Long-Term Volumetric Evaluation of Stent-Assisted Balloon-Induced Intimal Disruption and Relamination of Aortic Dissection (STABILISE) in Acute Type B Aortic Dissection.

BACKGROUND: To quantify the volumetric aortic remodeling of patients with acute type B aortic dissection treated with the stent-assisted balloon-induced intimal disruption and relamination (STABILISE) technique. METHODS: All patients with acute type B aortic dissection operated with the STABILISE technique between 2014 and 2017 with preoperative, postoperative, and >12 months (follow-up) computed tomography scans were included in this study. True lumen and total aortic volume were accurately assessed in the thoracic and abdominal portions with a semiautomatic three-dimensional tool. Associations with long-term adverse events were estimated. RESULTS: Seventeen patients were measured at preoperative, postoperative, and a mean follow-up of 19 ± 8 months. The false lumen to total volume ratio decreased on average from 63% to 18% after STABILISE (P < 0.001) and remained around 12% at follow-up. These remodeling was more pronounced in the thoracic aorta (7%) than in the abdominal aorta (28%). The trend in aortic size growth was stronger for volumes than for maximum areas or diameters (P < 0.001, P < 0.05, and P < 0.05, respectively). Adverse events were identified in 4 patients during a long-term follow-up of 76 ± 18 months. The only aortic size variable assessed preoperatively that was associated with undesirable events was the total volume of the abdominal aorta (P < 0.05). CONCLUSIONS: A volumetric analysis of dissected aortic size after the STABILISE procedure allowed accurate quantification of mid-term aortic remodeling and helped to identify the abdominal aortic volume as a preoperative variable associated with undesirable long-term events.

Eleven Years After Scimitar Syndrome Repair With the Lugones Technique: Usefulness of Four-Dimensional Flow Magnetic Resonance Imaging.

Anatomic and physiologic assessment of surgical repair of scimitar syndrome can be challenging. We evaluated the first patient who underwent the Lugones procedure in 2012 using 4D flow magnetic resonance imaging. With this technology, we demonstrate that the reconstructed right pulmonary venous return drains into the left atrium with laminar flow, just as normal pulmonary veins do.

Morphological and dynamic analysis of the normal aortic valve with 4D computed tomography.

OBJECTIVES: To evaluate the precise dimensions of the normal aortic root, especially the true aortic annulus, during the cardiac cycle using an innovative reconstruction method based on multiphase cardiac computed tomography and to assess the feasibility and the reproducibility of this method for aortic root analysis. METHODS: Between January 2019 and June 2021, 30 optimal consecutive ECG-gated multiphase cardiac computed tomography of patients with normal tricuspid aortic valve were analysed using an in-house software. Aortic annulus border was pinpointed on 9 reconstructed planes and the 3D coordinates of the 18 consecutive points were interpolated into a 3D curve using a cubic spline. Three additional planes were generated at the level of the left ventricular outflow tract, the level of the Valsalva sinus and the level of the sinotubular junction. This procedure was repeated for all the 10 temporal phases of the RR interval. RESULTS: The aortic annulus mean 3D and 2D areas were 7.67 ± 1.51 and 5.16 ± 1.40 cm2, respectively. The mean 2D diameter was 2.51 ± 0.23 cm. The mean global area expansion was 11.8 ± 3.5% and the mean perimeter expansion of 7.1 ± 2.6%. During the cardiac cycle, the left ventricle outflow tract expands, reaching its maximum surface at the end of diastole, followed by the aortic annulus, the Valsalva sinuses and the sinotubular junction. The aorta changes from a clover-shaped cone during diastole to more cylindrical shape during systole. Compared to the 3D measurements, the analysis of the virtual basal ring significantly underestimates the annulus area, perimeter, and mean diameter. CONCLUSIONS: 4D morphometric analysis enables to have a precise and reproducible evaluation of the aortic annulus. The aortic annulus and root are deformable structures that undergo a unique expansion sequence during the cardiac cycle which should be considered for procedural planning.

