Massimo Tonolini

Ultrasound of thyroid, parathyroid glands and neck lymph nodes.

In the past 15xa0years high-frequency B-mode sonography and colour–power Doppler have become the most important and most widely employed imaging modalities for the study of the neck, in particular for thyroid gland, parathyroids and lymph nodes. Sonography allows not only the detection but often also the characterization of the diseases of these organs, distinguishing benign from malignant lesions with high sensitivity and specificity, which could be further improved by the employ of ultrasound contrast agents and harmonic imaging. Although no single sonographic criterion is specific for benign or malignant nature of the lesions, the combination of different signs can be markedly helpful to speed up the diagnostic process. Fine-needle aspiration biopsy (FNAB) remains the most accurate modality for the definitive assessment of thyroid gland nodules and of any doubtful case of nodal disease. In association with clinical findings and serum levels of parathormone, FNAB has specificity close to 100% for the characterization of parathyroid adenomas. A combined approach with sonography and FNAB is generally highly effective.

Radiofrequency thermal ablationof hepatic metastases

Abstract Percutaneous radiofrequency (RF) ablation is a promising therapeutic option for liver metastases, which may result in prolonged survival and chance for cure. Recent technological advancements provide larger coagulation volumes, allowing treatment of medium- and large-size metastases. Candidates are patients with metachronous liver metastases from colorectal or other primary cancers, in whom surgery is contraindicated and with one to four nodules each smaller than approx. 4 cm. We treated 109 patients with 172 colorectal metastases in the liver. Local control was obtained in 70.4% of lesions. Recurrence was significantly more frequent in lesions >3 cm. One major complication occurred (0.6% of sessions), a large bowel perforation requiring surgery. Seven minor complications did not require therapy. New metastases developed at follow-up in 50.4% of patients. Survival rates are 67% and 33% after 2 and 3 years, respectively; estimated median survival being 30 months. RF ablation advantages include minimal-invasiveness (no mortality, significantly lower complications), reduced costs and hospital stays compared to surgery, feasibility in non-surgical candidates, and the potential of repeated treatment if local recurrence occurs or new metastases develop.

Guidance and control of percutaneous treatments with contrast-enhanced ultrasound

Currently, percutaneous interventional modalities such as ethanol injection (PEI) and thermal ablation using different energy sources including radiofrequency (RF), laser, or microwave are widely accepted for minimally invasive treatment of liver tumors [1, 2]. Diagnostic imaging is of paramount importance in all steps of tumor ablative interventions: (1) detection of lesions and selection of patients for treatment; (2) targeting of lesion(s) with optimal positioning of the energy applicator; (3) immediate assessment of therapeutic results, and (4) long-term follow-up. Early detection and accurate assessment of the extent of neoplastic liver disease at the time of diagnosis and on post-treatment follow-up is crucial for optimal patient management. Nowadays it is widely accepted that patients with metachronous liver metastases from colorectal or other primary cancers may undergo RF ablation with curative intention if a maximum of four to five lesions, each smaller than 4 cm, are present. Similarly, patients with chronic liver disease, hepatocellular carcinomas (HCCs) and dysplastic lesions can undergo RF ablation as the only treatment when no more than four to five nodules are detected, and each does not exceed 5-6 cm, in the absence of portal thrombosis and liver function decompensation. Larger hepatocellular carcinomas are usually treated noninvasively by means of combined therapies (chemoembolization, ethanol injection, laser, and radiofrequency). Cross-sectional imaging modalities such as multiphasic contrast-enhanced helical computed tomography (CT) and dynamic gadolinium-enhanced magnetic resonance (MR) imaging provide convenient staging of hepatic and extrahepatic neoplastic involvement. Actually, unenhanced B-mode sonography is the most widely available low-cost imaging modality for the screening of liver disease, but it is less accurate than CT and MR imaging in the detection of focal lesions, particularly of smaller ones. Pretreatment evaluation using contrastenhanced sonography (CEUS) can significantly improve detection and staging of liver tumors particularly for liver metastases. Furthermore, images and/or movie clips attained from pretreatment CEUS studies can be digitally stored and findings compared with those of contrast-enhanced axial imaging for maximization of detection and “mapping” of lesions to be targeted during the operative session. All ablative treatments lead to the disruption of tumor vascularity. The best way to assess noninvasively the efficacy of any percutaneous ablation is the demonstration of blood supply disruption only inside (for HCCs) or also at the periphery (for metastases) of the tumor by means of imaging methods. Whereas a high rate of apparently complete tumor necrosis on initial postablation evaluation is reported in most published series, local recurrences probably resulting from a lack of complete treatment are frequent [3]. Achieving only partial necrosis involves retreatments with increased costs, patient discomfort, greater technical difficulties, and higher rate of failure [4]. In this article we present our experience using CEUS for pretreatment evaluation, intraoperative monitoring, and postablation assessment of therapeutic results.

