Lumen Volume Research Articles

Endovascular management of chronic symptomatic aortic dissection with the Streamliner Multilayer Flow Modulator: Twelve-month outcomes from the global registry

ObjectiveReported are initial 12-month outcomes of patients with chronic symptomatic aortic dissection managed by the Streamliner Multilayer Flow Modulator (SMFM; Cardiatis, Isnes, Belgium). Primary end points were freedom from rupture- and aortic-related death, and reduction in false lumen index. Secondary end points were patency of great vessels and visceral branches, and freedom of stroke, paraplegia, and renal failure. MethodsOut of 876 SMFM implanted globally, we have knowledge of 542. To date, 312 patients are maintained in the global registry, of which 38 patients were identified as having an aortic dissection (12.2%). Indications included 35 Stanford type B dissections, two Stanford type A and B dissections, and one mycotic Stanford type B dissection. ResultsThere were no reported ruptures or aortic-related deaths. All cause survival was 85.3% Twelve-month freedom from neurologic events was 100%, and there were no incidences of end-organ ischemia, paraplegia or renal insult. Morphologic analysis exhibited dissection remodeling by a reduction in longitudinal length of the dissected aorta, and false lumen volume. A statistically significant reduction in false lumen index (P = .016) at 12 months, and a borderline significant increase in true lumen volume (P = .053) confirmed dissection remodeling. ConclusionsThe SMFM is an option in management of complex pan-aortic dissection. Results highlight SMFM implantation leads to dissection stabilization with no further aneurysm progression, and no retrograde type A dissection. Thoracic endovascular aneurysm repair by SMFM ensued in freedom from aortic rupture, neurologic stroke, paraplegia and renal failure. Further analysis of the global registry data will inform long-term outcomes.

Gender, smoking, body size, and aneurysm geometry influence the biomechanical rupture risk of abdominal aortic aneurysms as estimated by finite element analysis

ObjectiveFinite element analysis (FEA) has been suggested to be superior to maximal diameter measurements in predicting rupture of abdominal aortic aneurysms (AAAs). Our objective was to investigate to what extent previously described rupture risk factors were associated with FEA-estimated rupture risk. MethodsOne hundred forty-six patients with an asymptomatic AAA of a 40- to 60-mm diameter were retrospectively identified and consecutively included. The patients' computed tomography angiograms were analyzed by FEA without (neutral) and with (specific) input of patient-specific mean arterial pressure (MAP), gender, family history, and age. The maximal wall stress/wall strength ratio was described as a rupture risk equivalent diameter (RRED), which translated this ratio into an average aneurysm diameter of corresponding rupture risk. ResultsIn multivariate linear regression, RREDneutral increased with female gender (3.7 mm; 95% confidence interval [CI], 0.13-7.3) and correlated with patient height (0.27 mm/cm; 95% CI, 0.11-0.43) and body surface area (BSA, 16 mm/m2; 95% CI, 8.3-24) and inversely with body mass index (BMI, −0.40 mm/kg m−2; 95% CI, −0.75 to −0.054) in a wall stress-dependent manner. Wall stress-adjusted RREDneutral was raised if the patient was currently smoking (1.1 mm; 95% CI, 0.21-1.9). Age, MAP, family history, and patient weight were unrelated to RREDneutral. In specific FEA, RREDspecific increased with female gender, MAP, family history positive for AAA, height, and BSA, whereas it was inversely related to BMI. All results were independent of aneurysm diameter. Peak wall stress and RRED correlated with aneurysm diameter and lumen volume. ConclusionsFemale gender, current smoking, increased patient height and BSA, and low BMI were found to increase the mechanical rupture risk of AAAs. Previously described rupture risk factors may in part be explained by patient characteristic-dependent variations in aneurysm biomechanics.

