Characterization of focal liver lesions in real time using harmonic imaging with high mechanical index and contrast agent levovist

OBJECTIVE: The aim of this study was to characterize focal hepatic lesions using agent detection imaging and Levovist. MATERIALS AND METHODS: Sixty-five patients (21 male and 44 female; age range, 8-82 years; mean +/- standard deviation, 58.1 +/- 14.5 years) were independently evaluated by two observers in a blinded manner using stored sonographic images. Seventy-five lesions were found: 15 hepatocellular carcinomas, nine focal nodular hyperplasias, two adenomas, 21 hemangiomas, 23 metastases, and five regenerative nodules. Nine patients were excluded (six because of technical failures, three with unproven diagnoses). New high-mechanical-index software was used to reveal power harmonic responses from contrast microbubble destruction. After a venous bolus injection of 4 g of Levovist at a strength of 400 mg/mL, delayed imaging was used to study lesion enhancement in the arterial, portal, and parenchymal phases. Two comparisons were made. The first was between the B-mode image and the first contrast-enhanced image after the flash. The second was between color Doppler sonograms and real-time contrast-enhanced perfusion images. RESULTS: Contrast-enhanced images after the flash and real-time contrast-enhanced images revealed more information for the characterization of the lesion than did gray-scale and color Doppler images (p < 0.0001, Wilcoxon's signed rank test). Different types of lesions showed statistically significant differences in enhancement during each of the three vascular phases (p < 0.005, Kruskal-Wallis test). Lesions with lower contrast enhancement were metastases and regenerating nodules. Good agreement was present between the two observers; differences were not statistically significant (p > 0.05). CONCLUSION: Agent detection imaging with Levovist increased diagnostic confidence in the characterization of focal hepatic lesions as compared with standard sonography.     

Late-phase pulse-inversion sonography using the contrast agent levovist: differentiation between benign and malignant focal lesions of the liver

OBJECTIVE: We assessed the ability of contrast-enhanced sonography to reveal differences between benign and malignant focal hepatic lesions. SUBJECTS AND METHODS: We examined 67 patients with focal hepatic lesions in a prospective study. The causes of the lesions were confirmed by histology, CT, MR imaging, or scintigraphy. The liver was screened for focal lesions using sonography. Thereafter, 2 g of Levovist (300 mg/mL; 1 mL/sec) was injected IV as a bolus. After a delay of at least 2.5 min without scanning, the liver was examined via three different scans using pulse-inversion sonography. RESULTS: For the discrimination of malignant versus benign liver lesions, contrast-enhanced sonography improved sensitivity from 85% to 100% and specificity from 30% to 63%, as compared with baseline sonography. Receiver operating characteristic analysis revealed a significant improvement in this discrimination (A(z) = 0.692 +/- 0.065 at baseline sonography, A(z) = 0.947 +/- 0.037 with contrast-enhanced sonography, p < 0.001). Furthermore, a lower interobserver variability was found for contrast-enhanced sonography (weighted kappa = 0.947), as compared with baseline sonography (weighted kappa = 0.469). All lesions that had homogeneous enhancement in the late phase of Levovist enhancement were benign. In distinction, 90% of lesions without contrast enhancement in the late phase were malignant. All lesions were malignant that were isoechoic (invisible) on baseline sonography but visible because of lack of enhancement after injection. CONCLUSION: Contrast-enhanced sonography has greater specificity and sensitivity than baseline sonography for the differentiation of benign and malignant liver lesions.     

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.     

