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.     

Atypical liver hemangiomas: contrast-enhancement patterns with SH U 508A and pulse-inversion US

AIM: To describe the enhancement patterns of atypical hepatic haemangiomas with Pulse Inversion Harmonic Imaging (PIHI) using SH U 508A (Levovist). MATERIALS AND METHODS: Twenty-five patients (15 women, 10 men; age range: 29-65 years, mean: 48.2 years) with 28 hepatic haemangiomas (size: 1.5 - 11.5 cm; mean: 4.6 cm) underwent PIHI before and after i.v. administration of Levovist. Selected images obtained at baseline and 25-30s, 55-60s and 240s after Levovist injection were sequentially reviewed to determine the changes in echogenicity of haemangiomas in comparison to surrounding liver parenchyma. RESULTS: At the baseline US study, 22/28 (79%) haemangiomas revealed highly inhomogeneous echotexture; 5/28 (18%) were homogeneously hypoechoic and 1/28 (3%) was isoechoic with respect to hepatic parenchyma. After Levovist administration, 16/28 (57%) haemangiomas showed peripheral hyperechoic nodules in the arterial phase with progressive centripetal fill-in in portal and late phases; such fill-in was complete in 14/16 cases and incomplete in 2/16. Four of twenty-eight (14%) haemangiomas revealed a rapid and complete homogeneous fill-in on arterial phase that lasted throughout the portal and late phases. Finally, 8/28 (29%) showed a rim-like enhancement with progressive and complete centripetal fill-in on portal and late phases. CONCLUSIONS: According to our results, PIHI with Levovist allows demonstration of typical enhancement patterns in most of atypical haemangiomas, thus providing useful diagnostic information for their characterization.     

Characterization of unifocal liver lesions with pulse inversion harmonic imaging after Levovist injection: preliminary results

The aim of this study was to evaluate capabilities of pulse inversion harmonic imaging (PIHI) in characterization of unifocal liver lesions. We evaluated with PIHI (HDI5000, ATL, Bothell, Wash.) and spiral CT 46 consecutive patients with a single liver lesion identified by fundamental US [7 hepatocellular carcinomas (HCC), 2 cholangiocarcinomas, 7 focal nodular hyperplasias (FNH), 17 hemangiomas and 13 metastases]. The PIHI was performed before and 30 s, 2 and 4 min after bolus administration of Levovist (2.5 g, 300 mg/ml). Scans were digitally stored and reviewed using a dedicated software. Hepatocellular carcinoma was hyperechoic on 30-s scan, and hypoechoic (n = 5) or isoechoic (n = 2) on 2-min scan. Cholangiocarcinoma had inhomogeneous persistent enhancement. Focal nodular hyperplasia was hyperechoic (n = 5) or isoechoic (n = 2) on 30-s scan, hyperechoic (n = 4), isoechoic (n = 2) or slightly hypoechoic (n = 1) on 2-min scan. Large hemangioma revealed peripheral enhancement on 30-s scan which extended centripetally on 2-min scan. Small hemangioma appeared isoechoic on 2-min scan in all but two cases in which they were hypoechoic on 2-min scans and hyperechoic on 4-min scan. Metastasis was hypoechoic on all scans, 70% with rim enhancement. Similar changes in enhancement pattern have been observed at spiral CT. The 30-s and the 2-min scans revealed a conclusive importance in characterization of HCC, cholangiocarcinoma, and large hemangioma. The 2-min scan often furnished enough information for characterization of small hemangioma and metastasis. The 4-min scan allowed characterization of two hemangiomas which appeared hypoechoic on 2-min scans. In the other cases it did not provide further information. Diagnosis of FNH is usually reached with Colour Doppler US; PIHI should be used when colour Doppler is biased by artefacts or when colour Doppler findings are not characteristic. Our results seem to show that PIHI could be a valuable alternative diagnostic approach to spiral CT for unifocal liver lesion characterization. This hypothesis needs to be confirmed with an increased number of lesions.     

