EFSUMB statement on medical student education in ultrasound [short version].

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) recommends that ultrasound should be used systematically as an easy accessible and instructive educational tool in the curriculum of modern medical schools. Medical students should acquire theoretical knowledge of the modality and hands-on training should be implemented and adhere to evidence-based principles. In this paper we summarise EFSUMB policy statements on medical student education in ultrasound.

Parotid Gland Lesions: Multiparametric Ultrasound and MRI Features.

High-resolution ultrasound (US), as a readily available, cost-effective and harmless imaging technique, is appropriately the initial imaging modality for salivary gland lesions. Benign tumors are reported to present with regular and well-defined margins, a homogeneous hypoechoic structure and demarcated vessel distribution, whereas malignant lesions are irregular, heterogeneous and diffusely perfused. Ultrasound and color Doppler features of benign and malignant salivary gland lesions overlap, and many benign tumors, particularly pleomorphic adenomas, may appear irregularly shaped, with a heterogeneous echo-structure indistinguishable from a malignant lesion. Often skilled US operators are not always able to differentiate benign from malignant lesions. The introduction of US contrast agents has allowed further perspectives in the possible improvement of lesion characterization, and the emergence of US elastography, an innovative tool for assessing lesion stiffness/elasticity characteristics, has been advocated for differentiating salivary gland lesions. When lesions are atypical on US, contrast-enhanced magnetic resonance (MR) imaging is usually the definitive imaging modality. We present a current review of benign and malignant parotid gland tumors with emphasis on the role of multiparametric US and MR imaging.

Inter-observer agreement for the evaluation of bone involvement on Whole Body Low Dose Computed Tomography (WBLDCT) in Multiple Myeloma (MM).

OBJECTIVE: We aimed to assess inter-observer agreement in bone involvement evaluation and define accuracy and reproducibility of MDCT images analysis in Multiple Myeloma (MM), by comparing two acquisition protocols at two different institutions. METHODS: A total of 100 MM patients underwent whole body low-dose computed tomography (WB-LDCT), with two protocols: Group I (50 patients), 80 kV and 200-230 mAs; Group II, 120 kV-40 mAs. Four readers (two experts) retrospectively reviewed 22 anatomical districts, reporting the following for each patient: 1) osteolytic lesions; 2) cortical bone integrity; 3) fractures; 4) risk of vertebral collapse; 5) hyperattenuating bone lesions; and 6) extraosseous extension. Inter-observer agreement (by all readers, expert and young observers and comparison of the two protocols) was then statistically analyzed. RESULTS: According to Cohen's criteria, inter-observer agreement among the four readers and between experts and residents was good for the detection of bone lesions and extra-medullary extension, and for the evaluation of risk of collapse and cortical integrity. There was good agreement when comparing the two protocols. A greater variability was found for the evaluation of hyperattenuating lesions and the presence of fractures. CONCLUSIONS: WB-LDCT represents a reproducible and reliable technique that is helpful for defining bone disease in MM patients, with partial influence of readers' experience. KEY POINTS: • MDCT represents a reproducible technique for defining bone disease in MM. • Overall inter-observer agreement is good, even when comparing two different protocols. • Influence of readers' experience on image analysis is partial.

EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 1: Basic principles and technology.

The technical part of these Guidelines and Recommendations, produced under the auspices of EFSUMB, provides an introduction to the physical principles and technology on which all forms of current commercially available ultrasound elastography are based. A difference in shear modulus is the common underlying physical mechanism that provides tissue contrast in all elastograms. The relationship between the alternative technologies is considered in terms of the method used to take advantage of this. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided on optimisation of scanning technique, image display, image interpretation and some of the known image artefacts.

EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 2: Clinical applications.

The clinical part of these Guidelines and Recommendations produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology EFSUMB assesses the clinically used applications of all forms of elastography, stressing the evidence from meta-analyses and giving practical advice for their uses and interpretation. Diffuse liver disease forms the largest section, reflecting the wide experience with transient and shear wave elastography . Then follow the breast, thyroid, gastro-intestinal tract, endoscopic elastography, the prostate and the musculo-skeletal system using strain and shear wave elastography as appropriate. The document is intended to form a reference and to guide clinical users in a practical way.

Presurgical setting of secondary hyperparathyroidism using high-resolution sonography and color Doppler.

