Multiyear Interval Changes in Aortic Wall Shear Stress in Patients with Bicuspid Aortic Valve Assessed by 4D Flow MRI

BACKGROUND

In patients with bicuspid aortic valve (BAV), 4D flow MRI can quantify regions exposed to abnormal aortic hemodynamics, including high wall shear stress (WSS), a known stimulus for arterial wall dysfunction. However, the long-term multiscan reproducibility of 4D flow MRI-derived hemodynamic parameters is unknown.

PURPOSE

To investigate the long-term stability of 4D flow MRI-derived peak velocity, WSS, and WSS-derived heatmaps in patients with BAV undergoing multiyear surveillance imaging.

STUDY TYPE

Retrospective.

POPULATION

20 BAV patients (mean age 48.4 ± 13.9 years; 14 males) with five 4D flow MRI scans, with intervals of at least 6 months between scans, and 125 controls (mean age: 50.7 ± 15.8 years; 67 males).

FIELD STRENGTH/SEQUENCE

1.5 and 3.0T, prospectively ECG and respiratory navigator-gated aortic 4D flow MRI.

ASSESSMENT

Automated AI-based 4D flow analysis pipelines were used for data preprocessing, aorta 3D segmentation, and quantification of ascending aorta (AAo) peak velocity, peak systolic WSS, and heatmap-derived relative area of elevated WSS compared to WSS ranges in age and sex-matched normative control populations. Growth rate was derived from the maximum AAo diameters measured on the first and fifth MRI scans.

STATISTICAL TESTS

One-way repeated measures analysis of variance. P < 0.05 indicated significance.

RESULTS

One hundred 4D flow MRI exams (five per patient) were analyzed. The mean total follow-up duration was 5.5 ± 1.1 years, and the average growth rate was 0.3 ± 0.2 mm/year. Peak velocity, peak systolic WSS, and relative area of elevated WSS did not change significantly over the follow-up period (P = 0.64, P = 0.69, and P = 0.35, respectively). The patterns and areas of elevated WSS demonstrated good reproducibility on semiquantitative assessment.

CONCLUSION

4D flow MRI-derived peak velocity, WSS, and WSS-derived heatmaps showed good multiyear and multiscan stability in BAV patients with low aortic growth rates. These findings underscore the reliability of these metrics in monitoring BAV patients for potential risk of dilation.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 1.

Valvular and ascending aortic hemodynamics of the On-X aortic valved conduit by same-day echocardiography and 4D flow MRI

This study aims to assess whether the On-X aortic valved conduit better restores normal valvular and ascending aortic hemodynamics than other commonly used bileaflet mechanical valved conduit prostheses from St. Jude Medical and Carbomedics by using same-day transthoracic echocardiography (TTE) and 4D flow magnetic resonance imaging (MRI) examinations. TTE and 4D flow MRI were performed back-to-back in 10 patients with On-X, six patients with St. Jude (two) and Carbomedics (four) prostheses, and 36 healthy volunteers. TTE evaluated valvular hemodynamic parameters: transvalvular peak velocity (TPV), mean and peak transvalvular pressure gradient (TPG), and effective orifice area (EOA). 4D flow MRI evaluated the peak systolic 3D viscous energy loss rate (VELR) density and mean vorticity magnitude in the ascending aorta (AAo). While higher TPV and mean and peak TPG were recorded in all patients compared to healthy subjects, the values in On-X patients were closer to those in healthy subjects (TPV 1.9 ± 0.3 vs. 2.2 ± 0.3 vs. 1.2 ± 0.2 m/s, mean TPG 7.4 ± 1.9 vs. 9.2 ± 2.3 vs. 3.1 ± 0.9 mmHg, peak TPG 15.3 ± 5.2 vs. 18.9 ± 5.2 vs. 6.1 ± 1.8 mmHg, p < 0.001). Likewise, while higher VELR density and mean vorticity magnitude were recorded in all patients than in healthy subjects, the values in On-X patients were closer to those in healthy subjects (VELR: 50.6 ± 20.1 vs. 89.8 ± 35.2 vs. 21.4 ± 9.2 W/m3, p < 0.001) and vorticity (147.6 ± 30.0 vs. 191.2 ± 26.0 vs. 84.6 ± 20.5 s-1, p < 0.001). This study demonstrates that the On-X aortic valved conduit may produce less aberrant hemodynamics in the AAo while maintaining similar valvular hemodynamics to St. Jude Medical and Carbomedics alternatives.

Impact of Holocene environmental change on the evolutionary ecology of an Arctic top predator

The Arctic is among the most climatically sensitive environments on Earth, and the disappearance of multiyear sea ice in the Arctic Ocean is predicted within decades. As apex predators, polar bears are sentinel species for addressing the impact of environmental variability on Arctic marine ecosystems. By integrating genomics, isotopic analysis, morphometrics, and ecological modeling, we investigate how Holocene environmental changes affected polar bears around Greenland. We uncover reductions in effective population size coinciding with increases in annual mean sea surface temperature, reduction in sea ice cover, declines in suitable habitat, and shifts in suitable habitat northward. Furthermore, we show that west and east Greenlandic polar bears are morphologically, and ecologically distinct, putatively driven by regional biotic and genetic differences. Together, we provide insights into the vulnerability of polar bears to environmental change and how the Arctic marine ecosystem plays a vital role in shaping the evolutionary and ecological trajectories of its inhabitants.

A classification approach to improve out of sample predictability of structure-based constitutive models for ascending thoracic aortic tissue

In this research, a pipeline was developed to assess the out-of-sample predictive capability of structure-based constitutive models of ascending aortic aneurysmal tissue. The hypothesis being tested is that a biomarker can help establish similarities among tissues sharing the same level of a quantifiable property, thus enabling the development of biomarker-specific constitutive models. Biomarker-specific averaged material models were constructed from biaxial mechanical tests of specimens that shared similar biomarker properties such as level of blood-wall shear stress or microfiber (elastin or collagen) degradation in the extracellular matrix. Using a cross-validation strategy commonly used in classification algorithms, biomarker-specific averaged material models were assessed in contrast to individual tissue mechanics of out of sample specimens that fell under the same category but did not contribute to the averaged model's generation. The normalized root means square errors (NRMSE) calculated on out-of-sample data were compared with average models when no categorization was performed versus biomarker-specific models and among different level of a biomarker. Different biomarker levels exhibited statistically different NRMSE when compared among each other, indicating more common features shared by the specimens belonging to the lower error groups. However, no specific biomarkers reached a significant difference when compared to the average model created when No Categorization was performed, possibly on account of unbalanced number of specimens. The method developed could allow for the screening of different biomarkers or combinations/interactions in a systematic manner leading the way to larger datasets and to more individualized constitutive approaches.