Characterization of renal tumours with pulse inversion harmonic imaging by intermittent high mechanical index technique: initial results

Our objective was to evaluate whether contrast-specific ultrasound (US) technique pulse inversion harmonic imaging (PIHI) with Levovist could reveal differential morphological features in solid and cystic renal masses. Twenty-six renal masses in 26 patients were evaluated by PIHI after Levovist injection with intermittent high mechanical index stimulation, performed every 10–15 s during arterial and delayed phase. Helical CT (HCT; n=6) or histological findings on surgical/bioptic specimen (n=20) were considered as the reference procedures for definitive diagnosis. Eleven solid renal cell carcinomas (RCCs), 1 embryonal matanephric adenoma (EMA), 7 angiomyolipomas (AMLs), 4 cystic RCCs and 3 complex inflammatory cysts were identified. Solid RCCs revealed a much higher (p<0.05) contrast enhancement than AMLs with typical pattern on conventional US (n=6). The EMA and AML with atypical pattern on conventional US (n=1) revealed intense contrast enhancement during arterial phase, progressively decreasing during delayed phase. Cystic RCCs and complex inflammatory cysts revealed intense contrast enhancement on the peripheral thick wall during arterial phase decreasing on delayed phase. The PIHI has been shown to differentiate solid RCC from typical AML by contrast enhancement assessment after Levovist injection, but differential diagnosis both in solid and in cystic renal masses still remains difficult. Electronic Publication     

Differential patterns of contrast enhancement in different focal liver lesions after injection of the microbubble US contrast agent SonoVue

PURPOSE: To identify differential contrast enhancement patterns in different focal hepatic lesions after injection of the microbubble contrast agent SonoVue using high or low acoustic power imaging. MATERIAL AND METHODS: Forty-seven focal hepatic lesions (1-8 cm) were detected in 45 patients at unenhanced gray-scale ultrasound (US) and evaluated by color Doppler (CD) US with spectral analysis of tumoral vessels. Lesions were subsequently evaluated by US contrast specific modes after IV bolus administration of 2,4-4,8 ml of SonoVue, by intermittent high acoustic power (18 patients) or by continous low acoustic power imaging (27 patients), during arterial, portal and late phase. Subjective evaluation of lesions appearance before and after SonoVue injection was performed. For final diagnosis multiphasic helical CT (21 patients) and/or fine needle US guided biopsy (24 patients) were considered as the reference procedures. RESULTS: Final diagnoses comprised 22 hepatocellular carcinomas (HCCs; 1,5-6 cm), 2 macroregenerative nodules (RNNs; 1-2 cm), 10 metastasis (2-3,5 cm), 10 hemangiomas (2-6 cm) and 3 focal nodular hyperplasias (FNHs; 1-3 cm). On CD evaluation HCCs revealed peripheral basket shaped (12/22) or intranodular (10/22) arterial pattern while, after SonoVue injection HCCs revealed diffuse contrast enhancement during arterial phase with contrast washout during portal and late phase. Metastases did not reveal flow signals on CD or contrast enhancement after SonoVue injection, except for 2 metastases which revealed peripheral and central vessels on CD and a diffuse contrast enhancement during arterial phase, appearing hypoechoic to the adjacent liver during portal and late phase. RNNs revealed dotted contrast-enhancement during portal and late phase with isoechoic appearance to the adjacent liver. Hemangiomas revealed some peripheral venous flows on CD and a peripheral nodular contrast enhancement during arterial phase with a centripetal fill-in during portal and late phase. FNHs revealed low resistance peripheral or central arterial vessels and a diffuse contrast enhancement during arterial phase, preceded or not by central spoke wheel shaped contrast enhancement, and a persistent iso-hyperechogenicity during portal and late phase. CONCLUSIONS: SonoVue injection has showed to identify differential contrast enhancement patterns in different focal hepatic lesions.     

Pulse-inversion harmonic imaging improves lesion conspicuity during US-guided biopsy

