatic lesions classified as regenerative nodules (RNs) by reference procedures appeared hypoechoic on conventional US, with peripheral venous/arterial pattern (n=1) or no vascular pattern (n=3) on CD/PD. On PIHI they appeared hypoechoic (n=3) or isoechoic (n=1) in the vascular phase, remaining prevalently hypoechoic (n=3) or isoechoic (n=1) in the late phase. Five focal hepatic lesions classified as hemangioma by reference procedures appeared hyperechoic (n=4) or hypoechoic (n=1) on conventional US with few peripheral venous vessels on CD/PD. On PIHI they revealed progressive fill-in from the periphery toward the centre during the vascular and late phase after Levovist injection. CONCLUSIONS: PIHI seems to be a reliable technique to characterize focal lesions in cirrhotic patients.     

US characterization of focal hepatic lesions with intermittent high-acoustic-power mode and contrast material

RATIONALE AND OBJECTIVES: This study was performed to determine whether ultrasound (US) performed with SonoVue, a contrast agent that contains microbubbles filled with sulfur hexafluoride vapor, depicts differential patterns of contrast enhancement in focal hepatic lesions. MATERIALS AND METHODS: Forty focal hepatic lesions (15 hepatocellular carcinomas [HCCs], 10 metastases, 11 hemangiomas, and four focal nodular hyperplasias) in 39 patients were evaluated by means of US, color Doppler US, and contrast-enhanced US performed by using intermittent high-acoustic-power mode. Contrast-enhanced helical computed tomography (11 patients) and US-guided fine needle aspiration (28 patients) were used as reference procedures. Contrast enhancement patterns were defined by means of both subjective and objective analysis, and baseline and contrast-enhanced US scans were reviewed offline. RESULTS: Thirteen of 15 HCCs, eight of 10 metastases, and all four hemangiomas with an atypical pattern at baseline US were correctly characterized after SonoVue injection. Two of 15 HCCs and two of 10 metastases remained indeterminate, with no characteristic baseline or contrast-enhanced patterns identified. Baseline US was essential in characterizing all hemangiomas with a typical pattern (n = 7), and color Doppler US with spectral analysis of tumoral vessels was essential in characterizing focal nodular hyperplasia. The percentage of diagnostic agreement with reference procedures was significantly increased (P < .001) for contrast-enhanced US compared with baseline US. CONCLUSION: Characteristic patterns of US contrast enhancement with SonoVue help in characterizing and differentiating focal hepatic lesions.     

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.     

平扫和动态增强MRI诊断肝脏局灶性结节增生

目的 探讨肝脏避灶性结节增生（ＦＮＨ）的平扫和动态增强的ＭＲＩ表现及诊断价值。方法 回顾分析２２例２２个手术病理证实的肝脏ＦＮＨ的平扫及动态增强ＭＲＩ资料。结果 病灶平均大小为４．０５ｃｍ,４个病灶在Ｔ１ＷＩ及Ｔ２ＷＩ上呈典型等信号肿块,１８个为不典型信号肿块。８个在平扫ＭＲ上显示中央瘢痕。２１个病灶的实质部分在增强后动脉期呈明显均匀强化,在门脉期及延迟期呈等强化或强于肝实质。２个病灶在门脉期和延     

Characterization of focal liver lesions with contrast-specific US modes and a sulfur hexafluoride-filled microbubble contrast agent: diagnostic performance and confidence

PURPOSE: To assess whether characterization of solid focal liver lesions could be improved by using ultrasonographic (US) contrast-specific modes after sulfur hexafluoride-filled microbubble contrast agent injection, as compared with lesion characterization achieved with preliminary baseline US. MATERIALS AND METHODS: Four hundred fifty-two solid focal hepatic lesions that were considered indeterminate at baseline gray-scale and color Doppler US were examined after microbubble contrast agent injection performed by using low-acoustic-power contrast-specific modes during the arterial (10-40 seconds after injection), portal venous (50-90 seconds after injection), and late (100-300 seconds after injection) phases. Two readers independently and retrospectively reviewed baseline and contrast material-enhanced US scans and classified each depicted lesion as malignant or benign according to standard diagnostic criteria. Sensitivity, specificity, accuracy, and positive and negative predictive values and areas under the receiver operating characteristic curve (Az) were calculated by considering histologic analysis (317 patients) or contrast-enhanced helical computed tomography followed by serial US 3-6 months apart (135 patients) as the reference standards. RESULTS: Different contrast enhancement patterns were observed according to lesion characteristics. During the late phase, benign lesions were predominantly hyper- or isoechoic relative to the adjacent liver parenchyma, whereas malignant lesions were predominantly hypoechoic. Review of the contrast-enhanced US scans after baseline image review yielded significantly improved diagnostic performance (P <.05). Overall diagnostic accuracy was 49% before versus 85% after review of the contrast-enhanced scan for reader 1 and 51% before versus 88% after review of the contrast-enhanced scan for reader 2. Diagnostic confidence-that is, the Az-was 0.820 before versus 0.968 after review of the contrast-enhanced scan for reader 1 and 0.831 before versus 0.978 after review of the contrast-enhanced scan for reader 2. CONCLUSION: The use of contrast-specific modes with a sulfur hexafluoride contrast agent led to improved characterization of solid focal liver lesions.     

