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Quantitative MRI and ultrasound biomarkers of liver fibrosis have become important tools in the diagnosis and clinical management of children with chronic liver disease (CLD). In particular, MR elastography is now routinely performed in clinical practice to evaluate the liver for fibrosis. Ultrasound shear-wave elastography has also become widely performed for this purpose, especially in young children. These noninvasive methods are increasingly used to replace liver biopsy for the diagnosis, quantitative staging, and treatment monitoring of patients with CLD. Although ultrasound has the advantages of portability and lower equipment cost than MRI, available evidence indicates that MRI may have greater reliability and accuracy in liver fibrosis evaluation. In this AJR Expert Panel Narrative Review, we describe how, why, and when to use MRI- and ultrasound-based elastography methods for liver fibrosis assessment in children. Practical approaches are discussed for adapting and optimizing these methods in children, with consideration of clinical indications, patient preparation, equipment requirements, and acquisition technique, as well as pitfalls and confounding factors. Guidance is provided for interpretation and reporting, and representative case examples are presented.

Objective: The purpose of this article is to evaluate the diagnostic performance of transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index in assessing fibrosis in patients with chronic hepatitis C by using histologic Metavir scores as reference standard., Subjects and Methods: Consecutive patients with chronic hepatitis C scheduled for liver biopsy were enrolled. Liver biopsy was performed on the same day as transient elastography and real-time strain elastography. Transient elastography and real-time strain elastography were performed in the same patient encounter by a single investigator using a medical device based on elastometry and an ultrasound machine, respectively. Diagnostic performance was assessed by using receiver operating characteristic curves and area under the receiver operating characteristic curve (AUC) analysis., Results: One hundred thirty patients (91 men and 39 women) were analyzed. The cutoff values for transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index were 6.9 kPa, 1.82, and 0.37, respectively, for fibrosis score of 2 or higher; 7.3 kPa, 1.86, and 0.70, respectively, for fibrosis score of 3 or higher; and 9.3 kPa, 2.33, and 0.70, respectively, for fibrosis score of 4. AUC values of transient elastography, real-time strain elastography, aspartate-to-platelet ratio index were 0.88, 0.74, and 0.86, respectively, for fibrosis score of 2 or higher; 0.95, 0.80, and 0.89, respectively, for fibrosis score of 3 or higher; and 0.97, 0.80, and 0.84, respectively, for fibrosis score of 4. A combination of the three methods, when two of three were in agreement, showed AUC curves of 0.93, 0.95, and 0.95 for fibrosis scores of 2 or higher, 3 or higher, and 4, respectively., Conclusion: Transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index values were correlated with histologic stages of fibrosis. Transient elastography offered excellent diagnostic performance in assessing severe fibrosis and cirrhosis. Real-time elastography does not yet have the potential to substitute for transient elastography in the assessment of liver fibrosis.

Objective: The purpose of this article is to assess the differences, if any, in the values of carotid artery stiffness parameters between HIV-infected subjects without known cardiovascular disease (CVD) or carotid artery plaques and HIV-uninfected control subjects matched for sex, age, body mass index, and other CVD risk factors (i.e., hypertension, hypercholesterolemia, diabetes, and cigarette smoking). Arterial stiffness is emerging as a predictor of CVD risk. By recording the blood pressure, an automated echo-tracking system implemented in ultrasound equipment allows evaluation of arterial stiffness., Subjects and Methods: Fifty-four HIV-infected patients without a history of CVD were closely matched for sex, age, body mass index, and CVD risk factors to 54 HIV-uninfected control subjects on an individual basis. Ultrasound studies of carotid artery stiffness parameters were performed using ultrasound equipment with a linear broadband high-frequency transducer. Carotid intima-media thickness was also measured. Repeatability between operators was assessed. Nonparametric Mann-Whitney U test, chi-square statistics, Fisher exact test, Pearson correlation coefficient, and intraclass correlation coefficient were used for statistical analysis. A p value less than 0.05 was considered statistically significant., Results: Except for arterial compliance in HIV-infected subjects, arterial stiffness parameters were correlated with age in both groups. Compared with matched control subjects, HIV-infected subjects showed lower arterial compliance parameter values (0.95 [interquartile range, 0.78-1.23] vs 0.76 [interquartile range, 0.62-1.00]; p = 0.0009), whereas other parameters were similar. Repeatability between operators was good., Conclusion: HIV-infected subjects have an arterial compliance significantly lower than that of control subjects. The impairment of carotid artery distensibility may contribute to subclinical atherosclerosis.

