Tissue Blood Volume Research Articles

An EEMD-PCA approach to extract heart rate, respiratory rate and respiratory activity from PPG signal.

The pulse oximeter's photoplethysmographic (PPG) signals, measure the local variations of blood volume in tissues, reflecting the peripheral pulse modulated by cardiac activity, respiration and other physiological effects. Therefore, PPG can be used to extract the vital cardiorespiratory signals like heart rate (HR), respiratory rate (RR) and respiratory activity (RA) and this will reduce the number of sensors connected to the patient's body for recording vital signs. In this paper, we propose an algorithm based on ensemble empirical mode decomposition with principal component analysis (EEMD-PCA) as a novel approach to estimate HR, RR and RA simultaneously from PPG signal. To examine the performance of the proposed algorithm, we used 45 epochs of PPG, electrocardiogram (ECG) and respiratory signal extracted from the MIMIC database (Physionet ATM data bank). The ECG and capnograph based respiratory signal were used as the ground truth and several metrics such as magnitude squared coherence (MSC), correlation coefficients (CC) and root mean square (RMS) error were used to compare the performance of EEMD-PCA algorithm with most of the existing methods in the literature. Results of EEMD-PCA based extraction of HR, RR and RA from PPG signal showed that the median RMS error (quartiles) obtained for RR was 0 (0, 0.89) breaths/min, for HR was 0.62 (0.56, 0.66) beats/min and for RA the average value of MSC and CC was 0.95 and 0.89 respectively. These results illustrated that the proposed EEMD-PCA approach is more accurate in estimating HR, RR and RA than other existing methods.

Myocardial effective transverse relaxation time T2* Correlates with left ventricular wall thickness: A 7.0 T MRI study

Myocardial effective relaxation time T2* is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influence T2*. To this end, this study investigates the relationship between T2* and cardiac macromorphology given by left ventricular (LV) wall thickness and left ventricular radius, and provides interpretation of the results in the physiological context. High spatio-temporally resolved myocardial CINE T2* mapping was performed in 10 healthy volunteers using a 7.0 Tesla (T) full-body MRI system. Ventricular septal wall thickness, left ventricular inner radius, and T2* were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase-resolved magnetic field maps. Ventricular septal T2* changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness and T2* showed a significant positive correlation, whereas the inner LV radius and T2* were negatively correlated. The effect of macroscopic magnetic field gradients on T2* can be considered minor in the ventricular septum. Our findings suggest that myocardial T2* is related to tissue blood volume fraction. Temporally resolved T2* mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo. Magn Reson Med 77:2381-2389, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

FINGER PLETHYSMOGRAPH TO MONITOR HEART RATE

Heart rate is very important physiological parameter that is directly concerned with the soundness of human cardiovascular system. The condition of the cardiovascular system is examined by haemodynamic measurements and by recording the electrical activity of the heart and heart sound. To estimate the performance of the heart as a pump, measurement of cardiac output, blood pressure, blood volume are important and it is carried out in various ways throughout the circulatory system. This paper describes the noninvasive technique to measure the variation in the blood volume in tissue using a pulse sensor which contains a light source and a detector. As the change in blood volume is related to simultaneous occurrence the heart beat, this method can be used to calculate the heart rate.

Comparison of NIRS, laser Doppler flowmetry, photoplethysmography, and pulse oximetry during vascular occlusion challenges

Monitoring changes in blood volume, blood flow, and oxygenation in tissues is of vital importance in fields such as reconstructive surgery and trauma medicine. Near infrared spectroscopy (NIRS), laser Doppler (LDF) flowmetry, photoplethysmography (PPG), and pulse oximetry (PO) contribute to such fields due to their safe and noninvasive nature. However, the techniques have been rarely investigated simultaneously or altogether. The aim of this study was to investigate all the techniques simultaneously on healthy subjects during vascular occlusion challenges. Sensors were attached on the forearm (NIRS and LDF) and fingers (PPG and PO) of 19 healthy volunteers. Different degrees of vascular occlusion were induced by inflating a pressure cuff on the upper arm. The responses of tissue oxygenation index (NIRS), tissue haemoglobin index (NIRS), flux (LDF), perfusion index (PPG), and arterial oxygen saturation (PO) have been recorded and analyzed. Moreover, the optical densities were calculated from slow varying dc PPG, in order to distinguish changes in venous blood volumes. The indexes showed significant changes (p < 0.05) in almost all occlusions, either venous or over-systolic occlusions. However, differentiation between venous and arterial occlusion by LDF may be challenging and the perfusion index (PI) may not be adequate to indicate venous occlusions. Optical densities may be an additional tool to detect venous occlusions by PPG.

