Blood Perfusion Data Research Articles

Facial thermal and blood perfusion patterns of human emotions: Proof-of-Concept

In this work, a preliminary study of proof-of-concept was conducted to evaluate the performance of the thermographic and blood perfusion data when emotions of positive and negative valence are applied, where the blood perfusion data are obtained from the thermographic data. The images were obtained for baseline, positive, and negative valence according to the protocol of the Geneva Affective Picture Database. Absolute and percentage differences of average values of the data between the valences and the baseline were calculated for different regions of interest (forehead, periorbital eyes, cheeks, nose and upper lips). For negative valence, a decrease in temperature and blood perfusion was observed in the regions of interest, and the effect was greater on the left side than on the right side. In positive valence, the temperature and blood perfusion increased in some cases, showing a complex pattern. The temperature and perfusion of the nose was reduced for both valences, which is indicative of the arousal dimension. The blood perfusion images were found to be greater contrast; the percentage differences in the blood perfusion images are greater than those obtained in thermographic images. Moreover, the blood perfusion images, and vasomotor answer are consistent, therefore, they can be a better biomarker than thermographic analysis in identifying emotions.

Analysis of Muscular Electrical Activity and Blood Perfusion of Upper Extremity in Patients with Hemiplegic Shoulder Pain: A Pilot Study.

Background Hemiplegic shoulder pain (HSP) is a common symptom for post-stroke patients, which has a severely adverse impact on their rehabilitation outcomes. However, the cause of HSP has not been clearly identified due to its complicated multifactorial etiologies. As possible causes of HSP, the abnormality of both muscular electrical activity and blood perfusion remains lack of investigations. Objective This study aimed to analyze the alteration of muscular electrical activity and blood perfusion of upper extremity in patients with HSP by using surface electromyography (sEMG) and laser speckle contrast imaging (LSCI) measurement techniques, which may provide some insight into the etiology of HSP. Methods In this observational and cross-sectional study, three groups of participants were recruited. They were hemiplegic patients with shoulder pain (HSP group), hemiplegic patients without shoulder pain (HNSP group), and healthy participants (Healthy group). The sEMG data and blood perfusion data were collected from all the subjects and used to compute three different physiological measures, the root-mean-square (RMS) and median-frequency (MDF) parameters of sEMG recordings, and the perfusion unit (PU) parameter of blood perfusion imaging. Results The RMS parameter of sEMG showed significant difference (p < 0.05) in the affected side between HSP, HNSP, and Healthy groups. The MDF parameter of sEMG and PU parameter of blood perfusion showed no significant difference in both sides among the three groups (p > 0.05). The RMS parameter of sEMG showed a statistically significant correlation with the pain intensity (r = -0.691, p =0.012). Conclusion This study indicated that the muscular electrical activity of upper extremity had a correlation with the presence of HSP, and the blood perfusion seemed to be no such correlation. The findings of the study suggested an alternative way to explore the mechanism and treatment of HSP.

Compromised resting cerebral metabolism after sport-related concussion: A calibrated MRI study

Altered resting cerebral blood flow (CBF0) in the acute phase post-concussion may contribute to neurobehavioral deficiencies, often reported weeks after the injury. However, in addition to changes in CBF0, little is known about other physiological mechanisms that may be disturbed within the cerebrovasculature. The aim of this study was to assess whether changes in baseline perfusion following sport-related concussion (SRC) were co-localized with changes in cerebral metabolic demand. Forty-two subjects (15 SRC patients 8.0 ± 4.6days post-injury and 27 age-matched healthy control athletes) were studied cross-sectionally. CBF0, cerebrovascular reactivity (CVR), resting oxygen extraction (OEF0) and cerebral metabolic rate of oxygen consumption (CMRO2|0) were measured using a combination of hypercapnic and hyperoxic breathing protocols, and the biophysical model developed in calibrated MRI. Blood oxygenation level dependent and perfusion data were acquired simultaneously using a dual-echo arterial spin labelling sequence. SRC patients showed significant decreases in CBF0 spread across the grey-matter (P < 0.05, corrected), and these differences were also confounded by the effects of baseline end-tidal CO2 (P < 0.0001). Lower perfusion was co-localized with reductions in regional CMRO2|0 (P = 0.006) post-SRC, despite finding no group-differences in OEF0 (P = 0.800). Higher CVR within voxels showing differences in CBF was also observed in the SRC group (P = 0.001), compared to controls. Reductions in metabolic demand despite no significant changes in OEF0 suggests that hypoperfusion post-SRC may reflect compromised metabolic function after the injury. These results provide novel insight about the possible pathophysiological mechanisms underlying concussion that may affect the clinical recovery of athletes after sport-related head injuries.

