Characterization of Focal Liver Lesions with Contrast-Enhanced Ultrasound

The introduction of second generation microbubble ultrasound (US) contrast agents, such as SonoVue (Bracco, Milan, Italy), has considerably improved the diagnostic yield of US imaging for the evaluation of focal hepatic lesions in recent years because of its ability to very sensitively depict tumoral vascularity. In addition, contrast-enhanced US (CEUS) has the advantage of the absence of ionizing radiation, the widespread availability, even at the bedside, and the possibility to characterize a lesion as soon as detected on conventional B-mode US, commonly used as the first technique for exploration of the liver. The present review focuses on the basic principles of the technique and the various patterns of benign and malignant hepatic lesions at CEUS, contributing to their characterization. Understanding of these enhancement features at CEUS according to the type of tumors enables to make more accurate characterization of focal liver lesions as well as give better advice to oncologists, hepatologists or other clinicians in case of suspected liver tumors. (E-mail: fabio.piscaglia@unibo.it)     

Contrast-Enhanced Ultrasonography versus Contrast-Enhanced Magnetic Resonance Imaging in the Diagnosis of Mediastinal Tumors

The aim of the study was to evaluate and compare contrast-enhanced ultrasound (CEUS) and contrast-enhanced magnetic resonance imaging (CE-MRI) with respect to their value in the differential diagnosis between benign and malignant mediastinal tumors. Forty-two patients with mediastinal tumor underwent CEUS and CE-MRI respectively. The sensitivity, specificity, diagnostic coincidence rate, positive predictive value (PPV) and negative predictive value of the two methods were compared. The value of different enhancement patterns in the differential diagnosis of benign and malignant mediastinal tumors was analyzed. SonoLiver software was used to obtain the dynamic vascular pattern curve (DVPC) of the lesions, and parameters such as arrival time (AT), rise time (RT), time to peak (TTP), maximum intensity/peak intensity (IMAX) and quality of fit (QOF) were extracted from time–intensity curves for quantitative analysis. We found that (i) the specificity of CEUS was higher than that of CE-MRI, and the PPV and diagnostic coincidence rate of CEUS were equal to those of CE-MRI; (ii) the enhancement patterns and DVPC of CEUS differed between the benign and malignant groups, while there was no difference in CE-MRI enhancement intensity; and (iii) AT, RT and TTP in the malignant groups were significantly shorter, while IMAX was significantly higher. In conclusion, the application of quantitative parameters and DVPC of CEUS is worth popularizing. CEUS can be used as an effective alternative and complementary examination for patients who cannot undergo CE-MRI.     

磁共振扩散加权成像在肝脏占位病变中的应用

目的探讨磁共振（MR）扩散加权成像（DWI）在肝脏占位病变诊断和鉴别诊断中的应用价值。方法对40例常规磁共振成像（MRI）检查发现有肝脏占位病变患者,进行MRDWI,分析影像特点并测量表面扩散系数（ADC值）。结果40例肝脏占位病变DWI检出75处异常信号病灶。信号特征与病变结构、成分有关。但无一定特异性。病变的ADC值均值为：肝细胞癌（1．25±0．30）×10^-3mm^2／s,肝转移癌（1．12±0．52）×10^-3mm^2／s,肝血管瘤（2．27±0．49）×10^-3mm^2／s,肝囊肿（3．05±0．59）×10^-3mm^2／s,肝脓肿（1．91±0．46）×10^-3mm^2／s,各种病变间ADC值比较均有统计学意义（P〈0．05）。结论与常规MRI相比,DWI病变检出率不低于常规MRI,但各种病变间信号强度无明显特异性。ADC值测量对肝脏占位性病变的诊断和鉴别诊断。特别是对良恶性病变的鉴别有重要参考价值。     

超声造影在肝脏局灶性病变定性诊断中的应用研究

目的探讨不同性质之肝脏局灶性病变（FLLs）的超声造影（CEUS）特征表现。方法对60例肝脏局灶性病变患者进行超声造影检查,并与增强CT、病理结果进行对照。结果超声造影后各种FLLs显示不同的造影特点。CEUS定性诊断率与增强CT对照差别无统计学意义。结论CEUS能显示局灶性病变内微小血管的血流灌注情况,对FLLs的定性诊断具有重要的意义。     

