Feasibility of Quantification of Intracranial Aneurysm Pulsation with 4D CTA with Manual and Computer-Aided Post-Processing

<div><p>Background and Purpose</p><p>The analysis of the pulsation of unruptured intracranial aneurysms might improve the assessment of their stability and risk of rupture. Pulsations can easily be concealed due to the small movements of the aneurysm wall, making post-processing highly demanding. We hypothesized that the quantification of aneurysm pulsation is technically feasible and can be improved by computer-aided post-processing.</p><p>Materials and Methods</p><p>Images of 14 cerebral aneurysms were acquired with an ECG-triggered 4D CTA. Aneurysms were post-processed manually and computer-aided on a 3D model. Volume curves and random noise-curves were compared with the arterial pulse wave and volume curves were compared between both post-processing modalities.</p><p>Results</p><p>The aneurysm volume curves showed higher similarity with the pulse wave than the random curves (Hausdorff-distances 0.12 vs 0.25, p<0.01). Both post-processing methods did not differ in intra- (r = 0.45 vs r = 0.54, p>0.05) and inter-observer (r = 0.45 vs r = 0.54, p>0.05) reliability. Time needed for segmentation was significantly reduced in the computer-aided group (3.9 ± 1.8 min vs 20.8 ± 7.8 min, p<0.01).</p><p>Conclusion</p><p>Our results show pulsatile changes in a subset of the studied aneurysms with the final prove of underlying volume changes remaining unsettled. Semi-automatic post-processing significantly reduces post-processing time but cannot yet replace manual segmentation.</p></div

Aneurysm characteristics.

<p>Aneurysm characteristics.</p

Relative volume changes of all 14 aneurysms with manual segmentation.

<p>Aneurysms 1, 2, 5, and 8 show a pulsation-like profile. Plot number 15 shows the cumulative pulsation of all aneurysms.</p

Results of the intraobserver (mean±LOA -0.02 ± 0.11 vs. 0.01 ± 0.11, upper row) and interobserver agreements (mean±LOA 0.007 ± 0.11 vs. -0.01 ± 0.12 lower row) for the 2D post-processing (right) and 3D+t post-processing (left).

<p>Results of the intraobserver (mean±LOA -0.02 ± 0.11 vs. 0.01 ± 0.11, upper row) and interobserver agreements (mean±LOA 0.007 ± 0.11 vs. -0.01 ± 0.12 lower row) for the 2D post-processing (right) and 3D+t post-processing (left).</p

Boxplots of Hausdorff distances between the volume curves and random curves and the pulse wave on the right and left-hand side (0.12 vs 0.25, p<0.01).

<p>Boxplots of Hausdorff distances between the volume curves and random curves and the pulse wave on the right and left-hand side (0.12 vs 0.25, p<0.01).</p

Workflow on the 3D+t model: On axial images the vasculature is defined with a threshold (green).

<p>To reduce computation time for the 3D+t model, the volume for post-processing is reduced by placing a VOI over the aneurysm (A). The resulting 3D+t model can be rotated, translated and zoomed (B). Segmentation points are placed on the aneurysms neck (C) and the aneurysm (green) is separated from the parent vessel (red) and the volume and surface is calculated (D).</p

Acute impact of an endurance race on biventricular and biatrial myocardial strain in competitive male and female triathletes evaluated by feature-tracking CMR

Objectives!#!Cardiac adaptation in endurance athletes is a well-known phenomenon, but the acute impact of strenuous exercise is rarely reported on. The aim of this study was to analyze the alterations in biventricular and biatrial function in triathletes after an endurance race using novel feature-tracking cardiac magnetic resonance (FT-CMR).!##!Methods!#!Fifty consecutive triathletes (45 ± 10 years; 80% men) and twenty-eight controls were prospectively recruited, and underwent 1.5-T CMR. Biventricular and biatrial volumes, left ventricular ejection fraction (LVEF), FT-CMR analysis, and late gadolinium imaging (LGE) were performed. Global systolic longitudinal (GLS), circumferential (GCS), and radial strain (GRS) were assessed. CMR was performed at baseline and following an endurance race. High-sensitive troponin T and NT-proBNP were determined. The time interval between race completion and CMR was 2.3 ± 1.1 h (range 1-5 h).!##!Results!#!Post-race troponin T (p &amp;lt; 0.0001) and NT-proBNP (p &amp;lt; 0.0001) were elevated. LVEF remained constant (62 ± 6 vs. 63 ± 7%, p = 0.607). Post-race LV GLS decreased by tendency (- 18 ± 2 vs. - 17 ± 2%, p = 0.054), whereas GCS (- 16 ± 4 vs. - 18 ± 4%, p &amp;lt; 0.05) and GRS increased (39 ± 11 vs. 44 ± 11%, p &amp;lt; 0.01). Post-race right ventricular GLS (- 19 ± 3 vs. - 19 ± 3%, p = 0.668) remained constant and GCS increased (- 7 ± 2 vs. - 8 ± 3%, p &amp;lt; 0.001). Post-race left atrial GLS (30 ± 8 vs. 24 ± 6%, p &amp;lt; 0.0001) decreased while right atrial GLS remained constant (25 ± 6 vs. 24 ± 6%, p = 0.519).!##!Conclusions!#!The different alterations of post-race biventricular and biatrial strain might constitute an intrinsic compensatory mechanism following an acute bout of endurance exercise. The combined use of strain parameters may allow a better characterization of ventricular and atrial function in endurance athletes.!##!Key points!#!• Triathletes demonstrate a decrease of LV global longitudinal strain by tendency and constant RV global longitudinal strain following an endurance race. • Post-race LV and RV global circumferential and radial strains increase, possibly indicating a compensatory mechanism after an acute endurance exercise bout. • Subgroup analyses of male triathletes with focal myocardial fibrosis did not demonstrate alterations in biventricular and biatrial strain after an endurance race