Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.463
Filtrar
1.
J Appl Oral Sci ; 28: e20190145, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049132

RESUMO

OBJECTIVE: Ultrasonic wave technology is widely used during dental treatments. We previously demonstrated that this method protects the gingival tissue. However, the physiological change on the gingival microvasculature caused by this method remains unclear. The aim of this study was to investigate the relationship between the morphological and physiological effects on gingival microcirculation when preparing teeth, using the conventional dental turbine or ultrasonic method. METHODOLOGY: The lower premolar teeth of beagle dogs were prepared along the gingival margin by using a dental turbine or ultrasonic wave instrument. Gingival vasculature changes were investigated using scanning electron microscopy for corrosion resin casts. Gingival blood flow at the preparation site was determined simultaneously by laser Doppler flowmetry. These assessments were performed immediately (Day 0), at 7 days and 30 days after tooth preparation. RESULTS: At day 0, in the turbine group, blood vessels were destroyed and some resin leaked. Furthermore, gingival blood flow at the site was significantly increased. In contrast, the ultrasonic group demonstrated nearly normal vasculature and gingival blood flow similar to the non-prepared group for 30 days after preparation. No significant alterations occurred in gingival circulation 30 days after either preparation; however, the turbine group revealed obvious morphological changes. CONCLUSIONS: Based on multiple approach analyses, this study demonstrated that ultrasonic waves are useful for microvascular protection in tooth preparation. Compared with a dental turbine, ultrasonic wave instruments caused minimal damage to gingival microcirculation. Tooth preparation using ultrasonic wave instruments could be valuable for protecting periodontal tissue.


Assuntos
Gengiva/irrigação sanguínea , Microcirculação/fisiologia , Preparo do Dente/instrumentação , Ondas Ultrassônicas , Animais , Protocolos Clínicos , Instrumentos Odontológicos , Cães , Feminino , Humanos , Fluxometria por Laser-Doppler/métodos , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Fatores de Tempo , Preparo do Dente/métodos
2.
PLoS One ; 15(2): e0227488, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32012155

RESUMO

People suffering from glaucoma often endure high intra-ocular pressure (IOP). Methods for determining IOP either contact the eye or are unpleasant to some patients. There is therefore a need for a rapid and patient friendly non-contacting method to determine IOP. To address this need, we developed a tonometer prototype that employs spark-gap induced shock waves and a laser Doppler vibrometer (LDV) that reads the amplitude of membrane waves. The IOP was first identified from the membrane wave propagation velocity first in a custom-made ocular phantom and was then verified in ex vivo porcine eyes. The time-of-flight (TOF) of the membrane wave travelling on a hemispherical membrane was compared to reference IOP values in the sample obtained with an iCare TA01 tonometer. The shock front was characterized by high speed photography. Within one eye, the method achieved an agreement of 5 mmHg (1.96 standard deviation between the shock wave tonometer and the commercial manometer) and high method-to-method association (Pearson correlation, R2 = 0.98). The results indicate that the presented method could potentially be developed into a non-contacting technique for measuring IOP in vivo.


Assuntos
Glaucoma/diagnóstico , Fluxometria por Laser-Doppler/métodos , Hipertensão Ocular/diagnóstico , Tonometria Ocular/métodos , Animais , Olho/diagnóstico por imagem , Olho/fisiopatologia , Glaucoma/fisiopatologia , Humanos , Pressão Intraocular/fisiologia , Hipertensão Ocular/fisiopatologia , Fotografação , Estudos Prospectivos , Suínos
3.
Acta Odontol Scand ; 78(1): 31-37, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31349769

RESUMO

Objectives: To determine the baseline perfusion parameters of the alveolar mucosa using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) in healthy adults.Material and methods: Forty-two healthy adult subjects of either sex were tested. The perfusion of the alveolar mucosa was evaluated using a laser Doppler flowmetry and tissue spectrophotometry using O2C 'oxygen to see' device. The measurements encompassed the maxillary and mandibular mucosa at 20 different points.Results: The O2C device is a reliable method for noninvasive measurement of different perfusion parameters of the oral mucosa. The hemoglobin saturation values (So2 in %), as well as relative amount of hemoglobin in arbitrary units (AU) of the maxillary mucosa demonstrated lower values of that in the mandible. The flow value (AU) exhibited a significant difference in the posterior molar region only, while the velocity value (AU) showed a significant difference across all points except for the anterior region.Conclusion: the present study provides a set of brand-new perfusion parameters of the microcirculation of the alveolar mucosa using LDF-TS. The study suggests a variation of the perfusion parameters between the maxilla and the mandible. Differences in the anatomy of the blood supply, the thickness of the mucosa and the cortical bone, may be attributed to this variation. Further studies using different probes and a combination of ultrasonic measurements and SDF imaging will aid in giving a better overview of the perfusion in the oral mucosa.