Objective: The purpose of this study was to assess, with contrast-enhanced CT or MRI as the reference imaging technique, the diagnostic performance of low-mechanical-index contrast-enhanced sonography in detecting local tumor progression after percutaneous radiofrequency ablation of renal tumors., Materials and Methods: Twenty-nine patients with 30 renal tumors (18 men, 11 women; mean age, 73 years; range, 53-83 years) underwent percutaneous radiofrequency ablation at a single center between March 1998 and January 2007. The imaging follow-up schedule was both contrast-enhanced sonography and CT or MRI 4 months after completion of treatment and every 4 months for the first year. Thereafter, the follow-up schedule was contrast-enhanced sonography every 4 months with CT or MRI every 8 months. The chi-square test with Yates correction was used to evaluate positive and negative predictive values and accuracy., Results: One patient was scheduled to undergo surgical resection, and another patient was lost to follow-up. Twenty-seven patients with 28 renal tumors participated in follow-up. The concordance between contrast-enhanced sonographic and CT or MRI findings was 100% for 27 of 28 tumors (96.4%) that had a hypervascular pattern before treatment. In the case of the tumor that was hypovascular at imaging performed before percutaneous radiofrequency ablation, local tumor progression was missed at contrast-enhanced sonography. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of contrast-enhanced sonography were 96.6%, 100%, 100%, 95.8%, and 98.1%., Conclusion: Contrast-enhanced sonography is an effective alternative to CT and MRI in the follow-up of renal tumors managed with percutaneous radiofrequency ablation.

Objective: The purposes of this study were to assess the feasibility of a sonographic training program at a district hospital in a developing country and to evaluate the effect of the program on public health care services., Subjects and Methods: A sonographic training program is being conducted on Pemba Island, Tanzania. A maximum of 10 trainees participate in the program. Courses in sonography conducted by European physicians are scheduled every 4 months for 2 consecutive weeks each time. The sonographic training program lasts 5 years and is divided into three stages in which basic, advanced, and specialized courses are organized. At the end of every course, the trainees take a multiple-choice test (score, 1-10) and a practical test with patients (score, 1-5). To advance to the next stage, a trainee needs a score of at least 7 on the theory test and at least 3 on the practical., Results: Three courses have been completed. The total mean scores on the multiple-choice test were 7.4 (range, 6.5-9) at the end of the first course, 7.3 (range, 6.5-8.5) at the end of the second course, and 6.2 (range, 4.0-9.5) at the end of the third course. A shortage of electricity hindered the practical test after the first and second courses. At the end of the third course, the total mean score on the practical was 3.5 (range, 1.5-5.0). Seven of 10 trainees were admitted to the second year of the sonographic training program. The mean monthly hospital earnings during the three-course period were 673,200 Tanzanian shillings., Conclusion: Sonography is an affordable technology for developing countries. Training in sonography should be included in the planning of long-term projects in which multiple access and feedback are provided in the same area.

Objective: The aim of this study was to report 13 years of experience in the management of multiple pyogenic liver abscesses with only percutaneous needle aspiration of the abscess cavities under sonographic guidance., Materials and Methods: From December 1991 to October 2004, 39 consecutively registered patients (29 men and 10 women; age range, 37-82 years; mean age, 64 years) with 118 pyogenic liver abscesses were treated with sonographically guided percutaneous needle aspiration at our institution. The number of pyogenic liver abscesses per patient ranged from two to 15 (mean, 3.0)., Results: Eighty-seven percutaneous needle aspirations were performed on 39 patients with 118 pyogenic liver abscesses (range, 1-4 aspirations per patient; mean, 2.2 aspirations per patient). Because they were close to another aspirated abscess in the right lobe of the liver, 31 (26.3%) of 118 abscesses were aspirated without removal of the needle from the liver. Thirty-six (92.3%) of 39 patients were treated with a single aspiration of an abscess in a single session. The other three patients needed two aspiration sessions. No patient needed imaging-guided percutaneous catheter drainage or open surgical drainage. Complete reconstitution of liver parenchyma occurred within a maximum of 80 days. No abscesses recurred during the follow-up period, which ranged from 7 to 42 months (mean, 18 months)., Conclusion: Percutaneous needle aspiration of multiple pyogenic abscesses under sonographic guidance is a safe, effective, and low-cost procedure. In our experience, percutaneous needle aspiration was acceptable to patients. Our data suggest that a trial of percutaneous needle aspiration should always be undertaken before catheter drainage or surgery.