PURPOSE: To assess the feasibility of percutaneous biopsy of low-conspicuity focal liver lesions with use of pulse-inversion harmonic imaging (PIHI) guidance in the late phase after injection of microbubble contrast agent. MATERIALS AND METHODS: Twelve patients referred for ultrasound (US)-guided biopsy had liver lesions lacking adequate conspicuity to undergo biopsy under conventional ultrasound (US) guidance. They underwent biopsy procedures performed with the use of PIHI guidance in the late phase after injection of Levovist. The conspicuity of lesions, procedure time, number of passes, and success and complication rates were documented and compared to a control group. The control group consisted of retrospective analysis of 19 patients who had undergone conventional US-guided biopsy procedures performed by the same radiologist. RESULTS: After contrast material injection, all lesions had sufficient increases in conspicuity to be targeted under PIHI guidance. Procedure time was prolonged in the PIHI group (66 minutes; range, 30-120 min; vs control, 33 min; range, 15-77 min; P <.01, Wilcoxon signed-rank test). The number of passes was greater in the PIHI group (1.9 +/- 0.3; vs control, 1.4 +/- 0.6; P <.01, chi(2) test). No statistically significant difference was observed when comparing success and complication rates. CONCLUSION: PIHI in the late phase after injection of Levovist generated clear delineation of focal liver lesions in all cases, allowing an accurate and safe sampling. This technique broadens the scope of US-guided biopsy to lesions lacking adequate conspicuity on conventional US.     

Detection of liver metastases by pulse inversion harmonic imaging during Levovist late phase: comparison with conventional ultrasound and helical CT in 160 patients

The aim of this study was to evaluate capabilities of pulse inversion harmonic imaging (PIHI) with Levovist in detection of liver metastases compared with conventional ultrasound (US) and helical CT (HCT). One hundred sixty consecutive patients with known malignancies were evaluated by conventional US, PIHI 2 min (40 patients) or 4 min (120 patients) after Levovist injection and HCT. Conspicuity and number of the identified metastatic lesions were evaluated and assessed by statistical analysis (significance p<0.05). Mean diameter of the smallest identified metastases was computed for conventional US, PIHI and HCT. In cases where PIHI revealed more lesions suspicious for metastases than HCT, intraopertive US with surgical biopsy or 3–6-month US follow-up were performed to confirm diagnosis. Images were stored on magneto-optical disk and evaluated off-line by a dedicated software. Metastases conspicuity was significantly improved on PIHI if compared with conventional US (p<0.05). In 49 patients all the employed imaging techniques did not reveal any lesion, whereas in the remaining 111 patients, 28 patients revealed more than five metastatic lesions and 83 patients presented from one to five metastatic lesions. In comparison with conventional US, PIHI revealed more metastases in 39/83 (47%), the same number in 44/83 (53%) and a lower number in 0/83 (0%) patients. In comparison with HCT, PIHI revealed more metastases in 10/83 (12%), the same number in 61/83 (74%) and a lower number in 12/83 (14%) patients. Average number ± SD (standard deviation) of confirmed metastases for patients was 2.21±1.6 for conventional US, 3.1±2.44 for PIHI and 3.05±2.41 for HCT. The difference between PIHI and conventional US was statistically significant (p<0.0001), whereas the difference between PIHI and HCT was not significant (p=0.9). The smallest identified metastases presented 3-mm mean diameter on PIHI, 5-mm on HCT and 7-mm on conventional US. PIHI with Levovist is a reliable technique in metastases detection. Electronic Publication     

Detection of liver metastases with pulse inversion harmonic imaging: preliminary results

The aim of this study is to evaluate capability of contrast enhanced ultrasonography (US) using pulse inversion harmonic imaging (PIHI) to detect liver metastases in comparison to fundamental B-mode ultrasound and spiral CT. Thirty-six consecutive patients with known malignancies and sonographically proved or suspicious liver metastases have been examined with fundamental B-mode US, with PIHI 2', 4' and 6' after Levovist injection and with four phase spiral-CT. Presence, conspicuity and number of lesions have been evaluated comparing PIHI with fundamental B-mode US and spiral-CT. A strong grey-scale enhancement of the liver parenchyma has been observed 2' and 4' after Levovist injection. The optimum parenchymal enhancement and contrast difference between liver and metastases was observed during the 2' measurements. PIHI revealed more lesions than fundamental B-mode US in 56 % of patients, while in 39 % and in 5 % revealed respectively the same number and fewer lesions. PIHI and spiral-CT were in agreement in 67 % of patients, while in 22 % and 11 % PIHI revealed respectively more and fewer lesions. PIHI accurancy presents restrictions in anterior superficial and in deep liver areas, whereas it may be superior to spiral-CT in studying sub-diaphragmatic liver regions.     

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.     

