Search

Objectives The purpose of this study was to perform a head-to-head comparison between multislice computed tomography (MSCT) and intracardiac echocardiography (ICE). Background Different imaging techniques have been used to visualize the pulmonary veins (PV) before radiofrequency ablation of atrial fibrillation. Methods The PV and their atrial insertion were evaluated in 42 patients (35 men, 49 ± 9 years) admitted for ablation of PV ostia. Ostia were measured in two directions (anterior-posterior and superior-inferior) with MSCT. Two-dimensional (2-D) measurements of PV ostia were performed with ICE. Results were compared, considering MSCT as the gold standard. Venous ostium indexes were calculated by dividing MSCT measurements in the anterior-posterior direction and the superior-inferior direction. Results Common ostia of left PV were observed in 33 (79%) patients with MSCT and 31 (74%) patients with ICE. Common ostia of right PV were observed in 13 (31%) and 16 (38%) patients, respectively. Additional PV were observed in 13 (31%) patients with MSCT and in 7 (17%) patients with ICE. Ostial diameters by MSCT in the anterior-posterior direction were similar to 2-D measurements by ICE. By contrast, diameters by MSCT in the superior-inferior direction were significantly larger than 2-D diameters measured with ICE. Venous ostium indexes were 0.77 ± 0.18 and 0.90 ± 0.15 (p Conclusions Variation in PV anatomy is frequently observed with both techniques. The sensitivity for detection of additional branches is higher for MSCT. Results of measurements of PV ostia suggest an underestimation of ostial size by ICE. Three-dimensional imaging techniques, such as MSCT, are required to demonstrate an oval shape of PV ostia.

Multidetector row Computed Tomography (MDCT) is developing rapidly as a potential non-invasive imaging method for the direct visualization of coronary arteries in patients presenting with suspected coronary artery disease. Recent technical improvements have led to improved spatial and temporal resolution and may even allow evaluation of coronary stents, which has remained difficult due to the small diameter and radio-opaque material. We describe two cases, a 65- and a 72-year old patient. Both patients had previously undergone percutaneous transluminal coronary angioplasty in combination with stent placement and were re-admitted to our hospital with recurrent angina. MDCT was performed prior to or after coronary angiography in order to assess stent patency non-invasively.

Multi-slice computed tomography (MSCT) is developing rapidly as a potential non-invasive imaging method for the evaluation of coronary arteries in patients presenting with chest pain. Recent technical improvements have led to improved spatial and temporal resolution and may even allow MSCT to be useful in the evaluation of coronary stents, which has remained difficult due to the small diameter and radio-opaque material. We describe two cases, a 61-year-old male and a 65-year-old female. Both patients had previously undergone percutaneous transluminal coronary angioplasty in combination with stent placement and were re-admitted to our hospital with recurrent angina. MSCT was performed prior to conventional coronary angiography in order to assess stent patency non-invasively.

Purpose To evaluate the effect of including the first-pass of a blood pool agent (BPA) on the image quality of three-dimensional navigator coronary MRA. Materials and Methods A pig model was used to perform: 1) T1 simulation of the BPA, based on actual blood samples, and 2) BPA-enhanced three-dimensional navigator coronary MRA, with or without inclusion of the first-pass of the BPA. The acquisitions with inclusion of the first-pass were timed with the use of a test bolus. The acquisitions without first-pass were started one minute after bolus injection (steady-state). A gradient echo acquisition technique with centric k-space sampling was applied. Comparison of both acquisitions was based on determination of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and vessel length. Results T1 simulation shows a distinct T1 reduction during first-pass (to a level below 50 msec), increasing to 190 msec during steady-state. Images obtained with first-pass inclusion showed improved CNR (8.6 ± 1.7 vs. 4.5 ± 1.8), SNR (11.9 ± 1.6 vs. 7.4 ± 2.0), and vessel length (99.2 ± 10.9 mm vs. 60.5 ± 21.8 mm) as compared to the acquisitions during steady-state only (all: P< 0.05). Conclusion The image quality of three-dimensional navigator coronary MRA combined with a gadolinium BPA in pigs is improved when starting the image acquisition during first-pass of the bolus. J. Magn. Reson. Imaging 2003;18:502–506. © 2003 Wiley-Liss, Inc.