Assuntos
Fluxometria por Laser-Doppler/métodos , Mandíbula/irrigação sanguínea , Maxila/irrigação sanguínea , Microcirculação/fisiologia , Mucosa Bucal/irrigação sanguínea , Oxigênio/fisiologia , Espectrofotometria/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Perfusão
5.
J Thorac Cardiovasc Surg ; 158(5): 1481-1488, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31358338

RESUMO

OBJECTIVE: The main therapeutic method of treatment for local hyperhidrosis is endoscopic thoracic sympathectomy. Generally, resections of the sympathetic trunk or ganglia are performed between the second rib and sixth rib. However, this procedure can result in compensatory sweating, in which excess sweating occurs on the back, chest, and abdomen. Compensatory sweating has been regarded as a thermoregulatory response and thought to be untreatable. This study suggests that compensatory sweating is not a physiologic reaction and is indeed treatable. METHODS: Eight patients with severe compensatory sweating were treated by observing blood perfusion of the skin with laser speckle flowgraphy, which determines the sympathetic nerves related to the area of skin with compensatory sweating. When intraoperative monitoring with laser speckle flowgraphy indicated the position of compensatory sweating by electrical stimulation of the sympathetic ganglion, ganglionectomy was performed. RESULTS: The skin domain that each sympathetic nerve controls was able to be detected by laser speckle flowgraphy. In all patients, compensatory sweating was resolved after interruption of the ganglia or sympathetic nerves related to compensatory sweating. CONCLUSIONS: Our results demonstrate that compensatory sweating is caused by denatured sympathetic nerves influenced by endoscopic thoracic sympathectomy and is not the result of a physiological response. With laser speckle flowgraphy, the sympathetic nerve related to the sweating of various parts of the body could be identified. The treatment of compensatory sweating on the back, chest, and stomach was previously considered to be difficult; however, compensatory sweating is demonstrated to be treatable with this technique.


Assuntos
Estimulação Elétrica/métodos , Hiperidrose , Monitorização Intraoperatória , Simpatectomia , Procedimentos Cirúrgicos Torácicos , Adulto , Endoscopia/efeitos adversos , Endoscopia/métodos , Feminino , Ganglionectomia/métodos , Humanos , Hiperidrose/diagnóstico , Hiperidrose/etiologia , Hiperidrose/fisiopatologia , Hiperidrose/terapia , Fluxometria por Laser-Doppler/métodos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/instrumentação , Monitorização Intraoperatória/métodos , Imagem de Perfusão/métodos , Glândulas Sudoríparas/inervação , Sudorese/fisiologia , Simpatectomia/efeitos adversos , Simpatectomia/métodos , Sistema Nervoso Simpático/cirurgia , Procedimentos Cirúrgicos Torácicos/efeitos adversos , Procedimentos Cirúrgicos Torácicos/métodos , Resultado do Tratamento
6.
Invest Ophthalmol Vis Sci ; 60(8): 3110-3118, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31323681

RESUMO

Purpose: Blood flow in the optic nerve head (ONH) is known to be reduced in eyes with advanced glaucoma. However, experimental results from non-human primates suggest an initial increase in ONH blood flow at the earliest stages of damage. This study assesses flow and pulsatile hemodynamics across a range of severities to test the hypothesis that this also occurs in human glaucoma. Methods: Laser speckle flowgraphy was used to measure average mean blur rate (MBRave) within ONH tissue (a correlate of capillary blood flow) and the pulsatile waveform in 93 eyes with functional loss and 74 glaucoma suspect/fellow eyes without functional loss. These were compared against results from 92 healthy control eyes. Parameters produced by the instrument's software were age-corrected, then compared between groups using generalized estimating equation models. Results: The mean MBRave in the control eyes was 12.5 units. In glaucoma suspect/fellow eyes, the mean was 16.4 units, higher with P < 0.0001. In eyes with functional loss, the mean was 13.8 units, lower than eyes without functional loss with P < 0.0001, although still higher than control eyes with P = 0.0096. Analysis of the pulsatile waveform suggested that the deceleration in flow as it approaches its maximum across the cardiac cycle was delayed in glaucoma. Conclusions: Blood flow within ONH capillaries was higher in glaucoma suspect eyes than in healthy controls. It was less elevated in eyes that had developed functional loss. The mechanisms causing these changes and their relation to concurrent changes in pulsatile hemodynamics remain under investigation.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Capilares/fisiopatologia , Glaucoma de Ângulo Aberto/fisiopatologia , Microcirculação/fisiologia , Disco Óptico/irrigação sanguínea , Fluxo Sanguíneo Regional/fisiologia , Adulto , Idoso , Capilares/diagnóstico por imagem , Feminino , Angiofluoresceinografia , Fundo de Olho , Glaucoma de Ângulo Aberto/diagnóstico , Humanos , Pressão Intraocular , Fluxometria por Laser-Doppler/métodos , Masculino , Pessoa de Meia-Idade , Prognóstico , Tomografia de Coerência Óptica/métodos
7.
PLoS One ; 14(6): e0218317, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31220141

