Intra-lobar pulmonary sequestrations. Value of computed tomography and MRI in nine cases with typical and borderline appearances

The authors report 9 cases of intralobar pulmonary sequestrations (ILS) investigated by means of 9 computed tomography (CT) scans and two magnetic resonance imaging (MRI) scans. With CT: single or multiple air-filled cystic lesions with thick walls, or full cysts or even presenting a fluid level, co-existed in at least 8 out of 9 cases with images of parenchymal rarefaction due to the presence of foetal parenchyma in the sequestrum. The margins between the sequestrum and the adjacent parenchyma were clearly defined. There were no signs of bronchiectasis and the topography of the lesions could be easily identified. A vascular anomaly was most frequently suspected, but the vascular pedicle was not always visualized. Computed tomography should be the first investigation performed after plain chest X-rays. Unless the vascular pedicle can be demonstrated on CT, arteriography is still essential, but it may possibly be replaced by MRI. However, at the present time, MRI is unable to replace the CT scan which provides an excellent study of the parenchyma and the bronchi, even if MRI has the advantage of a signal study of solid cystic lesions with a suggestive intense T1 and T2 signal, reflecting a high intracystic protein concentration. The classification and anatomical difficulties argue in favour of a complete diagnostic assessment