Atrial fibrillation is the most common arrhythmia, with an increasing prevalence at higher age. Besides symptoms that affect quality of life, there is a significant risk of thromboembolic complications, heart failure and death. Different therapeutic options are proposed. Results of pharmacological treatment are often disappointing. Adverse side effects of antiarrhythmic medication are considerable and pro-arrhythmic effects may occur. Over the recent years, interest in nonpharmacological therapies for atrial fibrillation has increased. Besides the development of techniques focusing on rate-control, such as His bundle ablation, surgical techniques aiming at restoration of sinus rhythm have been developed. In addition, intra-operative application of radiofrequency current has been proposed and several catheter-based techniques have been developed. The observation that ectopic foci originating in the pulmonary veins can initiate atrial fibrillation, has stimulated the development of percutaneous ablation strategies aiming at ablation at the site of the pulmonary veins. Results are promising, but at the cost of long procedure times and serious procedure-related complications. These issues are (in part) related to the fact that the ablation targets, namely the veno-atrial junctions and the pulmonary veins or their ostia, are not easily visualized using fluoroscopy alone. Furthermore, fluoroscopy does not allow identification of anatomical intra-cardiac structures accurately and cannot be used to verify adequate catheter–tissue contact. Accurate catheter positioning is therefore difficult. These problems can partly be overcome by the use of threedimensional electro-anatomic mapping systems and intra-cardiac echocardiography during the ablation procedure; in addition, non-invasive imaging of the pulmonary veins using magnetic resonance techniques or multi-slice computed tomography will allow planning of the ablation strategy prior to the ablation procedure. The aim of this case report is to describe the integrated use of different imaging modalities in the treatment of atrial fibrillation by radiofrequency catheter ablation. We have performed multi-slice computed tomography prior to radiofrequency catheter ablation to obtain information on the number/location of the pulmonary veins, their ostia and eventual anomalies. During the radiofrequency catheter ablation procedure, intra-cardiac echocardiography was used to determine catheter position in relation to the anatomic structures, assessment of catheter–tissue contact and evaluation of potential complications. A nonfluoroscopic mapping and navigation system provided electrophysiologic information, during the procedure and constructed a three-dimensional model in which ablation lesions could be marked.

Magnetic resonance angiography (MRA) is a promising method for noninvasive coronary artery imaging. The interesting features of coronary MRA are its non-invasive nature, the absence of ionizing radiation, and the possibility of imaging the coronary arteries without exogenous contrast. Moreover, three-dimensional volume information and tomographic image planes in any direction can be obtained. The current review presents an overview of the recent technical developments of coronary MRA and the potential clinical applications. New MR techniques, such as parallel image acquisition, spiral imaging, steady-state free precession and the introduction of blood pool contrast agents may result in more efficient data acquisition. After implementation of these fast techniques, coronary MRA may be integrated in a comprehensive cardiac exam.

Coronary artery anomalies occur in 0.3-0.8% of the population and infer a high risk for sudden cardiac death in young adults. Diagnosis is usually established during coronary angiography, which is hampered by poor spatial visualization. Magnetic resonance imaging is an alternative, but it is not feasible in the presence of metal objects or claustrophobia. In this report, a 15-year-old boy experienced ventricular fibrillation and was successfully resuscitated. Cardiac catheterization was inconclusive, and pacemaker implantation prohibited the use of MR imaging. Multi-slice CT coronary angiography revealed a malignant anomalous right coronary artery.