Bayesian analyses demonstrate tissue blood volume is not decreased during acute sickle cell pain episodes: A preliminary study.

Pain is the most common complication of Sickle Cell Disease (SCD). Tissue oximetry properties in SCD during steady state and acute pain are not well described. This was a cross sectional study of tissue oximetry properties in individuals with SCD during steady state, acute pain and healthy controls without SCD. A novel tissue oximetry device was used to better account for tissue pigmentation interference. We hypothesized that during acute SCD pain, blood volume to painful areas would be at least 10% less than steady state. Bayesian analyses of the data (with flat piors) were planned a priori because of the small projected sample size. The sample included 14 individuals (4 during crisis, 5 steady state, and 5 controls). In individuals with SCD, blood volume to the lower back was higher during crisis (0.18% of tissue volume vs. 0.14% ). Bayesian analyses yielded a 3% probability that our hypothesis (that blood volume would decrease by 10% ) was correct. During acute SCD pain, blood volume to painful areas is not decreased. Bayesian analyses were useful for interpretation of small sample data and may have utility in early phase trials for rare diseases.

Do Two Tissue Blood Volume Parameters Measured by Different Near-Infrared Spectroscopy Methods Show the Same Dynamics During Incremental Running?

Both the change in total hemoglobin concentration (cHb), assessed by near-infrared continuous-wave spectroscopy (NIR-CWS), and the normalized tissue hemoglobin index (nTHI), assessed by NIR spatially resolved spectroscopy (NIR-SRS), were used to quantify changes in tissue blood volume. However, it is possible that these parameters may show different changes because of the different measurement systems. The present study aimed to compare changes in cHb and nTHI in working muscles, which were selected for measurement because the parameters changed dynamically. After a standing rest, seven male runners (age 24±3 years, mean±S.D.) performed an incremental running exercise test on a treadmill (inclination=1%) from 180 to 300 m min(-1). During the tests, cHb and nTHI were monitored from the vastus lateralis (VL) and medial gastrocnemius (GM) muscles. These parameters were relatively evaluated from the minimal to maximal values through the test. When the exercise began, cHb and nTHI quickly decreased and then gradually increased during running. In comparison with both VL and GM, there was significant interaction between cHb and nTHI. The present results suggest that cHb and nTHI in working muscles are not always synchronized, particularly at the onset of exercise and at high intensities. Although cHb was previously used as the change of tissue blood volume, it is implied that tissue blood volume assessed by cHb is overestimated.

Intraobserver and Interobserver Agreement in the Evaluation of Tumor Vascularization With Computed Tomography Perfusion in Cirrhotic Patients With Hepatocellular Carcinoma.

To evaluate intrareader and inter-reader agreement in CT perfusion (Perf) measurements in cirrhotic patients with hepatocellular carcinoma (HCC) lesions. Sixteen patients with HCC (9 untreated, 5 recurrence/residual disease after transarterial chemoembolization, and 2 after radiofrequency ablation treatment) underwent standard CT examination and a Perf study; a quantitative map of arterial and portal Perf by means of a color scale was generated. With dedicated Perf software, the following parameters were calculated on untreated and treated HCC lesions and on cirrhotic parenchyma: hepatic Perf, tissue blood volume, hepatic perfusion index, arterial perfusion, and time to peak. Intraobserver and interobserver agreements were assessed for 2 readers with Bland-Altman plots, intraclass correlation coefficients (ICCs), coefficients of variation, and repeatability. In HCC lesions, agreement analysis demonstrated higher intra-agreement values in comparison with interagreement (range of ICC values, 0.26-0.59 between readers and 0.67-0.94 between readings). Lower interagreement was found for treated HCC lesions in comparison with untreated lesions (range of ICC values, respectively, 0.12-0.54 and 0.31-0.89). For all Perf parameters intra-agreement was higher than interagreement, even though a relatively wide range of 95% limits of agreement was found in both cases.