RESUMO

Early detection of asymptomatic carotid stenosis may help identifying individuals at risk of stroke. We explore a new method based on laser Doppler vibrometry (LDV) which could allow the non-contact detection of stenosis from neck skin vibrations due to stenosis-induced flow disturbances. Experimental fluid dynamical tests were performed with water on a severely stenosed patient-specific carotid bifurcation model. Measurements were taken under various physiological flow regimes both in a compliant and stiff-walled version of the model, at 1 to 4 diameters downstream from the stenosis. An inter-arterial pressure catheter was positioned as reference. Increasing flow led to corresponding increase in power spectral density (PSD) of pressure and LDV recordings in the 0-500 Hz range. The stiff model lead to higher PSD. PSD of the LDV signal was less dependent on the downstream measurement location than pressure. The strength of the association between PSD and flow level, model material and measuring location was highest in the 0-50 Hz range, however useful information was found up to 200 Hz. This proof-of-concept suggests that LDV has the potential to detect stenosis-induced disturbed flow. Further computational and clinical validation studies are ongoing to assess the sensitivity and specificity of the technique for clinical screening.


Assuntos
Artérias Carótidas/diagnóstico por imagem , Estenose das Carótidas/diagnóstico , Fluxometria por Laser-Doppler/métodos , Pele/fisiopatologia , Angiografia/métodos , Pressão Arterial/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Artérias Carótidas/fisiopatologia , Estenose das Carótidas/fisiopatologia , Testes de Função Cardíaca/métodos , Humanos , Ultrassonografia Doppler/métodos , Vibração
8.
Plast Reconstr Surg ; 144(1): 124-133, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31246814

RESUMO

BACKGROUND: Free jejunal flaps are among the most commonly used flaps for esophageal reconstruction. However, ischemia-reperfusion injury caused by warm ischemia seen during transfer limits their use. Iloprost, a prostacyclin analogue, has been shown to reduce ischemia-reperfusion injury in various organs. The authors investigated tissue damage in jejunal flaps with iloprost and ischemic preconditioning and compared the effectiveness of these two modalities. METHODS: Thirty-four Sprague-Dawley rats were randomized into five groups: sham, ischemia-reperfusion (control), ischemic preconditioning, iloprost, and ischemic preconditioning plus iloprost. All flaps, except those in the sham group, underwent ischemia for 60 minutes and reperfusion for 2 hours. Flap perfusion was assessed by laser Doppler perfusion monitoring. Histologic sections were scored using the Chiu scoring system. Superoxide dismutase and myeloperoxidase levels were measured spectrophotometrically. RESULTS: Animals that were administered iloprost and/or underwent ischemic preconditioning had better postischemic recovery of mesenteric perfusion (ischemic preconditioning, 78 percent; iloprost, 83 percent; ischemic preconditioning plus iloprost, 90 percent; versus ischemia-reperfusion, 50 percent; p < 0.05). All intervention groups showed improved histology of jejunal flaps following ischemia-reperfusion injury (ischemic preconditioning, 3; iloprost, 2.3; ischemic preconditioning plus iloprost, 3.2; versus ischemia-reperfusion, 4.7; p < 0.01, p < 0.001, and p < 0.05, respectively). Superoxide dismutase levels were higher in ischemic preconditioning, iloprost plus ischemic preconditioning, and iloprost groups (ischemic preconditioning, 2.7 ± 0.2; ischemic preconditioning plus iloprost, 2.5 ± 0.3; versus ischemia-reperfusion, 1.2 ± 0.1; p < 0.01; iloprost, 2.4 ± 1.1; versus ischemia-reperfusion, 1.2 ± 0.1; p < 0.05). Myeloperoxidase, a marker for neutrophil infiltration, was lower in the iloprost group (iloprost, 222 ± 5; versus ischemia-reperfusion, 291 ± 25; p < 0.05). CONCLUSIONS: This study showed that both iloprost and ischemic preconditioning reduced reperfusion injury in jejunal flaps. Based on histologic results, iloprost may be a novel treatment alternative to ischemic preconditioning.


Assuntos
Retalhos de Tecido Biológico , Iloprosta/farmacologia , Precondicionamento Isquêmico/métodos , Jejuno/transplante , Inibidores da Agregação de Plaquetas/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Modelos Animais de Doenças , Esôfago/cirurgia , Fluxometria por Laser-Doppler/métodos , Masculino , Infiltração de Neutrófilos/efeitos dos fármacos , Peroxidase/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo
9.
Prog. obstet. ginecol. (Ed. impr.) ; 62(3): 260-265, mayo-jun. 2019. tab, graf
Artigo em Inglês | IBECS | ID: ibc-185008

