Preoperative magnetic resonance and intraoperative ultrasound fusion imaging for real-time neuronavigation in brain tumor surgery.

PURPOSE: Brain shift and tissue deformation during surgery for intracranial lesions are the main actual limitations of neuro-navigation (NN), which currently relies mainly on preoperative imaging. Ultrasound (US), being a real-time imaging modality, is becoming progressively more widespread during neurosurgical procedures, but most neurosurgeons, trained on axial computed tomography (CT) and magnetic resonance imaging (MRI) slices, lack specific US training and have difficulties recognizing anatomic structures with the same confidence as in preoperative imaging. Therefore real-time intraoperative fusion imaging (FI) between preoperative imaging and intraoperative ultrasound (ioUS) for virtual navigation (VN) is highly desirable. We describe our procedure for real-time navigation during surgery for different cerebral lesions. MATERIALS AND METHODS: We performed fusion imaging with virtual navigation for patients undergoing surgery for brain lesion removal using an ultrasound-based real-time neuro-navigation system that fuses intraoperative cerebral ultrasound with preoperative MRI and simultaneously displays an MRI slice coplanar to an ioUS image. RESULTS: 58 patients underwent surgery at our institution for intracranial lesion removal with image guidance using a US system equipped with fusion imaging for neuro-navigation. In all cases the initial (external) registration error obtained by the corresponding anatomical landmark procedure was below 2 mm and the craniotomy was correctly placed. The transdural window gave satisfactory US image quality and the lesion was always detectable and measurable on both axes. Brain shift/deformation correction has been successfully employed in 42 cases to restore the co-registration during surgery. The accuracy of ioUS/MRI fusion/overlapping was confirmed intraoperatively under direct visualization of anatomic landmarks and the error was < 3 mm in all cases (100 %). CONCLUSION: Neuro-navigation using intraoperative US integrated with preoperative MRI is reliable, accurate and user-friendly. Moreover, the adjustments are very helpful in correcting brain shift and tissue distortion. This integrated system allows true real-time feedback during surgery and is less expensive and time-consuming than other intraoperative imaging techniques, offering high precision and orientation.

Virtual navigator automatic registration technology in abdominal application.

Real-time Ultrasound (US) image fusion with a pre-acquired second imaging dataset - Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and/or CT/PET - has become widely used in recent years for both diagnosis and image-guided interventional procedures. Liver and kidneys are the main focused anatomical districts, related to abdominal application. There are still nowadays some drawbacks, regarding the adoption of the fusion imaging technique in everyday practice especially regarding its ease of use and the time needed in order to obtain a precise real-time fusion between US and the second imaging modality. The present work is a preliminary study on the feasibility and practical use of an Automatic registration algorithm for CT-US real-time fusion imaging. Data obtained by tests performed on a Doppler phantom, for the assessment of the precision of the registration procedure and in-vivo Automatic registration tests, are presented.

Percutaneous laser ablation of metastatic lymph nodes in the neck from papillary thyroid carcinoma: preliminary results.