An innovative peak detection algorithm for photoplethysmography signals: an adaptive segmentation method

The purpose of this paper is twofold. The first purpose is to detect M-peaks from raw photoplethysmography (PPG) signals with no preprocessing method applied to the signals. The second purpose is to estimate heart rate variability (HRV) by finding the peaks in the PPG signal. HRV is a measure of the fluctuation of the time interval between heartbeats and is calculated based on time series between strokes derived from electrocardiogram (ECG), arterial pressure (AP), or PPG signals, separately. PPG is a method widely used to measure blood volume of tissue on the basis of blood volume change in every heartbeat. In the estimation of the HRV signal from the PPG signal, HRV is calculated by measuring the time intervals between the peak values in the PPG signal. In the present paper, a novel peak detection algorithm was developed for PPG signals. Finding peak values correctly from PPG signals, the HRV signal can be estimated. This peak detection algorithm has been called an adaptive segmentation method (ASM). In this method, the PPG signals are first separated into segments with sample sizes and then the peak points in these signals are detected by comparing with maximum points in these segments. To evaluate the estimated pulse rate and HRV signals from PPG, Poincar\'{e} plots and time domain features including minimum, maximum, mean, mode, standard deviation, variance, skewness, and kurtosis values were used. Our experimental results demonstrated that ASM could be even used both in the estimation of HRV signals and to detect the peaks from raw and noisy PPG signals without a pre-processing method.

Determination of the Input Function at the Entry of the Tissue of Interest and Its Impact on PET Kinetic Modeling Parameters.

Quantitative positron emission tomography (PET) imaging is employed with several measurement protocols all relying on the a priori determination of the input function (IF). The standard technique to determine IF is by blood sampling. However, a unique IF determined in a subject for a given PET study, either defined by sampling or in the images, and commonly utilized for all analyzed tissues in that study equally at rest and during interventions, is expected to provoke biases in the rate constants and in tissue blood volume. The determination of a specific IF at the site of the tissue to be analyzed enhances PET accuracy and renders PET imaging less invasive.

Value or waste: Perfusion imaging following radiofrequency ablation - early experience.

Radiofrequency ablation (RFA) is an evolving technique in treatment of hepatic malignant tumors. By heating local tissue it leads to coagulative necrotic areas around the ablation probe. Temperature falls with increasing distance to the probe, risking incomplete necrosis at the margins of the RFA-induced lesion. Therefore, immediate non-invasive and precise detection of incomplete ablation is necessary for early enlargement of the ablation if needed. This in vivo pig study compares early experiences of immediate post-interventional computed tomography (CT) perfusion volume analysis to macroscopic and CT image evaluation in healthy pig liver. RFA was performed in vivo in healthy pig livers. Different CT perfusion algorithms (Maximum slope analysis and Patlak plot) were used to quantify three different perfusion parameters. Data points were acquired from rectangular grids. These grids were semiautomatically overlayed to macroscopic images documented after liver explantation. Each data point was visually assigned to zones defined as "inner" and "outer necrotic zone", "margin" or "vital tissue". Significant differences between necrotic zones and vital tissue are shown for equivalent blood volume (p < 0.0001), arterial flow (p < 0.01) and flow extraction product (p < 0.001). Looking at equivalent blood volume and flow extraction product, there were also significant differences (EquivBV: p < 0.0001, FE: p < 0.001) between margins, necrotic and vital areas. In a porcine model these early results could show that all of the used CT perfusion parameters allowed discrimination of necrosis from vital tissue after RFA at high levels of significance. In addition, the parameters EquivBV and FE that give an estimate of the tissue blood volume and the permeability, were able to precisely discern different zones also seen macroscopically. From this data CT perfusion analysis could be precise tool for measurement and visualization of ablated liver lesions and for immediate detection of incomplete ablation areas.

Estimating instantaneous respiratory rate from the photoplethysmogram.

The photoplethysmogram (PPG) obtained from pulse oximetry shows the local changes of blood volume in tissues. Respiration induces variation in the PPG baseline due to the variation in venous blood return during each breathing cycle. We have proposed an algorithm based on the synchrosqueezing transform (SST) to estimate instantaneous respiratory rate (IRR) from the PPG. The SST is a combination of wavelet analysis and a reallocation method which aims to sharpen the time-frequency representation of the signal and can provide an accurate estimation of instantaneous frequency. In this application, the SST was applied to the PPG and IRR was detected as the predominant ridge in the respiratory band (0.1 Hz - 1 Hz) in the SST plane. The algorithm was tested against the Capnobase benchmark dataset that contains PPG, capnography, and expert labelled reference respiratory rate from 42 subjects. The IRR estimation accuracy was assessed using the root mean square (RMS) error and Bland-Altman plot. The median RMS error was 0.39 breaths/min for all subjects which ranged from the lowest error of 0.18 breaths/min to the highest error of 13.86 breaths/min. A Bland-Altman plot showed an agreement between the IRR obtained from PPG and reference respiratory rate with a bias of -0.32 and limits agreement of -7.72 to 7.07. Extracting IRR from PPG expands the functionality of pulse oximeters and provides additional diagnostic power to this non-invasive monitoring tool.