超声造影在脾脏局灶性占位病变诊断中的价值

目的：探讨脾脏局灶性病变的超声造影特征及良恶性病变的差异。 方法：回顾性分析我院经手术或经皮穿刺活检病理确诊的24例脾脏局灶性病变患者的超声声像图特征,并比较良恶性病灶最大径、病灶数目、回声、边界、形态、动脉期及静脉期增强程度、动脉期增强病灶3min内有无明显廓清方面有无差异。 结果：共纳入24例患者的24个脾脏局灶性病变,包括15个良性病灶和9个恶性病灶。3个良性病灶超声造影表现为始终无增强,余 21个病灶均有增强,其中良性12个,恶性9个。动脉期增强病灶3min内有无明显廓清方面比较差异有统计学意义(P<0.05),良恶性病灶最大径、病灶数目、回声、边界、形态、动脉期及静脉期增强程度等指标比较差异均无统计学意义。 结论：脾脏局灶性病变具有一定超声造影特征,其中造影剂3min内是否有明显廓清对鉴别良恶性有借鉴意义。     

菲立磁增强MRI在肝脏局灶性病变诊断中的应用

评价菲立磁的安全性及在肝脏局灶性病变的检出及鉴别诊断中的作用。方法 30例B超或CT发现肝内局限性病灶的患者进行菲立磁增强（0.05ml/kg,静脉滴入）前后MRI扫描。结果 所有患者增强后天生命体征改变,也未出现严重不良反应。恶性病例16例,增强前发现病灶28个,增强后48个,多发现20个,均为转移处。89.6%的病灶增强后信号无降低,10.4%略降低。良性14例,多数良性病变（10／12,囊肿除外）信号可见不同程度减低。结论 菲立磁是一种安全、有效的肝脏阴性造影剂,对肝脏局灶性病变的良恶性鉴别有一定作用,能明显提高肝脏转移瘤的检出率。     

Contrast-Enhanced Ultrasound in the Characterization of Hepatocellular Carcinomas Treated by Ablation: Comparison with Contrast-Enhanced Magnetic Resonance Imaging

The purpose of this study was to evaluate the clinical utility of low-mechanical-index contrast-enhanced ultrasound (CEUS) in assessing the response to percutaneous microwave ablation in patients with hepatocellular carcinoma by comparing the results with those of contrast-enhanced magnetic resonance imaging (CEMRI). Between August 2005 and July 2011, 182 patients with 231 lesions treated by microwave ablation were included in the study. One month after microwave ablation, CEUS and CEMRI were performed to evaluate therapeutic responses. The difference in diagnostic accuracy between the two methods was analyzed to evaluate the value of contrast-enhanced ultrasound after microwave ablation. The final diagnosis was based on computed tomography and MRI typical findings of therapeutic response of hepatocellular carcinoma, proven serum tumor marker levels and additional follow-up. The sensitivity of CEUS and CEMRI in evaluating the therapeutic effect of hepatocellular carcinoma was 86.5% and 84.6%; the specificity, 98.3% and 98.9%; and the accuracy, 95.7% and 95.7%.There was no significant statistical disparity between CEUS and CEMRI (p > 0.05).The sensitivity, specificity and accuracy were 98.1, 97.2 and 97.8% when CEUS was used in combination with CEMRI to evaluate the therapeutic response of hepatocellular carcinoma to microwave ablation. CEUS examination was proven to be a tolerable and easy modality for assessment of the therapeutic effect of microwave ablation and can provide results comparable to those obtained with CEMRI. Combining the results of these two examinations may reduce false-positive and false-negative diagnoses.     