Clock drawing test in mild cognitive impairment: Correlation with cerebral perfusion in single-photon emission computed tomography.

This study aimed to understand the relationship between the Clock Drawing Test (CDT) and decreased blood flow in mild cognitive impairment (MCI) patients, using single-photon emission computed tomography. We characterized regional cerebral blood flow (rCBF) and the correlation with clinical variables and future conversion to dementia in 94 amnestic MCI patients. Blood perfusion data was correlated with the CDT (quantitative and qualitative scores) in order to evaluate their relationship and usefulness in predicting conversion to dementia. MCI patients displayed reduced rCBF in brain areas including the caudate nucleus; the frontal, parietal, and temporal lobes; as well as the cerebral cortex and cerebellum. The decrease in rCBF was higher for patients who later developed dementia. At baseline, CDT scores of these patients correlated with hypoperfusion in cortical and subcortical areas typically affected in Alzheimer's disease (AD) median 3 years before developing dementia. CDT total score was significantly correlated with rCBF in the left temporal lobe and the putamen; the analysis of rCBF in Brodmann areas showed significant correlations between the several clock elements (face, numbers, and hands), underlying qualitative errors (stimulus-bound response and conceptual deficit), and rCBF, most significantly in the left inferior temporal gyrus, posterior entorhinal cortex, posterior cingulate cortex, left parahippocampal cortex, and left inferior prefrontal gyrus. This study showed that a quantitative score and a qualitative assessment of clock drawing (error analysis) corresponded to dysfunction in AD key areas at an early stage, supporting the CDT utility in the detection of prodromal AD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Contrast-enhanced ultrasound analysis of tissue perfusion in tumor-bearing mice following treatment with endostatin combined with radiotherapy.

The aim of this study was to observe the effects of Endostar (recombinant human endostatin) and radiotherapy, singly or in combination, on blood flow in mouse tumour tissue using ultrasound imaging. The ultrasound contrast agent, SonoVue, was used for the contrast-enhanced ultrasound examinations. SonoLiver software was used to analyse dynamic vascular patterns (DVPs) in the contrast process. Blood perfusion data were collected and statistical analysis was performed for data processing. Results were presented as DVP curves and quantitative parameters. Quantitative parameters showed statistically significant (P<0.05) differences in peak strength, rise time, time to peak and mean transit time among the various treatment groups. Changes in tumour blood perfusion were quantified by the assessment of contrast-enhanced ultrasound parameters. The results indirectly reflected the degree of change in angiogenesis in the tumour following experimental intervention. Ultrasound contrast imaging effectively showed the extent of the changes in vascularity and flow state. Therefore, contrast-enhanced ultrasound is suitable for use as an indicator of blood flow changes in an experimental model.

Automated thermal face recognition based on minutiae extraction

In this paper, an efficient approach for human face recognition based on the use of minutiae points in thermal face image is proposed. The thermogram of human face is captured by thermal infra-red camera. Image processing methods are used to pre-process the captured thermogram, from which different physiological features based on blood perfusion data are extracted. Blood perfusion data are related to distribution of blood vessels under the face skin. In the present work, three different methods have been used to get the blood perfusion image, namely bit-plane slicing and medial axis transform, morphological erosion and medial axis transform, sobel edge operators. A five layer feed-forward back propagation neural network is used as the classification tool. It has been found that the first method supercedes the other two producing an accuracy of 97.62% with block size 16×16 for bit-plane 4.