PURPOSE: High-resolution sonography (US) with color Doppler imaging (CDI) is a simple, noninvasive, safe and repeatable technique able to highlight the presence of hyperplastic parathyroid glands and changes in their volume, structure, and vascularization during uremia. The primary aim of this study was to assess the diagnostic accuracy of US and the sensitivity for localizing parathyroid glands with a volume ≥ 500 mm(3). The secondary aim was to assess the parameters that define parathyroid glandular perfusion. MATERIALS AND METHODS: The diagnostic use of US was assessed in 40 consecutive uremic patients with severe secondary hyperparathyroidism (sHPT) who were receiving maintenance hemodialysis or conservative therapy with a hypoproteic-hypophosphoric diet and had undergone parathyroidectomy. Prior to surgery (99m)TC-sestamibi scintigraphy (SM) was performed in all patients. RESULTS: The sensitivity, specificity, positive predictive value and accuracy of US were 74 %, 75 %, 98 %, and 74 %, respectively. The sensitivity for localizing glands with a volume ≥ 500 mm(3) was 90 %. US and SM had a combined sensitivity of 83 %. The vascularization of parathyroid glands became more evident with increasing glandular volume. With CDI, the signs of hypervascularization (i. e. an enlarged feeding artery at the hilum, a peripheral arc of vascularity and/or ray-like endonodular vessels) were present in 77 % of glands with a volume ≥ 500 mm(3). CONCLUSION: The sensitivity of US is higher than that of SM, but it cannot be compared with that of parathyroidectomy (74 vs. 95 %). However, US/CDI is able to characterize glands with different volumes and vascular patterns. Since glandular volume and vascularization are indicative of the severity of sHPT, this study suggests that the main role of US/CDI in the setting of sHPT should be to complete the diagnosis and to evaluate the morphological changes of enlarged glands during uremia in order to define surgical timing, rather than to assess the presurgical location of glands.

Detection of hepatic metastases from colorectal cancer: prospective evaluation of gray scale US versus SonoVue® low mechanical index real time-enhanced US as compared with multidetector-CT or Gd-BOPTA-MRI.

PURPOSE: To compare ultrasound (US), low-mechanical index contrast enhanced US (CEUS) and multidetector-CT (MDCT) for the detection of hepatic metastases from colorectal cancer. METHODS AND MATERIALS: From January to June 2006, 110 patients (65 males, 45 females; mean age 62 years; range 39-78) with suspected hepatic lesions from colorectal cancer were prospectively evaluated with US, CEUS and MDCT by two independent readers. Intraoperative ultrasonography (IOUS, n = 45) or a follow-up up for at least 6 months by using MDCT or Gd-BOPTA-enhanced MRI was considered the gold standard. McNemar test was employed. RESULTS: Reference standards revealed 430 metastases in 110 patients. On a patient-by-patients analysis, CEUS improved US sensitivity from 67.4-71.6% to 93.4-95.8% (p < 0.05). On a lesion-by-lesion analysis, CEUS improved the sensitivity of US from 60.9-64.9% to 85.3-92.8% (p < 0.001). The specificity increased from 50-60% to 76.7-83.3%. No significant differences in sensitivity or specificity between CEUS and MDCT were found. Contrast-enhanced US was significantly more sensitive than baseline US in the detection of metastases smaller than 1 cm (p < 0.001) with an increase in sensitivity from 29.1-35% to 63.3-76.6% no significant statistical difference was identified when compared with MDCT (sensitivity of 73.3-75.8%). CONCLUSIONS: CEUS is significantly more accurate than US and highly comparable with MDCT in the detection of liver metastases from colorectal cancer. Therefore, in the evaluation of patients with suspected hepatic metastases from colorectal tumour, US examination must be performed after contrast administration.

Is contrast-enhanced US alternative to spiral CT in the assessment of treatment outcome of radiofrequency ablation in hepatocellular carcinoma?