超声造影诊断肝脏局灶性结节状增生的价值

目的：探讨超声造影诊断肝脏局灶性结节状增生的价值。材料和方法：回顾分析了11例肝脏局灶性结节状增生的超声造影表现。9例于造影后经超声引导穿刺确诊,2例经手术确诊。结果：11例病灶动脉期均快速显著增强。9例病灶动脉早期呈轮辐状增强,造影三期回声强于周边肝实质,实质期可见轮辐状低回声；2例病灶动脉早期快速增强,动脉期及门脉期回声强于周边肝实质,实质期回声与肝实质等同,未见轮辐状低回声。结论：超声造影所显示的肝脏局灶性结节状增生的增强特征,有助于临床诊断。部分病灶超声造影表现缺乏特异性,确诊仍需要结合其他影像学方法和穿刺活检。     

Comparison of diagnostic performance of unenhanced vs SonoVue - enhanced ultrasonography in focal liver lesions characterization. The experience of three Italian centers

PURPOSE: To evaluate the diagnostic performance of contrast-enhanced US with SonoVue (Bracco, Milan, Italy) compared to baseline US in focal hepatic lesions characterization. MATERIALS AND METHODS: A comprehensive number of four operators from 3 hospitals evaluated 57 consecutive patients with 60 focal hepatic lesions (28 hepatocellular carcinomas, 11 metastases, 13 hemangiomas, 1 hepatocellular adenoma and 7 focal nodular hyperplasias) by baseline gray-scale ultrasound (US) and color Doppler US. The same lesions were subsequently scanned by contrast-enhanced US after intravenous bolus administration of 2,4-4,8 ml of SonoVue by employing intermittent high or continuous low transmit power imaging. The diagnosis of lesions nature (benign or malignant) and histotype proposed by the on-site operator was finally compared to the definite diagnosis reached by reference procedures (multiphasic contrast-material enhanced helical-computed tomography or magnetic resonance in 24 lesions and fine needle US guided biopsy in 36 lesions). Diagnostic performance (sensitivity, specificity and overall accuracy expressed by the agreement with the reference procedures) of baseline and contrast enhanced US were compared. RESULTS: Differences in sensitivity (baseline vs contrast-enhanced US: 13/39 [33%] vs 32/39 [82%]), specificity (baseline vs contrast-enhanced US: 12/21 [57%] vs 16/21 [76%]) and overall accuracy (baseline vs contrast-enhanced US: 25/60 [41%] vs 47/60 [78%]) were significant (p<0.05; McNemar test). CONCLUSIONS: SonoVue-enhanced US determined a significant improvement in diagnostic performance in the characterization of focal liver lesions if compared to baseline US.     

Clinical value of MRI liver-specific contrast agents: a tailored examination for a confident non-invasive diagnosis of focal liver lesions

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.     

Phase-inversion sonography during the liver-specific late phase of contrast enhancement: improved detection of liver metastases

OBJECTIVE: The purpose of our study was to assess whether phase-inversion sonography during the late, liver-specific phase of contrast enhancement using Levovist improves the detection of hepatic metastases relative to unenhanced conventional B-mode sonography. SUBJECTS AND METHODS: Sixty-two patients were studied with unenhanced B-mode sonography and phase-inversion sonography 2.5 min after the injection of Levovist. All patients underwent one reference examination (CT, MR imaging, or intraoperative sonography). The conspicuity, number, size, and distribution of metastases before and after contrast administration as judged by a sonographer (who was unaware of other imaging findings) were compared with each other and with reference imaging. RESULTS: The conspicuity of metastases was improved by contrast-enhanced phase inversion in 94% of patients. Thirty-nine patients showed metastases on reference imaging; 36 of these were positive on baseline sonography and 38 on phase-inversion sonography. Phase-inversion sonography showed more reference imaging-confirmed metastases than baseline sonography in 28 patients (45%). The average number of confirmed metastases per patient was 3.06 for baseline sonography and 5.42 for contrast-enhanced phase-inversion sonography (p < 0.01). The average sensitivity for detecting individual metastases improved from 63% to 91%. Metastases of less than 1 cm were shown in 14 patients on baseline sonography, in 24 patients on phase-inversion sonography, and in 26 on reference imaging. Both sonographic techniques showed false-positive lesions in six patients. CONCLUSION: Contrast-enhanced phase-inversion sonography in the liver-specific phase of contrast enhancement using Levovist provides a marked improvement in the detection of hepatic metastases relative to unenhanced conventional sonography, without loss of specificity. Phase-inversion sonography was particularly advantageous in detecting small metastases and may be a competitive alternative to CT and MR imaging.     

