An atrial septal aneurysm (ASA) is an uncommon cardiac abnormality. Clinical
manifestation of this abnormality remains unclear: some authors have suggested
an association between ASA and arrhythmias or between ASA and cerebral
ischaemia. A major role in the diagnosis of ASA to date has been played
by transoesophageal echocardiography and transthoracic echocardiography.
The purpose of this paper is to present the role of multi-slice computed tomography
with ECG gating in the detection and analysis of ASA. (Folia Morphol
2008; 67: 126&#8211;128

Czekajska-Chehab, E.

Drop, A.

Siek, E.

Tomaszewska, M.

Tomaszewski, A.

Uhlig, S.

English

Via Medica Journals

Folia Morphol. Vol. 67, No. 2, pp. 126–128Copyright © 2008 Via MedicaISSN 0015–5659www.fm.viamedica.plO R I G I N A L   A R T I C L E126Address for correspondence: E. Czekajska-Chebab, 1st Department of Radiology, Medical University of Lublin, Orkana 17/24, 20–504 Lublin,Poland, e-mail: mon.tomaszewska@gmail.comECG-gated multi-slice computed tomographyin the detection of atrial septal aneurysmsE. Czekajska-Chehab1, A. Tomaszewski2, M. Tomaszewska1,E. Siek2, S. Uhlig1, A. Drop1 11st Department of Radiology, Medical University of Lublin, Poland2Department of Cardiology, Medical University of Lublin, Poland[Received 6 January 2008; Accepted 13 April 2008]An atrial septal aneurysm (ASA) is an uncommon cardiac abnormality. Clinicalmanifestation of this abnormality remains unclear: some authors have sug-gested an association between ASA and arrhythmias or between ASA and ce-rebral ischaemia. A major role in the diagnosis of ASA to date has been playedby transoesophageal echocardiography and transthoracic echocardiography.The purpose of this paper is to present the role of multi-slice computed tomo-graphy with ECG gating in the detection and analysis of ASA. (Folia Morphol2008; 67: 126–128)Key words: atrial septal aneurysm, multi-slice computedtomographyINTRODUCTIONAtrial septal aneurysms (ASA) are rare congeni-tal malformations, where the interatrial septum (IAS)protrudes into the right or left atrium or both [6].Anatomically it is a bulge in the region of the os-tium primum [3]. Atrial septal aneurysm can be anisolated malformation but is very often associatedwith other cardiac anomalies. The most frequentanomalies which coexist with ASA are patent fora-men ovale and mitral valve prolapse.Clinical manifestation of this malformation is stillpoorly defined. Some authors have suggested anassociation with arrhythmias. Many data also sug-gest an association between ASA and cerebral is-chaemia. There is still controversy concerning theincidence of ASA in the general population, as theincidence depends on the diagnostic method whichwas used to detect ASA. The reported incidence ofASA varies from 2% to 10% [3].To date, it has been echocardiography, transtho-racic and transoesophageal, which has played themajor role in the diagnostic process of this anoma-ly. There is still unfamiliarity with this anomalyamong radiologists. To our knowledge, only onepaper published in 2006 attributed the major rolein the diagnostic process of detecting ASA to com-puted tomography [6].The purpose of this paper is to present the roleof multi-slice computed tomography (MSCT) in thediagnosis of ASA and to establish the frequency ofthis anomaly among patients examined in our De-partment.MATERIAL AND METHODSMedical histories and databases were analysedfor a group of 1650 patients examined due to theoccurrence of ASA in 1st Department of Radiologyof the Medical University of Lublin in the years 2002––2006. In most cases patients had been referred forMSCT examination with ischaemic heart disease.Examinations were performed using 8-row and64-row MSCT with the diagnostic console Advantage127E. Czekajska-Chehab et al., ECG-gated MSCT in the detecion of atrial septal aneurysmsWindows 4.0 (General Electric Milwaukee). Pre-contrast scanning