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Intestinal US has to be performed very accurately, to obtain an exploration of both small bowel and cholical loops that will be the most complete that is possible; so, this technique requires adequately trained operators. Convex and linear probes with frequency between 3.5 and 7.5 MHz are used: the first ones for the panoramic evaluation and to study the middle-distal sigma and rectum; the second ones to perform a detailed examination of the bowel wall. US allows to evaluate not only the thickness and structure of the bowel wall, but also the content and peristalsis of the loops, their compressibility and movability, the perivisceral spaces and the abdominal organs. In Crohn's disease, US, completed everytime by the color-power-Doppler, shows wall thickening until 20 mm and above, with multi-stratified structure that could be regular, or more and more altered until the hypoechogenic view; the bowel vascularisation could be absent or less or more increased, due to the stadium of the disease itself. Furthermore, US allows to demonstrate the presence of stenosis and various other complications (abscesses inside or outside the walls, fistulas, involvement of other organs, free fluid collections); the use of II generation US contrast media could afford information about the activity of the disease. US has a very important role in the follow-up of patients with diagnosis of Crohn's disease, to monitor the response to the medical therapy and to discover complications; US must be performed as first in subjects with abdominal pain and diarrhea, to select the ones that need more invasive examinations.

Objective: To prospectively evaluate the vascularization of the thickened terminal ileum in Crohn's disease patients using contrast enhanced ultrasound (CEUS) and to compare the clinical activity measured by the Crohn's disease activity index (CDAI) with the CEUS findings., Patients and Methods: Forty-eight of 104 consecutive patients (17 females and 31 males, aged 42.4+/-13.8 years) with a thickened terminal ileum at sonography were recruited for the study. CEUS examinations were performed using a real-time low mechanical index harmonic ultrasound technique after intravenous injection of a second generation contrast agent. We used two parameters to assess the vascularization of the bowel wall: a semi-quantitative method, the pattern of enhancement (which is the description of the arrangement of the enhanced layer in the bowel wall) and a quantitative method, the E/W ratio (which is the ratio between the major thickness of the enhanced layer, E, and the thickness of the entire wall section, W). In order to assess the accuracy of the CEUS findings in discriminating between active and inactive patients according to CDAI values (>150 and < or =150, respectively), the patterns of enhancement (four patterns) were dichotomized in two groups and an E/W ratio cutoff value was calculated to differentiate between poor and abundant bowel wall enhancement., Results: The CEUS findings, namely the pattern of enhancement and the E/W ratio (best cutoff value ranging between 0.43 and 0.47), had a sensitivity of 81.0% and 81.0%, respectively, a specificity of 63.0% and 55.6%, respectively, a positive predictive value of 63.0% and 58.6%, respectively, and a negative predictive value of 81.0% and 78.9%, respectively, in distinguishing patients with active and inactive disease., Conclusions: CEUS assessment of diseased bowel wall vascularization may be a sensitive tool for the detection of inflammatory activity.

Objective: The diagnosis of most skin diseases, both focal and diffuse, has long relied mainly on physical examination findings. The recent introduction of technologically advanced ultrasound equipment using 20 MHz probes has permitted the specific application of ultrasound to dermatology. Accordingly, we investigated whether the findings at very high frequencies can represent a valid adjunct to clinical assessment in many skin conditions, including neoplasms, inflammatory states and diseases of unknown origin., Materials and Methods: Skin lesions are studied using high frequency probes, which very clearly detail the three layers (epidermis, dermis and subcutaneous tissues) forming the normal skin. The choice of the probes frequency should depend mainly on the lesion diameters and site. Electronic 7.5-13 MHz linear probes depict flat and regular surfaces effectively and provide a wider field of surface vision and, therefore, a wider view than sectorial probes. Water bath sectorial mechanical probes with 10-20 MHz frequency have very superficial focusing and are excellent to study irregular surfaces., Results: High frequency ultrasound can be usefully correlated with clinical tests to study focal skin lesions. The diagnosis of most benign skin cancers is usually made on clinical bases. Ultrasound examinations are performed preoperatively in questionable cases. Malignant neoplasms appear at ultrasound as hypoechoic focal lesions, generally with no specific features in relation to the histologic type; nevertheless, preoperative ultrasound may play an important role in that it measures the thickness of cutaneous melanoma, which is a very important prognostic factor. In particular, 20 MHz probes permit to assess the depth of melanoma invasion. The sonographic evaluation of melanoma thickness is usually in agreement with histologic findings. 'Satellite' neoplastic lesions growing near the main tumor can also be revealed. Color and power Doppler studies may be combined with gray-scale imaging: the identification of abnormal intra- or peritumoral low-resistance pulsatile flow signals suggests the malignant nature of the cutaneous lesion. High frequency ultrasound can also be used to study diffuse cutaneous conditions. Among them, ultrasound can provide a valid morphologic representation of psoriatic skin lesions and it is also a noninvasive and accurate method for evaluating the therapeutic efficacy of antipsoriatic drugs. In scleroderma, sonographic findings vary depending on disease activity and the patterns vary; therefore, 20 MHz probes may also prove useful over the other instrumental tools to monitor the disease course and treatment efficacy in focal scleroderma. Other potential applications include allergic dermatitis, nodular erythema, dermatomyosis, sarcoidosis, lymphedema of the limbs and allergologic conditions. Ultrasound can also be used in monitoring the response to or complications of topic drugs administration, and in the follow-up of focal burns., Conclusion: High frequency ultrasound can provide a reliable morphologic representation of skin lesions but it is also an accurate noninvasive tool for monitoring the therapeutic efficacy of drugs administration in focal or diffuse diseases. The application of high frequency studies to dermatology is very challenging. Indeed, the very high frequency probes up to 20 MHz currently available are particularly useful for reliable studies. Contrast-enhanced color and power doppler are very promising techniques. Advancements in technology will improve the correlation of clinical with high frequency ultrasound findings in the assessment of several skin diseases.