Evaluation of hepatic focal nodular hyperplasia with contrast-enhanced gray scale harmonic sonography: initial experience.

OBJECTIVE: To assess the potential of contrast-enhanced gray scale harmonic sonography in the evaluation of the typical vascular and enhancement patterns of hepatic focal nodular hyperplasia. METHODS: Thirteen patients with 13 lesions of hepatic focal nodular hyperplasia underwent contrast-enhanced gray scale harmonic sonography. After the injection of a microbubble contrast agent (SH U 508A), gray scale harmonic sonographic studies using a Coded Harmonic Angio technique were performed with a combination of a period of continuous scanning to assess the vascular pattern (vascular imaging) and interval delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed by consensus of 2 experienced radiologists. RESULTS: In 12 (92%) of 13 lesions, vascular imaging during the arterial phase showed central arteries of a spoked wheel pattern, whereas the remaining lesion had stippled vascularity. On acoustic emission imaging, 11 (85%) of 13 lesions were hyperechoic during the early phase, and the remaining 2 (15%) were isoechoic compared with surrounding parenchyma. Ten (77%) of 13 lesions remained either hyperechoic (5 of 13) or isoechoic (5 of 13) during the delay phase, whereas the remaining 3 lesions (23%) were hypoechoic. CONCLUSIONS: Contrast-enhanced gray scale harmonic sonography showed the typical vascularity of a spoked wheel pattern during the vascular phase and persistent enhancement on serial acoustic emission imaging in most cases of hepatic focal nodular hyperplasia, and thereby it can be a promising technique in noninvasive diagnosis of this entity.     

Contrast‐enhanced sonography in the diagnosis of hepatic hemangiomas: Atypical appearance due to the washout of microbubbles

Contrast‐enhanced sonography (CEUS) examination permits identification of hemangioma of the liver in most cases. This method is particularly useful when the ultrasound pattern is atypical on standard grayscale examination. CEUS appearances suggestive of hemangioma are peripheral globular enhancement, progression of enhancement toward the center of the nodule, and persistence of enhancement in the late phase. We present seven cases of hemangioma, which were atypical on CEUS examination due to washout during the portal and late phases, resulting in a hypoenhanced appearance compared with the adjacent liver parenchyma. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 41 :361–365, 2013     

Extra-low acoustic power harmonic images of the liver with perflutren: novel imaging for real-time observation of liver perfusion.

OBJECTIVE: The features of images below the extra-low mechanical index level were studied to elucidate a suitable mechanical index level for observing real-time and continuous harmonic images of rabbit livers with VX-2 tumors with the use of perflutren. METHODS: Eight New Zealand White rabbits, 2 with healthy livers and 6 with VX-2 tumors, were examined by harmonic imaging (1.85 and 3.7 MHz) at a frame rate of 17 Hz under various mechanical index levels. RESULTS: Real-time enhanced images of the liver were observed continuously in all rabbits. Vascular images were more clearly visualized at the low mechanical index level (mechanical index, 0.18) than at any other level. However, predominant enhanced images of the whole liver were observed only at the extra-low mechanical index level (mechanical index, 0.06). In VX-2 tumors, tumor vessels were shown more clearly at a low acoustic power level than at an extra-low level. The histologically proved area of viable tumor was enhanced as a stain in the tumor nodule at an extra-low mechanical index level. CONCLUSIONS: Harmonic imaging under extra-low mechanical index levels with perflutren could provide real-time and continuous enhanced images of the liver, which would contribute to improvement of the diagnostic ability of contrast-enhanced sonography in liver diseases.     

The role of late-phase pulse inversion harmonic imaging in the detection of occult hepatic metastases.

