Developmental Aortic Arch Anomalies in Infants and Children Assessed With CT Angiography

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1 ardiopulmonary Imaging Pictorial Essay Ramos-Duran et al. T of Developmental ortic rch nomalies ardiopulmonary Imaging Pictorial Essay Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved Luis Ramos-Duran 1 John W. Nance, Jr. 1 U. Joseph Schoepf 1,2 Thomas Henzler 1,3 Paul pfaltrer 1,3 nthony M. Hlavacek 1,4 Ramos-Duran L, Nance JW Jr, Schoepf UJ, Henzler T, pfaltrer P, Hlavacek M Keywords: aortic arch, congenital heart disease, T, T angiography, vascular developmental abnormalities DOI: /JR Received pril 1, 2011; accepted after revision ugust 23, U. J. Schoepf is a medical consultant for and receives research support from ayer-schering, racco, GE Healthcare, Medrad, and Siemens Healthcare. 1 Department of Radiology and Radiological Science, Medical University of South arolina, shley River Tower, 25 ourtenay Dr, MS 226, harleston, S ddress correspondence to U. J. Schoepf (schoepf@musc.edu). 2 Department of Medicine, Division of ardiology, Medical University of South arolina, harleston, S. 3 Institute of linical Radiology and Nuclear Medicine, University Medical enter Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, aden-württemberg, Germany. 4 Department of Pediatrics, Division of ardiology, Medical University of South arolina, harleston, S. ME This article is available for ME credit. WE This is a Web exclusive article. Supplemental Data vailable online at JR 2012; 198:W466 W X/12/1985 W466 merican Roentgen Ray Society Developmental ortic rch nomalies in Infants and hildren ssessed With T ngiography OJETIVE. The purpose of this article is to review the normal anatomy of the aortic arch and the most common variations of congenital aortic arch anomalies using low-radiation-dose, defined as a dose-length product of 7 15 mgy cm, MDT angiography. ONLUSION. Radiologists should be prepared to fully describe congenital aortic arch anomalies; recognize them on T angiography, especially the presence or absence of vascular rings or aberrant arteries; and explain their association with the trachea and esophagus. nomalies in the developmental process of the aortic arch and its main branches can form vascular rings around the trachea and esophagus that may or may not be symptomatic depending on the location and degree of compression. The feasibility of surgical treatment established in 1945 [1] has made the early and accurate diagnosis of symptomatic patients vital for patient management [2]. T angiography (T), although causing concern regarding its use in pediatric patients because of ionizing radiation exposure [3], allows isotropic 3D reconstructions that assist surgeons in understanding complex anatomy for surgical planning, especially by describing the relationship between the aortic arch structures and the trachea and esophagus [4, 5]. This article illustrates the normal anatomy and most common anomalies of the aortic arch and its branches utilizing low-radiation-dose (doselength product = 7 15 mgy cm) T. Development of the ortic rch In normal embryonic morphogenesis, the aortic arch develops from five pairs of pharyngeal arch arteries with left-to-right symmetry. The mature configuration of the thoracic aorta and its branches is a result of a defined pattern of asymmetric regression and persistence of specific embryologic arch structures. Vascular rings are formed when this process does not occur normally and the resulting vasculature encircles the trachea and esophagus [6]. Normal development of the aortic arch involves the regression of the right ductus arteriosus, right dorsal aorta, and right aortic arch and the persistence of all vascular structures to the left of the trachea and esophagus (Figs. 1 and S1D [Fig. S1D can be viewed from the information box in the upper right corner of this article]). fter birth, the distal part of the left sixth aortic arch, which forms the ductus arteriosus, normally constricts to form the ligamentum arteriosum (also known as the ductal ligament ) [7]. To evaluate aortic arch anomalies, we perform non cardiac-gated T with a dualsource T scanner (Somatom Definition, Siemens Healthcare) using the following reconstruction parameters: collimation of 0.6 mm, slice thickness of 0.75 mm, reconstruction interval of 0.3 mm, tube power of 80 kv, contrast volume of 2 ml/kg of nonionic lowosmolar contrast material (300 mg I/mL iopromide [Ultravist, ayer-schering]), and kernel of b20f. Dose reduction was achieved by not using cardiac gating, which we find is not necessary to accurately assess the aortic arch and great vessels, and by using a lower tube power (80 kv) and automated tube current modulation (aredose, Siemens Healthcare). Data were transferred to a separate workstation for postprocessing and 3D reconstruction (quarius, TeraRecon). Developmental nomalies With a Left ortic rch left aortic arch with an aberrant (retroesophageal) right subclavian artery is the most common congenital aortic arch anomaly, occurring in approximately 1 in 200 individuals. ecause the right ductus arteriosus almost always disappears, this arch anomaly does not W466 JR:198, May 2012

