Medical Image of the Week: Acute Aortic Dissection

Figure 1. Acute aortic dissection presenting with the following radiographic signs: rightward deviation of the trachea (red arrow); left apical pleural capping (blue arrow); aortic “double-calcium” sign (between white arrows); depression of the left bronchus (purple arrow); pleural effusion (green arrow); widened mediastinum and loss of the aorto-pulmonary window (not labeled).

The patient was a 75 year old woman with a past medical history of uncontrolled hypertension and recent type-A aortic dissection post graft repair. She presented with a sudden onset of sharp mid-back pain which awoke her from sleep. In the emergency room a chest x-ray revealed numerous features consistent with a de novo type B aortic dissection which was ultimately confirmed by magnetic resonance angiography of the chest and abdomen. This dissection extended from the left subclavian artery to the right renal artery. There was no evidence of end-organ mal-perfusion and the patient was medically managed by way of blood pressure control.

Seth Assar, MD; Thien Vo, MD; Jarrod Mosier, MD

The University of Arizona College of Medicine, Tucson, Arizona

Reference

Bansal V, Lee J, Coimbra R. Current diagnosis and management of blunt traumatic rupture of the thoracic aorta. J Vasc Bras. 2007;6(1):64-7. [CrossRef]

Reference as: Assar S, Vo T, Mosier J. Medical image of the week: acute aortic dissection. Southwest J Pulm Crit Care. 2014;8(4):234. doi: http://dx.doi.org/10.13175/swjpcc039-14 PDF

Medical Image of the Week: Pulmonary Arteriovenous Fistula

Figure 1. Panel A: Micro-bubbles appear in the right atrium (RA) and right ventricle (RV) with delayed appearance in the left atrium (LA) and left ventricle (LV). Panels B and C: The density of the micro-bubbles were same in the left and the right cardiac chambers even after 10 cardiac cycles. Panel D: When the injection was stopped, there were micro-bubbles in the left cardiac chambers, but none in the right cardiac chambers.

A 60 year-old man with hepatic cirrhosis, was referred for chest pain, shortness of breath, and progressive cyanosis and an echocardiographic evaluation. PaO2 was 64 mm Hg on room air, but only 74 mm Hg on 100% oxygen.  Chest X-ray and pulmonary function testing were normal. A contrast echocardiography using agitated saline (bubble study) was performed. A delayed appearance of a substantial amount of micro-bubbles in the left atrium greater than three cardiac cycles after appearance in the right atrium and ventricle was suggestive of pulmonary arteriovenous fistula (Figure 1A). The delayed appearance and a large amount of micro-bubbles in the left atrium preclude the intracardiac shunting result of a patent foramen ovale (PFO) or atrial septal defect (ASD). Interestingly, the density of micro-bubbles were same in the left and the right cardiac chambers even after 10 cardiac cycles (Figure 1B and 1C). When the injection was stopped, there were micro-bubbles in the left cardiac chambers, but none in the right cardiac chambers (Figure 1D). Although pulmonary angiography remains the gold standard method for definitive diagnosis of the pulmonary arteriovenous malformations, contrast echocardiography can suggest arteriovenous fistula in the setting of unexplained hypoxemia before angiography, especially in hospitals without on-site angiography facilities.

Manisha Bajracharya MD, Madhu Gupta MD, Liping Chen MD PhD

Department of Gynecology and the Cardiovascular Disease Center, Norman Bethune College of Medicine, Jilin University, Changchun, China

Reference

Nanthakumar K, Graham AT, Robinson TI, Grande P, Pugash RA, Clarke JA, Hutchison SJ, Mandzia JL, Hyland RH, Faughnan ME. Contrast echocardiography for detection of pulmonary arteriovenous malformations. Am Heart J. 2001;141(2):243-6. [CrossRef] [PubMed]

Reference as: Bajracharya M, Gupta M, Chen L. Medical image of the week: pulmonary arteriovenous fistula. Southwest J Pulm Crit Care. 2014;8(4): . doi: http://dx.doi.org/10.13175/swjpcc035-14 PDF