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The scanner, or computed tomography, is the reference imaging test for most thoracic diseases in both adults and children. It has gone through tremendously rapid technological progress over the last few years with the appearance of multirow (or multidetector or multislice) scanners. This technology currently provides volume acquisition of a child's thorax in 2-5 s. These technological advances are particularly useful for exploring airway diseases, largely because of the range of reconstruction possibilities (maximum and minimum intensity projection, volume rendering, virtual endoscopy), which offer advantageous perspectives in pediatrics. Multiplanar imaging and above all three-dimensional imaging provide a totally original analysis in space of the sometimes complex relations between vascular and airway structures, making it possible to understand certain extrinsic bronchial compression mechanisms more precisely. The present study briefly reviews the technical aspects of the thoracic scanner in children and illustrates its role today in volume CT in childhood thoracic diseases using clinical examples taken from our daily practice.

Have been selected for this review: 1) the recent and impressive development of high-resolution and spiral CT scan in pediatric thoracic imaging; 2) the emerging of new and promising therapies for asthma (long acting inhaled beta 2-agonists, leukotriene antagonists, anti-IgE monoclonal antibodies); 3) the multifactorial origin of asthma in childhood; 4) the development of thoracoscopic surgery, a minimal-invasive approach beneficial in numerous circumstances.

This article presents an exhaustive review of MRI in the assessment of the pulmonary arteries (sequences, normal results, clinical signs of the main diseases). Its current preferential indications are: the study of the main pulmonary artery trunks (primary tumours, proximal embolism, caliber abnormalities, anatomical relations with central tumours), the assessment and post-treatment follow-up of pulmonary arterial malformations. Angio-MRI is currently being developed and, in the near future, should allow the reliable diagnosis of pulmonary embolism and will therefore be indicated alongside spiral computed tomography. MRI also allows functional assessment of the right circulation (measurements of circulatory velocity and flow rates). It should rapidly become an examination of choice in the haemodynamic follow-up of patient with pulmonary hypertension and transplant recipients and as an evaluation tool for new drugs.

This analysis of 31 cases of anomalies of the aortic arch has confirmed the predominance of subclavian retro-oesophageal arteries and double aortic arches (74% of cases). The age at which the first clinical signs presented was less than one year in 75% of cases. Respiratory signs predominated with recurrent bronchitis (16 cases) and bronchial congestion (9 cases). These signs were not specific for the type of aetiology and were characterised by their chronicity and recurrent nature. Inspiratory and expiratory stridor was found on 8 occasions and was very suggestive of the diagnosis. There was a frequent association of asthma and anomalies of the aortic arch in this series (13 cases) with 6 cases of atopic asthma in early childhood and 7 cases of asthma in infancy. The oesophago-gastroduodenal transit was the key diagnosis which enabled the vascular anomaly to be confirmed. There was, however, a failure on 5 occasions with 2 false negatives and 3 cases where the wrong type was suspected. Fibreoptic bronchoscopy enabled the topography to be established more precisely including the degree of compression (in 14 cases) and showed evidence of associated tracheomalacia in 7 cases. Nuclear magnetic resonance was very helpful, giving a better definition of the anatomical type and of the relationship of the vascular arch with the oesophago-tracheal axis. Broncho-fibroscopy and nuclear magnetic resonance make strong contributions towards the indications for operation.

A prospective study by nuclear magnetic resonance in 7 infants with respiratory disorders and with a barium swallow suggestive of anomalies of the aortic arch was conducted. It allowed the definition of an investigation protocol including sedation, RF coil adapted to infants size, naso-gastric tube placement, thin MR sections. Sequences are T1 weighted with ECG gating in two perpendicular frontal oblique and transverse oblique planes determined on a scout sagittal MR acquisition. Precise determination of the anatomy of the vascular malformation and its relationship with the trachea and esophagus were obtained. After definition of the investigation protocol, MRI was found to be a very effective evaluation technique for aortic arch anomalies. It can be proposed as an alternative to preoperative digital angiography. Its indications remain to be defined in relation to the clinical features and the results of the chest X-ray and barium swallow.