Deep learning assisted classification of spectral photoacoustic imaging of carotid plaques.

Spectral photoacoustic imaging (sPAI) is an emerging modality that allows real-time, non-invasive, and radiation-free assessment of tissue, benefiting from their optical contrast. sPAI is ideal for morphology assessment in arterial plaques, where plaque composition provides relevant information on plaque progression and its vulnerability. However, since sPAI is affected by spectral coloring, general spectroscopy unmixing techniques cannot provide reliable identification of such complicated sample composition. In this study, we employ a convolutional neural network (CNN) for the classification of plaque composition using sPAI. For this study, nine carotid endarterectomy plaques were imaged and were then annotated and validated using multiple histological staining. Our results show that a CNN can effectively differentiate constituent regions within plaques without requiring fluence or spectra correction, with the potential to eventually support vulnerability assessment in plaques.

Blind spectral unmixing for characterization of plaque composition based on multispectral photoacoustic imaging.

To improve the assessment of carotid plaque vulnerability, a comprehensive characterization of their composition is paramount. Multispectral photoacoustic imaging (MSPAI) can provide plaque composition based on their absorption spectra. However, although various spectral unmixing methods have been developed to characterize different tissue constituents, plaque analysis remains a challenge since its composition is highly complex and diverse. In this study, we employed an adapted piecewise convex multiple-model endmember detection method to identify carotid plaque constituents. Additionally, we explore the selection of the imaging wavelengths in linear models by conditioning the coefficient matrix and its synergy with our unmixing approach. We verified our method using plaque mimicking phantoms and performed ex-vivo MSPAI on carotid endarterectomy samples in a spectral range from 500 to 1300 nm to identify the main spectral features of plaque materials for vulnerability assessment. After imaging, the samples were processed for histological analysis to validate the photoacoustic decomposition. Results show that our approach can perform spectral unmixing and classification of highly heterogeneous biological samples without requiring an extensive fluence correction, enabling the identification of relevant components to assess plaque vulnerability.

Multiperspective Photoacoustic Imaging Using Spatially Diverse CMUTs.

Photoacoustic imaging (PAI) is a promising technique to assess different constituents in tissue. In PAI, the propagating waves are low-amplitude, isotropic, and broadband. A common approach in PAI is the use of a single linear or curved piezoelectric transducer array to perform both PA and ultrasound imaging. These systems provide freedom, agility, and versatility for performing imaging, but have limited field of view (FOV) and directivity that degrade the final image quality. Capacitive micromachined ultrasonic transducers (CMUTs) have a great potential to be used for PAI since they provide larger bandwidth and better cost efficiency. In this study, to improve the FOV, resolution, and contrast, we propose a multiperspective PAI (MP-PAI) approach using multiple CMUTs on a flexible array with shared channels. The designed array was used to perform MP-PAI in an in vitro experiment using a plaque mimicking phantom where the images were compounded both incoherently and coherently. The MP-PAI approach showed a significant improvement in overall image quality. Using only three CMUTs led to about 20% increase in generalized-contrast-to-noise ratio (gCNR), 2-dB improvement in peak signal-to-noise ratio (PSNR), and double the structural coverage in comparison to a single CMUT setup. In numerical studies, the MP-PAI was thoroughly evaluated for both the coherent and incoherent compounding methods. The assessments showed that the image quality further improved for increased number of transducers and angular coverage. For 15 transducers, the improvement for resolution and contrast could be up to three times the amount in a single-perspective image. Nonetheless, the most prominent improvement of MP-PAI was its ability to resolve the structural information of the phantoms.

Maternal blood and hair manganese concentrations, fetal growth, and length of gestation in the ISA cohort in Costa Rica.

BACKGROUND: Animal studies have shown that both deficiency and excess manganese (Mn) may result in decreased fetal size and weight, but human studies have reported inconsistent results. METHODS: We examined the association of blood and hair Mn concentrations measured at different times during pregnancy with fetal growth among term births and length of gestation in a cohort of 380 mother-infant pairs living near banana plantations aerially sprayed with Mn-containing fungicides in Costa Rica. We used linear regression and generalized additive models to test for linear and nonlinear associations RESULTS: Mean (± SD) blood Mn concentration was 24.4 ± 6.6 µg/L and geometric mean (geometric SD) hair Mn concentration was 1.8 (3.2) µg/g. Hair Mn concentrations during the second and third trimesters of gestation were positively related to infant chest circumference (ß for 10-fold increase = 0.62 cm; 95% CI: 0.16, 1.08; and ß = 0.55 cm; 95% CI: -0.16, 1.26, respectively). Similarly, average maternal hair Mn concentrations during pregnancy were associated with increased chest circumference (ß for 10-fold increase = 1.19 cm; 95% CI: 0.43, 1.95) in infants whose mothers did not have gestational anemia, but not in infants of mothers who had gestational anemia (ß = 0.39 cm; 95% CI: -0.32, 1.10; pINT=0.14). All these associations were linear. Blood Mn concentrations did not show consistent linear nor nonlinear relationships with any of the birth outcomes CONCLUSIONS: Mn plays an important role in fetal development, but the extent to which environmental exposures may cause adverse health effects to the developing fetus is not well understood. Among women living near banana plantations in Costa Rica, we did not observe linear or nonlinear associations of Mn concentrations with lowered birth weight or head circumference, as reported in previous studies. However, we did find positive linear associations between maternal hair Mn concentrations during pregnancy and infant chest circumference.