Abdominal aortic calcium and geometry in patients with essential hypertension.

PURPOSE: Abdominal aorta calcium (AAC) burden and dilatation are associated with an increased risk of mortality. The purpose of this study was to investigate determinants of AAC and abdominal aorta size in patients with essential hypertension. MATERIALS AND METHODS: Patients with uncomplicated essential hypertension who had undergone non-enhanced abdominal CT to rule out secondary hypertension in addition to biological test were recruited between 2010 and 2018. A semi-automatic system was designed to estimate the aortic size (diameter, length, volume) and quantify the AAC from mesenteric artery to bifurcation using the Agatston score. Determinants of aortic size and those related to AAC were searched for using uni- and multivariables analyses. RESULTS: Among 293 randomly selected patients with hypertension (age 52 ± 11 [SD] years) included, 23% had resistant hypertension. Mean abdominal aorta diameter was 20.1 ± 2.1 (SD) mm. Eight (3%) patients had abdominal aorta aneurysm ≥ 30 mm and 58 (20%) had dilated abdominal aorta ≥ 27 mm. Median AAC score was 38 and calcifications were detected in the infra- and supra-renal abdominal aortic portions in 59% and 26% of the patients, respectively. After adjustment for age, male sex and body surface area, abdominal aorta diameter was positively associated with diastolic blood pressure (P = 0.0019). Smoking was the single variable associated with calcified abdominal aorta (P < 0.001) after adjustment for cofactors. In patients with calcifications of abdominal aorta, the score increased with smoking history (P < 0.001), statins treatment (P < 0.01), greater number of anti-hypertensive drugs (P < 0.01), larger abdominal aorta (P < 0.05) and greater systolic blood pressure (P < 0.05). Patients with resistant hypertension had more AAC in the supra-renal abdominal aorta portion than those without resistant hypertension (P < 0.01). CONCLUSION: In patients with essential hypertension, abdominal aorta dilation is related with diastolic blood pressure while AAC is associated with smoking history and resistant hypertension when located to the supra-renal abdominal aorta portion.

Discordance between 2D and 4D flow in the assessment of pulmonary regurgitation severity: a right ventricular remodeling follow-up study.

OBJECTIVES: Pulmonary regurgitation (PR) is common in adult congenital heart disease (ACHD). 2D phase contrast MRI is the reference method for the quantification of PR and helps in the decision of pulmonary valve replacement (PVR). 4D flow MRI can be an alternative method to estimate PR but more validation is still needed. Our purpose was to compare 2D and 4D flow in PR quantification using the degree of right ventricular remodeling after PVR as the reference standard. METHODS: In 30 adult patients with a pulmonary valve disease recruited between 2015 and 2018, PR was assessed using both 2D and 4D flow. Based on the clinical standard of care, 22 underwent PVR. The pre PVR estimate of PR was compared using the post-operative decrease in right ventricle end-diastolic volume on follow-up exam as reference. RESULTS: In the overall cohort, regurgitant volume (Rvol) and regurgitant fraction (RF) of PR measured by 2D and 4D flow were well correlated but with moderate agreement in the overall cohort (r = 0.90, mean diff. -14 ± 12.5 mL; and r = 0.72, mean diff. -15 ± 13%; all p < 0.0001). Correlations between Rvol estimates and right ventricle end-diastolic volume decrease after PVR was higher with 4D flow (r = 0.80, p < 0.0001) than with 2D flow (r = 0.72, p < 0.0001). CONCLUSIONS: In ACHD, PR quantification from 4D flow better predicts post-PVR right ventricle remodeling than that from 2D flow. Further studies are needed to evaluate the added value of this 4D flow quantification for guiding replacement decision. KEY POINTS: • Using 4D flow MRI allows a better quantification of pulmonary regurgitation in adult congenital heart disease than 2D flow when taking right ventricle remodeling after pulmonary valve replacement as a reference. • A plane positioned perpendicular to the ejected flow volume as allowed by 4D flow provides better results to estimate pulmonary regurgitation.