The effects of statin therapy on carotid plaque composition and volume: A systematic review and meta-analysis

Background and purposePrior studies have demonstrated that statin use stabilizes and diminishes atherosclerotic lesions. The main objective of this systematic review and meta-analysis was to study the effects of statin therapy on carotid plaque composition as seen on serial high-resolution carotid plaque MRI. We hypothesized that statin therapy would result in significant improvements in lipid-rich-necrotic-core (LRNC) volumes, wall volumes and lumen volumes. Materials and methodsProspective studies using serial high-resolution carotid plaque MRI (1.5 or 3T only) in patients on statin therapy to document changes in carotid plaque composition were included. All studies had a minimum of 10 patients and minimum follow-up duration of 3 months. Outcomes included change in LRNC volume, wall volume, and lumen volume at: (1) 1–6 months; (2) 7–12 months; (3) >12 months following initiation of statin therapy; and (4) at last follow-up. Meta-analysis was performed using the random effects model. Results were reported as weighted mean differences (WMD) and 95% confidence interval (CI). ResultSeven studies including 361 patients were included. There was no significant change in carotid wall volume or lumen volume at any time points. While there was no significant difference in LRNC at 1–6 months and at 7–12 months following initiation of statin therapy; at >12 months, there was significant decrease in LRNC volume (WMD=−9.9mm3, 95% CI=−8.9, −2.3). ConclusionsOur study suggests statin therapy is associated with significant reductions in LRNC at 1-year of statin therapy on serial carotid MRI. However, no significant reduction in carotid wall volume was seen.

Protective properties of the arterial system against peripherally generated waves

An anatomically detailed model consisting of a network of electric transmission lines is developed to simulate propagation of the pulse waves in humans. The simulations show that the real arterial tree geometry, together with the elastic and rheological parameters of particular segments, ensure an efficient protection of vital organs against pulse waves generated at peripheral locations. Because locomotive movements are the most obvious source of such disturbances, additional cyclic perturbations are applied to the model femoral arteries. It is shown that the impact of such peripherally generated pulse waves onto the pressure profiles at the ascending aorta and at other vital locations of the system is surprisingly weak independently of synchronization/desynchronization with the heart action period. This may witness to an intrinsically protective nature of the arterial tree anatomy in addition to its known functionality of the optimal blood supply at possibly low lumen volume. The extent of the protection is also studied in the presence of a complete arterial embolism at the left common carotid artery.

Mature proprotein convertase subtilisin/kexin type 9, coronary atheroma burden, and vessel remodeling in heterozygous familial hypercholesterolemia

Proprotein convertase subtilisin/kexin type 9 (PCSK9), an important contributor to low-density lipoprotein metabolism in heterozygous familial hypercholesterolemia (HeFH), exhibits direct proatherogenic effects. PCSK9 circulates as mature and furin-cleaved forms, which differ in its biological activity. However, it remains to be elucidated whether each PCSK9 subtype has different atherogenic properties. To investigate the association of each PCSK9 subtype with coronary atherosclerosis in HeFH. About 204 nonculprit segments in 138 HeFH subjects with coronary artery disease were evaluated by using intravascular ultrasound. Mature, furin-cleaved PCSK9 and total concentration of PCSK9 subtypes were measured by using enzyme-linked immunosorbent assay (BML Inc., Tokyo, Japan). The relationship of these PCSK9 values with intravascular ultrasound measures was investigated. Mature PCSK9 level was positively associated with percent atheroma volume (PAV: r=0.78, P=.003). Despite extensive atheroma under a higher mature PCSK9 level, vessel volume did not change across any mature PCSK9 levels (r=0.05, P=.78). These responses resulted in smaller lumen volume, which was negatively correlated to mature PCSK9 level (r=0.65, P=.009). By contrast, there were no significant relationships of PAV with furin-cleaved (r=0.12, P=.45) and total PCSK9 (r=0.37, P=.25) levels. On multivariate analysis, mature PCSK9 level independently contributed to PAV (odds ratio: 1.45, 95% confidence interval: 1.11-1.67, P=.01). Even in subjects with low-density lipoprotein cholesterol level <2.6mmol/L, greater PAV was still observed in association with an elevated mature PCSK9 level (P=.003). Mature PCSK9 associated with atheroma volume and impaired vessel remodeling in HeFH patients with coronary artery disease. These findings suggest the potential role of mature PCSK9 in propagation of coronary atherosclerosis in HeFH.

