Identification of Local Recurrence and Radiofibrosis by Computed Tomography Perfusion on Nasopharyngeal Carcinoma after Radiotherapy

2010 ◽  
Vol 61 (5) ◽  
pp. 265-270 ◽  
Author(s):  
Danke Su ◽  
Guanqiao Jin ◽  
Dong Xie ◽  
Younan Liu
Keyword(s):  
Computed Tomography ◽  
Blood Flow ◽  
Nasopharyngeal Carcinoma ◽  
Local Recurrence ◽  
Microvessel Density ◽  
Mean Transit Time ◽  
Perfusion Ct ◽  
Permeability Surface ◽  
Area Product ◽  
Time Density

Purpose The aim of this study was to investigate the role of perfusion computed tomography (CT) for identification of local recurrence (LR) and radiofibrosis (RF) in patients with nasopharyngeal carcinoma after radiotherapy. Methods Forty-eight prospective patients were recruited for this study. NPC diagnosis was confirmed by pathologic biopsy examination. Immunohistochemistry staining was used on biopsy specimens, and microvessel density was calculated by microscopy. Perfusion CT was performed on both the LR group ( n = 31) and the RF group ( n = 17) after intravenous injection of contrast medium. Time-density curve, blood flow, blood volume, and mean transit time, as well as permeability surface area product, were analyzed as perfusion CT parameters. The microvessel density was compared between both the LR and RF groups. Results There is a significant difference between the LR and RF groups in microvessel density, the time density curve, blood flow blood volume, mean transit time, and the permeability surface area product ( P < .01). Conclusions The results demonstrate that perfusion CT is a reliable and accurate method to identify LR and RF after radiotherapy in patients with nasopharyngeal carcinoma.

scholarly journals Perfusion Computer Tomography Assessment of the Effect of Angiotensin II On Blood Flow Distribution in Rabbits with Intrarenal VX2 Tumors

2018 ◽  
Vol 47 (1) ◽  
pp. 97-106
Author(s):  
Ying-Jin Xu ◽  
Song-Hong Wu ◽  
Huai-Jun Liu ◽  
Pei Niu ◽  
Wen-Zeng Shen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Surface Area ◽  
Renal Cortex ◽  
Perfusion Ct ◽  
Capillary Network ◽  
Arterial Blood ◽  
Permeability Surface ◽  
Group B ◽  
Area Product

Background/Aims: Unlike other organs, which only have one set of capillary network, the renal microvasculature consists of two sets of capillary network series connected by efferent arterioles. Angiotensin II constricts the efferent glomerular artery. Hence, renal tumor blood flow (BF) distribution may be different from tumors in other organs. This study aims to investigate the effects of angiotensin II on the hemodynamics of intrarenal VX2 tumors using perfusion computed tomography(CT). Methods: Twenty-four male New Zealand white rabbits were randomly divided into three groups: groups A (blank controls), group B (negative controls), and group C (angiotensin II-treated animals). Group B and C were established to the model of intrarenal VX2 tumors. Furthermore, perfusion CT of the kidney was performed in each group. Prior to perfusion CT scan in group C, the mean arterial blood was elevated to 150-160 mmHg by angiotensin II. The BF, blood volume (BV), mean transit time (MTT), capillary permeability-surface area product (PS), and relative permeability-surface area product (RPS) of tumors and renal tissues were calculated. Results: Compared with normal renal cortex tissues in group A, the BF, BV and PS values of tumors in group B were significantly lower, MTT was prolonged and RPS increased. Compared with group B, only the RPS of these tumors increased from 83.23 ± 29.17% to 120.94 ± 31.84% by angiotensin II infusion. Angiotensin II significantly increased the RPS value of the renal cortex distant from the tumor (CDT) and the right renal cortex (RRC). Conclusions: Perfusion CT can accurately observe the influence of angiotensin II on normal and tumor BF in kidneys. This clarifies the effect of angiotensin II on intrarenal tumor hemodynamics.

scholarly journals Quantitative Measurement of Cerebral Blood Flow and Cerebral Blood Volume after Cerebral Ischaemia

