Differences In Blood Volume Research Articles

Comparison of Blood Volume Profiles in Heart Failure With Preserved and Reduced Ejection Fractions: Sex Makes a Difference.

Blood volume (BV) profiles vary markedly in patients with heart failure (HF), but how HF phenotypes and patient sex impact volume profiles remain to be explored. The aim of the study was to differentiate BV, plasma volume, and red blood cell mass profiles by phenotypes of preserved and reduced left ventricular ejection fractions and assess the impact of patient sex on profile heterogeneity. Retrospective analysis of clinical and BV data was undertaken in patients with chronic New York Heart Association II-III heart failure. BV was quantitated using the nuclear medicine indicator-dilution methodology. A total of 530 BV analyses (360 HF with reduced ejection fraction and 170 HF with preserved ejection fraction) were identified in 395 unique patients. Absolute BV was greater in HF with reduced ejection fraction (6.7±1.8 versus 5.9±1.6 liters: P<0.001); however, large variability in frequency distribution of volume profiles was observed in both phenotypes (-22% deficit to +109% excess relative to normal volumes). HF with reduced ejection fraction was characterized by a higher prevalence of BV expansion ≥+25% of normal (39% versus 26%; P=0.003), and HF with preserved ejection fraction was characterized a by more frequent normal BV (42% versus 24%; P<0.001). Male sex in both phenotypes was associated with a larger absolute BV (7.0±1.6 versus 5.1±1.3 liters; P<0.001) and higher frequency of large BV and plasma volume expansions above normal (both P<0.001), while females in both phenotypes demonstrated a higher prevalence of normal BV and plasma volume (both P<0.001). Findings support significant differences in BV, plasma volume, and red blood cell mass profile distributions between heart failure phenotypes, driven in large part by sex-specific factors. This underscores the importance of identifying and distinguishing individual patient volume profiles to help guide volume management strategies.

Perfusion Computed Tomography in Rectal Carcinoma: Influence of Optimization of the Patlak Range on Calculation of Equivalent Blood Volume and Flow Extraction.

The aim of the study is to assess the influence of manual adjustment of the Patlak range in computed tomography (CT) perfusion analysis of rectal carcinoma compared with default range of the perfusion software. This study was approved by the institutional review board and informed consent was obtained. Twenty-one patients (12 male, 9 female; mean age ± SD, 59 ± 11 years) with rectal cancer were included and underwent perfusion CT before preoperative chemoradiotherapy. Equivalent blood volume (BV) and flow-extraction (FE) were calculated using the Patlak plot model. Two perfusion sets were calculated per patient, a perfusion set using the default setting as provided by the software (dBV, dFE) and an optimized perfusion set after manual adaption of the Patlak range (aBV, aFE), which was limited to the intravascular space clearance of contrast to the extravascular space. Perfusion values calculated with both methods were compared for significance in differences using the Wilcoxon test. A P value of 0.05 or less was defined as statistically significant. Adjustment of the Patlak range statistically significantly influenced BV and FE calculation. Median dBV was 23.2 mL/100 mL (interquartile range [IQR], 12.1 mL/100 mL), whereas median aBV was 20.3 mL/100 mL (IQR, 10.9 mL/100 mL). The difference in BV was statistically significant ( P = 0.021). Median dFE was 8.3 mL/min/100 mL (IQR, 4.7 mL/min/100 mL), whereas median aFE was 15.4 mL/min/100 mL (IQR, 5.8 mL/min/100 mL). The difference in FE was statistically significant ( P < 0.001). Our findings indicate that in perfusion CT of rectal carcinoma, adjustment of the Patlak range may significantly influence BV and FE compared with default setting of the software. This may contribute to standardization in the use of this technique for functional imaging of rectal cancer.