Predictive Modeling of Drug Response in Non-Hodgkin's Lymphoma.

We combine mathematical modeling with experiments in living mice to quantify the relative roles of intrinsic cellular vs. tissue-scale physiological contributors to chemotherapy drug resistance, which are difficult to understand solely through experimentation. Experiments in cell culture and in mice with drug-sensitive (Eµ-myc/Arf-/-) and drug-resistant (Eµ-myc/p53-/-) lymphoma cell lines were conducted to calibrate and validate a mechanistic mathematical model. Inputs to inform the model include tumor drug transport characteristics, such as blood volume fraction, average geometric mean blood vessel radius, drug diffusion penetration distance, and drug response in cell culture. Model results show that the drug response in mice, represented by the fraction of dead tumor volume, can be reliably predicted from these inputs. Hence, a proof-of-principle for predictive quantification of lymphoma drug therapy was established based on both cellular and tissue-scale physiological contributions. We further demonstrate that, if the in vitro cytotoxic response of a specific cancer cell line under chemotherapy is known, the model is then able to predict the treatment efficacy in vivo. Lastly, tissue blood volume fraction was determined to be the most sensitive model parameter and a primary contributor to drug resistance.

Two Tissue Blood Volume Parameters Show Different Dynamics During Prolonged Exercise

In previous studies, total hemoglobin changes (cHb), which were calculated by adding the oxygenated and deoxygenated hemoglobin, measured by near-infrared continuous-wave spectroscopy (NIR-CWS), are used as tissue blood volume changes (BV). During moderate to high intensity cycling exercise, cHb decreases temporarily at the onset of exercise, and then increases gradually. However, since NIR-CWS parameters, especially oxygenated hemoglobin, are affected by skin blood flow changes, it was hypothesized that BV assessed by cHb was overestimated, especially during prolonged exercise. On the other hand, it was reported that tissue oxygen saturation and a normalized tissue hemoglobin index (nTHI), monitored by NIR spatially-resolved spectroscopy (NIR-SRS), were less influenced. PURPOSE:The aim of this study was to compare the two BV parameters, cHb and nTHI, in the working muscle during prolonged cycling exercise. METHODS :Seven active male subjects (age, 22 ± 3 yr.) performed a 60-min cycling exercise test at 65 to 70% of the peak of pulmonary oxygen uptake (162 ± 25 W). Two BV parameters, cHb and nTHI, from the vastus lateralis muscle were continuously monitored by the commercially available NIR device. The values of the two parameters were relatively evaluated; 100% of BV was taken as the resting value and 0% of BV was taken as the minimum value for 30 s after the onset of exercise. All data are represented as mean ± SE. RESULTS::Both cHb and nTHI decreased acutely at the onset of exercise, and then increased. The relative values of cHb at the 10th, 30th, and 60th minutes were 230 ± 70%, 277 ± 74%, and 291 ± 56%, respectively. On the other hand, those of nTHI were 173 ± 37%, 177 ± 39%, and 170 ± 45%, respectively. There was significant interaction between the two parameters (p < 0.01). The maximal values in cHb and nTHI were 321 ± 76% and 235 ± 36% (N.S.), and the timing at the maximal value in cHb was significantly increased compared to nTHI (53.4 ± 5.1 min vs. 22.5 ± 19.6 min, p < 0.01). CONCLUSION: These results suggest that BV assessed by cHb during exercise is overestimated. Hence, it is likely that BV within the working muscle might be little changed or slightly decreased during prolonged exercise.

Noninvasive assessment of ischemic penumbra by using MR-SWI during the acute phase of cerebral infarction: a comparison to PWI