OBJECTIVE: The purpose of this study was to investigate the efficacy of late-phase pulse inversion harmonic imaging (PIHI) in detecting occult metastases and to compare the results with helical computed tomography (CT) in a group of patients whose fundamental liver sonographic results were normal. METHODS: Thirty-two patients (21 women and 11 men; age range, 20-87 years) with a known primary malignancy were enrolled in the study. The patients were evaluated with conventional sonography, unenhanced PIHI, and PIHI 3 minutes after the injection of Levovist (SH U 508A; Schering AG, Berlin, Germany). All patients also underwent triphasic helical CT within 1 week after sonography. In 1 patient, mangafodipir-enhanced magnetic resonance imaging was performed as part of the clinical workup. RESULTS: After Levovist injection, in 4 (12.5%) of 32 patients, at least 1 hypoechoic lesion was detected by PIHI; multiple lesions were shown in 1 patient. The mean diameter of newly detected lesions was 12 mm. Triphasic helical CT also showed all of the lesions that were detected by PIHI. The diagnoses were confirmed by biopsy and CT findings in 2 patients and by the typical CT and magnetic resonance imaging findings in 1 patient. For the fourth patient, the diagnosis was confirmed by follow-up and CT. Conclusions. Late-phase PIHI is comparable to helical CT for detecting occult hepatic metastases, but it protects patients from the potentially hazardous effects of radiation and iodinated contrast agents. Further series involving a larger number of patients are needed to determine its place in the evaluation of cancer staging and treatment planning.     

Hemodynamic and morphologic changes of peripheral hepatic vasculature in chronic liver disease: a preliminary study by contrast-enhanced coded phase-inversion harmonic sonography

To investigate whether observing the morphology of the peripheral hepatic vasculature and the hemodynamics of microbubble arrival time in these vessels can provide useful information for the diagnosis of liver disease, Five normal volunteers and 16 patients were studied by contrast-enhanced coded phase-inversion harmonic sonography. Vessel images of the peripheral vessels were observed in real time after intravenous injection of Levovist. The time when the microbubbles appeared in the peripheral vessels was measured. Three patterns of morphologic change of the peripheral hepatic vasculature were seen, marked, slight, and no abnormal changes. The microbubble arrival times at the peripheral vessels were all shorter in patients with cirrhosis than chronic hepatitis or normal subjects. Marked, slight, and no abnormal morphologic changes of the peripheral hepatic vasculature in patients with liver cirrhosis were found in five, one and zero of the six patients, respectively. Those patients with chronic hepatitis, were found in one, six and three of the ten patients, respectively. There was a significant difference among the different groups (P < 0.001). Evaluating the hemodynamics and morphology by contrast-enhanced coded pulse-inversion harmonic sonography may offer useful information in the diagnosis of liver disease.     

Characterization of hyperechoic focal liver lesions: quantitative evaluation with pulse inversion harmonic imaging in the late phase of levovist.

OBJECTIVE: The aim of this study was to evaluate hyperechoic focal liver lesions with pulse inversion harmonic imaging in the late phase of SH U 508A (Levovist; Schering AG, Berlin, Germany) and to determine whether quantitative evaluation improves the characterization of the lesions. METHODS: Twenty-six patients with hyperechoic liver lesions were enrolled in this study. Pulse inversion harmonic imaging was performed before and after administration of Levovist. Scan data were digitally stored, and each lesion was analyzed with a personal computer-based quantification package. All lesions were confirmed by histologic or triphasic spiral computed tomographic examinations. The intensity was measured in decibels in regions of interest drawn within the lesion and surrounding liver parenchyma. The lesion-liver ratios were than calculated. After contrast agent administration, a ratio equal to or greater than 1 was presumed benign, whereas a ratio of less than 1 was considered malignant. RESULTS: Nine malignant (7 metastases, 1 hepatocellular carcinoma, and 1 cholangiocarcinoma) and 17 benign (14 hemangioma, 1 focal nodular hyperplasia, 1 focal fatty change, and 1 inflammatory pseudotumor) hyperechoic lesions were quantitatively evaluated. All malignant (n = 9) and 2 benign lesions (1 hemangioma and 1 inflammatory pseudotumor) had ratios of less than 1. In 15 of 17 benign lesions, the ratios were equal to or greater than 1. The intensity ratios calculated for benign and malignant lesions showed a statistically significant difference (P < .05). CONCLUSIONS: Pulse inversion harmonic imaging with quantitative evaluation facilitates the differential diagnosis of hyperechoic focal liver lesions. A lesion-liver ratio equal to or greater than 1 predicts a benign nature, assuming that malignant lesions show a ratio of less than 1.     

Comparing differential tissue harmonic imaging with tissue harmonic and fundamental gray scale imaging of the liver.

