Application Progress of Arterial Spin Labeling Magnetic Resonance Imaging in Renal Perfusion Analysis / 中国医学科学院学报

Arterial spin labeling is a noninvasive,quantitative method for perfusion imaging,which does not need any contrast media.This technique has been used in the renal perfusion analysis.In this article,we briefly introduced this technique and summarized its application in healthy volunteers,acute kidney injury,chronic kidney diseases,renovascular diseases,renal tumors,and renal transplantation.

Effect of the chemoprotectant tempol on anti-tumor activity of cisplatin / 南方医科大学学报

OBJECTIVE@#To investigate the effect of the chemoprotectant tempol on the anti-tumor activity of cisplatin (DDP).@*METHODS@#The cellular toxicity of tempol in human colon cancer SW480 cells and mouse colon cancer CT26 cells were evaluated using MTT and cell counting kit-8 assays. CalcuSyn software analysis was used to determine the interaction between tempol and DDP in inhibition of the cell viability. A subcutaneous homograft mouse model of colon cancer was established. The mice were randomly divided into control group, tempol group, cisplatin group and tempol + DDP treatment group with intraperitoneal injections of the indicated agents. The tumor size, body weight and lifespan of the mice were measured, and HE staining was used to analyze the cytotoxic effect of the agents on the kidney and liver. Immunohistochemistry and Western blotting were performed to detect the expression of Bax and Bcl2 in the tumor tissue, and TUNEL staining was used to analyze the tumor cell apoptosis. The level of reactive oxygen species (ROS) in the tumor tissue was determined using flow cytometry.@*RESULTS@#Tempol showed inhibitory effects on the viability of SW480 and CT26 cells. CalcuSyn software analysis showed that tempol had a synergistic anti-tumor effect with DDP (CI < 1). In the homograft mouse model, tempol treatment alone did not produce obvious anti-tumor effect. HE staining showed that the combined use of tempol and DDP alleviated DDP-induced fibrogenesis in the kidneys, but tempol also reduced the anti-tumor activity of DDP. Compared with the mice treated with DDP alone, the mice treated with both tempol and DDP had a significantly larger tumor size ( < 0.01) and a shorter lifespan ( < 0.05). Tempol significantly reversed DDP-induced expression of Bax and Bcl2 in the tumor tissue and tumor cell apoptosis ( < 0.001), and obviously reduced the elevation of ROS level in the tumor tissue induced by DDP treatment ( < 0.05).@*CONCLUSIONS@#Tempol can attenuate the anti-tumor effect of DDP while reducing the side effects of DDP. Caution must be taken and the risks and benefits should be carefully weighed when considering the use of tempol as an anti-oxidant to reduce the toxicities of DDP.

Cerebral blood flow and vasoreactivity in aging: an arterial spin labeling study

Regional cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in young and elderly participants were assessed using pulsed arterial spin labeling (ASL) and blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) techniques in combination with inhalation of CO2. Pulsed ASL and BOLD-MRI were acquired in seventeen asymptomatic volunteers (10 young adults, age: 30±7 years; 7 elderly adults, age: 64±8 years) with no history of diabetes, hypertension, and neurological diseases. Data from one elderly participant was excluded due to the incorrigible head motion. Average baseline CBF in gray matter was significantly reduced in elderly (46±9 mL·100 g-1·min-1) compared to young adults (57±8 mL·100 g-1·min-1; P=0.02). Decreased pulsed ASL-CVR and BOLD-CVR in gray matter were also observed in elderly (2.12±1.30 and 0.13±0.06 %/mmHg, respectively) compared to young adults (3.28±1.43 and 0.28±0.11 %/mmHg, respectively; P<0.05), suggesting some degree of vascular impairment with aging. Moreover, age-related decrease in baseline CBF was observed in different brain regions (inferior, middle and superior frontal gyri; precentral and postcentral gyri; superior temporal gyrus; cingulate gyri; insula, putamen, caudate, and supramarginal gyrus). In conclusion, CBF and CVR were successfully investigated using a protocol that causes minimal or no discomfort for the participants. Age-related decreases in baseline CBF and CVR were observed in the cerebral cortex, which may be related to the vulnerability for neurological disorders in aging.