PURPOSE: The present study was conducted to assess the efficacy of contrast-enhanced ultrasound with low mechanical index in evaluating the response of percutaneous radiofrequency ablation treatment of hepatocellular carcinoma by comparing it with 4-row spiral computed tomography. MATERIALS AND METHODS: 100 consecutive patients (65 men and 35 women; age range: 62 - 76 years) with solitary hepatocellular carcinomas (mean lesion diameter: 3.7 cm +/- 1.1 cm SD) underwent internally cooled radiofrequency ablation. Therapeutic response was evaluated at one month after the treatment with triple-phasic contrast-enhanced spiral CT and low-mechanical index contrast-enhanced ultrasound following bolus injection of 2.4 ml of Sonovue (Bracco, Milan). 60 out of 100 patients were followed up for another 3 months. Contrast-enhanced sonographic studies were reviewed by two blinded radiologists in consensus. Sensitivity, specificity, NPV and PPV of contrast-enhanced ultrasound examination were determined. RESULTS: After treatment, contrast-enhanced ultrasound identified persistent signal enhancement in 24 patients (24 %), whereas no intratumoral enhancement was detected in the remaining 76 patients (76 %). Using CT imaging as gold standard, the sensitivity, specificity, NPV, and PPV of contrast enhanced ultrasound were 92.3 % (95 % CI = 75.9 - 97.9 %), 100 % (95 % CI = 95.2 - 100 %), 97.4 % (95 % CI = 91.1 - 99.3 %), and 100 % (95 % CI = 86.2 - 100 %). CONCLUSION: Contrast-enhanced ultrasound with low mechanical index using Sonovue is a feasible tool in evaluating the response of hepatocellular carcinoma to radiofrequency ablation. Accuracy is comparable to 4-row spiral CT.

MR Micro-Neurography and a Segmentation Protocol Applied to Diabetic Neuropathy.

The aim of this study was to assess with MRI morphometric ultrastructural changes in nerves affected by diabetic peripheral neuropathy (DPN). We used an MR micro-neurography imaging protocol and a semiautomated technique of tissue segmentation to visualize and measure the volume of internal nerve components, such as the epineurium and nerve fascicles. The tibial nerves of 16 patients affected by DPN and of 15 healthy volunteers were imaged. Nerves volume (NV), fascicles volume (FV), fascicles to nerve ratio (FNR), and nerves cross-sectional areas (CSA) were obtained. In patients with DPN the NV was increased and the FNR was decreased, as a result of an increase of the epineurium (FNR in diabetic neuropathy 0,665; in controls 0,699, p = 0,040). CSA was increased in subjects with DPN (12,84 mm2 versus 10,22 mm2, p = 0,003). The FV was increased in patients with moderate to severe DPN. We have demonstrated structural changes occurring in nerves affected by DPN, which otherwise are assessable only with an invasive biopsy. MR micro-neurography appears to be suitable for the study of microscopic changes in tibial nerves of diabetic patients.

What is the role of contrast-enhanced ultrasound in the evaluation of the endoleak of aortic endoprostheses? A comparison between CEUS and CT on a widespread scale.

OBJECTIVE: To evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in comparison to CT angiography (CTA) to identify and classify endoleaks following abdominal aortic aneurism repair with endoprosthesis. MATERIALS AND METHODS: A retrospective analysis of 181 patients treated with EVAR, from September 2009 to September 2014, was performed. Patients were evaluated with CEUS, CTA and angiography in the cases requiring treatment. Sac diameter, sac integrity, identification and classification of endoleaks were taken into consideration. Sensitivity, specificity, accuracy and negative predictive values were considered for each modality of endoleak identification. RESULTS: Forty-two endoleaks (23.2%; type II: 39 cases, type III: 3 cases) were documented. Sensitivity and specificity of CEUS and CT were, respectively, 97.6 and 90.5, 100 and 100%. In two cases, CEUS was able to better classify endoleaks compared to CT. CONCLUSIONS: CEUS accuracy to identify endoleaks following EVAR is similar to CT. CEUS should be considered as an effective modality for the long-term surveillance of EVAR because of its capability to correctly classify endoleaks with no ionizing radiation exposure.

EFSUMB Statement on Medical Student Education in Ultrasound [long version].

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) recommends that ultrasound should be used systematically as an easy accessible and instructive educational tool in the curriculum of modern medical schools. Medical students should acquire theoretical knowledge of the modality and hands-on training should be implemented and adhere to evidence-based principles. In this paper we report EFSUMB policy statements on medical student education in ultrasound that in a short version is already published in Ultraschall in der Medizin 1.

Breast hamartoma: ultrasound, elastosonographic, and mammographic features. Mini pictorial essay.

Hamartomas, also known as fibroadenolipomas, are rare, benign formations that can develop in various organs, including the breast. They present clinically as a soft, mobile nodular lesions and are generally asymptomatic. They may be discovered incidentally during imaging studies performed for other reasons. Owing to the increasingly widespread use of mammographic screening, the diagnosis of breast hamartomas is on the rise. The masses are associated with specific mammographic and sonographic features that reflect their diverse tissue components. They also appear to present reproducible features on elastography. This article reviews the typical features of breast hamartomas seen on these three imaging modalities.