Global Aortic Pulse Wave Velocity is Unchanged in Bicuspid Aortopathy With Normal Valve Function but Elevated in Patients With Aortic Valve Stenosis: Insights From a 4D Flow MRI Study of 597 Subjects

BACKGROUND

Aortopathy is common with bicuspid aortic valve (BAV), and underlying intrinsic tissue abnormalities are believed causative. Valve-mediated hemodynamics are altered in BAV and may contribute to aortopathy and its progression. The contribution of intrinsic tissue defects versus altered hemodynamics to aortopathy progression is not known.

PURPOSE

To investigate relative contributions of tissue-innate versus hemodynamics in progression of BAV aortopathy.

STUDY TYPE

Retrospective.

SUBJECTS

Four hundred seventy-three patients with aortic dilatation (diameter ≥40 mm; comprised of 281 BAV with varied AS severity, 192 tricuspid aortic valve [TAV] without AS) and 124 healthy controls. Subjects were 19-91 years (141/24% female).

FIELD STRENGTH/SEQUENCE

1.5T, 3T; time-resolved gradient-echo 3D phase-contrast (4D flow) MRI.

ASSESSMENT

A surrogate measure for global aortic wall stiffness, pulse wave velocity (PWV), was quantified from MRI by standardized, automated technique based on through-plane flow cross-correlation maximization. Comparisons were made between BAV patients with aortic dilatation and varying aortic valve stenosis (AS) severity and healthy subjects and aortopathy patients with normal TAV.

STATISTICAL TESTS

Multivariable regression, analysis of covariance (ANCOVA), Tukey's, student's (t), Mann-Whitney (U) tests, were used with significance levels P < 0.05 or P < 0.01 for post-hoc Bonferroni-corrected t/U tests. Bland-Altman and ICC calculations were performed.

RESULTS

Multivariable regression showed age with the most significant association for increased PWV in all groups (increase 0.073-0.156 m/sec/year, R²  = 0.30-48). No significant differences in aortic PWV were observed between groups without AS (P = 0.20-0.99), nor were associations between PWV and regurgitation or Sievers type observed (P = 0.60, 0.31 respectively). In contrast, BAV AS patients demonstrated elevated PWV and a significant relationship for AS severity with increased PWV (covariate: age, R²  = 0.48). BAV and TAV patients showed no association between aortic diameter and PWV (P = 0.73).

DATA CONCLUSION

No significant PWV differences were observed between BAV patients with normal valve function and control groups. However, AS severity and age in BAV patients were directly associated with PWV increases.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

4D flow MRI derived aortic hemodynamics multi-year follow-up in repaired coarctation with bicuspid aortic valve

PURPOSE

The purpose of this study was to investigate the relationships between hemodynamic parameters and longitudinal changes in aortic dimensions on four-dimensional (4D) flow magnetic resonance imaging (MRI) in patients with bicuspid aortic valve (BAV) and repaired coarctation.

MATERIALS AND METHODS

The study retrospectively included patients with BAV and childhood coarctation repair who had at least two cardiothoracic MRI examinations including 4D flow MRI at baseline and follow-up. Analysis included the calculation of aortic peak velocities, wall shear stress (WSS), pulse wave velocity (PWV), aortic dimensions and annual growth rates. Differences between examinations were assessed using paired t-test or Wilcoxon signed rank test. Relationships between growth rate and 4D flow metrics were assessed using Pearson or Spearman correlation tests.

RESULTS

The cohort included 15 patients (mean age 35 ± 8 [SD] years, 9 men) with a median follow-up time of 3.98 years (Q1: 2.10; Q3: 4.96). There were no significant differences in aortic mean WSS, peak velocities, and PWV between baseline and follow-up values. Greater baseline peak velocities at the site of the coarctation were strongly associated with aortic narrowing (follow-up vs. baseline diameter) at coarctation zone (r = -0.64; P = 0.010) and moderately in descending aorta (r = -0.53; P = 0.042). In addition, increased baseline WSS in the aortic arch was strongly related with narrowing of the coarctation zone at follow-up (r = -0.64, P = 0.011).

CONCLUSION

Measures of aortic hemodynamics and aortic WSS are stable over time in patients with BAV with coarctation repair. Increased peak velocity was associated with a progressive narrowing at the site of the coarctation repair.

Aortic Pulse Wave Velocity Evaluated by 4D Flow MRI Across the Adult Lifespan

BACKGROUND

Evaluation of aortic stiffness by pulse wave velocity (PWV) across the adult lifespan is needed to better understand normal aging in women and men.

PURPOSE

To characterize PWV in the thoracic aorta using 4D flow MRI in an age- and sex-stratified cohort of healthy adults.

STUDY TYPE

Retrospective.

POPULATION

Ninety nine healthy participants (age: 46 ± 15 [19-79] years, 50% female), divided into young adults (<45 years) (N = 48), midlife (45-65 years) (N = 37), and later life (>65 years) (N = 14) groups.

FIELD STRENGTH/SEQUENCE

1.5 T or 3 T, 2D cine bSSFP, 4D flow MRI.

ASSESSMENT

Cardiac functional parameters of end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and myocardial mass were assessed by 2D cine bSSFP. PWV and aortic blood flow velocity were assessed by 4D flow MRI. Reproducibility of PWV was evaluated in a subset of nine participants.

STATISTICAL TESTS

Analysis of variance, Pearson's correlation coefficient (r), linear regression, intraclass correlation coefficient (ICC). A P value < 0.05 was considered statistically significant.

RESULTS

PWV increased significantly with age (young adults: 5.4 ± 0.9 m/sec, midlife: 7.2 ± 1.1 m/sec, and later life: 9.4 ± 1.8 m/sec) (r = 0.79, slope = 0.09 m/sec/year). PWV did not differ in women and men in entire sample (P = 0.40) or within age groups (young adults: P = 0.83, midlife: P = 0.17, and later life: P = 0.96). PWV was significantly correlated with EDV (r = -0.29), ESV (r = -0.23), SV (r = -0.28), myocardial mass (r = 0.21), and mean aortic blood flow velocity (r = -0.62). In the test-retest subgroup (N = 9), PWV was 6.7 ± 1.5 [4.4-9.3] m/sec and ICC = 0.75.