Guidance of Percutaneous Tumor Ablation Procedures

Diagnostic imaging plays a key role in all steps of radiofrequency (RF) tumor ablation. It is used in the following ways: 1) detection of lesions and selection of patients for treatment; 2) targeting of lesions and guidance of the procedure; 3) immediate assessment of treatment results; 4) long-term follow-up. Conventional, unenhanced ultrasound (US) is widely employed for screening liver disease, but variable sensitivity and well-known drawbacks limit its role in the staging of liver tumors. Furthermore, sonography represents the most commonly used imaging modality for the guidance of percutaneous ablative treatments owing to its availability, rapidity and ease of use. Differentiation of induced necrosis from a viable tumor is not possible with baseline and color Doppler sonography and therefore the immediate and long-term assessment of the therapeutic result is usually accomplished by contrastenhanced helical computer tomography (CT) and magnetic resonance (MR). In our experience, the use of contrastenhanced ultrasound (CEUS) represents a significant improvement over conventional US for each of above-mentioned steps and has proven useful in achieving optimal patient management and treatment results [1].

Ultrasound Imaging in Tumor Ablation

Diagnostic imaging plays a key role in all steps of radiofrequency (RF) tumor ablation: n n1. n nDetection of lesions and selection of patients for treatment; n n n n n2. n nTargeting of lesions and guidance of the procedure; n n n n n3. n nImmediate assessment of treatment result; n n n n n4. n nLong-term follow-up.

Ablation of Liver Metastases

Metastatic liver disease represents one of the most common clinical problems in oncology practice. Multiple treatment options are available including hepatic resection, chemoembolization, intraarterial and systemic chemotherapy, cryotherapy, and radiofrequency ablation (RFA) (1,2).

Thyroid Nodules: Which Sonographic Criteria for Differentiation between Benign and Malignant Lesions?

In the morphological study of thyroid pathology the first crucial differentiation Is between dl..a..s with nodules, single or multiple, and dlffu.. dl..a... without evidence of nodules. However, auoclatlons of one or more nodular lesions with dlffu.. structural change may occur. Nodular thyroid dl..a.. Is much more common than dlffu.. dl..a... Epidemiologic studies estimate that between 4% and 7% of the adult population In the United States and Europe has palpable thyroid nodules, with women being more frequently affected than menl . It is well known that all thyroid diffuse diseases (with the exception of the extremely rare diffuse primary lymphoma) and approximately 90-92% of nodular pathologies are benignl21. Actually, thyroid cancer is rare (estimated annual incidence rate of 5 per 100,000) and accounts for less than 1% of all malignant neoplasms and less than 10% of all palpable thyroid nodules. Therefore, the clinical challenge is to distinguish the few clinically significant malignant nodules from the many benign ones and, thus, to identify those patients for whom surgical excision is strictly indicated. This task is complicated by the fact that most thyroid nodules are clinically occult (less than 1.5cm), but easily detectable by high-resolution sonography (Fig. 1). The question of how to manage these sonographically detected incidentalomas is extremely important. Studies comparing clinical palpation with thyroid imaging show a prevalence of 13% to 50% for the detection of thyroid inctdentalomasv.