was conducted with ECG gat-ing by means of the axial method in 2.5-mm slic-es and post-contrast spiral scanning with collima-tion of 1.25 mm (8-row CT) or of 0.6 mm (64-rowCT). The optimal scanning time was based on thedensity measurement after the administration ofthe test bolus technique. The contrast medium wasadministered in a dose of 140 mL (8-row CT) and120 ml (64-row CT) at a speed of 4 mL/s. The scanswere reconstructed from 0% to 95% R-R cycle at10% intervals. The image data sets were analysedusing multiplanar reconstructions.Atrial septal aneurysms was defined by the au-thors as protrusion of the IAS showing phasic ex-cursion during the cardiorespiratory cycle (Fig. 1A).After analysing a few examinations the authorschose the phases at 45% and 95% of the R-R cycleas the best for the analysis of ASA. The diameter ofthe aneurysmatic portion of the IAS was measuredat 45% of the R-R cycle and protrusion into the atri-um at 45% and 95% of the R-R cycle (Fig. 1B).RESULTSOf the group of 1650 patients examined in ourDepartment 22 were found to have ASA, of whom17 were women and 5 men. In all these patientsthe ASA was localised at the typical site of theostium primum. In 21 patients ASA was a loneanomaly. In one patient interatrial shunting wasobserved through the foramen in the wall of theaneurysm (Fig. 2). Mitral and tricuspid insufficiencywas found in two patients. There were two casesof patent foramen ovale diagnosed in echocardio-graphy.It is postulated that the surface of the ASA isa source of thrombus formation. We did not findany thromboses on the surface of the ASA in ourgroup of patients. Some authors also suggest anassociation with arrhythmias. In the group analy-sed three patients had atrial fibrillation.In all cases the IAS protruded into the right atri-um. In 13 patients (59%) protrusion of IAS in thehorizontal size increased at 95% of the R-R cycle.The minimal excursion of ASA in the 45% and 95%phase was 0.7 mm and the maximal excursion ofASA was 6.6 mm in the horizontal size. The meanvalue of the ASA excursion was 2.32 mm.Figure 2. Multi-slice computed tomography with ECG-gating inaxial MPR-view at 95% of R-R cycle showing interatrial shuntingthrough the foramen in the wall of the atrial septal aneurysm(white arrow).Figure 1A. Multi-slice computed tomography with ECG-gating in axial MPR-view at 45% of R-R cycle showing protrusion of interatrial septuminto the right atrium (white arrow); B. Multi-slice computed tomography with ECG-gating in axial MPR view at 45% of R-R cycle; (—) — thediameter of aneurysmatic portion of the interatrial septum in the longitudinal size; ≠ — protrusion of interatrial septum in the horizontal size.A B128Folia Morphol., 2008, Vol. 67, No. 2either protrusion of the ASA ≥ 15 mm beyond theplane of the IAS or phasic excursion of the IAS ≥ 15 mmin total amplitude during the cardiorespiratory cycle.However, this definition is not commonly used inclinical practice. Our criterion for ASA was visibleprotrusion of the IAS, showing phasic excursionduring the cardiorespiratory cycle.The incidence of ASA in the adult population re-ported in the literature varies from 2% to 10% [3].Most ASA cases are detected incidentally. In our studywe found ASA in 22 patients (1.33%) in a group of1650. In our study the detection rate for the anoma-ly increased with our diagnostic ability. In the year2004 we detected two cases of ASA, in the year 20056 cases and in the year 2006 14 cases!To our knowledge there is only one case reportin the world literature where MSCT was the maindiagnostic tool for detecting ASA [6]. Atrial septalaneurysms is poorly known by radiologists. The firststep in recognising this anomaly is to know that suchmalformation may occur. It seems that MSCT withECG gating is extremely sensitive in the diagnosis ofASA. Multi-slice computed tomography enables ASAand associated heart anomalies to be accurately vi-sualised. In