RESUMO

Objective: To validate ultrasound criteria for prediction of severe preeclampsia based on the generation of appropriate reference values of the uterine artery pulsatility index according to gestational age and maternal age in a large sample of Peruvian women. Material and methods: We performed a retrospective study of 8,392 pregnant women attended in a level III maternal perinatal referral center in Peru between 2009 and 2016. The sample was randomly selected and divided into 2 groups: the study sample, in which reference curves of the mean uterine artery pulsatility index were constructed according to gestational age and at-risk maternal age (≤15 years and >35 years); and the validation sample, in which the criteria were validated. Multivariate analysis was applied, and the diagnostic and predictive value of the criteria were measured. Results: The area under the ROC curve was 0.61 (95%CI, 0.58-0.64) for the mean uterine artery pulsatility index, 0.66 (95%CI, 0.63-0.68) for values higher than its 95th percentile, and 0.60 (95%CI, 0.57-0.63) for at-risk maternal age. The combination of a value greater than the 95th percentile and at-risk maternal age generated a greater significant area (0.72 [95%CI, 0.688-0.742]) than the others separately. Conclusions: The mean uterine artery pulsatility index helps us to predict severe preeclampsia. However, the application of values above the 95th percentile combined with at-risk maternal age improved the identification of severe preeclampsia in our population, with a specificity of 99% and a positive predictive value of 89%


Objetivo: validar criterios de flujometría para predecir preeclampsia severa a partir de la elaboración de rangos refe-renciales propios del índice de pulsatilidad de la arteria uterina en función de la edad gestacional y su asociación a la edad materna, en una amplia muestra de la población peruana. Material y métodos: estudio retrospectivo en 8.392 gestantes atendidas en un centro de referencia nacional materno perinatal nivel III en Perú, entre el 2009 y 2016. La muestra fue seleccionada aleatoriamente y dividida en: muestra de elaboración para la construcción de curvas referenciales del índice de pulsatilidad promedio de las arterias uterinas según la edad gestacional y asociación con la edad materna de riesgo; y una segunda muestra para validación de los criterios. Se usó análisis multivariado, medición de la capacidad diagnóstica y predictiva de los criterios. Resultados: el área bajo la curva ROC para el índice de pulsatilidad promedio de las arterias uterinas fue 0,61 (IC95%=0,58-0,64), para valores mayores a su percentil 95 0,66 (IC95%=0,63-0,68), para la edad materna de riesgo 0,60 (IC95%=0,57-0,63). La asociación de un valor mayor al percentil 95 y edad materna de riesgo presento un área significativa mayor 0,72 (IC95%=0,688-0,742). Conclusiones: el índice de pulsatilidad promedio de las arterias uterinas ayuda a predecir la preeclampsia severa; sin embargo la aplicación de valores por encima del percentil 95 y asociado a la edad materna de riesgo mejora la identificación de preeclampsia severa con un 99% de especificidad y un valor predictivo positivo del 89% en nuestra población


Assuntos
Humanos , Feminino , Adolescente , Adulto Jovem , Adulto , Ultrassonografia Pré-Natal/métodos , Pré-Eclâmpsia/diagnóstico por imagem , Fluxometria por Laser-Doppler/métodos , Artéria Uterina/diagnóstico por imagem , Peru/epidemiologia , Valor Preditivo dos Testes , Diagnóstico Pré-Natal/métodos , Estudos Retrospectivos , Padrões de Referência , Fatores de Risco , Idade Materna
10.
Langenbecks Arch Surg ; 404(4): 505-515, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31055638

RESUMO

PURPOSE: Indocyanine green fluorescence angiography (ICG-FA) is an established technique for assessment of intestinal perfusion during gastrointestinal surgery, whereas quantitative ICG-FA (q-ICG) and laser speckle contrast imaging (LSCI) are relatively unproven. The study aimed to investigate whether the techniques could be applied interchangeably for perfusion assessment. METHODS: Nineteen pigs underwent laparotomy, two minor resections of the small bowel, and anastomoses. Additionally, seven pigs had parts of their stomach and small intestine de-vascularized. Data was also collected from an in vivo model (inferior caval vein measurements in two additional pigs) and an ex vivo flow model, allowing for standardization of experimental flow, distance, and angulation. Q-ICG and LSCI were performed, so that regions of interest were matched between the two modalities in the analyses, ensuring coverage of the same tissue. RESULTS: The overall correlation of q-ICG and LSCI evaluated in the porcine model was modest (rho = 0.45, p < 0.001), but high in tissue with low perfusion (rho = 0.74, p < 0.001). Flux values obtained by LSCI from the ex vivo flow model revealed a decreasing flux with linearly increasing distance as well as angulation to the model. The Q-ICG perfusion values obtained varied slightly with increasing distance as well as angulation to the model. CONCLUSIONS: Q-ICG and LSCI cannot be used interchangeably but may supplement each other. LSCI is profoundly affected by angulation and distance. In comparison, q-ICG is minimally affected by changing experimental conditions and is more readily applicable in minimally invasive surgery.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório , Angiofluoresceinografia , Intestino Delgado/irrigação sanguínea , Fluxometria por Laser-Doppler/métodos , Fluxo Sanguíneo Regional , Estômago/irrigação sanguínea , Procedimentos Cirúrgicos Vasculares , Animais , Velocidade do Fluxo Sanguíneo , Modelos Animais de Doenças , Intestino Delgado/diagnóstico por imagem , Intestino Delgado/cirurgia , Laparoscopia , Estômago/diagnóstico por imagem , Estômago/cirurgia , Suínos
11.
Methods Mol Biol ; 1947: 377-387, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30969429

