Search

Purpose: The purpose of this study was to evaluate the feasibility of magnetic resonance-guided focused ultrasound (MRgFUS) ablation for pain palliation and local tumor control in selected patients with unresectable primary pancreatic adenocarcinoma., Materials and Methods: After providing dedicated informed consent, 7 patients with histologically proven unresectable pancreatic adenocarcinoma underwent MRgFUS treatment on a dedicated 3-T unit featuring a dedicated ablation system. All lesions were evaluated for device accessibility before the treatment. Procedures of MRgFUS were performed with the patients under general anesthesia with constant controlled respiration. Clinical assessment included evaluation of symptom severity using a visual analog scale before and after the treatment. Imaging follow-up, including both computed tomographic and magnetic resonance examinations, was performed immediately after the treatment and at 3 and 6 months to evaluate the effects of MRgFUS on the targeted tumor and the occurrence, if any, of procedure-related complications., Results: The MRgFUS ablation was successfully performed in 6 patients; no adverse events were observed during or after the procedure. In a single patient, lesion accessibility was limited at treatment time, and the procedure was suspended. The visual analog scale score decreased in all patients from a mean (SD) of 7 (1) to 3 (1) after the treatment. Follow-up imaging results revealed negligible (n = 1) or no (n = 5) tumor regrowth within the ablation area. One patient died because of a metastatic disease 13 months after the treatment, whereas the other 5 are nonprogressing survivors at 6 and 8 months after the treatment., Conclusions: Our preliminary clinical experience suggests that MRgFUS is a feasible and repeatable ablative technique in selected patients with unresectable and device-accessible pancreatic adenocarcinoma.

Magnetic resonance (MR) imaging-guided focused ultrasound is an alternative noninvasive method for reducing the pain in skeletal metastases. MR imaging-guided focused ultrasound ablation offers several key advantages over other noninvasive treatment modalities. This technology enables the performance of three-dimensional treatment planning with MR imaging and continuous temperature mapping of treated tissue by using MR thermometry, thereby enabling real-time monitoring of thermal damage in the target zone. The concentration of acoustic energy on the intact surface of cortical bone produces a rapid temperature increase that mediates critical thermal damage to the adjacent periosteum, the most innervated component of mature bone tissue. Such thermal ablation has been shown to be an extremely effective approach for pain management. Energy delivered during MR imaging-guided focused ultrasound ablation and accumulated inside the pathologic soft tissue of the metastases can create a variable amount of tissue necrosis. This technique has also a potential role in achieving local tumor control, allowing remineralization of trabecular bone or reduction in lesion size. The current report presents a detailed step-by-step guide for performing MR imaging-guided focused ultrasound ablation of bone metastases, including use of MR thermometry for monitoring treatment, protocol selection for simple palliation of pain or for local tumor control, and a description of imaging features of periosteal neurolysis or metastasis ablation. Two case studies are also presented: in the first, the technique provided palliation of pain in bone metastases, and in the second, the technique achieved tumor control as further proof of primary efficacy. MR imaging-guided focused ultrasound ablation is a promising method for successful palliation of bone metastasis pain and tumor control, because of the bony structure remodeling induced by thermo-related coagulative necrosis.

The concept of ideal tumor surgery is to remove the neoplastic tissue without damaging adjacent normal structures. High-intensity focused ultrasound (HIFU) was developed in the 1940s as a viable thermal tissue ablation approach. In clinical practice, HIFU has been applied to treat a variety of solid benign and malignant lesions, including pancreas, liver, prostate, and breast carcinomas, soft tissue sarcomas, and uterine fibroids. More recently, magnetic resonance guidance has been applied for treatment monitoring during focused ultrasound procedures (magnetic resonance-guided focused ultrasound, MRgFUS). Intraoperative magnetic resonance imaging provides the best possible tumor extension and dynamic control of energy deposition using real-time magnetic resonance imaging thermometry. We introduce the fundamental principles and clinical indications of the MRgFUS technique; we also report different treatment options and personal outcomes.

Objectives: The objectives of this study were to evaluate the efficacy in pain management of magnetic resonance (MR)-guided focused ultrasound for the primary treatment of painful bone metastases and to assess its potential for local control of bone metastases., Materials and Methods: This was a prospective, single-arm research study with approval from the institutional review board. Eighteen consecutive patients (female, 8; male, 10; mean [SD] age, 62.7 [11.5] years) with painful bone metastases were enrolled. The patients were examined clinically for pain severity and pain interference in accordance with the Brief Pain Inventory-Quality of Life criteria before and at each follow-up visit. Computed tomography and MR imaging were performed before and at 1 and 3 months after the magnetic resonance-guided focused ultrasound treatment. The nonperfused volume (NPV) was calculated to correlate the extension of the ablated pathological tissue in the responder and nonresponder patients., Results: No treatment-related adverse events were recorded during the study. The evaluation of pain palliation revealed a statistically significant difference between baseline and follow-up values for pain severity and pain interference (P = 0.001, both evaluations). In the evaluation of local tumor control, we observed increased bone density with restoration of cortical borders in 5 of the 18 patients (27.7%). In accordance with the MD Anderson criteria, complete and partial responses were obtained in 2 of the 18 patients (11.1%) and 4 of the 18 patients (22.2%), respectively. Nonperfused volume values ranged between 20% and 93%. Mean NPV values remained substantially stable after the treatment (P = 0.08). There was no difference in the NPV values between the responder and nonresponder patients (46.7% [24.2%] [25%-90%] versus 45% [24.9%] [20%-93%]; P = 0.7)., Conclusions: Magnetic resonance-guided focused ultrasound can be safely and effectively used as the primary treatment of pain palliation in patients with bone metastases and has a potential role in local tumor control.

Purpose: To evaluate the diagnostic performance and effect on therapeutic management of 64-section computed tomographic (CT) angiography in the assessment of steno-occlusive disease in patients with peripheral arterial disease (PAD), with conventional digital subtraction angiography (DSA) as the reference standard., Materials and Methods: The study protocol was approved by the institutional review board, and written informed consent was obtained from all patients. A total of 212 patients with symptomatic PAD underwent CT angiography and subsequent DSA. For stenosis analysis (≥ 70% stenosis), the arterial bed was divided into 35 segments and evaluated by three readers. Interobserver agreement was determined with generalized κ statistics. Accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were calculated. In addition, according to the TransAtlantic Inter-Society Consensus (TASC) Document on Management of Peripheral Arterial Disease guidelines, treatment recommendations based on CT angiographic and DSA findings were compared. McNemar test was used to prove significant differences between CT angiographic and DSA findings., Results: A total of 7420 arterial segments were evaluated, with excellent agreement between readers (κ ≥ 0.928). On a segmental basis, both sensitivity and specificity for stenosis of 70% or more were at least 96% (3072 of 3113 segments and 4141 of 4279 segments, respectively), with an accuracy of 98% (7213 of 7392 segments), a PPV of 96% (3072 of 3187 segments), an NPV of 99% (3141 of 3187 segments), a PLR of 36.7, and an NLR of 0.013. There was no significant difference between CT angiographic and DSA findings (P = .62-.87). In accordance with TASC II guidelines, 49 patients were referred for conservative treatment, 87 underwent endovascular procedures, 38 underwent surgery, and 17 received hybrid treatment. Therapy recommendations based on CT angiographic findings alone were identical to those based on DSA findings in all but one patient., Conclusion: The diagnostic performance of 64-section CT angiography is excellent in patients with clinical symptoms of PAD. The results can be used to effectively guide therapeutic decision making in these patients., (© RSNA, 2011.)