British Journal of Radiology (2007) 80, e61-e63
© 2007 British Institute of Radiology
doi: 10.1259/bjr/94062779
CT findings of pulmonary artery dissection
M A Neimatallah, MD1,
W Hassan, MD, FCCP, FACC, FACP2,
M Moursi, MD2 and
Y Al Kadhi, MD1
Departments of 1 Radiology and 2 Cardiology, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
Correspondence: Mohammed A Neimatallah, Department of Radiology, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh 11211, Kingdom of Saudi Arabia. E-mail: neimatal{at}yahoo.com.
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Abstract
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Pulmonary artery dissection is a serious fatal complication of chronic pulmonary arterial hypertension, always occurring at the site of maximal dilatation of the artery [1]. Diagnosis is made mainly at autopsy as many of these patients experience sudden death when the main pulmonary artery dissects into the pericardium, causing acute cardiac tamponade. To our knowledge, five reported cases have described CT imaging findings of acute pulmonary artery dissection in the literature.
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Case report
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A 44-year-old man, known to have pulmonary hypertension, presented to the emergency department with a 3 day history of constricting central chest pain. Physical examination revealed a regular pulse rate 65 beats min–1, and a blood pressure of 139/70 mmHg. Jugular venous pressure was 8 cm, cardiac auscultation revealed a loud pulmonary component of the second heart sound with parasternal lift and heave. The lungs were clear. ECG showed normal sinus rhythm with biventricular hypertrophy. Cardiac enzymes and tropin levels were normal. Chest X-ray revealed moderate cardiomegaly with an enlarged pulmonary trunk and pulmonary vessels. The lungs and pleura were normal (Figure 1
). Echocardiogram revealed normal left ventricular systolic function with moderate hypertrophy, a dilated and severely hypertrophied right ventricle with impaired function, moderate bi-atrial enlargement, and a dilated main pulmonary artery (65 mm) with the suspicion of a dissection flap near a patent ductus arteriosus that demonstrated bi-directional flow (Figure 2). Systolic pulmonary artery pressure was 140 mmHg (mean of 100 mmHg) with mild tricuspid and pulmonary regurgitation. A contrast-enhanced CT scan of the chest was performed to confirm the diagnosis using the following parameters, 3 mm scan thickness, a pitch of 1.7 and 120 ml of intravenous Omnipaque (Schering, Berlin, Germany) using a power injector at a flow rate of 5 ml s–1 and a scan delay of 20 s. The CT scan demonstrated a moderate pericardial effusion, marked dilatation of the main pulmonary artery and central branches with pruning of the peripheral branches consistent with pulmonary hypertension in addition to an intimal dissection flap originating superior to the pulmonary valve and extending cranially for a distance of 5 cm confirming the echocardiogram findings (Figure 3). No pulmonary emboli were identified. Unfortunately, the patient suddenly collapsed and died before surgical intervention was possible.
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Figure 1. Posteroanterior chest radiograph showing cardiac enlargement with greatly dilated pulmonary trunk and central pulmonary arteries.
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Figure 2. 2D transthoracic echocardiogram in a short axis oblique view showing a greatly dilated main pulmonary artery(PA) with an intimal flap (white arrow).
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Figure 3. (a–c) Transverse section of a contrast-enhanced CT pulmonary angiogram showing dilated central pulmonary arteries with an intimal flap in the main pulmonary artery (black arrowheads, a–c) and a pericardial effusion (white arrow, b).
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Discussion
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Pulmonary artery dissection is a rare and fatal disease. It usually occurs as a complication of chronic pulmonary arterial hypertension. Other rare causes include chronic inflammation of the pulmonary arteries, right heart endocarditis, amyloidosis, trauma and severe atherosclerosis [2]. It should be considered in patients with pulmonary hypertension who present with cardiogenic shock, collapse or sudden cardiac death [3]. Signs and symptoms include dyspnoea occurring in 82%, chest pain in 67% and central cyanosis in 52% [1]. Pulmonary dissection always occurs at the site of maximal dilatation of the artery and is firmly related to degeneration of the media. Unlike aortic dissection, the false lumen in pulmonary artery dissection tends to rupture rather than to develop a re-entry site [1]. Diagnosis is made mainly at autopsy as many of these patients experience sudden death when the main pulmonary artery dissects into the pericardium, causing acute cardiac tamponade. Senbaklavaci et al reported surgical treatment of pulmonary artery dissection using T-shaped prosthetic graft replacement of the central pulmonary artery as emergency surgery to prevent lethal bleeding [4].