F efficient cardiac patient management, a comprehensive noninvasive cardiac examination is desirable. Multislice computed tomography (CT) has the potential to assess coronary artery stenosis.1,2 Multislice CT may assess left ventricular (LV) function in addition, without the need for extra acquisitions. The purpose of the present study was to apply dynamic multislice CT for the assessment of regional wall motion and global cardiac function in patients with unstable angina, and to compare the results with conventional 2-dimensional echocardiography. • • • Fifteen patients (mean age 59 11 years) presenting with complaints of unstable angina were included in the present study. Typical electrocardiographic changes (ST-segment depression) were present in 13 patients. Six patients had had a previous infarction ( 3 months before the study), and 1 patient had previously undergone coronary artery bypass graft surgery. All patients had 1 risk factor for coronary artery disease. All patients underwent conventional 2-dimensional echocardiography followed by contrast-enhanced multislice CT on the same day. Informed consent and ethics approval was obtained for all patients. CT studies were performed on a Toshiba MultiSlice Aquilion 0.5 system (Toshiba Medical Systems, Otawara, Japan). Nonionic contrast material (Xenetix, Guerbet, Aulnay S. Bois, France) (140 ml, flow rate 4.0 ml/s) was injected into the antecubital vein. The bolus arrival was automatically detected using peak enhancement detection in the aortic root. Helical CT scanning was begun using simultaneous acquisition of 4 sections with a collimated slice thickness of 2 mm, helical pitch of 1 mm/0.5 second, and 500 ms rotation time. Tube voltage was 120 kV at 250 mA. The heart was imaged from aortic root to diaphragm. Depending on heart rate and heart size, the breath-hold time was 20 to 35 seconds and the temporal resolution was 160 ms. A segmental reconstruction algorithm was used to allow for the inclusion of patients with a range of heart rates without the need for preoxygenation or -blocker therapy. The image data were reconstructed to 1-mm overcontiguous slices. With the recorded electrocardiogram, retrospective reconstruction was performed for the acquisition of phase images starting from early systole (0% of the RR interval) to the end of diastole (95% of the RR interval) using 5% increasing steps, thus obtaining 20 heart phases. Multiplanar reformats were created to obtain 2-chamber, 4-chamber, and short-axis orientations according to previously published methods.3,4 The data were stored in DICOM format and transferred to a dedicated cardiac analysis software utility (CT-MASS, MEDIS Medical Imaging Systems, Leiden, The Netherlands) running on a Linux workstation. Regional wall motion was assessed in a blinded fashion using the multiplanar reformat cinematic loops and the 17-segment model as recently suggested by the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association.5 Both inward wall motion and wall thickening were analyzed. Each segment was assigned a wall motion score of 1 to 4: normal 1, hypokinetic 2 (decreased endocardial excursion and systolic wall thickening), akinetic 3 (absence of endocardial excursion and systolic wall thickening), and dyskinetic 4 (paradoxic outward movement in systole). LV ejection fraction was calculated using automated contour detection. The outlined borders of the LV cavity were manually corrected whenever necessary.6,7 As previously described, papillary muscles were regarded as being part of the LV cavity.7 LV end-diastolic and end-systolic volumes were calculated using slice summation and the LV ejection fraction was derived. For 2-dimensional echocardiography, patients were imaged in the left lateral decubitus position using a commercially available system (Vingmed System FiVe, GE-Vingmed, Milwaukee, Wisconsin). Images were obtained using a 3.5-MHz transducer at a depth of 16 cm in the parasternal and apical views (parasternal longand short-axis, apical 2and 4-chamber views), and saved in cine loop format. Regional wall motion of the 2-dimensional echocardiographic data were evaluated using the same 17-segment model and 4-point grading scale as previously described. LV ejection fraction was calculated From the Departments of Radiology and Cardiology, Leiden University Medical Center, Leiden; and the Department of Epidemiology and Statistics, University Hospital Dijkzigt, Rotterdam, The Netherlands. Dr. Dirksen’s address is: Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. E-mail: M.S.Dirksen@lumc.nl. Manuscript received May 9, 2002; revised manuscript received and accepted July 17, 2002.