Multi-parameter arterial spin labeling versus dynamic magnetic-sensitive enhanced cerebral perfusion imaging for diagnosis of transient cerebral ischemic attack / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the clinical value of three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) perfusion magnetic resonance imaging (MRI) and dynamic susceptibility contrast (DSC) enhanced perfusion MRI in the diagnosis of transient ischemic attack (TIA).</p><p><b>METHODS</b>Thirty-nine consecutive patients with suspected TIA underwent multi-modal MRI scans including DSC, magnetic resonance angiography (MRA), diffusion-weighted imaging (DWI) and 3D pCASL (post-labeling delay, PLD=1.5 s and 2.5 s) within 24 h of symptom onset. Cerebral blood flow (CBF) from ASL and the time to the maximum of tissue residual function (Tmax) map from DSC were calculated using AW workstation. DWI and MRA were applied to detect acute cerebral infarction and intracranial artery stenosis. Two neuroradilogists who were blinded to the patients' clinical data assessed the presence of perfusion deficit, ischemic lesion and the lesion sites both from 1.5 s, 2.5 s PLD ASL-CBF and DSC-Tmax independently, and then graded them. The differences in the ranking grades between 1.5 s, 2.5 s PLD ASL and DSC were analyzed, and the frequency of lesion detection was compared between ASL-CBF, Tmax and MRA combining DWI method.</p><p><b>RESULTS</b>No significant differences was found in hypoperfusion grades detected by 3D pCASL (including PLD1.5 s and 2.5 s) CBF and Tmax maps, while significant differences were detected between 1.5 s PLD ASL-CBF and MRA combining DWI method; ASL with PLD 1.5 s CBF detected ischemic lesions and lesion site significantly more frequently than MRA combining DWI method.</p><p><b>CONCLUSION</b>s Three dimensional pCASL is a non-invasive perfusion method free of radiation exposure, and short PLD ASL is more sensitive than long PLD ASL for detecting ischemic lesions and lesion sites.</p>

Quantitative Measurement of Cerebral Blood Flow in Enhanced Psedo-continuous Arterial Spin Labeling Perfusion Imaging in Patients with Intracranial Atherosclerotic Stenosis / 中国医学科学院学报

Objective To acquire cerebral blood flow (CBF) in patients with severe intracranial atherosclerotic stenosis with enhanced pseudo-continuous arterial spin labeling (e-pCASL) and compare it with the findings of dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC PWI) and pseudo-continuous arterial spin labeling (pCASL). Methods A total of 39 consecutive patients with severe intracranial atherosclerotic stenosis were enrolled in this study. All these patients underwent e-pCASL, pCASL, and DSC PWI. Blood supply territory of the stenosed artery was outlined as region of interest (ROI) and a mirror ROI was applied. Ratios of CBF were calculated as value of ROI/value of mirror ROI. SNK variance analysis was conducted to compare the CBF values of three persufion methods. Factorial analysis of variance and Pearson were employed to analysis the difference and the correlation of e-pCASL CBF ratio, pCASL CBF ratio, and DSC PWI relative cerebral blood flow(rCBF) ratio. Results The e-pCASL CBF ratio, pCASL CBF ratio, and DSC PWI rCBF ratio were not significantly different (P=0.476). TTP showed the CBF ratios were not significantly different between the healthy side and diseased side in patients with severe intracranial atherosclerotic stenosis. ATT showed the correlations of pCASL CBF ratio and DSC PWI rCBF ratio were not affected by ATT. Conclusions e-pCASL with multiple-post labeling delay time and pCASL have good consistency with DSC PWI in the quantitative measurement of hypoperfusion pattern. As an accurate, simple, non-invasive, and repeatable technique, e-pCASL has good correlation with DSC PWI in the quantitative measurement of hypoperfusion pattern that is not affected by ATT.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

Differential expression of immunologic proteins in gingiva after socket preservation in mini pigs