Evaluation of the accuracy of gadobenate dimeglumine-enhanced MR imaging in the detection and characterization of focal liver lesions

OBJECTIVE. We evaluated the extent to which hepatic lesion characterization and detection is improved by using gadobenate dimeglumine for enhancement of MR images. MATERIALS AND METHODS. Eighty-six patients were imaged before gadobenate dimeglumine administration, immediately after the 2 mL/sec bolus administration of a 0.05 mmol/kg dose (dynamic imaging), and at 60-120 min after the IV infusion at 10 mL/min of a further 0.05 nmol/kg dose (delayed imaging). The accuracy for lesion characterization was assessed for a total of 107 lesions. Sensitivity for lesion detection was assessed for a total of 149 lesions detected on either intra-operative sonography, iodized oil CT, CT during arterial portography, or follow-up contrast-enhanced CT as the gold standard. RESULTS. The accuracy in differentiating benign from malignant liver lesions increased from 75% and 82% (the findings of two observers) on unenhanced images alone, to 89% and 80% on dynamic images alone (p<0.001, p = 0.8), and to 90.7% when combining the unenhanced and dynamic image sets (p<0.001, p = 0.023). Delayed images did not further improve accuracy (90% and 91%; p = 0.002, p< 0.05). A similar trend was apparent in terms of accuracy for specific diagnosis: values ranged from 49% and 62% on unenhanced images alone, to 76% and 70% on combined unenhanced and dynamic images (p<0.001, p = 0.06), and to 75% and 70% on inclusion of delayed images (p<0.001, p = 0.12). The sensitivity for lesion detection increased from 77% and 81% on unenhanced images alone, to 87% and 85% on combined unenhanced and dynamic images (p = 0.001, p = 0.267), and to 92% and 89% when all images were considered (p<0.001, p = 0.01). CONCLUSION. Contrast-enhanced dynamic MR imaging with gadobenate dimeglumine significantly increases sensitivity and accuracy over unenhanced imaging for the characterization of focal hepatic lesions, and delayed MR imaging contributes to the improved detection of lesions.     

Initial experience with contrast-enhanced sonography of the prostate

OBJECTIVE: We investigated the usefulness of contrast-enhanced sonography to depict vascularity in the prostate and improve the detection of prostatic cancer. SUBJECTS AND METHODS: Twenty-six patients with an elevated prostate-specific antigen level (> or = 4 ng/ml) or an abnormal digital rectal examination were enrolled in a phase II study of an i.v. injected sonographic contrast agent. Continuous gray-scale, intermittent gray-scale, phase inversion gray-scale, and power Doppler sonography of the prostate were performed. Sonographic findings were correlated with sextant biopsy results. RESULTS: After the administration of contrast material, gray-scale and Doppler images revealed visible enhancement (p < 0.05). Using intermittent imaging, we found focal enhancement in two isoechoic tumors that were not visible on baseline images. No definite focal area of enhancement was identified in any patient without cancer. Contrast-enhanced images revealed transient hemorrhage in the biopsy tracts of three patients. CONCLUSION: Enhancement of the prostate can be seen on gray-scale and Doppler sonographic images after the administration of an i.v. contrast agent. Contrast-enhanced intermittent sonography of the prostate may be useful for the selective enhancement of malignant prostatic tissue.     