Relationship between Automated Coronary Calcium Volumes and a Set of Manual Coronary Lumen Volume, Vessel Volume and Atheroma Volume in Japanese Diabetic Cohort.

A high degree of correlation exists between Coronary Artery Diseases (CAD) and calcification of the vessel wall. For Percutaneous Coronary Interventional (PCI) planning, it is essential to have an exact understanding of the extent to which calcium volume is correlated to the lumen, vessel, and atheroma volume regions in the coronary artery, which is unclear in recent studies. Four automated Coronary Calcium Volume (aCCV) measurement methods {threshold, Fuzzy c-Means (FCM), K-means, and Hidden Markov Random Field (HMRF)} and its correlation with three manual (experts) coronary parameters namely: Coronary Vessel Volume (mCVV), Coronary Lumen Volume (mCLV), and Coronary Atheroma Volume (mCAV), was determined in a Japanese diabetic cohort. Intravascular Ultrasound (IVUS) image dataset from 19 patients (around 40,090 frames) was collected using 40 MHz IVUS catheter (Atlantis® SR Pro, Boston Scientific®, pullback speed of 0.5 mm/sec). The methodology consisted of automatically computing the calcium volume in the entire IVUS coronary videos using FCM, K-means, and HMRF based pixel classification and comparing it against the previously published threshold-based method. The Coefficient of Correlation (CC) was then established between the four aCCV and three manually (experts) coronary parameters: mCVV, mCLV, and mCAV computed using iMAP software Boston Scientific®. Statistical tests (Two-tailed paired Student t-test, Wilcoxon signed rank test, Mann-Whitney test, Chi-square test, and Kolmogorov-Smirnov KS-test) were performed to demonstrate consistency, reliability, and accuracy of the proposed work. Correlation coefficient of: (a) automated threshold-based volume; (b) automated FCM based volume; (c) automated K-means based volume; and (d) automated HMRF based volume and corresponding three manually (expert's) coronary parameters (mCLV, mCVV, mCAV) were: (0.51, 0.40, 0.48), (0.52, 0.38, 0.49), (0.56, 0.45, 0.52), and (0.57, 0.42, 0.56), respectively. The CC between age and haemoglobin was 0.50. Automated coronary volume measurement using HMRF method is more accurate compared to threshold, FCM, and K-means-based method, since it is more strongly correlated with three expert's readings.

Lipid-core burden response to stent implantation assessed with near-infrared spectroscopy and intravascular ultrasound evaluation in patients with myocardial infarction.

Near-infrared spectroscopy (NIRS) is a new method to identify lipid core plaque (LCP). The LCP and vascular response were assessed with NIRS to examine whether LCP was compressed or redistributed during percutaneous coronary intervention with stent implantation. In 25 patients with non-ST segment elevation myocardial infarction (NSTEMI) NIRS acquisition was performed after predilation, stent implantation with nominal pressure and high-pressure post-dilation with a non-compliant balloon. The intravascular ultrasound (IVUS) measures included volumes of external elastic membrane (EEM), lumen and plaque+media. The NIRS measures included lipid core burden index (LCBI) and maximum value of LCBI for any of the 4-mm segment (maxLCBI4mm). From predilation to stent implantation and post-dilation EEM volume increased from 337±124mm3 to 369±136mm3 and to 397±144mm3 (p<0.001), while plaque volume decreased from 225±84mm3 to 202±85mm3 and to 192±81mm3 (p<0.001). Plaque shift to the proximal reference segment was found in 40% of the lesions. The maxLCBI4mm decreased significantly from predilation to stent implantation (492±235 to 208±193 (p<0.001), whereas post dilation did not cause any further significant reduction. Also LCBI decreased significantly from predilation to stent implantation (173±103 to 68±67, p<0.001), without any further significant reduction during post-dilation. The LCBI did neither in the proximal nor in the distal reference segments change significantly during stent implantation or post-dilation. Lumen enlargement was caused by vessel expansion, plaque compression and longitudinally plaque redistribution. Lipid-core burden at the stented segment was decreased.

