Real-time contrast enhanced ultrasound imaging of focal splenic lesions

Objective

To investigate the imaging features of focal splenic lesions (FSLs) on contrast-enhanced ultrasound (CEUS).

Methods

Thirty two patients with FSLs proved by pathology were retrospectively analyzed. CEUS was performed using intravenous bolus injection of 2.4 ml sulfur hexafluoride-filled microbubble contrast agent and real time scanning. There were hemangioma (n = 7), lymphoma (n = 8), true cyst (n = 3), infarction (n = 4), hematolymphangioma (n = 2), metastasis tumor (n = 2), and one for each of the following entities extramedullary hemopoiesis, hamartoma, tuberculosis, Langerhans’ cell histiocytosis, inflammatory pseudotumor and myxofibrosarcoma.

Results

Among 21 benign lesions, 4 infarctions and 3 cysts presented non-enhancement throughout CEUS scanning, and the other 14 lesions displayed various enhancement levels with 6 (42.9%) hyper-enhancement, 2 (14.3%) iso-enhancement and 6 (42.9%) hypo-enhancement in arterial phase and 11 (78.6%) hypo-enhancement, 1 (7.1%) iso-enhancement and 2 (14.3%) hyper-enhancement in late phase, respectively. The enhancement pattern included 9 (64.3%) homogeneous, 4 (28.6%) heterogeneous and 1 (7.1%) rim-like enhancement. As for the malignant FSLs, all the lesions became completely or extensively hypo-enhancement during the late phase no matter their vascularity during arterial phase.

Conclusions

The CEUS features reported in this series may enrich the knowledge for CEUS characterization of FSLs.     

Role of contrast enhanced ultrasound in characterization of focal liver lesions

Aim

The purpose of the study was to describe the enhancement patterns of focal liver lesions (FLLs) on contrast enhanced sonography (CEUS), assessing the potential of this technique for characterizing the lesions and to compare its diagnostic accuracy with conventional baseline sonography including color Doppler.

Materials and methods

Between August 2009 and July 2010, 50 patients with FLLs underwent gray scale sonography, color Doppler and CEUS. The enhancement patterns of these FLL’s were analyzed throughout the arterial phase, the portal venous phase and the extended portal venous phase (the late parenchymal phase). The final diagnosis was established on the basis of histopathologic examination or CT/MRI imaging.

Results

Out of these 50 FLLs, 33 were malignant (4 hepatocellular carcinoma and 29 metastasis) and 17 were benign (5 hemangioma, 5 abscess, 2 cyst and 1 each of FNH, focal fat sparing area, focal fatty infiltration, adenoma and benign/granulomatous lesion). The enhancement patterns after injecting microbubble contrast agent allowed characterization of FLLs. The malignant lesions showed intratumoral and/or peritumoral vascularity during the arterial phase and perfusion defect during the late parenchymal phase. Contrast enhanced sonography improved sensitivity in detecting malignancy (CEUS vs. baseline sonography, 100% vs. 81.8%).

Conclusion

CEUS improves detection and characterization of FLLs. It should be used as problem solving tool in cases where conventional gray scale and color Doppler sonography are non-diagnostic.     

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.     

Contrast enhanced ultrasound with second generation contrast agent in traumatic liver lesions

PURPOSE: To evaluate the accuracy of second generation contrast enhanced US (Sonovue) in the diagnosis and staging of traumatic hepatic lesions, compared with conventional US and spiral CT. MATERIAL AND METHODS: A total of 203 patients (127 males, 76 females, mean age 36 years) with isolated abdominal trauma were examined with conventional and contrast enhanced US (Sonovue, Bracco, Italy) between March 2002 and February 2003. The sonographic contrast agent was administered at a dose of 2 ml/10-15", repeated twice. CT examinations were performed with single- (Rhota, Esaote Biomedica, Italy) or multislice spiral CT with administration of contrast agent. The presence and number of lesions, hepatic capsular involvement, size and sonographic pattern were evaluated. RESULTS: Conventional US demonstrated hepatic lesions in 27 patients, in 3 cases it identified 2 foci (30 lesions, size 2-8 cm). Contrast enhanced US (CEUS) revealed another 2 lesions and in 4 patients it identified lesions not shown at conventional US (size 2-5 cm). Capsular involvement was detected in 14 cases (11 with conventional US). The sonographic pattern of the lesions at conventional US was hypo-anechoic in 19 cases, and hyperechoic in 11. In CEUS all the lesions appeared strongly hypoechoic against a strongly hyperechoic parenchyma, with clear borders and larger size as compared with conventional US. CONCLUSIONS: In isolated blunt abdominal trauma CEUS is more accurate than conventional US in determining the number and size of lesions and detecting capsular involvement. This has a strong impact on diagnosis as the number of false negatives is reduced and on prognosis as the lesions are more accurately graded, and there is close correlation with spiral CT. CEUS can be used as a first approach in mild isolated abdominal trauma, in paediatric patients and in the follow-up, whereas CT is the method of choice in severe trauma and in multiple traumas.     