Abstract 4235: Functional assessment of mouse tumor microenvironment following sunitinib treatment using an integrated micro-ultrasound and photoacoustic system

Abstract The development of novel cancer therapies could benefit significantly from the introduction of new functional imaging methods that allow non-invasive longitudinal assessment of tumor response to therapy. We have developed and tested a new instrument in which photoacoustic (PA) imaging is combined with co-registered micro-ultrasound (µUS). The new system allows tumor oxygenation and hemoglobin data derived from PA imaging to be combined with blood volume and perfusion data derived from contrast µUS and be observed during the course of therapy. Using this system, we assessed changes in the tumor microenvironment following treatment with an anti-angiogenic drug, sunitinib (Pfizer, USA). Human metastatic breast cancer cells (231/LM2-4) were surgically implanted in the mammary fat pads of 4 control and 7 treated female nude SCID mice and were allowed to grow for 10 days prior to initiation of experimental treatment, which consisted of either 4 consecutive daily gavage doses of 120mg/kg sunitinib, or control vehicle. Imaging was performed, using the VevoLAZR (VisualSonics, Canada) integrated µUS/PA system, prior to and following treatment. Tumor volume was quantified with 3D ultrasound imaging using a 40MHz frequency probe. Indices of relative blood volume and perfusion were quantified with non-linear contrast imaging using a 21MHz probe during a 50uL (2x109/mL) intravenous bolus injection of microbubbles (MicroMarker, VisualSonics). Blood oxygen saturation, relative tissue oxygen saturation, and hemoglobin concentration were measured with photoacoustic imaging using an integrated photoacoustic probe with 21MHz ultrasound frequency and tuneable 680-970nm laser optics. Following treatment, we observed significant (p&amp;lt;.05) suppression in tumor growth (-35%) decrease in blood volume (-91%), perfusion (-86%), relative tissue oxygen saturation (-60%), and hemoglobin concentration (-40%) in the sunitinib- relative to control-treated mice. When comparing pre- and post-treatment within the control group, there were increases in tumor volume (+120%), however, interestingly, there were also decreases in perfusion (-52%), blood volume (-22%) and relative tissue oxygen saturation (-31%). When comparing contrast µUS and PA data, there was a strong, moderate, and weaker correlations between relative tissue oxygen saturation and perfusion (R2 = 0.722), relative tissue oxygenation and blood volume (R2 = 0.576), and blood volume and hemoglobin concentration (R2 = 0.294) respectively. This study demonstrates the ability of an integrated PA and µUS imaging system to provide quantitative functional assessment of a preclinical breast cancer model following treatment with sunitinib. The degree to which quantitative correlates such as these are indicative of useful therapeutic response and of prognostic value remain to be investigated. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4235. doi:1538-7445.AM2012-4235

Minutiae Based Thermal Human Face Recognition using Label Connected Component Algorithm

In this paper, a thermal infra red face recognition system for human identification and verification using blood perfusion data and back propagation feed forward neural network is proposed. The system consists of three steps. At the very first step face region is cropped from the colour 24-bit input images. Secondly face features are extracted from the croped region, which will be taken as the input of the back propagation feed forward neural network in the third step and classification and recognition is carried out. The proposed approaches are tested on a number of human thermal infra red face images created at our own laboratory. Experimental results reveal the higher degree performance.

Skin heat transfer model of facial thermograms and its application in face recognition

It has been found that facial thermograms vary with ambient temperature, as well as other internal and external conditions, and result in severe decline in the facial recognition rate. To tackle this problem, a skin heat transfer (SHT) model based on thermal physiology is derived in this paper. The proposed model converts the facial thermograms into blood-perfusion data, which is revealed to reduce the within-class scatter of face images. The advantage of the derived blood-perfusion data over the raw thermograms for recognition is analyzed by the normalized reverse cumulative histogram. It is shown that blood-perfusion data are more consistent in representing facial features. The experiments conducted on both same-session and time-lapse data have further demonstrated that (1) the blood-perfusion data are less sensitive to ambient temperature, physiological and psychological conditions if the human bodies are in the steady state; (2) for time-lapse data, the performance with the blood-perfusion data is nearly identical to that of the same-session data, while the recognition rate with the temperature data dramatically decreases in this case. The major contributions of this work are the well-grounded infrared data preprocessing and the corresponding face recognition system.

