PICTORIAL REVIEW Non-invasive imaging of aberrant right subclavian artery pathologies and aberrant right vertebral artery 1 M KARCAALTINCABA, MD, 1 M HALILOGLU, MD, 1 E OZKAN, MD, 2 M KOCAK, MD, 1 D AKINCI, MD and 1 M ARIYUREK, MD 1 Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey and 2 Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA ABSTRACT. Here, we review the CT and MR angiography findings of aberrant right subclavian and right vertebral arteries, with emphasis on the differences between these structures. In addition, non-invasive imaging findings of aberrant right subclavian artery pathologies, including arteritis, aneurysm and dissection, are discussed. Received: 13 April 2006 Revised: 8 October 2006 Accepted: 15 November 2006 DOI: 10.1259/bjr/44929969 ’ 2009 The British Institute of Radiology Recent developments in non-invasive CT and MR angiographic imaging allow the diagnosis of aortic arch anomalies and the visualization of pathological findings of anomalous arteries. Imaging features of these anomalies and the spectrum of their pathologies should be known so that a confident diagnosis can be given. The combination of three-dimensional and axial images may provide better understanding of the vascular anatomy compared with conventional angiography. Aberrant right subclavian artery (ARSA) is the most common aortic arch anomaly, with an incidence of 1–2% [1, 2]. Although aneurysm and dissection of the ARSA has been described in the literature, arteritis of this anomaly is first described here [1–5]. Aberrant right vertebral artery is an extremely rare anomaly and may mimic an ARSA by its retro-oesophageal course [6]. Non-invasive angiography using multidetector CT and MRI has now become a routine application [7, 8]. The advantages of multidetector CT angiography are ease of application, wider use of the technique and simultaneous visualization of adjacent anatomic structures. MR angio- graphy provides high-quality multiphasic imaging with- out the risk of increased radiation dose, which is a significant problem with CT angiography. The aim of this pictorial review is to demonstrate non-invasive MR and CT angiographic findings from patients with normal and pathological aberrant right subclavian arteries (aneurysm and arteritis) and an aberrant right vertebral artery. Embryology and anatomy ARSA develops as a result of interruption between the right common carotid artery and the ARSA in the developing double aortic arch [9]. In the ARSA, the right fourth aortic arch and the proximal right dorsal aorta involute and the right seventh intersegmental artery develops from a persistent dorsal aorta (Figure 1). An aortic (Kommerell ` s) diverticulum may be present at the origin of this vessel, representing the remnant of the distal right aortic arch [1]. The ARSA is located posterior to the oesophagus on axial CT images, and can be seen as the last branch from the posterior margin of the aortic arch on three-dimensional images (Figure 2). The ARSA can indent the oesophagus and the trachea posteriorly, resulting in dysphagia lusoria and airway narrowing, respectively. Maethods and materials We reviewed retrospectively our archive for ARSA and its associated pathologies diagnosed between 2001 and 2003, and identified aneurysm and arteritis of ARSA and dissection of the right vertebral artery originating from ARSA. Three-dimensional non-invasive angiographic images were obtained by MR angiography and multi- detector (4- and 8-channel) CT angiography. Volume- rendered, maximum intensity projection (MIP) and multi- planar reformatted (MPR) images were obtained after the reconstruction of the axial slices. The aberrant right vertebral artery was incidentally diagnosed. Aneurysm Aneurysmal dilatation of the proximal segment of an ARSA is not infrequent, occurring in 8% of cases. Such an aneurysm can be associated with the Kommerell ` s diverticulum and is thought to develop secondary to atherosclerosis. Almost half of the cases with an ARSA Address correspondence to: Musturay Karcaaltincaba, Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey. E-mail: [email protected] The British Journal of Radiology, 82 (2009), 73–78 The British Journal of Radiology, January 2009 73
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