菲立磁增强MRI对局灶性肝病的诊断价值:与螺旋CT对比的ROC曲线分析

目的 :对比分析菲立磁增强扫描与螺旋CT增强扫描对局灶性肝病的诊断价值。方法 :收集经本院完成螺旋CT增强扫描及菲立磁增强MRI扫描且临床、手术病理证实局灶性肝病 2 6例 5 7个病灶 ,采用分组盲法ROC曲线分析对比评价菲立磁增强MRI与螺旋CT增强扫描对局灶性肝病的诊断价值。结果 :联合分析平扫 +菲立磁增强MRI对病灶检出最好 ,与其它三组比较有显著性差异。对病灶定性 ,平扫 +菲立磁增强MRI组ROC曲线下面积Az 值最大为 0 92 6 0 ,准确性为 86 .8% ,差异有显著性 ,P <0 .0 5。螺旋CT增强扫描、MRI平扫及单独分析菲立磁MRI等三种方法之间差异无显著性 (P >0 .0 5 )。结论 :菲立磁增强MRI肝成像无论病灶的检出及定性诊断价值均高于螺旋CT增强扫描。联合分析平扫+菲立磁MRI较单独分析SPIO能明显改善病灶的检出能力及定性诊断能力。     

双源CT低管电压结合低浓度对比剂在肝脏增强扫描中的应用

【摘要】目的：探讨双源CT使用低管电压(100kVp)和低浓度等渗对比剂（270mg I/mL)进行肝脏增强扫描的可行性。方法：将我院108例行肝脏CT增强扫描的患者随机分成两组,每组54例。A组：管电压100kVp,对比剂为威视派克(270mg I/mL）。B组：管电压120kVp,对比剂为碘克沙醇(320mg I/mL）。测量、计算两组图像的对比噪声比（CNR）、信噪比（SNR）、肝实质CT值、肝动脉CT值、门静脉CT值及有效辐射剂量（ED）,并对两组图像进行主观评分,对两组间上述指标进行统计学分析。结果：A组的CNR高于B组,且差异具有统计学意义(t=2.88,P<0.05）,SNR高于B组(P<0.05）,A组能够提供清晰的诊断图像,提高病变的显示;A、B组的图像质量评分差异无统计学意义（t=-0.58,P>0.05）;A、B组的肝实质CT值及肝动脉CT值均无统计学差异(t=-1.81,P>0.05;t=0.96,P>0.05）,而A组的门静脉CT值高于B组（t=7.55,P<0.05);A组的三期总辐射剂量［（8.04±1.12）mSv］低于B组［(11.62±2.41)mSv］（t=9.94,P<0.001)。结论：双源CT肝脏增强扫描采用管电压100kVp和低浓度等渗对比剂(270mg I/mL）可以提供较好的图像CNR,提高门静脉CT值,保证诊断图像质量的同时降低辐射剂量。     

Characterization of focal liver lesions: comparative study of contrast-enhanced ultrasound versus spiral computed tomography

The purpose of this study was to compare the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) with spiral computed tomography (SCT) for the characterization of focal liver lesions (FLL) and to determine the degree of correlation between the two techniques. Seventy-seven FLL (45 hepatocellular carcinomas; 12 metastases; ten hemangiomas; two regenerating/dysplastic nodules; eight focal nodular hyperplasias) detected with ultrasound (US) were prospectively evaluated by CEUS using a second-generation contrast agent and SCT (with an interval of no more than one month between the two techniques). Independent observers made the most probable diagnosis and the results were compared with the final diagnoses (histology n = 59; MRI n = 18). Statistical analysis was performed by the Chi-square and Kappa tests. CEUS provided a correct, specific diagnosis in 69/77 (90%) of the FLL, while SCT did so in 67/77 (87%). The sensitivity, specificity, and diagnostic accuracy for malignancy were 91%, 90%, and 91%, respectively, for CEUS and 88%, 89%, and 88%, respectively, for SCT. No statistically significant difference was found between CEUS and SCT in the characterization of FLL (p > 0.05). In addition, agreement between the two imaging techniques was good (k = 0.75). We conclude that CEUS and SCT provide a similar diagnostic accuracy in the characterization of FLL, with a good degree of correlation between the two techniques.     