Non-invasive evaluation of esophageal varices in patients with liver cirrhosis using low-dose splenic perfusion CT

PurposeTo assess the value of splenic hemodynamic parameters measured using low-dose perfusion CT in the noninvasive evaluation of esophageal varices (EV) in patients with liver cirrhosis. MethodsWe retrospectively studied 43 cirrhotic patients with EV, which were divided into mild (EV1), moderate (EV2) and severe (EV3) groups. 14 patients with normal liver function and no EV were selected as the control group. All patients underwent low-dose splenic perfusion CT and radiation dose were recorded. Spleen perfusion parameters, including blood volume (BV), blood flow (BF) and permeability surface (PS), were obtained. The volume of the spleen (V-S) was measured. The total blood volume of the spleen (BV-S) was obtained using the product of V-S and BV. The measurement differences among the four groups were analyzed using ANOVA with Welch correction. Least Significant Difference (LSD) was used for the multiple comparison. P < 0.05 was considered statistically significant. ResultsThere were statistically significant differences in BV, BF, PS, V-S, and BV-S among different groups (p < 0.05). PS, V-S, and BV-S were higher, and BV and BF were lower in the study groups than those in the control group. There was a statistically significant difference between EV2 and EV1 groups, and EV2 and EV3 groups in BV and BF. The average dose-length product (DLP) was 1286.41 ± 261.15 mGy*cm, and the effective radiation dose（Deff）was 19.30 ± 3.92 mSv. ConclusionThe splenic perfusion parameters obtained in the low-dose splenic perfusion CT could be used to noninvasively evaluate the degrees of EV in cirrhotic patients.

A Pilot Study to Evaluate Early Predictive Value of Thorax Perfusion-CT in Advanced NSCLC.

Simple SummaryThe use of targeted drugs has brought about the development of new imaging techniques which are able to assess in vivo processes and changes in vascularization parameters can be captured as part of the antitumor response to antiangiogenic therapies. This pilot study (IMPACT trial, NCT02316327) aimed to explore the capacity of Perfusion-Computed Tomography (pCT) to detect early changes in tumor vascularization in non-small cell lung cancer (NSCLC) patients treated with an antiangiogenic-based therapy. Our results confirm the feasibility of pCT to capture early changes in tumor vasculature and suggest the potential of blood volume (BV) to early identify differential tumor responses to antiangiogenic therapy.Background: The role of perfusion computed tomography (pCT) in detecting changes in tumor vascularization as part of a response to antiangiogenic therapy in non-small cell lung cancer (NSCLC) remains unclear. Methods: In this prospective pilot study (IMPACT trial, NCT02316327), we aimed to determine the ability of pCT to detect early changes in blood flow (BF), blood volume (BV), and permeability (PMB), and to explore whether these changes could predict the response at day +42 in patients with advanced, treatment-naive, non-squamous NSCLC treated with cisplatin and gemcitabine plus bevacizumab. Results: All of the perfusion parameters showed a consistent decrease during the course of treatment. The BV difference between baseline and early assessment was significant (p = 0.013), whereas all perfusion parameters showed significant differences between baseline and day +42 (p = 0.003, p = 0.049, and p = 0.002, respectively). Among the 16 patients evaluable for efficacy, a significant decline in BV at day +7 from baseline was observed in tumors with no response (p = 0.0418). Conclusions: Our results confirm that pCT can capture early changes in tumor vasculature. A substantial early decline of BV from baseline might identify tumors less likely responsive to antiangiogenic-drugs.

Volume computed tomography perfusion as a predictive marker for treatment response to concurrent chemoradiotherapy in cervical cancer: a prospective study

Computed tomography perfusion (CTP) can provide information on blood perfusion as a reliable marker of tumor response to therapy. To assess the role of volume CTP (vCTP) parameters in predicting treatment response to concurrent chemoradiotherapy (CCRT) for cervical cancer. Thirty-three patients with cervical cancer underwent vCTP. Three CTP parameters of cervical cancer-including arterial flow (AF), blood volume (BV), and permeability surface (PS)-were measured in two different ways: the region of interest incorporating the "local hot" with the highest enhancement and "cold spot" with the lowest enhancement; and "whole-tumor" measurements. The patients were divided into non-residual and residual tumor groups according to the short-term response to treatment. The clinical and perfusion parameters were compared between the two groups. There was no significant difference in age, body mass index, FIGO stage, pathological grade, or pretreatment tumor size between the two groups (P > 0.05). The non-residual tumor group had higher pretreatment AF in high-perfusion and low-perfusion subregions than the residual tumor group (P <0.05), but the AF in whole-tumor regions was not different between the two groups (P > 0.05). There were no differences in BV and PS between the two groups (P > 0.05). The diagnostic potency of AF in the low-perfusion subregion was higher than that in the high-perfusion subregion. vCTP parameters are valuable for the prediction of short-term effects. The AF in the low-perfusion subregion was a more effective index for predicting treatment response to CCRT of cervical cancer.