Volumetric Analysis of Progressive Remodeling of Isolated Mesenteric Artery Dissection Treated by Conservative Therapy.

PURPOSE: To characterize remodeling of conservatively treated isolated mesenteric artery dissection (IMAD) using 3-dimensional (3D) volumetric analysis. MATERIAL AND METHODS: Patients with Type I/II (classification of Yun) treated by conservative therapy between January 2018 and January 2020 were prospectively included. Semiautomatic morphological analysis of the superior mesenteric artery (SMA) included volumetric measurements of the true lumen (TL), false lumen (FL), and overall lumen (OL) and 3D aortomesenteric angles from computed tomography angiography data at admission (T0), 1 month (T1), and 12 months (T12). The SMA morphology of patients with IMAD (n = 15, mean age 53 years ± 7; 87% men) was also compared with that of control individuals (n = 51, mean age 56 years ± 4; 94% men). RESULTS: A significant reduction in OL volume was observed (P <.001), whereas TL volume remained stable (P =.23). The TL/OL volume ratio significantly increased over time (P =.001) from 53% at T1 to 78% at T12. Aortomesenteric 3D angles at 2, 4, and 6 cm from the ostium showed a progressive decrease toward values observed in the control group (P =.013, P =.002, and P =.027, respectively). At T12, 5 patients (33%) had complete remodeling, and aneurysmal change was observed in 2 patients (<20 mm). Smoking and SMA angle at a distance of 6 cm from the ostium (T0) were the only factors affecting remodeling negatively at T12. CONCLUSIONS: One-year remodeling in IMAD followed an overall decrease in OL volume related to a decrease in FL volume. Smokers and patients with larger SMA angles at baseline showed poorer remodeling. Spontaneous arterial remodeling in IMAD might favor conservative therapy.

Computed tomographic analysis of the morphometrics and dynamics of the tricuspid annulus in secondary functional tricuspid regurgitation.

Objectives: Secondary functional tricuspid regurgitation (FTR) management remains controversial mainly due to the lack of knowledge in its pathogenesis and the difficulties to measure the actual dimensions of tricuspid annulus (TA) with current imaging methods. Using a novel method based on multiphase cardiac computed tomography (CT) scan acquisition to accurately analyze the right atrioventricular junction size, we sought to explore modifications of TA morphometry and dynamics in secondary FTR. Methods: Echocardiographic and cardiac CT studies were obtained from 21 patients with severe mitral regurgitation (MR group) and 21 patients with dilated cardiomyopathy (DCMP group). Using an in-house software, a 3-dimensiontal (3D) semiautomated delineation of the TA perimeter was assessed. Modifications of diameters, 2-dimensional/3D areas and perimeters were analyzed through time. These 2 groups of patients were compared with 30 healthy subjects, considering the presence of a significant (≥2+) versus nonsignificant (<2+) FTR in each group. Results: Maximum TA 3D areas were 7.0 ± 1.2 cm2/m2 in healthy subjects at mid-to-late diastole and were smaller than in the MR group (9.8 ± 2.1 cm2/m2, P < .001) and the DCMP group (9.2 ± 3.0 cm2/m2, P < .001). In the MR group, patients with FTR <2+ had also larger TA areas and diameters than healthy patients (P < .01 for all 3D/2-dimensional parameters). TA shape was more circular only in the DCMP group with FTR ≥2+ compared with other patients (P < .05 for eccentricity). In multivariate analysis, both RA area (P < .001) and RV volume (P = .002) were independently related to TA dilatation. Conclusions: Based on multiphase CT image analyses, TA dilatation was directly related to RV and RA enlargement. Patients with severe mitral myxomatous disease and nondysfunctional tricuspid valve had yet dilated TA, which questioned the current cut-off recommendation for concomitant tricuspid annuloplasty in this specific population.

Regional assessment of vascular morphology and hemodynamics: methodology and evaluation for abdominal aortic aneurysms after endovascular repair.

