(A) Analysis based on the volumetric threshold method is illustrated. From left to right, end-diastolic images are displayed in short-axis, 4-chamber, and 2-chamber views. The left ventricular end-diastolic volume is semi-automatically derived. (B) An example of left ventricular ejection fraction (LVEF) assessment based on the Simpson method is provided. Endocardial contours are drawn on reconstructed short-axis slices to calculate volumes and subsequently LVEF. MDCT = multidetector row computed tomography.

(A) Short-axis reconstruction in end diastole. (B) Short-axis reconstruction in end systole. Akinesia and thinning of the myocardium is observed in the lateral wall (black arrows). In addition, hypoattenuation (dark endocardial rim) corresponding to previous myocardial infarction is present in this region. Quantification of left ventricular volumes reveals severely reduced left ventricular systolic function (LVEF 28%). Abbreviations as in Figure 1.

This reconstructed long-axis view clearly shows how the anatomy of the mitral valve and the subvalvular apparatus can be assessed. In the diastolic phase, the mitral valve leaflet (open arrow), the tendinous cords (solid arrow), and the papillary muscles (PM) are well visualized. Ao = aorta; LV = left ventricle; MDCT = multidetector row computed tomography.

In this patient, a bicuspid aortic valve is demonstrated with contrast-enhanced multidetector row computed tomography (MDCT) (left panel). The extent and location of calcifications (white arrows) can be well visualized with MDCT and correlate well with the findings during cardiac surgery (right panel).

With the use of 3D volume rendered reconstructions, the anatomy of the coronary venous system and the relation between the coronary sinus (CS) and the mitral valve annulus can be assessed. In this patient, the CS courses along the posterior wall of the left atrium (LA), rather than along the mitral valve annulus. In patients with a large distance between the CS and the mitral annulus (indicated by the white arrow), a percutaneous mitral annuloplasty may not be feasible. GCV = great cardiac vein; LMV = left marginal vein; PIV = posterior interventricular vein; PVLV = posterior vein of the left ventricle.

Three-dimensional volume-rendered reconstructions of 64-slice MDCT scans to illustrate pulmonary vein anatomy. (A) Normal pulmonary vein anatomy is shown. Four pulmonary veins with separate insertions in the left atrium (LA) are present. (B to D) Variations in pulmonary vein anatomy. (B) A common ostium of the left-sided pulmonary veins is shown (arrows). (C) An additional right-sided pulmonary vein (arrow). (D) An aberrant insertion of the additional pulmonary vein is present (arrow). All of these anatomical variations in pulmonary vein anatomy may likely impact catheter ablation procedures. LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; MDCT = multidetector row computed tomography; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.

The process of image integration consists of several steps. First, multidetector row computed tomography (MDCT) scanning is performed (left panel). With the use of dedicated algorithms based on setting intensity levels for Hounsfield units, the MDCT scan is segmented into different structures (middle panel). During the catheter ablation procedure, the segmented left atrium is aligned with the reconstructed electroanatomical map (registration). Finally, the actual ablation can be performed guided by the anatomy of the left atrium and pulmonary veins (right panel). Based on the real anatomy derived from the MDCT scan, the radiofrequency lesions (represented by the red dots, right panel) can be targeted around the pulmonary veins.

This patient has a persistent left superior vena cava (LSVC) and a markedly enlarged coronary sinus and great cardiac vein (GCV). The upper panel shows a 3-dimensional volume-rendered reconstruction, illustrating the LSVC and coronary venous system. The lower panels show multiplanar reformatted images, where the target vein (posterolateral branch) for left ventricular lead implantation is identified (arrows). Left ventricular lead implantation for cardiac resynchronization therapy (CRT) is significantly more complicated in patients like these. A noninvasive pre-procedure evaluation with multidetector row computed tomography for elucidation of the "road map" can be very helpful.

With the use of 64-slice multidetector row computed tomography, the prevalence of the PIV, PVLV, and LMV was assessed in 28 normal control patients, 38 patients with coronary artery disease (CAD), and 34 patients with a history of myocardial infarction. The LMV was less frequently identified in patients with a history of myocardial infarction as compared with CAD patients and control patients (27% vs. 61% and 71%, respectively). This may hamper left ventricular lead positioning in case of CRT. *p < 0.01. **p < 0.0001. Abbreviations as in Figure 5. Adapted from Van de Veire et al. (62).

Examples of the left (left panel) and right (right panel) pericardiophrenic bundles as shown with 64-slice multidetector row computed tomography (MDCT). The yellow arrows indicate the course of the neurovascular bundles.

(A) A 3-dimensional volume-rendered reconstruction demonstrates the left pericardiophrenic bundle (LPCB), representing the left phrenic nerve. The course of the LPCB is indicated by white and yellow arrows. (B) The same view as in (A), after adjustment of the window level. The course of the LPCB is again represented by yellow arrows. In this reconstruction, the GCV and the lateral marginal branch (white arrow) are well visualized. Consequently, the relationship between the phrenic nerve and the cardiac veins can be well appreciated. (C) An occlusive venogram of the coronary sinus. The tortuous lateral marginal branch (white arrow) is clearly visualized. A good correlation with the noninvasive evaluation by MDCT (B) is seen. This vein was chosen as the target branch because it was not seen to intersect the course of the LPCB. (D) A unipolar lead placed in the target vein (white arrows). High-output pacing from the lead during the procedure did not reveal any diaphragmatic capture. Abbreviations as in Figures 3 and 5.