Importance of evaluating all vascular phases on contrast-enhanced sonography in the differentiation of benign from malignant focal liver lesions

OBJECTIVE: Our objective was to evaluate the accuracy of a blood-pool sonographic contrast agent in the late phase compared with the three vascular phases for differentiation between benign and malignant focal liver lesions. SUBJECTS AND METHODS: In 152 patients (105 with chronic liver disease), 152 solid focal liver lesions characterized either by fine-needle biopsy or by dynamic CT or MRI were studied. The final diagnoses were metastasis for 24, hepatocellular carcinoma for 75, focal nodular hyperplasia for 13, regenerating or dysplastic nodule for 14, hemangioma for 22, cholangiocarcinoma for two, and another focal liver lesion for two. Real-time sonography was performed after a bolus injection of 2.4 mL of SonoVue, using a low mechanical index (< 0.2). All lesions were evaluated in the arterial, portal, and late phases; classified as benign or malignant; and correlated with final diagnoses. RESULTS: For discrimination between malignant and benign focal liver lesions, evaluation of all vascular phases improved the sensitivity from 78.4% to 98% and the accuracy from 80.9% to 92.7%, compared with evaluation of the late phase alone. The increase in accuracy was higher in patients with chronic liver disease (16.3%) than in those without (2.1%). CONCLUSION: Evaluation of SonoVue enhancement in all three vascular phases is superior to evaluation of SonoVue enhancement in the late phase alone, especially in patients with chronic liver disease.     

The real capabilities of contrast-enhanced ultrasound in the characterization of solid focal liver lesions

Contrast-enhanced US (CEUS) using intravenous agents is a rapidly evolving field even though the main clinically recognized application is the characterization of focal liver lesions. Several reports have described the improvement provided by CEUS in the characterization of focal liver lesions in comparison to unenhanced US. CEUS with low transmit power insonation allows the real-time assessment of focal liver lesion contrast enhancement and vascularity during the different dynamic phases after injection of an intravenous contrast agent. CEUS allows the accurate characterization of focal liver lesions as benign or malignant based on the lesion contrast enhancement pattern during the arterial phase and lesion vascularity during portal--late phase in comparison to the adjacent liver parenchyma. During the portal--late phase, benign lesions present prevalently a sustained contrast enhancement with hyper or isovascular appearance to the adjacent liver while malignant lesions present prevalently microbubble washout with hypovascular appearance. On the other hand, the histology of focal liver lesions can only be confidently predicted in selected cases by CEUS, as in liver haemangiomas presenting typical nodular peripheral enhancement with subsequent centripetal fill-in and focal nodular hyperplasia with central spoke wheel-shaped contrast enhancement.     

Hepatic tumors: contrast agent-enhancement patterns with pulse-inversion harmonic US

PURPOSE: To evaluate contrast agent-enhancement patterns in hepatic hemangiomas, hepatic metastases, and hepatocellular carcinomas (HCCs) at pulse-inversion harmonic ultrasonography (US) with a microbubble contrast agent. MATERIALS AND METHODS: Twenty hepatic hemangiomas in 20 patients and 41 malignant hepatic tumors in 23 patients (33 metastases and eight HCCs) were evaluated with pulse-inversion harmonic US. US images were obtained before injection and every 10-15 seconds after injection of a 4-g bolus (300 mg/mL) of SH U 508A (a microbubble contrast agent) for 5 minutes. The contrast-enhancement patterns of 61 hepatic lesions were assessed. RESULTS: Of 20 hemangiomas, 19 revealed peripheral enhancement, which was globular in 14 (70%) and rimlike in five (25%), with centripetal fill-in; the remaining one (5%) showed homogeneous enhancement. In 33 metastases, the enhancement was rimlike in 16 (48%), homogeneous in seven (21%), and stippled in two (6%); in the remaining eight metastases (24%), no enhancement was seen. Of eight HCCs, four (50%) showed homogeneous enhancement and the remaining four (50%) showed heterogeneous enhancement. Centripetal fill-in of lesions with intratumoral enhancement was not seen in any malignancy. CONCLUSION: Pulse-inversion harmonic US with a microbubble contrast agent is potentially useful for the specific diagnosis of hemangiomas that demonstrate characteristic enhancement features.     

