Gallstone disease in severely obese children participating in a lifestyle intervention program: incidence and risk factors.

INTRODUCTION: Cholelithiasis is increasingly encountered in childhood and adolescence due to the rise in obesity. As in adults, weight loss is presumed to be an important risk factor for cholelithiasis in children, but this has not been studied. METHODS: In a prospective observational cohort study we evaluated the presence of gallstones in 288 severely obese children and adolescents (mean age 14.1±2.4 years, body mass index (BMI) z-score 3.39±0.37) before and after participating in a 6-month lifestyle intervention program. RESULTS: During the lifestyle intervention, 17/288 children (5.9%) developed gallstones. Gallstones were only observed in those losing >10% of initial body weight and the prevalence was highest in those losing >25% of weight. In multivariate analysis change in BMI z-score (odds ratio (OR) 3.26 (per 0.5 s.d. decrease); 95% CI:1.60-6.65) and baseline BMI z-score (OR 2.32 (per 0.5 s.d.); 95% CI: 1.16-4.70) were independently correlated with the development of gallstones. Sex, family history, OAC use, puberty and biochemistry were not predictive in this cohort. During post-treatment follow-up (range 0.4-7.8 years) cholecystectomy was performed in 22% of those with cholelithiasis. No serious complications due to gallstones occurred. CONCLUSION: The risk of developing gallstones in obese children and adolescents during a lifestyle intervention is limited and mainly related to the degree of weight loss and initial body weight.

Ultrasonography is not more reliable than anthropometry for assessing visceral fat in obese children.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Visceral fat accumulation is a risk factor for obesity-related complications. Waist circumference is used in clinical practice to assess visceral adiposity. WHAT THIS STUDY ADDS: Ultrasound is not superior to waist circumference for assessing visceral obesity in obese children. The optimal site for measuring waist circumference in obese children is at the smallest body circumference between xiphisternum and umbilicus. OBJECTIVE: Visceral fat accumulation is a well-established risk factor for obesity-related complications. In children, it has not been determined whether ultrasonography is superior to waist measurement for assessing visceral fat. Moreover, the optimal site for waist measurement has not been determined. DESIGN: In a prospective cohort of 92 severely obese children and adolescents (age 13.9 ± 2.2 years, body mass index z-score 3.29 ± 0.33), we evaluated the performance of ultrasonography and two different methods of waist circumference measurement, using magnetic resonance imaging as the reference standard. RESULTS: Waist circumference, defined as the smallest body circumference between xiphisternum and umbilicus had the strongest correlation with visceral fat quantity (r = 0.69 all, r = 0.68 girls, r = 0.64 boys). It was not outperformed by ultrasonography (r = 0.60 all, r = 0.62 girls, r = 0.50 boys) and correlated significantly better than the World Health Organization standard for waist measurement, midway between lower margin of the last rib and the crest of the ilium, (r = 0.51 all, r = 0.39 girls, r = 0.46 boys). CONCLUSIONS: Waist circumference measurement, defined as the smallest body circumference between xiphisternum and umbilicus, is the preferred non-invasive technique for daily clinical practice to assess visceral fat accumulation in severely obese children and adolescents. There is no place for ultrasonography for the quantification of visceral fat in this group.

Abnormal radiological findings and a decreased carbon monoxide transfer factor can persist long after the acute phase of Legionella pneumophila pneumonia.

Pulmonary abnormalities may persist long after the acute phase of legionnaires disease (LD). In a cohort of 122 survivors of an outbreak of LD, 57% were still experiencing an increased number of symptoms associated with dyspnea at a mean of 16 months after recovery from acute-phase LD. For 86 of these patients, additional evaluation involving high-resolution computed tomography (HRCT) of the lung revealed pulmonary abnormalities in 21 (24%); abnormal HRCT findings generally presented as discrete and multiple radiodensities. Residual pulmonary abnormalities were associated with a mean reduction of 20% in the gas transport capacity of the lung. This latter sign could not be used to explain the increased symptoms of dyspnea reported by patients. Receipt of mechanical ventilation during the acute phase of LD, delayed initiation of adequate antibiotic therapy, and chronic obstructive pulmonary disease were identified as risk factors for the persistence of lung abnormalities.

Abnormal bone scans in anterior cruciate ligament deficiency indicate structural and functional abnormalities.

Many patients with anterior cruciate ligament (ACL) deficiency have an abnormal bone scan. This finding has not yet been explained. Suggested explanations include intra-articular (structural) or kinematic (functional) abnormalities. We examined the relationship between bone scintigraphy and cartilage degeneration or meniscal lesions in the ACL-deficient knee in 95 consecutive patients who had bone scintigraphy 1-3 days prior to arthroscopic ACL reconstruction. Intra-articular abnormalities of the knee did not explain all scintigraphic patterns of this study. We did not find clinically useful positive predictive values for scintigraphic patterns considered to indicate cartilage degeneration or a lateral meniscus lesion. A clinically useful positive predictive value was found only for medial meniscus lesions when time since ACL rupture was more than 18 months, and for local cartilage degeneration when markedly increased uptake was seen when time since ACL rupture was more than 4 months. Considering these findings, alternative explanations are discussed, based on specific aspects of abnormal kinematics and adaptive bone metabolism of the ACL-deficient knee.

Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length.

Tibial bone tunnels were examined with bone scans 2 years after patella ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r = 0.64, P < 0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r = 0.59 P < 0.001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation is more than 14 mm below the joint.

Contrast-enhanced MR imaging of the liver.

Postcontrast images with a 0.1 mmol/kg dose of a gadolinium chelate with extracellular distribution, when acquired dynamically during breath holding, can improve both differential diagnosis and lesion recognition in liver MR imaging. Initial results at 0.3 mmol/kg, compared with 0.1 mmol/kg, suggest a substantial improvement in lesion identification at the high dose, as assessed by using signal intensity difference divided by noise. Of the gadolinium chelates with predominantly renal excretion, only gadoteridol is presently approved in the United States at the high dose, with limited clinical evaluation for liver imaging performed to date. For linear chelates, such as gadopentetate dimeglumine and gadodiamide injection, the degree to which release of free gadolinium ion occurs is a possible issue because of lower in vivo stability (42,43). Preliminary results with hepatobiliary gadolinium chelates and iron particulate agents are favorable with regard to efficacy, although these agents remain in clinical trials.

Intraluminal contrast agents for MR imaging of the abdomen and pelvis.

Magnetic resonance (MR) imaging of the abdomen and pelvis with use of gastrointestinal (GI) contrast agents is slowly emerging as a valuable diagnostic tool. In the past few years, considerable effort has been expended on developing an oral contrast agent to serve as a bowel marker during abdominal and pelvic imaging. Four major categories of agents have been studied: compounds with positive contrast-enhancing characteristics (ie, which increase signal intensity), which may be either miscible or immiscible with bowel contents, and compounds with negative contrast-enhancing characteristics (ie, which decrease signal intensity), which also may be miscible or immiscible. Compared with precontrast images, MR images acquired after administration of GI contrast agents have shown increased anatomic delineation of the bowel lumen, pancreas, and paraaortic nodes, allowing increased detection of pancreatic lesions, improved assessment of bowel wall lesions, and distinction between intrahepatic and extrahepatic lesions. This review focuses on the general physics and requirements for intraluminal GI contrast media for MR imaging, the currently used intraluminal agents and their regulatory status, current and near-future availability, and cost considerations.