1986 ◽  
Vol 6 (3) ◽  
pp. 338-341 ◽  
Author(s):  
Nicholas V. Todd ◽  
Piero Picozzi ◽  
H. Alan Crockard
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Blood Volume ◽  
Quantitative Measurement ◽  
Cerebral Blood Volume ◽  
Vessel Occlusion ◽  
Permeability Surface ◽  
Area Product ◽  
Hydrogen Clearance ◽  
Clearance Technique

CBF obtained by the hydrogen clearance technique and cerebral blood volume (CBV) calculated from the [14C]dextran space were measured in three groups of rats subjected to temporary four-vessel occlusion to produce 15 min of ischaemia, followed by 60 min of reperfusion. In the control animals, mean CBF was 93 ± 6 ml 100 g−1 min−1, which fell to 5.5 ± 0.5 ml 100 g−1 min−1 during ischaemia. There was a marked early postischaemic hyperaemia (262 ± 18 ml 100g−1 min−1), but 1 h after the onset of ischaemia, there was a significant hypoperfusion (51 ± 3 ml 100 g−1 min−1). Mean cortical dextran space was 1.58 ± 0.09 ml 100 g−1 prior to ischaemia. Early in reperfusion there was a significant increase in CBV (1.85 ± 0.24 ml 100 g−1) with a decrease during the period of hypoperfusion (1.33 ± 0.03 ml 100 g−1). Therefore, following a period of temporary ischaemia, there are commensurate changes in CBF and CBV, and alterations in the permeability–surface area product at this time may be due to variations in surface area and not necessarily permeability.

scholarly journals A Clinical-Radiomics Nomogram Based on Computed Tomography for Predicting Risk of Local Recurrence After Radiotherapy in Nasopharyngeal Carcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Chaohua Zhu ◽  
Huixian Huang ◽  
Xu Liu ◽  
Hao Chen ◽  
Hailan Jiang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Computed Tomography ◽  
Nasopharyngeal Carcinoma ◽  
Local Recurrence ◽  
Stochastic Gradient Descent ◽  
Support Vector ◽  
Stable Model ◽  
Clinical Factors ◽  
Specificity And Sensitivity ◽  
Radiomics Signature

Purpose: We aimed to establish a nomogram model based on computed tomography (CT) imaging radiomic signature and clinical factors to predict the risk of local recurrence in nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT).Methods: This was a retrospective study consisting of 156 NPC patients treated with IMRT. Radiomics features were extracted from the gross tumor volume for nasopharynx (GTVnx) in pretreatment CT images for patients with or without local recurrence. Discriminative radiomics features were selected after t-test and the least absolute shrinkage and selection operator (LASSO) analysis. The most stable model was obtained to generate radiomics signature (Rad_Score) by using machine learning models including Logistic Regression, K-Nearest neighbor, Naive Bayes, Decision Tree, Stochastic Gradient Descent, Gradient Booting Tree and Linear Support Vector Classification. A nomogram for local recurrence was established based on Rad_Score and clinical factors. The predictive performance of nomogram was evaluated by discrimination ability and calibration ability. Decision Curve Analysis (DCA) was used to evaluate the clinical benefits of the multi-factor nomogram in predicting local recurrence after IMRT.Results: Local recurrence occurred in 42 patients. A total of 1,452 radiomics features were initially extracted and seven stable features finally selected after LASSO analysis were used for machine learning algorithm modeling to generate Rad_Score. The nomogram showed that the greater Rad_Score was associated with the higher risk of local recurrence. The concordance index, specificity and sensitivity in the training cohort were 0.931 (95%CI:0.8765–0.9856), 91.2 and 82.8%, respectively; whereas, in the validation cohort, they were 0.799 (95%CI: 0.6458–0.9515), 79.4, and 69.2%, respectively.Conclusion: The nomogram based on radiomics signature and clinical factors can predict the risk of local recurrence after IMRT in patients with NPC and provide evidence for early clinical intervention.

