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Blood velocities measured by Transcranial Doppler (TCD) are dependent on the angle between the incident ultrasound beam and the direction of blood flow (known as the Doppler angle). However, when TCD examinations are performed without imaging the Doppler angle for each vessel segment is not known. We have measured Doppler angles in the basal cerebral arteries examined with TCD using three-dimensional (3D) vessel models generated from computed tomography angiography (CTA) scans. This approach produces angle statistics that are not accessible during non-imaging TCD studies. We created 3D models of the basal cerebral arteries for 24 vasospasm patients. Standard acoustic windows were mapped to the specific anatomy of each patient. Virtual ultrasound transmit beams were generated that originated from the acoustic window and intersected the centerline of each arterial segment. Doppler angle measurements were calculated and compiled for each vessel segment. Doppler angles were smallest for the middle cerebral artery M1 segment (median 24.6°) and ophthalmic artery (median 25.0°), and largest for the anterior cerebral artery A2 segment (median 76.4°) and posterior cerebral artery P2 segment (median 75.8°). The ophthalmic artery had the highest proportion of Doppler angles that were less than 60° (99%) while the anterior cerebral artery A2 segment had the lowest proportion of Doppler angles that were less than 60° (10%). These angle measurements indicate the expected deviation between measured and true velocities in the cerebral arteries, highlighting specific segments that may be prone to underestimation of velocity.

Right ventricular (RV) failure is a key determinant of morbidity and mortality in pulmonary hypertension (PH). The present study aims to add to existing descriptions of RV structural and functional changes in PH through a comprehensive three-dimensional (3D) shape analysis. We performed 3D echocardiography on 53 subjects with PH and 19 normal subjects. Twenty short-axis slices from apex to tricuspid centroid were measured to characterize regional shape: apical angle, basal bulge, eccentricity, and area. Transverse shortening was assessed by fractional area change (FAC) in each short-axis slice, longitudinal contraction was assessed by tricuspid annular plane systolic excursion (TAPSE) and global function by RV ejection fraction. Multivariate logistic analysis was used to compare the association of RV parameters with New York Heart Association (NYHA) class. Compared to normal, RV function in PH is characterized by decreased stroke volume index (SVi), fractional area change and ejection fraction. Increased eccentricity, apical rounding and bulging at the base characterize the shape of the RV in PH. Increased SVi, ejection fraction and mid-ventricular FAC were associated with less severe NYHA class in adjusted analyses. The RV in idiopathic PH (iPAH) was observed to have a larger end-diastolic volume and decreased function compared with connective tissue disease associated PH (ctd-PH). This work describes increased eccentricity and decreased systolic function in subjects with PH. Functional parameters were associated with NYHA class and heterogeneity in the phenotype was noted between subjects with iPAH and ctd-PH.

In patients with transposition of the great arteries corrected by interatrial baffle (TGA) and those with congenitally corrected transposition of the great arteries (ccTGA) the right ventricle (RV) is subjected to systemic pressure and fails prematurely. Previous studies have demonstrated RV dysfunction may be more pronounced in patients with TGA. The present study sought to compare patients with TGA and ccTGA using three-dimensional (3D) techniques to comprehensively analyze the shape, volume, global and regional function in the systemic RV. We compared RV size, shape, and regional and global function in 25 patients with TGA, 17 patients with ccTGA, and 9 normal subjects. The RVs were reconstructed from cardiac Magnetic Resonance Images for 3D analyses. Compared to normal, the RV in TGA and ccTGA was dilated, rounded, and reduced in function. Compared to each other, TGA and ccTGA patients had similar RV size and shape. Global RV function was lower in TGA than ccTGA when assessed from ejection fraction (EF) (30 ± 7 vs. 35 ± 7, p = 0.02) and from normalized tricuspid annular systolic plane excursion (TAPSE) (0.10 ± 0.04 vs. 0.18 ± 0.04, p < 0.01). Basilar RV function was poorer in the TGA patients when compared to ccTGA. The systemic RVs in both TGA and ccTGA are dilated, spherical, and poorly functioning. Compared to ccTGA, TGA RVs have reduced TAPSE and worse basilar hypokinesis.

We observed an abnormal contraction pattern in the right ventricle (RV) in postoperative tetralogy of Fallot (TOF) patients when measuring the regional contribution to global stroke volume (rSV) of 20 RV slices from apex to base. We compared the rSV method’s performance with the centersurface method which offers greater flexibility in defining regions of interest. We reconstructed the RV in 3D from manually traced borders in 20 repaired TOF patients and nine normal subjects from cardiac magnetic resonance images. Wall motion was measured as the local orthogonal distance between the RV endocardium at end diastole and end systole. The RV was divided into septum, conus, and 10 free wall regions. For comparison with the rSV method the free wall regions were grouped into apical, mid, and basal levels. The RV was also divided into two other 3-part models for comparison. Both rSV and centersurface methods showed that TOF patients have diminished function at the base and increased function at the apex compared to normal. The other 3-part models were less informative because large region size obscured local function abnormalities. Septal and free wall motion differed between the groups. Two analysis methods agreed that patients with TOF have a pattern of relatively increased wall motion at the apex and diminished function at the base compared to normal. The centersurface analysis showed that characterization of the RV’s complex pattern of regional function requires more than three RV subdivisions.

