Differences in MRI findings between subgroups of recent-onset childhood arthritis.

BACKGROUND: MRI is sensitive for joint inflammation, but its ability to separate subgroups of arthritis in children has been questioned. Infectious arthritis (IA), postinfectious arthritis (PA), transient arthritis (TA) and juvenile idiopathic arthritis (JIA) are subgroups that may need early, different treatment. OBJECTIVE: To determine whether MRI findings differ in IA, PA/TA and JIA in recent-onset childhood arthritis. MATERIALS AND METHODS: Fifty-nine children from a prospective study of incidence of arthritis (n = 216) were, based on clinical and biochemical criteria, examined by MRI. Joint fluid, synovium, bone marrow, soft tissue and cartilage were scored retrospectively and analysed by Pearson chi-square test and logistic regression analysis. RESULTS: Fifty-nine children had MRI of one station. IA was suggested by bone marrow oedema (OR 7.46, P = 0.011) and absence of T1-weighted and T2-weighted low signal intensity synovial tissue (OR 0.06, P = 0.015). Furthermore, soft-tissue oedema and reduced contrast enhancement in the epiphyses were more frequent in children with IA. JIA correlated positively with low signal intensity synovial tissue (OR 13.30, P < 0.001) and negatively with soft-tissue oedema (OR 0.20, P = 0.018). No significant positive determinants were found for PA/TA, but bone marrow oedema, soft-tissue oedema, irregular thickened synovium and low signal intensity synovial tissue was less frequent than in IA/JIA. CONCLUSION: In children with high clinical suspicion of recent onset arthritis, there was a significant difference in the distribution of specific MRI features among the diagnostic groups.

[Radiation protection of childrens' chest during high resolution CT of the lungs]. / Strålebeskyttelse av barns bryst ved høyoppløselig CT av lungene.

BACKGROUND: The Norwegian Radiation Protection Authority recommends bismuth to protect radiosensitive surface organs during CT imaging. A study based on the use of phantoms was therefore initiated to investigate the usefulness of this protection on the breasts of young girls undergoing high-resolution computed tomography (HRCT) of the chest. MATERIAL AND METHODS: Shields covered with one, two or three layers of bismuth were placed on a homogenous phantom. CT numbers (pixel values in the images which describe the density of the tissue imaged), noise and artifacts were evaluated from the images of the phantom. Dosimeters were used for dose measurements in an anthropomorphic phantom of a child. RESULTS: Areas close to the shield in the images of the phantom had CT numbers up to 33 % higher with two and three layers of bismuth than in the images without shielding. With one layer the CT numbers were up to 8 % higher. Noise in the same area was up to 56 % higher with two and three layers of bismuth than without, and up to 14 % higher with one layer. The surface dose in the breast region was reduced with 30 % with one layer of bismuth, 45 % with two and 75 % with three layers of bismuth. INTERPRETATION: Shielding with one layer of bismuth seems to have little effect on the CT images. The Department of pediatric radiology at Ullevaal University Hospital now uses bismuth protection with one layer as a routine during HRCT of girls up to 16 years of age.

Childhood osteomyelitis-incidence and differentiation from other acute onset musculoskeletal features in a population-based study.

BACKGROUND: Osteomyelitis can be difficult to diagnose and there has previously not been a prospective approach to identify all children in a defined geographic area. The aim of this study was to assess the annual incidence of osteomyelitis in children, describe the patient and disease characteristics in those with acute (< 14 days disease duration) and subacute osteomyelitis (> or = 14 days disease duration), and differentiate osteomyelitis patients from those with other acute onset musculoskeletal features. METHODS: In a population-based Norwegian study physicians were asked to refer all children with suspected osteomyelitis. Children with osteomyelitis received follow-up at six weeks, six months and thereafter as long as clinically needed. RESULTS: The total annual incidence rate of osteomyelitis was 13 per 100,000 (acute osteomyelitis 8 and subacute osteomyelitis 5 per 100,000). The incidence was higher in patients under the age of 3 than in older children (OR 2.9, 95%: CI 2.3-3.7). The incidence of non-vertebral osteomyelitis was higher than the incidence of vertebral osteomyelitis (10 vs. 3 per 100 000; p = .002). Vertebral osteomyelitis was more frequent in girls than in boys (OR 7.0, 95%: CI 3.3-14.7). ESR > or = 40 mm/hr had the highest positive predictive laboratory value to identify osteomyelitis patients at 26% and MRI had a positive predictive value of 85%. Long-bone infection was found in 16 (43%) patients. ESR, CRP, white blood cell count, neutrophils and platelet count were higher for patients with acute osteomyelitis than for patients with subacute osteomyelitis. Subacute findings on MRI and doctor's delay were more common in subacute osteomyelitis than in acute osteomyelitis patients. Blood culture was positive in 26% of the acute osteomyelitis patients and was negative in all the subacute osteomyelitis patients. CONCLUSION: The annual incidence of osteomyelitis in Norway remains high. ESR values and MRI scan may help to identify osteomyelitis patients and differentiate acute and subacute osteomyelitis.

Bowel magnetic resonance imaging of pediatric patients with oral mannitol MRI compared to endoscopy and intestinal ultrasound.

The purpose of this study was to assess the sensitivity, specificity, and diagnostic accuracy of magnetic resonance imaging (MRI) in pediatric patients with clinical suspicion of inflammatory bowel disease (IBD) by comparing MRI and ultrasound (US) to endoscopy, the gold standard. A median volume of 300 ml of mannitol in a 15% [corrected] watery solution were ingested by 43 children prior to examination. The 53 MRI examinations were compared with 20 endoscopies and 41 US of the terminal ileum. The outcomes were MRI quality; pathologic findings; level of adverse events; and concordance between endoscopy, MRI, and US estimated by kappa statistics. The ileum and terminal ileum were very good or excellently imaged in approximately 80% of cases. Wall thickening and enhancement were most frequent in the terminal ileum. MRI compared with endoscopy had a sensitivity of 81.8% [95% confidence interval (CI)], specificity of 100%, diagnostic accuracy of 90%, and kappa value of 0.80 (95% CI), indicating a good degree of concordance. A similar degree of concordance was achieved between US and endoscopy. In spite of the frequent adverse reactions, such as diarrhea and nausea, half of the patients were prepared to repeat the examination. The results of MRI are concordant with endoscopy and US of the terminal ileum.