During healing following tooth extraction, inflammation and the immune response within the extraction socket are related to bone resorption. Objective : We sought to identify how the alloplastic material used for socket preservation affects the immune responses and osteoclastic activity within extraction sockets. Material and Methods : Using a porcine model, we extracted teeth and grafted biphasic calcium phosphate into the extraction sockets. We then performed a peptide analysis with samples of gingival tissue from adjacent to the sockets and compared the extraction only (EO) and extraction with socket preservation (SP) groups. We also used real-time polymerase chain reaction (PCR) to evaluate the expression level of immunoglobulins, chemokines and other factors related to osteoclastogenesis. Differences between the groups were analyzed for statistical significance using paired t tests. Results : Levels of IgM, IgG and IGL expression were higher in the EO group than in the SP group 1 week post-extraction, as were the levels of CCL3, CCL5, CXCL2, IFN-γ and TNF-α expression (p<0.05). In addition, receptor activator of nuclear factor kappa-B ligand (RANKL) was also significantly upregulated in the EO group (p<0.05), as were IL-1β, IL-6 and IL-8 (p<0.05). Conclusions : These results suggest that the beneficial effect of socket preservation can be explained by suppression of immune responses and inflammation. .

Role of renal sympathetic nerve and oxidative stress in foot shock-induced hypertension in rats / 生理学报

The present study was aimed to investigate the roles of renal sympathetic nerve and oxidative stress in the development of foot shock-induced hypertension. Ninety rats were divided into 6 groups (the number of each group was 15): control group, foot shock group, denervation of renal sympathetic nerve group, denervation of renal sympathetic nerve + foot shock group, Tempol treatment + foot shock group, denervation of renal sympathetic nerve + Tempol treatment + foot shock group. Rats were received electrical foot shock for 14 days (2-4 mA, 75 V, shocks of 50-100 ms every 30 s, for 4 h each session through an electrified grid floor every day). Renal sympathetic ablation was used to remove bilateral renal sympathetic nerve in rats (rats were allowed to recover for one week before the beginning of the foot shock procedure). The antioxidant Tempol was injected intraperitoneally at 1 h before foot shock. Systolic blood pressure was measured at 1 h after foot shock on day 0, 3, 7, 10 and 14. Contents of thiobarbituric acid reactive substance (TBARS), renin, angiotensin II (AngII) and glutathione peroxidase (GSH-Px) in plasma were measured by ELISA after 14-day foot shock. The results showed that systolic blood pressure of foot shock group was significantly increased (P < 0.05) compared with that of control group from day 7 to day 14 of foot shock. Denervation of renal sympathetic nerve and/or Tempol treatment significantly reduced the increase of systolic blood pressure induced by foot shock. Levels of TBARS, renin and AngII in plasma were increased significantly in foot shock group compared with that of control group (P < 0.05). Plasma GSH-Px concentration was decreased in foot shock group rats compared with that of control group (P < 0.05). Denervation of renal sympathetic nerve and/or tempol treatment significantly reduced the increase in TBARS, renin, AngII levels induced by foot shock in comparison with that of foot shock group (P < 0.05), but had no effects on the reduction of GSH-Px concentration. The results suggest that renal sympathetic nerve may play an important role in the development of foot shock-induced hypertension, and renal sympathetic nerve may influence oxidative stress and directly or indirectly activate renin-angiotensin-aldosterone system, so the foot shock-induced high blood pressure may be maintained and hypertension may therefore be produced.