our opinion MSCT, especially with ECGgating, which precisely visualises the anatomicaldetails of the atrial septum, is a valuable method inthe diagnosis of ASA.REFERENCES1. Agmon Y, Khandheria BK, Meissner I, Gentile F,Whisnant JP, Sicks JrD, O’Fallon WM, Covalt JL,Wiebers DO, Seward JB (1999) Frequency of atrial sep-tal aneurysms in patients with cerebral ischemic events.Circulation, 99: 1942–1944.2. Hanley P, Tajik A, Hynes J, Edwards W, Seward J (1985)Diagnosis and classification of atrial septal aneurysmby two-dimensional echocardiography: report of80 consecutive cases. J Am Coll Cardiol, 6: 1370–1382.3. Madan V, Harkness K, Brien EO, Warburton EA (2005)Lone atrial septal aneurysm and stroke: a case report andreview of the literature. Eur J Inter Med, 16: 520–522.4. Moorthy SS, Diedorf SF (1996) Significance of atrial an-eurysm: report of a case. J Clin Anesthesia, 8: 595–597.5. Mugge A, Daniel W, Angermann C, Spes C, Khandheria BK,Kronzon I, Freedberg RS, Keren A, Dennig K, Engberding R,Sutherland GR, Vered Z, Erbel R, Visser CA, Lindert O,Hausmann D, Wenzlaff P (1995) Atrial septal aneurysmin adult patients. Circulation, 91: 2785–2792.6. Zeina AR, Orlov I, Sharif D, Barmeir E (2006) Detectionof atrial septal aneurysm by ECG-gated MDCT. AJR, 187:229–230.The diameter of the base of ASA was measuredin 45% of R-R cycle and ranged from 13 mm to39 mm in the longitudinal size.DISCUSSIONAtrial septal aneurysms are incidentally found inadult patients. The aetiology of this anomaly is un-clear. It is supposed that ASA formation is connectedwith raised interatrial pressure gradients and the bulg-ing septum protrudes to the lower pressure side. Some-times, however, this malformation is found in patientswith normal atrial pressure, and it is then recognisedas a primary or congenital malformation [5].Atrial septal aneurysm is regarded as a cardiacanomaly associated with systemic embolisation [4] andcardiac arrhythmias [5]. Mugge et al. [5] noted 47 casesof atrial arrhythmias in 195 patients with ASA (24%).However, it is unclear whether the redundancy of theatrial septum itself or other associated anomalies areconnected with the pathogenesis of atrial arrhythmias.In our group of patients three had atrial fibrillation.Atrial septal aneurysms is considered to bea potential risk factor for cardioembolism [1]. Anassociation between ischaemic cerebral stroke andASA has been suggested in the literature. Agmon etal. [1] compared the frequency of ASA in the gener-al population and in patients with cerebral ischaemicstroke. Atrial septal aneurysm was detected in 7.9%of patients with cerebral stroke compared to 2.2%in the general population [1]. Agmon et al. [1] alsopresented a higher proportion of ASA in patientsafter cerebral ischaemia (7.9%) than in the generalpopulation (2.2%). Cerebral stroke can be causedby a paradoxical embolism from a right-to-left shuntat atrial level. It has also been suggested that ASA isa source of thrombus formation [5].Atrial septal aneurysms can be an isolated cardi-ac malformation. However, it is frequently concom-itant with other cardiac anomalies such as atrial sep-tal defects, including patent foramen ovale. Agmonet al. [1] also noted mitral valve prolapse in 20.5%and tricuspid prolapse in 7.2% of patients with ASA.The incidence of ASA in the population is stillunclear. Detection of this anomaly depends on thediagnostic method used and various diagnostic cri-teria. According to the echocardiographic definitionpublished by Hanley et al. [2], ASA is recognisedwhen the diameter of the base of the aneurysmaticportion of the IAS measures ≥ 15 mm and there is

ECG-gated multi-slice computed tomography in the detection of atrial septal aneurysms

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ECG-gated multi-slice computed tomography in the detection of atrial septal aneurysms

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