Multisegment and halfscan reconstruction of 16-slice computed tomography for assessment of regional and global left ventricular myocardial function.
ABSTRACT We sought to prospectively compare multisegment and halfscan reconstruction of 16-slice computed tomography (CT) for the assessment of regional and global left ventricular myocardial function with magnetic resonance imaging (MRI) as the reference standard.
Forty-two patients underwent CT with 16 x 0.5-mm detector collimation. Electrocardiogram-gated reconstructions were generated with multisegment reconstruction (using up to 4 segments correlated with the raw data of up to 4 heartbeats) and standard halfscan reconstruction. Steady-state free-precession cine MRI was acquired within 24 hours.
More normal myocardial segments were identified correctly with multisegment (95%, 620/656) compared with halfscan reconstruction (88%, 582/656) of CT (P < 0.001). Also, the accuracy (92% [657/714] vs. 87% [620/714]) and rate of nondiagnostic segments (0% vs. 5% [33/714]) were significantly better when using multisegment reconstruction (P < 0.001). The image quality with multisegment reconstruction was significantly superior to that achieved with halfscan reconstruction (P < 0.001). In the assessment of global left ventricular function, multisegment and halfscan reconstruction of CT showed high correlations for all parameters with MRI, whereas Bland-Altman analysis revealed smaller limits of agreement for assessment of myocardial mass with multisegment reconstruction (P = 0.025), but no significant differences between both reconstruction techniques in the measurement of left ventricular volumes as compared with MRI.
Multisegment reconstruction of 16-detector row CT improves image quality and assessment of regional wall motion compared with standard halfscan reconstruction.
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ABSTRACT: OBJECTIVE: To evaluate the effect of a temporal resolution improvement method (TRIM) for cardiac CT on diagnostic image quality for coronary artery assessment. MATERIALS AND METHODS: The TRIM-algorithm employs an iterative approach to reconstruct images from less than 180° of projections and uses a histogram constraint to prevent the occurrence of limited-angle artifacts. This algorithm was applied in 11 obese patients (7 men, 67.2±9.8 years) who had undergone second generation dual-source cardiac CT with 120kV, 175-426mAs, and 500ms gantry rotation. All data were reconstructed with a temporal resolution of 250ms using traditional filtered-back projection (FBP) and of 200ms using the TRIM-algorithm. Contrast attenuation and contrast-to-noise-ratio (CNR) were measured in the ascending aorta. The presence and severity of coronary motion artifacts was rated on a 4-point Likert scale. RESULTS: All scans were considered of diagnostic quality. Mean BMI was 36±3.6kg/m(2). Average heart rate was 60±9bpm. Mean effective dose was 13.5±4.6mSv. When comparing FBP- and TRIM reconstructed series, the attenuation within the ascending aorta (392±70.7 vs. 396.8±70.1HU, p>0.05) and CNR (13.2±3.2 vs. 11.7±3.1, p>0.05) were not significantly different. A total of 110 coronary segments were evaluated. All studies were deemed diagnostic; however, there was a significant (p<0.05) difference in the severity score distribution of coronary motion artifacts between FBP (median=2.5) and TRIM (median=2.0) reconstructions. CONCLUSION: The algorithm evaluated here delivers diagnostic imaging quality of the coronary arteries despite 500ms gantry rotation. Possible applications include improvement of cardiac imaging on slower gantry rotation systems or mitigation of the trade-off between temporal resolution and CNR in obese patients.European journal of radiology 11/2012; · 2.65 Impact Factor
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ABSTRACT: This study was designed to compare the accuracy of 64-row contrast computed tomography (CT), invasive cineventriculography (CVG), 2-dimensional echocardiography (2D Echo), and 3-dimensional echocardiography (3D Echo) for left ventricular (LV) function assessment with magnetic resonance imaging (MRI). Cardiac function is an important determinant of therapy and is a major predictor for long-term survival in patients with coronary artery disease. A number of methods are available for assessment of function, but there are limited data on the comparison between these multiple methods in the same patients. A total of 36 patients prospectively underwent 64-row CT, CVG, 2D Echo, 3D Echo, and MRI (as the reference standard). Global and regional LV wall motion and ejection fraction (EF) were measured. In addition, assessment of interobserver agreement was performed. For the global EF, Bland-Altman analysis showed significantly higher agreement between CT and MRI (p < 0.005, 95% confidence interval: ±14.2%) than for CVG (±20.2%) and 3D Echo (±21.2%). Only CVG (59.5 ± 13.9%, p = 0.03) significantly overestimated EF in comparison with MRI (55.6 ± 16.0%). CT showed significantly better agreement for stroke volume than 2D Echo, 3D Echo, and CVG. In comparison with MRI, CVG-but not CT-significantly overestimated the end-diastolic volume (p < 0.001), whereas 2D Echo and 3D Echo significantly underestimated the EDV (p < 0.05). There was no significant difference in diagnostic accuracy (range: 76% to 88%) for regional LV function assessment between the 4 methods when compared with MRI. Interobserver agreement for EF showed high intraclass correlation for 64-row CT, MRI, 2D Echo, and 3D Echo (intraclass correlation coefficient >0.8), whereas agreement was lower for CVG (intraclass correlation coefficient = 0.58). 64-row CT may be more accurate than CVG, 2D Echo, and 3D Echo in comparison with MRI as the reference standard for assessment of global LV function.Journal of the American College of Cardiology 05/2012; 59(21):1897-907. · 14.09 Impact Factor