RESUMO

A large body of evidence suggests that G protein-coupled receptors (GPCRs) play an important role in the regulation of peripheral vascular reactivity. Meanwhile, the extent of GPCR influence on the regulation of brain vascular reactivity, or cerebral blood flow (CBF), has yet to be fully appreciated. This is of physiological importance as the modulation of CBF depends on an intricate interplay between neurons, astrocytes, pericytes, and endothelial cells, all of which partaking in the formation of a functional entity referred to as the neurovascular unit (NVU). The NVU is the anatomical substrate of neurovascular coupling (NVC) mechanisms, whereby increased neuronal activity leads to increased blood flow to accommodate energy, oxygen, and nutrients demands. In light of growing evidence showing impaired NVC in several neurological disorders, and the fact that GPCRs represent the most important targets of FDA-approved drugs, it is of utmost importance to use experimental approaches to study GPCR-induced regulation of NVC for the future development of pharmaceutical compounds that could normalize CBF function. Herein, we describe a minimally invasive approach called laser Doppler flowmetry (LDF) that, when used in combination with a whisker stimulation paradigm in rodents, allows gauging blood perfusion in activated cerebral cortex. We comprehensively explain the surgical procedure and data acquisition in mice, and discussed about important experimental considerations for the study of CBF regulation by GPCRs using pharmacological agents.


Assuntos
Córtex Cerebral/irrigação sanguínea , Circulação Cerebrovascular , Fluxometria por Laser-Doppler/métodos , Receptores Acoplados a Proteínas-G/metabolismo , Animais , Camundongos , Ratos
12.
Clin Hemorheol Microcirc ; 72(3): 259-267, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30958335

RESUMO

The variation of blood flow characteristics caused by the probe pressure during noninvasive studies is of particular interest within the context of fundamental and applied research. It has been shown previously that the weak local pressure induces vasodilation, whereas the increased pressure is able to stop the blood flow in the compressed area, as well as to significantly change optical signals.The blood flow oscillations measured by laser Doppler flowmetry (LDF) characterize the functional state of the microvascular system and can be used for noninvasive diagnostics of its abnormality. This study was intended to identify the patterns of the relationship between the oscillating components of blood flow registered by the LDF method under different levels of pressure applied to an optical fiber probe.For this purpose, we have developed an original optical probe capable of regulating the applied pressure. The developed protocol included six sequential records of the blood perfusion at a pressure within the 0 to 200 mmHg range with unloading at the last stage.Using wavelet analyses, we traced the variation of energy of oscillations for these records in five frequency bands associated with different vascular tone regulation mechanisms. Six young volunteers of the same age (three males and three females) were included in this preliminary study and the protocol was repeated five times in each volunteer. Accordingly, 30 LDF records were available for the analyses. As expected, the LDF signal increases at weak pressure (30 mmHg) and decreases at increased pressure. The statistically stable amplification of endothelial associated blood flow oscillations under the 90 mmHg pressure allowed us to put forward a hypothesis that the endothelial activity increases. The possible causes of this phenomenon are discussed.


Assuntos
Hemodinâmica/fisiologia , Óptica e Fotônica/instrumentação , Pele/irrigação sanguínea , Adulto , Feminino , Humanos , Fluxometria por Laser-Doppler/métodos , Masculino , Pressão , Adulto Jovem
13.
Phys Med Biol ; 64(8): 085013, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30889552

RESUMO

The goal of this study was to demonstrate the feasibility of semi-automatic evaluation of cardiac Doppler indices in a single heartbeat in human hearts by performing 4D ultrafast echocardiography with a dedicated sequence of 4D simultaneous tissue and blood flow Doppler imaging. 4D echocardiography has the potential to improve the quantification of major cardiac indices by providing more reproducible and less user dependent measurements such as the quantification of left ventricle (LV) volume. The evaluation of Doppler indices, however, did not benefit yet from 4D echocardiography because of limited volume rates achieved in conventional volumetric color Doppler imaging but also because spectral Doppler estimation is still restricted to a single location. High volume rate (5200 volume s-1) transthoracic simultaneous tissue and blood flow Doppler acquisitions of three human LV were performed using a 4D ultrafast echocardiography scanner prototype during a single heartbeat. 4D color flow, 4D tissue Doppler cineloops and spectral Doppler at each voxel were computed. LV outflow tract, mitral inflow and basal inferoseptal locations were automatically detected. Doppler indices were derived at these locations and were compared against clinical 2D echocardiography. Blood flow Doppler indices E (early filling), A (atrial filling), E/A ratio, S (systolic ejection) and cardiac output were assessed on the three volunteers. Simultaneous tissue Doppler indices e' (mitral annular velocity peak), a' (late velocity peak), e'/a' ratio, s' (systolic annular velocity peak), E/e' ratio were also estimated. Standard deviations on three independent acquisitions were averaged over the indices and was found to be inferior to 4% and 8.5% for Doppler flow and tissue Doppler indices, respectively. Comparison against clinical 2D echocardiography gave a p  value larger than 0.05 in average indicating no significant differences. 4D ultrafast echocardiography can quantify the major cardiac Doppler indices in a single heart beat acquisition.