2 T of Developmental ortic rch nomalies Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved create a true vascular ring and is not usually associated with symptomatic airway compression. However, symptoms may develop when extrinsic compression of the esophagus is caused by the retroesophageal trajectory of the aberrant right subclavian artery, which is commonly referred to as dysphagia lusoria [8] (Figs. 2 and S2E). The same anomaly, when accompanied by a persistent right ligamentum arteriosum, can create a true vascular ring leading to subtle airway compression. However, most affected patients have minimal symptoms and rarely require surgical treatment [9]. This defect may be associated with a right-sided descending aorta in which the distal arch courses posterior to the esophagus rather than the right subclavian artery. Developmental nomalies With a Right ortic rch right aortic arch is defined by the arch crossing over the right main bronchus. However, the descending aorta may run down either side of the spine. right aortic arch may result in a vascular ring depending on the branching pattern of the brachiocephalic vessels and the presence and location of a left-sided ligamentum arteriosum. Symptomatic vascular rings associated with right aortic arches are usually alleviated via transection of the ductus arteriosus or ligamentum arteriosum [4]. lthough the persistent ligamentum arteriosum cannot be seen directly via standard imaging, its presence can be inferred by an aortic diverticulum or a tethered appearance of the arch. Right ortic rch With Mirror-Image ranching right aortic arch with mirror-image branching is the second most common type of arch anomaly [6] and usually is associated with intracardiac defects (commonly tetralogy of Fallot or truncus arteriosus) and DiGeorge syndrome [10, 11] but does not usually result in a vascular ring. The brachiocephalic vessels originate from the arch in mirror-image fashion, with the left brachiocephalic artery as the first branch, followed by the right common carotid and subclavian arteries (Figs. 3 and S3D). If a right-sided ductus arteriosus persists, there is no concern for a vascular ring. When a leftsided ductus arteriosus is present, it usually originates from the brachiocephalic artery rather than from the descending aorta traveling anterior to the airway and esophagus and thus not creating a vascular ring. Rarely, a left-sided ductus arteriosus originates from the descending aorta or from an aortic diverticulum, courses posterior to the esophagus, and enters the distal main pulmonary artery to create a vascular ring [12] (Figs. 4 and S4). Right ortic rch With an berrant Left Subclavian rtery right aortic arch accompanied by an aberrant left subclavian artery and retroesophageal diverticulum results from the interruption of the left fourth aortic arch between the left common carotid artery and left subclavian artery during development [6]. From the right aortic arch, the left common carotid arises as a first branch, followed by the right common carotid and subclavian arteries. The left subclavian artery is supplied by a diverticulum distal to the right subclavian artery that courses posterior to the esophagus, resulting in posterior esophageal compression (Figs. 5 and S5). The remnant of the left dorsal aortic root may appear as a pouch, which is known as Kommerell diverticulum [11]. The ring is completed by a left-sided ductus arteriosus (or ligamentum arteriosum) extending from the diverticulum to the proximal left pulmonary artery. The retroesophageal diverticulum is differentiated from a retroesophageal left subclavian artery without a diverticulum (described later in this article) by its caliber, which is usually similar to that of the aorta (Fig. 6). Rarely, a right aortic arch can be accompanied by an aberrant left subclavian in the absence of a