DATA CONCLUSION

4D flow MRI quantified higher aortic PWV with age, by approximately 1 m/sec per decade, and significant differences between young adults, midlife and later life. Reproducibility analysis showed good test-retest agreement. Increased PWV was associated with decline in cardiac function and reduced aortic blood flow velocity. This study demonstrates the utility of 4D flow MRI-derived aortic PWV for studying aging.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Polyphenols: Bioavailability, Microbiome Interactions and Cellular Effects on Health in Humans and Animals

Polyphenolic compounds have a variety of functions in plants including protecting them from a range of abiotic and biotic stresses such as pathogenic infections, ionising radiation and as signalling molecules. They are common constituents of human and animal diets, undergoing extensive metabolism by gut microbiota in many cases prior to entering circulation. They are linked to a range of positive health effects, including anti-oxidant, anti-inflammatory, antibiotic and disease-specific activities but the relationships between polyphenol bio-transformation products and their interactions in vivo are less well understood. Here we review the state of knowledge in this area, specifically what happens to dietary polyphenols after ingestion and how this is linked to health effects in humans and animals; paying particular attention to farm animals and pigs. We focus on the chemical transformation of polyphenols after ingestion, through microbial transformation, conjugation, absorption, entry into circulation and uptake by cells and tissues, focusing on recent findings in relation to bone. We review what is known about how these processes affect polyphenol bioactivity, highlighting gaps in knowledge. The implications of extending the use of polyphenols to treat specific pathogenic infections and other illnesses is explored.

Deep learning-based velocity antialiasing of 4D-flow MRI

Purpose

To develop a convolutional neural network (CNN) for the robust and fast correction of velocity aliasing in 4D‐flow MRI.

Methods

This study included 667 adult subjects with aortic 4D‐flow MRI data with existing velocity aliasing (n = 362) and no velocity aliasing (n = 305). Additionally, 10 controls received back‐to‐back 4D‐flow scans with systemically varied velocity‐encoding sensitivity (vencs) at 60, 100, and 175 cm/s. The no‐aliasing data sets were used to simulate velocity aliasing by reducing the venc to 40%–70% of the original, alongside a ground truth locating all aliased voxels (153 training, 152 testing). The 152 simulated and 362 existing aliasing data sets were used for testing and compared with a conventional velocity antialiasing algorithm. Dice scores were calculated to quantify CNN performance. For controls, the venc 175‐cm/s scans were used as the ground truth and compared with the CNN‐corrected venc 60 and 100 cm/s data sets

Results

The CNN required 176 ± 30 s to perform compared with 162 ± 14 s for the conventional algorithm. The CNN showed excellent performance for the simulated data compared with the conventional algorithm (median range of Dice scores CNN: [0.89–0.99], conventional algorithm: [0.84–0.94], p < 0.001, across all simulated vencs) and detected more aliased voxels in existing velocity aliasing data sets (median detected CNN: 159 voxels [31–605], conventional algorithm: 65 [7–417], p < 0.001). For controls, the CNN showed Dice scores of 0.98 [0.95–0.99] and 0.96 [0.87–0.99] for venc = 60 cm/s and 100 cm/s, respectively, while flow comparisons showed moderate‐excellent agreement.

Conclusion

Deep learning enabled fast and robust velocity anti‐aliasing in 4D‐flow MRI.

Divergence-Free Constrained Phase Unwrapping and Denoising for 4D Flow MRI Using Weighted Least-Squares

A novel divergence-free constrained phase unwrapping method was proposed and evaluated for 4D flow MRI. The unwrapped phase field was obtained by integrating the phase variations estimated from the wrapped phase data using weighted least-squares. The divergence-free constraint for incompressible blood flow was incorporated to regulate and denoise the resulting phase field. The proposed method was tested on synthetic phase data of left ventricular flow and in vitro 4D flow measurement of Poiseuille flow. The method was additionally applied to in vivo 4D flow measurements in the thoracic aorta from 30 human subjects. The performance of the proposed method was compared to the state-of-the-art 4D single-step Laplacian algorithm. The synthetic phase data were completely unwrapped by the proposed method for all the cases with velocity encoding (venc) as low as 20% of the maximum velocity and signal-to-noise ratio as low as 5. The in vitro Poiseuille flow data were completely unwrapped with a 60% increase in the velocity-to-noise ratio. For the in-vivo aortic datasets with venc ratio less than 0.4, the proposed method significantly improved the success rate by as much as 40% and reduced the velocity error levels by a factor of 10 compared to the state-of-the-art method. The divergence-free constrained method exhibits reliability and robustness on phase unwrapping and shows improved accuracy of velocity and hemodynamic quantities by unwrapping the low-venc 4D flow MRI data.

Segmentation of the Aorta and Pulmonary Arteries Based on 4D Flow MRI in the Pediatric Setting Using Fully Automated Multi-Site, Multi-Vendor, and Multi-Label Dense U-Net

BACKGROUND

Automated segmentation using convolutional neural networks (CNNs) have been developed using four-dimensional (4D) flow magnetic resonance imaging (MRI). To broaden usability for congenital heart disease (CHD), training with multi-institution data is necessary. However, the performance impact of heterogeneous multi-site and multi-vendor data on CNNs is unclear.

PURPOSE

To investigate multi-site CNN segmentation of 4D flow MRI for pediatric blood flow measurement.

STUDY TYPE

Retrospective.

POPULATION

A total of 174 subjects across two sites (female: 46%; N = 38 healthy controls, N = 136 CHD patients). Participants from site 1 (N = 100), site 2 (N = 74), and both sites (N = 174) were divided into subgroups to conduct 10-fold cross validation (10% for testing, 90% for training).

FIELD STRENGTH/SEQUENCE

3 T/1.5 T; retrospectively gated gradient recalled echo-based 4D flow MRI.

ASSESSMENT

Accuracy of the 3D CNN segmentations trained on data from single site (single-site CNNs) and data across both sites (multi-site CNN) were evaluated by geometrical similarity (Dice score, human segmentation as ground truth) and net flow quantification at the ascending aorta (Qs), main pulmonary artery (Qp), and their balance (Qp/Qs), between human observers, single-site and multi-site CNNs.

STATISTICAL TESTS

Kruskal-Wallis test, Wilcoxon rank-sum test, and Bland-Altman analysis. A P-value <0.05 was considered statistically significant.