OBJECTIVE: The purpose of this study was to compare fundamental gray scale sonography, tissue harmonic imaging (THI), and differential tissue harmonic imaging (DTHI) for depicting normal and abnormal livers. METHODS: The in vitro lateral resolution of DTHI, THI, and sonography was assessed in a phantom. Sagittal and transverse images of right and left hepatic lobes of 5 volunteers and 20 patients and images of 27 liver lesions were also acquired. Three independent blinded readers scored all randomized images for noise, detail resolution, image quality, and margin (for lesions) on a 7-point scale. Next, images from the same location obtained with all 3 modes were compared blindly side by side and rated by all readers. Contrast-to-noise ratios were calculated for the lesions, and the depth of penetration (centimeters) was determined for all images. RESULTS: In vitro, the lateral resolution of DTHI was significantly better than fundamental sonography (P = .009) and showed a trend toward significance versus THI (P = .06). In the far field, DTHI performed better than both modes (P < .04). In vivo, 450 images were scored, and for all parameters, DTHI and THI did better than sonography (P < .002). Differential tissue harmonic imaging scored significantly higher than THI with regard to detail resolution and image quality (P < .001). The average increase in penetration with THI and DTHI was around 0.6 cm relative to sonography (P < .0001). The contrast-to-noise ratio for DTHI showed a trend toward significance versus THI (P = .06). Side-by-side comparisons rated DTHI better than THI and sonography in 54% of the cases (P < .007). CONCLUSIONS: Tissue harmonic imaging and DTHI do better than fundamental sonography for hepatic imaging, with DTHI being rated the best of the 3 techniques.     

Clinical use of renal perfusion imaging by means of harmonic sonography with a microbubble contrast agent in patients after renal transplantation: preliminary study.

OBJECTIVE: The purpose of this research was to determine the feasibility of renal perfusion imaging by means of harmonic sonography with a microbubble contrast agent for the evaluation of renal perfusion after renal transplantation compared with technetium Tc 99m diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) scans. METHODS: During a 10-month period, 100 patients with renal transplantation that included normal perfusion (n=68) and delayed perfusion including chronic rejection (n=19), acute rejection (n=9), arterial stenosis (n=2), and urinary stricture (n=2) underwent sonographic renal perfusion imaging and (99m)Tc-DTPA scans. Sonographic images were obtained every 3 seconds for a total of 3 minutes after administration of a bolus injection of 4 g of the microbubble contrast agent at a concentration of 300 mg/mL. Sonographic renal perfusion images were converted into a renal perfusion curve, and the calculated time at the peak of the curve (T(peak)) was compared with that of the (99m)Tc-DTPA scan. RESULTS: The T(peak) with the (99m)Tc-DTPA scan was 14.9 seconds in the normal group and 33 seconds in the delayed perfusion group. The T(peak) on sonographic renal perfusion images was 25 seconds in the normal group and 44.8 seconds in the delayed perfusion group. Sonographic renal perfusion images showed good correlation with the (99m)Tc-DTPA scan (r=0.74; P=.0001). The cutoff value of the T(peak) on sonographic renal perfusion images was 35 seconds (sensitivity=85%; specificity=90%). CONCLUSIONS: The renal perfusion images obtained by means of harmonic sonography with a microbubble contrast agent constitute an effective sonographic technique for the evaluation of renal perfusion abnormalities after renal transplantation compared with a (99m)Tc-DTPA scan.     

Assessment of the therapeutic response of hepatocellular carcinoma treated with transcatheter arterial chemoembolization: comparison of contrast-enhanced sonography and 3-phase computed tomography.

OBJECTIVE: The purpose of this study was to compare contrast-enhanced sonography with 3-phase computed tomography (CT) in assessing the therapeutic response of hepatocellular carcinomas (HCCs) treated with transcatheter arterial chemoembolization (TACE). METHODS: Twenty-nine nodular HCCs treated with TACE were examined with contrast-enhanced sonography, 3-phase helical CT, and conventional angiography. Contrast-enhanced sonographic and CT findings were interpreted separately and prospectively for the presence or absence of contrast enhancement in the treated HCCs. Conventional angiography served as the reference standard. RESULTS: Intratumoral enhancement was seen in 19 HCCs (61%) on contrast-enhanced sonography and 12 HCCs (39%) on CT. Enhancement patterns on sonography were blush in 8 (42%), branching in 2 (11%), nodular in 4 (21%), and stippled in 5 (26%). Of the 19 HCCs with intratumoral enhancement on contrast-enhanced sonography, 13 (68%) showed tumor staining on angiography. Of the 12 HCCs without intratumoral enhancement on sonography, 1 (8%) showed tumor staining on angiography. The sensitivity and specificity of contrast-enhanced sonography in depicting flow in HCCs treated with TACE were 93% and 65%, respectively. The sensitivity and specificity of 3-phase CT were 64% and 100%. CONCLUSIONS: Contrast-enhanced sonography is a more sensitive imaging method than 3-phase CT in depicting vascularity in HCCs treated with TACE.     

