pulmonary sequestration

Lungensequester
rechts im posterobasalen Unterlappen mit systemarteriellen Zustrom direkt aus der Aorta abdominalis und pulmonalvenösem Abfluss. Computertomografie: Links axiale und sagittale Schichten im Lungenfenster, rechts Volume-Rendering mit Darstellung des Verlaufs des systemarteriellen Zuflusses aus der infradiaphragmalen Aorta und des pulmonalvenösen Abstroms zum linken Vorhof.
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Infant with
an echogenic lung lesion on prenatal ultrasound. Gross pathological image shows a left-sided supradiaphragmatic mass separate from the left lung. There was a feeding vessel connecting it to the aorta.The diagnosis was pulmonary sequestration.
pediatricimaging.org • CC-by-nc-sa 4.0
Infant with
an echogenic left lung mass on prenatal US. CXR AP (above) shows a faint triangular opacity in the medial aspect of the left lower lobe. 3 sequential images from the arterial phase of an aortic angiogram obtained 7 months later (below) show a lesion in the medial aspect of the left lower lobe that receives its arterial blood supply from the subdiaphragmatic aorta.The diagnosis was pulmonary sequestration in the left lower lobe.
pediatricimaging.org • CC-by-nc-sa 4.0
Pictorial
review of the pulmonary vasculature: from arteries to veins. Pulmonary sequestration. a Conceptual illustration of extralobar and intralobar sequestration. Note that extralobar sequestration involves venous drainage into the azygos system forming a left-to-right shunt while intralobar sequestration involves pulmonary venous drainage forming a left-to-left shunt. b Axial CT demonstrating an asymptomatic oval lesion (white arrow) in the left lower lobe consistent with extralobar sequestration in a 23-year-old woman. Blood supply is derived from the abdominal aorta with venous drainage occurring via the azygos system. Double oblique CT MIP images (c, d) and coronal CT MPR image (e) demonstrating an intralobar sequestration located within the pleura of the left lower lobe. Note the aberrant arterial supply to the lateral left lower lobe below the level of the diaphragm (black arrows) which extends through the diaphragm into the tissues of the left lower lobe (white arrows). Venous drainage of this intralobar sequestration is via the pulmonary venous system (arrowheads)
insightsimaging.springeropen.com • CC-by-4.0
chest CT:
diagnosis is pulmonary sequestration
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Imaging of
congenital lung diseases presenting in the adulthood: a pictorial review. Different examples of pulmonary sequestrations. Axial CT images (a, b) and 3D cinematic volume-rendered reconstruction image (c) show three aberrant arteries which arise from the descending thoracic aorta and feed a consolidated area in the left lower lobe in a 25-year-old female with sequestration who presented with dyspnea (arrows). Coronal CT images (d, e) and 3D volume-rendered reconstruction (f) image demonstrate bilateral sequestrations with aberrant arteries arising from the abdominal aorta in a 22-year-old asymptomatic woman (arrows)
insightsimaging.springeropen.com • CC-by-4.0
Imaging of
congenital lung diseases presenting in the adulthood: a pictorial review. Mixed lesions-pulmonary sequestration and bronchial atresia in a 45-year-old asymptomatic female. Coronal CT image shows bronchial atresia with the finger-in-glove appearance (a, arrow). Hyperinflation of the obstructed lung area is observed on both coronal (a) and quantitative 3D reconstruction CT images (blue area) (b). Axial (c) and coronal (d) maximum intensity projection (MIP) images demonstrate pulmonary sequestration supplied from an aberrant artery arising from the right inferior phrenic artery (arrows). Bronchial atresia is also seen on the coronal MIP image (red arrow)
insightsimaging.springeropen.com • CC-by-4.0
Imaging of
congenital lung diseases presenting in the adulthood: a pictorial review. Mixed lesions-pulmonary sequestration and bronchogenic cyst in a 38-year-old male who presented with dyspnea. Contrast-enhanced axial CT images show bronchogenic cyst (a, arrow) and aberrant artery arising from the descending aorta and feeding the left lower lobe sequestration (b, arrow). Coronal CT image (c) shows both bronchial cyst and aberrant artery of sequestration (arrows). 3D volume-rendered CT image (d) shows the aberrant artery (arrow)
insightsimaging.springeropen.com • CC-by-4.0
Pulmonary
sequestration • Pulmonary sequestration (prenatal and postnatal ultrasound) - Ganzer Fall bei Radiopaedia
Patel M, Pulmonary sequestration (prenatal and postnatal ultrasound). Case study, Radiopaedia.org (Accessed on 09 Feb 2023) https://doi.org/10.53347/rID-27529 • CC by-nc-sa 3.0 (modified)
Infant with
fever and respiratory distressCXR shows a large round opacity in the left lower lobe that abuts the diaphragm. Coronal T1 MRI with contrast of the chest shows a uniformly enhancing mediastinal mass that extends into the retrocrural regions of the chest bilaterally and that has a feeding vessel arising from the aorta.The diagnosis was pulmonary sequestration (extralobar).
pediatricimaging.org • CC-by-nc-sa 4.0
Imaging of
congenital lung diseases presenting in the adulthood: a pictorial review. A 67-year-old asymptomatic male with sequestration. Contrast-enhanced axial CT image in the mediastinal window (a) and 3D volume-rendered reconstruction image (b) demonstrate the aberrant artery originating from the descending thoracic aorta (arrows). Axial CT image in the lung window (c) depicts right lower lobe opacity corresponding to the sequestration
insightsimaging.springeropen.com • CC-by-4.0
Pulmonary
sequestration • Intra-lobar pulmonary sequestration complicated by infection - Ganzer Fall bei Radiopaedia
Schubert R, Intra-lobar pulmonary sequestration complicated by infection. Case study, Radiopaedia.org (Accessed on 09 Feb 2023) https://doi.org/10.53347/rID-17630 • CC by-nc-sa 3.0 (modified)
Infant with
cough and wheezing. CXR AP (above) shows a round density projecting to the left of the 8th and 9th thoracic vertebral bodies. Axial CT without contrast of the chest (below) better shows a solid left paraspinal mass. In the operating room it was seen to lay outside the lung and to have its arterial supply coming from the aorta.The diagnosis was extralobar pulmonary sequestration.
pediatricimaging.org • CC-by-nc-sa 4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Pulmonary sequestration, also called accessory lung, refers to the aberrant formation of segmental lung tissue that has no connection with the bronchial tree or pulmonary arteries. It is a bronchopulmonary foregut malformation (BPFM).

