Thermal ablation of liver metastases from colorectal cancer: radiofrequency, microwave and laser ablation therapies.

Surgery is currently considered the treatment of choice for patients with colorectal cancer liver metastases (CRLM) when resectable. The majority of these patients can also benefit from systemic chemotherapy. Recently, local or regional therapies such as thermal ablations have been used with acceptable outcomes. We searched the medical literature to identify studies and reviews relevant to radiofrequency (RF) ablation, microwave (MW) ablation and laser-induced thermotherapy (LITT) in terms of local progression, survival indexes and major complications in patients with CRLM. Reviewed literature showed a local progression rate between 2.8 and 29.7 % of RF-ablated liver lesions at 12-49 months follow-up, 2.7-12.5 % of MW ablated lesions at 5-19 months follow-up and 5.2 % of lesions treated with LITT at 6-month follow-up. Major complications were observed in 4-33 % of patients treated with RF ablation, 0-19 % of patients treated with MW ablation and 0.1-3.5 % of lesions treated with LITT. Although not significantly different, the mean of 1-, 3- and 5-year survival rates for RF-, MW- and laser ablated lesions was (92.6, 44.7, 31.1 %), (79, 38.6, 21 %) and (94.2, 61.5, 29.2 %), respectively. The median survival in these methods was 33.2, 29.5 and 33.7 months, respectively. Thermal ablation may be an appropriate alternative in patients with CRLM who have inoperable liver lesions or have operable lesions as an adjunct to resection. However, further competitive evaluation should clarify the efficacy and priority of these therapies in patients with colorectal cancer liver metastases.

Comparative study between mobile computed radiography and mobile flat-panel radiography for bedside chest radiography: impact of an antiscatter grid on the visibility of selected diagnostically relevant structures.

OBJECTIVES: The objective of this study was to evaluate the diagnostic performance of 2 different imaging systems in adult bedside chest radiography and the impact on the visibility of selected diagnostically relevant structures in the images acquired with these systems, with and without an antiscatter grid. MATERIALS AND METHODS: We acquired bedside chest radiographs of 103 intensive-care patients (36 women, 67 men; age range, 17-90 years; mean age, 66.4 years) using 4 acquisition techniques (computed radiography [CR] and digital radiography [DR], with and without grid). Image quality was evaluated independently by 4 radiologists using a 9-point visibility scale. Evaluated were lung parenchyma, soft tissues, thoracic spine, foreign bodies, and the overall image quality. Interobserver agreement and differences between the systems were tested using an interclass correlation (ICC) test. Mean scores were compared using the analysis of variance, followed by the post hoc pairwise testing (the Tukey test) in case of multiple group comparisons and by the Student t test in case of single group comparisons (P < 0.05, significant). RESULTS: The image quality of the structures evaluated in the DR images with a grid was significantly higher than that obtained without a grid (P < 0.001) for all structures. The use of a grid in CR significantly improved the overall image quality, lung parenchyma, and soft tissue delineation (P < 0.001). Foreign body delineation, however, was significantly better in the CR images obtained without a grid (P < 0.001), whereas the 2 systems showed no significant difference regarding thoracic spine delineation (P = 0.554). The scores of the DR images were significantly higher than those of the CR images for all structures. The interobserver agreement was substantial for lung parenchyma (ICC, 0.77), soft tissue (ICC, 0.78), thoracic spine (ICC, 0.80), and the overall image quality (ICC, 0.78) and was almost perfect for foreign bodies (ICC, 0.81). CONCLUSIONS: The use of an antiscatter grid significantly improved the image quality of bedside DR radiographs. A similar effect was seen with CR radiographs but only for lung parenchyma, soft tissue, and the overall image quality. Mobile DR outperformed CR in all structures.

Dual-energy CT for the assessment of chronic myocardial infarction in patients with chronic coronary artery disease: comparison with 3-T MRI.

OBJECTIVE: The purpose of this article is to compare the performance of dual-energy CT with that of 3-T MRI with late enhancement for the detection of chronic myocardial infarction during first-pass coronary CT angiography (CTA). SUBJECTS AND METHODS: Thirty-six patients underwent coronary CTA for the assessment of coronary bypass graft patency on a first-generation dual-source CT scanner in dual-energy mode. Gray-scale images (100 kV, 140 kV, and blended virtual 120 kV) were assessed for areas of hypodense myocardium during the arterial phase. In addition, a color-coded map of myocardial iodine distribution was calculated from the dual-energy data for perfusion analysis. Dual-energy CT data were compared with data from 3-T MRI with late enhancement, which served as the reference standard for scar detection using the American Heart Association's 17-segment model of the left ventricle. RESULTS: One hundred one (17%) of 612 myocardial segments in 22 (61%) of 36 patients showed late enhancement on MRI. Although myocardial iodine mapping was prone to artifacts, mostly arising from sternal wires (70% sensitivity), 100-kV gray-scale images showed the highest sensitivity (80%) for the detection of myocardial scar. Blended virtual 120-kV images with lower noise and higher resolution had the best diagnostic accuracy (77% sensitivity, 97% specificity, 85% positive predictive value, 96% negative predictive value, and 94% accuracy). CONCLUSION: Detection of chronic myocardial infarction on color-coded iodine distribution analysis with first-generation dual-energy CT is impeded by thoracic metallic devices. This group of patients benefits more from adequate blending of high- and low-kilovoltage gray-scale images. Further technical improvements are desirable to lower artifact burden and improve sensitivity on myocardial iodine distribution mapping.

Cardiac (31)P-MRS compared to echocardiographic findings in patients with hypertensive heart disease without overt systolic dysfunction--preliminary results.

PURPOSE: To evaluate changes in high energy phosphate (HEP) metabolism in patients with hypertension and diastolic dysfunction but with normal LVEF>55% assessed by echocardiography and tissue Doppler. MATERIAL AND METHODS: 20 patients (16 men and 4 women, mean age 57+/-13 years) were studied with phosphorus magnetic resonance spectroscopy and echocardiography. MRS was performed at 1.5T using an ECG-gated CSI sequence with nuclear Overhauser effect. According to echocardiographical findings 12 patients were found to have a diastolic dysfunction, whereas 8 patients were identified as normal, serving as control group in the following statistical analysis. All patients had normal systolic function (LVEF>55%).Statistical analysis was made by using mean+/-S.D. for description of the data, Spearman correlation and two-tailed Student's t-test for independent samples. RESULTS: No differences were found in weight, age, LVEF, endsystolic volume, end-diastolic volume, cardiac output and BNP levels between patients and control group. Myocardial mass at end-diastole correlated significantly with PCr/ATP ratio (r=-0.66; p=0.04) in patients and control group. Myocardial PCr/ATP ratio in patients was significantly decreased compared to controls (1.21+/-0.22 vs. 1.54+/-0.24; p=0.006). CONCLUSIONS: Cardiac (31)P-MRS might offer a noninvasive means for detecting early states of heart failure in hypertensive patients.