retroesophageal diverticulum [11]. In contrast to patients with a retroesophageal diverticulum, the ductus arteriosus is absent, is right-sided, or originates from the left carotid. Therefore, a vascular ring is not created. However, symptoms may develop because of extrinsic compression of the esophagus by the retroesophageal trajectory of the aberrant left subclavian artery (Figs. 7 and S7D). This arch anatomy usually occurs in the presence of conotruncal abnormalities such as tetralogy of Fallot or truncus arteriosus [10]. Right ortic rch With a Left Descending orta right aortic arch with a left descending aorta and left ductus arteriosus or ligamentum arteriosum, also known as circumflex retroesophageal right aortic arch [13], has a presentation similar to right arches with retroesophageal diverticula but is much less common. In contrast to the previous two anomalies, the distal arch courses posterior to the esophagus and a left-sided ligamentum arteriosum from the descending aorta to the left pulmonary artery completes the vascular ring. This anomaly may also be accompanied by an aberrant left subclavian artery (Figs. 8 and S8). Like most vascular rings, relief may be provided by transection of the ligamentum arteriosum. However, patients with severe symptoms may require transection of the distal arch with mobilization of the retroesophageal portion and reanastomosis of the ascending and descending aorta left of the trachea. Right ortic rch With an berrant rachiocephalic rtery right aortic arch with an aberrant brachiocephalic artery is an uncommon anomaly that is similar to a right aortic arch with an aberrant left subclavian artery and retroesophageal diverticulum [14]. ontrary to the general rule that the first arch vessel courses contralateral to the side of the arch, the first arch vessel in this anomaly is the right carotid, followed by the right subclavian artery and a retroesophageal brachiocephalic artery. Usually, the brachiocephalic artery originates from a diverticulum that also supplies a left-sided ductus or ligamentum arteriosum to the proximal left pulmonary artery, completing a vascular ring (Figs. 9 and S9D). Developmental nomalies With a Double ortic rch double aortic arch completely encircles the trachea and esophagus by connected segments of the arch and its branches (Fig. 10). oth arches may be patent, or a segment of one arch may be atretic, persisting as a ligamentous structure. cervical arch on either side, variable laterality of the descending thoracic aorta, coarctation of the major arch, or discontinuity of the central pulmonary arteries may also be present. More than 80% of patients with double aortic arch have a rightdominant system [15] (Figs. 11 and S11D), and the left arch is usually patent rather than atretic. When the minor arch is severely hypoplastic or atretic, the affected segment is almost always distal to the left subclavian artery (Figs. 12, S12, and 13), although it may also be found between the common carotid and subclavian arteries. In patients with a leftdominant system, the right arch is typically patent (Fig. 14). In symptomatic patients with JR:198, May 2012 W467

3 Ramos-Duran et al. Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved double aortic arch, surgical planning is directed toward transection of either the smallest arch (if both arches are patent) or an atretic arch segment [16]. onclusion The spectrum of aortic arch anomalies is diverse, and diagnostic imaging is needed to elucidate the complex vascular anatomy of patients with suspected aortic arch anomalies. Specifically, the relationship of the arch vessels with the aerodigestive tract, right or left dominance in patients with a double aortic arch, persistence of left or right ductus arteriosus or ligamentum arteriosum, and the presence of a retroesophageal diverticulum are important to describe because these factors are critical to surgical planning. References 1. Gross RE. Surgical relief for tracheal obstruction from a vascular ring. N Engl J Med 1945; 233: Kagadis G, Panagiotopoulou E, Priftis KN, Vaos G, Nikiforidis G, nthracopoulos M. Preoperative evaluation of the trachea in a child with pulmonary artery sling using 3-dimensional computed tomographic imaging and virtual bronchoscopy. J Pediatr Surg 2007; 42:E9 E13 3. Goo HW, Suh DS. Tube current reduction in pediatric non-eg-gated heart T by combined tube current modulation. Pediatr Radiol 2006; 36: acker L, Mavroudis, Rigsby K, Holinger LD. Trends in vascular ring surgery. J Thorac ardiovasc Surg 2005; 