RESULTS

No difference existed between single-site and multi-site CNNs for geometrical similarity in the aorta by Dice score (site 1: 0.916 vs. 0.915, P = 0.55; site 2: 0.906 vs. 0.904, P = 0.69) and for the pulmonary arteries (site 1: 0.894 vs. 0.895, P = 0.64; site 2: 0.870 vs. 0.869, P = 0.96). Qs site-1 medians were 51.0-51.3 mL/cycle (P = 0.81) and site-2 medians were 66.7-69.4 mL/cycle (P = 0.84). Qp site-1 medians were 46.8-48.0 mL/cycle (P = 0.97) and site-2 medians were 76.0-77.4 mL/cycle (P = 0.98). Qp/Qs site-1 medians were 0.87-0.88 (P = 0.97) and site-2 medians were 1.01-1.03 (P = 0.43). Bland-Altman analysis for flow quantification found equivalent performance.

DATA CONCLUSION

Multi-site CNN-based segmentation and blood flow measurement are feasible for pediatric 4D flow MRI and maintain performance of single-site CNNs.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Effect of age and sex on fully automated deep learning assessment of left ventricular function, volumes, and contours in cardiac magnetic resonance imaging

Deep learning algorithms for left ventricle (LV) segmentation are prone to bias towards the training dataset. This study assesses sex- and age-dependent performance differences when using deep learning for automatic LV segmentation. Retrospective analysis of 100 healthy subjects undergoing cardiac MRI from 2012 to 2018, with 10 men and women in the following age groups: 18-30, 31-40, 41-50, 51-60, and 61-80 years old. Subjects underwent 1.5 T, 2D CINE SSFP MRI. 35 pathologic cases from local clinical exams and the SCMR 2015 consensus contours dataset were also analyzed. A fully convolutional network (FCN) similar to U-Net trained on the U.K. Biobank was used to automatically segment LV endocardial and epicardial contours. FCN and manual segmentation were compared using Dice metrics and measurements of end-diastolic volume (EDV), end-systolic volume (ESV), mass (LVM), and ejection fraction (LVEF). Paired t-tests and linear regressions were used to analyze measurement differences with respect to sex and age. Dice metrics (median ± IQR) for n = 135 cases were 0.94 ± 0.04/0.87 ± 0.10 (ED endocardium/ES endocardium). Measurement biases (mean ± SD) among the healthy cohort were - 0.3 ± 10.1 mL for EDV, - 6.7 ± 9.6 mL for ESV, 4.6 ± 6.4% for LVEF, and - 2.2 ± 11.0 g for LVM; biases were independent of sex and age. Biases among the 35 pathologic cases were 0.1 ± 19 mL for EDV, - 4.8 ± 19 mL for ESV, 2.0 ± 7.6% for LVEF, and 1.0 ± 20 g for LVM. In conclusion, automatic segmentation by the Biobank-trained FCN was independent of age and sex. Improvements in end-systolic basal slice detection are needed to decrease bias and improve precision in ESV and LVEF.

Highly accelerated aortic 4D flow MRI using compressed sensing: Performance at different acceleration factors in patients with aortic disease

PURPOSE

To systematically assess the feasibility and performance of a highly accelerated compressed sensing (CS) 4D flow MRI framework at three different acceleration factors (R) for the quantification of aortic flow dynamics and wall shear stress (WSS) in patients with aortic disease.

METHODS

Twenty patients with aortic disease (58 ± 15 y old; 19 M) underwent four 4D flow scans: one conventional (GRAPPA, R = 2) and three CS 4D flows with R = 5.7, 7.7, and 10.2. All scans were acquired with otherwise equivalent imaging parameters on a 1.5T scanner. Peak-systolic velocity (V_max ), peak flow (Q_max ), and net flow (Q_net ) were quantified at the ascending aorta (AAo), arch, and descending aorta (DAo). WSS was calculated at six regions within the AAo and arch.

RESULTS

Mean scan times for the conventional and CS 4D flows with R = 5.7, 7.7, and 10.2 were 9:58 ± 2:58 min, 3:40 ± 1:19 min, 2:50 ± 0:56 min, and 2:05 ± 0:42 min, respectively. V_max , Q_max , and Q_net were significantly underestimated by all CS protocols (underestimation ≤ -7%, -9%, and -10% by CS, R = 5.7, 7.7, and 10.2, respectively). WSS measurements showed the highest underestimation by all CS protocols (underestimation ≤ -9%, -12%, and -14% by CS, R = 5.7, 7.7, and 10.2).

CONCLUSIONS

Highly accelerated aortic CS 4D flow at R = 5.7, 7.7, and 10.2 showed moderate agreement with the conventional 4D flow, despite systematically underestimating various hemodynamic parameters. The shortened scan time may enable the clinical translation of CS 4D flow, although potential hemodynamic underestimation should be considered when interpreting the results.

Chest radiograph at admission predicts early intubation among inpatient COVID-19 patients

Objective

The 2019 Coronavirus (COVID-19) results in a wide range of clinical severity and there remains a need for prognostic tools which identify patients at risk of rapid deterioration and who require critical care. Chest radiography (CXR) is routinely obtained at admission of COVID-19 patients. However, little is known regarding correlates between CXR severity and time to intubation. We hypothesize that the degree of opacification on CXR at time of admission independently predicts need and time to intubation.

Methods

In this retrospective cohort study, we reviewed COVID-19 patients who were admitted to an urban medical center during March 2020 that had a CXR performed on the day of admission. CXRs were divided into 12 lung zones and were assessed by two blinded thoracic radiologists. A COVID-19 opacification rating score (CORS) was generated by assigning one point for each lung zone in which an opacity was observed. Underlying comorbidities were abstracted and assessed for association.

Results

One hundred forty patients were included in this study and 47 (34%) patients required intubation during the admission. Patients with CORS ≥ 6 demonstrated significantly higher rates of early intubation within 48 h of admission and during the hospital stay (ORs 24 h, 19.8, p < 0.001; 48 h, 28.1, p < 0.001; intubation during hospital stay, 6.1, p < 0.0001). There was no significant correlation between CORS ≥ 6 and age, sex, BMI, or any underlying cardiac or pulmonary comorbidities.

Conclusions

CORS ≥ 6 at the time of admission predicts need for intubation, with significant increases in intubation at 24 and 48 h, independent of comorbidities.

Key Points

• Chest radiography at the time of admission independently predicts time to intubation within 48 h and during the hospital stay in COVID-19 patients.

• More opacities on chest radiography are associated with several fold increases in early mechanical ventilation among COVID-19 patients.

