39CT with thickened airway walls, debris within the airway, and sparse peribronchial
consolidation or small centrilobular nodules [ 1 ]. Chest CT has utility in identifying
CMV pneumonia which is generally bilateral with poorly defined nodules and patchy,
diffuse ground-glass attenuation. Paranasal sinusitis is a complication in which CT
imaging is very helpful and is even advocated by some to be used as a screening tool.
Usually, air-fluid levels and soft-tissue thickening are present on CT imaging
(Fig. 3.2). Direct coronal CT is the preferred imaging technique as it is more sensitive
for detecting the more understated changes that could be of significant importance in
the management of this disease. This is very important in the case of invasive fungal
sinusitis as it is generally rapidly progressive and can have dire consequences [ 2 ].
Later complications include bronchiolitis obliterans and cryptogenic organizing
pneumonia. Bronchiolitis obliterans is a unique long-term complication after allo-
geneic stem cell transplantation; plain radiographs may show some abnormalities,
but children can have severe nonreversible obstructive abnormalities detected by
pulmonary function testing, when the chest X-ray may be interpreted as near-
normal. Chest CT is of a higher diagnostic yield and may show a mosaic pattern
(where parenchymal lucencies are seen adjacent to normal lung), expiratory air
trapping, as well as, bronchial dilation and bronchial wall thickening (Fig. 3.3) [ 1 ].
Cryptogenic organizing pneumonia would be seen as sparse peripheral infiltrates,
usually peribronchial or subpleural on chest CT, with restrictive pattern seen on the
pulmonary function tests [ 3 ].
Fig. 3.2 Zygomycetes sinusitis 1 year post-transplant. Axial CT image through the maxillary
antra demonstrate bilateral mucosal thickening with high attenuation material within the opacified
left maxillary antrum, suggesting fungal infection
3 Radiologic Procedures Used in Pediatric Stem Cell Transplantation