Detection of Hepatic VX2 Tumors in Rabbits: Comparison of Conventional US and Phase-Inversion Harmonic US During the Liver-Specific Late Phase of Contrast Enhancement

Objective

To compare phase-inversion sonography during the liver-specific phase of contrast enhancement using a microbubble contrast agent with conventional B-mode sonography for the detection of VX2 liver tumors.

Materials and Methods

Twenty-three rabbits, 18 of which had VX2 liver tumor implants, received a bolus injection of 0.6 g of Levovist (200 mg/ml). During the liver-specific phase of this agent, they were evaluated using both conventional sonography and contrast-enhanced phase-inversion harmonic imaging (CE-PIHI). Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained. The conspicuity, size and number of the tumors before and after contrast administration, as determined by a sonographer, were compared between the two modes and with the pathologic findings.

Results

CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits. For VX2 tumors detected at both conventional US and CE- PIHI, conspicuity was improved by contrast-enhanced PIHI. On examination of gross specimens, 52 VX2 tumors were identified. Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05). In particular, conventional US detected only three (8.3%) of the 36 tumors less than 10 mm in diameter, but CE-PIHI detected 19 such tumors (52.8%) (p < 0.05).

Conclusion

Compared to conventional sonography, PIHI performed during the liver-specific phase after intravenous injection of Levovist is markedly better at detecting VX2 liver tumors.     

Centrifugal (inside-out) enhancement of liver hemangiomas: a possible atypical appearance on contrast-enhanced US

OBJECTIVE: To report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography. MATERIALS AND METHODS: Baseline and SonoVue-enhanced ultrasonography of 92 patients with 158 liver hemangiomas - considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up - were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases. RESULTS: After administration of SonoVue, 12/158 hemangiomas (7.6%) (size range: 1-7cm; mean: 3.2cm) in seven patients (5 women, 2 men; age range: 34-71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in. CONCLUSION: Radiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma.     

Hepatic Cavernous Hemangioma in Cirrhotic Liver: Imaging Findings

Objective

To document the imaging findings of hepatic cavernous hemangioma detected in cirrhotic liver.

Materials and Methods

The imaging findings of 14 hepatic cavernous hemangiomas in ten patients with liver cirrhosis were retrospectively analyzed. A diagnosis of hepatic cavernous hemangioma was based on the findings of two or more of the following imaging studies: MR, including contrast-enhanced dynamic imaging (n = 10), dynamic CT (n = 4), hepatic arteriography (n = 9), and US (n = 10).

Results

The mean size of the 14 hepatic hemangiomas was 0.9 (range, 0.5-1.5) cm in the longest dimension. In 11 of these (79%), contrast-enhanced dynamic CT and MR imaging showed rapid contrast enhancement of the entire lesion during the early phase, and hepatic arteriography revealed globular enhancement and rapid filling-in. On contrast-enhanced MR images, three lesions (21%) showed partial enhancement until the 5-min delayed phases. US indicated that while three slowly enhancing lesions were homogeneously hyperechoic, 9 (82%) of 11 showing rapid enhancement were not delineated.

Conclusion

The majority of hepatic cavernous hemangiomas detected in cirrhotic liver are small in size, and in many, hepatic arteriography and/or contrast-enhanced dynamic CT and MR imaging demonstrates rapid enhancement. US, however, fails to distinguish a lesion of this kind from its cirrhotic background.     

Differentiation between hepatoma and hemangioma with inversion-recovery snapshot FLASH MRI and Gd-DTPA.

Thirty-eight patients with focal liver tumors (20 hepatomas, 18 hemangiomas) were studied by dynamic sequential inversion recovery (IR) snapshot fast low angle shot (FLASH) MR imaging with Gd-DTPA. Immediately after 0.05 mmol/kg Gd-DTPA was administered intravenously for 2-3 s followed by flushing with normal saline for 4-5 s, 10 images were obtained in the first 20 s (time zero is the end of flush, early phase). Then, one image every 30 s from 1 to 3 min (late phase) and images at 5 min and 7 min (delayed phase) were obtained serially. Hepatomas showed total enhancement in 18 of 20 patients in the early phase, and isointense or low intensity enhancement with respect to the surrounding liver parenchyma in 18 patients in the late to delayed phases. Hemangiomas showed peripheral enhancement in 14 patients in the early phase, but did not show total enhancement (except for two hemangiomas less than 3 cm in size) in the early phase, and showed high intensity enhancement in 15 patients in the late phase. Ninety percent of hepatomas and 82% of hemangiomas showed their characteristic enhancement patterns in the early to delayed phases. We conclude that dynamic sequential IR snapshot FLASH MR images enhanced with Gd-DTPA can facilitate differentiation between hepatomas and hemangiomas.     