To evaluate multi-detector row computed tomographic (CT) depiction of pulmonary veins to provide a road map for radiofrequency catheter ablation.For patients, institutional review board (IRB) approval was not required, and consent was obtained for treatment. Control subjects were part of an IRB-approved research protocol at the institution, in which they had consented to participate. Multi-detector row CT was performed in 23 patients (17 men, six women; mean age, 48 years +/- 11 [standard deviation]) with atrial fibrillation who were admitted for isolation of pulmonary veins by means of radiofrequency catheter ablation. Pulmonary vein anatomy was evaluated, and diameters of pulmonary vein ostia were measured. To determine the shape of ostia, a venous ostium index was calculated for all veins by dividing anterior-posterior measurements by superior-inferior measurements. Results were compared with those in a control group of 11 patients (eight men, three women; mean age, 56 years +/- 11) without atrial fibrillation. Images were evaluated by two observers in consensus.Pulmonary veins additional to the four main veins were found in seven (30%) of 23 patients. Common ostia of left and right pulmonary veins were detected in 19 (83%) and nine (39%) patients, respectively. Early branching occurred more often with right than with left veins (19 [83%] vs three [13%] cases, P.05) in both patients and control subjects. Anterior-posterior diameter of ostia was 12.8 mm +/- 3.3 for left veins, 16.2 mm +/- 3.8 for right veins, and 18.8 mm +/- 7.7 and 28.7 mm +/- 5.1 for left and right common ostia, respectively. Ostia of right pulmonary veins were more round than were ostia of left pulmonary veins (venous ostium index in patients, 0.91 +/- 0.21 vs 0.75 +/- 0.17, P.05; in control subjects, 0.93 +/- 0.12 vs 0.82 +/- 0.17, P.05). The CT data were used to determine ablation strategy and guide catheters during radiofrequency ablation.Multi-detector row CT provides a valuable road map for pulmonary vein anatomy prior to radiofrequency catheter ablation. Variations in number and insertion of pulmonary veins were observed in a considerable number of patients and control subjects.

A 56-year-old man (known to have hypercholesterolemia) was hospitalized with signs of an acute inferior myocardial infarction, as evidenced by typical chest pain lasting for 2 hours and typical ECG changes (ST-T-segment elevation in leads II, III, AvF; no Q-wave formation). Plasma levels of cardiac enzymes (including troponins) were not yet elevated. On the basis of these findings, he was treated by thrombolysis (streptokinase), with relief of chest pain and normalization of ST-T segments. During hospitalization, he experienced an episode of heart failure with dyspnea at rest. Chest x-ray demonstrated pulmonary edema. Treatment with intravenous diuretics and inotropic agents was initiated with adequate response. Resting 2D echocardiography demonstrated an enlarged left ventricle with a resting left ventricular ejection fraction of 35%, …

A 25-year-old female was referred to our clinic withepisodes of palpitations, chest pain and near-collapse.These episodes began during pregnancy and continuedafter delivery. An exercise ECG showed a nonsustainedventricular tachycardia (VT)withrightaxisdeviationandright bundle branch block; similar VTs were inducibleduring electrophysiological testing. Radiofrequencyablation was not possible due to the nonsustainedcharacter of the VTs. The right ventricle appeared normalon contrast ventriculography and arrhythmogenic rightventricular dysplasia was further excluded by 2Dechocardiography using intravenous contrast.X-ray coronary angiography showed an anomalousorigin of the right coronary artery (RCA) from the leftaortic sinus with a separate ostium (Fig. 1). Athero-sclerotic changes were not present. The coronaryangiogram was inconclusive about the exact course ofthe RCA, therefore single breath-hold Multislice SpiralComputed Tomography (MSCT) was performed (Fig. 2).MSCT imaging was performed using a multislice CTscanner (Aquilion, Toshiba Medical Company, Japan)with a rotation time of 0.5sec, 4 detector rows, resultingin a slice thickness of 4 £ 2mm and a reconstructed pitchof 1mm. An intravenous x-ray contrast agent, jobitridol(Xenetixw, Guerbet, Aulnay Sous Bois, France), wasadministered at 3.5–4ml/sec to a total of 160ml. Thetotal radiation exposure was estimated to be 10–13mSv.The MSCT data were processed on a Vitrea workstation(Vital Images, Plymouth, MN). The MSCT scanconfirmed the anomalous origin of the RCA from theleft coronary cusp and revealed an interarterial coursebetween the aorta and pulmonary trunk. This malignantcourse is associated with an increased risk of myocardialinfarction and sudden death.In order to compare MSCT with an establishednoninvasive imaging technique for coronary anomalies,with the patient’s informed consent, coronary MagneticResonance Angiography (MRA) was planned (McCon-nell et al., 1995; Post et al., 1995; Vliegen et al., 1997).According to the protocol described by Stuber et al.(1999), free breathing, navigator-gated 3D coronaryMRA was executed, using a 1.5 T MR scanner

