Idiopathic pulmonary fibrosis complicated by acute thromboembolic disease: chest X-ray, HRCT and multi-detector row CT angiographic findings

Abstract

Idiopathic pulmonary fibrosis (IPF) is a chronic diffuse interstitial disease characterized by a predominant reticular pattern of involvement of the lung parenchyma which can be well documented by High Resolution Computed Tomography (HRCT). While almost half of the patients with IPF may develop pulmonary arterial hypertension, the occurrence of superimposed acute thrombo-embolic disease is rare.We describe a case of an 87 yrs old female who was found to have IPF complicated by acute pulmonary thrombo-embolism during the clinical and radiological investigation of a rapidly worsening dyspnea. While chest x-ray findings were initially considered consistent with a congestive heart failure, a bed side echocardiography revealed findings suggestive of pulmonary arterial hypertension and right ventricular failure with enlargement of both right cavities and associated valvular regurgitations. An acute thrombo-embolic disease was initially ruled out by a perfusion lung scintigraphy and subsequently confirmed by contrast-enhanced multi-detector CT which showed an embolus at the emergency of the right inter-lobar artery with associated signs of chronic pulmonary hypertension. However, unenhanced scans performed with both conventional and high resolution techniques also depicted a reticular pattern of involvement of lung parenchyma considered suggestive of IPF despite a atypical upper lobe predominance. IPF was later confirmed by further clinical, serological and instrumental follow-up.

Keywords: Idiopathic pulmonary fibrosis; high resolution computed tomography; multidetector row CT angiography; pulmonary thrombo-embolism.

Figure 1

Antero-posterior chest-x-ray in a 87 yrs-old female with acute dyspnea. Linear and air-space opacities are respectively depicted in the whole the left lung and in the right upper lobe with associated cardiomegaly. These findings were prospectively thought to be consistent with a congestive heart failure. Retrospectively, the hyperlucency of the right lower lobe (asterisk) along with the enlargement of the inter-lobar artery represent the Westmark’s sign, highly predictive of pulmonary embolic disease.

Figure 2

Multidetector Computed Tomography performed with both conventional (A) and High Resolution (B) techniques. Axial images at the level of the aortic arch are shown. In (A) multiple reticular densities can be appreciated in both upper lobes mixed with focal areas of ground-glass attenuation. These were mostly evident in the right upper lobe and best depicted by HRCT (B) along with thickening and distortion of the inter-lobular septa. CT findings were considered consistent with Idiopathic Pulmonary Fibrosis despite the atypical upper lobe predominance.

Figure 3

Unenhanced and contrast-enhanced MDCT. Coronal Reformatted (A) and 20 mm thick Maximum Intensity Projection (B) images are shown. In (A) a predominantly reticular pattern with an upper lobe predominance is depicted. In (B) an embolus at the emergency of the lower branch of the right pulmonary artery is shown along with marked ectasia of both pulmonary arteries as a result of pulmonary arterial hypertension.