Abdominal aortic aneurysm is a deadly disease that can be treated with different endovascular devices that will distinctly alter the aortic morphology. Computational methods can be used to understand the effect of anatomical changes on aortic hemodynamics. We propose a standardized method to assess morphological and hemodynamic changes of the abdominal aorta through the longitudinal axis of the vessel. Patient-specific CFD simulations were used to quantify these changes for two different endografts before and after surgery. Differences in cross-sectional area, blood pressure, peak blood velocity, wall shear stress, and retrograde blood flow were accurately evidenced with the proposed methodology.

Association of calcium density in the thoracic aorta with risk factors and clinical events.

OBJECTIVES: In the ascending aorta, calcification density was independently and inversely associated with cardiovascular disease (CVD) risk prediction. Until now, the density of thoracic aorta calcium (TAC) was estimated as the Agatston score divided by the calcium area (DAG). We thought to analyze TAC density in a full Hounsfield unit (HU) range and to study its association with TAC volume, traditional risk factors, and CVD events. METHODS: Non-enhanced CT images of 1426 patients at intermediate risk were retrospectively reviewed. A calcium density score was estimated as the average of the maximum HU attenuation in all calcified plaques of the entire thoracic aorta (DAV). RESULTS: During a mean 4.0 years follow-up, there were 26 events for a total of 674 patients with TAC > 0. TAC volume and DAV were positively correlated (R = 0.72). The median DAV value was 457 HU (IQ 323-603 HU) and was exponentially related to DAG (R = 0.86). DAV was inversely associated with systolic pressure (p < 0.05), pulse pressure (p < 0.01), hypertension (p < 0.05), and 10-year FRS (p < 0.001) after adjusting for TAC volume. When TAC volume and DAV were included in a logistic model, a significant improvement was shown in CVD risk estimation beyond coronary artery calcium (CAC) (AUC = 0.768 vs 0.814, p < 0.05). In multivariable Cox models, TAC volume and DAV showed an independent association with CVD. CONCLUSIONS: In intermediate risk patients, TAC density was inversely associated with several risk factors after adjustment for TAC volume. A significant improvement was observed over CAC when TAC volume and density were added into the risk prediction model. KEY POINTS: • Calcifications in the aorta can be non-invasively assessed using CT images • A higher calcium score is associated with a higher cardiovascular risk • Measuring the calcifications size and the density separately can improve the risk prediction.

Urinary Bladder Matrix Scaffolds Promote Pericardium Repair in a Porcine Model.

Pericardium closure after cardiac surgery is recommended to prevent postoperative adhesions to the sternum. Synthetic materials have been used as substitutes, with limited results because of impaired remodeling and fibrotic tissue formation. Urinary bladder matrix (UBM) scaffolds promote constructive remodeling that more closely resemble the native tissue. The aim of the study is to evaluate the host response to UBM scaffolds in a porcine model of partial pericardial resection. Twelve Landrace pigs were subjected to a median sternotomy. A 5 × 7 cm pericardial defect was created and then closed with a 5 × 7 cm multilayer UBM patch (UBM group) or left as an open defect (control group). Animals were survived for 8 wk. End points included gross morphology, biomechanical testing, histology with semiquantitative score, and cardiac function. The UBM group showed mild adhesions, whereas the control group showed fibrosis at the repair site, with robust adhesions and injury to the coronary bed. Load at failure (gr) and stiffness (gr/mm) were lower in the UBM group compared with the native pericardium (199.9 ± 59.2 versus 405.3 ± 99.89 g, P = 0.0536 and 44.23 ± 15.01 versus 146.5 ± 24.38 g/mm, P = 0.0025, respectively). In the UBM group, the histology resembled native pericardial tissue, with neovascularization, neofibroblasts, and little inflammatory signs. In contrast, control group showed fibrotic tissue with mononuclear infiltrates and a lack of organized collagen fibers validated with a histologic score. Both groups had normal ultrasonography results without cardiac motility disorders. In this setting, UBM scaffolds showed appropriate features for pericardial repair, restoring tissue properties that could help reduce postsurgical adhesions and prevent its associated complications.