Non-invasive imaging methods used to detect pulmonary artery dissection in living patients are transthoracic echocardiogram [5, 6], CT scanning [2], MRI [7] and pulmonary arteriography [8]. Echocardiography is used more often as a first line of investigation because of its accessibility and low cost; CT particularly multidetector CT may be used if echocardiography fails to detect an intimal flap. It may also be used to provide complementary information related to the extent of dissection. It may be used as a first line of investigation if pulmonary embolism is the suspected diagnosis [9, 10]. Multidetector CT has many advantages over other modalities including fast volume coverage as well as isotropic resolution that allows multiplanar reformation and 3D rendering capable of accurately displaying the intimal flap, extent of the dissection and intraluminal thrombi. It can also demonstrate haemopericardium secondary to pulmonary artery dissection into the pericardium causing acute cardiac tamponade. In addition CT can accurately evaluate the diameter and extent of the aneurysm and can exclude the presence of pulmonary embolism. Accurate bolus timing is possible nowadays with new scanners using automated bolus detection.
In conclusion, contrast-enhanced CT pulmonary angiography is a useful modality to diagnose pulmonary artery dissection in patients with chronic pulmonary arterial hypertension presenting with acute severe chest pain, dyspnoea on exertion, central cyanosis or sudden haemodynamic decompensation as a first line of investigation or as a complement to echocardiography in the early diagnosis of such conditions. This may facilitate emergency surgical intervention to prevent lethal bleeding.
Received for publication October 11, 2005.
Revision received February 4, 2006.
Accepted for publication March 28, 2006.
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References
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- Senbaklavaci O, Kaneko Y, Bartunek A, Brunner C, Kurkciyan E, Wunderbaldinger P, et al. Rupture and dissection in pulmonary artery aneurysms: incidence, cause, and treatment--review and case report. Thorac Cardiovasc Surg 2001;121:1006–8.[CrossRef]
- Wunderbaldinger P, Bernhard C, Uffmann M, Kurkciyan I, Senbaklavaci O, Herold CJ. Acute pulmonary trunk dissection in a patient with primary pulmonary hypertension. J Comput Assist Tomogr 2000;24:92–5.[CrossRef][Medline]
- Walley VM, Virmani R, Silver MD. Pulmonary arterial dissections and ruptures: to be considered in patients with pulmonary arterial hypertension presenting with cardiogenic shock or sudden death. Pathology 1990;22:1–4.[Medline]
- Senbaklavaci O, Kaneko Y, Bartunek A. Rupture and dissection in pulmonary artery aneurysms: incidence, cause and treatment – review and case report. J Thorac Cardiovasc Surg 2001;121:1006–8.[Free Full Text]
- Tonder N, Kober L, Hassager C. Pulmonary artery dissection in a patient with Eisenmenger syndrome treated with heart and lung transplantation. Eur J Echocardiogr 2004;5:228–30.[CrossRef][Medline]
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- Steurer J, Jenni R, Medici TC, Vollrath T, Hess OM, Siegenthaler W. Dissecting aneurysm of the pulmonary artery with pulmonary hypertension. Am Rev Respir Dis 1990;142:1219–21.[Medline]
- Khattar RS, Fox DJ, Alty JE, Arora A. Pulmonary artery dissection: an emerging cardiovascular complication in surviving patients with chronic pulmonary hypertension. Heart 2005;91:142–5.[Abstract/Free Full Text]
- Song EK, Kolecki P. Case of pulmonary artery dissection diagnosed in the Emergency Department. J Emerg Med 2002;23:155–9.[CrossRef][Medline]
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Abstract
Case report