Survival time after hemorrhage (STaH) in inbred rats with known blood volumes

Eight‐fold differences in STaH were detected among 15 inbred rat strains (Klemcke et al., Shock 29:748, 2008) suggesting genetic effects on STaH. In that study, blood volumes (BV) for all strains were assumed to be 5.83 % of body weight and 55% of that BV was removed. We also showed that differences in STaH might reflect strain‐dependent differences in BV (Klemcke et al., FASEB J 23: 801.1, 2009). To address this hypothesis, each rat of 5 inbred rat strains was hemorrhaged based on its own BV measured using Evans Blue dye 24 hr prior to hemorrhage and its STaH determination. BV varied (P &lt;0.01) among Brown Norway (BN/Mcwi; n = 14; 7.43 ± .10 ml/100 g body weight, mean ± SEM), Salt Sensitive (S; n = 10; 7.08 ± .15), Fawn Hooded Hypertensive (FHH; n=10; 6.74 ± .08), Lewis (LEW; n=10; 6.74 ± .08), and DA (n=10; 6.74 ± .08) rat strains. With equal hemorrhages (47.1 ± .05 % of measured BV), STaH did not differ among rat strains (155 ± 12 min; P = 0.95). When considering both studies it is apparent that: 1) Strain‐related differences in BV contributed to differences in STaH in our 1st study; 2) In FHH rats 1.3% more of total BV was removed in the current study, yet they survived 1.5 hr longer; and 3) In LEW rats identical BV were removed in both studies, yet currently LEW rats survived 1 hr longer. Such observations suggest that Evans Blue dye and/or blood sampling for BV determinations might be preconditioning stimuli that improve STaH in some rat strains.

SU‐FF‐I‐89: A Comparison of Perfusion Parameters From the Kinetic Modeling of Head and Neck Cancers in DCE CT

Purpose: While various kinetic models are used for estimating perfusion parameters from contrast‐enhanced CT scans, the difference amongst the model results are not well researched. The aim of this study was to determine the discrepancy between two of the most commonly used kinetic models: maximum‐slope and deconvolution. Methods: Seven patients with head and neck tumors underwent dynamic CT scans with an injected contrast agent. Contrast enhancement curves were obtained by segmenting arteries, veins, and tumor ROIs from the CT scans. The maximum‐slope model was used to calculate the blood flow, while the Patlak analysis interpolated the blood volume ratio and the permeability. The central volume theorem determined the mean transit time. These parameters were also generated via a deconvolution method implemented in the GE's Advantage Perfusion 4 software. Results: The mean population values of all parameters ‐ blood flow (BF), blood volume (BV), permeability (P) and mean transient time MTT) ‐ were similar between the maximum slope and deconvolution methods (BV: 116 vs 107 ml/100g/min, BV: 6.9 vs 7.9 ml/100g, P: 29 vs 20 ml/100g/min, MTT: 4.9 vs 7.3 s). However, on the individual patient level the difference were significant (BF difference: 70% ±60 %, BV difference: 35% ± 30%, P difference: 75% ± 60%. and MTT difference: 35% ± 25%. Conclusion: No significant differences were found amongst the mean population perfusion parameters. However, on the individual patient level, the differences were significant between the maximum slope and deconvolution‐based CT perfusion methods.

Simultaneous acquisition of CT angiography and whole brain CT perfusion images by using multiphase dynamic helical scan on 16 MDCT

We implemented a new protocol—multiphase dynamic helical scan to acquire CT angiography (CTA) and whole brain CT perfusion (CTP) images simultaneously with single scan on 16 multidetector CT (MDCT). A total of 90 patients who were randomly assigned into 3 groups were included in our study. Each group underwent CT scan by using the new protocol, traditional CTA and CTP protocol, respectively. The image quality of CTA, the CTP parameter values and the X-ray doses were measured and compared between the new protocol and the traditional protocols. There was no statistically significant difference in the CTA image quality between the above methods (P = 0.55). For CTP parameters, the new protocol tended to overestimate the blood volume (BV) and blood flow (BF) value, and to underestimate the mean transit time (MTT) value compared with the traditional method. However, there was no statistically significant difference in BV, BF, and MTT value between the two methods except permeability surface (PS) (P>0.05). The volume CT dose index (CTDIvol) and dose length product (DLP) of our protocol were lower than the traditional one. The new protocol can obtain valuable diagnostic information in a shorter time without significant compromise in image quality. In addition, it reduces the radiation dose as well as contrast medium usage on the patient.