Comparative assessment of \u201cplaque/media\u201d change on three modalities of IVUS immediately after implantation of either everolimus-eluting bioresorbable vascular scaffold or everolimus-eluting metallic stent in Absorb II study

The purpose of the study to assess the comparability of immediate changes in plaque/media volume (PV) on three modalities of intravascular ultrasound (IVUS) after implantation of either bioresorbable vascular scaffold (BVS) or everolimus-eluting metallic stent (EES) in Absorb II Study. The two devices have different device volume and ultrasound backscattering that may interfere with the “plaque/media” assessed by three modalities on IVUS: grayscale, backscattering of radiofrequency and brightness function. In a multicenter randomized controlled trial, 501 patients with stable or unstable angina underwent documentary IVUS pre- and post- implantation. The change in plaque/media volume (PV) was categorized into three groups according to the relative PV change in device segment: PV “increased” >+5% (PVI), PV unchanged ±5% (PVU), and PV decreased <−5% (PVD). The change in PV was re-evaluated three times: after subtraction of theoretical device volume, after analysis of echogenicity based on brightness function. In 449 patients, 483 lesions were analyzed pre- and post-implantation. “PVI” was more frequently observed in BVS (53.8%) than EES group (39.4%), p = 0.006. After subtraction of the theoretical device volume, the frequency of “PVI” decreased in both BVS (36.2%) and EES (32.1%) groups and became comparable (p = 0.581). In addition, the percentage of “PVI” was further reduced in both device groups after correction for either radiofrequency backscattering (BVS 34.4% vs. EES 22.6%) or echogenicity (BVS 25.2% vs. EES 9.7%). PV change in device segment was differently affected by BVS and EES devices implantation due to their differences in device volume and ultrasound backscattering. It implies that the lumen volume was also artifactually affected by the type of device implanted. Comparative IVUS assessment of lumen and plaque/media volume changes following implantation of BVS and EES requires specific methodological adjustment.

Computational fluid analysis of symptomatic chronic type B aortic dissections managed with the Streamliner Multilayer Flow Modulator

ObjectiveManaging symptomatic chronic type B aortic dissection (SCTBAD) by the Streamliner Multilayer Flow Modulator (SMFM) stent (Cardiatis, Isnes, Belgium) is akin to provisional structural support to induce complete attachment of the dissection flap, but with the ability of aortic remolding. This study investigated the SMFM's capability to enact healing of SCTBAD. MethodsClinical data for 12 cases comprising preoperative and postoperative treatment of SCTBAD were obtained from a multicenter database hosted by the Multilayer Flow Modulator Global Registry, Ireland. A biomechanical analysis, by means of computational fluid dynamics modeling, of the hemodynamic effects and branch patency associated with the use of the SMFM was performed for all cases. The mean length of the dissections was 30.23 ± 13.3 cm. There were 30 SMFMs used, which covered 69 aortic branches. ResultsAt 1-year follow-up, the true lumen volume increased from 175.74 ± 98.83 cm3 to 209.87 ± 128.79 cm3; the false lumen decreased from 135.2 ± 92.03 cm3 to 123.19 ± 110.11 cm3. The false lumen index decreased from 0.29 ± 0.13 (preoperatively) to 0.21 ± 0.15 (postoperatively). The primary SMFM treatment of SCTBAD increased carotid perfusion by 35% ± 21% (P = .0216) and suprarenal perfusion by 78% ± 32% (P = .001). The wall pressure distribution blended along the newly enlarged true lumen, whereas the false lumen wall pressure decreased by 6.23% ± 4.81% for the primary group (cases 1-7) and by 3.84% ± 2.59% for the secondary group (cases 8-12). ConclusionsSMFM reduces the false lumen wall pressure through flow modulation. It preserves patency of all branches, minimizing the incidence of short-term complications. The SMFM is a valuable option in managing primary SCTBAD, without midterm complications.

Anatomical characteristics and physical–mechanical properties of Neosinocalamus affinis from Southwest China

The anatomical characteristics and physical–mechanical properties of Neosinocalamus affinis culms from three locations in China were investigated. The fiber percentage, length, wall thickness, basic density, and mechanical properties all increased with culm height, while the fiber lumen diameter and volume shrinkage showed an inverse trend. The site had significant influence on the fiber percentage and physical–mechanical properties, while the influence on vascular bundle density and fiber morphology was not significant. Therefore, the influences of site on bamboo properties may be taken into consideration for constructional utilization, and those for pulping may be ignored.