Real-time imaging with the sonographic contrast agent SonoVue: differentiation between benign and malignant hepatic lesions.

OBJECTIVE: We investigated the ability of contrast-enhanced sonography with SonoVue (Altana Pharma, Konstanz, Germany), a sulfur hexafluoride microbubble contrast agent, to reveal differences between benign and malignant focal hepatic lesions. METHODS: One hundred twenty-six lesions in 124 patients with focal hepatic lesions detected by B-mode sonography (hepatocellular carcinoma, n = 36; metastasis, n = 25; cholangiocellular carcinoma, n = 1; lymphoma, n = 2; focal nodular hyperplasia, n = 9; adenoma, n = 4; regenerative cirrhotic nodule, n = 13; hemangioma, n = 29; and focal hyposteatosis, n = 7) were examined in a prospective study. After intravenous injection of 2.4 mL of SonoVue, the liver was examined continuously for 3 minutes by low-mechanical index pulse inversion sonography. RESULTS: For the discrimination of malignant versus benign liver lesions, SonoVue-enhanced sonography improved sensitivity from 78% to 100% and specificity from 23% to 92% compared with baseline sonography. Receiver operating characteristic analysis revealed a significant improvement in this discrimination (area under the receiver operating characteristic curve, 0.510 +/- 0.054 [SD] at baseline sonography, 0.998 +/- 0.003 with SonoVue-enhanced sonography; P < .001). The following flow patterns in the early phase were diagnosis specific: early central starlike pattern for focal nodular hyperplasia, peripheral globular-nodular pattern for hemangioma, and diffuse arterial enhancement for malignant lesions. Homogeneous enhancement in the late phase was predictive for benign lesions (P < .001). Conversely, 93% of patients without contrast enhancement in the late phase had malignant lesions (P < .001). CONCLUSIONS: SonoVue-enhanced sonography has greater specificity and sensitivity than baseline sonography for the differentiation of benign and malignant liver lesions.     

Blunt hepatic trauma: evaluation with contrast-enhanced sonography: sonographic findings and clinical application.

OBJECTIVE: The purpose of this study was to report our initial experience in the assessment of liver trauma with real-time contrast-enhanced sonography (CES). METHODS: From January 2000 to December 2003, there were 431 hemodynamically stable patients evaluated with sonography for blunt abdominal trauma. Among these patients, 87 were selected to undergo second-level imaging, consisting of CES and computed tomographic (CT) evaluation. Indications for further assessment were baseline sonographic findings positive for liver injury, baseline sonographic findings positive for injury to other abdominal parenchyma, baseline sonographic findings positive for free fluid only, baseline sonographic findings indeterminate, and baseline sonographic findings negative with persistent clinical or laboratory suspicion. RESULTS: There were 23 hepatic lesions shown by CT in 21 patients. Peritoneal or retroperitoneal fluid was identified in 19 of 21 positive cases by all 3 imaging modalities. Liver injury was found in 15 patients on sonography and in 19 on CES. Contrast-enhanced sonography compared better than unenhanced sonography with the criterion standard for related injury conspicuity, injury size, completeness of injury extension, and involvement of the liver capsule. Both CES and CT showed intrahepatic contrast material pooling in 2 cases. All patients with false-negative sonographic or CES findings recovered uneventfully. CONCLUSIONS: Contrast-enhanced sonography is an effective tool in the evaluation of blunt hepatic trauma, being more sensitive than baseline sonography and correlating better than baseline sonography with CT findings. In institutions where sonography is regarded as the initial procedure to screen patients with trauma, this technique may increase its effectiveness. In addition, CES may be valuable in the follow-up of patients with conservatively treated liver trauma.     