局灶性骨软骨损伤的磁共振成像表现

目的分析局灶性关节软骨损伤的MRI所见。方法按国际软骨修复协会（ICRS）分级法对68个病灶的MRI所见进行分析,着重观察关节软骨和软骨下骨的改变。结果58个分级为Ⅰ级2个,Ⅱ级5个,Ⅲ级14个,Ⅳ级37个;10个病灶属于剥脱性骨软骨炎Ⅰ级。MRI能发现关节镜无法观察到的软骨下骨病变。结论MRI对局灶性骨软骨损伤的显示准确。     

脂肪肝背景下肝局灶性病变的超声造影诊断

目的 评价超声造影对脂肪肝背景下肝局灶性病变的诊断价值.方法 对常规超声不能确诊的脂肪肝背景下的67个肝局灶性病变进行了超声造影检查,将超声造影检查结果同增强CT、增强MRI及病理诊断进行对比,分析超声造影检查的准确性、敏感性和特异性.结果 超声造影检查后,2例病灶仍不能确诊.3例炎性假瘤和1例肝细胞肝癌被误诊.超声造影检查的准确性为91.O%(61/67),敏感性和特异性分别为91.7%(11/12)和90.9%(50/55).结论 超声造影可大大提高脂肪肝背景下肝局灶性病变的诊断.     

超声造影参数成像对不典型表现的肝脏局灶性病变的诊断价值

目的 探讨超声造影(CEUS)动态血管模型参数成像(DVP)在不典型CEUS表现的肝脏局灶性病变(FLLs)诊断中的价值.方法 对262个FLLs行CEUS检查,据造影剂廓褪情况将FLLs分为典型表现组及不典型表现组.两组的CEUS录像资料分别运用Sonoliver 1.0软件进行分析.所有病例均经临床和病理证实.结果 主观判断与量化分析的结果 之间的一致性相比较,典型表现组较好(Kappa值=0.904),不典型表现组一般(Kappa值=0.403);主观判断与量化分析的定性诊断准确性相比较,典型表现组的2个准确性之间的差异没有统计学意义(P＞0.05),不典型表现组量化分析的诊断准确性要高于主观判断(P＜0.05).结论 结合运用CEUS参数成像软件进行分析,可以明显提高不典型病灶的定性诊断准确性.     

Prenatal Imaging of Fetal Lung Lesions: Magnetic Resonance Imaging Complements Ultrasound

Prenatal ultrasound has been used for 30 to 40 years in the evaluation of the fetus. In the 1980s, magnetic resonance imaging (MRI), given its high soft tissue detail, was introduced as an alternative method for fetal evaluation. Initially, MRI of pregnancy was limited to assessing maternal complications, as the fetal detail was poor because of motion on long acquisition times. However, in the 1990s, with the advent of short imaging sequences, fetal MRI rapidly established itself as a technique of diagnostic value. In this article, the authors present a case review of a fetus with a lung lesion, demonstrating the value of this modality.     

Automatic Identification of the Optimal Reference Frame for Segmentation and Quantification of Focal Liver Lesions in Contrast-Enhanced Ultrasound

Post-examination interpretation of contrast-enhanced ultrasound (CEUS) cineloops of focal liver lesions (FLLs) requires offline manual assessment by experienced radiologists, which is time-consuming and generates subjective results. Such assessment usually starts by manually identifying a reference frame, where FLL and healthy parenchyma are well-distinguished. This study proposes an automatic computational method to objectively identify the optimal reference frame for distinguishing and hence delineating an FLL, by statistically analyzing the temporal intensity variation across the spatially discretized ultrasonographic image. Level of confidence and clinical value of the proposed method were quantitatively evaluated on retrospective multi-institutional data (n = 64) and compared with expert interpretations. Results support the proposed method for facilitating easier, quicker and reproducible assessment of FLLs, further increasing the radiologists' confidence in diagnostic decisions. Finally, our method yields a useful training tool for radiologists, widening CEUS use in non-specialist centers, potentially leading to reduced turnaround times and lower patient anxiety and healthcare costs.     

