Figure 1
Thoracic CT after intravenous administration of contrast
Clinical History
Pneumonia, productive cough and fever
Imaging Findings
A 49 year old male, smoker since 15 years of age, with history of chronic pneumonia, productive cough and fever. The patient obtained benefits from the antibiotic therapy with substantial reduction of severity of symptoms. Recently he had a single episode of fever (37,5°C) associated with non productive cough. Chest CT was performed and revealed a parenchymal consolidation in the right lower lobe.The nature of this consolidation was better characterized by MR imaging and Angiography, that confirmed an intralobar sequestration.
Discussion
Pulmonary sequestration has been classically described in two forms: intralobar and extralobar sequestration. Intralobar sequestration has been suggested by several authors to be a congenital malformation consisting of non functional embryonic lung tissue lying within normal pulmonary visceral pleura, with no communication with normal bronchial system, supplied by aberrant systemic artery.The arterial supply is usually from the descending thoracic aorta (73%)but occasionally by upper abdominal aorta, celiac or splenic arteries (21%)(3). In decreasing order of frequency the intercostal, subclavian,internal thoracic may be supplying arteries(5). The venous drainage is provided by pulmonary veins.The intralobar sequestration is located in lower lobes (98%), occurring on the left side in the majority of cases (58%). Extralobar sequestration is characterized by the complete separation of the embryonic tissue that is enclosed in its own pleural investment and it presents a greater left side preponderance (over 80%).The venous drainage of extralobar sequestration is usually systemic (80% of cases)through the azygos and hemiazygos system or superior vena cava in the right atrium. Clinical manifestations consist of chronic and recurrent pneumonia, productive cough, fever and haemoptysis. In presence of a large systemic arterial venous shunt, the patients may have exercise intolerance. This anomaly is rarely detected in infancy (usually associated with other anomalies). The diagnosis of pulmonary sequestration traditionally requires arteriography (1)to identify abnormal systemic vessels feeding the abnormal portion of the lung. CT and MRI are useful for locating sequestered parenchyma and large vascular supply (2), while angiography can delineate small arterial supplying vessels. Recent advances in MR angiography (4)based on to multiplanar imaging suggest the capability of this technique to recognize small vessels and also multi row detector CT permits the demonstration of both arterial supply from the descending aorta and venous drainage to hemiazygos vein.Therefore actually angiography remains an essential tool in the diagnosis of pulmonary sequestration, notwithstanding the great potentials of multi row detector CT and MR angiography. Differential diagnosis includes bronchiectasis, lung abscess, artero-venous shunt in Rendu-Osler-Weber disease, and Bochdalek hernia.
Differential Diagnosis List
Intralobar sequestration
Final Diagnosis
Intralobar sequestration
References
[1] Ettorre GC, et al. Pulmonary sequestration in the adult. Diagnostic contribution of angiography. Radiol Med. 2000; 99 (1-2): 41-5. (PMID: 10803185)
[2] Di Maggio E.M. et al. Spiral CT findings in a case of pulomary sequestration. Eur Radiol 1997;7(5):718-20. (PMID: 9166571)
[3] Felker R.E. et al. Imaging of pulomonary sequestration. AJR 1990;154(2):241-9. (PMID: 2105007)
[4] Au VW. et al. Pulomonary sequestration diagnosed by contrast enhanced three-dimensional MR angiography. Br J Radiol 1999;72(859):709-11. (PMID: 10624331)
[5] Bertsch G. et al. Intralobar lung sequestration with systemic coronary artery supply. Eur Radiol 1999;9(7):1324-6. (PMID: 10460367)
Case information
| URL: | https://www.eurorad.org/case/617 |
| DOI: | 10.1594/EURORAD/CASE.617 |
| ISSN: | 1563-4086 |