Detection and differential diagnosis of hepatic masses using pulse inversion harmonic imaging during the liver-specific late phase of contrast enhancement with Levovist

PURPOSE: The purpose of this study was to investigate whether late-phase pulse inversion harmonic imaging (PIHI) increases conspicuity in hepatic masses, helps to differentiate benign from malignant lesions, and demonstrates a greater number of and smaller metastatic lesions than do conventional (fundamental) sonography and helical CT. METHODS: Thirty patients (17 women and 13 men; age range, 35-77 years; mean age, 54 years) with known or suspected liver masses were evaluated using both fundamental sonography and contrast-enhanced PIHI during the liver-specific late phase of Levovist. The patients also underwent contrast-enhanced triphasic helical CT examinations within 1 week after sonography. In 4 of the patients, gadolinium-enhanced MRI was also performed as a part of their clinical work-up. RESULTS: The increase in the lesions' conspicuity on PIHI compared with fundamental sonography was significantly greater in malignant lesions than in benign lesions (p< 0.001). An echogenic rim was observed on PIHI in 8 (53%) of 15 malignant lesions. The mean number of metastatic lesions visualized on PIHI (5.5 +/- 5.3) was significantly higher than the mean number visualized on fundamental sonography (2.5 +/- 2.1, p < 0.05). Although lesions as small as 3 mm were observed on PIHI, the mean sizes of the smallest lesions demonstrated using fundamental sonography, PIHI, and helical CT were not significantly different. CONCLUSIONS: Late-phase PIHI is a useful technique for characterizing hepatic lesions and demonstrating both a greater number of and smaller metastases. It may help to differentiate benign from malignant liver masses and may obviate unnecessary and expensive further imaging.     

Unusual benign focal liver lesions: findings on real-time contrast-enhanced sonography.

OBJECTIVE: This presentation aims to provide an overview of the manifestations of some unusual benign focal liver lesions (FLLs) on low-acoustic power contrast-enhanced sonography (CES) with a sulfur hexafluoride contrast agent. METHODS: The patients were selected retrospectively from 2209 cases with FLLs who had undergone CES examinations for characterization during the past 3 years. The pathologic examinations proved that they were intrahepatic biliary cystadenoma (n = 1), angiomyolipoma (AML; n = 4), lipoma (n = 1), biliary epithelial dysplasia (n = 1), a fungal inflammatory mass (n = 1), tuberculoma (n = 2), an inflammatory pseudotumor (n = 7), sarcoidosis (n = 1), solitary necrotic nodules (n = 2), peliosis hepatis (n = 2), and focal fibrosis after surgery (n = 4). RESULTS: Contrast-enhanced sonography was beneficial in leading to a diagnosis of benignity for some lesions showing hyperenhancement during the arterial phase and sustained enhancement during the portal or late phase, such as liver AML and lipoma. The benign nature of other lesions showing no enhancement during all phases, such as solitary necrotic nodules and focal fibrosis, was also suggestible. On the other hand, for those lesions showing hyperenhancement, isoenhancement, or hypoenhancement during the arterial phase and hypoenhancement during the late phase, including intrahepatic biliary cystadenoma, biliary epithelial dysplasia, infected liver diseases, the inflammatory pseudotumor, sarcoidosis, and peliosis hepatis, the differential diagnosis between benignity and malignancy was difficult, and pathologic tests were mandatory. CONCLUSIONS: The CES features of unusual benign FLLs may enrich knowledge when performing CES examinations for characterization and may provide clues for a specific diagnosis of an individual lesion such as liver AML.     

Contrast-enhanced power Doppler sonography of malignant ovarian tumors using harmonic flash-echo imaging: preliminary experience

To investigate the potential usefulness of contrast-enhanced intermittent harmonic sonography in the diagnosis of ovarian cancer, we evaluated 4 patients with complex adnexal masses suspected of malignancy using intermittent harmonic sonography after injection of a contrast agent. Tumor and/or mural nodule tissue enhancement was detected in all cases of ovarian malignancy. Contrast-enhanced, intermittent harmonic sonography provides a satisfactory visualization of blood flow in the solid portion of the tumor tissue and may support a diagnosis of ovarian malignancy. Depiction of blood vessels using low MI techniques may be possible with other vascular ultrasonographic contrast agents.     

Evaluation of lymph node perfusion using continuous mode harmonic ultrasonography with a second-generation contrast agent.