Revised Value of Contrast-Enhanced Ultrasound for Solid Hypo-Echoic Thyroid Nodules Graded with the Thyroid Imaging Reporting and Data System

The use of ultrasound in differentiation of benign and malignant solid hypo-echoic thyroid nodules is a dilemma in clinical practice. The aim of this study was to investigate the revised value of contrast-enhanced ultrasound (CEUS) for differentiating solid hypo-echoic thyroid nodules using the Thyroid Imaging Reporting and Data System (TI-RADS).The study included 135 patients with 135 nodules confirmed by fine-needle aspiration and/or surgery. Every nodule underwent both conventional US and CEUS. Binary logistic regression analysis for conventional US features revealed that irregular shape, microcalcification and height greater than width were significant malignant predictive features. Binary logistic analysis for CEUS features indicated that hetero-enhancement, slow wash-in, an ill-defined enhancement border and fast wash-out were significantly associated with malignancy. The areas under the curve of the TI-RADS, CEUS and the combination were 0.806, 0.934 and 0.950, respectively. CEUS is a potentially useful tool in the differentiation of solid hypo-echoic thyroid nodules.     

A Comprehensive Motion Compensation Method for In-Plane and Out-of-Plane Motion in Dynamic Contrast-Enhanced Ultrasound of Focal Liver Lesions

Contrast-enhanced ultrasound (CEUS) acquisitions of focal liver lesions are affected by motion, which has an impact on contrast signal quantification. We therefore developed and tested, in a large patient cohort, a motion compensation algorithm called the Iterative Local Search Algorithm (ILSA), which can correct for both periodic and non-periodic in-plane motion and can reject frames with out-of-plane motion. CEUS cines of 183 focal liver lesions in 155 patients from three hospitals were used to develop and test ILSA. Performance was evaluated through quantitative metrics, including the root mean square error and R² in fitting time–intensity curves and standard deviation value of B-mode intensities, computed across cine frames), and qualitative evaluation, including B-mode mean intensity projection images and parametric perfusion imaging. The median root mean square error significantly decreased from 0.032 to 0.024 (p < 0.001). Median R² significantly increased from 0.88 to 0.93 (p < 0.001). The median standard deviation value of B-mode intensities significantly decreased from 6.2 to 5.0 (p < 0.001). B-Mode mean intensity projection images revealed improved spatial resolution. Parametric perfusion imaging also exhibited improved spatial detail and better differentiation between lesion and background liver parenchyma. ILSA can compensate for all types of motion encountered during liver CEUS, potentially improving contrast signal quantification of focal liver lesions.     

Advances in Contrast Agents for Contrast-Enhanced Magnetic Resonance Imaging

IntroductionMagnetic resonance imaging (MRI) is a well-established medical invention in modern medical technology diagnosis. It is a nondestructive, versatile, and sensitive technique with a high spatial resolution for medical diagnosis. However, MRI has some limitations in differentiating certain tissues, particularly tiny blood vessels, pathological to healthy tissues, specific tumors, and inflammatory conditions such as arthritis, atherosclerosis, and multiple sclerosis. The contrast agent (CA) assisted imaging is the best possible solution to resolve the limitations of MRI.MethodThe literature review was carried out using the keywords, “MRI, T1&T2 relaxation, MRI CAs, delivery and adverse effects, classification of CAs.” The tools used for the literature search were PubMed, Scopus, and Google Scholar.Result and DiscussionThe literature findings focus on MRI technique, limitations, and possible solutions. Primarily, the review focuses on the mechanism of CAs in image formation with detailed explanations of T1 and T2 relaxations, the mechanism of the MRI-CA image formations. This review presents the adverse effects of CA as well as available marketed formulations and recent patents to extent complete information about the MRI-CA.ConclusionMRI generates detailed visual information of various tissues with high resolution and contrast. The proton present in the biological fluid plays a crucial role in MR image formation, and it is unable to distinguish pathological conditions in many cases. The CAs are the best solution to resolve the limitation by interacting with native protons. The present review discusses the mechanism of CAs in contrast enhancement and its broad classification with the latest literature. Furthermore, the article presents information about CA biodistribution and adverse effects. The review concludes with an appropriate solution for adverse effects and presents the future prospective for researchers to develop advanced formulations.