Assessment of pulmonary vascular anatomy: comparing augmented reality by holograms versus standard CT images/reconstructions using surgical findings as reference standard.

BACKGROUND: We compared computed tomography (CT) images and holograms (HG) to assess the number of arteries of the lung lobes undergoing lobectomy and assessed easiness in interpretation by radiologists and thoracic surgeons with both techniques. METHODS: Patients scheduled for lobectomy for lung cancer were prospectively included and underwent CT for staging. A patient-specific three-dimensional model was generated and visualized in an augmented reality setting. One radiologist and one thoracic surgeon evaluated CT images and holograms to count lobar arteries, having as reference standard the number of arteries recorded at surgery. The easiness of vessel identification was graded according to a Likert scale. Wilcoxon signed-rank test and κ statistics were used. RESULTS: Fifty-two patients were prospectively included. The two doctors detected the same number of arteries in 44/52 images (85%) and in 51/52 holograms (98%). The mean difference between the number of artery branches detected by surgery and CT images was 0.31 ± 0.98, whereas it was 0.09 ± 0.37 between surgery and HGs (p = 0.433). In particular, the mean difference in the number of arteries detected in the upper lobes was 0.67 ± 1.08 between surgery and CT images and 0.17 ± 0.46 between surgery and holograms (p = 0.029). Both radiologist and surgeon showed a higher agreement for holograms (κ = 0.99) than for CT (κ = 0.81) and found holograms easier to evaluate than CTs (p < 0.001). CONCLUSIONS: Augmented reality by holograms is an effective tool for preoperative vascular anatomy assessment of lungs, especially when evaluating the upper lobes, more prone to anatomical variations. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04227444 RELEVANCE STATEMENT: Preoperative evaluation of the lung lobe arteries through augmented reality may help the thoracic surgeons to carefully plan a lobectomy, thus contributing to optimize patients' outcomes. KEY POINTS: • Preoperative assessment of the lung arteries may help surgical planning. • Lung artery detection by augmented reality was more accurate than that by CT images, particularly for the upper lobes. • The assessment of the lung arterial vessels was easier by using holograms than CT images.

Multidetector computed tomographic assessment of the normal diameters for the thoracic aorta and pulmonary arteries in infants and children.

BACKGROUND: Knowledge of the normal size of the thoracic aorta and pulmonary arteries is important regarding the detection of the abnormal and valuable in the treatment of patients with congenital and acquired cardiovascular diseases. PURPOSE: To determine the normal diameters of the thoracic vascular structures of pediatric participants on contrast-enhanced multidetector computer tomography (MDCT) scans. MATERIAL AND METHODS: Between July 2010 and July 2014, the MDCT examinations obtained from 520 participants (age range, 0-18 years; mean age, 8.49 years ± 5.54 [standard deviation]; male:female ratio, 1.6:1) with normal cardiovascular examinations were retrospectively evaluated. Patients were divided into six groups according to their age. Diameters of the ascending aorta (AA), descending aorta (DA), main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA) were measured. RESULTS: The diameters of the thoracic vascular structures increased with age and the statistical difference among the age groups and genders were significant. The vascular structures in male patients tended to have higher dimensions than female patients. The LPA demonstrated higher mean values than the RPA in each age group. The mean ratio PA (MPA/AA) is 0.93 ± 0.08 for pediatric participants and it is slightly higher in girls compared to boys (0.93 ± 0.07 and 0.92 ± 0.07, respectively). The level of pulmonary artery bifurcation moves caudally with increasing age with thoracal 6 vertebra being the most common for all age groups (53.3%). CONCLUSION: We believe that the results of our study can serve as a potential reference in differentiating the normal from the abnormal size of the aorta and pulmonary arteries on chest MDCT studies in the pediatric population.

Assessment of pulmonary artery pulse wave velocity in children: an MRI pilot study.