The correlation between right ventricular ejection fraction (RVEF) and tricuspid annular plane systolic excursion (TAPSE) by two-dimensional (2-D) echo has been repeatedly validated, but not by magnetic resonance imaging (MRI) nor in patients with congenital heart disease. We tested whether TAPSE measurements by MRI correlate with RVEF in surgically repaired tetralogy of Fallot (TOF) patients. TAPSE was measured from systolic displacement of the RV-freewall/tricuspid annular plane junction in the apical 4-chamber view in 7 normal subjects and 14 TOF patients. The RV was reconstructed in 3-D from manually traced borders on MR images to compute true EF. Because we previously observed discrepancy between TAPSE and RVEF in the presence of regional dysfunction, we also analyzed RV wall motion in terms of regional stroke volume at 20 short axis slices from apex to tricuspid annulus. RVEF was 52 ± 3% in normal subjects and 41 ± 9% in TOF ( P  < 0.01). TAPSE correlated weakly ( r  = 0.50, P  < 0.05) with RVEF. TOF patients exhibited increased regional stroke volume from apical portions of the RV and decreased regional stroke volume at the base compared to normal ( P  < 0.05 at 15 of 20 slices). Regional stroke volume in apical slices correlated inversely with RVEF such that patients with higher apical stroke volume had lower RVEF ( P  < 0.05). TAPSE is not a reliable measure of RVEF in TOF by MRI. TAPSE may be of limited use in conditions that exhibit abnormal regional contraction.

For reproducible measurements of right ventricular (RV) volume and function, it may be important to use a consistent method to identify end systole (ES). We determined whether a significant difference exists between RV volumes measured using varying criteria from previous studies to define the timing of ES. In three normal subjects and nine patients with congenital heart disease, we measured RV volume from 3D reconstructions generated from 12 short and long axis magnetic resonance images (MRI). Cine frames analyzed included two frames before and three frames following ES, which we determined as the frame in which chamber area was most frequently minimum. ES coincided with onset of aortic valve closure in ten of 12 subjects; complete closure occurred 1 frame later. The tricuspid valve began to open 1–2 frames after ES, and completely opened 2–4 frames after ES. RV volume was unchanged between ES and the frame following. However, ES volume differed significantly from volume measured 1 or 2 frames before ES and from volume measured 2 or 3 frames following ES, although these volume differences lay within the range of observer variability. The time of minimum RV area in the 4-chamber view agreed closely with that of ES (intraclass correlation coefficient = 0.962). We conclude that minimum RV area in the 4-chamber view is a convenient marker of use for ES, and that aortic valve closure or onset of tricuspid valve opening could also be used, being unlikely to result in clinically significant errors.

We sought to determine which of the three orientations is the most reliable and accurate for quantifying right ventricular (RV) volume and ejection fraction (EF) by cardiac magnetic resonance using Simpson’s method. We studied 20 patients using short axis (SA), transaxial (TA), and horizontal long axis (HLA) orientations. Three readers independently traced RV endocardial contours at end-diastole and end-systole for each orientation. End-diastolic volumes (EDVs), end-systolic volumes (ESVs), and EF were calculated and compared with the 3D piecewise smooth subdivision surface (PSSS) method. The intraclass correlation coefficients among the 3 readers for EDV, ESV, and EF were 0.92, 0.82, and 0.42, respectively, for SA, 0.95, 0.92, and 0.67 for TA, and 0.85, 0.93, and 0.69 for HLA. For mean data there was no significant difference between TA and PSSS for EDV (−2.6%, 95% CI: −8.2 to 3.3%), ESV (−5.9%, −15.2 to 4.5%), and EF (1.7%, −1.5 to 4.9%). HLA was accurate for ESV (−8.9%, −18.5 to 1.8%) and EF (−0.7%, −3.8 to 2.5%) but significantly underestimated EDV (−9.8, −16.6 to −2.4%). SA was accurate for EDV (0.5%, −6.0 to 7.5%) but overestimated ESV (10.5%, 0.1 to 21.9%) and had poor interrater reliability for EF. Conclusions. The TA orientation provides the most reliable and accurate measures of EDV, ESV, and EF.

Three-dimensional (3D) echocardiography has been shown to offer highly accurate measurements of left ventricular (LV) volume and mass. The present study evaluated the accuracy of 3D surface reconstruction by the piecewise smooth subdivision method in measuring volume and mass not only in the LV but also in the more complexly shaped right ventricle (RV). 3D echo scans were obtained of in vitro LV's (n = 15) and RVs (n = 10). From digitized images, ventricular borders were traced and used in surface reconstructions. Mass and volume determined from the reconstructions were compared to true volume and mass determined prior to imaging. Additionally casts of two RVs were made and laser-scanned. Distances between the laser-identified points on the RV surface and the corresponding 3D echo reconstructions were measured. 3D LV volume agreed well with the true volume (y = 0.99x + 1.73, r = 0.99, SEE = 3.35 ml, p < 0.0001), as did 3D LV mass (y = 0.99x - 4.71, r = 0.99, SEE = 9.85 g, p < 0.0001). 3D RV volume overestimated true volume (y = 1.11x + 1.77, r = 0.99, SEE = 3.36 ml, p < 0.001) by 6.23+/-3.70 ml (p < 0.0001). 3D mass agreed well with RV mass (y = 0.78x + 17.32, r2 = 0.93, SEE = 3.54 g, p < 0.0001). 3D echo reconstructions matched the laser-scanned RV closely with residual distances of 1.1+/-0.9 and 1.4+/-1.2 mm, respectively. 3D echo using freehand scanning combined with surface reconstruction by the piecewise smooth subdivision surface method enables accurate determination of LV mass and volume, of RV mass and volume, and of the RV's complex shape.