Biomechanical Features of Reinforced Esophageal Hiatus Repair in a Porcine Model.

Recurrence rates in the laparoscopic repair of the hiatal hernia range from 12% to 59%. Limitation of reinforcement has been principally the risk of adverse events caused by synthetic materials. Biologic and resorbable synthetic materials are valid alternatives. This study compares the host response to all these materials after hiatal hernia repair. A total of 20 Landrace pigs, underwent laparoscopic primary hiatal hernia repair and reinforced with a polypropylene mesh (PROLENE: polypropylene [PP]), an absorbable synthetic scaffold (GOREBIO-A: polyglycolic acid [PGA]), a urinary bladder matrix scaffold, (Gentrix: urinary bladder matrix [UBM]), or without reinforcement, control group (C). Animals were survived for 3 months. Endpoints included gross morphology, biomechanical testing, and histology. Pigs in PP and PGA groups showed fibrosis at the repair site, with robust adhesions. In UBM and C groups, only mild adhesions were found. Load at failure (gr) and stiffness (gr/mm) of PP were higher than C group (PP:2103 ± 548.3 versus C:951.1 ± 372.7, P = 0.02; PP:643.3 ± 301 versus C:152.6 ± 142.7, P = 0.01). PGA and UBM values for both parameters were in between PP and C samples. However, stiffness in UBM was tended to be lower than PP group, and approached a significant difference (643.3 ± 301 versus 243 ± 122.1, P = 0.0536). In UBM group, the histology resembled native tissue. By contrast, PP and PGA groups showed mononuclear infiltrates, fibroencapsulation, necrosis, remnants of mesh, and disorganized tissue that was validated with a histologic score. In this setting, UBM scaffolds showed the most appropriate features for hiatal hernia repair, recovering the tissue properties that can help reduce the possibility of early failure and prevent complications associated with the implanted material.

Automatic correction of background phase offset in 4D-flow of great vessels and of the heart in MRI using a third-order surface model.

OBJECTIVE: To evaluate an automatic correction method for velocity offset errors in cardiac 4D-flow acquisitions. MATERIALS AND METHODS: Velocity offset correction was done in a plane-by-plane scheme and compared to a volumetric approach. Stationary regions were automatically detected. In vitro experiments were conducted in a phantom using two orientations and two encoding velocities (Venc). First- to third-order models were fit to the time-averaged images of the three velocity components. In vivo experiments included realistic ROIs in a volunteer superimposed to a phantom. In 15 volunteers, blood flow volume of the proximal and distal descending aorta, of the pulmonary artery (Qp) and the ascending aorta (Qs) was compared. RESULTS: Offset errors were reduced after correction with a third-order model, yielding residual phantom velocities below 0.6 cm/s and 0.4% of Venc. The plane-by-plane correction method was more effective than the volumetric approach. Mean velocities through superimposed ROIs of a volunteer vs phantom were highly correlated (r2 = 0.96). The significant difference between proximal and distal descending aortic flows was decreased after correction from 8.1 to - 1.4 ml (p < 0.001) and Qp/Qs reduced from 1.08 ± 0.09 to 1.01 ± 0.05. DISCUSSION: An automatic third-order model corrected velocity offset errors in 4D-flow acquisitions, achieving acceptable levels for clinical applications.

Abdominal Aortic Aneurysm Volumetric Evaluation During Mid-term Follow-Up After Endovascular Sealing Using the Nellix™ Device.

