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At least 613 records · Page 34Linked to original sources
PubMed2001

Do different types of liver lesions differ in their uptake of the microbubble contrast agent SH U 508A in the late liver phase? Early experience.

PURPOSE: To compare the uptake of SH U 508A in different types of liver lesions by using stimulated acoustic emission. MATERIALS AND METHODS: Thirty-seven patients with characterized lesions (metastasis, n = 17; hepatocellular carcinoma, n = 4; hemangioma, n = 9; focal nodular hyperplasia, n = 7) received 2.5 g SH U 508A. After 5 minutes, stimulated acoustic emission was elicited by using a previously described method. Liver and/or lesional differences were assessed with videodensitometry (objective conspicuity score), and two observers assessed each lesion by using a six-point scale (subjective conspicuity score). RESULTS: Metastases and hepatocellular carcinoma had low stimulated acoustic emission; median objective conspicuity scores were 70% and 68% (all scores were > or =43%), respectively, and subjective conspicuity scores were 2 or higher for both observers. Hemangiomas had reduced stimulated acoustic emission, with more variability; the median objective conspicuity score was 41% (range, 9%-72%), and the median subjective conspicuity scores were 2 (range, 1-4) and 3.5 (range, 1-5) for observers 1 and 2, respectively. Focal nodular hyperplasia had stimulated acoustic emission comparable to that of the liver in all cases; the median objective conspicuity score was -4.7% (all scores were <6%), and the subjective conspicuity score was 1 or lower for both observers. This finding completely separated focal nodular hyperplasia and malignancies. Significant differences were seen between focal nodular hyperplasia and all other lesion types (P < .05). CONCLUSION: Strong late-phase lesional uptake of SH U 508A is characteristic of focal nodular hyperplasia, is seen in some hemangiomas, and was not observed in malignancies.

Adult↗
PubMed2005

Bolus versus continuous infusion of microbubble contrast agent for liver US: initial experience.

Institutional review board approval and informed consent were obtained. To prospectively assess if continuous infusion of galactose-palmitic acid can prolong the duration of hepatic enhancement at ultrasonography over bolus injection, 11 patients received two injections--one bolus injection (2 mL/sec) and one continuous infusion (1.5 mL/min)--with the same dose of galactose-palmitic acid (4 g, 300 mg/dL). Two unenhanced baseline sweep scans (mechanical index of 0.7 and 1.3) of the relevant liver lobe were acquired followed by contrast-enhanced sweeps after bolus injection and continuous infusion. Each sweep was saved as cine loops and analyzed with a personal computer. Duration of enhancement more than 3 dB was prolonged by continuous infusion from 4.3 minutes +/- 2.4 (+/-standard deviation) at bolus injection to 10.1 minutes +/- 3.0 (P < .005). Maximal parenchymal enhancement was 11.0 dB +/- 3.2 (bolus injection) and 9.2 dB +/- 3.8 (infusion, P < .05). Peak liver-to-lesion contrast was 14.2 dB +/- 6.3 (bolus injection) and 13.2 dB +/- 7.1 (infusion, not significant). Continuous infusion of galactose-palmitic acid markedly prolongs but slightly diminishes hepatic enhancement; liver-to-lesion contrast remains unchanged.

Adult↗
PubMed1999

Radio-frequency ablation of hepatic metastases: postprocedural assessment with a US microbubble contrast agent--early experience.

PURPOSE: To evaluate contrast agent-enhanced ultrasonography (US) in the detection of untreated tumor after radio-frequency (RF) ablation of hepatic metastases. MATERIALS AND METHODS: Twenty patients with solitary colorectal liver metastases underwent percutaneous RF tumor ablation. Pre- and postablation imaging was performed with nonenhanced and enhanced color and power Doppler US and contrast-enhanced helical computed tomography (CT). Initial follow-up CT and US were performed 24 hours after ablation. The findings at US and CT were compared. RESULTS: Nonenhanced US demonstrated intratumoral signal in 15 of 20 metastases before ablation. This signal increased after contrast agent administration. Contrast-enhanced US performed 24 hours after ablation demonstrated residual foci of enhancement in three tumors, whereas no US signals were seen in any tumor on nonenhanced scans. CT demonstrated small (< 3-mm) persistent foci of residual enhancement in these three tumors and in three additional lesions that were not seen at US (US sensitivity, 50%; specificity, 100%; diagnostic agreement with CT, 85%). All six patients with evidence of residual tumor underwent repeat RF ablation. CONCLUSION: Contrast-enhanced US may depict residual tumor after RF application and thereby enable additional directed therapy. The potential reduction in treatment sessions and/or ancillary imaging procedures might increase the ease and practicality of percutaneous ablation of focal hepatic metastases.

Aged↗
PubMed2001

Contrast microbubbles improve diagnostic yield in ICU patients with poor echocardiographic windows.