To evaluate in an animal model the potential for clinical use of a new rapid clearance blood pool contrast agent to improve free-breathing and breath-hold magnetic resonance (MR) coronary angiography.Free-breathing and breath-hold MR coronary angiography were performed in a pig model (n = 9) (a) without use of a contrast agent; (b) with P792 (Guerbet Research, Aulnay Sous Bois, France), a monodisperse monogadolinated macromolecular compound that acts as a blood pool contrast agent with rapid clearance properties; and (c) with an extravascular gadolinium-based contrast agent. This resulted in six imaging options, which were compared in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio, and vessel length measurements by using the Student t test.Use of P792 improved CNR and visible vessel length significantly with both MR respiratory motion correction approaches, as compared with nonenhanced MR imaging (P.05). CNR was improved by 76% (from 5.0 to 8.6) with the free-breathing approach and by 34% (from 6.2 to 8.2) with the breath-hold approach. Visible vessel length was increased by 27% (from 79.7 to 99.2 mm) with the free-breathing approach and by 90% (from 48.2 to 86.5 mm) with the breath-hold approach. The P792-enhanced free-breathing approach allowed more distal visualization of the coronary arteries than did the P792-enhanced breath-hold approach (P.05). Use of the extravascular contrast agent did not improve image quality significantly when compared with that of nonenhanced MR images.Use of P792 improves coronary artery MR imaging in conjunction with free-breathing and breath-hold approaches.

A method is proposed for the quantitative assessment of coronary magnetic resonance angiography (MRA) acquisitions. The method is based on four parameters: signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); vessel length; and vessel-edge definition. A pig model (n=7) was used to illustrate the proposed quantitative analysis method. Three-dimensional gradient-echo coronary MRA was performed with and without exogenous contrast enhancement using a gadolinium-based blood-pool contrast agent (Vistarem, Guerbet, Aulnay-Sous-Bois, France). The acquired images could be well differentiated based on the four parameters. The SNR was calculated as 9.0+/-1.4 vs 10.4+/-2.1, the CNR as 6.2+/-0.8 vs 8.2+/-0.9, the vessel length as 48.2+/-11.6 vs 86.5+/-13.8 mm, and the vessel-edge definition as 4.9+/-1.5 vs 7.7+/-3.4. Different coronary MRA techniques can be evaluated objectively with the combined use of SNR, CNR, vessel length, and vessel-edge parameters.

A 66-year-old man presented with typical angina pectoris. The angina was exercise related and had developed in the past few weeks. Treadmill exercise testing induced the angina but did not reveal signs of ischemia on the ECG. Technetium myocardial perfusion scintigraphy showed a minor perfusion defect in the inferoposterior wall (Figure 1). Coronary catheterization showed the left main, left anterior descending, and left circumflex arteries without clinically significant stenoses. The origin of the right coronary artery (RCA), however, could not be engaged, preventing selective visualization. Distally, the RCA showed retrograde filling. A second catheterization effort …