Background: Assessment of ischemic penumbra during the acute stage of cerebral infarction is crucial for a decision to initiate thrombolytic therapy and for predicting stroke evolution. Although controversial as a perfect equivalence to penumbra, perfusion weighted imaging (PWI)-diffusion weighted imaging (DWI) mismatch may predict the response to thrombolysis. Due to the reliance on contrast agents in PWI, noninvasive alternatives remain an unmet need. Methods: We herein investigate the potentials of SWI as an alternative to PWI in defining ischemic penumbra and in predicting stroke outcome. A multimodal magnetic resonance imaging work-up which includes conventional magnetic resonance imaging sequences (T1WI, T2WI and FLAIR), DWI, PWI and SWI was performed. The Alberta Stroke Programme Early CT Score (ASPECTS) was used to evaluate the changes in DWI, SWI and PWI. Results: The mismatch of SWI-DWI was comparable with that of PWI-DWI (p&gt;0.05). Furthermore, the grade of prominent vein and the cerebral blood volume in the ipsilateral brain tissue were positively correlated. Conclusions: SWI can be used as a noninvasive alternative to identify occlusive arteries and to evaluate the ischemic penumbra. The susceptibility vein sign may represent thrombosis in arteries whereby being helpful to identify responsible blood vessels in ischemic stroke.

Individual variability analysis of fluorescence parameters measured in skin with different levels of nutritive blood flow

Fluorescence spectroscopy has recently become more common in clinical medicine. However, there are still many unresolved issues related to the methodology and implementation of instruments with this technology.In this study, we aimed to assess individual variability of fluorescence parameters of endogenous markers (NADH, FAD, etc.) measured by fluorescent spectroscopy (FS) in situ and to analyse the factors that lead to a significant scatter of results. Most studied fluorophores have an acceptable scatter of values (mostly up to 30%) for diagnostic purposes. Here we provide evidence that the level of blood volume in tissue impacts FS data with a significant inverse correlation. The distribution function of the fluorescence intensity and the fluorescent contrast coefficient values are a function of the normal distribution for most of the studied fluorophores and the redox ratio. The effects of various physiological (different content of skin melanin) and technical (characteristics of optical filters) factors on the measurement results were additionally studied.The data on the variability of the measurement results in FS should be considered when interpreting the diagnostic parameters, as well as when developing new algorithms for data processing and FS devices.

Adaptation of local muscle blood flow and surface electromyography to repeated bouts of eccentric exercise.

The aim of this randomized controlled crossover study was to investigate the effect of a bout of unaccustomed eccentric exercise (ECC) followed by a consecutive bout of the same intensity on local muscle blood flow, amplitude, and frequency of the electromyographic (EMG) signal from the exercised tibialis anterior muscle. Sixteen healthy male participants (age, 25.7 (0.6) years; body mass index 24.8 (1) kg·m(-2) participated in this study. Two identical bouts of high-intensity ECC were performed on the tibialis anterior muscle 7 days apart. Control sessions involving no exercise were performed 4 weeks either before or after the exercise sessions. Changes in local total blood flow [ΔtHb], EMG root mean square, and median power frequency were recorded during isometric maximum voluntary contraction of ankle dorsiflexion. Measurements were performed before, immediately after, and the day after both ECCs (ECC1 and ECC2). The participants rested quietly in a chair in the control session. Eccentric exercise 1 led to a significant decrease in [ΔtHb] on the day after (p ≤ 0.05), whereas ECC2 did not. Median power frequency decreased significantly in ECC2 compared with ECC1 (p < 0.01). Root mean square was unchanged in all the instants. The present study showed that adaptation is depicted in the local muscle blood flow and the frequency contents of the EMG after an unaccustomed ECC inducing muscle soreness. These alterations provide a potential mechanism for a rapid adaptation, which decreases susceptibility of the muscle to develop further soreness in the subsequent ECC bout.

Abstract W P393: Postural-related Cerebral Hemodynamic Responses Assessed by Near Infrared Spectroscopy in Patients with Chronic Cerebral Infarction

Introduction: Near infrared spectroscopy (NIRS) is a non-invasive optical technique to monitor dynamic cerebral tissue blood volume. Although previous studies have implied cerebral blood volume changed slightly during acute orthostatic stress, the impact of chronic cerebral infarction (CI) on the cerebral hemodynamic response during postural change was unclear. Hypothesis: We hypothesized that chronic CI was independently associated with decreasing cerebral blood flow (CBF) during active orthostatic stress. Methods: We designed a cross sectional study to investigate the relation between chronic CI and the postural-related changes of CBF. A total of 100 subjects with or without chronic CI were enrolled in this study. Postural-related changes of average bilateral frontal cortical CBF were non-invasively and continuously measured by using NIRS (NIRO 100, Hamamatsu Photonics, Shizuoka, Japan) during orthostatic stress. Results: The proportion of decreasing CBF during active orthostatic stress was higher in patients with chronic CI than in those without chronic CI (76.3% and 30.6%, respectively, p&lt;0.001). The changes in CBF during active orthostatic stress in patients with chronic CI were significantly lower than those in participants without chronic CI (-4.5±7.4% and 1.7±4.1%, respectively, p&lt;0.001) In unadjusted model, the odds ratio (OR) (95% confidence interval) for decreasing CBF during active orthostatic stress in patients with chronic CI was 3.22 (1.52-6.81, p=0.002). After adjusted covariates, a multiple logistic-regression analysis revealed that the adjusted OR (95%CI) was 5.23 (1.68-16.32, p=0.004). Conclusion: Chronic CI was an independent risk factor for decreasing CBF during active orthostatic stress.