Discrimination of small hepatic hemangiomas from hypervascular malignant tumors smaller than 3 cm with three-phase helical CT

PURPOSE: To compare the appearance of small hepatic hemangiomas at nonenhanced and contrast material-enhanced helical computed tomography (CT) with that of small (<3-cm) hypervascular malignant liver tumors and to evaluate the accuracy of multiphase helical CT for differentiating small hemangiomas from small hypervascular malignant tumors. MATERIALS AND METHODS: Radiologists reviewed multiphase helical CT liver images in 86 patients with 37 hemangiomas and 49 malignant liver tumors. They evaluated lesion type and degree of enhancement for change from arterial to portal venous phase. They rated their confidence in the discrimination of hemangiomas from malignant tumors. RESULTS: At arterial phase CT, enhancement similar to aortic enhancement was observed in 19%-32% of hemangiomas and 0%-2% of malignant tumors; globular enhancement, in 62%-68% and 4%-12%, respectively. At portal venous phase CT, enhancement similar to blood pool enhancement was observed in 43%-54% of hemangiomas and 4%-14% of malignant tumors; globular enhancement, in 46%-49% and 0%-2%, respectively. For all readers and all phases of enhancement, the area under the receiver operating characteristic curves was 0.81-0.87, indicating that inherent accuracy of CT is high and that there was no significant difference (P >.28) in overall accuracy. Readers diagnosed hemangiomas with 47%-53% mean sensitivity with all enhancement phases and diagnosed malignant lesions with 95% mean specificity. CONCLUSION: Small hemangiomas frequently show atypical appearances at CT. Two-phase helical CT does not improve sensitivity but does improve specificity for differentiating hemangiomas from hypervascular malignant tumors.     

Centrifugal (inside-out) enhancement of liver hemangiomas: A possible atypical appearance on contrast-enhanced US

ObjectiveTo report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography.Materials and methodsBaseline and SonoVue^®-enhanced ultrasonography of 92 patients with 158 liver hemangiomas – considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up – were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases.ResultsAfter administration of SonoVue^®, 12/158 hemangiomas (7.6%) (size range: 1–7 cm; mean: 3.2 cm) in seven patients (5 women, 2 men; age range: 34–71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in.ConclusionRadiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma.     

小转移性肝癌的超声造影表现及其应用价值

目的：观察小于3cm的恶性肿瘤肝转移病灶的超声造影表现并探讨其临床应用价值。方法：对77例已确诊为恶性肿瘤肝转移的患者进行Sono Vue超声造影检查,记录并分析不同大小病灶的造影后各时相增强的特征。结果：大小〈1.0cm的4例病灶,动脉相均表现为整体团状增强;大小为〉1.0cm～≤2.0cm的39例病灶中,动脉相整体团状增强18例,环状增强17例,不均匀整体增强2例,无增强2例;大小为〉2.0cm～≤3.0cm的34例病灶中,动脉相整体团状增强6例,环状增强24例,不均匀整体增强3例,等增强1例。病灶大小与增强模式之间比较有统计学意义（P〈0.01）。结论：在小转移性肝癌中,病灶的增强模式与大小有关;超声造影对恶性肿瘤临床分期及治疗方案的选择有重要的应用价值。     

Atypical imaging findings of infantile hemangioendothelioma: a case report

Infantile hemangioendothelioma is the third most common hepatic tumor in children, and the most common benign vascular tumor of the liver in infancy. On computed tomography (CT) and magnetic resonance imaging (MRI), typical enhancement patterns similar to those seen in adult hemangiomas may help establish the diagnosis. However, atypical enhancement patterns may also occur. In this paper, we report a rare form of solitary infantile hemangioendothelioma that showed a rim-like calcification and rim-like enhancement on CT and MRI.     