Contrast-enhanced versus conventional and color Doppler sonography for the detection of thrombosis of the portal and hepatic venous systems

OBJECTIVE: We conducted a prospective study to compare sonography, color Doppler sonography, and contrast-enhanced sonography for the detection and characterization of portal and hepatic vein thrombosis complicating hepatic malignancies. SUBJECTS AND METHODS: Three hundred sixteen patients with biopsy-proved hepatic tumors were studied at baseline and 3 months later with sonography, color Doppler sonography, and contrast-enhanced sonography. Thrombosis was defined as the presence of intraluminal echogenic material at sonography, absence of intraluminal color signals at color Doppler sonography, and presence of nonenhancing intraluminal area at contrast-enhanced sonography. Thrombi were considered malignant if they displayed continuity with tumor tissue at sonography, intrathrombus color signals at color Doppler sonography, and enhancing signals at contrast-enhanced sonography, both having arterial waveforms at Doppler spectral examination. Definitive diagnoses were obtained by sonographically guided biopsy except for thrombi displaying at conventional sonography unequivocal continuity with tumor tissue. RESULTS: Thrombosis was detected in 79 (25.0%) of 316 patients at baseline and in 83 (26.3%) of 316 patients after 3 months. Eighty-one (97.6%) of the 83 thrombi were malignant. Definitive diagnosis was performed by imaging in 60 (72.3%) of the 83 cases and by biopsy in 23 cases (27.7%). For thrombus detection, contrast-enhanced sonography displayed significantly higher sensitivity than color Doppler sonography (p = 0.004) and borderline superiority over sonography (p = 0.058). For thrombus characterization, contrast-enhanced sonography was significantly more sensitive than color Doppler sonography (p < 0.0005) and conventional sonography (p = 0.02). CONCLUSION: Contrast-enhanced sonography is superior to sonography and color Doppler sonography for the detection and characterization of portal and hepatic vein thrombosis complicating hepatic malignancies.     

Contrast-enhanced sonography with SonoVue: enhancement patterns of benign focal liver lesions and correlation with dynamic gadobenate dimeglumine-enhanced MRI

OBJECTIVE: Contrast-enhanced real-time low-mechanical-index sonography is a new diagnostic technique for the assessment of macro- and microcirculation. The purpose of our article is to describe contrast-enhancement patterns of different benign focal liver lesions using the second-generation contrast agent SonoVue and to compare these findings with those of gadobenate dimeglumine-enhanced MRI. CONCLUSION: SonoVue-enhanced real-time low-mechanical-index sonography provides specific contrast-enhancement patterns of different benign focal liver lesions, allowing accurate characterization. Findings on SonoVue-enhanced sonography correlate well with those obtained on gadobenate dimeglumine-enhanced MRI.     

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.     

Sonographic detection of hepatocellular carcinoma and dysplastic nodules in cirrhosis: correlation of pretransplantation sonography and liver explant pathology in 200 patients

OBJECTIVE: The objective of this study was to determine the sensitivity and specificity of sonography as an aid in detecting hepatocellular carcinomas and dysplastic nodules using explantation correlation in patients with cirrhosis and no known hepatocellular carcinomas. MATERIALS AND METHODS: The sonography reports of 200 patients with cirrhosis who underwent sonography and then underwent liver transplantation within 90 days were retrospectively reviewed for focal solid liver lesions. All focal solid masses detected on sonography were considered possible hepatocellular carcinomas. The sonographic findings were compared with thin-section explanted liver pathologic results. RESULTS: Twenty-seven patients (13.5%) had hepatocellular carcinoma at explantation, including four patients with diffuse, multifocal tumors. Eight of the 39 lesions were detected on sonography for a patient sensitivity of 29.6% and a lesion sensitivity of 20.5%. Sonography revealed three (75%) of four hepatocellular carcinomas larger than 5 cm in diameter, one (50%) of two hepatocellular carcinomas with diameters of 3.1-5.0 cm, one (20%) of five hepatocellular carcinomas with diameters of 2.1-3.0 cm, three (13.6%) of 22 hepatocellular carcinomas with diameters of 1-2 cm, and no lesions with diameters smaller than 1 cm. Forty-two patients (21%) had a total of 126 dysplastic nodules including two patients with innumerable lesions. Sonography depicted only two dysplastic nodules, for a patient sensitivity of 4.8% and a lesion sensitivity of 1.6%. The overall specificity of sonography for either hepatocellular carcinomas or dysplastic nodules was 96%. CONCLUSION: Sonography has low sensitivity but high specificity in revealing hepatocellular carcinomas and dysplastic nodules in patients with a cirrhotic liver requiring liver transplantation. In these patients, sonography should not be the sole imaging modality used for lesion detection before transplantation.     