Three-dimensional Pseudo-continuous Arterial Spin Label Non-contrast Enhanced Perfusion Imaging of Head and Neck Tumors with High-field MR System / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the feasibility of three-dimensional pseudo-continuous arterial spin label (3D pCASL) non-contrast enhanced perfusion imaging applied to head and neck tumors in high-field MR and detect the effects of different postlabeling delay (PLD) time on image quality and the reliability of repeated measurements of tumor blood flow (BF) in different 3D pCASL groups.</p><p><b>METHODS</b>In this prospective study,all the 25 patients received neck 3D pCASL non-contrast enhanced perfusion examinations in a 3.0 T MR system by using an 8-channel head and neck joint coil. Conventional T1-weighted (TIWI) and T2-weighted imaging (T2WI) were performed firstly. Finally,three 3D pCASL with different PLD time [ASL1(PLD1=1525 ms),ASL2 (PLD2=2025 ms), ASL3(PLD3=2525 ms)] were acquired. Patients' perfusion-weighted images acquired from different 3D pCASL sequences underwent the analysis of signal to noise ratio (SNR) and contrast noise ratio (CNR) for tumors. Two observers performed the qualitative assessments on spiral artifacts and vascular artifacts of perfusion-weighted images from different 3D pCASL sequences. Blood flow (BF) of tumors from different 3D pCASL sequences were measured by the two observers respectively for the first time and by observer 2 for the second time.</p><p><b>RESULTS</b>Seventeen enrolled patients (age:50.1 ± 12.7 years,M/F=10:7) with histopathologic.</p><p><b>RESULTS</b>underwent the evaluation of image quality and measurements of BF values. The SNRs and CNRs of ASL1,ASL2, and ASL3 showed a descending trendency. SNRs (P=0.011) and CNRs (P=0.009) of ASL1 were significant higher than those of ASL3. There was no significant difference of scores of spiral artifacts among the three ASL groups (P=0.932). The scores of vascular artifacts of ASL1,ASL2,and ASL3 showed a descending trendency,also. And scores of ASL1 was significant higher than that of ASL3(P=0.000). The intraclass correlation coefficient (ICC) of intre-and intraobserver were high (ICC>0.9). Although the BF values of ASL1,ASL2, and ASL3 showed an ascending trendency,there was no significant difference among the three groups (P=0.977).</p><p><b>CONCLUSIONS</b>The 3D pCASL no-contrast enhanced perfusion MR imaging can be used for head and neck tumor. The image quality of perfusion weighted images and reliability of BF measurements were satisfied. The 3D pCASL series with PLD of 1525 ms and 2025 ms have better image quality than PLD of 2525 ms. And BF values do not show significant statistic difference among the three groups. Therefore, 3D pCASL series with PLD of 1525 ms and 2025 ms are more suitable for the perfusion imaging of head and neck tumors</p>

Tendencias en la mortalidad por cáncer en México de 1980 a 2011 / Cancer mortality trends in Mexico, 1980-2011

Objetivo. Evaluar las tendencias de mortalidad por cáncer en México entre 1980 y 2011. Material y métodos. Se calcularon las tasas de mortalidad ajustadas por edad y sexo para todos los cánceres y para las 15 localizaciones más frecuentes mediante el método directo y tomando como población estándar la población mundial de 2010. Las tendencias en las tasas de mortalidad y el cambio porcentual anual para cada tipo de cáncer se estimaron a través de un modelo de regresión joinpoint. Resultados. A partir de 2004 y como consecuencia de la reducción de la mortalidad por cáncer de pulmón (-3.2% en hombres y -1.8% en mujeres), estómago (-2.1% en hombres y -2.4% en mujeres) y cérvix (-4.7%), se observó una disminución significativa (~1% anual) en la mortalidad por cáncer en general tanto en el grupo de todas las edades como en el de 35 a 64 años para ambos sexos. La mortalidad por otros cánceres como el de mama y el de ovario, en las mujeres o el de próstata, en los hombres, mostró un aumento sostenido. Conclusiones. Algunas de las reducciones en la mortalidad por cáncer pueden ser parcialmente atribuidas a la efectividad de los programas de prevención establecidos. Sin embargo, se requiere implementar registros adecuados de cáncer con base poblacional para evaluar el impacto real de estos programas, así como diseñar y evaluar intervenciones innovadoras que permitan desarrollar políticas de prevención más costo-efectivas.

Objective. To evaluate trends in cancer mortality in Mexico between 1980-2011. Material and methods. Through direct method and using World Population 2010 as standard population, mortality rates for all cancers and the 15 most frequent locations, adjusted for age and sex were calculated. Trends in mortality rates and annual percentage change for each type of cancer were estimated by joinpoint regression model. Results. As a result of the reduction in mortality from lung cancer (-3.2% -1.8% in men and in women), stomach (-2.1% -2.4% in men and in women) and cervix (-4.7%); since 2004 a significant (~1% per year) decline was observed in cancer mortality in general, in all ages, and in the group of 35-64 years of both sexes. Other cancers such as breast and ovarian cancer in women; as well as for prostate cancer in men, showed a steady increase. Conclusions. Some of the reductions in cancer mortality may be partially attributed to the effectiveness of prevention programs. However, adequate records of population-based cancer are needed to assess the real impact of these programs; as well as designing and evaluating innovative interventions to develop more cost-effective prevention policies.