Clinical utility of contrast-enhanced three-dimensional ultrasound imaging with Sonazoid: Findings on hepatocellular carcinoma lesions

ObjectivesWe investigated clinical utility of contrast-enhanced three-dimensional ultrasound (CE 3D US) imaging with contrast medium Sonazoid for demonstrating characteristic enhancement of hepatocellular carcinoma (HCC).MethodsAmong 115 focal liver tumors undergoing CE 3D US imaging, 70 HCCs confirmed with contrast-enhanced multi-detector computed tomography, contrast-enhanced magnetic resonance imaging or histopathologic examination were retrospectively analyzed. CE 3D US imaging was performed using Autosweep 3D scan functionality in the early, middle and late phase, after bolus injection of 0.2 ml Sonazoid. The CE 3D tomographic images reconstructed in parallel slices and sonographic angiogram images were independently reviewed by two reviewers. Kappa values were used to assess inter-reviewers’ agreement.ResultsTUI images showed most of HCCs were detected with intratumoral vessels and early tumor enhancement in the early phase, expressed homogenous or heterogeneous tumor enhancement in the middle phase, and became hypoechoic or isoechoic in the late phase. The kappa values in the early, middle and late phase for inter-reviewer agreements regarding the characteristic enhancement of tumors were 0.817, 0.774, and 0.785. In addition, TUI images demonstrated satellite foci and tortuous tumor vessels in three orthogonal planes. Sonographic angiogram reconstructed by different rendering modes showed the vessels and tumor stain in spatial view. The spatial configuration of anatomic structures was revealed on basis of both TUI and sonographic angiogram images.ConclusionCE 3D US imaging, with spatial visualization, is clinically useful to exhibit the characteristic enhancement of HCC tumors objectively.     

Color Doppler flow imaging of liver tumors

A differential diagnosis of liver tumors was attempted on the basis of the pattern of blood flow within and around tumors on color Doppler flow images. The study comprised 35 patients with liver mass lesions: 20 patients had hepatocellular carcinoma, six had hemangiomas, four had metastatic liver cancers, one had cholangiocellular carcinoma, one had focal fatty liver, and three had liver cysts. A basket pattern (a fine blood-flow network surrounding the tumor nodule) was observed in 15 (75%) of the 20 hepatocellular carcinomas. An image of vessels within the tumor (blood flow that runs into and branches within the tumor) was observed in 13 (65%) of the 20 hepatocellular carcinomas. These two findings were observed only in hepatocellular carcinomas; even when the tumor was smaller than 2 cm in diameter, these findings were observed frequently. In the patients with multiple hepatic metastases, a "detour" pattern (a dilated portal vein meandering around the tumor nodules) was observed. In three of the six hemangiomas, a "spot" pattern (color-stained dots or patches in the central region of the tumor) was seen. Our experience suggests that hepatocellular carcinomas have a characteristic appearance on color Doppler flow images.     

Qualitative assessment of tumor vascularity in hepatocellular carcinoma by contrast-enhanced coded ultrasound: comparison with arterial phase of dynamic CT and conventional color/power Doppler ultrasound

The purpose of this study was to evaluate the detection rate of tumor vessels and vascularity in hepatocellular carcinoma (HCC) by contrast-enhanced coded US using Levovist, and to compare with conventional color/power Doppler US (CDUS) and dynamic CT. Ninety nodules (72 hypo/isoechoic nodules, 18 hyperechoic nodules) in 61 patients were studied. We observed tumor vessels by continuous transmission at the early vascular phase (40 s following administration of Levovist) and vascularity by intermittent transmission (intervals of 2–3 s) at the late vascular phase (40 to approximately 120 s). The detection rate of tumor vessels at the early vascular phase was 97% in hypo/isoechoic nodules and 70% in hyperechoic nodules with high density in dynamic CT being higher than that by CDUS. Tumor vascularity at the late vascular phase in hypo/isoechoic and hyperechoic nodules was hyper-enhancement in 78 and 40%, iso-enhancement in 19 and 40%, and hypo-enhancement in 3 and 0%, respectively. The detection rates of tumor vessels and vascularity in hyperechoic nodules were similar to those by CDUS. The detection rates of tumor vessels and vascularity were not affected by the tumor size in HCC tumors with high density in dynamic CT. Contrast-enhanced US with Levovist was superior to CDUS and equal to dynamic CT to assess tumor vessels in hypo/isoechoic nodules. Although it was equal to CDUS for hyperechoic nodules, this modality is useful in evaluating tumor hemodynamics.