CONTEXT: Percutaneous laser ablation (PLA) may be useful in treating patients with metachronous metastatic lymph nodes in the neck. OBJECTIVE: Our objective was to assess PLA as a treatment of difficult-to-treat metachronous cervical lymph node metastases from papillary thyroid carcinoma. DESIGN AND SETTING: We conducted a retrospective analysis of prospectively collected data at a public hospital. PATIENTS: Fifteen patients with previous resection of papillary thyroid carcinoma with elevated serum levels of thyroglobulin (Tg) or anti-Tg antibodies (TgAbs) and 24 metachronous nodal metastases treated between September 2010 and April 2012 were followed with [¹8F]fluorodeoxyglucose (¹8FDG) positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced ultrasound (CEUS). INTERVENTION: Intervention was PLA. OUTCOME MEASURES: Technique feasibility and technical success were evaluated. Tg/TgAb serum levels and ¹8FDG-PET/CT, and CEUS appearance were assessed at 6 and 12 months and compared with baseline. Complications were recorded. RESULTS: PLA was always feasible, and technical success was achieved in all patients. At 6 months, local control was achieved in 11 of 15 patients (73%), with 6 (40%) having serum Tg/TgAb normalized (P = .017 vs baseline). Whereas 20 of 24 (83%) nodes were negative at ¹8FDG-PET/CT and CEUS (P < .001 vs baseline), 4 were ¹8FDG-PET/CT-positive (3 also CEUS-positive). At the 12-month follow-up, local control was achieved in 10 of 14 patients (71.4%). Sixteen of 20 nodes (80%) were negative at ¹8FDG-PET/CT and CEUS (P < .001 vs baseline), 4 were ¹8FDG-PET/CT-positive (2 also CEUS-positive). Four of 10 (40%) patients had normalization of serum Tg/TgAb (P = .098 vs baseline). No major complications occurred. CONCLUSIONS: PLA is potentially feasible, safe, and effective for the treatment of metachronous cervical nodal metastases from papillary thyroid carcinoma. This procedure may reduce or delay a large number of highly invasive repeat neck dissections.

Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS.

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

Risk of tumour seeding after percutaneous radiofrequency ablation for hepatocellular carcinoma.

BACKGROUND: A recent small study reported a high rate of neoplastic seeding after cooled-tip radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) in patients who had undergone previous needle biopsy. Tumour seeding was associated with subcapsular tumour location, poorly differentiated tumours and a high alpha-fetoprotein (AFP) level. The aim of the present study was to determine the rate of neoplastic seeding after RFA in a large series of unselected patients with HCC who had a long follow-up. METHODS: A total of 1314 patients with 2542 nodules were treated in three centres. Median follow-up was 37 months. Needle biopsy had been performed before RFA in 241 patients (18.3 per cent). The influence of subcapsular location, high AFP level and previous biopsy on risk of tumour seeding was assessed. RESULTS: Neoplastic seeding was identified in 12 patients (0.9 per cent); the rate was comparable at the three centres (0.9, 0.7 and 1.4 per cent). Only previous biopsy was significantly associated with tumour seeding (P = 0.004). CONCLUSION: RFA with a cooled-tip needle was associated with a low risk of neoplastic seeding, even in unselected patients. The use of biopsy before RFA is to be discouraged, particularly when liver transplantation is a possibility at a later date.

Extrahepatic recurrence and second malignancies after treatment of hepatocellular carcinoma: spectrum of imaging findings.

PURPOSE: To describe diagnostic imaging features (with a focus on CT findings) of extrahepatic relapses of treated hepatocellular carcinoma and to propose a post-treatment follow-up protocol. MATERIAL AND METHODS: During a six-year span, 226 patients (aged 32-88 years) with chronic hepatitis/cirrhosis were diagnosed as having hepatocellular carcinoma confined to the liver and treated percutaneously with radiofrequency (RF) ablation. A total of 313 treatment sessions were performed. Post-therapeutic follow-up is based upon clinical evaluation, laboratory and imaging (with CT holding the key role) studies. RESULTS: Mean duration of follow-up was 17 months. After successful treatment, actuarial probability of neoplastic relapse is 30.7% after 1 year and 58.5% after 2 years. Eighty-eight patients had recurrence of hepatocellular carcinoma after a variable time interval (mean 7.3 months). Extrahepatic neoplastic relapse was observed in 14 patients, half of these without active hepatic disease. Distribution of extrahepatic sites of recurrence was as follows: abdominal lymph nodes (6 cases), bone (3), peritoneum (2), adrenal (2), lung (1). Five patients (2.2%) had a second primary neoplasm. CONCLUSIONS: Extrahepatic hepatocellular carcinoma is uncommon and occurs in advanced stages, but may represent a pattern of post-treatment relapse. The distinctive hypervascularity of this tumour histology may be observed in adenopathies and adrenal metastases. Second primary neoplasms should be considered in the differential diagnosis of lesions observed during follow-up.