Lipoic acid, but not tempol, preserves vascular compliance and decreases medial calcification in a model of elastocalcinosis

Vascular calcification decreases compliance and increases morbidity. Mechanisms of this process are unclear. The role of oxidative stress and effects of antioxidants have been poorly explored. We investigated effects of the antioxidants lipoic acid (LA) and tempol in a model of atherosclerosis associated with elastocalcinosis. Male New Zealand white rabbits (2.5-3.0 kg) were fed regular chow (controls) or a 0.5% cholesterol (chol) diet+104 IU/day vitamin D2 (vitD) for 12 weeks, and assigned to treatment with water (vehicle, n=20), 0.12 mmol·kg-1·day-1 LA (n=11) or 0.1 mmol·kg-1·day-1 tempol (n=15). Chol+vitD-fed rabbits developed atherosclerotic plaques associated with expansive remodeling, elastic fiber disruption, medial calcification, and increased aortic stiffness. Histologically, LA prevented medial calcification by ∼60% and aortic stiffening by ∼60%. LA also preserved responsiveness to constrictor agents, while intima-media thickening was increased. In contrast to LA, tempol was associated with increased plaque collagen content, medial calcification and aortic stiffness, and produced differential changes in vasoactive responses in the chol+vitD group. Both LA and tempol prevented superoxide signals with chol+vitD. However, only LA prevented hydrogen peroxide-related signals with chol+vitD, while tempol enhanced them. These data suggest that LA, opposite to tempol, can minimize calcification and compliance loss in elastocalcionosis by inhibition of hydrogen peroxide generation.

Hyperperfusion of multiple sclerosis plaques characterized by 3D FSE arterial spin labelling / 中国医学科学杂志(英文版)

Multiple sclerosis (MS) is a common inflammatory demyelinating disorder of central nervous system, and the disease burder could be well evaluated by conventional magnetic resonance imaging (MRI), including T2-weighted, fluid-attenuatd inversion recovery, and postcontrast T1-weighted sequences. We investigated the perfusion state of MS plaques using brain perfusion imaging in a 12-year-old boy with MS.

Effect of inhibiting brain reactive oxygen species on sympathetic nerve activity in DOCA-salt hypertensive rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate whether brain reactive oxygen species mediate sympathoexcitation and arterial pressure elevation in DOCA-salt hypertensive rats.</p><p><b>METHODS</b>DOCA-salt hypertensive model was established in male SD rats by subcutaneous injection of DOCA after uninephrectomy and drinking 1% NaCl solution for 4 weeks. The baseline mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded in the rats under mild anesthesia, and MAP changes following intravenous hexamethonium injection were observed. The responses of MAP, HR and RSNA to intracerebroventricular administration of tempol (20 µmol/L in 10 µl) were evaluated; plasma NE level was measured with ELISA, and ROS level and NAD(P)H oxidase activity in the hypothalamus were detected using chemiluminescence assay.</p><p><b>RESULTS</b>MAP and plasma NE levels were significantly increased in DOCA-salt rats as compared with those in the control group (P<0.01). In DOCA-salt hypertensive rats, intravenous hexamethonium injection induced a blood pressure reduction 240% of that in control rats, and significantly increased the levels of superoxide anion and NAD(P)H oxidase activity in the hypothalamus. Intracerebroventricular microinjection of tempol also resulted in more significant changes of MAP, HR and RSNA in DOCA-salt rats than in the control group (P<0.01).</p><p><b>CONCLUSION</b>Sympathoexcitation due to increased NAD(P)H oxidase-derived ROS levels in the hypothalamus may mediate arterial pressure elevation in DOCA-salt hypertensive rats.</p>

Perfusion Magnetic Resonance Imaging: A Comprehensive Update on Principles and Techniques

Perfusion is a fundamental biological function that refers to the delivery of oxygen and nutrients to tissue by means of blood flow. Perfusion MRI is sensitive to microvasculature and has been applied in a wide variety of clinical applications, including the classification of tumors, identification of stroke regions, and characterization of other diseases. Perfusion MRI techniques are classified with or without using an exogenous contrast agent. Bolus methods, with injections of a contrast agent, provide better sensitivity with higher spatial resolution, and are therefore more widely used in clinical applications. However, arterial spin-labeling methods provide a unique opportunity to measure cerebral blood flow without requiring an exogenous contrast agent and have better accuracy for quantification. Importantly, MRI-based perfusion measurements are minimally invasive overall, and do not use any radiation and radioisotopes. In this review, we describe the principles and techniques of perfusion MRI. This review summarizes comprehensive updated knowledge on the physical principles and techniques of perfusion MRI.