Objective: Our objective was to report the complications that occurred in a large series of patients with primary or metastatic liver tumors treated with percutaneous saline-enhanced radiofrequency ablation under sonographic guidance at a single center during 3 years of experience., Subjects and Methods: Between September 2000 and October 2003, 336 consecutive patients (221 men and 115 women; age range, 44-78 years; mean, 67 years) with 407 malignant liver tumors were treated at our institution using radiofrequency ablation. Of these patients, 287 had hepatocellular carcinoma from cirrhosis, 47 had liver metastases (38 from colon, six from breast, two from lung, and one from cutaneous melanoma), and two had primary cholangiocarcinoma. Adverse events related to radiofrequency ablation were prospectively recorded., Results: The number of sessions performed was 375 (39 patients had two sessions). The number of patients with major complications, including death, was three (0.9%). The overall mortality rate was 0.3% (1/336). One patient died because of worsening liver decompensation. Two other major complications occurred. In one patient (0.3%), liver abscess and sepsis developed and were successfully treated with percutaneous sonography-guided needle (18-gauge) aspiration and IV antibiotics. Mild posttreatment ascites occurred in one patient (0.3%). One patient showed self-limiting subcutaneous cellulitis along the electrode-needle path that healed in 2 weeks. Fever lasting 1-3 days and pain lasting 12-24 hr were observed in 141 patients (42%) and 211 patients (63%), respectively. So far, no cutaneous or abdominal wall seeding has been observed clinically or sonographically., Conclusion: Radiofrequency ablation of liver tumors can be considered safe. Life-threatening acute liver failure can be considered a rare possible complication.

Objective: We sought to investigate the efficacy of contrast-enhanced sonography using a second-generation contrast agent for the evaluation of hepatocellular carcinoma in patients with cirrhosis by comparing the results to those obtained with contrast-enhanced helical CT., Subjects and Methods: Between October 2002 and March 2003, 74 patients with cirrhosis (60 men and 14 women; age range, 47-80 years; mean age, 67 years) who had a single nodule of hepatocellular carcinoma were selected to be studied from a cohort of 437 patients with cirrhosis. The size range of the 74 nodules was 9-65 mm (mean, 28.2 mm). Twenty-eight (38%) were 20 mm smaller (range, 9-20 mm; mean, 16.6 mm), and 46 (62%) were larger than 20 mm (range, 21-65 mm; mean, 35.2 mm). Contrast-enhanced sonography was performed at a low mechanical index after IV administration of the contrast agent SonoVue. CT scans were obtained in all patients. The enhancement pattern related to tumor hypervascularity was analyzed. The chi-square test was used for statistical analysis., Results: For the 28 hepatocellular carcinomas 20 mm or smaller, contrast-enhanced sonography showed 15 (53.6%) as hypervascular and 10 (35.7%) as avascular; three (10.7%) carcinomas were missed. On CT, 12 (42.9%) of the 28 hepatocellular carcinomas appeared hypervascular, 13 (46.4%) appeared hypovascular, and three (10.7%) were missed. For the 46 hepatocellular carcinomas larger than 20 mm, contrast-enhanced sonography showed 42 (91.3%) as hypervascular and four (8.7%) as avascular. On CT, 35 (76.1%) hepatocellular carcinomas appeared hypervascular, eight (17.4%) appeared hypovascular, and three (6.5%) were missed. Differences between CT appearance of hepatocellular carcinomas and contrast-enhanced sonographic appearance of the carcinomas were not statistically significant. Concordance between contrast-enhanced sonographic and CT appearances was observed in 61 (82.4%) of 74 cases., Conclusion: Contrast-enhanced sonography is similar to CT for detecting hepatocellular carcinoma hypervascularity. It could be complementary to conventional unenhanced sonography for evaluation of liver nodules.

Objective: The purpose of our study was to analyze the efficacy, side effects, and short-term complications of saline-enhanced percutaneous radiofrequency ablation performed under sonographic guidance in a series of cirrhotic patients with hepatocellular carcinoma. SUBJECTS AND METHODS. Between September 2000 and June 2002, 84 patients (55 men and 29 women) with cirrhosis who ranged in age from 48 to 74 years (mean age, 64 years) and who had 95 hepatocellular carcinomas (seven patients had two tumors and two patients had three tumors) were treated with high frequency-induced thermotherapy. The diameters of the tumors ranged from 1.5 to 8.5 cm (mean, 3.6 cm). The efficacy of radiofrequency ablation was evaluated with triphasic contrast-enhanced CT performed 4 weeks after the procedure., Results: Posttreatment CT showed complete necrosis in 73 (77%) of 95 hepatocellular carcinomas in 62 patients. Complete necrosis based on tumor size was seen in 40 (95%) of 42 tumors with diameters equal to or smaller than 3 cm, 32 (71%) of 45 tumors with diameters between 3.1 and 5.0 cm, and one (12%) of eight tumors with diameters larger than 5.0 cm. Twenty-two hepatocellular carcinomas showed incomplete necrosis. None of the patients experienced major complications. Four patients were lost to follow-up. The length of the follow-up period ranged from 4 to 22 months (mean, 10 months). One patient died 8 months after the radiofrequency ablation treatment. All the remaining patients are still alive. During the follow-up period, eight (10%) of 80 patients showed a local recurrence on sonography and CT., Conclusion: Our experience suggests that percutaneous radiofrequency ablation of hepatocellular carcinoma with high frequency-induced thermotherapy is safe and effective in the treatment of hepatocellular carcinomas equal to or smaller than 3 cm, fairly effective for hepatocellular carcinomas between 3 and 5 cm, and ineffective for tumors larger than 5 cm.