Age-related changes of thoracic aorta geometry used to predict the risk for acute type B dissection

AimsRisk models that use a single aortic diameter threshold have failed to successfully predict acute type B aortic dissection (TBAD). We sought to identify meaningful age-indexed anatomical variables to predict TBAD risk. Methods and resultsA geometric deformable model, consisting of virtual elastic balloons that inflate inside a vessel lumen, was developed to quantify thoracic aorta geometry. In the presence of TBAD, true and total artery lumen morphology were assessed. A stepwise logistic model was built to predict TBAD risk. Initial covariates included age, gender, body mass index and all anatomic variables not directly related to the dissected segment. Patients with acute TBAD (n=34, 62±12years old, 57% male gender) were compared with subjects with symptoms of dissection, but with a subsequent negative diagnosis (n=51, 62±12years old, 76% male gender). Patient risk factors did not differ between groups. Most aortic anatomical variables were age-dependent. Aortic size was larger in every segment of the dissected with respect to non-dissected aortas (p<0.001). Variables entering the TBAD risk prediction model were aortic arch diameter, thoracic aorta length and age (predictability=0.9764, r=0.85), confirmed by a bootstrap internal validation. In dissected aortas, the true lumen volume was correlated to age (r=0.72). ConclusionsTBAD probability increases with a larger aortic arch diameter and a longer thoracic aorta, whereas threshold values increase with age. The aortic morphology was age-dependent. After dissection, true lumen volume correlated to age. The use of threshold values indexed to age should be encouraged to better prevent and eventually treat TBAD.

Prognostic implications of descending thoracic aorta dilation after surgery for aortic dissection

BackgroundThe present study assessed whether descending thoracic aorta growth can be measured reliably by volumetric analysis using multi-detector row computed tomography (MDCT) and whether growth influences the need for future aortic interventions in survivors of acute type A aortic dissection. MethodsA total of 51 patients (58 ± 11 years, 61% male) who underwent surgery for type A aortic dissection with ≥2 postoperative MDCT scans ≥5 months apart were included. Volumetric analysis of the descending thoracic aorta was performed with acceptable intraobserver variability. Growth of the complete, false and true lumen was estimated in ml/year and defined as slow growth (≤average growth) or fast growth (>average growth). ResultsThe complete lumen volume increased from 133 ± 8 ml to 163 ± 9 ml after 3.5 years follow-up (p < 0.001), with an average growth rate of 6.1 ml/year. The false lumen volume increased from 81 ± 7 ml to 106 ± 12 ml (p = 0.018) with an average growth rate of 2.8 ml/year. The true lumen changed only slightly from 59 ± 4 ml to 65 ± 8 ml (p = 0.205). Five-year freedom from descending thoracic aorta intervention was significantly lower in patients with above-average growth of the complete lumen (80 ± 9%) compared to slow growth (100%; p = 0.003). Similar observations were made for the false lumen (fast: 74 ± 12% vs. slow: 100%; p = 0.042). ConclusionsIncreased growth of the false lumen of the descending thoracic aorta after type A aortic dissection was associated with a higher risk of secondary interventions.

Determinants of carotid atherosclerotic plaque burden in a stroke-free population