OBJECTIVES: To analyze the volumetric evolution of abdominal aortic aneurysms after endovascular sealing (EVAS) with the Nellix™ device during follow-up. METHODS: Patients who underwent elective EVAS in our institution in 2014 and 2015 were retrospectively reviewed. Preoperative, postoperative and 1-year scans were processed. A custom software was conceived to assess semi-automated measurements of the aneurysm sac and the endograft sizes including volume, maximum diameter, sectional area and perimeter. Thrombus volume, aneurysm length, mean distance between the stents inside the polymer-filled sacs and endograft migration were also estimated. Manual maximum diameters were measured for comparison. Inter and intra-observer variability of the proposed semi-automated method was evaluated. RESULTS: Pre-EVAS, post-EVAS and last follow-up scans of 12 patients were finally analyzed during a mean follow-up of 17 ± 5 months. No endograft migration or endoleak were detected. During follow-up, aneurysm volume and perimeter slightly increased compared to post-EVAS scans (+ 1 and + 5%, respectively, p < 0.05). A systematic 6% enlargement of the endobag volume was also observed (range 1-15 mL, p < 0.001). Endobag maximum diameter, area and perimeter increased 4, 8, and 8%, respectively (all p < 0.01). Mean plane-by-plane distance between stents increased 4% (p < 0.05). Mean thrombus volume did not change during follow-up, although a high variability was observed. Aneurysm and thrombus volume changes were highly correlated (r = 0.93, p < 0.001). No associations were observed between aneurysm and endobag volume changes. Intra- and inter-observer variability was below 1.7 and 2.4% for diameter and volume measurements, respectively. The automated measurements of post-EVAS aneurysm diameter and volume were higher than preoperative (p < 0.05). Maximum diameters measured manually did not differ between scans. CONCLUSION: Small aneurysm volume enlargement detected during a mid-term follow-up was associated with thrombus size change, whereas systematic endograft expansion resulted independent from the aortic growth. Volumetric measurements using a semi-automated method could quantify small changes in aneurysm, endograft and thrombus sizes not detected by manually defined maximal diameters.

3D aortic morphology and stiffness in MRI using semi-automated cylindrical active surface provides optimized description of the vascular effects of aging and hypertension.

BACKGROUND: Clinically, aortic geometry assessment is mainly based on the measurement of maximal diameters at different anatomic locations, which are subsequently used to indicate prophylactic aortic surgery. However, 3D evaluation of aortic morphology could provide volumetric quantification, which integrates both aortic dilatation and elongation and might thus be more sensitive to early geometric changes than diameters. Precise aortic morphology is also required for the calculation of pulse wave velocity (PWVMRI), an established marker of aortic stiffness. Accordingly, we proposed a 3D semi-automated analysis of thoracic aorta MRI data optimizing morphological and subsequent stiffness assessment. METHODS: We studied 74 individuals (40 males, 50 ± 12years): 21 healthy volunteers and 53 patients with hypertension in whom aortic 3D MRI angiography and 2D + t phase-contrast and cine imaging were performed. A semi-automated method was proposed for volumetric aortic segmentation and was evaluated by studying resulting measurements (length, diameters, volumes and PWVMRI) in terms of: 1) reproducibility, 2) correlations with well-established 2D aortic length and diameters, 3) associations with age, carotid-femoral PWV (cf-PWV) and presence of hypertension. RESULTS: The measurements obtained with the proposed method were reproducible (coefficients of variation ≤ 5.1%) and were highly correlated with 2D measurements (arch length: r = 0.80, Bland-Altman mean bias [limits]: 2.7 mm [-25; 30]; PWVMRI: r = 0.95, 0.22 m/s [-1.9; 2.4]). Higher or similar correlations with age were found for the proposed 3D method compared to the 2D approach (arch length: r = 0.47 (2D), r = 0.60 (3D); PWVMRI: r = 0.63 (2D), r = 0.64 (3D)). Moreover, a significant association was found between PWVMRI and cf-PWV (r = 0.49, p < 0.001). All aortic measurements increased with hypertension (p < 0.05) and with age: arch length (+9mm/decade); diameters: ascending (+1.2mm/decade) and descending aorta (+1.0mm/decade); volumes: ascending (+2.6mL/decade) and descending aorta (+4.0mL/decade); PWVMRI (+1.7  m s-1/decade). CONCLUSIONS: A semi-automated method based on cylindrical active surfaces was proposed for the 3D segmentation of the aorta using a single MRI dataset, providing aortic diameters at anatomical landmarks, aortic volumes and the aortic centerline length used for PWV estimation. Such measurements were reproducible and comparable to expert measurements, which required time-consuming centerline delineation. Furthermore, expected relationships with age and hypertension were found indicating the consistency of our measurements.