Growing indications for CEUS: The kidney, testis, lymph nodes, thyroid, prostate, and small bowel.

Contrast enhanced ultrasonography (CEUS) is increasingly used for non-hepatic applications as well, so that nearly all organs have been investigated. Among them, there is a growing clinical use for a variety of pathologies of the kidney, testis, and small bowel. The possibility to differentiate benign from malignant nodes in cancer patients has been investigated. A new application is in the detection of sentinel nodes after intradermal microbubble injection. The need to distinguish thyroid nodules eligible for fine needle aspiration cytology has led to the use of CEUS in thyroid examinations as well. The potential of CEUS for prostate cancer detection has been extensively investigated, with encouraging initial results. Early promise, however, has not been fulfilled. New perspective regards evaluation of the extent of prostate tissue devascularization following ablative treatments.

The latest in ultrasound: three-dimensional imaging. Part II.

INTRODUCTION: The three-dimensional (3D) reconstruction of ultrasound images has become a widespread option in ultrasound equipment. Specific softwares have become available and 3D reconstruction feasible since the early 1990s, particularly since 1994. POSSIBLE CLINICAL APPLICATIONS: Several clinical applications are feasible in all parenchymatous organs (mainly the liver and prostate), hollow viscera (e.g. the bladder and gallbladder), peripheral vessels (supra-aortic trunks and limb vessels) and central (the aorta and iliac arteries) or cerebral vessels. Moreover, tumoral vessels in parenchymatous organs can be reconstructed, and even the fetus in the uterine cavity, with excellent detailing. The recent introduction of echocontrast agents and second harmonic imaging has permitted to study normal and abnormal peripheral, central and parenchymatous vessels, with similar patterns to those obtained with digital angiography. The spatial relationships between the vascular structures of the liver, kidney and placenta were studied with 3D ultrasound angiograms. The applications of this new technique include the analysis of vascular anatomy and the potential assessment of organ perfusion. THE LATEST APPLICATIONS--INTRAVASCULAR STUDIES: Some catheters with an ultrasound transducer in the tip have been tested for intravascular studies. Just like conventional transducers, they provide two-dimensional (2D) images which are then postprocessed into longitudinal 3D or volume reconstructions. The former resemble angiographic images and can be viewed 3D rotating the image along its longitudinal axis. Volume images, which are more complex and slower to obtain, can be rotated on any spatial plane and provide rich detailing of the internal vascular lumen. The clinical importance of intravascular ultrasound with 3D volume reconstructions lies in the diagnosis of vascular conditions and the assessment and monitoring of intravascular interventional procedures--e.g. to detect inaccurate deployment of intravascular stents and endoluminal grafts during the maneuver. Three-dimensional reconstructions involve geometric data assembly and volumetric interpolation of a spatially related sequence of tomographic cross sections generated by an ultrasound catheter withdrawn at a constant rate through a vascular segment of interest, resulting in the display of a straight segment. Therefore particular care is needed and there are some useful hints to avoid mistakes. CONCLUSIONS: Three dimensional reconstructions of B-mode and color Doppler images are no longer a work in progress and their clinical importance and possible applications are both established and ever-increasing. On the other hand, independent of the different types of energy used, also computed tomography and magnetic resonance 3D reconstructions are very useful from a clinical viewpoint and they have become an established routine technique for both these methods. It is very likely that 3D volume reconstructions in ultrasound will find numerous applications in the near future. They may help to increase the diagnostic confidence and to facilitate diagnosis, intraprocedure monitoring in interventional radiology and follow-up and also to reduce the number of invasive examinations with iodinated contrast agents. This could result in cutting the cost and duration of the most expensive examinations. New, although invasive, applications can be hypothesized for intravascular or intraluminal catheters with an ultrasound transducer inside.

Ultrasound contrast agents: basic principles.