129: Turkvatan, uyukbayraktar FG, Olcer T, umhur T. ongenital anomalies of the aortic arch: evaluation with the use of multidetector computed tomography. Korean J Radiol 2009; 10: Weinburg PM. ortic arch anomalies. In: llen HD, Driscoll DD, Shaddy RE, Feltes TF, eds. Moss and dams heart disease in infants, children, and adolescents: including the fetus and young adult. Philadelphia, P: Lippincott Williams & Wilkins, 2008: Edwards JE. nomalies of the derivatives of the aortic arch system. Med lin North m 1948; 32: sherson N. David ayford: his syndrome and sign of dysphagia lusoria. nn R oll Surg Engl 1979; 61: Humphrey, Duncan K, Fletcher S. Decade of experience with vascular rings at a single institution. Pediatrics 2006; 117:e903 e acker L, Mavroudis. ongenital Heart Surgery Nomenclature and Database Project: vascular rings, tracheal stenosis, pectus excavatum. nn Thorac Surg 2000; 69(suppl 4):S308 S Knight L, Edwards JE. Right aortic arch: types and associated cardiac anomalies. irculation 1974; 50: Garti IJ, ygen MM, Vidne, Levy MJ. Right aortic arch with mirror-image branching causing vascular ring: a new classification of the right aortic arch patterns. r J Radiol 1973; 46: Hilmes M, Hernandez R, Devaney E. Markedly hypoplastic circumflex retroesophageal right aortic arch: MR imaging and surgical implications. Pediatr Radiol 2007; 37: Garti IJ, ygen MM. Right aortic arch with aberrant left innominate artery. Pediatr Radiol 1979; 8: Yoo SJ, radley TJ. Vascular rings: pulmonary arterial sling, and related conditions. In: nderson RH, aker EJ, Redington, Rigby ML, Penny D, Wernovsky G, eds. Paediatric cardiology, 3rd ed. Philadelphia, P: hurchill Livingstone, 2009: lsenaidi K, Gurofsky R, Karamlou T, Williams WG, Mcrindle W. Management and outcomes of double aortic arch in 81 patients. Pediatrics 2006; 118:e1336 e1341 Fig. 1 hest T angiography study of 8-year-old boy with dysphagia displays normal left aortic arch. See also Figure S1D, which can be viewed from the information box in the upper right corner of this article., Frontal (), anterocranial (), and right oblique posterior () 3D volume-rendered images show normal left aortic arch crossing craniad to left main bronchus (yellow arrow, ) with aortic arch and branches () situated to left of trachea (white arrows). These findings indicate that this child s dysphagia is not result of aortic arch malformation. Protocol used 80 kv and 34 ms; dose-length product was 15 mgy cm. W468 JR:198, May 2012

4 T of Developmental ortic rch nomalies Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved D Fig. 2 hest T angiography study of 5-year-old girl with dysphagia shows left aortic arch with aberrant right subclavian artery. See also Figure S2E, which can be viewed from the information box in the upper right corner of this article. D, Frontal (), superior (), and oblique right posterior () 3D volume-rendered images and 2D 3-mm coronal multiplanar reconstruction (D) show aortic arch (, ) crossing craniad to left main bronchus (yellow arrow, ) and leftward of trachea (white arrows, ). Right subclavian artery (RS) courses posterior to esophagus (E, D), resulting in extrinsic compression (asterisks, and D). lthough this malformation has been associated with dysphagia, this patient does not have true vascular ring. Protocol used 80 kv and 29 ms; dose-length product was 10 mgy cm. Fig. 3 hest T angiography study of 3-month-old male infant with repaired tetralogy of Fallot shows right aortic arch with mirror-image branching pattern and rightsided descending aorta. He did not have symptoms suggestive of vascular ring; study was requested to evaluate pulmonary artery stenosis. See also Figure S3D, which can be viewed from the information box in the upper right corner of this article., Frontal (), superior (), and oblique left posterior () 3D volume-rendering images show aortic arch () crossing craniad to right main bronchus (yellow arrow, ) and rightward of trachea (white arrows) and nasogastric tube (NGT, and ) seen in esophagus. Note that left brachiocephalic artery (, and ) arises as first branch, followed by right common carotid (R, and ). Remnant of left-sided ductus arteriosus (asterisk, ), which was ligated at surgery, is seen originating from brachiocephalic artery. This patient does not have a vascular ring. Protocol used 80 kv and 29 ms; dose-length product was 7 mgy cm. JR:198, May 2012 W469