Tempol Attenuates Renal Fibrosis in Mice with Unilateral Ureteral Obstruction: The Role of PI3K-Akt-FoxO3a Signaling

This study investigated whether tempol, an anti-oxidant, protects against renal injury by modulating phosphatidylinositol 3-kinase (PI3K)-Akt-Forkhead homeobox O (FoxO) signaling. Mice received unilateral ureteral obstruction (UUO) surgery with or without administration of tempol. We evaluated renal damage, oxidative stress and the expression of PI3K, Akt, FoxO3a and their target molecules including manganese superoxide dismutase (MnSOD), catalase, Bax, and Bcl-2 on day 3 and day 7 after UUO. Tubulointerstitial fibrosis, collagen deposition, alpha-smooth muscle actin-positive area, and F4/80-positive macrophage infiltration were significantly lower in tempol-treated mice compared with control mice. The expression of PI3K, phosphorylated Akt, and phosphorylated FoxO3a markedly decreased in tempol-treated mice compared with control mice. Tempol prominently increased the expressions of MnSOD and catalase, and decreased the production of hydrogen peroxide and lipid peroxidation in the obstructed kidneys. Significantly less apoptosis, a lower ratio of Bax to Bcl-2 expression and fewer apoptotic cells in TUNEL staining, and decreased expression of transforming growth factor-beta1 were observed in the obstructed kidneys from tempol-treated mice compared with those from control mice. Tempol attenuates oxidative stress, inflammation, and fibrosis in the obstructed kidneys of UUO mice, and the modulation of PI3K-Akt-FoxO3a signaling may be involved in this pathogenesis.

Angiografía no contrastada con Arterial Spin Labeling / Non-contrast angioresonance with Arterial Spin Labeling

Introducción: La angiografía por resonancia magnética no contrastada realizada con "Arterial Spin Labeling" (ARM ASL) es un método diseñado para marcar los espines sanguíneos y así crear un contraste endógeno adecuado para evaluar territorios vasculares selectivamente sin la necesidad de aplicar medio de contraste intravenoso (compuestos de Gadolinio). Metodología: Se realizó un estudio descriptivo de una serie de casos, donde se describen los detalles técnicos y los resultados de la aplicación de la ARM ASL en equipos de 1.5 y 3 Tesla en voluntarios sanos. Resultados: Se observaron dos casos: Para la técnica angiográfica del primer caso (ASL "Flow-in") se usó un resonador de 3T, sincronización cardiaca, una secuencia b-SSFP 3D y un pre-pulso de inversión, este último para saturar los tejidos estáticos. El volumen de examen se ubicó en el plano axial teniendo la precaución de cubrir la anatomía vascular renal, lo cual se logra en la mayoría de los casos con 60 a 70 cortes de 2 mm solapados en 50 porciento, voxel de 2x1x1 mm y campo de visión (FOV) de 250x100 mm. El protocolo del segundo caso fue obtenido en un equipo de 1.5T, sin sincronización cardiaca, con un navegador respiratorio dia fragmático y con una secuencia coronal Turbo SE 3D después de aplicar dos pre-pulsos de marcación sanguínea, el primero similar al del caso anterior y el segundo, o pulso selectivo, para marcar el flujo del vaso de interés. Con este método (ASL "Flow-Out") sólo la sangre marcada emite señal. Conclusión: Las técnicas de angiografía b-SSFP 3D y Turbo SE 3D no contrastadas con pre-pulsos de ASL en 1.5 y 3T son alternativas disponibles y, por lo tanto, pueden considerarse como complemento a otros métodos de angiografía por resonancia magnética al momento de evaluar la patología vascular.