OBJECTIVE: To evaluate the contribution of continuous mode contrast-enhanced harmonic ultrasonography (CE-HUS) with a second-generation contrast agent to the characterization of superficial lymphadenopathies with respect to conventional ultrasonographic techniques (B-mode and power Doppler). METHODS: Fifty-six lymph nodes from 45 patients were studied both by conventional techniques and by CE-HUS. The dimensions, intranodal architecture, margins, and location of vessels were evaluated. Subsequently, all the lymph nodes were examined by CE-HUS, and enhancement of echogenicity was evaluated. The diagnoses obtained by means of fine-needle aspiration cytologic examination, surgical biopsy, or both were compared with those obtained by ultrasonography. RESULTS: Of the lymph nodes examined, 30 were benign and 26 were malignant (18 metastases and 8 non-Hodgkin lymphomas). The study using CE-HUS showed intense homogeneous enhancement in 28 of 30 reactive lymph nodes; perfusion defects in 17, of which 15 were neoplastic and 2 were inflammatory; intense but inhomogeneous speckled enhancement in the early arterial phase in 5 cases of lymphoma; and, last, scarce or absent intranodal enhancement in 4 metastases. The specificity, sensitivity, and accuracy of conventional techniques in differentiation between benign and malignant lymph nodes were 76%, 80%, and 78% versus 93%, 92%, and 92.8% for CE-HUS. The increase in correct diagnoses was significant (P = .05) when conventional ultrasonography was tested against CE-HUS. CONCLUSIONS: Superficial lymph nodes can be characterized as being neoplastic or benign with a high degree of diagnostic accuracy on the basis of the perfusion characteristics evaluated by CE-HUS. This technique has been shown to afford a higher degree of accuracy than currently obtainable by any other ultrasonographic technique.     

Early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma: utility of gray scale harmonic ultrasonography with a microbubble contrast agent.

OBJECTIVE: To evaluate the utility of gray scale harmonic ultrasonography with a microbubble contrast agent in the early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma. METHODS: Seventy-five patients with 81 nodular hepatocellular carcinomas (1.3-4.8 cm) treated with percutaneous radio frequency ablation were evaluated with contrast-enhanced gray scale harmonic ultrasonography after intravenous bolus injection of a galactose-based microbubble contrast agent. The vascularity within the ablation zones was evaluated with a continuous scan for 3 to 5 seconds between 15 and 30 seconds after initiation of contrast agent injection. To evaluate the perfusion of the ablation zones, intermittent stimulated acoustic emission imaging was performed with a rapid sweeping technique from the end of the continuous scan. All patients underwent follow-up 3-phase helical computed tomography at 1 month after radio frequency ablation and were followed for at least 1 year. The results of contrast-enhanced ultrasonography were compared with those of follow-up computed tomography in terms of the presence or absence of residual unablated tumors. RESULTS: In 10 (12%) of the 81 treated hepatocellular carcinomas, contrast-enhanced ultrasonography showed either nodular or crescentic enhancing foci at the margins of ablation zones, suggesting residual unablated tumors. Contrast-enhanced computed tomography obtained 1 month after radio frequency ablation confirmed the residual unablated tumors in the same 10 lesions. Diagnostic agreement between 1-month follow-up computed tomography and contrast-enhanced ultrasonography was achieved in all 81 cases (100%). CONCLUSIONS: Contrast-enhanced gray scale harmonic ultrasonography can be a reliable alternative to contrast-enhanced computed tomography in the early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma.     

Characterization of small focal liver lesions using real-time contrast-enhanced sonography: diagnostic performance analysis in 200 patients.

