MR-guided high-intensity focused ultrasound: current status of an emerging technology.

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.

Persistence of the sciatic artery: a case report of a combined (complete and incomplete) type causing leg ischemia.

Persistent sciatic artery is a very uncommon embryologic vascular variant, with a prevalence of 0.05% based on angiographic studies. Two different types of this anomaly can occur, complete or incomplete, on the basis of the relationship between sciatic artery and femoral artery. Although many of these patients are asymptomatic, it may represent a threat to the viability of the lower extremity because of atherosclerotic degeneration resulting in aneurysmal dilatation, occlusive thrombosis, or embolic phenomena with distal complication. We present a case of a 64-year-old man with combined, complete and incomplete, type of persistent sciatic artery causing ischemic ulcer of the first toe.

Liver metastases from colorectal cancer treated with conventional and antiangiogenetic chemotherapy: evaluation with liver computed tomography perfusion and magnetic resonance diffusion-weighted imaging.

OBJECTIVE: The objectives of the study were to determine whether perfusion computed tomography (CT-p) and magnetic resonance diffusion-weighted imaging (MR-DWI) can allow evaluation of the effects of chemotherapy combined with antiangiogenetic treatment on liver metastases in patients with advanced colorectal cancer and to determine if changes in CT-p and MR-DWI correlate with the response to therapy as assessed by conventional Response Evaluation Criteria in Solid Tumors (RECIST). METHODS: Eighteen patients with liver metastases from colorectal cancer underwent CT-p and MR-DWI before and 6 months after chemotherapy and antiangiogenetic treatment. Lesions were classified according to RECIST criteria (complete response [CR], partial response [PR], stable disease [SD], and progressive disease) and calculations of CT-p parameters including blood flow (BF), blood volume (BV), capillary permeability (CP), and MR-DWI apparent diffusion coefficient (ADC) values were performed; RECIST, CT-p, and MR-DWI measurements at baseline and follow-up were tested for statistically significant differences using the paired-samples t test. Baseline and follow-up perfusion parameters of the lesions were also compared on the basis of therapy response assessed by RECIST criteria using independent-samples t test. P < 0.05 was considered indicative of a statistically significant difference for all statistical test. RESULTS: Six patients (6/18; 33.3%) were classified as PR (), and the remaining 12 (12/18; 66.7%) were classified as SD. On a per-lesion basis, 2 (2/32; 6.3%) cannot be identified at follow-up, 6 (6/32; 18.8%) showed a decrease in size of more than 30%, and 24 (24/32; 75%) were substantially stable in size. No cases of progressive disease were demonstrated at follow-up. No statistically significant differences were demonstrated between PR, CR, and SD lesions for BF (P = 0.19), BV (P = 0.14), and ADC (P = 0.68) measurements, whereas CP was significantly higher in CR and PR lesions (P = 0.038). Considering differences between baseline and follow-up values, no statistically significant differences were noted between PR and CR lesions versus SD lesions for CT-p values (BF: P = 0.77; BV: P = 0.15; CP: P = 0.64). A statistically significant difference between PR and CR lesions and SD lesions was noted for ADC values (P = 0.047). CONCLUSION: Both CT-p and MR-DWI can detect therapy-induced modifications in lesion vascularization before significant changes in size are evident.