Introduction: Non-contrast magnetic resonance angiography using "Arterial Spin Labeling" (MRA ASL) is a technique designed to label blood spins and therefore create an endogenous contrast suitable for selectively evaluating vascular territories without intravenous contrast (Gadolinium compounds). Methodology: Technical details and results of the implementación of the MRA ASL using 1.5 and 3.0 Tesla systems in healthy volunteers is described. Results: Two cases were observed: for the angiographic technique of the first case (ASL "Flow-in") in a 3.0 T unit, cardiac synchronization (cardiac gating), a 3D b-SSFP sequence, and an inversion pre-pulse was used, the latter to saturate the static tissues. The examination volume was located in the axial plane taking care to cover the renal vascular anatomy, which is achieved in most cases with 60 to 70 2 mm slices overlapped in 50%, voxel of 2x1x1 mm and a field of vision (FOV) of 250 x100 mm. The protocol for the second case was obtained on a 1.5 T system, without cardiac gating, with a diaphragmatic respiratory navigator and a 3D Turbo SE coronal sequence after applying two pre-pulse blood saturation bands, the first similar to the previous case and the second, or selective pulse, to label the flow of the vessel of interest. With this method (ASL "Flow-Out") only the labeled blood emits a signal. Discussion: 3D b-SSFP and 3D Turbo SE non-contrast angiography techniques with ASL pre-pulses in 1.5 and 3T are available alternatives and, therefore, can be considered as a complement to other methods of magnetic resonance angiography when assessing vascular pathology.

Clinical applications of arterial spin labeling technique in brain diseases / 生物医学工程学杂志

Arterial spin labeling (ASL) technique is a kind of perfusion functional magnetic resonance imaging method that is based on endogenous contrast, and it can measure cerebral blood flow (CBF) noninvasively. The ASL technique has advantages of noninvasiveness, simplicity and relatively lower costs so that it is more suitable for longitudinal studies compared with previous perfusion methods, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), CT and the contrast agent based magnetic resonance perfusion imaging. This paper mainly discusses the current clinical applications of ASL in brain diseases as cerebrovascular diseases, brain tumors, Alzheimer's disease and epilepsy, etc.

Analysis of arterial spin labeling in 33 patients with hypoxic ischemic encephalopathy / 中华儿科杂志

<p><b>OBJECTIVES</b>To evaluate the diagnostic value of arterial spin labeling (ASL) technology in newborns with hypoxic ischemic encephalopathy (HIE).</p><p><b>METHOD</b>Seven full-term newborn infants without any history of asphyxia and other nervous system diseases were selected as the control and 33 full-term newborn infants were assigned into HIE group. The patients in HIE group were further divided into three subgroups (19 cases of mild, 6 cases of moderate and 8 cases of severe HIE) based on their clinical diagnosis. The control group and HIE group were examined with GE Signa EXCITE HD 3.0T superconducting MRI scanner with a head phase array coil. Both groups were scanned with conventional axial MRI (T1FLAIR, T2WI and T2FLAIR), 1HMRS (PRESS sequence) and ASL (FAIR). Original images of 1HMRS and ASL were processed by Functool software of ADW 4.3 workstation. ASL perfusion images were observed and the signal intensity values of the region of interest (bilateral gray, white matter and basal ganglia) of the two groups were quantitatively measured, and mean value were calculated and compared between groups. Statistical analysis was performed with SPSS 13.0 software, and statistically significant difference was set at P < 0.05.</p><p><b>RESULT</b>The perfusion images of two groups were obtained perfectly. The signal intensity values of bilateral gray, white matter and basal ganglia of control group were 125.34 ± 11.76, 73.42 ± 11.67 and 173.65 ± 15.49, respectively and there was a statistically significant difference between the different areas. The signal intensity values of bilateral gray, white matter and basal ganglia of HIE group were 153.47 ± 11.72, 71.35 ± 10.37 and 217.13 ± 12.51, respectively. There was a statistically significant difference (P < 0.05) in the average signal intensity value of gray matter and basal ganglia, but there were no statistically significant difference (P > 0.05) in white matter between the two groups.</p><p><b>CONCLUSION</b>ASL Perfusion technique can assess HIE comprehensively and accurately. Furthermore, it can evaluate the brain damage of hypoxic ischemia. The results provide a strong basis for clinical treatment.</p>

Determination of the rCBF in the Amygdala and Rhinal Cortex Using a FAIR-TrueFISP Sequence