Liver haemangiomas undetermined at grey-scale ultrasound: contrast-enhancement patterns with SonoVue and pulse-inversion US

The objective of this study was to describe the spectrum of contrast-enhancement patterns of hepatic haemangiomas undetermined at grey-scale ultrasound (US) on SonoVue-enhanced pulse-inversion (PI) US. Twenty patients (11 women, nine men) with 35 haemangiomas (size range: 1–7 cm; mean: 3.1 cm) undetermined at baseline US underwent PI at low M.I. (0.05–0.08) after i.v. injection of SonoVue. All haemangiomas were confirmed by typical helical computed tomography (CT) and/or magnetic resonance imaging (MRI) findings. US examinations were videotaped and then reviewed by two experienced radiologists blinded to the final diagnosis. Readers evaluated by consensus the baseline echogenicity and the dynamic enhancement pattern of each lesion, in comparison with adjacent liver parenchyma. After administration of SonoVue, 31/35 (88%) haemangiomas showed peripheral hyperechoic nodules in the arterial phase, followed by progressive centripetal fill-in, which was complete in 25/35 cases and incomplete in 6/35 cases. Three out of 35 (9%) haemangiomas showed rapid and complete fill-in in the arterial phase, which persisted in the portal and delayed phases. Finally, 1/35 haemangiomas (3%) showed a rim of arterial contrast enhancement with progressive and complete centripetal fill-in in portal-venous and delayed phases. In conclusion, PI after the administration of SonoVue enabled the depiction of typical contrast-enhancement patterns in haemangiomas undetermined at baseline US.     

肝脏局灶性结节性增生超声造影的典型特征和病灶大小的相关性研究

目的:探讨肝脏局灶性结节性增生(FNH)超声造影的典型特征与病灶大小的联系。方法:本组采用新型超声对比剂SonoVue和对比脉冲序列成像技术,对33例FNH患者共35个病灶行超声造影检查(CEUS),观察病灶的增强模式和其它声像图特征,分析轮幅状的增强模式和中央疤痕的发生率;其中26例由CT、MRI证实,其余7例经手术或穿刺病理证实。结果:24个直径>3cm的病灶22个(22/24,91.7%)动脉相早期呈轮幅状增强,而11个直径<3cm的病灶4个(4/11,36.4%)为轮幅状增强,本组共计26个(26/35,74.3%)病灶呈轮幅状增强。本组22个(22/35,62.9%)病灶可见中央疤痕,其中19个(19/24,79.2%)直径>3cm的病灶和3个(3/11,27.3%)直径<3cm的病灶可见上述特征。结论:多数直径>3cm的FNH超声造影动脉相表现为典型的轮幅状增强模式,延迟相可见中央疤痕,如果无轮幅状增强和中央疤痕等声像图特征,则超声造影难以鉴别诊断FNH与其它富血供的肿瘤。     

Detection of focal liver lesions at biphasic spiral CT: randomized double-blind study of the effect of iodine concentration in contrast materials

PURPOSE: To evaluate the effect of iodine concentration on the detection of focal liver lesions at biphasic spiral computed tomography (CT). MATERIALS AND METHODS: One hundred two patients (64 men, 38 women) with neoplastic (n = 85) and nonneoplastic focal lesions (n = 17) were prospectively assigned to biphasic injection group A or B and received 180 mL of iopromide containing 370 or 300 mg of iodine per milliliter, respectively, during spiral CT. Comparison included assessment of quantitative and qualitative parameters. RESULTS: Hepatic time-attenuation curves and mean hepatic enhancement in the portal venous phase and aortic time-attenuation curves in both arterial and portal venous phases were statistically superior in group A compared with group B. There was no significant difference in the mean enhancement in all lesions in either group. In contrast, among patients with hepatocellular carcinoma, mean contrast enhancement in lesions in the arterial phase was significantly superior in group A compared with group B. Blinded readers classified hepatic attenuation and lesion visibility as very good and as improved significantly more often in group A than in group B. CONCLUSION: A decrease in iodine concentration significantly affects aortic and hepatic contrast enhancement and may impair the detectability of focal liver lesions during biphasic spiral CT.     