5 Ramos-Duran et al. Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved Fig. 4 hest T angiography study of 15-month-old boy with poor feeding displays right aortic arch with mirror-image branching pattern and retroesophageal diverticulum. See also Figure S4, which can be viewed from the information box in the upper right corner of this article. and, Frontal () and left oblique posterior () 3D volume-rendering images show aortic arch (, ) crossing to right of trachea (white arrows) with mirror-image branching of aorta. Left-sided retroesophageal diverticulum (asterisks) indicates location of ligamentum arteriosum (dotted line, ) connecting distal main pulmonary artery (MP, ) to descending aorta, completing vascular ring. This patient underwent transection of left-sided ligamentum arteriosum. Protocol used was 80 kv and 25 ms; dose-length product was 7 mgy cm. Fig. 5 hest T angiography study of 7-month-old male infant with feeding difficulties shows right aortic arch with retroesophageal aortic diverticulum and aberrant left subclavian artery. See also Figure S5, which can be viewed from the information box in the upper right corner of this article. and, Frontal 3D volume-rendering images show aortic arch (, ) crossing craniad to right main bronchus (yellow arrow, ). Note that origin of left subclavian artery (LS) arises from retroesophageal diverticulum (asterisk, ) located distal to right subclavian artery (RS, ). There is extrinsic compression of esophagus (E, ) by diverticulum. Left-sided ligamentum arteriosum from diverticulum to left pulmonary artery (shown in Fig. 6) completes vascular ring. This patient underwent transection of left-sided ligamentum arteriosum. Protocol used was 80 kv and 24 ms; dose-length product was 8 mgy cm. Fig. 6 hest T angiography study of 7-month-old male infant (same patient shown in Fig. 5) with right aortic arch with retroesophageal diverticulum and aberrant left subclavian artery seen in Figure 5. and, Three-dimensional volume-rendering images obtained using sequential superior perspective show aortic arch () to right of trachea (white arrows). First branch off arch is left common carotid (L, ). Left subclavian artery (LS, ) originates from retroesophageal diverticulum (asterisk, ). Vascular ring is completed by left-sided ligamentum arteriosum (dotted line, ) passing from retroesophageal diverticulum (asterisk, ) to distal main pulmonary artery (MP, ). Retroesophageal diverticulum is distinguished from aberrant left subclavian artery without left-sided ligamentum or diverticulum, as seen in Figure 7, by its caliber, which is similar to that of aorta. W470 JR:198, May 2012

6 T of Developmental ortic rch nomalies Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved Fig. 7 hest T angiography study of 4-year-old boy with repaired tetralogy of Fallot shows right aortic arch with retroesophageal left subclavian artery. He did not have symptoms suggestive of vascular ring; study was requested to evaluate distal pulmonary artery stenosis. See also Figure S7D, which can be viewed from the information box in the upper right corner of this article., Frontal (), superior (), and left oblique posterior () 3D volume-rendering images show aortic arch (, and ) crossing craniad to right main bronchus (yellow arrow, ). First branch off arch is left common carotid (L, and ). Note that left subclavian artery (LS, and ) courses posterior to trachea (white arrows, and ). Unlike cases shown in Figures 5 and 6, left subclavian artery originates directly from aorta (rather than from diverticulum) and has uniform caliber and course. This defect is not true vascular ring. Protocol used was 80 kv and 29 ms; dose-length product was 10 mgy cm. Fig. 8 hest T angiography study of 2-year-old girl with dysphagia shows right aortic arch with aberrant left subclavian and left-sided descending aorta. See also Figure S8, which can be viewed from the information box in the upper right corner of this article. and, Frontal () and superior () 3D volumerendering images show proximal aortic arch () crossing craniad to right main bronchus (yellow arrow, ) and rightward of trachea (white arrows) with retroesophageal trajectory of distal arch (asterisk, ), left-sided descending aorta (D), and aberrant left subclavian artery (LS). Left-sided ductal ligament from descending aorta to left pulmonary artery (not seen) completes vascular ring in this patient. Patient protocol used was 80 kv and 28 ms; dose-length product was 10 mgy cm. JR:198, May 2012 W471