PURPOSE: To assess the feasibility of measuring pulmonary artery (PA) pulse wave velocity (PWV) in children breathing ambient air and 12% oxygen. METHODS: Velocity-encoded phase-contrast MR images of the PA were acquired in 15 children, aged 9-12years, without evidence of cardiac or pulmonary diseases. PWV was derived as the ratio of flow to area changes during early systole. Each child was scanned twice, in air and after at least 20minutes into inspiratory hypoxic challenge. Intra-observer and inter-observer variability and repeatability were also compared. RESULTS: PA PWV, which was successfully measured in all subjects, increased from 1.31±0.32m/s in air to 1.61±0.58m/s under hypoxic challenge (p=0.03). Intra- and inter-observer coefficients of variations were 9.0% and 15.6% respectively. Good correlation within and between observers of r=0.92 and r=0.72 respectively was noted for PA PWV measurements. Mean (95% limit of agreement) intra- and inter-observer agreement on Bland-Altman analysis were -0.02m/s (-0.41-0.38m/s) and -0.28m/s (-1.06-0.49m/s). CONCLUSION: PA PWV measurement in children using velocity-encoded MRI is feasible, reproducible and sufficiently sensitive to detect differences in PA compliance between normoxia and hypoxia. This technique can be used to detect early changes of PA compliance and monitor PAH in children.

Assessment of pulmonary artery morphology by optical coherence tomography.

Since its invention, optical coherence tomography (OCT) has been primarily used for the diagnosis of coronary artery disease. A few feasibility studies of OCT to visualise the pulmonary arteries were reported. However, OCT findings in the pulmonary arteries have not been validated using histology as the gold standard. To validate OCT findings for pulmonary arterial imaging, we selected 27 pulmonary arteries from 11 cadavers (6 males, 5 females, mean age 39.6 ± 21.3 years). Comparison of OCT images and histology was performed. Each histological sample was examined using three types of stains, and the quantified results were analysed by statistics. In conclusion, there was a strong correlation between histology and OCT measurements of the pulmonary arterial wall thickness, the pulmonary arterial wall has a single-layered structure with an average thickness of 0.162 mm. We propose that OCT is probably a useful tool of diagnosing pulmonary artery hypertension and may provide a means to study the pulmonary remodelling process.

Geometry and dimensions of the pulmonary artery bifurcation in children and adolescents: assessment in vivo by contrast-enhanced MR-angiography.

We sought to establish normal values for the diameters of the main (MPA), right (RPA), and left (LPA) pulmonary arteries and for the angles describing the geometry of the pulmonary artery bifurcation in children by using contrast-enhanced magnetic resonance angiography (CE-MRA). CE-MRA was performed in 69 children without cardiovascular disease. The median age was 10 ± 4.9 years (range 2-20), weight 37.4 ± 18.5 kg (10-82), body surface area (BSA) 1.18 ± 0.4 m(2) (0.48-2.07). The pulmonary artery diameters and angles were measured at standardized sites and projections. Regression analysis of diameters and angles in relation to BSA demonstrated linear relationship between the cross-sectional diameters of the pulmonary arteries and the square root of BSA (BSA(0.5)). Normalized mean diameters were for the MPA 17.6 ± 5.1 mm/m(2), origin of RPA 13.1 ± 2.9 mm/m(2), origin of LPA 14.2 ± 2.9 mm/m(2). The MPA showed a mean antero-posterior inclination of 33° ± 8° and a lateral leftward angulation of 18° ± 5°. The mean angle of the bifurcation was 99.5° ± 10.3°. Both side branches showed a supero-inferior course of the proximal segments, steeper for the RPA (7.7° ± 6.5°) than for the LPA (2.1° ± 7.8°). Normative curves in relation to BSA are presented for all measurements. This study provides normative values by CE-MRA for the main pulmonary artery and its side branches in children during somatic growth. These data can be used for identifying pulmonary arteries anomalies in children, and evaluate the need and the modality for treatment.

Preoperative assessment of the pulmonary artery by three-dimensional computed tomography before video-assisted thoracic surgery lobectomy.

OBJECTIVE: Our aim was to evaluate the efficacy of 3D imaging using multidetector row helical computed tomography (MDCT) in the preoperative assessment of the branching pattern of pulmonary artery (PA) before complete video-assisted thoracoscopic lobectomy (complete VATS lobectomy) for lung cancer. METHODS: Forty-nine consecutive patients with clinical stage I lung cancer scheduled for complete VATS lobectomy were evaluated about branching pattern of PA on 16-channel MDCT. Intraoperative finding of the PA branching pattern were compared with the 3D-CT angiography images obtained using MDCT. RESULTS: According to the intraoperative findings, 95.2% (139 of 146) of PA branches were precisely identified on preoperative 3D-CT angiography. All of the seven undetected branches were within 2mm in diameter. There was not a case that needed conversion to open thoracotomy because of intraoperative bleeding. CONCLUSION: A 3D-CT angiography using MDCT clearly revealed individual anatomies of pulmonary artery and could play an important role in safely facilitating complete VATS lobectomy procedure. However, we were unable to detect several thin branches with this technique. So, more care should be taken to avoid bleeding from these small vessels.

