Echo train shifted multi-echo FLASH for functional MRI of the human brain at ultra-high spatial resolution

This paper describes the development of a novel technique for functional MRI of the human brain at 0.135 microL resolution for a whole brain section. In comparison with conventional studies at 3 mm isotropic resolution or 27 microL voxel size, the method yields an improvement by a factor of 200. To achieve optimum image quality, the approach is based on a multi-echo fast low-angle shot (FLASH) sequence with unipolar traversals of k-space in the frequency-encoding dimension and echo train shifting to avoid amplitude discontinuities in the phase-encoding dimension. These strategies ensure a smooth point-spread function and eliminate image ghosting artifacts without the need for any phase correction or other post-processing. Signal-to-noise losses due to the considerably reduced voxel sizes are compensated for by single slice acquisitions, optimized bandwidths and an experimental four-channel shoulder coil matched to the posterior portion of the head. Multi-echo FLASH studies of the human brain (2.9 T, seven echoes, 200 Hz/pixel bandwidth, effective echo time 36 ms, acquisition time 6 s) at 300 microm resolution (no interpolation) and 1.5 mm slice thickness revealed robust activations in primary visual areas in response to binocular stimulation. The new method holds promise for refined studies of the columnar organization of specific brain systems and for functional assessments of the gray matter at laminar resolution.     

In vivo brain (31)P-MRS: measuring the phospholipid resonances at 4 Tesla from small voxels

An optimized phosphorous ((31)P) three-dimensional chemical-shift imaging (3D-CSI) protocol was developed at 4 T to study the phospholipid metabolism from discrete regions in the human brain without the need for (1)H-decoupling or nuclear Overhauser enhancement (NOE). In this study, a spherically bound, weighted average, random point omission 3D-CSI technique was developed and tested, based on methods proposed in the literature. The technique yields a significant (p < 0.001, two-tailed, 5% confidence level) increase in signal-to-noise (SNR) efficiency over conventional 3D-CSI (phantom 32%), without an increase in voxel bleedthrough. An automated time-domain fitting procedure utilizing prior spectral knowledge quantified the individual brain phospholipid metabolites from 15 cm(3) effective (8.0 cm(3) nominal) volumes from the left/right-parieto-occipital cortex and left/right thalamus in 10 normal volunteers. Individual constituents from the phosphomonoester (PME) region; phosphoethanolamine (PEth), phosphocholine (PCh) and the phosphodiester (PDE) region; glycerophosphoethanolamine (GPEth), glycerophosphocholine (GPCh) and membrane phospholipids (MP) were separately quantified to assess the precision of our method at 4 T against previous (1)H-decoupled (31)P-MRS brain studies at lower fields and much larger voxels. Derived concentrations (mM/l tissue) for PEth, PCh, GPEth, GPCh and MP in the left-parieto-occipital cortex were 0.81 +/- 0.21, 0.46 +/- 0.14, 0.74 +/- 0.30, 1.15 +/- 0.43 and 1.54 +/- 0.95 mM, respectively, and 0.94 +/- 0.16, 0.46 +/- 0.17, 0.83 +/- 0.22, 1.14 +/- 0.40 and 1.26 +/- 0.78 mM for the right parieto-occipital cortex. Derived concentrations (mM/l tissue) for PEth, PCh, GPEth, GPCh and MP in the left-thalamus were 0.69 +/- 0.18, 0.42 +/- 0.16, 0.63 +/- 0.20, 1.05 +/- 0.42 and 0.93 +/- 0.56 mM, respectively, and 0.68 +/- 0.24, 0.34 +/- 0.18, 0.60 +/- 0.23, 1.09 +/- 0.36 and 0.74 +/- 0.48 mM for the right-thalamus. This is the first study to our knowledge that has been able to quantify each of these individual phospholipid metabolites from such small voxels in the brain within a clinically reasonable scan time and without (1)H-decoupling or NOE.     