OBJECTIVE: To determine the value of contrast echocardiographic studies in patients admitted to ICUs who have poor echocardiographic windows secondary to COPD, ventilator use, or inability to obtain optimal positioning for the echocardiogram. DESIGN: A prospective comparison study of technically difficult patients in the ICU. OUTCOME MEASURE: The total scores for the left ventricle (LV) in the two-chamber and four-chamber views were calculated at baseline and following injection of 1 to 2 mL of a contrast agent. The mean numbers of segments visualized in all patients at baseline and after injection of contrast agent were compared to assess the effect on improved visualization. RESULTS: Forty consecutive patients underwent echocardiography in the ICU for evaluation of LV function. Of these, 25 patients (63%) had poor visualization of the endocardium and required IV contrast agent. In these 25 patients, the average baseline segmental score was 4.5, compared to 11.6 in patients who received an IV contrast agent. Nineteen patients had an average baseline segmental score of 3.9 and were deemed to have a nondiagnostic study. After administration of IV contrast, all patients converted to a diagnostic study, with an average score of 11.6 segments visualized. CONCLUSIONS: Use of echocardiographic contrast agents in selected patients with poor baseline echocardiographic windows in the ICU setting significantly enhances segmental LV visualization and yielded 100% conversion from nondiagnostic to diagnostic studies.

Adult↗
PubMed2003

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.

Adenocarcinoma↗
PubMed2004

Differentiation between benign and malignant hepatic lesions: utility of color stimulated acoustic emission with the microbubble contrast agent Levovist.

OBJECTIVE: This study was undertaken to determine whether the examination of color stimulated acoustic emission in the late phase of Levovist (SH U 508A; Schering AG, Berlin, Germany) enhancement is helpful in the discrimination between benign and malignant liver lesions. METHODS: Fifty-six patients with focal hepatic lesions were examined. Diagnosis of the lesions was confirmed by liver biopsy, computed tomography, or scintigraphy. Thirty-one patients had malignant liver lesions: hepatocellular carcinoma (n = 14), cholangiocellular carcinoma (n = 1), metastasis (n = 14), and lymphoma (n = 2). Twenty-five patients had benign lesions: focal nodular hyperplasia (n = 8), hepatic adenoma (n = 1), focal hyposteatosis or hypersteatosis (n = 6), hemangioma (n = 7), and regenerative cirrhotic nodules (n = 3). After a delay of 5 to 10 minutes without scanning, the liver was examined by color stimulated acoustic emission with a fast sweep of 1 to 3 seconds. RESULTS: All patients with homogeneous color stimulated acoustic emission in the late phase of Levovist enhancement had benign liver lesions (P < .001; specificity, 100%; sensitivity, 68%; positive predictive value, 100%; and negative predictive value, 79%). Eighty-one percent of the patients with nonenhancing lesions in the late phase surrounded by enhanced liver parenchyma had malignant liver lesions (P < .001; specificity, 72%; sensitivity, 94%; positive predictive value, 81%; and negative predictive value, 90%). Interobserver agreement (weighted kappa value) improved from 0.570 +/- 0.038 for baseline sonography to 0.918 +/- 0.028 for color stimulated acoustic emission sonography. The area under the receiver operating characteristic curves for color stimulated acoustic emission sonography (0.927) was significantly higher than for baseline sonography (0.739; P < .05). CONCLUSIONS: Color stimulated acoustic emission in the late phase of Levovist enhancement has a high specificity and sensitivity for differentiation between benign and malignant focal liver lesions.

Analysis of Variance↗
PubMed1986

In vivo microbubble detection in decompression sickness using a second harmonic resonant bubble detector.

A resonant bubble detection method based on a second harmonic technique has been used to monitor the femoral vascular system of dogs subjected to rapid decompression. For this study, the detector consisted of two acoustic transducers mounted at right angles to each other that were packaged in a perivascular cuff configuration. This detector responds selectively only to bubbles near resonant size (4.2 mum in diameter); solid particles and large bubbles produce no response. The detector was used to monitor a total of 15 dogs. Eleven dogs were subjected to a series of simulated underwater dives until acute symptoms of decompression sickness occurred; 4 dogs served as controls. In the dived group, either the femoral vein or the femoral artery was monitored. Resonant bubbles were observed in the femoral veins of all 6 dogs monitored at this location. During arterial monitoring, most dogs showed no response, but an occasional weak response was observed in 2 of the dogs. No resonant bubbles were detected in the femoral artery or the femoral vein in any of the controls. The data suggest that this bubble detection method is feasible for in vivo use. Furthermore, 4 mum diameter bubbles are much more prevalent in the veins of dogs suffering from decompression sickness than they are in dog arteries, presumably because they are filtered out effectively by the pulmonary circulation. Modifications of this method are discussed to enhance its accuracy and applicability for quantifying bubble size, location, and number.

Animals↗