CT assessment of main pulmonary artery diameter.

PURPOSE: The purpose of this study was to determine the normal range of the main pulmonary artery diameter (MPAD) by computed tomography (CT) in persons with normal pulmonary artery pressure, and then to evaluate the relationship of the diameter with age, gender, and body surface area (BSA). MATERIALS AND METHODS: Between October 2005 and June 2007, among patients who had previously undergone a contrast-enhanced thorax CT scan, 112 persons (47 females, 65 males) without pulmonary pathology were selected for the study. All patients had normal mean pulmonary artery pressure. The widest diameter perpendicular to the long axis of the main pulmonary artery was measured at the pulmonary artery bifurcation level. The outer limits of the contrast were used to determine vessel diameter. RESULTS: Pulmonary artery diameters showed a homogeneous distribution; the CT-determined mean pulmonary artery diameter was 26.6 +/- 2.9 mm. The mean MPAD in males was 27 +/- 2.8 mm, and 25.9 +/- 3.0 mm in females. This difference was considered to be statistically significant (P = 0.048). There was a significant relationship between the MAPD and age and BSA (P = 0.043, P < 0.001). CONCLUSION: The present study demonstrated that in individuals with normal pulmonary artery pressure, the upper limit of the MPAD is 32.6 mm and that MPAD is wellcorrelated with BSA.

Noninvasive assessment of fetal pulmonary blood flow in experimental pulmonary hypertension in the fetal lamb.

The aim of this study was to assess pulmonary arterial blood flow changes induced by the creation of a systemic arteriovenous fistula (120 d gestation) in the fetal lamb using Doppler technique. Doppler echocardiographic assessment of the pulmonary artery blood flow performed 1, 6, and 14 d after surgery showed that mean pulmonary arterial blood flow in the left or right pulmonary artery was 224 +/- 58 mL/min at day 1 in the fistula group, significantly higher than in the control group (113 +/- 22 mL/min; p < 0.01, ANOVA test) whether no difference was found at days 6 and 14. The mean inner diameter of the left pulmonary artery measured on postmortem lung arteriograms compared favorably to the one measured on day 14 at the same level on ultrasound. The mean left pulmonary arterial blood flow, measured at birth on day 14 after surgery, using ultrasonic flow transducer, was not statistically different from the one measured by Doppler on day 14. Our data demonstrate that echocardiography allows accurate assessment of pulmonary arterial blood flow in utero, providing evidence suggesting transient high pulmonary blood flow that did not last >6 d after the creation of a systemic fistula.

Avaliaçäo do tamanho da artéria pulmonar após a operaçäo de derivaçäo cavopulmonar bidirecional / Assessment of size of pulmonary artery after bidirecional cavopulmonary operation

Este trabalho analisou as alteraçoes nos diâmetros da artéria pulmonar (AP) após a derivaçao cavopulmonar bilateral (DCPB). Foram incluídos 18 pacientes submetidos a DCPB, no período de março de 1990 a janeiro de 1997 que possuíam exames cineangiográficos disponíveis no período pré e pós-operatório. As medidas da APD e APE foram realizadas em três locais: na origem, imediatamente antes da bifurcaçao e no início da artéria do lobo inferior. Em seguida, os diâmetros de cada local foram indexados a superficie corpórea ou ao diâmetro da aorta, medido em nível do diafragma. Os dados angiográflcos e oximétricos foram submetidos à análise estatística. Quando analisados os diâmetros absolutos observou-se que a maioria sofreu um aumento nao-significante, no período pós-operatório, ao passo que o diâmetro H da APE apresentou uma diminuiçao. Os índices totais I e UI apresentaram diminuiçao significante, no período pós-operatório, e no índice total 11 a reduçao nao foi significante. A análise da variável seguimento pós-operatório demonstrou uma reduçao significativa dos índices totais nos pacientes com seguimento pós-operatório inferior a 23,6 meses. A presença de fluxo sanguíneo adicional determinou o aumento dos índices APD II e IH, e uma pequena reduçao nos outros índices. As medidas da AP indexadas pelo diâmetro da aorta revelou comportamento semelhante à indexaçao pela superfície corpórea. Na ausência de circulaçao venosa colateral (CVC) observou-se aumento significante da saturaçao de 02, por outro lado, a sua presença determinou um aumento nao-significante, durante o período de observaçao

Magnetic resonance assessment of the pulmonary arterial trunk anatomy, flow, pulsatility and distensibility.