Effects on Aortoiliac Fluid Dynamics After Endovascular Sealing of Abdominal Aneurysms.

OBJECTIVES:: To evaluate the effects on aortoiliac fluid dynamics after the implantation of an endograft based on endovascular aneurysm sealing (EVAS) versus endovascular aneurysm repair (EVAR) strategy. METHODS:: An adaptive geometrical deformable model was used for aortic lumen segmentation in 8 patients before and after the surgery. Abdominal aneurysms were treated with an endograft based on the EVAS system (Nellix, n = 4) and with a device based on an anatomical fixation technology (n = 4). Pressure, blood velocity, and wall shear stress (WSS) were estimated at different aortic regions using computational fluid dynamics methods. Physiologic inlet/outlet flow values at the abdominal aorta, the celiac trunk, and the mesenteric and the renal arteries were set. Pressure references were set at iliac arteries outlet. RESULTS:: Maximum aneurysm sizes were similar for both groups in the preoperative scans. The lumen area was lower after EVAR ( P < .05) and EVAS ( P < .01) compared to preoperative aortic lumen sizes. Pressure increase was higher in the proximal abdominal aorta after EVAS compared to EVAR (2.3 ± 0.3 mm Hg vs 0.9 ± 0.3 mm Hg, P < .001). Peak blood velocities inside the endografts were 3-fold higher for EVAS compared to EVAR (54 ± 5 cm/s vs 17 ± 4 cm/s, P < .01). Velocities at the iliac arteries also remained higher for EVAS (38 ± 4 cm/s vs 24 ± 4 cm/s, P < .05). Peak WSS at the iliac arteries remained higher for EVAS compared to EVAR group ( P < .05). CONCLUSION:: The significant modification of the aortic bifurcation anatomy after EVAS alters aortoiliac fluid dynamics, showing a pressure impact at the renal arteries level and an acceleration of the blood velocity at the iliac region with a concomitant increase in peak WSS.

Association of thoracic aorta calcium and non cardiac vascular events in cardiac disease-free individuals.

OBJECTIVE: Thoracic aorta calcium (TAC) is measurable on the same computed tomography (CT) scan as coronary artery calcium (CAC) but has still unclear clinical value. We assessed TAC and CAC relations with non-cardiac vascular events history in a cohort of subjects at risk for cardiovascular disease. METHODS: We analyzed retrospectively 1000 consecutive subjects having undergone CAC detection by non-contrast multi-slice CT with measurement field longer than usual in order to measure total TAC including aortic arch calcium. We also determined partial TAC restricted to ascending and descending thoracic aorta sites by removing arch calcium from total TAC. Calcium deposits were measured with a custom made software using Agatston score. RESULTS: Compared with the rest of the cohort, the 30 subjects with non-cardiac vascular event history had higher median values [95% CI] of total TAC (282 [28-1809] vs 39 [0-333], p < 0.01) and partial TAC (4 [0-284] vs 0 [0-5], p < 0.01) but no different value of CAC (73 [0-284] vs 16 [0-148]). Odds ratio [95% CI] of having non-cardiac vascular event per 1-SD increase in log-transformed calcium value was significant for total TAC but not for CAC, if total TAC and CAC were entered separately (1.56 [1.12-2.24], p < 0.01 and 1.13 [0.86-1.50], respectively) or together (1.57 [1.10-2.32], p < 0.01 and 0.98 [0.73-1.32], respectively) in the logistic adjusted model. CONCLUSION: TAC assessment simultaneous with CAC detection provides complementary information on the extra coronary component of cardiovascular risk beyond CAC's coronary risk prediction. Further studies are required to prospectively confirm this result.

Calcifications of the thoracic aorta on extended non-contrast-enhanced cardiac CT.