INTRODUCTION: Ultrasonography lacked substances to be administered to patients to improve or increase the diagnostic yield, which is peculiar considering that contrast agents have long been used with all the other imaging techniques. Fortunately some contrast agents, most of them consisting in gas microbubbles, have been recently introduced for ultrasound imaging too: this review will focus on their history, behavior, current applications and future developments. Echocontrast agent research is in progress and many new agents are expected to be marketed this and next year, to be added to Levovist by Schering AG (Berlin, Germany), to enhance the ultrasound signal safely and effectively. No definitive conclusions can be drawn yet on the actual merits of each contrast agent, but all of them seem to be both effective and safe, meaning that their future success will depend on the relative cost-effectiveness and peculiarities. THE BASIC PRINCIPLES OF ECHOCONTRAST AGENTS: The microbubbles act as echo-enhancers by basically the same mechanism as that determining echo-scattering in all the other cases of diagnostic ultrasound, namely that the backscattering echo intensity is proportional to the change in acoustic impedance between the blood and the gas making the bubbles. The different acoustic impedance at this interface is very high and in fact all of the incident sound is reflected, even though not all of it will of course go back to the transducer. But the acoustic wave reflection, though nearly complete, would not be sufficient to determine a strong US enhancement because the microbubbles are very small and are sparse in the circulation. Moreover, reflectivity is proportional to the fourth power of a particle diameter but also directly proportional to the concentration of the particles themselves. SECOND HARMONIC IMAGING: As we said above, the microbubbles reached by an ultrasound signal resonate with a specific frequency depending on microbubble diameter. However, the main resonance frequency is not the only resonance frequency of the bubble itself and multiple frequencies of the fundamental one are emitted, just like in a musical instrument. These harmonic frequencies have decreasing intensity, but the second frequency, known as the second harmonic, is still strong enough to be used for diagnostic purposes. The theoretical advantage of the harmonic over the fundamental frequency is that only contrast agent microbubbles resonate with harmonic frequencies, while adjacent tissues do not resonate, or else their harmonic resonation is very little. Thus, using a unit especially set to produce ultrasounds at a given frequency (3.5 MHz) and receive an ultrasound signal twice as powerful (7 MHz) it will be possible to show the contrast agent only, without any artifact from the surrounding anatomical structures, with a markedly improved signal-to-noise ratio. A similar effect to digital subtraction in angiography can thus be obtained, even though through a totally different process. Moreover, second harmonic imaging permits to show extremely small vessels (down to 40 microm) with very slow flow, which would be missed with a conventional method. B-mode imaging can also depict the microbubbles in the myocardium suppressing nearly all the artifacts from cardiac muscle motion. Recently a peculiar behavior of microbubbles has been observed which may permit contrast agent detection even in capillaries. This method is variously known as sonoscintigraphy, loss of correlation, stimulated acoustic emission and transient scattering. The contrast agent microbubbles reached by an ultrasound beam powerful enough explode producing a strong and very short backscatter echo which is read by the unit as a Doppler signal and results in a color pixel where the individual microbubble exploded. CONCLUSIONS: The microbubble contrast agents developed and introduced as safe and effective echo-enhancers in present-day clinical practice will open up new oppurtunities

New prospects for ultrasound contrast agents.

Considering the several suggestions regarding the future developments of echocontrast agents, there is a striking difference between the few compounds actually available on the market and used in clinical practice and those undergoing experimental clinical trials. It is therefore difficult to predict what will be the actual impact of these agents in the next future. Future developments will probably go beyond color enhancement which was the end-point till a very short time ago. They can be schematically summarized as follows: (1) development of new substances which enhance both color and gray scales; (2) use of new-generation substances, such as BR1 (Bracco, Milan, Italy) and EchoGen (Sonus, Bothell, WA), which use a gas other than air, such as perfluorate compounds which are more stable and guarantee longer and stronger effects; (3) use of more complex compounds acting at different levels. For example, SHU 536A (Sonovist) produces resonance phenomena with the second and third harmonics, and also stimulated acoustic emission which permits the morphological study of liver parenchyma. Other promising compounds are liposomes and aerosomes. Among the new possibilities in recording and observing phenomena, we can distinguish two main application fields: one is based on the physics of ultrasound and related to the presence of microbubbles in an acoustic field. These phenomena are generally obtained increasing the emission acoustic pressure, which eventually results in microbubble destruction and they are called nonlinear because there is no direct relationship between emission and return frequencies. These phenomena, which are detectable only with dedicated equipment, include: the resonance phenomenon with harmonic emission; intermittent harmonic emission and stimulated acoustic emission. The other application field is not strictly related to ultrasound physics and includes all the systems which can detect the presence of microbubles qualitatively or quantitatively. Other possible applications are related to the possibility of acquiring not only morphological but also functional data, especially in cardiology and neurology. Finally, targeted agents are potentially capable of demonstrating receptor sites or specific molecules, which may open very interesting therapeutic routes.