Contrast-enhanced ultrasonography findings using a perflubutane-based contrast agent in patients with early hepatocellular carcinoma

Objective

We evaluated the contrast-enhanced ultrasonography (US) imaging features of early hepatocellular carcinomas (HCCs) and compared these findings with those obtained using contrast-enhanced computed tomography (CT).

Subjects and methods

Forty-three patients with 52 early HCCs with a mean maximal diameter of 15.6 mm were enrolled in this retrospective study. After confirming the location of the target lesion using fusion imaging combining conventional US and hepatobiliary phase of contrast-enhanced magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid, we evaluated findings of contrast-enhanced US using a perflubutane-based contrast agent. The contrast-enhanced US detection rates for hyper-vascularity in early HCCs were compared with those obtained for contrast-enhanced CT.

Results

Transient hypo-vascularity subsequent to iso-vascularity during arterial phase and iso-vascularity during portal and post-vascular phases were the predominant contrast-enhanced US findings seen for 25 (48.1%) of the 52 early HCCs. Nine (17.3%) showed iso-vascularity during all three phases, while 1 (1.9%) showed hypo-vascularity during all three phases. The remaining 17 (32.7%) showed partial or whole hyper-vascularity during arterial phase, iso-vascularity during portal phase, and iso- or hypo-vascularity during post-vascular phase. The detection rate for the hyper-vascularity of early HCCs using contrast-enhanced US (32.7%, 17/52) was significantly higher than that obtained using contrast-enhanced CT (21.2%, 11/52) (P < 0.05 by McNemar test).

Conclusion

Hypo-vascularity, iso-vascularity, and hyper-vascularity were observed during the arterial phase of contrast-enhanced US in 50.0%, 17.3%, and 32.7% of the early HCCs, respectively. Contrast-enhanced US was more sensitive than contrast-enhanced CT for the detection of hyper-vascularity in early HCCs. Of note, early HCCs might not exhibit the early arterial enhancement that is generally considered to be a typical finding for HCCs.     

MDCT of hypervascular hepatocellular carcinomas: a prospective study using contrast materials with different iodine concentrations

OBJECTIVE: The objective of our study was to investigate the effect of different iodine concentrations in contrast materials on the depiction of hypervascular hepatocellular carcinomas (HCCs) by MDCT. SUBJECTS AND METHODS: This prospective study involved 100 consecutive patients with chronic liver disease, including 27 patients with hypervascular HCCs. The first 50 patients received 100 mL of iopamidol at a concentration of 370 mg I/mL (group A) and the subsequent 50, 100 mL at 300 mg I/mL (group B); in both groups, the contrast material was administered at a rate of 3.0 mL/sec. Unenhanced scanning and four-phase enhanced scanning at 25, 40, 60, and 180 sec after the start of contrast injection were performed. The enhancement of the aorta, liver, and portal vein was measured during each phase. In addition, tumor-to-liver contrast was calculated for the 27 patients with hypervascular HCCs. Of the 27 patients with hypervascular HCCs, 15 were in group A and 12 were in group B. RESULTS: During all phases, aortic enhancement was significantly greater in group A than group B (p < 0.01). Hepatic enhancement was significantly greater in group A than group B at 60 and 180 sec (both p < 0.01). There was no significant difference in hepatic enhancement between the two groups at 25 and 40 sec. Tumor-to-liver contrast was significantly greater in group A than group B during the late arterial phase (40 sec, p = 0.02), although there was no significant difference at 25, 60, and 180 sec. CONCLUSION: Contrast materials with higher iodine concentration are more effective for depicting hypervascular HCCs on MDCT during the late arterial phase.     

Comparison of imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas associated with Budd-Chiari syndrome by contrast enhanced ultrasound

Purpose

To compare different imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas (HCCs) associated with Budd–Chiari syndrome (BCS) by contrast enhanced ultrasound (CEUS).