BACKGROUND: The presence of calcified atherosclerosis in different vascular beds has been associated with a higher risk of mortality. Thoracic aorta calcium (TAC) can be assessed from computed tomography (CT) scans, originally aimed at coronary artery calcium (CAC) assessment. CAC screening improves cardiovascular risk prediction, beyond standard risk assessment, whereas TAC performance remains controversial. However, the curvilinear portion of the thoracic aorta (TA), that includes the aortic arch, is systematically excluded from TAC analysis. We investigated the prevalence and spatial distribution of TAC all along the TA, to see how those segments that remain invisible in standard TA evaluation were affected. METHODS AND RESULTS: A total of 970 patients (77% men) underwent extended non-contrast cardiac CT scans including the aortic arch. An automated algorithm was designed to extract the vessel centerline and to estimate the vessel diameter in perpendicular planes. Then, calcifications were quantified using the Agatston score and associated with the corresponding thoracic aorta segment. The aortic arch and the proximal descending aorta, "invisible" in routine CAC screening, appeared as two vulnerable sites concentrating 60% of almost 11000 calcifications. The aortic arch was the most affected segment per cm length. Using the extended measurement method, TAC prevalence doubled from 31% to 64%, meaning that 52% of patients would escape detection with a standard scan. In a stratified analysis for CAC and/or TAC assessment, 111 subjects (46% women) were exclusively identified with the enlarged scan. CONCLUSIONS: Calcium screening in the TA revealed that the aortic arch and the proximal descending aorta, hidden in standard TA evaluations, concentrated most of the calcifications. Middle-aged women were more prone to have calcifications in those hidden portions and became candidates for reclassification.

Towards automatic measurement of anteversion and neck-shaft angles in human femurs using CT images.

Automatic assessment of human femur morphology may provide useful clinical information with regard to hip and knee surgery, prosthesis design and management of hip instability. To this end, neck-shaft and anteversion angles are usually used. We propose a full automatic method to estimate these angles in human femurs. Multislice CT images from 18 dried bones were analysed. The algorithm fits 3D cylinders to different regions of the bone to estimate the angles. A manual segmentation and a conventional angle assessment were used for validation. We found anteversion angle as 20 ± 7° and neck-shaft angle as 130 ± 9°. Mean distances from femur surface to cylinders were 5.5 ± 0.6, 3.5 ± 0.6 and 2.4 ± 0.4 mm for condyles, diaphysis and neck regions, respectively. Automatic and conventional angles were positively correlated (r(2)>0.85). Manual and automatic segmentations did not differ. The method was fast and 100% reproducible. A robust in vivo segmentation algorithm should be integrated to advance towards a clinically compliant methodology.

Angle estimation of human femora in a three-dimensional virtual environment.

The estimation of human femur morphology and angulation provide useful information for assisted surgery, follow-up evaluation and prosthesis design, cerebral palsy management, congenital dislocation of the hip and fractures of the femur. Conventional methods that estimate femoral neck anteversion employ planar projections because accurate 3D estimations require complex reconstruction routines. In a recent work, we proposed a cylinder fitting method to estimate bifurcation angles in coronary arteries and we thought to test it in the estimation of femoral neck anteversion, valgus and shaft-neck angles. Femora from 10 patients were scanned using multisliced computed tomography. Virtual cylinders were fitted to 3 regions of the bone painted by the user to automatically estimate the femoral angles. Comparisons were made with a conventional manual method. Inter- and intra-reading measurements were evaluated for each method. We found femoral angles from both methods strongly correlated. Average anteversion, neck-shaft and valgus angles were 17.5°, 139.5°, 99.1°, respectively. The repeatability and reproducibility of the automated method showed a 5-fold reduction in inter- and intra-reading variability. Accordingly, the coefficients of variation for the manual method were below 25% whereas for the automated method were below 6%. The valgus angle assessment was globally the most accurate with differences below 1°. Maximum distances from true surface bone points and fitting cylinders attained 6 mm. The employment of virtual cylinders fitted to different regions of human femora consistently helped to assess true 3D angulations.