Background and aimsIn a large stroke-free population, we sought to identify cardiovascular risk factors and carotid plaque components associated with carotid plaque burden, lumen volume and stenosis. MethodsThe carotid arteries of 1562 stroke-free participants from The Rotterdam Study were imaged on a 1.5-Tesla MRI scanner. Inner and outer wall of the carotid arteries were automatically segmented and lumen volume (mm3), wall volume (outer wall–inner wall) and plaque burden (wall volume/outer wall volume) (%) were quantified. Plaque components were visually determined and luminal stenosis was assessed. We analyzed associations of cardiovascular risk factors and carotid plaque components with plaque burden and lumen volumes using regression analysis. ResultsWe investigated 2821 carotid plaques and found that women had larger plaque burden (50.7 ± 7.8% vs. 49.2 ± 7.7%, p < 0.0001) and smaller lumen volumes (933 ± 286 mm3vs. 1078 ± 334 mm3, p < 0.0001) than men. In women, age, HDL-cholesterol and systolic blood pressure, and in men, total cholesterol, non-HDL cholesterol and statin use were independently associated with higher plaque burden and lumen volume. Furthermore, smoking and diabetes were associated with lumen volume in men (respectively p = 0.04 and p = 0.002). Intraplaque hemorrhage (IPH) and lipid were related to a larger plaque burden (OR 1.30 [1.05–1.60] and OR 1.28[1.06–1.55]). Finally, within the highest quartile of plaque burden, IPH was strongly associated with luminal stenosis independent of age, sex, plaque burden and composition (Beta = 15.2; [11.8–18.6]). ConclusionsSeveral cardiovascular risk factors and plaque components, in particular IPH, are associated with higher plaque burden. Carotid IPH is strongly associated with an increased luminal stenosis.

FFR Derived From Coronary CT Angiography in Nonculprit Lesions of Patients With Recent STEMI

ObjectivesThis study sought to determine the diagnostic performance of noninvasive fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (FFRCT) for the diagnosis of lesion-specific ischemia in nonculprit vessels of patients with recent in ST-segment elevation myocardial infarction (STEMI). BackgroundIn patients with stable angina, FFRCT has high diagnostic performance in identification of ischemia-causing lesions. The potential value of FFRCT for assessment of multivessel disease in patients with recent STEMI has not been evaluated. MethodsCoronary CTA with calculation of FFRCT and invasive coronary angiography with FFR were performed 1 month after STEMI in patients with multivessel disease. Coronary CTA and invasive coronary angiography stenosis >50% were considered obstructive. Lesion-specific ischemia was assumed if FFRCT was ≤0.80. FFR ≤0.80 was the reference standard. To evaluate the influence of vessel size, the total coronary vessel lumen volume relative to left ventricular mass (volume-to-mass ratio) was calculated and compared with that of patients with stable angina. ResultsThe study evaluated 124 nonculprit vessels from 60 patients. Accuracy, sensitivity, and specificity of FFRCT were 72%, 83%, and 66% versus 64% (p = 0.033), 93% (p = 0.15), and 49% (p < 0.001) for CTA and 72% (p = 1.00), 76% (p = 0.46), and 70% (p = 0.54) for invasive coronary angiography. Following STEMI, median volume-to-mass ratio was lower than in patients with stable angina, 53 versus 65 mm3/g (p = 0.009). In patients with volume-to-mass ratio ≥65 mm3/g (upper tertile) accuracy, sensitivity, and specificity of FFRCT were all 83% versus 56% (p = 0.009), 75% (p = 0.61), and 44% (p = 0.003) in patients with <49 mm3/g (lower tertile). ConclusionsThe diagnostic performance of FFRCT for staged detection of ischemia in STEMI patients with multivessel disease is moderate. STEMI patients have a smaller vessel volume than do patients with stable angina. The diagnostic performance of FFRCT is influenced by the volume-to-mass ratio. This study does not support routine use of FFRCT in the post-STEMI setting. (Assessment of Coronary Stenoses Using Coronary CT-Angiography and Noninvasive Fractional Flow Reserve; NCT01739075)

P12 Pathological vascular smooth muscle cells remodelling in murine models of abdominal aortic aneurysm