Assuntos
Ecocardiografia Doppler/métodos , Ecocardiografia Quadridimensional/métodos , Frequência Cardíaca , Fluxometria por Laser-Doppler/métodos , Fluxo Sanguíneo Regional , Velocidade do Fluxo Sanguíneo , Débito Cardíaco , Humanos , Função Ventricular Esquerda
14.
J Reconstr Microsurg ; 35(7): 489-498, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30836411

RESUMO

BACKGROUND: Success of free tissue transfer depends on standardized intraoperative flap design, microsurgical technique, and postoperative monitoring. We sought to investigate whether laser speckle imaging (LSI) is suitable for optimization of intraoperative flap design and postoperative monitoring of free flaps with skin paddles. METHODS: Skin perfusion was assessed with LSI in 27 free flaps after dissection at the donor site, after anastomosis at the recipient site, after inset and on postoperative days (POD) 1, 5, and 10. Skin perfusion of the whole flap (ROI [region of interest]-1) and the area over the pedicle (ROI-2) were compared between patients with and without postoperative complications (POC+ and POC - , respectively). A receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff for perfusion during LSI-guided microsurgery. RESULTS: In flaps without or only minor POC, intraoperatively measured perfusion over ROI-2 was significantly higher compared with ROI-1, whereas no significant differences were found for flaps with major POC. Perfusion of ROI-1 and 2 intraoperatively and on POD 1 was significantly lower in the POC+ compared with the POC- group (p < 0.05). ROC analysis yielded a threshold of 107 perfusion units (PU) at ROI-2 with an area under the curve (AUC) of > 0.8 for identification of flaps with major POC. CONCLUSION: LSI is an easy to use, noninvasive technique for identification of malperfused areas in free flaps, thus allowing for intraoperative decision-making on flap dimensions and postoperative monitoring. LSI therefore is a valuable tool for perfusion assessment with a high potential to become an established part of microsurgical practice.


Assuntos
Retalhos de Tecido Biológico/irrigação sanguínea , Complicações Intraoperatórias/diagnóstico , Fluxometria por Laser-Doppler/métodos , Complicações Pós-Operatórias/diagnóstico , Procedimentos Cirúrgicos Reconstrutivos/métodos , Adulto , Idoso , Anastomose Cirúrgica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Phys Med Biol ; 64(7): 07TR01, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30708364

RESUMO

Despite our understanding that the microvasculature plays a multifaceted role in the development and progression of various conditions, we know little about the extent of this involvement. A need exists for non-invasive, clinically meaningful imaging modalities capable of elucidating microvascular information to aid in our understanding of disease, and to aid in the diagnosis/monitoring of disease for more patient-specific care. In this review article, a number of imaging techniques are summarized that have been utilized to investigate the microvasculature of skin, along with their advantages, disadvantages and future perspectives in preclinical and clinical settings. These techniques include dermoscopy, capillaroscopy, Doppler sonography, laser Doppler flowmetry (LDF) and perfusion imaging, laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), including its Doppler and dynamic variant and the more recently developed OCT angiography (OCTA), photoacoustic imaging, and spatial frequency domain imaging (SFDI). Attention is largely, but not exclusively, placed on optical imaging modalities that use intrinsic optical signals to contrast the microvasculature. We conclude that whilst each imaging modality has been successful in filling a particular niche, there is no one, all-encompassing modality without inherent flaws. Therefore, the future of cutaneous microvascular imaging may lie in utilizing a multi-modal approach that will counter the disadvantages of individual systems to synergistically augment our imaging capabilities.