• Chest radiography is useful in identifying COVID-19 patients whom may rapidly deteriorate and help inform clinical management as well as hospital bed and ventilation allocation.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07354-y) contains supplementary material, which is available to authorized users.

Impact of age, sex, and global function on normal aortic hemodynamics

PURPOSE

To examine the effects of age, sex, and left ventricular global function on velocity, helicity, and 3D wall shear stress (3D-WSS) in the aorta of N = 100 healthy controls.

METHODS

Fifty female and 50 male volunteers with no history of cardiovascular disease, with 10 volunteers per age group (18-30, 31-40, 41-50, 51-60, and 61-80 years) underwent aortic 4D-flow MRI. Quantification of systolic aortic peak velocity, helicity, and 3D-WSS distribution and the calculation of age group-averaged peak systolic velocity and 3D-WSS maps ("atlases") were computed. Age-related and sex-related changes in peak velocity, helicity, and 3D-WSS were computed and correlated with standard metrics of left ventricular function derived from short-axis cine MRI.

RESULTS

No significant differences were found in peak systolic velocity or 3D-WSS based on sex except for the 18- to 30-year-old group (males 8% higher velocity volume and 3D-WSS surface area). Between successively older groups, systolic velocity decreased (13%, <1%, 7%, and 55% of the aorta volume) and 3D-WSS decreased (21%, 2%, 30%, and 62% of the aorta surface area). Mean velocity, mean 3D-3D-WSS, and median helicity increased with cardiac output (r = 0.27-0.43, all P < .01), and mean velocity and 3D-WSS decreased with increasing diameter (r > 0.35, P < .001). Arch and descending aorta systolic mean velocity, mean 3D-WSS, and median helicity increased with normalized left ventricular volumes: end diastolic volume (r = 0.31-0.37, P < .01), end systolic volume (r = 0.27-0.35, P < .01), and stroke volume (r = 0.28-0.35, P < .01).

CONCLUSION

Healthy aortic hemodynamics are dependent on subject age, and correlate with vessel diameter and cardiac function.

Differential Contributions of Actin and Myosin to the Physical Phenotypes and Invasion of Pancreatic Cancer Cells

INTRODUCTION

Metastasis is a fundamentally physical process in which cells deform through narrow gaps and generate forces to invade surrounding tissues. While it is commonly thought that increased cell deformability is an advantage for invading cells, we previously found that more invasive pancreatic ductal adenocarcinoma (PDAC) cells are stiffer than less invasive PDAC cells. Here we investigate potential mechanisms of the simultaneous increase in PDAC cell stiffness and invasion, focusing on the contributions of myosin II, Arp2/3, and formins.

METHOD

We measure cell invasion using a 3D scratch wound invasion assay and cell stiffness using atomic force microscopy (AFM). To determine the effects of actin- and myosin-mediated force generation on cell stiffness and invasion, we treat cells with pharmacologic inhibitors of myosin II (blebbistatin), Arp2/3 (CK-666), and formins (SMIFH2).

RESULTS

We find that the activity of myosin II, Arp2/3, and formins all contribute to the stiffness of PDAC cells. Interestingly, we find that the invasion of PDAC cell lines is differentially affected when the activity of myosin II, Arp2/3, or formins is inhibited, suggesting that despite having similar tissue origins, different PDAC cell lines may rely on different mechanisms for invasion.

CONCLUSIONS

These findings deepen our knowledge of the factors that regulate cancer cell mechanotype and invasion, and incite further studies to develop therapeutics that target multiple mechanisms of invasion for improved clinical benefit.

Four-dimensional Virtual Catheter: Noninvasive Assessment of Intra-aortic Hemodynamics in Bicuspid Aortic Valve Disease

Background Four-dimensional (4D) flow MRI enables the evaluation of blood flow alterations in patients with congenital bicuspid aortic valve (BAV). However, current analysis methods are cumbersome and lack the use of the volumetric data from 4D MRI. Purpose To investigate the feasibility and reproducibility of a technique that uses a catheter-like mathematical model (virtual catheter) to assess volumetric intra-aortic hemodynamics from 4D flow MRI in patients with BAV. Materials and Methods In this retrospective study, data were collected from adult patients with BAV and healthy participants who underwent aortic 4D flow MRI from November 2011 through August 2014. Reproducibility was tested in healthy study participants who underwent test-retest examinations within 2 weeks. Patients were grouped on the basis of the severity of aortic valve regurgitation (AVR) and aortic valve stenosis (AVS). A 4D virtual catheter mathematical model for probing intra-aortic hemodynamic flow was constructed as a tube with an automatically derived radius along the entire thoracic aorta centerline. Volumetric intra-aortic hemodynamics were computed from 4D flow MRI only within the virtual catheter, and the following volume-normalized systolic peaks were derived: kinetic energy (KE), viscous energy loss rate (VELR), and vorticity. Hemodynamic data were presented as medians with interquartile ranges and compared by using Mann-Whitney U test and Kruskal-Wallis test. Results The study included 91 participants (57 patients [mean age, 46 years ± 12], 18 women; 34 healthy participants [mean age: 44 years ± 14], 12 women; 15 healthy participants underwent test-retest examinations). Patients showed higher VELR values compared with healthy participants (median, 31 W/m³ [interquartile range, 21-72] vs 23 W/m³ [interquartile range, 17-30], respectively; P < .001) and vorticity (69 sec^-1 [interquartile range, 59-87] vs 60 sec^-1 [interquartile range, 50-67], respectively; P < .001). Four-dimensional virtual catheter showed differences among different AVS and AVR grades with the highest VELR (120 W/m³; interquartile range, 99-166; P < .001) and vorticity (108 sec^-1; interquartile range, 84-151; P < .001) found in severe AVS. High test-retest reproducibility was found for all virtual catheter-derived metrics (intraclass correlation, 0.80 ± 0.07; coefficient of variation, 9% ± 3). Conclusion The proposed four-dimensional (4D) virtual catheter technique enabled reproducible automated evaluation of volumetric intra-aortic hemodynamics alterations from 4D flow MRI in patients with bicuspid aortic valve. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Mitsouras and Hope in this issue.