Blood volume and oxygenation monitoring in muscle and brown adipose tissue using near-infrared

Blood volume and oxygenation monitoring in muscle and brown adipose tissue using near-infrared

Inexpensive diffuse reflectance spectroscopy system for measuring changes in tissue optical properties.

The measurement of changes in blood volume in tissue is important for monitoring the effects of a wide range of therapeutic interventions, from radiation therapy to skin-flap transplants. Many systems available for purchase are either expensive or difficult to use, limiting their utility in the clinical setting. A low-cost system, capable of measuring changes in tissue blood volume via diffuse reflectance spectroscopy is presented. The system consists of an integrating sphere coupled via optical fibers to a broadband light source and a spectrometer. Validation data are presented to illustrate the accuracy and reproducibility of the system. The validity and utility of this in vivo system were demonstrated in a skin blanching/reddening experiment using epinephrine and lidocaine, and in a study measuring the severity of radiation-induced erythema during radiation therapy.

853P - Prediction of Response of Primary Tumors to Neoadjuvant Sunitinib Using Perfusion (Dce) Computed Tomography (Ct) in Metastatic Renal Cell Carcinoma (Mrcc) Patients (Preinsut Trial)

ABSTRACT Aim: Sunitinib is approved in 1st line for mRCC patients, but the prognosis remains poor with a median PFS of 11 months and an overall survival of 2-3 years. Determination of predictive biomarkers of response to sunitinib is urgently needed. The PREINSUT trial was conducted to determine biological, pathological and imaging markers for a neoadjuvant sunitinib in mRCC patients prior to nephrectomy. The perfusion imaging sub-analysis is presented here. Methods: Thirty-three patients were included to assess the efficacy of 2 cycles of neoadjuvant sunitinib (50mg, 4weeks/6) before nephrectomy. DCE scans were performed at baseline and at the end of the 4 weeks of the 1st cycle of sunitinib. The following perfusion parameters were calculated in the primary renal tumor and correlated to the response in size at the end of the neoadjuvant therapy: tissue blood flow (Ft), tissue blood volume (Vt), permeability surface coefficient (PS), area under the enhancement curve at 60s (AUC). Patients were considered responders if there was a decrease ≥ 10 % of the renal tumor size. Perfusion parameters were compared between responders and non-responders using a Mann-Whitney test and correlated to changes in size using the Spearman correlation (r). Results: Nineteen patients were eligible for the DCE imaging analysis. Mean baseline values of Ft, Vt, PS and AUC were 212 ± 136 mL/min/100mL, 29 ± 13%, 8.3 ± 4.2 mL/min/100mL, and 0.4 ± 0.2, respectively. There was a negative correlation between baseline values of Ft and the response in size (r = -0.54, p = 0.04), PS (r = -0.53, p = 0.04). Responders (N = 7) had a larger decrease in AUC between baseline and 4 weeks than non-responders (N = 12) (-39.2% vs 6.0%, p = 0.04). There was a positive correlation between size response and both PS (r = 0.62, p = 0.02), and AUC changes (r = 0.65, p = 0.02). Blood volume was negatively correlated, moderately but significantly, to plasmatic VEGF levels (r = -0.36, p = 0.01). Conclusions: Perfusion CT parameters measured on baseline and early changes (4 weeks) after neoadjuvant sunitinib therapy were predictive of the final 3-months response of the renal tumor. We demonstrate in this study that the higher the tumor perfusion and permeability, the greater the reduction in size of the primary renal tumor. Disclosure: Y. Vano: Honoraria from: Pfizer, Novartis, GSK, Sanofi, Astellas, Sandoz, Teva; S. Oudard: Consultant or Advisory Role: Sanofi, Novartis, Roche, Bayer, Keocyt, Amgen, Honoraria: Sanofi, Novartis, Roche, Bayer, Keocyt, Amgen, Pfizer. All other authors have declared no conflicts of interest.