We used magnetic resonance imaging with cine velocity mapping to study the anatomy of pulmonary bifurcation and to measure volume blood flow, pulsatility of flow and arterial wall distensibility in the central pulmonary arteries of nine healthy volunteers. Multislice, multiplane spin echo images were acquired to display pulmonary bifurcation anatomy. Diameters of the main pulmonary artery (MPA) in systole were 2.56 +/- 0.35 cm and in diastole 2.20 +/- 0.33 cm. Those of the right pulmonary artery (RPA) were 1.57 +/- 0.29 cm and 1.39 +/- 0.23 respectively, and of the left pulmonary artery (LPA) 1.79 +/- 0.26 cm and 1.55 +/- 0.10 cm respectively. A gradient echo sequence with phase shift velocity mapping was then used to measure flow in MPA, RPA and LPA 2 cm on either side of the pulmonary bifurcation. Time averaged flow, calculated from mean velocity and the cross-sectional area of the vessels was 4.99 +/- 1.10 l.min-1 in MPA, 2.23 +/- 0.58 l.min-1 in RPA and 2.31 +/- 0.63 l.min-1 in LPA. The pulsatility index of flow derived from peak forward flow, peak backward flow and time averaged flow were as follows: MPA 4.4 +/- 0.8, RPA 5.1 +/- 0.6 and LPA 4.6 +/- 1.5. Distensibility, calculated from the change in cross-sectional area between diastole and systole and expressed as percentage were as follows: MPA 25.6 +/- 10.7, RPA 21.4 +/- 10.7 and LPA 24.5 +/- 7.8. MRI with velocity mapping accurately characterized anatomy, flow, distensibility and pulsatility of the central pulmonary arteries.

Computer simulation of geometry and hemodynamics of canine pulmonary arteries.

Assuming that along the pulmonary arteries, mathematical expectations of branching are equal to matrix (Ei,j; i: parent branch class, j: daughter branch class number), we made computer drafts of patterns of pulmonary arterial branching trees from the published data of canine pulmonary arterial casts with the "Monte Carlo methods" by FORTRAN, calculating from these data, the numbers of branches, size and resistance of the trees. We also analyzed blood flow distribution in a pulmonary branch according to the pathlength from the entrance of the tree. The graphics of the trees were similar to the original arterial casts, and numbers of the branches were nearly the same as the previous reported values. Calculated resistance was reasonable. The rate of blood flow per unit vessel in the short pathlength group was calculated as 1.5 times that of the long pathlength group of the same diameter. We believe that our method of describing the branching pattern matrix (Ei,j) provides a reasonable simulation of complex branching patterns such as pulmonary arteries and a useful means to analyze local hemodynamics.

Assessment of right and left ventricular function in terms of force development with gestational age in the normal human fetus.

OBJECTIVE: To assess right and left ventricular systolic function in normal human fetuses by cross sectional Doppler echocardiography to calculate the force developed by myocardial shortening. DESIGN: Cross sectional echocardiographic images of the aorta and pulmonary arteries were obtained prospectively in order to measure great vessel diameters and calculate their cross sectional areas. Doppler velocity signals were recorded from the proximal aorta and the proximal pulmonary artery and digitised to obtain peak velocity, acceleration time, flow velocity time integral during acceleration, and the flow velocity time integral for the whole of ejection. Right and left ventricular force development was estimated by Newton's equation in which force is defined as the product of mass and acceleration. PATIENTS: 58 normal human fetuses at a gestational age of from 20 to 42 weeks. RESULTS: The cross sectional area of the pulmonary artery was 20% greater than that of the aorta. Aortic acceleration time was longer than that in the pulmonary artery, and peak blood flow velocity in the aorta was consistently greater than that in the pulmonary artery. Right ventricular stroke volume was significantly greater than left ventricular stroke volume. The force developed by the right and left ventricles was, however, similar throughout the gestational period studied, increasing tenfold from 20 weeks' gestation to term (r = 0.74, p less than 0.0001; r = 0.75, p less than 0.0001) respectively. CONCLUSION: The development of right and left ventricular force in the human fetus is similar in spite of the greater volume handled by the right ventricle. This index of ventricular performance does not require calculation of ventricular volume and because it varies independently of ventricular geometry and heart rate it should prove useful in assessing cardiac function in the normal human fetus and in fetuses with ventricular dysfunction.