Diagnostic accuracy of phase-inversion tissue harmonic imaging versus fundamental B-mode sonography in the evaluation of focal lesions of the kidney

OBJECTIVE: We compared phase-inversion tissue harmonic imaging with fundamental B-mode sonography in the evaluation of focal lesions of the kidney. SUBJECTS AND METHODS: For our prospective study, 114 patients underwent sonography of the kidneys in both modes, fundamental B-mode sonography and phase-inversion tissue harmonic imaging, in a randomly chosen scanning order. Imaging parameters were standardized. Sonographic diagnoses were made under real-time conditions by the examining radiologist. All sonographic diagnoses were compared with a diagnostic reference modality: contrast-enhanced CT, contrast-enhanced MR imaging, or histopathology. Three radiologists different from the examiners evaluated overall image quality, lesion conspicuity, and fluid-solid differentiation for both modalities using hard-copy images. RESULTS: In 70 patients, fundamental B-mode sonography as the first technique depicted 73 of 111 lesions 10 mm or larger and enabled 71 lesions to be correctly characterized (sensitivity, 65.8%; accuracy, 64.0%). As the first mode, phase-inversion tissue harmonic imaging depicted 57 of 65 focal lesions and enabled 54 lesions to be accurately classified in 44 patients (sensitivity, 87.7%; accuracy, 83.1%). The differences in sensitivity and accuracy were statistically significant (95% confidence interval). For overall image quality, lesion conspicuity, and fluid-solid differentiation phase-inversion harmonic imaging was superior to fundamental B-mode sonography (p < 0.0001). CONCLUSION: Phase-inversion tissue harmonic imaging is superior to fundamental B-mode sonography in the sonography of focal kidney lesions because phase-inversion tissue harmonic imaging has better overall image quality, lesion conspicuity, and fluid-solid differentiation. In six cases, phase-inversion tissue harmonic imaging added crucial diagnostic information that changed patient management.     

Ultrasound of focal liver lesions

This paper gives a comprehensive overview of ultrasound of focal liver lesions. Technical aspects such as examination technique and the use of Doppler modes as well as recent developments such as tissue harmonic imaging and microbubble contrast agents are discussed. The clinical significance and sonographic features of various liver lesions such as haemangioma, focal nodular hyperplasia, adenoma, regenerative nodule, metastasis, hepatocellular carcinoma and various types of focal infections are described. With the exception of cysts and typical haemangiomas, definitive characterisation of a liver lesion is often not possible on conventional ultrasound. This situation has changed with the recent advent of ultrasound contrast agents, which permit definitive diagnosis of most lesions. Contrast-enhanced sonography using recently developed contrast-specific imaging modes dramatically extends the role of liver ultrasound by improving its specificity in the detection and characterisation of focal lesions to rival CT and MRI.     