7 Ramos-Duran et al. Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved Fig. 9 hest T angiography study of 2-year-old boy with frequent respiratory infections shows right aortic arch with aberrant brachiocephalic artery. See also Figure S9D, which can be viewed from the information box in the upper right corner of this article., nterior (), superior (), and oblique left () 3D volume-rendering images show right aortic arch (, and ) coursing superior to right main bronchus (yellow arrow, ) and rightward of trachea (white arrows, and ). There is aberrant brachiocephalic artery () arising from retroesophageal diverticulum (asterisk, ). Left common carotid (L, and ) and left subclavian artery (LS, and ) can be seen originating from brachiocephalic artery. Diverticulum attaches via ligamentum arteriosum (dotted line, ) to distal main pulmonary artery (MP, ), completing vascular ring. This patient underwent transection of left-sided ligamentum arteriosum. Protocol used was 80 kv and 28 ms; dose-length product was 11 mgy cm. Fig. 10 hest T angiography study of 6-year-old girl with recurrent respiratory symptoms shows left-dominant double aortic arch., nterior (), posterior (), and superior () 3D volume-rendering images show bilaterally patent double aortic arch with similarly sized arches. Each arch gives rise to ipsilateral carotid and subclavian arteries encircling and compressing trachea (white arrows, and ). Given that left arch (L) is slightly larger than right arch (R), right arch was transected at surgical repair. Protocol used was 80 kv and 28 ms; dose-length product was 11 mgy cm. W472 JR:198, May 2012

8 T of Developmental ortic rch nomalies Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved Fig. 11 hest T angiography study of 11-month-old male infant with stridor shows right-dominant double aortic arch. See also Figure S11D, which can be viewed from the information box in the upper right corner of this article., nterior (), posterior (), and superior () 3D volume-rendering images show bilaterally patent double aortic arch. Most commonly, right arch (R) is dominant to left arch (L). Each arch gives rise to ipsilateral carotid and subclavian arteries. Note more cranial position of dominant right-sided arch and that trachea (white arrows, and ) and esophagus (yellow arrow, ) are encircled and compressed. This patient underwent surgical transaction of left arch distal to subclavian artery. Protocol used was 80 kv and 26 ms; dose-length product was 9 mgy cm. Fig. 12 hest T angiography study of 7-year-old boy with dysphagia shows right-dominant double aortic arch. See also Figure S12, which can be viewed from the information box in the upper right corner of this article. and, oronal () and axial () 2D minimumintensity-projection images show double aortic arch with dominant right arch (R). Note that left arch (L) is nearly atretic (yellow arrows) distal to left subclavian artery (LS, ). Protocol used was 80 kv and 39 ms; dose-length product was 12 mgy cm. Fig. 13 hest T angiography study of 7-year-old boy (same patient shown in Fig. 12) with rightdominant double aortic arch seen in Figure 12. and, nterior () and oblique left posterior () 3D volume-rendering images show double aortic arch with dominant right arch (R). Small left-sided ductus arteriosus (asterisks), connecting left arch (L) to distal main pulmonary artery (MP, ), is also seen. Note that segment distal to left subclavian artery (LS, ) is nearly atretic. This portion of arch, along with ductus arteriosus, was transected at surgical repair. JR:198, May 2012 W473

9 Ramos-Duran et al. Downloaded from by on 05/13/18 from IP address opyright RRS. For personal use only; all rights reserved FOR YOUR INFORMTION The data supplement accompanying this Web exclusive article can be viewed from the information box in the upper right corner of the article at: FOR YOUR INFORMTION Fig. 14 hest T angiography study of newborn female who was intubated because of stridor and respiratory distress shows left-dominant double aortic arch., nterior (), posterior (), and superior () 3D volume-rendered images show bilaterally patent double aortic arch with asymmetrically sized arches, encircling endotracheal tube (white arrows, and ). Note that left arch (L) is larger than right arch (R), which is uncommon in this anomaly. Patient underwent surgical transaction of right arch distal to right subclavian artery (RS, ). Protocol used was 80 kv and 29 ms; dose-length product was 11 mgy cm. This article is available for ME credit. Log on to click on JR (in the blue Publications box); click on the article name; add the article to the cart; proceed through the checkout process. W474 JR:198, May 2012