Ultrasound of thyroid, parathyroid glands and neck lymph nodes.

In the past 15 years 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.

Essential techniques for successful radio-frequency thermal ablation of malignant hepatic tumors.

Radio-frequency thermal ablation is one of the most promising minimally invasive techniques for the treatment of nonresectable hepatic tumors. Essential technical tips to successful radio-frequency ablation therapy were collected from five international experts. They were organized into five categories: understanding the mechanisms and principles of radio-frequency ablation, modulation of tissue physiologic characteristics to increase tumor destruction, strategies of overlapping ablations, strategies to improve ablation according to tumor location, and imaging strategies after ablation to ensure adequate therapy. Established factors for optimal ablation, as well as emerging technical tips, are addressed with illustrations in each section. These essential tips will be very helpful for physicians performing radio-frequency ablation of hepatic tumors.

Percutaneous radio-frequency ablation of hepatic metastases from colorectal cancer: long-term results in 117 patients.

PURPOSE: To describe the results of an ongoing radio-frequency (RF) ablation study in patients with hepatic metastases from colorectal carcinoma. MATERIALS AND METHODS: In 117 patients, 179 metachronous colorectal carcinoma hepatic metastases (0.9-9.6 cm in diameter) were treated with RF ablation by using 17-gauge internally cooled electrodes. Computed tomographic follow-up was performed every 4-6 months. Recurrent tumors were retreated when feasible. Time to new metastases and death for each patient and time to local recurrence for individual lesions were modeled with Kaplan-Meier analysis. Modeling determined the effect of number of metastases on the time to new metastases and death and effect of tumor size on local recurrence. RESULTS: Estimated median survival was 36 months (95% CI; 28, 52 months). Estimated 1, 2, and 3-year survival rates were 93%, 69%, and 46%, respectively. Survival was not significantly related to number of metastases treated. In 77 (66%) of 117 patients, new metastases were observed at follow-up. Estimated median time until new metastases was 12 months (95% CI; 10, 18 months). Percentages of patients with no new metastases after initial treatment at 1 and 2 years were 49% and 35%, respectively. Time to new metastases was not significantly related to number of metastases. Seventy (39%) of 179 lesions developed local recurrence after treatment. Of these, 54 were observed by 6 months and 67 by 1 year. No local recurrence was observed after 18 months. Frequency and time to local recurrence were related to lesion size (P < or =.001). CONCLUSION: RF ablation is an effective method to treat hepatic metastases from colorectal carcinoma.

Percutaneous radio-frequency ablation of liver metastases from breast cancer: initial experience in 24 patients.

PURPOSE: To evaluate the authors' initial experience in a consecutive series of 24 patients with breast cancer liver metastases treated with radio-frequency (RF) ablation. MATERIALS AND METHODS: Twenty-four consecutive patients with 64 metastases measuring 1.0--6.6 cm in diameter (mean, 1.9 cm) underwent ultrasonography-guided percutaneous RF ablation with 18-gauge, internally cooled electrodes. Treatment was performed with the patient under conscious sedation and analgesia or general anesthesia. A single lesion was treated in 16 patients, and multiple lesions were treated in eight patients. Follow-up with serial computed tomography ranged from 4 to 44 months (mean, 10 months; median, 19 months). RESULTS: Complete necrosis was achieved in 59 (92%) of 64 lesions. Among the 59 lesions, complete necrosis required a single treatment session in 58 lesions (92%) and two treatment sessions in one lesion (2%). In 14 (58%) of 24 patients, new metastases developed during follow-up. Ten (71%) of these 14 patients developed new liver metastases. Currently, 10 (63%) of 16 patients whose lesions were initially confined to the liver are free of disease. One patient died of progressive brain metastases. No major complications occurred. Two minor complications were observed. CONCLUSION: On the basis of preliminary study results, percutaneous RF ablation appears to be a simple, safe, and effective treatment for focal liver metastases in selected patients with breast cancer.

Radiofrequency thermal ablation of hepatic metastases.

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.