Effect of forced-air heaters on perfusion and temperature distribution during and after open-heart surgery

After cardiopulmonary bypass, patients often show redistribution hypothermia, also called afterdrop. Forced-air blankets help to reduce afterdrop. This study explores the effect of forced-air blankets on temperature distribution and peripheral perfusion. The blood perfusion data is used to explain the observed temperature effects and the reduction of the afterdrop. Fifteen patients were enrolled in a randomised study. In the test group (n=8), forced-air warmers were used. In the control group (n=7), only passive insulation was used. Core and skin temperatures and thigh temperatures at 0, 8, 18 and 38 mm depth were measured. Laser Doppler flowmetry (LDF) was used to record skin perfusion from the big toe. Blood flow through the femoral artery was determined with ultrasound. Afterdrop in the test group was smaller than in the control group (1.2+/-0.2 degrees C vs 1.8+/-0.7 degrees C: P=0.04) whilst no significant difference in mean tissue thigh temperature was found between the groups. Local skin temperature was 2.5-3.0 degrees C higher when using forced-air heaters. However, skin perfusion was unaffected. Ultrasound measurements revealed that leg blood flow during the first hours after surgery was reduced to approximately 70% of pre- and peri-operative values. Forced-air blankets reduce afterdrop. However, they do not lead to clinical relevant changes in deep thigh temperature. LDF measurements show that forced-air heating does not improve toe perfusion. The extra heat especially favours core temperature. This is underlined by the decrease in postoperative leg blood flow, suggesting that the majority of the warmed blood leaving the heart flows to core organs and not to the periphery.

Influence of hepatic arterial blockage on blood perfusion and VEGF, MMP-1 expression of implanted liver cancer in rats.

To investigate the influence of hepatic arterial blockage on blood perfusion of transplanted cancer in rat liver and the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-1 (MMP-1), and to explore the mechanisms involved in transarterial embolization (TAE)-induced metastasis of liver cancer preliminarily. Walker 256 carcinosarcoma was transplanted into rat liver to establish the liver cancer model. Hepatic arterial ligation (HAL) was used to block the hepatic arterial blood supply and simulate TAE. Blood perfusion of tumor in control, laparotomy control, and HAL group was analyzed by Hoechst 33342 labeling assay, the serum VEGF level was assayed by ELISA, the expression of VEGF and MMP-1 mRNA was detected by in situ hybridization. Two days after HAL, the number of Hoechst 33342 labeled cells which represent the blood perfusion of tumor directly and hypoxia of tumor indirectly in HAL group decreased significantly compared with that in control group (329+/-29 vs 384+/-19, P<0.01). The serum VEGF level in the HAL group increased significantly as against that of the control group (93 ng.L(-1)+/-44 ng.L(-1) vs 55 ng.L(-1)+/-19 ng.L(-1), P<0.05). The expression of VEGF and MMP-1 mRNA in the tumor tissue of the HAL group increased significantly compared with that of the control and the laparotomy control groups (P<0.05). The blood perfusion data of the tumor, represented by the number of Hoechst 33342 labeled cells, showed a good linear inverse correlation with the serum VEGF level (r=-0.606, P<0.05) and the expression of VEGF mRNA in the tumor tissue ( r =-0.338, P<0.01). Blockage of hepatic arterial blood supply results in decreased blood perfusion and increased expression of metastasis-associated genes VEGF and MMP-1 of transplanted liver cancer in rats. Decreased blood perfusion and hypoxia may be the major cause of up-regulated expression of VEGF.