There are two types:

Epidemiology

The estimated incidence is 0.1%. Some authors propose a greater male prevalence (this may be the case for the extralobar type) . The age of presentation is dependent on the type of sequestration (see below).

Clinical presentation

Extralobar sequestration (ELS) more commonly presents in newborns as respiratory distress, cyanosis, or infection, whereas intralobar sequestration (ILS) presents in late childhood or adolescence with recurrent pulmonary infections.

Pathology

Pulmonary sequestration can be divided into two distinct groups based on the relationship of the aberrant segmental lung tissue to the pleura:

  • intralobar sequestration (ILS)
    • accounts for the majority (75-85% of all sequestrations )
    • present later in childhood with recurrent infections
  • extralobar sequestration (ELS)
    • less common (15-25% of all sequestrations )
    • usually present in the neonatal period with respiratory distress, cyanosis, or infection
    • recognized male predilection M: F ratio ~4:1
    • can be infradiaphragmatic in ~10% of cases

The two types of sequestration are similar in their relationship to the bronchial tree and arterial supply/venous drainage but differ in their relationship to the pleura.

By definition, there is no communication with the tracheobronchial tree. In the vast majority of cases, the abnormal lung tissue has a systemic arterial supply which is usually a branch of the aorta:

  • intralobar sequestrations
  • extralobar sequestrations
    • venous drainage most commonly through the systemic veins into the right atrium (but is variable)
    • separated from any surrounding lung by its own pleura
Genetics

Almost all cases occur sporadically.

Location

Overall, sequestration preferentially affects the lower lobes. 60% of intralobar sequestrations affect the left lower lobe, and 40% the right lower lobe. Extralobar sequestrations almost always affect the left lower lobe, however, ~10% of extralobar sequestrations can be subdiaphragmatic .

Associations

Associated disease is common with the extralobar type (50-60%):

Radiographic features

Plain radiograph
  • often show a triangular opacity in the affected segment
  • may show cystic spaces if infected
  • both ILS and ELS can rarely have air bronchograms as they may acquire a connection to the bronchial tree due to an infective process or, rarely, they can have foregut communication (esophagus or stomach) as part of hybrid lesion
Ultrasound

The sequestrated portion of the lung is usually more echogenic than the rest of the lung. On antenatal ultrasound, an extralobar sequestration may be seen as early as 16 weeks gestation and typically appears as a solid well-defined triangular echogenic mass . Color Doppler may identify a feeding vessel (in-utero cases) from the aorta. If the sequestration is subdiaphragmatic, it may appear as an echogenic intra-abdominal mass.

CT
  • cross-sectional imaging frequently demonstrates the arterial supply by the descending aorta
  • they may arise below the diaphragm in 20% of patients
  • usually does not contain air unless infected
  • 3D reconstructions can be particularly helpful in detecting
    • anomalous arterial vessels
    • concurrent anomalous veins 
    • differentiating between intralobar and extralobar sequestrations
Angiography (DSA)

Not part of the routine investigation but is the gold standard in determining arterial supply.

MRI
  • T1: the sequestrated segment tends to be of comparatively high signal to normal lung tissue
  • T2: also tends to be of comparatively high signal
  • MRA: can be helpful in demonstrating anomalous arterial supply

Treatment and prognosis

Traditionally treatment has been surgical resection. Extralobar sequestrations with their separate pleural investments can usually be removed sparing normal lung tissue, although, with an intralobar type, segmental resection or even lobectomy will be necessary.

Coil embolization has also been successfully trialed in selected cases . Spontaneous involution has been reported in occasional cases .

Complications

Differential diagnosis

General imaging differential considerations include:

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Lungensequester:
Bronchogene
Zyste
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Scimitar-Syndrom
 
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arteriovenöse
Malformationen der Lunge
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bronchopulmonale
Vordarmmalformation
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kongenitale
Zwerchfellhernie
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