Tumor blood volume assays using contrast-enhanced magnetic resonance imaging: regional heterogeneity and postmortem artifacts.

Tumor blood volume (BV), subject to both morphologic and physiologic influences, can be measured using contrast-enhanced magnetic resonance imaging (MRI). The aims of this study were to determine whether MRI enhanced with a macromolecular contrast medium (MMCM) could resolve differences in BV between different tumor types, between different regions within tumors, and within the same tumor in life and after death. Tumor BV estimates were based on the MRI signal intensity responses in the tumors and in reference venous blood following enhancement with a blood pool MMCM using two mammary adenocarcinoma models. Estimates of BV were made before and immediately following death. An in vitro measurement of tumor gadolinium concentration following death was correlated with MRI enhancement. Statistically significant differences (P < 0.05) were observed in MRI-estimated tumor BV between tumor subtypes, between in vivo and postmortem measurements, and between the tumor periphery and tumor centers. MRI assays enhanced with a macromolecular contrast agent can resolve blood volume differences between tumor types, between regions within the same tumor, and between vital and postmortem states.

Vascular capacitance and reversal of 2-kidney, 1-clip hypertension in rats.

Vascular capacitance was studied in conscious early-phase (less than 6 wk) 2-kidney, 1-clip (2K, 1C) hypertension and compared with sham-clipped control rats. Two other groups of 2K, 1C rats were studied before and 6 h after unclipping or a sham operation. Mean circulatory filling pressure (MCFP) was measured during a brief circulatory arrest caused by inflation of a right atrial balloon. Blood volume (BV) was determined from plasma volume (125I-labeled albumin) and hematocrit. MCFP was measured at resting BV and after rapid BV changes. Vascular compliance was derived from the MCFP-BV curve. Hypertensive 2K, 1C rats had an increase in hematocrit (46 +/- 1.3 vs. 42 +/- 0.4%, P less than 0.01) and no difference in BV compared with controls. MCFP was increased (8.6 +/- 1.0 vs. 7.2 +/- 0.2 mmHg, P less than 0.01) with no difference in compliance, indicating decreased unstressed vascular volume in the 2K, 1C group. After unclipping, there was a significant fall in mean arterial pressure to normal, with a fall in MCFP (8.14 +/- 0.32 to 6.78 +/- 0.11 mmHg, P less than 0.01), but there was no difference in BV or compliance compared with the 2K, 1C group, indicating an increase in unstressed vascular volume after unclipping. These studies for the first time show an important role for vascular capacitance in modulating the circulatory changes accompanying the fall in blood pressure in surgical reversal of 2K, 1C hypertension.

Decreased total venous capacity in Goldblatt hypertensive rats.

Mean circulatory filling pressure (MCFP) and total blood volume (BV) were determined in conscious rats during the early, intermediate, and chronic phases of one-kidney, one-clip Goldblatt hypertension. MCFP was determined from arterial and venous plateau pressures during brief circulatory arrest, which was accomplished by inflating an indwelling right atrial balloon. BV as determined from plasma volume (125I-albumin), arterial hematocrit, and the F-cells factor. As compared with one-kidney sham groups, MCFP was significantly increased in one-kidney, one-clip Goldblatt hypertensive groups at 3, 14, and 28 days postclipping, whereas no significant differences in BV between hypertensive and normotensive groups were observed at any of these time periods. Total vascular compliance, estimated by measuring MCFP before and immediately after rapid BV changes, was significantly decreased in all one-kidney, one-clip Goldblatt hypertensive groups. These results indicate that venous constriction was increased and whole-body venous capacity was decreased in all three phases of one-kidney, one-clip Goldblatt hypertension studied. The mechanism leading to increased venous constriction in one-kidney, one-clip Goldblatt hypertension remains to be elucidated.