Characterisation of focal liver lesions with unenhanced and contrast enhanced low MI real time ultrasound: on-site unblinded versus off-site blinded reading

Objective

To compare on-site and blinded off-site reading of baseline ultrasound (US) and contrast enhanced ultrasound (CEUS) for classification and characterisation of focal liver lesions.

Materials and methods

99 patients (57 women and 42 men, age range 18–89 years, mean age: 59 years) with 53 malignant and 46 benign liver lesions were studied with unenhanced US followed by contrast enhanced US after injection of 2.4 ml SonoVue^® (Bracco, Milano, Italy). Image interpretation was performed on-site with clinical information available by consensus of two readers and off-site by two independent blinded readers at two different centers. Comparison of pre and post contrast scans and of the different readers was performed. Reference examinations were histology, intraoperative US, MRI or CT.

Results

Sensitivity for malignancy improved from 81/89/66% (on-site/off-site reader 1/2) before to 100/96/96% post contrast administration (p < 0.05, except for reader 1). Specificity improved from 48/48/54% on baseline US to 89/80/76% on CEUS (p < 0.05). Accuracy for specific lesion diagnosis was 62/59/50% pre and 90/77/72% post contrast (p < 0.05). Classification and characterisation post contrast were mildly inferior for off-site reading. Agreement between on-site and off-site readers of unenhanced scans was fair (κ = 0.29–0.39) while it was good for CEUS (κ = 0.63–0.79).

Conclusions

CEUS improves classification and characterisation of focal liver lesions and interobserver agreement compared to conventional US. Classification and characterisation post contrast were mildly but statistically significantly better for on-site than for off-site reading.     

Microbubble contrast agent with focused ultrasound to create brain lesions at low power levels: MR imaging and histologic study in rabbits

PURPOSE: To evaluate magnetic resonance (MR) imaging-based thermometry for predicting the onset and spatial extent of lesions produced by focused ultrasound combined with a microbubble contrast agent (Optison; GE Healthcare, Milwaukee, Wis) and to compare the resulting induced temperature increase and threshold for damage with those in studies performed without the agent. MATERIALS AND METHODS: The experiments were approved by the animal care committee. Fifty-three locations in the brains of 15 rabbits were sonicated with various exposure parameters by using a 1.5-MHz focused ultrasound transducer. MR imaging was used to map the temperature rise and, along with light microscopy, to examine the lesions. Diameters of isotherms created from thermometry were compared with the resulting lesions by using Bland-Altman analysis and linear regression. The minimum acoustic power necessary for lesion creation was determined, and the apparent temperature threshold for damage was calculated with probit analysis. These thresholds were compared with prior work performed without the contrast agent. The heating induced with the microbubbles was compared with that in sonications performed without them by using a t test. RESULTS: The MR imaging-mapped temperature distributions matched the shape of the lesions. The diameters of isotherms correlated well with diameters measured at contrast material-enhanced MR imaging (mean difference between measurements, 0.0 mm +/- 0.5; R = 0.93). The temperature increase with microbubbles was statistically larger (P < .01) than for sonications performed without microbubbles. In some locations (mostly continuous wave exposures), damage was observed along the ultrasound beam path. The time-averaged acoustic power damage threshold was reduced by 91% for 10-second exposures when compared with earlier studies performed without microbubbles. The probability of producing lesions was 50% at a temperature increase of 5.9 degrees C, 5.5 degrees C lower than was observed earlier without the agent. CONCLUSION: MR imaging-based temperature measurements appeared to correlate with focused ultrasound-induced lesions in the brain when microbubbles were present, even though the temperature appeared to be below the threshold for thermal damage.     

MnDPDP enhanced magnetic resonance imaging of focal liver lesions

Mangafodipir trisodium (MnDPDP) is a contrast agent for use in magnetic resonance imaging (MRI) of the liver. The agent is taken up by normal hepatocytes resulting in increased signal on T1-weighted imaging, and is excreted in the biliary system. Hepatocyte-containing liver neoplasms such as hepatomas or focal nodular hyperplasia (FNH), take up MnDPDP and demonstrate varying degrees of enhancement. Metastatic liver deposits and primary liver tumours of non-hepatocyte origin do not typically enhance with MnDPDP thus increasing their conspicuity compared with pre-contrast T1-weighted images. Metastases may demonstrate rim enhancement particularly on delayed imaging at 24 h, which can increase their conspicuity, thus allowing better visualization of small lesions. Functional biliary obstruction due to liver metastases can also result in wedge shaped areas of parenchymal enhancement.The MRI features of various focal liver after continuance with lesions following MnDPDP are discussed and illustrated including primary lesions such as hepatoma and secondary metastases.     