OBJECTIVE: Brain perfusion can be assessed non-invasively by modern arterial spin labeling MRI. The FAIR (flow-sensitive alternating inversion recovery)-TrueFISP (true fast imaging in steady precession) technique was applied for regional assessment of cerebral blood flow in brain areas close to the skull base, since this approach provides low sensitivity to magnetic susceptibility effects. The investigation of the rhinal cortex and the amygdala is a potentially important feature for the diagnosis and research on dementia in its early stages. MATERIALS AND METHODS: Twenty-three subjects with no structural or psychological impairment were investigated. FAIR-True-FISP quantitative perfusion data were evaluated in the amygdala on both sides and in the pons. A preparation of the radiofrequency FOCI (frequency offset corrected inversion) pulse was used for slice selective inversion. After a time delay of 1.2 sec, data acquisition began. Imaging slice thickness was 5 mm and inversion slab thickness for slice selective inversion was 12.5 mm. Image matrix size for perfusion images was 64 x 64 with a field of view of 256 x 256 mm, resulting in a spatial resolution of 4 x 4 x 5 mm. Repetition time was 4.8 ms; echo time was 2.4 ms. Acquisition time for the 50 sets of FAIR images was 6:56 min. Data were compared with perfusion data from the literature. RESULTS: Perfusion values in the right amygdala, left amygdala and pons were 65.2 (+/- 18.2) mL/100 g/minute, 64.6 (+/- 21.0) mL/100 g/minute, and 74.4 (+/- 19.3) mL/100 g/minute, respectively. These values were higher than formerly published data using continuous arterial spin labeling but similar to 15O-PET (oxygen-15 positron emission tomography) data. CONCLUSION: The FAIR-TrueFISP approach is feasible for the quantitative assessment of perfusion in the amygdala. Data are comparable with formerly published data from the literature. The applied technique provided excellent image quality, even for brain regions located at the skull base in the vicinity of marked susceptibility steps.

[Effects of tempol on in vitro development of mouse embryos under oxidative stress]

Etiologically, oxidative stress can be considered as one of the reasons for defective embryonic development which leads to developmental arrest due to necrosis or apoptosis. Under in vivo conditions, multiple mechanisms act to protect the embryo against reactive oxygen species [ROS], but under in vitro conditions most of these mechanisms are absent leading to higher levels of ROS in the culture medium. The objective of this study was to compare the antioxidant effects of Tempol, 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-l-oxyl, a permeable synthetic antioxidant, on mouse preimplantation embryonic development in vitro conditions in the presence or absence of oxidative stress. Mature oocytes from mouse were retrieved following ovarian stimulation by the administration of Pregnant Mare Serum Gonadotropin [PMSG] and hCG. Upon in vitro fertilization, the zygotes were cultured in different groups in HTF medium containing 4 mg/ml BSA. To study the effects of oxidative stress on embryo development, the zygotes were cultured for an hour in a medium containing different concentrations of H[2]O[2]. After washing, the zygotes were transferred to the culture plate. The zygotes were later placed in the media containing different concentrations of Tempol following their culture in 10 microM H[2]O[2] for one hour to study the effects of different concentrations of the substance in the absence of other oxidative stresses. The data were later compared and statistically analyzed. The pre-implantation embryonic development decreased significantly in the case group, compared to the control group after a short exposure to H[2]O[2], - the effect being more noticeable in higher concentrations. Tempol reduced the impairments resulting from the oxidative stress to some extent. Under in vitro conditions and a concentration of 0.5 microM, Tempol improved embryonic development quality, quantitatively and morphologically. Tempol increased the percentage of two-cell embryos from 91.78% in the control group to 96.99% [p < 0.05], blastocysts from 67.80% in the controls to 81.33% [p < 0.05] in the cases, and significantly decreased embryonic arrest from 32.19% in the controls to 18.67% in the cases [p < 0.05]. ROS has a major role in embryonic arrest, witnessed in embryo cultures in vitro conditions. The present study showed that supplementation of embryo cultures with Tempol improved the embryonic development. It seems that addition of permeable synthetic antioxidants, such as Tempol, to embryo cultures could protect embryos from oxidative damage and improve embryonic development