Stiffness of pancreatic cancer cells is associated with increased invasive potential

Metastasis is a fundamentally physical process in which cells are required to deform through narrow gaps as they invade surrounding tissues and transit to distant sites. In many cancers, more invasive cells are more deformable than less invasive cells, but the extent to which mechanical phenotype, or mechanotype, can predict disease aggressiveness in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here we investigate the invasive potential and mechanical properties of immortalized PDAC cell lines derived from primary tumors and a secondary metastatic site, as well as noncancerous pancreatic ductal cells. To investigate how invasive behavior is associated with cell mechanotype, we flow cells through micron-scale pores using parallel microfiltration and microfluidic deformability cytometry; these results show that the ability of PDAC cells to passively transit through pores is only weakly correlated with their invasive potential. We also measure the Young's modulus of pancreatic ductal cells using atomic force microscopy, which reveals that there is a strong association between cell stiffness and invasive potential in PDAC cells. To determine the molecular origins of the variability in mechanotype across our PDAC cell lines, we analyze RNAseq data for genes that are known to regulate cell mechanotype. Our results show that vimentin, actin, and lamin A are among the most differentially expressed mechanoregulating genes across our panel of PDAC cell lines, as well as a cohort of 38 additional PDAC cell lines. We confirm levels of these proteins across our cell panel using immunoblotting, and find that levels of lamin A increase with both invasive potential and Young's modulus. Taken together, we find that stiffer PDAC cells are more invasive than more compliant cells, which challenges the paradigm that decreased cell stiffness is a hallmark of metastatic potential.

The physical origins of transit time measurements for rapid, single cell mechanotyping

The mechanical phenotype or 'mechanotype' of cells is emerging as a potential biomarker for cell types ranging from pluripotent stem cells to cancer cells. Using a microfluidic device, cell mechanotype can be rapidly analyzed by measuring the time required for cells to deform as they flow through constricted channels. While cells typically exhibit deformation timescales, or transit times, on the order of milliseconds to tens of seconds, transit times can span several orders of magnitude and vary from day to day within a population of single cells; this makes it challenging to characterize different cell samples based on transit time data. Here we investigate how variability in transit time measurements depends on both experimental factors and heterogeneity in physical properties across a population of single cells. We find that simultaneous transit events that occur across neighboring constrictions can alter transit time, but only significantly when more than 65% of channels in the parallel array are occluded. Variability in transit time measurements is also affected by the age of the device following plasma treatment, which could be attributed to changes in channel surface properties. We additionally investigate the role of variability in cell physical properties. Transit time depends on cell size; by binning transit time data for cells of similar diameters, we reduce measurement variability by 20%. To gain further insight into the effects of cell-to-cell differences in physical properties, we fabricate a panel of gel particles and oil droplets with tunable mechanical properties. We demonstrate that particles with homogeneous composition exhibit a marked reduction in transit time variability, suggesting that the width of transit time distributions reflects the degree of heterogeneity in subcellular structure and mechanical properties within a cell population. Our results also provide fundamental insight into the physical underpinnings of transit measurements: transit time depends strongly on particle elastic modulus, and weakly on viscosity and surface tension. Based on our findings, we present a comprehensive methodology for designing, analyzing, and reducing variability in transit time measurements; this should facilitate broader implementation of transit experiments for rapid mechanical phenotyping in basic research and clinical settings.

Fatty acid oxidation products ('green odour') released from perennial ryegrass following biotic and abiotic stress, potentially have antimicrobial properties against the rumen microbiota resulting in decreased biohydrogenation

AIMS

In this experiment, we investigated the effect of 'green odour' products typical of those released from fresh forage postabiotic and biotic stresses on the rumen microbiota and lipid metabolism.

METHODS AND RESULTS

Hydroperoxyoctadecatrienoic acid (HP), a combination of salicylic and jasmonic acid (T), and a combination of both (HPT) were incubated in vitro in the presence of freeze-dried ground silage and rumen fluid, under rumen-like conditions. 16S rRNA (16S cDNA) HaeIII-based terminal restriction fragment length polymorphism-based (T-RFLP) dendrograms, canonical analysis of principal coordinates graphs, peak number and Shanon-Weiner diversity indices show that HP, T and HPT likely had antimicrobial effects on the microbiota compared to control incubations. Following 6 h of in vitro incubation, 15.3% of 18:3n-3 and 4.4% of 18:2n-6 was biohydrogenated in control incubations, compared with 1.3, 9.4 and 8.3% of 18:3n-3 for HP, T and HPT treatments, respectively, with negligible 18:2n-6 biohydrogenation seen. T-RFLP peaks lost due to application of HP, T and HPT likely belonged to as yet uncultured bacteria within numerous genera.

CONCLUSIONS

Hydroperoxyoctadecatrienoic acid, T and HPT released due to plant stress potentially have an antimicrobial effect on the rumen microbiota, which may explain the decreased biohydrogenation in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

These data suggest that these volatile chemicals may be responsible for the higher summer n-3 content of bovine milk.

Once-daily budesonide inhalation suspension in infants and children < 4 and > or = 4 years of age with persistent asthma

BACKGROUND

Budesonide inhalation suspension (Pulmicort Respules; AstraZeneca LP, Wilmington, DE), a nebulized corticosteroid, was developed for use in infants and young children with persistent asthma.

OBJECTIVE

To compare the efficacy and safety of once-daily budesonide inhalation suspension in children < 4 years of age and in those > or = 4 years of age with persistent asthma.

METHODS

A retrospective analysis stratified by age group was performed on data from two randomized, double-blind, placebo-controlled, parallel-group studies that evaluated the efficacy and safety of budesonide inhalation suspension 0.25 mg, 0.5 mg, or 1.0 mg once daily for 12 weeks in children 6 months to 8 years of age with persistent asthma. Clinical assessments included nighttime and daytime asthma symptoms, breakthrough medication use, adverse events, and hypothalamic-pituitary-adrenal-axis function.

RESULTS

In both randomized studies, budesonide inhalation suspension demonstrated statistically significant improvement in nighttime and daytime asthma symptom scores compared with placebo. In the retrospective analysis of pooled data from these studies, the efficacy of budesonide was maintained when children were stratified by age group. Clinical improvements from baseline in nighttime and daytime asthma symptom scores were observed in both age groups at all budesonide inhalation suspension dose levels. No significant differences were observed between age groups in breakthrough medication use in any of the treatment groups. No differences were observed in the incidence of adverse events between the two age groups, and significant (P < 0.01) effect on hypothalamic-pituitary-adrenal-axis function was apparent only in children < 4 years of age at the 0.25-mg dose level.

CONCLUSIONS

Once-daily budesonide inhalation suspension is effective in the treatment of persistent asthma in children aged < 4 and > or = 4 years of age.

Exploration of factors that impact mode of death in the hemodialysis patient

The purpose of this quantitative and explorative qualitative study was to examine the illness trajectory, social integration, role change, and social support that may have influenced hemodialysis patients' mode of death. A quantitative archival medical record review recorded patients' mode of death as listed on the End Stage Renal Disease (ESRD) Death Notification form. Exploratory interviews were conducted with the deceased hemodialysis patient's significant other to explore patient's illness trajectory, end-of-life experiences, social integration, role change, and social support. Seventeen patients experienced a sudden, unexpected, unintentioned death, and 15 patients experienced an intentioned death after withdrawal of hemodialysis. Qualitative indicators of illness trajectory indicated either a fairly slow downward course with a sudden unintentioned death or a rapid downward spiraling course resulting in intentioned death after withdrawal of hemodialysis. While it was unknown if significant others would report of individuals withdrawing from treatment who lacked social integration or social support, findings suggest that some individuals in this study withdrawing from hemodialysis exercised their rights to self-determination and right to refuse life-saving treatments. Although findings of this study are not generalizable, it may be advisable for nurses to engage patients and family members in discussions regarding advance directives, rights to refuse treatment, and withdrawal from hemodialysis prior to a change in the patient's illness trajectory.

Short-term and long-term safety of budesonide inhalation suspension in infants and young children with persistent asthma

This article reviews the short-term and long-term safety profile of budesonide inhalation suspension (BIS) for nebulization in infants and young children with persistent asthma. Short-term safety (12 weeks) was assessed by pooling the results from the 3 randomized, double-blind, placebo-controlled, multicenter studies (studies A, B, and C) on the efficacy and safety of once- and twice-daily BIS. Long-term safety of BIS and conventional asthma therapy (CAT) was assessed in 52-week extension studies of the 12-week double-blind trials. CAT consisted of any available therapy for asthma; in 2 studies, CAT could have included treatment with inhaled glucocorticosteroids. Safety was assessed by monitoring adverse events (AEs), physical examinations, and basal and ACTH-stimulated plasma cortisol levels (in a subset of subjects). In the 52-week open-label extensions, the effects of BIS on growth velocity and skeletal age also were determined. In the 12-week studies, a total of 1017 subjects was evaluated for safety; totals of 231, 185, 229, 327, and 45 subjects were randomized to receive placebo or BIS at total daily doses of 0.25 mg, 0.5 mg, 1.0 mg, and 2.0 mg, respectively. Subject demographics and baseline asthma characteristics were similar across treatment groups, except that age, weight, height, and duration of asthma appeared higher in the 2. 0-mg daily dose group. For BIS groups, mean age was 58.9 months; mean weight was 20.3 kg; mean height was 108.9 cm, and mean duration of asthma was 3.2 years. There were no differences in the incidence, severity, or types of AEs reported among the BIS and placebo groups. There were no significant differences between placebo and BIS treatment groups in basal or ACTH-stimulated cortisol levels, physical examinations, clinical laboratory values, or fungal cultures. A total of 670 subjects completed the 52-week extension studies; 223 subjects received CAT and 447 received BIS. Median total daily doses of BIS ranged from 0.50 mg to 1.0 mg in the 3 studies, and the mean duration of treatment exposure was 304 +/- 119 days and 342 +/- 83 days in CAT and BIS groups, respectively. During the 52-week treatment period, the incidences of reported AEs were comparable between treatment groups and were mild-to-moderate in intensity; no new AEs occurred during the 52-week studies compared with 12-week studies. No significant differences were observed between BIS and CAT in basal or ACTH-stimulated cortisol levels, physical examinations, clinical laboratory values, or fungal cultures. There was a small but statistically significant reduction in growth velocity (a difference of 0.8 cm) in the BIS-treated group compared with the CAT group in study A. In studies B and C, growth velocity was not different between BIS and CAT groups. In pooled analyses, no statistically significant differences in growth velocity, standard median heights, or skeletal age were observed between BIS and CAT groups. Short-term and long-term treatment with BIS, over a wide range of doses, was well tolerated for the treatment of persistent asthma in infants and young children.

Caring for the orthopaedic patient receiving continuous ambulatory peritoneal dialysis

Providing nursing care for patients with End stage renal disease (ESRD) receiving continuous ambulatory peritoneal dialysis (CAPD) provides a variety of challenges for the orthopaedic nurse. In ESRD the kidneys not only lose the ability to remove waste products and excess fluids, but also are unable to assist the body to use active vitamin D3 for calcium absorption. ESRD patients are at a high risk for developing fractures due to the kidneys' inability to excrete phosphate, resulting in elevated plasma phosphate and low plasma calcium levels resulting in osteodystrophy. Patients conduct peritoneal dialysis treatments independently after receiving an in-depth education program. It is important for the nurse to continue to foster patients' independence by encouraging self-administration of CAPD even during hospitalization. CAPD is carried out manually by instilling dialysis solution into the peritoneal cavity usually four times daily to remove excess fluids and metabolic waste products. Orthopaedic nurses face the challenge of not only caring for the patient's orthopaedic injury but also ensuring CAPD is implemented correctly. This article outlines common problems experienced by ESRD patients, principles of CAPD, and expected nursing care.

A pharmacokinetic comparison of two oral liquid glucocorticoid formulations

To compare pharmacokinetics of liquid prednisolone and prednisone solutions and to assess relative bioavailability, six healthy adult men were administered 15 mg of each formulation. Blood samples were obtained and assayed for plasma prednisolone concentrations by high-performance liquid chromatography. Peak concentration was significantly higher with liquid prednisolone (mean +/- SD 430.3 +/- 62.5 vs 333.0 +/- 27.8 ng/ml, p = 0.013), with similar times to peak concentration. Prednisolone liquid gave higher concentrations at every time point (statistically significant for all except 0.25 hrs after the dose), resulting in a significantly greater total area under the curve (2029.8 +/- 246.9 vs 1633.3 +/- 221.1 ng/ml.hour, respectively, p = 0.002). Clearance was slower for prednisolone (128.3 +/- 15.1 vs 149.1 +/- 17.6 ml/min/1.73 m2, p = 0.01), and the relative bioavailability of the prednisolone liquid using prednisone liquid as the reference standard was 116 +/- 14%. Thus, prednisolone liquid has similar pharmacokinetic characteristics as prednisone liquid, with improved bioavailability.

Summertime haze air pollution and children with asthma

In order to investigate associations between summertime haze air pollution and asthma at an individual level, 52, 58, and 56 children (ages 7 to 13) attending a summer "asthma camp" were followed during the last week of June in 1991, 1992, and 1993, respectively. Most of the subjects had moderate to severe asthma. Daily records were kept of the environmental conditions, as well as of subject medication use, lung function, and medical symptoms. Air pollution was found to be significantly and consistently correlated with acute asthma exacerbations, chest symptoms, and lung function decrements. The pollutant most consistently associated with adverse health consequences was ozone (O3), although associations with sulfates and hydrogen ion suggest a possible role by fine particles as well. Effects were found to be roughly monotonic as a function of O3 concentration. Regression of morning (8:00 A.M.) to afternoon (5:00 P.M.) peak flow change on O3 indicated pulmonary function reductions similar to those previously reported for more active children without asthma. Moreover, analyses also indicated an increased risk of an asthma exacerbation and of experiencing chest symptoms of approximately 40% on the highest pollution day, relative to the mean. Based on these relative risk estimates, a rise in the 1-h daily maximal O3 from 84 ppb to 160 ppb was associated in this group with an increase from 20 to 28 (+/- 2) in the expected number of unscheduled medications administered/day, and from 29 to 41 (+/- 3) in the expected total number of chest symptoms/day. Thus, air pollution can be a major contributor to the respiratory problems experienced by children with asthma during the summer months.

Respiratory failure in children with acquired immunodeficiency syndrome and acquired immunodeficiency syndrome-related complex

Acute respiratory failure has a high mortality in patients with acquired immunodeficiency syndrome (AIDS). This study was undertaken to determine the etiology of acute respiratory failure and the outcome of children with AIDS and AIDS-related complex. Records of 31 children with AIDS or AIDS-related complex admitted to the pediatric intensive care unit for acute respiratory failure throughout a 46-month period were reviewed. Acute respiratory failure was due to Pneumocystis carinii pneumonia in 13, cytomegalovirus pneumonia in six, bacterial pneumonia in five, severe bacterial sepsis in four, Candida pneumonia in two, and a giant cell pneumonia in one patient. In addition, 11/19 patients with acute respiratory failure due to P carinii pneumonia or cytomegalovirus had superinfections with bacteria or Candida. Of the total of 19 primary and secondary bacterial infections, Pseudomonas aeruginosa was responsible in ten and Klebsiella pneumoniae in three children. Five children (16%) survived until pediatric intensive care unit discharge; three died within 6 months. The causes of acute respiratory failure were not significantly different in survivor and nonsurvivor groups. It is concluded that, in addition to P carinii pneumonia and cytomegalovirus pneumonia, bacterial infections (especially due to Pseudomonas and other Gram-negative organisms) are important causes of respiratory failure. The high mortality and grim ultimate prognosis seen may have implications for pediatricians attempting to identify the proper limits of medical intervention for this group of patients.

Use of the iced cystogram to differentiate bladder neck and external sphincter obstruction

An iced cystogram was done on 31 patients with neurogenic bladder and voiding dysfunction. We observed 5 distinguishable patterns upon which therapeutic measures to improve balance could be based. We found the iced cystogram to be a simple, inexpensive yet reliable technique to assess detrusor sphincter imbalance. With the information obtained from this study the therapeutic options were delineated more clearly and the results of the treatment were made more predictable.

Phenoxybenzamine in neurogenic bladder dysfunction after spinal cord injury. I. Voiding dysfunction

Phenoxybenzamine is a welcomed adjunct in the pharmacologic management of patients with neurogenic bladder dysfunction resulting from spinal cord trauma. Side effects are infrequent. Bladder balance was predictably and effectively achieved and maintained in patients with 1) lower motor neuron lesions, 2) upper motor neuron lesions and coexisting autonomic dysreflexia and 3) intact sympathetic innervation and upper motor neuron bladders. The response was unpredictable in patients with upper motor neuron lesions without coexisting dysreflexia.

Phenoxybenzamine in neurogenic bladder dysfunction after spinal cord injury. II. Autonomic dysreflexia

Phenoxybenzamine blockade of the alpha receptor site can abolish the vascular and internal sphincter responses in patients with chronic recurrent autonomic dysreflexia associated with bladder filling or contraction. The life-threatening hypertensive response is suppressed by this medication. Therefore, the drug is a beneficial adjunct in the pharmacologic management of autonomic dysreflexia. When the drug is used patients can be maintained free of a catheter. The drug had no serious side effects at the dose regimen used. One particularly significant advantage is its long duration of action--patients occasionally can skip doses of medication and not suffer acute symptoms.

Erections and sexual function in post-sphincterotomy bladder neck patients

A study of 131 patients who underwent sphincterotomy and bladder neck incision was done to determine changes in postoperative erectile and sexual function. A complete, permanent loss of erectile function was noted in 8.2 per cent of the patients and diminished erectile function was noted in 16.8 per cent. Unchanged or improved erections were noted in 74.8 per cent of the patients, while a complete loss of ability to engage in vaginal sexual intercourse, which had been present preoperatively, was sustained by 3.9 per cent of patients with diminished erections suffered no impairment of their preoperative sexual ability. Unaltered, improved or induced sexual function was present in 96.1 per cent of the patients postoperatively.

Salmonella infection and the genitourinary system

Six cases of severe salmonella genitourinary infection and a case of salmonella septicemia after prostatectomy are reported. The mechanism whereby the urinary tract is involved in salmonellosis is described, as are the different manifestations of genitourinary salmonellosis. Host factors predisposing to the development of genitourinary salmonella infection include other urologic pathology, malignant neoplasms and states of depressed immunity. Recommendations are made with regard to the diagnosis and management of this sometimes lethal condition.

Papillary adenocarcinoma of prostate

Papillary adenocarcinomas of the prostate are rare tumors which may arise from the prostatic ducts and the utricle; 2 cases are described. The diagnosis of these tumors is best established by cystourethroscopy and transurethral resection. The more common prostatic acinar adenocarcinoma is frequently associated with these tumors. The histopathologic recognition of papillary adenocarcinoma of the prostate and its differentiation from acinar adenocarcinoma is important since the natural history and response to treatment may be different.

Renal angiomyolipoma: two varieties

Two cases of symptomatic renal angiomyolipoma are presented, and their distinctive clinical, radiologic, and histologic features are discussed. In the first case the scout film demonstrated radiolucency of the tumor which helped to distinguish it from carcinoma. In the second case, which was associated with tuberous sclerosis, the renal lesion was large and unifocal, and the local lymph nodal involvement with tumor raised the possibility of malignant transformation.