Assuntos
Microvasos/diagnóstico por imagem , Pele/diagnóstico por imagem , Angiografia/métodos , Humanos , Fluxometria por Laser-Doppler/métodos , Imagem de Perfusão/métodos , Pele/irrigação sanguínea , Tomografia de Coerência Óptica/métodos
16.
J Plast Reconstr Aesthet Surg ; 72(5): 771-777, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30711464

RESUMO

BACKGROUND: We evaluated the use of laser speckle contrast imaging (LSCI) in the perioperative planning in reconstructive flap surgery. The aim of the study was to investigate whether LSCI can predict regions with a high risk of developing postoperative necrosis. Our hypothesis was that, perioperatively, such regions have perfusion values below a threshold value and show a negative perfusion trend. METHODS: A porcine flap model based on the cranial gluteal artery perforator was used. Images were acquired before surgery, immediately after surgery (t = 0), after 30 min (t = 30 min), and after 72 h (t = 72 h). Regions of interest (ROIs) were chosen along the central axis of the flap. Clinical evaluation of the flap was made during each time point. RESULTS: At t = 72 h, a demarcation line could be seen at a distance of 15.8 ±â€¯0.4 cm away from the proximal border of the flaps. At t = 0, perfusion decreased gradually from the proximal to the distal ROI. At t = 30 min, perfusion was significantly lower in the ROI distal to the final demarcation line than that at t = 0, and in all flaps, these ROIs had a perfusion <25 PU. At t = 72 h, perfusion in the ROI proximal to this line returned to baseline levels, whereas perfusion in the distal ROI remained low. CONCLUSIONS: In our model, a decrease in perfusion during the first 30 min after surgery and a perfusion <25 PU at t = 30 min was a predictor for tissue morbidity 72 h after surgery, which indicates that LSCI is a promising technique for perioperative monitoring in reconstructive flap surgery.


Assuntos
Retalhos de Tecido Biológico/patologia , Fluxometria por Laser-Doppler/métodos , Animais , Modelos Animais de Doenças , Retalhos de Tecido Biológico/irrigação sanguínea , Necrose , Procedimentos Cirúrgicos Reconstrutivos/métodos , Suínos
17.
Ophthalmic Plast Reconstr Surg ; 35(4): 378-382, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30664573

RESUMO

PURPOSE: It has recently been shown that the flap pedicle does not supply blood to a tarsoconjunctival graft in the modified Hughes procedure in patients. This raises questions concerning the rate of revascularization of the free skin graft commonly used to reconstruct the anterior lamella. The aim of this study was, thus, to monitor the course of revascularization in free skin grafts overlying modified Hughes tarsoconjunctival flaps, using laser-based techniques. METHODS: Free skin grafts from the upper eyelid or upper arm in 9 patients were used to cover a tarsoconjunctival flap according to the modified Hughes procedure. Blood perfusion was monitored using laser speckle contrast imaging, and vascular reactivity was studied with laser Doppler velocimetry after heating the tissue to 44°C. Measurements were made at the time of surgery (baseline) and at 1, 3, 8, and 16 weeks postoperatively. RESULTS: The gradual increase in perfusion of the free skin grafts during the healing process indicates revascularization. A slight increase in perfusion was seen already after 1 week. Perfusion reached 50% of the baseline after 3 weeks, and complete restoration of perfusion was seen after 8 weeks. The vascular function monitored with heat-induced hyperemia increased in a similar fashion. CONCLUSIONS: Full-thickness skin grafts revascularize within 3 to 8 weeks, despite overlying a tarsoconjunctival flap, which has recently been reported to be avascular. This provides further evidence that it should be possible to repair large eyelid defects using free full-thickness eyelid grafts.


Assuntos
Blefaroplastia/métodos , Velocidade do Fluxo Sanguíneo/fisiologia , Túnica Conjuntiva/cirurgia , Neoplasias Palpebrais/cirurgia , Retalhos de Tecido Biológico/irrigação sanguínea , Fluxometria por Laser-Doppler/métodos , Transplante de Pele/métodos , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/diagnóstico , Carcinoma Basocelular/cirurgia , Neoplasias Palpebrais/diagnóstico , Pálpebras/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
18.
Surg Innov ; 26(3): 293-301, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30638132

RESUMO

BACKGROUND: The main limitation of perfusion assessment with indocyanine green fluorescence angiography during colorectal surgery is that the surgeon assesses the quality of perfusion subjectively. The ideal intestinal viability test must be minimally invasive, objective, and reproducible. We evaluated the quantitativity and reproducibility of laser speckle contrast imaging for perfusion assessment during colorectal surgery. METHODS: This was a prospective, nonrandomized, pilot study of 8 consecutive patients who underwent elective left-sided colorectal resection. Laser speckle perfusion images at the site of proximal transection of the bowel were obtained intraoperatively. We tested the hypothesis that laser speckle contrast imaging was able to quantitatively identify areas of diminished intestinal perfusion after devascularization and assessed the reproducibility of this method. RESULTS: All surgical procedures were uneventful and blood flow measurements were successfully made in all patients. None of the patients developed postoperative complications related to the anastomosis and stoma. Data analyses were successfully optimized to perform quantitative regional perfusion assessments in all cases. The bowel tissue blood flows of the anal side region adjacent to the transection line were significantly lower than those of the oral side region adjacent to the transection line after ligation of marginal vessels ( P = .012). Interrater reliability was high (intraclass correlation coefficients = 0.989), and a Bland-Altman plot showed few differences of mean flux data between 2 investigators. CONCLUSION: Laser speckle contrast imaging is feasible for real-time assessment of bowel perfusion with quantitativity and excellent reproducibility during colorectal surgery without administration of any contrast agents.