Rationale Abdominal aortic aneurysm (AAA) is a focal dilation of the abdominal aorta that progresses to rupture, which is frequently fatal. The only existing treatments are high risk surgical interventions. These are not offered until the AAA is large (>5.5?cm) so patients remain under surveillance for many years. There is currently no medical therapy to offer. We have previously observed a senescent phenotype in vascular smooth muscle cells (VSMC) isolated from end-stage human AAA. We hypothesise that there is a prior period of pathological VSMC remodelling which may be a promising and novel target for molecular therapies. Methodology Three murine models of early AAA were used – (i) AngII infusion to ApoE-/- mice and (ii) CaCl2 or (iii) porcine pancreatic elastase application to the aortic adventitia of C57BL6/J mice. VSMC remodelling was investigated in fixed and paraffin embedded aortic tissue harvested from the murine models using the histochemical stain Movat’s Pentachrome and immunohistochemistry for the VSMC identification marker, αSMA. Slides were imaged with a digital slide scanner or confocal microscopy as appropriate. Aortic lumen volume was determined by in-vivo ultrasound. Results We observed VSMC remodelling in all three models of AAA. The remodelling was reduced by administration of a novel small-molecule inhibitor of PDGF induced VSMC remodelling. Inhibition of VSMC remodelling also reduced the severity of the aneurysms formed as assessed by 3D in-vivo ultrasound of the aortic lumen. Conclusions There is a major VSMC remodelling response in murine AAA and disrupting this response appears to suppress AAA formation.

Quantification by optical coherence tomography imaging of the ablation volume obtained with the Orbital Atherectomy System in calcified coronary lesions.

Recently, favourable procedural 30-day and one-year outcomes with the Diamondback 360 Orbital Atherectomy System (OAS) in the treatment of severely calcified lesions have been reported. The purpose of this study was to assess the therapeutic mechanism and efficacy of the OAS with optical coherence tomography (OCT) imaging. This was an observational imaging study in 18 patients with complex calcified coro-nary artery lesions who underwent percutaneous coronary intervention with the OAS. Pre-OAS and post-OAS OCT analyses demonstrated that the minimum lumen area (MLA) increased from 2.07±0.66 mm2 to 2.38±0.68 mm2 with a lumen volume increase of 9.68±17.22 mm3 in the ablated segment with a length of 30.7±13.1 mm. The maximal vessel injury (dissection) involved the intima in 39% and the media in 6% of the study population. To eliminate the influence of post-OAS vasoconstriction, the ablation area was measured with the interpolated original lumen surface by comparing the endoluminal border of the pre-OAS image. The ablation area at the maximal ablated cross-section was 0.55±0.41 mm2, and the ablation volume by OAS was 2.68±2.80 mm3. OAS effectively ablated coronary calcified tissue with some degree of intimal dissection. OCT imaging can be used to assess the total ablation volume after orbital atherectomy.

Freehand three-dimensional ultrasound imaging of carotid artery using motion tracking technology

Ultrasound imaging has been extensively used for determining the severity of carotid atherosclerotic stenosis. In particular, the morphological characterization of carotid plaques can be performed for risk stratification of patients. However, using 2D ultrasound imaging for detecting morphological changes in plaques has several limitations. Due to the scan was performed on a single longitudinal cross-section, the selected 2D image is difficult to represent the entire morphology and volume of plaque and vessel lumen. In addition, the precise positions of 2D ultrasound images highly depend on the radiologists’ experience, it makes the serial long-term exams of anti-atherosclerotic therapies are difficult to relocate the same corresponding planes by using 2D B-mode images. This has led to the recent development of three-dimensional (3D) ultrasound imaging, which offers improved visualization and quantification of complex morphologies of carotid plaques. In the present study, a freehand 3D ultrasound imaging technique based on optical motion tracking technology is proposed. Unlike other optical tracking systems, the marker is a small rigid body that is attached to the ultrasound probe and is tracked by eight high-performance digital cameras. The probe positions in 3D space coordinates are then calibrated at spatial and temporal resolutions of 10μm and 0.01s, respectively. The image segmentation procedure involves Otsu’s and the active contour model algorithms and accurately detects the contours of the carotid arteries. The proposed imaging technique was verified using normal artery and atherosclerotic stenosis phantoms. Human experiments involving freehand scanning of the carotid artery of a volunteer were also performed. The results indicated that compared with manual segmentation, the lowest percentage errors of the proposed segmentation procedure were 7.8% and 9.1% for the external and internal carotid arteries, respectively. Finally, the effect of handshaking was calibrated using the optical tracking system for reconstructing a 3D image.

