Speckle Variance Photoacoustic Microscopy for Microhemodynamic Imaging.

Relying on the strong optical absorption of hemoglobin to pulsed laser energy, photoacoustic microscopy provides morphological and functional information on microvasculature label-freely. Here, we propose speckle variance photoacoustic microscopy (SV-PAM), which harnesses intrinsic imaging contrast from temporal-varied photoacoustic signals of moving red blood cells in blood vessels, for recovering three-dimension hemodynamic images down to capillary-level resolution within the microcirculatory tissue beds in vivo. Calculating the speckle variance of consecutive photoacoustic B-scan frames acquired at the same lateral position enables accurate identification of blood perfusion and occlusion, which provides interpretations of dynamic blood flow in the microvasculature, in addition to the microvascular anatomic structures. We demonstrate high-resolution hemodynamic imaging of vascular occlusion and reperfusion in the microvasculature of mice ears in vivo. The results suggest that our SV-PAM is potentially invaluable for biomedical hemodynamic investigations, for example, imaging ischemic stroke and hemorrhagic stroke.

Radiology: Cardiothoracic Imaging Highlights 2023.

Radiology: Cardiothoracic Imaging publishes novel research and technical developments in cardiac, thoracic, and vascular imaging. The journal published many innovative studies during 2023 and achieved an impact factor for the first time since its inaugural issue in 2019, with an impact factor of 7.0. The current review article, led by the Radiology: Cardiothoracic Imaging trainee editorial board, highlights the most impactful articles published in the journal between November 2022 and October 2023. The review encompasses various aspects of coronary CT, photon-counting detector CT, PET/MRI, cardiac MRI, congenital heart disease, vascular imaging, thoracic imaging, artificial intelligence, and health services research. Key highlights include the potential for photon-counting detector CT to reduce contrast media volumes, utility of combined PET/MRI in the evaluation of cardiac sarcoidosis, the prognostic value of left atrial late gadolinium enhancement at MRI in predicting incident atrial fibrillation, the utility of an artificial intelligence tool to optimize detection of incidental pulmonary embolism, and standardization of medical terminology for cardiac CT. Ongoing research and future directions include evaluation of novel PET tracers for assessment of myocardial fibrosis, deployment of AI tools in clinical cardiovascular imaging workflows, and growing awareness of the need to improve environmental sustainability in imaging. Keywords: Coronary CT, Photon-counting Detector CT, PET/MRI, Cardiac MRI, Congenital Heart Disease, Vascular Imaging, Thoracic Imaging, Artificial Intelligence, Health Services Research © RSNA, 2024.

Exertional calf pain at kilometer five - Finding the cause.

A 23-year-old professional distance runner with several years of exertional calf pain was diagnosed with a unique mixed type III and functional popliteal artery entrapment syndrome (PAES). Surgical reduction of the obstructing tissue allowed her to return to professional running. This case highlights the importance of including PAES in the differential for chronic intermittent lower extremity claudication and outlines the work-up required to diagnose this vascular obstruction in younger athletes.

Comparison of micro-CT image enhancement after use of different vascular casting agents.

Background: Microvascular visualization is crucial in understanding the mechanisms of several pathologies. For instance, visualization of the tumor microenvironment is important in understanding angiogenesis and role in cancer progression. Visualization would provide insights to cancer diagnosis, predicting metastatic growth, and evaluating therapeutic protocols. Similarly, understanding the microvascular network could be beneficial for study of degenerative diseases and tissue repair. The use of microscale computed tomography (micro-CT) and vascular casting agents provides high-resolution images of tissue vasculature in volumetric space. The purpose of this research was to compare a selection of commercially available contrast agents to determine the optimal solution for vascular visualization. Methods: A population of 16 female nude athymic mice (Charles Rivers Laboratories) were implanted with MDA-MB-231 breast cancer cells (ATCC) orthotopically in the lower left mammary fat pad to investigate the tumor microenvironment. Once tumors reach sufficient size, animals were equally divided into four groups based on the micro-CT agent to be administered, namely, control (no contrast agent), barium sulfate (BaSO4), Vascupaint, or Microfil. Animals were anesthetized prior to transcarotid micro-cannulation to infuse 2 mL of the specific contrast agent for intravascular distribution throughout the animal. The jugular vein on the other side of the carotid artery was opened to drain blood flow. Following successful perfusion, animals and extracted organs underwent high-resolution micro-CT scanning (OI/CT, MILabs). Images were reconstructed and analyzed using analysis software to extract mean intensity signals. Results: Preliminary post-mortem micro-CT results reveal Vascupaint and BaSO4 are useful for microvascular visualization. Both Vascupaint and BaSO4 produced significant contrast-enhanced micro-CT image enhancement in the brain (3.39±0.93 and 6.27±3.78, respectively) and kidney (12.85±1.98 and 32.87±10.03, respectively) as compared to Microfil (0.22±0.07 and 0.91±0.63, respectively; P<0.05). For the various contrast agents, there were no differences in image enhancement from the liver, spleen, or tumor tissue (P>0.21). Moreover, use of Vascupaint and BaSO4 allowed for visualization of smaller microvascular structures with average diameters of 20.54±4.15 and 25.82±3.75 µm, which were smaller compared to the 91.66±24.91 µm measurements from Microfil-enhanced micro-CT images (P<0.004). Conclusions: Our study suggests that the use of Vascupaint and BaSO4 is more than sufficient for ex vivo visualization of microvascular structures with contrast-enhanced micro-CT imaging as these contrast agents more effectively perfused smaller blood vessels.

Accuracy of maximal acceleration time of pedal arteries to diagnose critical limb-threatening ischemia.

INTRODUCTION: Maximal acceleration time of distal arteries of the foot (ATmax) is correlated to ankle-brachial index (ABI) and toe-brachial index (TBI), and seems very promising in diagnosing severe peripheral artery disease (PAD) and especially critical limb-threatening ischemia (CLTI). Our goal was to confirm the cut-off value of 215 ms to predict a toe pressure (TP) ⩽ 30 mmHg. METHODS: A 4-month retrospective study was conducted on patients addressed for suspicion of PAD. Demographic data, ABI, TBI, and Doppler ultrasound scanning parameters of the dorsal pedis and lateral plantar arteries (DPA and LPA) were recorded. RESULTS: A total of 137 patients with 258 lower limbs were included. ATmax was highly correlated to TBI (r = -0.89, p < 0.001). With the cut-off value of 215 ms, ATmax was effective to diagnose TP ⩽ 30 mmHg with a sensitivity of 93% [95% CI 77-99], a specificity of 96% [95% CI 92-98], a positive predictive value of 73% [95% CI 56-86], a negative predictive value of 99% [95% CI 97-100], and an area under the receiver operating characteristics curve of 0.99 [95% CI 0.98-1.00]. ATmax also showed promising results to rule out PAD in healthy patients. CONCLUSION: ATmax is a reliable diagnostic tool to diagnose low TP and could be a new easily performed hemodynamic criterion for diagnosis of CLTI.

Giant Cell Arteritis Presenting as Multiple Ischaemic Strokes: A Successful case of Endovascular Treatment.

Giant cell arteritis (GCA) may manifest with aggressive intracranial stenosis resistant to medical therapy, and patients may develop refractory neurologic deficits and cerebral infarcts, making GCA a life-threatening condition. We report the case of a 68-year-old woman recently diagnosed with GCA, medicated with prednisolone 60 mg daily. Two weeks later, the patient was admitted to our Stroke Unit after a sudden episode of global aphasia. Magnetic resonance angiography showed two recent ischaemic lesions, besides an erythrocyte sedimentation rate of 17 mm/hour. A cerebral angiography revealed bilateral stenosis and dilation in the petrous, cavernous and supraclinoid segments of internal carotid arteries (ICA). The patient was started on intravenous methylprednisolone pulses (250 mg daily for five days). Computed tomography (CT) angiography and Doppler ultrasound showed severe vascular disease affecting multiple territories, without significant intracranial involvement. The hypothesis of GCA with extracranial vasculitic involvement was considered as the aetiology of ischaemic cerebral infarctions in multiple territories and, given the severity of the disease, it was decided to add tocilizumab. Despite this, the patient evolved with significant worsening neurological deficits and a CT scan confirmed the presence of new vascular events. Endovascular treatment (EVT) with balloon angioplasty was conducted on both ICAs, with improved calibre and downstream filling. After that, the patient presented sustained clinical improvement, without recurrence of any ischaemic events at the one-year follow-up. This clinical case stands out for the importance of EVT as an effective therapy in patients with medically refractory GCA with symptomatic intracranial stenosis, improving their prognosis. LEARNING POINTS: Giant cell arteritis may manifest with aggressive and symptomatic intracranial arterial stenoses.Endovascular treatment is an effective intervention to prevent ischaemic complications in intracranial giant cell arteritis.

Primary thoracic aorta angiosarcoma presenting with thromboembolism and progressive claudication despite anticoagulation.

Primary aortic angiosarcomas (PAA) are rare angiosarcomas, frequently diagnosed in advanced stages due to initial misdiagnosis. This case describes a 66-year-old woman, initially presenting with a distal thoracic aorta thrombus and symptomatic bilateral popliteal emboli. Despite initial management and therapeutic anticoagulation, she experienced progressive lower limb claudication and 12 months following initial presentation she re-presented with an obstructing distal thoracic aorta mass and metastatic disease. Histopathology confirmed metastatic epithelioid angiosarcoma. Despite urgent palliative radiotherapy, she died 6 weeks after diagnosis from complications of tumour thromboembolism. Suspicion for PAA should be raised in the case of thrombus in atypical segments (e.g. thoracic aorta) or progressive course despite anticoagulation. Multimodal imaging including MRI and FDG-PET is useful to distinguish from benign aetiologies.

Methods, design, and initial results of an angiographic core lab from VOYAGER-PAD.

Background: Anatomy is critical in risk stratification and therapeutic decision making in coronary disease. The relationship between anatomy and outcomes is not well described in PAD. We sought to develop an angiographic core lab within the VOYAGER-PAD trial. The current report describes the methods of creating this core lab, its study population, and baseline anatomic variables. Methods: Patients undergoing lower-extremity revascularization for symptomatic PAD were randomized in VOYAGER-PAD. The median follow up was 2.25 years. Events were adjudicated by a blinded Clinical Endpoint Committee. Angiograms were collected from study participants; those with available angiograms formed this core lab cohort. Angiograms were scored for anatomic and flow characteristics by trained reviewers blinded to treatment. Ten percent of angiograms were evaluated independently by two reviewers; inter-rater agreement was assessed. Clinical characteristics and the treatment effect of rivaroxaban were compared between the core lab cohort and noncore lab participants. Anatomic data by segment were analyzed. Results: Of 6564 participants randomized in VOYAGER-PAD, catheter-based angiograms from 1666 patients were obtained for this core lab. Anatomic and flow characteristics were collected across 16 anatomic segments by 15 reviewers. Concordance between reviewers for anatomic and flow variables across segments was 90.5% (24,417/26,968). Clinical characteristics were similar between patients in the core lab and those not included. The effect of rivaroxaban on the primary efficacy and safety outcomes was also similar. Conclusions: The VOYAGER-PAD angiographic core lab provides an opportunity to correlate PAD anatomy with independently adjudicated outcomes and provide insights into therapy for PAD. (ClinicalTrials.gov Identifier: NCT02504216).

Low-velocity penetrating brain injury: a review of the literature and illustrative case.

INTRODUCTION: Low-velocity penetrating brain injury (LVPBI) is a class of brain injury where a foreign object violates the skull and damages the brain. Such injuries are rare and consequently understudied. CASE: As such, we report an illustrative case of a 29-year-old female with a dense, plastic spike penetrating her right orbit and into her midbrain. After assessment with a CT scan and angiography, the object was removed with careful attention to possible vascular injury. The patient had an uncomplicated post-operative course and received antibiotic and antiepileptic prophylaxis. She was discharged on post-operative day 5, experiencing only mild left-sided weakness. DISCUSSION: Common concerns regarding LVPBI include infection, post-traumatic epilepsy, and vascular injury. A review of published LVPBI cases over the past 20 years demonstrated that most cases (55.2%) are due to accidents. Of patients undergoing surgery, 43.4% underwent a craniotomy, and 22.8% underwent a craniectomy. Despite the grave nature of LVPBI, only 13.5% of the patients died. Additionally, 6.5% of patients developed an infection over their clinical course. CONCLUSION: In all, more reported cases further paint a picture of the current state of management and outcomes regarding LVPBI, paving the way for more cohesive guidelines to ensure the best possible patient outcomes.

Cardiovascular manifestations of Erdheim-Chester disease: A narrative review with two cases.

Erdheim-Chester disease (ECD) is a rare 'L' (Langerhans) group histiocytic neoplasm that affects a multitude of organ systems, causing osteosclerotic bone lesions, periaortic encasement ('coated' aorta), retroperitoneal fibrosis involving kidneys and ureters ('hairy kidney'), and infiltration of the central nervous system. Cardiovascular involvement can occur in up to 70% of patients and is usually found during computed tomography/magnetic resonance imaging evaluation. When present, cardiovascular symptoms can have wide variability in presentation from asymptomatic to pericarditis, fatal cardiac tamponade, myocardial infarction, conduction abnormalities, heart failure, renal artery stenosis, and claudication. Cardiac involvement found on imaging includes right atrial pseudotumor, right atrioventricular groove infiltration, and pericardial effusions. ECD can involve the large- and medium-sized arteries, often seen as periarterial thickening (commonly coating the aorta) with stenosis/occlusion. Although more cardiovascular ECD cases have begun to be published in the literature, more data are needed on the outcomes of these patients, as well as how cardiovascular manifestations respond to treatment of ECD.

A Phase 1 randomized, open-label clinical trial to evaluate the effect of a far-infrared emitting patch on local skin perfusion, microcirculation and oxygenation.

Far-infrared radiation (FIR) has been investigated for reduction of pain and improvement of dermal blood flow. The FIRTECH patch is a medical device designed to re-emit FIR radiated by the body. This phase 1 study was conducted to evaluate the local effects of the FIRTECH patch on local skin perfusion, microcirculation and oxygenation. This prospective, randomized, open-label, parallel designed study admitted 20 healthy participants to a medical research facility for treatment for 31 h on three anatomical locations. During treatment, imaging assessments consisting of laser speckle contrast imaging, near-infrared spectroscopy, side-stream dark-field microscopy, multispectral imaging and thermography were conducted regularly on patch-treated skin and contralateral non-treated skin. The primary endpoint was baseline perfusion increase during treatment on the upper back. Secondary endpoints included change in baseline perfusion, oxygen consumption and temperature of treated versus untreated areas. The primary endpoint was not statistically significantly different between treated and non-treated areas. The secondary endpoints baseline perfusion on the forearm (least square means [LSMs] difference 2.63 PU, 95% CI: 0.97, 4.28), oxygen consumption (LSMs difference: 0.42 arbitrary units [AUs], 95% CI: 0.04, 0.81) and skin temperature (LSMs difference 0.35°C, 95% CI: 0.16, 0.6) were statistically significantly higher in treated areas. Adverse events observed during the study were mild and transient. The vascular response to the FIRTECH patch was short-lived suggesting a non-thermal vasodilatory effect of the patch. The FIRTECH patch was well tolerated, with mild and transient adverse events observed during the study. These results support the therapeutic potential of FIR in future investigations.

Endovascular closure of a congenital extrahepatic portosystemic shunt for the treatment of hepatopulmonary syndrome in an infant.

Congenital portosystemic shunts may result in the development of hepatopulmonary syndrome, typically presenting with progressive hypoxemia in later childhood. We describe a case of a 5-month-old male with heterotaxy with polysplenia presenting with new onset hypoxemia. Subsequent evaluation identified an extrahepatic portosystemic shunt arising from the confluence of the main portal and superior mesenteric veins draining into the left renal vein. To treat his hypoxemia and prevent future complications of shunting, the patient underwent a successful single-stage endovascular closure.

In Vivo High-Contrast Biomedical Imaging in the Second Near-Infrared Window Using Ultrabright Rare-Earth Nanoparticles.

Intravital luminescence imaging in the second near-infrared window (NIR-II) enables noninvasive deep-tissue imaging with high spatiotemporal resolution of live mammals because of the properties of suppressed light scattering and diminished autofluorescence in the long-wavelength region. Herein, we present the synthesis of a downconversion luminescence rare-earth nanocrystal with a core-shell-shell structure (NaYF4@NaYbF4:Er,Ce@NaYF4:Ca). The structure efficiently maximized the doping concentration of the sensitizers and increased Er3+ luminescence while preventing cross relaxation. Furthermore, Ce3+ doping in the middle layer efficiently limited the upconversion pathway and increased downconversion by 24-fold to produce bright 1550 nm luminescence under 975 nm excitation. Finally, optimizing the inert shell coating of NaYF4:Ca and liposome encapsulation reduced the luminescence quenching impact by water and improved biological metabolism. Thus, our synthesized biocompatible, ultrabright NIR-II probes provide high contrast and resolution for through-scalp and through-skull luminescence imaging of mice cerebral vasculature without craniotomy as well as imaging of mouse hindlimb microvessels.

Anatomical and Three-Dimensional Study of the Female Feline Abdominal and Pelvic Vascular System Using Dissections, Computed Tomography Angiography and Magnetic Resonance Angiography.

This study describes the anatomical characteristics of the abdominal and pelvic vascular system of two healthy mature female cats via three-dimensional contrast enhanced computed tomography angiography, non-contrast enhanced magnetic resonance angiography and three-dimensional printing. Volume-rendering computed tomography angiography images were acquired from the ventral aspect using RadiAnt, Amira and OsiriX MD Dicom three-dimensional formats, and three-dimensional printing was obtained and compared with the corresponding computed tomography angiography images. Non-contrast enhanced magnetic resonance angiography was made using the time-of-flight imaging in ventral, oblique and lateral views. In addition, three cadavers with colored latex injection were dissected to facilitate the identification of the vascular structures. Three-dimensional computed tomography angiography showed the main vascular structures, whereas with the time-of-flight blood appeared with a high signal intensity compared with associated abdominal and pelvic tissues. Three-dimensional computed tomography angiography images and time-of-flight sequences provided adequate anatomical details of the main arteries and veins that could be used for future feline anatomical and clinical vascular studies of the abdomen and pelvis.

Signal-difference-to-noise comparison of temporal subtraction, kV-switching dual-energy and photon-counting dual-energy x-ray angiography.

BACKGROUND: Dual-energy (DE) x-ray angiography with photon-counting detectors (PCDs) may enable single-exposure DE imaging of coronary vasculature. PURPOSE: To compare the iodine signal-difference-to-noise ratio (SDNR) of single-exposure DE angiography with digital subtraction angiography (DSA) and kV-switching DE angiography for matched patient x-ray exposure. METHODS: In a phantom study, we determined the technique parameters that maximized the iodine SDNR per root entrance air kerma for DSA, kV-switching DE angiography and single-exposure DE angiography. We measured SDNR from images of a phantom consisting of an iodine step-wedge immersed in a water tank of either 20  or 30 cm in thickness. We also imaged a phantom with simulated vessels embedded in background clutter and measured vessel SDNR. For this second phantom, we also applied anti-correlated noise reduction (ACNR) and calculated the resulting iodine SDNR. All images were acquired using a cadmium telluride PCD with two energy bins and analog charge summing for charge sharing suppression. The energy-discrimination capabilities were only used for the single-exposure DE approach. Optimized techniques were compared in terms of SDNR per root air kerma for two levels of x-ray scatter. RESULTS: For the same patient x-ray exposure, the SDNR of single-exposure DE imaging without ACNR was 75% to 85% of that of kV-switching DE imaging (also without ACNR) and DSA, the latter two of which had nearly equal SDNR. The single-exposure DE approach required ∼50% of the tube load of the kV-switching approach to achieve the same SDNR. For matched patient air kermas, the single exposure approach required only ∼25% of the tube load of the kV-switching approach. ACNR increased SDNR by 2.4 and 3.0 for kV-switching and single-exposure DE imaging, respectively. CONCLUSIONS: Photon-counting, single-exposure DE angiography can suppress soft tissues and provide iodine SDNR levels comparable to DSA and kV-switching DE angiography for matched patient radiation exposures. When ACNR is used to reduce DE image noise, the SDNR of single-exposure DE imaging and kV-switching DE imaging exceed that of DSA by more than a factor of two. Compared to kV-switching DE imaging, single-exposure DE imaging requires substantially lower tube loading to achieve the same SDNR.

Contrast Agent-Free 3D Renal Ultrafast Doppler Imaging Reveals Vascular Dysfunction in Acute and Diabetic Kidney Diseases.