Assuntos
Neoplasias Colorretais/cirurgia , Intestinos/irrigação sanguínea , Período Intraoperatório , Fluxometria por Laser-Doppler/métodos , Imagem Óptica/métodos , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Fluxo Sanguíneo Regional
19.
Plast Reconstr Surg ; 143(2): 287e-292e, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30688880

RESUMO

Adequate tissue perfusion is essential to minimize postoperative complications following microsurgery. Intraoperative knowledge of tissue perfusion could aid surgical decision-making and result in reduced complications. Laser speckle imaging is a new, noninvasive technique for mapping tissue perfusion. This article discusses the feasibility of using laser speckle imaging during free flap breast reconstruction and its potential to identify areas of inadequate perfusion, thus reducing surgical complications. Adult patients scheduled to undergo free flap breast reconstruction were recruited into the study. Laser speckle images were obtained from the abdominal and breast areas at different stages intraoperatively. Zonal perfusion was compared with the Holm classification and clinical observations. Twenty patients scheduled to undergo free flap breast reconstruction were recruited (23 reconstructed breasts) (mean age, 50 years; range, 32 to 68 years). Flap zonal perfusion was 238 (187 to 313), 222 (120 to 265), 206 (120 to 265), and 125 (102 to 220) perfusion units for zones I, II, III, and IV, respectively (analysis of variance, p < 0.0001). Zonal area with perfusion below an arbitrary perfusion threshold were 20 (0.3 to 75), 41 (3 to 99), 49 (9 to 97), and 99 (25 to 100) percent, respectively (analysis of variance, p < 0.0001). One example is presented to illustrate potential intraoperative uses for laser speckle imaging. This study shows that laser speckle imaging is a feasible, noninvasive technique for intraoperative mapping of tissue perfusion during free flap breast reconstruction. Zonal tissue perfusion was reduced across the Holm classification. Observations indicated the potential for laser speckle imaging to provide additional information to augment surgical decision-making by detection of inadequate tissue perfusion. This highlights the opportunity for surgeons to consider additional aids for intraoperative tissue perfusion assessment to help reduce perfusion-related complications. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Diagnostic, IV.


Assuntos
Retalhos de Tecido Biológico/irrigação sanguínea , Interpretação de Imagem Assistida por Computador , Fluxometria por Laser-Doppler/métodos , Mamoplastia/métodos , Perfusão/métodos , Complicações Pós-Operatórias/prevenção & controle , Adulto , Idoso , Análise de Variância , Neoplasias da Mama/cirurgia , Estudos de Coortes , Estudos de Viabilidade , Feminino , Retalhos de Tecido Biológico/transplante , Humanos , Mastectomia/métodos , Microcirurgia/métodos , Pessoa de Meia-Idade , Monitorização Intraoperatória/métodos , Estatísticas não Paramétricas
20.
Plast Reconstr Surg ; 143(2): 398-404, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30688881

RESUMO

BACKGROUND: The breast and the factors that affect the sensitivity of the nipple-areola complex have been a significant subject of study in recent years. The main purpose of this study was to provide an objective assessment of the effect of volumetric differences on nipple-areola complex sensitivity. METHODS: Data were collected examining the right breast of 34 female volunteers. The mechanosensitive Aß-fiber and mechanoinsensitive C-fiber function of the nipple-areola complex was assessed after mechanical and chemical stimulation, respectively. Flare responses were elicited chemically by the application of histamine by means of iontophoresis and recorded by laser Doppler imaging. The correlation of the maximum flare area responses with the breast volume and nipple-areola complex and the response from the von Frey fiber test was estimated using linear regression analysis. RESULTS: Nipple-areola complex area increased with breast volume and, similarly, the area of histamine-induced axon reflex flare response follows the larger nipple-areola complex. However, a larger nipple-areola complex correlated with higher local mechanical thresholds. Higher mechanical thresholds were linked to smaller axon reflex area, suggesting combined small- and thick-fiber neuropathy. CONCLUSIONS: Objective small-fiber assessment using laser Doppler imaging and subjective mechanical threshold tests were used successfully to quantify function of Aß and C fibers in the nipple-areola complex. Increased breast volume was linked to larger nipples, but also to impairment of Aß and C fibers. Sensory testing can be incorporated into preoperative and postoperative management of patients undergoing breast operations to assess changes of neuronal function of the nipple-areola complex after surgery.


Assuntos
Mamilos/diagnóstico por imagem , Mamilos/inervação , Sensação/fisiologia , Limiar Sensorial , Adulto , Mama/inervação , Feminino , Voluntários Saudáveis , Humanos , Fluxometria por Laser-Doppler/métodos , Valores de Referência , Amostragem , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA