abstract id : iria - 1198. 30 yr old female came with c/o chest pain, shortness of breath,...
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VASCULAR CAUSES OF ABSENT/SMALL HILUM – 64 SLICE CT
ABSTRACT ID : IRIA - 1198
30 yr old female came with
c/o chest pain,
shortness of breath,
recurrent respiratory tract infections,
anasarca,
CXR:Small right hemithorax with hyperlucency noted,Displacement of the mediastinum, to right sideAbsent hilar shadow and paucity of vascular markings on right lung field ,Prominence of left hilum with pulmonary plethoraCystic lucencies noted in b/l lower zonehyperinflation of the left lung.
CT CHEST PLAIN
Right lung shows volume loss with mediastinal shift to right sideCystic bronchiectatic changes noted on right side
CT PULMONARY ANGIOGRAM
Enlarged main pulmonarey artery (3.8cm) and left pulmonary artery(2.4cm),Absent right pulmonary arteryDecreased pulmonary vasculature noted on right sidePulmonary plethora on the left side.
Prominence of the left pulmonary artery branchesThe right pleural surface appears beaded because of the presence of prominent intercostal arteries serving as collateral vessels.
Reconstructed ,VR images Patent ductus arteriosusProminent main pulmonary artery,Left pulmonary artery
DIAGNOSIS
UNILATERAL ABSENCE OF PULMONARY ARTERY (Right pulmonary artery
agenesis)
Associated with
Pulmonary hypertension
Patent ductus arteriosus
UNILATERAL ABSENCE OF PULMONARY ARTERY
UAPA is estimated to be around 1 in 200,000 individuals The main embryologic defect is an involution of the proximal sixth aortic arch of the
affected side, leading to an absence of the proximal pulmonary artery. Intrapulmonary vessels and distal portion of the affected pulmonary artery trunk can
develop normally, and blood supply is achieved by systemic collaterals from bronchial, major aortopulmonary collaterals and other systemic arteries
UAPA is twice as common on the right side
Symptoms- Due to large systemic - pulmonary collaterals from
bronchial,intercostal,internalmammary arteries. Hemoptysis – 10% due to rupture of these hypertrophied collaterals. Recurrent chest infections Pulmonary hypertension - >40yrs.
Left-sided agenesis seems to be more frequently associated with cardiac abnormalities such as tetralogy of Fallot, septal defects, patent ductus arteriosus, coarctation of the aorta and transposition of great vessels and therefore early diagnosis and surgical repair are required during the first year of life.
Patients with isolated right UAPA survive into adulthood with minimal symptoms,
making the diagnosis of such cases more difficult.
UNILATERAL ABSENCE OF PULMONARY ARTERY
The radiologic features Small hemithorax, Ipsilateral displacement of the mediastinum, Absence of the corresponding pulmonary artery, Reticular densities along the pleura and within the lung, - due to systemic collateral
circulation. Ipsilateral hemidiaphragm elevation with volume loss of the affected lung, Absent hilar shadow, hyperinflation of the contralateral lung.
CAUSES OF UNILATERAL HYPERLUCENT HEMITHORAX
Patient positioning Rotation Scoliosis
Chest wall defect Mastectomy Poland syndrome (absent pectoralis muscle)
Pneumothorax C/L Pleural effusion Airway obstruction
Bronchial compression (hilar mass, cardiomegaly) Endobronchial obstruction with air trapping (foreign body, tumor) Obliterative bronchiolitis Swyer-James syndrome Pulmonary emphysema (asymmetric) Congenital lobar emphysema Pneumatocele
Pulmonary vascular cause Pulmonary embolism Pulmonary artery hypoplasia
CT – IN UAPA
lack of an identifiable pulmonary artery. enlarged intercostal arteries serving as collateral vessels to the lung marked volume loss in the lung. The pleural surface appears beaded because of the presence of prominent intercostal
arteries serving as collateral vessels. presence of smaller than usual branches of the inferior pulmonary vein compared with
the normal-sized other side inferior pulmonary vein. Pulmonary plethora on the other side. High resolution CT scanning can evaluate the presence of bronchiectasis in cases of
recurrent bronchopulmonary infections. Pulmonary hypertension
Angiography remains the gold standard for the diagnosis of pulmonary artery agenesis.
With the development of CT, MRI and magnetic resonance angiographic techniques –it is rarely performed unless embolization is indicated for massive hemoptysis.
DIFFERENTIAL DIAGNOSIS
Swyer-James-MacLead (SJM) syndrome should be considered in the differential diagnosis of pulmonary artery agenesis.
Perfusion scintigraphy or pulmonary angiography can be used for the differentiation. The pulmonary artery is hypoplastic in patients with SJM syndrome, air trapping in
expiration and ipsilateral lung perfusion is absent. On the other hand,pulmonary artery can not be observed in patients with UAPA, but
peripherally perfusion can be seen via collaterals.
COMPANION CASE
13 year old boy Cough Mild dyspnea h/o ?near drowning Pulmonary infection in early childhood
Increased lucency on left sideSmall hilum on left side compared to right
INSPIRATION
EXPIRATION – Increased lucency on left side due to Air trapping with mild mediastinal shift to right
CT ANGIOGRAM
Hyperlucenct lung(Left) Air trapping on expiration Left small hilum Diminished Left side pulmonary vascularity Normal lung volume h/o insult to bronchial tree Ruling out other conditions of diffuse air trapping
VOLUME RENDERED AND CORONAL RECONSTRUCTION - shows small left pulmonary artery.
SWYER JAMES/ MACLEOD SYNDROME
(UNILATERAL EMPHYSEMA,UNILATERAL LOBAR EMPHYSEMA,UNILATERAL HYPERLUCENT LUNG)
• Swyer-James syndrome (McLeod syndrome) • unilateral post infectious bronchiolitis obliterans in infancy and early childhood. • presence of concentric fibrosis involving the submucosal and peribronchial tissues of
terminal and respiratory bronchioles ,resulting in bronchial narrowing or obliteration
Radiological features… Nonspecific Large lung volume Small hilum Increased lung lucency(60%) Reduced size of peripheral vessels Central bronchiectasis HRCT – decreased lung attenuation -- decreased vessel caliber -- air trapping -- bronchiectasis / atelectasis
TAKE HOME MESSAGE…
Small hemithorax, Ipsilateral displacement of the mediastinum, Absence of the corresponding pulmonary artery, Reticular densities along the pleura and within the lung, - due to systemic collateral circulation,Absent hilar shadow, hyperinflation of the contralateral lung.
UNILATERAL ABSENCE OF PULMONARY ARTERY
Unilateral hyperlucency with evidence of air trapping,reduced size of pulmonary vessels,small hilum,bronchiectasis and history of some insult to the bronchial tree during early childhood
SWYER JAMES SYNDROME