Influence of Adaptive Statistical Iterative Reconstruction on coronary plaque analysis in coronary computed tomography angiography

PurposeThe purpose of this study was to study the effect of iterative reconstruction (IR) software on quantitative plaque measurements in coronary computed tomography angiography (CCTA). MethodsThirty patients with a three clinical risk factors for coronary artery disease (CAD) had one CCTA performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each reconstruction. Lumen and plaque intensity measurements and HU based plaque characterization were based on corrected contours copied to each reconstruction. ResultsNo significant changes between FBP and 30% ASIR were found except for lumen- (−2.53 HU) and plaque intensities (−1.28 HU). Between FBP and 60% ASIR the change in total volume showed an increase of 0.94%, 4.36% and 2.01% for lumen, plaque and vessel, respectively. The change in total plaque burden between FBP and 60% ASIR was 0.76%. Lumen and plaque intensities decreased between FBP and 60% ASIR with −9.90 HU and −1.97 HU, respectively. The total plaque component volume changes were all small with a maximum change of −1.13% of necrotic core between FBP and 60% ASIR. ConclusionsQuantitative plaque measurements only showed modest differences between FBP and the 60% ASIR level. Differences were increased lumen-, vessel- and plaque volumes, decreased lumen- and plaque intensities and a small percentage change in the individual plaque component volumes.

First experiences with model based iterative reconstructions influence on quantitative plaque volume and intensity measurements in coronary computed tomography angiography

PurposeInvestigate the influence of adaptive statistical iterative reconstruction (ASIR) and the model-based IR (Veo) reconstruction algorithm in coronary computed tomography angiography (CCTA) images on quantitative measurements in coronary arteries for plaque volumes and intensities. MethodsThree patients had three independent dose reduced CCTA performed and reconstructed with 30% ASIR (CTDIvol at 6.7 mGy), 60% ASIR (CTDIvol 4.3 mGy) and Veo (CTDIvol at 1.9 mGy). Coronary plaque analysis was performed for each measured CCTA volumes, plaque burden and intensities. ResultsPlaque volume and plaque burden show a decreasing tendency from ASIR to Veo as median volume for ASIR is 314 mm3 and 337 mm3–252 mm3 for Veo and plaque burden is 42% and 44% for ASIR to 39% for Veo. The lumen and vessel volume decrease slightly from 30% ASIR to 60% ASIR with 498 mm3–391 mm3 for lumen volume and vessel volume from 939 mm3 to 830 mm3. The intensities did not change overall between the different reconstructions for either lumen or plaque. ConclusionWe found a tendency of decreasing plaque volumes and plaque burden but no change in intensities with the use of low dose Veo CCTA (1.9 mGy) compared to dose reduced ASIR CCTA (6.7 mGy & 4.3 mGy), although more studies are warranted.

Magnetic Resonance Venous Volume Measurements in Peripheral Artery Disease (from ELIMIT)

The relation between the arterial and venous systems in patients with impaired lower extremity blood flow remains poorly described. The objective of this secondary analysis of the Effectiveness of Intensive Lipid Modification Medication in Preventing the Progression on Peripheral Artery Disease Trial was to determine the association between femoral vein (FV) volumes and measurements of peripheral artery disease. FV wall, lumen, and total volumes were quantified with fast spin-echo proton density-weighted magnetic resonance imaging scans in 79 patients with peripheral artery disease over 2 years. Reproducibility was excellent for FV total vessel (intraclass correlation coefficient 0.924, confidence interval 0.910 to 0.935) and lumen volumes (intraclass correlation coefficient 0.893, confidence interval 0.873 to 0.910). Baseline superficial femoral artery volumes were directly associatedwith FV wall (r= 0.46, p <0.0001), lumen (r= 0.42, p=0.0001),and totalvolumes (r=0.46, p <0.0001). The 2-year change in maximum walking time was inversely associated with the 24-month change in FV total volume (r=-0.45, p= 0.03). Inconclusion, FV volumes can be measured reliably with fast spin-echo proton density-weighted magnetic resonance imaging, and baseline superficial femoral artery plaque burden is positively associated with FV volumes, whereas the 2-year change in FV volumes and leg function show an inverse relation.