Benign liver lesions: implications of detection in cancer patients

A review of liver sonograms obtained for cancer patients (excluding primary liver cancers) over a 12 year period found 829 benign lesions: non-parasitic cysts (427 cases), hemangiomas (216 cases), solitary calcifications (79 cases), focal fatty infiltration (62 cases), and miscellaneous lesions (45 cases). These benign pathologies represented 41.8% of the focal hepatic lesions observed during this period in this population; hepatic metastases accounted for the remaining 58.2%. Marked female predilection was noted for the nonparasitic cysts, hemangiomas, and focal fatty infiltration; 63–78.7% of these lesions were solitary, and first-line imaging by US was sufficient for diagnosis of 66.1–98.2% of cases. Analysis of lesion evolution over more than 5 years revealed modifications in 17% of hemangiomas, 23.9% of nonparasitic cysts, and 75% of cases of focal fatty infiltration. Systematic pretherapy liver sonography can be proposed owing to the high frequency of benign liver lesions that can create diagnostic problems during follow-up of cancer patients. Correspondence to: J. N. Bruneton     

Characterization of hypoechoic focal hepatic lesions in patients with fatty liver: diagnostic performance and confidence of contrast-enhanced ultrasound

The objective of this study was to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) to characterize hypoechoic focal hepatic lesions (HFHL) in fatty liver (FL). A study group of 105 patients with FL and 105 HFHLs (52 malignant and 53 benign) underwent CEUS after SonoVue administration. Two blinded readers independently reviewed baseline ultrasound (US) and CEUS scans and classified each lesion as malignant or benign on a five-point scale of confidence, and recorded whether further imaging work-up was needed. Sensitivity, specificity, areas under the receiver operating characteristic (ROC) curve (A (z)), and interobserver agreement were calculated. We observed that the diagnostic confidence improved after reviewing CEUS scans for both readers (A (z)=0.706 and 0.999 and A (z)=0.665 and 0.990 at baseline US and CEUS, respectively; p<0.0001). Inter-reader agreement increased (weighted k=0.748 at baseline US vs. 0.882 at CEUS). For both readers, after CEUS, the occurrence of correctly characterized lesions increased (from 27/105 [27.5%] to 94/105 [89.5%], and from 19/105 [18.1%] to 93/105 [88.6%], respectively; p<0.0001) and the need for further imaging decreased (from 93/105 [88.6%] to 26/105 [24.8%], and from 96/105 [91.4%] to 40/105 [38.1%], respectively; p<0.0001). We conclude that CEUS improves the diagnostic performance of radiologists in the characterization of HFHLs in FL and reduces the need for further imaging work-up.     

Effectiveness of MR imaging in characterizing small hepatic lesions: routine versus expert interpretation

OBJECTIVE: The aim of our study was to compare the effectiveness of MR imaging characterization of small (相似文献   

Hepatic lesion detection and characterization: value of nonenhanced MR imaging, superparamagnetic iron oxide-enhanced MR imaging, and spiral CT-ROC analysis

PURPOSE: To determine the accuracy for detection and characterization of focal hepatic lesions of nonenhanced, superparamagnetic iron oxide (SPIO)-enhanced, or a combination of nonenhanced and SPIO-enhanced MR imaging and contrast-enhanced spiral computed tomography (CT). MATERIALS AND METHODS: Spiral CT and T2-weighted SPIO-enhanced (ferucarbotran-enhanced) MR imaging were performed in 35 patients within 2 weeks before surgery for malignant hepatic lesions. Only malignant lesions with histopathologic proof were considered. A total of 875 images with and 800 images without focal lesions were presented to five readers, who were asked to assess the presence and characterization of lesions by using a five-point confidence scale. Receiver operating characteristic analysis was performed. RESULTS: Nonenhanced and SPIO-enhanced images together and SPIO-enhanced images alone yielded the best performance for lesion detection. No differences were found among all imaging techniques with regard to lesion characterization (benign vs malignant). The combined approach resulted in larger area under the ROC curve (A(z) = 0.9062) and accuracy (85.3%) (P < 0.02), as compared with SPIO-enhanced MR imaging (A(z) = 0.8667; accuracy, 73.1%). CONCLUSION: SPIO-enhanced T2-weighted MR imaging was more accurate than nonenhanced T1-weighted and T2-weighted MR imaging and contrast-enhanced spiral CT for the detection of focal hepatic lesions. The combined analysis of nonenhanced and SPIO-enhanced images was more accurate in the characterization of focal hepatic lesions than was review of SPIO-enhanced images alone.     