Blood and hair manganese concentrations in pregnant women from the infants' environmental health study (ISA) in Costa Rica.

Manganese (Mn), an essential nutrient, is a neurotoxicant at high concentrations. We measured Mn concentrations in repeated blood and hair samples collected from 449 pregnant women living near banana plantations with extensive aerial spraying of Mn-containing fungicide mancozeb in Costa Rica, and examined environmental and lifestyle factors associated with these biomarkers. Mean blood Mn and geometric mean hair Mn concentrations were 24.4 µg/L (8.9-56.3) and 1.8 µg/g (0.05-53.3), respectively. Blood Mn concentrations were positively associated with gestational age at sampling (ß = 0.2; 95% CI: 0.1 to 0.2), number of household members (ß = 0.4; 95% CI: 0.1 to 0.6), and living in a house made of permeable and difficult-to-clean materials (ß = 2.6; 95% CI: 1.3 to 4.0); and inversely related to smoking (ß = -3.1; 95% CI: -5.8 to -0.3). Hair Mn concentrations were inversely associated with gestational age at sampling (% change = 0.8; 95% CI: -1.6 to 0.0); and positively associated with living within 50 m of a plantation (% change = 42.1; 95% CI: 14.2 to 76.9) and Mn concentrations in drinking water (% change = 17.5; 95% CI: 12.2 to 22.8). Our findings suggest that pregnant women living near banana plantations aerially sprayed with mancozeb may be environmentally exposed to Mn.

[Vasoconstriction is required for edema of contralateral lung after reperfusion injury of one lung]. / Edema pulmonar contralateral secundario al daño por isquemia-reperfusión de un pulmón. Papel de la vasoconstricción arterial pulmonar.

Ischemia-reperfusion (IR) lung injury is a significant cause of morbidity and mortality in certain clinical scenarios that include transplantation, thromboendarterectomy and reexpansion injury of the lung. Edema of the contralateral lung after IR injury of one lung has been reported and this study was aimed to clarify the pathophysiology of this phenomenon. One-lung ischemia/hypoxia followed by reperfusion with either blood or an acellular plasma substitute was achieved in an isolated rabbit lung model by hilum clamping. After reperfusion, we studied the isolated effects of vasoconstriction and inflammation on contralateral lung injury by using papaverine or hydrocortisone as vasodilator and anti-inflammatory, respectively. We observed that IR of one lung induces edema of the contralateral lung. Absence of leukocytes and platelets in the perfusate or use of hydrocortisone completely inhibits IR injury. Moreover, papaverine suppresses edema of the contralateral, but not that of the reperfused lung. We concluded that IR of one lung produces edema in the contralateral lung that requires vasoconstriction of the latter.

Edema pulmonar contralateral secundario al daño por isquemia-reperfusión de un pulmón: papel de la vasoconstricción arterial pulmonar / Vasoconstriction is required for edema of contralateral lung after reperfusion injury of one lung

El daño pulmonar por isquemia-reperfusión (IR) es una importante causa de morbilidad y mortalidad en ciertas condiciones clínicas que incluyen trasplantes, tromboendarterectomía y daño pulmonar por reexpansión. El edema pulmonar contralateral posterior al daño por IR de un pulmón ha sido reportado y esta investigación tiene como objetivo esclarecer la fisiopatología de dicho fenómeno. En un modelo de pulmones aislados y perfundidos de conejo, fue ocluido el hilio pulmonar de forma unilateral induciendo isquemia/hipoxia de dicho órgano, seguido de reperfusiones con sangre o con un substituto plasmático acelular. Los efectos aislados de vasoconstricción e inflamación en el daño pulmonar contralateral fueron estudiados posterior a la reperfusión, usando papaverina e hidrocortisona como agente vasodilatador y antiinflamatorio, respectivamente. En esta investigación se observó que la IR de un pulmón induce edema en el pulmón contralateral. La ausencia de leucocitos y plaquetas en la perfusión y el uso de hidrocortisona inhibió por completo el daño por IR. La papaverina suprimió el edema en el pulmón contralateral mas no en el reperfundido. Se concluye que la IR de un pulmón produce edema en el pulmón contralateral, para lo cual se requiere la presencia de vasoconstricción.

Ischemia-reperfusion (IR) lung injury is a significant cause of morbidity and mortality in certain clinical scenarios that include transplantation, thromboendarterectomy and reexpansion injury of the lung. Edema of the contralateral lung after IR injury of one lung has been reported and this study was aimed to clarify the pathophysiology of this phenomenon. One-lung ischemia/hypoxia followed by reperfusion with either blood or an acellular plasma substitute was achieved in an isolated rabbit lung model by hilum clamping. After reperfusion, we studied the isolated effects of vasoconstriction and inflammation on contralateral lung injury by using papaverine or hydrocortisone as vasodilator and anti-inflammatory, respectively. We observed that IR of one lung induces edema of the contralateral lung. Absence of leukocytes and platelets in the perfusate or use of hydrocortisone completely inhibits IR injury. Moreover, papaverine suppresses edema of the contralateral, but not that of the reperfused lung. We concluded that IR of one lung produces edema in the contralateral lung that requires vasoconstriction of the latter.