Pediatric emergencies: thoracic emergencies

Emergencies always require rapid diagnosis and an urgent or semi-urgent medical, interventional, or surgical action. In most cases radiology plays an essential role in making an accurate diagnosis. Reviewing the causes of acute respiratory pathology in the different pediatric age groups, we thought it would be interesting to divide the pathologies into two main parts: one part concerning pathologies involving the air flow and the other part concerning pathology affecting the pulmonary parenchyma. We acknowledge, however, that both conditions can occur concomitantly. The esophagus is another anatomic structure in the thorax that can be responsible for acute pathology in children. Acute pathology predominantly involving the air flow can be intrinsic and/or extrinsic, affecting the upper airways, trachea, main and segmental bronchi, and the small airways. Acute lung pathology can be congenital, infectious, or less frequently, tumoral or traumatic in children. Pleural pathology and cardiogenic emergencies are discussed also. Acute esophageal pathology is discussed briefly. Electronic Publication     

Tumour necrosis factor alpha increases melphalan concentration in tumour tissue after isolated limb perfusion

Several possible mechanisms for the synergistic anti-tumour effects between tumour necrosis factor alpha (TNF-alpha) and melphalan after isolated limb perfusion (ILP) have been presented. We found a significant sixfold increase in melphalan tumour tissue concentration after ILP when TNF-alpha was added to the perfusate, which provides a straightforward explanation for the observed synergism between melphalan and TNF-alpha in ILP.     

Quantitative single-voxel spectroscopy: the reciprocity principle for receive-only head coils

PURPOSE: To correct MR spectra for local changes in the coil sensitivity for a widely used coil setup, consisting of a transmitting body coil and a receive-only head coil. MATERIALS AND METHODS: The method relies on the reciprocity principle for the body coil and a correction factor for signal amplitudes between body coil and head coil. The correction is based either on the local flip angle dependence of the stimulated echo acquisition mode signal (TFC) or on the automatic RF calibration (RFC). Water phantoms of different volumes were used to simulate variable coil loads, and B1 field inhomogeneities were assessed by varying the voxel position. Furthermore, the correction was tested by longitudinal measurements in one volunteer. RESULTS: The correction in vitro yields a reduction of the variation coefficient of the water signal by about 77% (TFC) and 66% (RFC) for different coil loads, as well as 55% (TFC) for variable voxel positions. Slightly lower reductions were assessed for the variation coefficients of the metabolite signals in vivo. CONCLUSION: This approach adequately compensates for local changes in coil sensitivity, when acquiring MR spectra with a receive-only head coil.     

Mucociliary transport using 99mTc-albumin colloid: a reliable screening test for primary ciliary dyskinesia

BACKGROUND: A study was undertaken to assess the reliability of the nasal mucociliary transport test using 99mTc-albumin colloid as a screening test for primary ciliary dyskinesia (PCD) and to compare it with the gold standard nasal biopsy for study of ciliary motility and ultrastructure. METHODS: During a 4 year period both tests were performed in 55 children referred with persistent or recurrent respiratory tract infections. Their median age was 4 years (range 1 month to 15 years). RESULTS: The nasal biopsy results were as follows: PCD, n = 8; secondary ciliary dyskinesia (SCD), n = 19; normal, n = 28. The mucociliary transport test was abnormal in 29 patients (all 8 with PCD, 7/19 with SCD, and 14/28 with a normal biopsy). The sensitivity of the mucociliary transport test to diagnose PCD was therefore 100% (8/8) (95% exact confidence limits 63.06 to 100.00); the specificity was only 55% (26/47) (40.95 to 69.89). The negative predictive value was 100% (26/26) (86.77 to 100.00) and the positive predictive value was 28% (8/29) (12.37 to 47.24). CONCLUSION: Mucociliary transport is a non-invasive screening test that can be performed even in infants. The sensitivity of the test is high but its specificity is low. A normal test result excludes PCD.     

Multidrug-resistant tuberculosis detection, Latvia

To improve multidrug-resistant tuberculosis (MDR-TB) detection, we successfully introduced the rpoB gene mutation line probe assay into the national laboratory in Latvia, a country with epidemic MDR-TB. The assay detected rifampin resistance with 91% sensitivity and 96% specificity within 1 to 5 days (vs. 12-47 days for BACTEC).