Real-time contrast-enhanced ultrasound of the spleen: examination technique and preliminary clinical experience

PURPOSE: To report our preliminary experience in the evaluation of the spleen using a real-time contrast-specific ultrasound module in combination with a second-generation contrast agent. MATERIALS AND METHODS: In a 7-month period, 55 patients (34 males and 21 females, aged 5-77 years) with spleen disorders were evaluated by means of contrast-enhanced ultrasound. Two patients were studied because of baseline evidence of an accessory spleen and both underwent ultrasound follow-up. Twenty-five patients were studied for abdominal trauma and results were correlated with those of helical CT. Three patients were examined for suspected splenic infarction and for all CT correlation was obtained. Finally, twenty-five subjects were examined for focal diseases, such as lymphomas (17 cases) and focal lesions (8 cases); contrast-enhanced US results were correlated with those of CT (8 cases), MRI (2 cases), ultrasound follow-up (8 cases), biopsy (2 cases) or splenectomy (1 case). After an initial baseline study, the contrast-enhanced examinations were carried out using a dedicated unit equipped with a continuous contrast-specific module at low acoustic pressure. The examination started immediately after rapid contrast injection and lasted approximately 4 minutes. In the comparison between baseline and contrast-enhanced ultrasound, the following aspects were considered: detection rate of parenchymal changes, lesion extent (equal to CT, under- or overestimated), and lesion conspicuity (lesion-to-parenchyma gradient, from 0 = absent to 3 = high). RESULTS: In the 2 patients with accessory spleen, an enhancement very similar to that of the adjacent parenchyma was present and a small vascular pedicle was noted. Among the trauma patients, 18 had a direct splenic injury and one showed splenic contraction and hypoperfusion due to shock. In 74% of cases, a peritoneal effusion was demonstrated both with baseline and contrast-enhanced ultrasound; perisplenic blood collections (58% of cases) were identified in 42% of patients by both baseline and contrast-enhanced ultrasound; post-traumatic infarction was always revealed by contrast-enhanced ultrasound (11% of cases) but never by baseline ultrasound; parenchymal injuries were detected with a sensitivity of 63% by baseline ultrasound and a sensitivity of 89% by contrast-enhanced ultrasound. Moreover, contrast-enhanced ultrasound revealed findings undetectable on conventional ultrasound: global splenic hypoperfusion in 2 cases (due to shock in one and pedicle avulsion in the other), intraparenchymal contrast collections in 21% of positive cases (as confirmed by CT), extrasplenic contrast leakage in 1 of 2 cases demonstrated by CT. Of the 3 cases of splenic infarction, baseline sonography only only identified two, whereas the contrast-enhanced examination clearly identified three. Contrast-enhanced ultrasound revealed 35 of 39 focal lesions in patients studied for Hodgkin's disease and splenic focal lesions. Baseline ultrasound had a lower sensitivity (23 lesions). Lesion extension shown by contrast-enhanced sonography was equivalent to that provided by standard methods in 88% of cases (underestimated in 9% and overestimated in 3%); baseline US correctly estimated lesion size in 52% of cases, under- and overestimating them in 35% and 13% of cases, respectively. Lesion conspicuity was graded as 1 (low) in 16%, 2 (moderate) in 67%, and 3 (high) in 17% of the cases identified by enhanced sonography. Baseline ultrasound was less effective: conspicuity was graded as 1 in 42%, 2 in 39%, and 3 in 19% of cases. CONCLUSIONS: The spleen is the ideal organ to be studied with second-generation contrast media due to its superficial location, high vascularity, small size and homogeneous texture. Contrast-enhanced ultrasound is a simple, poorly-invasive and accurate tool for the evaluation of splenic disorders. If our data are confirmed, it will be possible to reduce the use of more complex technologies such as CT and MRI.