Application of a lumped-parameter heat exchange model to cold-induced temperature and blood flow measurements in the finger-tip

Measured cold induced vasodilatation (CIVD) temperature and pulse volume changes were used to validate a lumped-parameter heat exchange model of the finger-tip. The simultaneously measured data were extracted from a previous study by Blaisdell (1951). Finger-tip temperatures were estimated using adjusted blood perfusion data as an input. The model was also applied to the inverse problem, namely, to estimate blood perfusion from measured temperatures. A three-segment arterial blood supply temperature profile, composed of an exponential drop followed by a levelling-off and succeeded by an exponential rise, was assumed in order to improve the predictions of the model. Comparison of temperature records showed good conformity, with the estimated values generally under predicting the measured ones. The quality of the predictions of the inverse problem was not as good with local values amounting to less than half the measured ones. In particular the model was shown to retain the basic features of the thermal responses of the cold-stressed extremity, i.e. shape of the curves and the delayed rise of temperature in relation to blood perfusion.

Pulsatile Blood Flow Indices in Lower Extremity Arterial Disease: Leg Only Compared with Leg and Cardiac Parameters

The relative diagnostic value of pulsatile leg blood flow and indices with and without normalization to cardiac stroke volume was determined in 100 subjects (200 legs) with and without lower extremity arterial disease (LEAD) who were stratified on the basis of ankle-brachial pressure index (ABI). Leg blood flow parameters (magnetic resonance flowmetry) included absolute pulsatile flow (Q, mL/min), leg flow per stroke (LSV, mL), and an arterial status index (ASI, mL/min/100 cc). Cardiac stroke volume (CSV) was determined by transthoracic bioimpedance cardiography and was used to obtain the normalized leg/cardiac parameter LSV/CSV. Results show that all tested parameters provide significant statistical separation between LEAD and normal limbs (P &lt; 0.001) but that normalization by CSV was least good and offers no benefit as compared with the leg parameters. Further, based on analysis of receiver operator curves, the ASI parameter, which is derived from leg blood perfusion data, provides the best sensitivity (93.7%-98.1%) and specificity (81.8%-77.7%) of all parameters tested.

Obtaining local SAR and blood perfusion data from temperature measurements: steady state and transient techniques compared

A series of analyses and experiments was performed to determine the extent that SAR and blood perfusion information can be extracted from steady state temperature values and from transient temperature measurements following a step change in applied power. Multiple local temperature measurements were made in canine thighs heated by 2450 MHZ microwaves to evaluate two parameters: the local absorbed power in the tissue, and the local “effective blood perfusion.” The theoretical bases for these calculations are presented in order to identify their underlying assumptions and to obtain a unified basis for comparison of the various calculation methods used by previous investigators. From energy balance considerations it can be shown that the local absorbed power can be obtained from either the rate of increase of temperature immediately following a step increase in power, or from the rate of decrease in temperature immediately following a step decrease in power. These theoretical observations are verified experimentally by comparing the SAR results at fixed positions in canine thighs as calculated from both increasing and decreasing power steps. For decreasing power steps, the resulting decreasing temperature curves can also be used to calculate an effective blood perfusion rate if thermal conduction is included. Alternatively, this same effective blood perfusion rate can be calculated from steady state data. (These two approaches have been used by previous investigators to determine “blood perfusion” values. We have added the modifier “effective” to specifically denote the presence of thermal conduction effects in such perfusion calculations.) From our experimental results and theoretical calculations it appears that differences between the predictions of the two calculation methods arise from changing thermal conduction values during the cooling period of the thermal clearance method. The steady state calculation approach is easier to apply than the washout method, but it requires the additional knowledge of the local SAR value. It is important to realize that effective blood perfusion values calculated using thermal techniques are subject to large errors under conditions where thermal conduction is important, unless this conduction is explicitly included in the calculation. Such effective blood perfusion values should not be quantitatively compared to values calculated from non-thermal techniques that are not affected by thermal conduction. Unless such conduction effects are known to be negligible, effective perfusion values are only qualitative indicators of the presence of changes in blood perfusion.