To combat the irreversible decline in renal function associated with kidney disease, it is essential to establish non-invasive biomarkers for assessing renal microcirculation. However, the limited resolution and/or vascular sensitivity of existing diagnostic imaging techniques hinders the visualization of complex cortical vessels. Here, a 3D renal ultrafast Doppler (UFD) imaging system that uses a high ultrasound frequency (18 MHz) and ultrahigh frame rate (1 KHz per slice) to scan the entire volume of a rat's kidney in vivo is demonstrated. The system, which can visualize the full 3D renal vascular branching pyramid at a resolution of 167 µm without any contrast agent, is used to chronically and noninvasively monitor kidneys with acute kidney injury (AKI, 3 days) and diabetic kidney disease (DKD, 8 weeks). Multiparametric UFD analyses (e.g., vessel volume occupancy (VVO), fractional moving blood volume (FMBV), vessel number density (VND), and vessel tortuosity (VT)) describe rapid vascular rarefaction from AKI and long-term vascular degeneration from DKD, while the renal pathogeneses are validated by in vitro blood serum testing and stained histopathology. This work demonstrates the potential of 3D renal UFD to offer valuable insights into assessing kidney perfusion levels for future research in diabetes and kidney transplantation.

Extending arterial stiffness assessment along the circumference using beam-steered ARFI and wave-tracking: A proof-of-principle study in phantoms and ex vivo.

Background: To fully quantify arterial wall and plaque stiffness, acoustic radiation force impulse (ARFI)-induced wave-tracking along the entire vessel circumference is desired. However, attenuation and guided wave behavior in thin vessel walls limits wave-tracking to short trajectories. This study investigated the potential of beam-steered ARFI and wave-tracking to extend group velocity estimation over a larger proportion of the circumference compared to conventional 0° ARFI-induced wave-tracking. Methods: Seven vessel-mimicking polyvinyl alcohol cryogel phantoms with various dimensions and compositions and an ex vivo human carotid artery were imaged in a dedicated setup. For every 20° phantom rotation, transverse group wave velocity measurements were performed with an Aixplorer Ultimate system and SL18-5 transducer using 0°/20°/-20°-angled ultrasound pushes. Transmural angular wave velocities were derived along 60°-trajectories. A 360°-angular velocity map was composed from the top-wall 60°-trajectories 0°-data, averaged over all physical phantom rotations (reference). For each phantom rotation, 360°-angular velocity maps were composed using 0°-data (0°-approach) or data from all angles (beam-steered approach). Percentages of rotations with visible waves and relative angular velocity errors compared to the reference map as function of the circumferential angle were determined for both approaches. Results: Reference 360°-angular velocity maps could be derived for all samples, representing their stiffness. Beam-steering decreased the proportion of the circumference where waves were untraceable by 20% in phantoms and 10% ex vivo, mainly at 0° push locations. Relative errors were similar for both approaches (phantoms: 10-15%, ex vivo: 15-35%). Conclusion: Beam-steering enables wave-tracking along a higher proportion of the wall circumference than 0° ARFI-induced wave-tracking.

Ocular and systemic associations and heritability of retinal arterial wall-to-lumen ratios in a twin cohort.

PURPOSE: To investigate ocular and systemic factors associated with the retinal arterial wall-to-lumen ratio (WLR) and to determine the relative contribution of genetic and environmental variation to WLR in healthy adults. METHODS: This cross-sectional twin study included 78 monozygotic and 67 dizygotic same-sex twin pairs aged 58.4 ± 9.8 (mean ± SD) years. Lumen diameter (LD) and outer diameter (OD) of a superotemporal retinal artery were measured using adaptive optics fundus photography, and the WLR was calculated. Linear mixed model regression analysis of associations with WLR comprised the descriptive variables ocular axial length (AL), intraocular pressure (IOP), height, weight, body mass index (BMI), smoking, blood pressure, high density (HDL), low density (LDL) and very low density (VLDL) lipoproteins, total cholesterol and triglycerides. The relative influence of genes and environment on WLR was calculated through polygenetic modelling. RESULTS: Increasing age and arterial blood pressure were associated with a higher WLR, while increasing retinal artery OD and ocular AL were associated with a lower WLR. Sex, smoking status, BMI, IOP, cholesterol levels or triglycerides had no detectable impact on the WLR. Broad-sense heritability of WLR was 21% (95% CI: 1-41%), while environmental factors accounted for the remaining 79% of the interindividual variance (95% CI: 59-99%). CONCLUSION: Retinal artery wall thickness was closely linked to increasing age and higher arterial blood pressure, the latter being mediated by the environment over genes.