Materials and methods

A total of 32 chronic BCS patients (mean age, 42 years; age range, 18–59 years) with hepatic nodules who underwent CEUS were retrospectively studied. All patients had no the history of viral hepatitis. There were 23 patients with benign regenerative nodules (22 ± 9 mm; range, 8–42 mm) and 9 patients with HCCs (63 ± 21 mm; range, 26–90 mm). Lesion characteristics, including number, size, vascularization on color Doppler flow imaging, echogenicity, peripheral hypoechoic rim, and enhancement patterns in arterial, portal, and late phases on CEUS, were analyzed.

Results

There were significant differences in number and size of the lesions between two groups. No significant differences were observed in vascularity, echogenicity, and peripheral hypoechoic rim. Overall, there were significant differences in enhancement patterns in arterial, portal, and late phases between them on CEUS. Of 23 patients with benign regenerative nodules, 16 (70%) were center-to-periphery hyperenhanced and 7 patients (30%) were homogeneously hyperenhanced in arterial phase; the majority were homogeneously hyperenhanced in portal and late phases. Of 9 patients with HCCs, 8 (89%) were heterogeneously hyperenhanced in arterial phase and most of them were hypoenhanced in portal and late phases.

Conclusion

CEUS imaging characteristics of benign regenerative nodules radically differ from that of HCCs in BCS patients.     

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.     

螺旋CT双期或三期扫描对肝脏占位性病变的诊断

目的：分析肝脏螺旋CT双期或三期扫描表现，探讨其对原发性肝癌、肝转移瘤、肝血管瘤的诊断及鉴别诊断的意义。方法：经临床证实25例，均作螺旋CT平扫、动脉期、门脉期及部分平衡期和延迟期扫描，并分析螺旋CT多期扫描表现。结果：原发性肝癌动脉期明显强化而肝脏无强化，形成鲜明的对比，门脉期呈相对低密度或恢复到平扫时表现。肝血管瘤CT特征为动脉期呈边缘性环状、结节样强化，门脉期病灶边缘强化向中心强化并充满病灶呈高密度，平衡期呈等密度或低密度肝转移瘤表现多样化，周边强化或不均匀强化或不强化。结论：螺旋CT双期或三期扫描已作为对肝脏占位性病变的主要检查方法，并作为常规。     

Arterioportal shunt: prevalence in small hemangiomas versus that in hepatocellular carcinomas 3 cm or smaller at two-phase helical CT

PURPOSE: To compare the prevalence of arterioportal (AP) shunting associated with (a) small (< or =3 cm) hemangiomas and (b) hepatocellular carcinomas (HCCs) (< or =3 cm) at two-phase helical computed tomography (CT). MATERIALS AND METHODS: Two-phase helical liver CT was performed in 107 patients (61 men, 46 women; age range, 25-73 years; mean, 48.6 years) with 169 small hemangiomas and in 384 patients (292 men, 92 women; age range, 18-82 years; mean, 58.3 years) with 598 HCCs 3 cm or smaller. Diagnosis of HCC was verified with histologic findings (n = 30) or typical imaging and clinical findings (n = 568); that of all hemangiomas was verified with typical imaging and clinical findings. Three radiologists retrospectively reviewed all CT images in consensus. Contrast material-enhanced CT scans were obtained during the hepatic arterial and portal venous phases. AP shunt was considered to be present when wedge-shaped or irregularly shaped homogeneous enhancement peripheral to tumor appeared at hepatic arterial phase CT and isoattenuation or slight hyperattenuation in that area appeared at portal phase CT. The prevalence of AP shunting associated with hemangiomas and that associated with HCCs were compared with multivariate model testing. Speed of lesion enhancement (rapid enhancement, when extent of intratumoral enhancement at hepatic arterial phase CT was >50%; slow enhancement, when extent of intratumoral enhancement was < or =50%) and presence of AP shunt were correlated with chi2 or Fisher exact testing. RESULTS: AP shunts were more frequently found in hemangiomas (36 lesions [21.3%]) than in HCCs (25 lesions [4.2%]) (P <.001). Twenty-four (38%) of the 64 hemangiomas with rapid enhancement had AP shunts, whereas only 12 (11.4%) of the 105 hemangiomas with slow enhancement had AP shunts (P <.001). There was no significant difference between prevalence of AP shunt in the 573 HCCs with rapid enhancement (24 lesions, 4.2%) and that in the 25 HCCs with slow enhancement (one lesion, 4.0%). CONCLUSION: AP shunts were more frequently seen at two-phase helical CT in small hepatic hemangiomas than in HCCs and thus represent a suggestive but not specific finding of hemangioma. Small hemangiomas with AP shunts tend to show rapid rather than slow enhancement.