OBJECTIVE: The purpose of this study was to assess the diagnostic performance of real-time contrast-enhanced sonography in characterization of small focal liver lesions (FLLs; < or = 3.0 cm in diameter). METHODS: Two hundred small FLLs in 200 patients were examined by contrast-enhanced sonography using a contrast-specific mode of contrast pulse sequencing and a sulfur hexafluoride-filled microbubble contrast agent. The sonographic images were reviewed by 2 independent readers. A 5-point confidence level was used to discriminate malignant from benign FLLs, and specific diagnoses were recorded. The diagnostic performances were evaluated by receiver operating characteristic (ROC) analysis, and the interobserver agreement was analyzed by weighted kappa statistics. RESULTS: After review of contrast-enhanced sonography, ROC analysis revealed significant improvement in differentiating between malignant and benign small FLLs that the areas under the ROC curve were 0.856 at baseline sonography versus 0.954 at contrast-enhanced sonography for reader 1 (P < .001) and 0.857 versus 0.954 for reader 2 (P = .003). The sensitivity, negative predictive value, and accuracy for both readers also improved significantly after contrast agent administration (all P < .001). A better result of specific diagnosis was obtained (38.5% [77/200] at baseline sonography versus 80.5% [161/200] at contrast-enhanced sonography for reader 1 and 34.5% [69/200] versus 80.5% [161/200] for reader 2; both P < .001) after contrast agent administration, and a better interobserver agreement was achieved (kappa = 0.425 at baseline sonography versus 0.716 at contrast-enhanced sonography). CONCLUSIONS: Real-time contrast-enhanced sonography improves the diagnostic performance in small FLLs compared with baseline sonography.     

Contrast-enhanced Doppler perfusion index: clinical and experimental evaluation.

OBJECTIVE: To assess the potential of the power Doppler signal intensity rate of enhancement due to contrast agent wash-in for assessment of hepatic hemodynamics. METHODS: With the use of standardized settings, power Doppler sonography was performed before and after administration of a contrast agent. Video-recorded examinations were digitized for offline analysis on a personal computer. The temporal changes of the power Doppler signal intensity were quantified to provide contrast agent wash-in curves. The contrast-enhanced Doppler perfusion index was defined by the ratio of the wash-in gradient of the hepatic artery and portal vein as contrast-enhanced Doppler perfusion index = hepatic artery gradient/(hepatic artery gradient + portal vein gradient). The contrast-enhanced Doppler perfusion index was evaluated at 4 contrast agent doses in each of 14 patients with liver metastases and 3 patients with hemangiomas. An in vitro flow model was used to determine the relationships between the power Doppler rate of enhancement and flow in vessels of 4, 8, and 12 mm in diameter. RESULTS: In vivo, there was a significantly higher (P < .0001) mean contrast enhanced Doppler perfusion index in patients with liver metastases (mean, 0.59; 95% confidence interval, 0.54-0.63), compared with patients with hemangiomas (mean, 0.33; 95% confidence interval, 0.24-0.41). The corresponding coefficients of variations were 25% for patients with liver metastases and 31% for patients with hemangiomas. In vitro, the power Doppler rate of enhancement was proportional to flow speed and independent of vessel diameter. CONCLUSIONS: Measurement of the contrast-enhanced Doppler perfusion index may have potential in assessment of hepatic hemodynamics and focal liver disease.     

Evaluation of contrast enhancement patterns in pancreatic tumors by coded harmonic sonographic imaging with a microbubble contrast agent.

OBJECTIVE: The purpose of the study was to assess patterns of primary pancreatic lesions by contrast-enhanced sonography for differentiating ductal carcinomas from other pancreatic tumors. METHODS: One hundred six consecutive patients with pancreatic masses, consisting of 83 ductal carcinomas, 7 endocrine carcinomas, 5 intraductal papillary mucinous tumors, 3 cases of autoimmune-related pancreatitis, 3 solid pseudopapillary tumors, 2 cases of chronic pancreatitis, 1 serous cystadenoma, 1 osteoclastoid giant cell tumor, and 1 follicular lymphoma, were examined by contrast-enhanced sonography with coded harmonic imaging in a phase inversion harmonic technique. The contrast enhancement patterns were assessed, and specimens removed during pancreatectomy were subjected to pathologic examination. RESULTS: Internal tumoral vascularity was detected in 47 (56.6%) of the 83 ductal carcinomas. Vascular image spreading and homogeneous staining throughout the tumors were observed in all endocrine carcinomas. Two of the 5 intraductal papillary mucinous tumors were positive for enhancement effects. Enhancement effects were observed in all 3 cases of autoimmune-related pancreatitis, but the degree varied. There was a significant correlation between the intensity of enhancement effects and the ratio of patent vessels in the tumors (P < .05). CONCLUSIONS: Vascularity was detected by contrast-enhanced sonography in only about half of the ductal carcinomas, confirming the difficulty in distinguishing those tumors from other pancreatic tumors. There was a correlation between the patency of the vessels in the tumors and their vascularity.