[Quantitative assessment of the aorta and pulmonary artery in normal subjects (comparison of data from echocardiometric and morphometric studies)]. / Kolichestvennaia otsenka aorty i legochnoi arterii v norme (sopostavlenie dannykh ékhokardiometricheskogo i morfometricheskogo issledovanii).

Fifteen children whose age ranged from 5 to 15 years were examined by the method of two-dimensional echocardiography to calculate the quantitative characteristics of a normal aorta and pulmonary artery. To determine the character of correlation of these data with the findings of morphometric examination of the heart, the results were compared with the morphometric data in 21 children of the same age. The study showed that echocardiography makes it possible to calculate the size of the semilunar valves quite precisely. In standardization of the echocardiometric examination the parameters correlate well with the findings of morphometry, while the differences between them do not exceed 6-7%. It proved that the quantitative characteristics of the aorta and pulmonary artery were determined by the body surface area, but due to the non-linearity of their dependence on it, they change according to strictly specific patterns.

Cross sectional echocardiographic assessment of great artery diameters in infants and children.

The pulmonary trunk and aortic root were measured on cross sectional echocardiograms in 173 normal subjects aged from one day to 15 years. Fifteen neonates were reexamined 3-6 days later. The great vessels were visualised in the parasternal long axis and short axis views. All measurements were made in end diastole and end systole by the leading edge method. The internal diameter (inner surface to inner surface) of the pulmonary trunk was also measured. The diameters of the great vessels correlated best with the square root of body surface area. Individual variability in cardiac growth gave a wide scatter of normal values. This was controlled for by calculating the ratio of the pulmonary trunk to aortic root for each subject. This ratio showed little individual variability and, except for the neonatal period, was remarkably constant throughout infancy and childhood (1.06 (0.06)). In the first 24 hours of life the ratio of the pulmonary trunk to the aortic root was significantly larger (1.29 (0.12)) but within one week it decreased to the "normal" ratio found in the older age groups. These normal data should be useful in assessing patients with congenital heart disease, particularly those in whom pulmonary blood flow is abnormal.

Relation of branching angles to optimality for four cost principles.

The literature has suggested that branching angles depend on some principle of optimality. Most often cited are the minimization of lumen surface, volume, power and drag. The predicted angles depend on the principle applied, chi and alpha. Assuming flow o r chi, chi can be determined from r chi 0 = r chi 1 + r chi 2 when the radii of the parent (r0) major (r1) and minor (r2) daughters are known. The term alpha = r2/r1. Using different values for chi and alpha, we present graphs for the major and minor branching angles theta 1 and theta 2 and psi = theta 1 + theta 2 for each of the four optimization principles. Because psi is almost independent of alpha for values of chi and alpha found in 198 junctions taken from a human pulmonary artery, we are able to produce a plot of psi versus chi for each of the four principles on one graph. A junction can be provisionally classified as optimizing for a given principle if, knowing chi, the psi obs - psi pred is least for that principle. We find that this nomographic classification agrees almost perfectly with a previous classification based on a more exacting measure, the percent cost index I, where I = observed cost/minimum cost. We explain why this is to be expected in most but not all cases. First we generate a contoured percent cost surface of c = I - 100 around the optimally located junction, J, and superimpose a surface of equal angular deviations a = psi pred-psi obs. We find that c increases and a usually increases with distance from J as the actual junction moves along a straight line away from J. We then produce a plot of c versus a for two competing principles. A comparison of the principles demonstrates that, for most cases, a is smaller for the principle which has the smaller c value.

Suprasternal notch echocardiography. Assessment of its clinical utility in pediatric cardiology.

Echocardiographic suprasternal relationships of the transverse aortic arch (TAA), right pulmonary artery (RPA) and left atrium (Y' LAD) were validated and angiographic-echocardiographic measurement correlations were made for each structure. Normal values were determined with respect to body surface area. In normals, regardless of age or body size, mean dimensional TAA/RPA ratio was 1.2:1 and Y' LAD equaled the anterior-posterior, or Z axis, left atrial dimension (Z LAD)- TAA/RPA ratio was increased in aortic stenosis and tetralogy of Fallot and was decreased in ventricular septal defect, atrial septal defect and pulmonary stenosis. Ratio did not correlate with lesions severity as assessed by cardiac catheterization except in pulmonary stenosis. Discrepant Y' LAD values (usually increased Y' LAD and decreased Z LAD) occurred in children with various forms of heart disease. Some had sternal compression but others had normal chests. Children with pectus excavatum showed similar compression. These findings underscore the need for incorporation of a suprasternal examination into the standard echocardiographic examination of children.