Contrast enhancing agents in ultrasonography: clinical applications.

INTRODUCTION: As ultrasound remains a poorly sensitive method, echocontrast agents make a real difference. At least 29 echocontrast agents are currently on trial worldwide; their chemical composition, mechanisms of action and possible clinical applications are different. The state of the art of echocontrast agents is discussed: their established applications, those expected in the near future and finally their hypothetical, ideal applications. POTENTIAL CLINICAL APPLICATIONS: An extravascular and a vascular domain can be considered. The former includes the gastrointestinal tract and body cavities--both the normal (bladder, uterus, tubes and so on) and the abnormal (abscesses, fistulas, pericardium, peritoneum and so on) ones. Echocontrast agents can: (1) create or improve an acoustic window; (2) distend some organs and fill them with a liquid, with homogenous attenuation of the ultrasound beam; (3) displace the air-containing intestinal loops; (4) depict the walls, the shape and the contours of a normal or abnormal cavity; (5) detect abnormal communications, fistulas and drainages; and (6) evaluate the amount of fluid in the pleural, pericardial or peritoneal cavities. As for vascular applications, this domain sees the highest number of echocontrast agents on trial or on the market. The best know of them are: Levovist (Schering AG, Berlin, Germany), BR1 (Bracco, Milan, Italy) and EchoGen (Abbott, USA). All these act by enhancing arteries, veins and capillaries. The clinical applications validated in clinical trials mainly regard studies in intracranial and neck vessels and the vascularity of upper and especially lower limbs of renal vessels. Tumor macrovascularity (and in the future, hopefully microvascularity) can also be studied in parenchymatous and/or glandular organs, as well as in intra- and extra-abdominal parenchymatous organs in the periskeletal soft tissues. Clinical validation has also been obtained in the follow-up of tumors submitted to ablation therapy (chemoembolization, ethanol injection, thermal ablation) and in echocardiography, both for morphological studies in the cardiac cavities and for the cardiac wall perfusion. CONCLUSIONS: In a subgroup of 513 out of 1275 patients examined Europe-wide, the contrast agent Levovist increased the diagnostic confidence from 27.4 +/- 22.5 to 77.2 +/- 22.5%. Such data encourage further trials to validate current preliminary results.

[Clinico-statistical review of 74 cases of subcutaneous rupture of the Achilles tendon]. / Revisione clinico-statistica di 74 casi di rottura sottocutanea del tendine di Achille.

The Authors report 74 cases of subcutaneous hole of Achille's tendon that were treated surgically. 52 patients were clinically controlled at a distance from 1 to 5 years. The functional result at a distance is good in 67,3% of cases, satisfactory in 25%, insufficient in 4%. They point out an hig incidence of local post-operating complications (29,8%), especially when the paratendinea medial incision has been made. The authors suggest to opt for a paratendinea lateral incision and, experimentally, to drop the use of hemostatic string.

Topical role and future perspectives of sonographic contrast agents in the differential diagnosis of solid thyroid lesions.

Gray scale sonography and US-guided biopsy are cost-effective and reliable procedures in the differential diagnosis of focal thyroid lesions. The frequent presence of multiple foci can make multiple biopsies intolerable to the patient. The use of a sonographic contrast agent (Levovist) composed of microbubbles was evaluated in the differential diagnosis of focal solid lesions of the thyroid. Time/intensity curves after bolus injection of contrast were studied with samplings at the level of focal lesions, extranodular parenchyma and common carotid in 29 lesions of 25 patients (16 females and 9 males) ranging in age 21 to 68 years. The evaluated parameters were: the curve morphology, the time to peak value, the mean enhancement time and the wash-in/out variate gamma curve. All focal lesions underwent biopsy. No significant differences were observed as for mean enhancement time while for time to peak values only two malignant lesions seemed to show values different from those of other solid lesions. Wash-in/out variate gamma curves seemed more interesting; they presented a dual morphology: 1) parenchymal for hyperplastic areas, pseudonodular neoformations during thyroiditis and healthy thyroid parenchyma, 2) vascular for malignant lesions and carotid lumen. Autonomous nodules showed an intermediate morphology. In spite of major limitations, the results seem to pave the way for additional possibilities of noninvasive differential diagnosis in the evaluation of focal solid thyroid lesions.