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.     

Real-time contrast-enhanced ultrasound imaging of focal liver lesions in fatty liver

PurposeThe objective of this study was to investigate the contrast-enhanced ultrasound (CEUS) imaging features of focal liver lesions (FLLs) in fatty liver.MethodOne hundred FLLs in 98 patients with fatty liver were evaluated with real-time CEUS.ResultsAll malignant FLLs showed hyperenhancement in arterial phase and contrast washout in portal and late phases. Among the FLLs, 3.3% of hemangiomas, 12.5% of focal nodular hyperplasias (FNHs), and 2.5% of focal fatty sparing lesions showed contrast washout in the late phase. The sensitivity and specificity for the characterization of hepatocellular carcinoma, metastasis, hemangioma, FNH, and focal fatty sparing lesions were 100% and 95.6%, 60% and 100%, 93.3% and 98.6%, 87.5% and 97.8%, and 92.6% and 100%, respectively.ConclusionsCorrect characterization of FLLs in fatty liver by CEUS is possible based on their typical enhancement patterns.     

Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

PURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were suspected of having focal liver lesions were included in a multicenter study and underwent dual-phase spiral CT and enhanced MR imaging. Image interpretations performed by independent experienced radiologists were compared with the final diagnosis that was based on all available clinical information (including histopathologic findings in 77 patients) and that was determined with consensus. Differences in classifications by using either enhanced MR imaging or dual-phase spiral CT were analyzed with the McNemar test, and receiver operating characteristic (ROC) curves were used to compare the diagnostic performance of enhanced MR imaging and dual-phase spiral CT. RESULTS: Lesion classification was correct in 108 (74%) patients with enhanced MR imaging and in 83 (57%) with dual-phase spiral CT (P =.001). Lesions were correctly classified as either malignant or benign in 123 (85%) patients with enhanced MR imaging and in 98 (68%) with dual-phase spiral CT (P =.001). Classification of lesions as either hepatocellular or nonhepatocellular was correct in 130 (90%) patients with enhanced MR imaging and in 93 (64%) with dual-phase spiral CT (P =.001). These differences remained when analyses were restricted to histopathologically confirmed diagnoses. Comparison of the ROC curves illustrated that enhanced MR imaging performance surpassed that of dual-phase spiral CT. CONCLUSION: Mn-DPDP-enhanced MR imaging is superior to dual-phase spiral CT in classification of focal liver lesions.     

64层螺旋CT肺动脉成像低管电压设置结合个体化对比剂应用的对照研究

Objective To investigate the feasibility of the low tube voltage setting and personalized contrast agent application in 64-row multi-slice spiral CT pulmonary angiography.Methods Ninety patients with high risk of pulmonary artery embolism were sequentially enrolled in the study and divided into 3 groups employing completely randomized design: (1) Regular group included 30 patients using 120 kV and fixed dose of 70 ml contrast agent, (2)Another 30 patients were in 120 kV group, using 120 kV and the contrast amount was determined according to the patient weight (1.0 ml/kg), (3) The remaining 30 patients were included in 100 kV group, using 100 kV and the contrast amount was also determined according to the patient weight(1.0 ml/kg).Administration of contrast agent was completed within 20 seconds for all the patients, followed by 20 ml of saline.The objective and subjective indexes for assessing CT image quality, CT dose index volume (CTDIvol) and effective received dose (ERD) were compared between 120 kV group and 100 kV group; then the contrast media volume, injection rate, objective CT image indexes and subjective indexes for image quality was compared between the 100 kV group and regular group.The variance analysis and post hoc test were employed for the statistical analysis.Results Compared with 120 kV group(3.4± 0.7), the image quality of 100 kV group(5.2±1.8)had higher noise(52.9%), but subjective index for the image quality demonstrated no differences(q=0.272 ,P=0.063)in mediastinum window while CTDIvol and ERD decreased for 34.9%[(9.5±0.0) vs (14.6±0.0) mGy]and 36.8%[(3.8±0.6) vs (2.4± 0.4) mSv].The mean CT values on pulmonary artery of 100 kV group[(269.2±54.7) HU]were 13.4% (31.8/237.4) higher than the 120 kV group[(237.4±62.9) HU], but there was no statistical differences eornpared to normal group(q=0.172,P=0.260).Conclusion Using low kV setting (100 kV) to reduce radiation dose is proved to be effective and feasible in 64-MSCT pulmonary angiography.Personalized contrast agent injection has clinical application value for specific patient group.