Radiological Category Thoracic Chest Principal Modality 1 General

Radiological Category: Thoracic Chest Principal Modality (1): General Radiography Principal Modality (2): CT Case Report #0449 Submitted by: Kim Learned, M. D. Faculty reviewer: Sandra A. Oldham, M. D. Date accepted: 05 January 2008

Case History 50 year-old woman presents to emergency room with shortness of breath.

Radiological Presentations PA chest radiograph

Radiological Presentations Lateral Chest Radiograph

Radiological Presentations Axial Contrast-enhanced CT Chest, soft tissue window

Radiological Presentations Axial Contrast-enhanced CT Chest, lung window

Coronal Contrast-enhanced CT Chest, soft tissue window

Radiological Presentations Coronal Contrast-enhanced CT Chest, soft tissue window

Sagittal Contrast-enhanced CT Chest, soft tissue window (correlateral view)

Radiological Presentations Coronal Contrast-enhanced CT Chest, lung window (correlate PA view)

Test Your Diagnosis Which one of the following is your choice for the appropriate diagnosis? After your selection, go to next page. • Collapsed left lung • Unilateral absence of left pulmonary artery (UAPA) • Chronic left pulmonary embolus • Chronic infection of the left lung

Findings Ipsilateral mediastinal and cardiac displacement Elevation of hemidiaphragm Small hemithorax Absent pulmonary artery shadow, absent or diminished pulmonary vascular markings Contralateral lung hyperinflation and herniation beyond the midline Loculated left pneumothorax Small hypoplastic left main bronchus

Findings Ipsilateral mediastinal and cardiac displacement Contralateral lung hyperinflation and herniation beyond the midline Bronchiectasis Hypoplastic lung with lack of Patent hypoplastic left main bronchus alveolar aeration Loculated pneumothorax

Findings Small and abruptly terminated left pulmonary artery Left superior pulmonary vein Elevation of left hemidiaphragm Contralateral lung hyperinflation and herniation beyond the midline

Findings Single right pulmonary artery Enlarged main pulmonary artery Prominent collateral intercostal arteries Prominent collateral bronchial arteries

Findings Left Superior pulmonary vein Left Atrium Left Inferior pulmonary vein

Differentials • Unilateral absence of pulmonary artery (UAPA) • Chronic pulmonary embolus

Discussion • • 2 main categories of congenital unilateral pulmonary hypoplasia: – Conditions that limit the thoracic space for normal development of the lung • Congenital diaphragmatic hernia, CCAM, Sequestration – Primary embryologic abnormal development of the lung and bronchovascular structures • Simple hypoplasia of the lung • Unilateral absence of pulmonary artery (UAPA) – Some association with congenital heart defect and vascular anomalies There are case reports in the literature of chronic pulmonary emboli indistinguishable from UAPA. History and clinical diagnosis of deep vein thrombosis and prior imaging comparison are valuable in diagnosis.

Discussion • Clinical presentation of UAPA : – If there is severe associated congenital cardiovascular anomalies or pulmonary arterial hypertension, patient becomes symptomatic earlier during childhood. – When there is UAPA with or without minor cardiovascular anomalies, patient presents later into adulthood: • Imaging abnormalities are more impressive than the asymptomatic or relatively benign nonspecific clinical history of the adult patient • Recurrent respiratory infections (37%, which is postulated from bronchoconstriction from alveolar hypocapnea, impaired mucocilliary clearance and defective delivery of inflammatory cells) • Dyspnea on exertion • Hemoptysis (20%, as a result of excessive collateral circulation) • Pulmonary arterial hypertension (20 -25%)

Diagnosis Unilateral absence of the left pulmonary artery and left pulmonary hypoplasia.

References Currarino G, Williams B. Causes of congenital unilateral pulmonary hypoplasia: a study of 33 cases. Pediatric Radiology 1985; 15: 15 -24 Moser KM, et al. Chronic thromboembolic occlusion in the adult can mimic pulmonary artery agenesis. Chest 1989; 95: 503 -508 Bouros D, et al. The varied manifestation of pulmonary artery agenesis in adulthood. Chest 1995; 108: 670 -676 Harkel D, et al. Isolated unilateral absence of a pulmonary artery: a case report and review of the literature. Chest 2002; 122: 1471 -1477