Increased Hepatocyte Permeability Surface Area Product for86Rb With Increase in Blood Flow

1997 ◽  
Vol 80 (5) ◽  
pp. 645-654 ◽  
Author(s):  
Carl A. Goresky ◽  
André Simard ◽  
Andreas J. Schwab
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Permeability Surface ◽  
Area Product

Use of [3H]methylglucose and [14C]iodoantipyrine to determine kinetic parameters of glucose transport in rat brain

1997 ◽  
Vol 272 (1) ◽  
pp. R163-R171
Author(s):  
K. Mori ◽  
M. Maeda
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Glucose Transport ◽  
Tissue Samples ◽  
Arterial Blood ◽  
Permeability Surface ◽  
Time Courses ◽  
Area Product ◽  
Menten Kinetic ◽  
The Brain

Local maximal velocities of transport (Tmax) and the half-maximum transport constants (KT) for glucose transport across the blood-brain barrier have been determined in local regions of the brain in normal conscious rats. [14C]iodoantipyrine and [3H]methylglucose were infused together intravenously for 2 min in rats with plasma glucose concentrations maintained at different levels, and the time courses of the tracer levels in arterial blood were measured. Local 14C and 3H concentrations were then measured in tissue samples dissected from the frozen brains. By comparing the transport-limited uptake of [3H]methylglucose with the blood flow-limited uptake of [14C]iodoantipyrine, the value of m, a factor between 0 and 10 that accounts for diffusion and/or transport limitations, was derived, and from the equation, m = 1 - PS/F (where PS is capillary permeability-surface area product and F is cerebral blood flow), the permeability-capillary surface area for methylglucose was calculated (S. S. Kety. Pharmacol. Rev. 3: 1-41, 1951). Values for Tmax and KT for glucose were calculated by application of Michaelis-Menten kinetic relationships adapted for the competition for transport between glucose and methylglucose. Tmax was determined in three representative gray structures and one white structure of the brain: Tmax was 5.3 +/- 0.3 (SD) mumol.g-1.min-1 in the gray structures and 4.3 mumol.g-1.min-1 in the white structure. KT was 3.6 +/- 0.4 (SD) mM in the gray structures and 5.9 mM in the white structure. This approach allows the simultaneous determination of local values of Tmax and KT for glucose and the rates of blood flow in various regions of the brain in conscious animals.

Regulation of jejunal blood flow and oxygenation during glucose and oleic acid absorption

1985 ◽  
Vol 249 (6) ◽  
pp. G691-G701 ◽  
Author(s):  
C. C. Chou ◽  
R. A. Nyhof ◽  
P. R. Kvietys ◽  
S. P. Sit ◽  
R. H. Gallavan
Keyword(s):  
Blood Flow ◽  
Oleic Acid ◽  
Glucose Absorption ◽  
O2 Uptake ◽  
Acid Absorption ◽  
Resistance Vessels ◽  
Permeability Surface ◽  
Anesthetized Dogs ◽  
Area Product ◽  
Oxygen Difference

To differentiate the mechanisms whereby actively absorbed glucose and passively absorbed oleic acid increase blood flow and oxygen uptake during their absorption, the effects of these two nutrients on jejunal blood flow, arteriovenous oxygen difference [(a-v)O2], O2 uptake, absorption, rubidium extraction, and capillary permeability-surface area product (PS) were compared in anesthetized dogs. Oleic acid (37 mM) produced significantly greater hyperemia (+28.2%) than glucose (270 mM) did (+12.5%). As estimated by (a-v)O2, tissue oxygen extraction was decreased by oleic acid (-12%) but increased by glucose (+6.5%); the increases in O2 uptake by these two nutrients did not differ significantly. Glucose absorption was accompanied by an increase in rubidium extraction and capillary PS (+11.3%), whereas oleic acid absorption was not. Unlike glucose, intra-arterial infusion of oleic acid decreased vascular resistance and increased blood flow equally to the mucosa and muscularis layers. A significant relation existed between oleic acid absorption and blood flow but not between glucose absorption and blood flow. The enhancement of glucose-induced hyperemia by bile was not related to glucose absorption. Unmasking of oleic acid-induced hyperemia by bile is unrelated to oleic acid absorption but is related to solubility of oleic acid in aqueous solution. The above findings suggest that glucose absorption affects both resistance and exchange vessels, whereas oleic acid absorption affects primarily resistance vessels.

scholarly journals Prophylactic Intra-Arterial Injection of Vasodilator for Asymptomatic Vasospasm Converts the Patient to Symptomatic Vasospasm due to Severe Microcirculatory Imbalance

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Norihito Shimamura ◽  
Masato Naraoka ◽  
Naoya Matsuda ◽  
Kiyohide Kakuta ◽  
Hiroki Ohkuma
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Carotid Artery ◽  
Internal Carotid ◽  
Mean Transit Time ◽  
Adequate Treatment ◽  
Time To Peak ◽  
Symptomatic Vasospasm ◽  
Angiographic Vasospasm ◽  
Time Density

Object. The strategy to treat asymptomatic angiographic vasospasm following subarachnoid hemorrhage (SAH) is controversial. In this study we review our consecutive vasospasm series and discuss an adequate treatment strategy for asymptomatic vasospasm.Methods. From January 2007 to December 2012 we treated 281 aneurysmal SAH cases, with postoperative angiography performed 9 ± 2 days after the onset of SAH. Four asymptomatic cases received intra-arterial (IA) injection of vasodilator due to angiographic vasospasm. All cases improved vasospasm immediately following intervention. But all cases turned symptomatic within 48 hours. We retrospectively analyzed the time-density angiography curve and calculated the time to peak (TTP), mean transit time (MTT), and relative blood flow (rBF). Relative blood flow was calculated as follows. The integration of the value of the time-density curve for the artery was divided by the same value for the internal carotid artery multiplied by the MTT.Results. The decrease in TTP and MTT for the etiologic artery was similar to that of the nonetiologic artery. But the improvement in rBF for the etiologic artery and nonetiologic artery was 10% and 17%, respectively. Blood supply to the spastic artery decreased due to iatrogenic steal.Conclusion. Prophylactic IA injection of vasodilator in cases of asymptomatic vasospasm can produce symptomatic vasospasm.

Role of capillary recruitment in the regulation of intestinal oxygenation

1982 ◽  
Vol 242 (5) ◽  
pp. G435-G441 ◽  
Author(s):  
A. P. Shepherd
Keyword(s):  
Blood Flow ◽  
Capillary Permeability ◽  
Capillary Density ◽  
Oxygen Extraction ◽  
Capillary Recruitment ◽  
Diffusion Limited ◽  
Permeability Surface ◽  
Capillary Exchange ◽  
Area Product

Increasing evidence indicates that capillary recruitment plays a significant role in regulating the oxygenation of intestinal tissue. Measurements of permeability-surface area product (PS) and capillary filtration coefficients (Kf) in isolated perfused gut loops indicate that changes in capillary density modulate oxygen extraction in a variety of experimental circumstances. Moreover, the intestinal microvasculature seems capable of independently regulating resistance and capillary exchange. Although "precapillary sphincters" have been identified in the intestine, the capillary density changes have not yet been confirmed by intravital microscopy, as they have been in skeletal muscle. Nevertheless, these changes in capillary density have quantitatively significant effects on oxygen extraction. For example, sympathetic stimulation depresses oxygen uptake in gut loops perfused at constant blood flow, presumably by reducing capillary density to such an extent that oxygen extraction becomes diffusion limited. The microvascular elements that control intestinal capillary density (presumably precapillary sphincters) are apparently under the control of neurogenic, myogenic, and local metabolic mechanisms, but the interaction among these mechanisms is poorly understood. In addition, the PS and Kf data, although well documented, could result from a redistribution of blood flow or an alteration in capillary permeability rather than a change in capillary density. Thus, the physiological mechanisms regulating capillary permeability and the intramural distribution of intestinal blood flow will have to be better understood before the role of capillary recruitment in regulating intestinal oxygenation will be firmly established.

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