High resolution MRI evaluation of meniscal volume and anthropometric correlations

The purpose of this study was to digitally determine meniscal volumes, and compare them with linear and surface area anthropometric measurements to evaluate these measurements for meniscal allograft sizing. Eighteen subjects (10 male and 8 female; mean age 37.5 years) underwent 3.0 T knee magnetic resonance imaging (MRI) of the dominant leg. The following morphometric measurements were evaluated: medial meniscal volume (MMV), lateral meniscal volume (LMV), tibial plateau width (TPW), width of the femoral condyles (WFC), and tibial plateau surface area (TPSA). MMV and LMV were compared to TPW, WFC, and TPSA. Meniscal volume and TPW were correlated to height and body‐mass index (BMI) and stratified by gender. Statistical analysis included coefficient of determination (r²) between MRI‐based MMV, LMV, TPW, TPSA, WFC, height, BMI, and gender. Significance was set at the P = 0.05 level. The mean MMV was 2275 mm³ and the mean LMV was 2102 mm³. TPW correlated well with meniscal volumes (r² > 0.62). WFC and TPSA correlated with meniscal volumes in the range of 0.40 < r² < 0.61. Height, BMI, and gender correlated poorly with total meniscal volume and TPW with values of r² < 0.44. Medial and lateral menisci have statistically similar volumes. TPW had the greatest utility for volumetric meniscal sizing. MRI‐based TPW can be considered as a statistically accurate measurement for determining meniscal volumes and meniscal size. Clin. Anat. 28:786–791, 2015. © 2015 Wiley Periodicals, Inc.     

MRI of atherosclerosis in clinical trials

Magnetic resonance imaging (MRI) of the arterial wall has emerged as a viable technology for characterizing atherosclerotic lesions in vivo, especially within carotid arteries and other large vessels. This capability has facilitated the use of carotid MRI in clinical trials to evaluate therapeutic effects on atherosclerotic lesions themselves. MRI is specifically able to characterize three important aspects of the lesion: size, composition and biological activity. Lesion size, expressed as a total wall volume, may be more sensitive than maximal vessel narrowing (stenosis) as a measure of therapeutic effects, as it reflects changes along the entire length of the lesion and accounts for vessel remodeling. Lesion composition (e.g. lipid, fibrous and calcified content) may reflect therapeutic effects that do not alter lesion size or stenosis, but cause a transition from a vulnerable plaque composition to a more stable one. Biological activity, most notably inflammation, is an emerging target for imaging that is thought to destabilize plaque and which may be a systemic marker of vulnerability. The ability of MRI to characterize each of these features in carotid atherosclerotic lesions gives it the potential, under certain circumstances, to replace traditional trials involving large numbers of subjects and hard end-points--heart attacks and strokes--with smaller, shorter trials involving imaging end-points. In this review, the state of the art in MRI of atherosclerosis is presented in terms of hardware, image acquisition protocols and post-processing. Also, the results of validation studies for measuring lesion size, composition and inflammation will be summarized. Finally, the status of several clinical trials involving MRI of atherosclerosis will be reviewed.     

High‐resolution MRI analysis of breast cancer xenograft on the chick chorioallantoic membrane

The chick chorioallantoic membrane (CAM) model has been successfully used to study angiogenesis, cancer progression and its pharmacological treatment, tumor pharmacokinetics, and properties of novel nanomaterials. MRI is an attractive technique for non‐invasive and longitudinal monitoring of physiological processes and tumor growth. This study proposes an age‐adapted cooling regime for immobilization of the chick embryo, enabling high‐resolution MRI of the embryo and the CAM tumor xenograft. 64 chick embryos were enrolled in this study. The novel immobilization and imaging protocol was optimized in 29 embryos. From d7 to d18 immobilization of the embryo up to 90 min was achieved by cooling at 4 °C pre‐imaging, with cooling times adapted to age. Its application to tumor growth monitoring was evaluated in 15 embryos after xenotransplantation of human MDA‐MB‐231 breast cancer cells on CAM. Tumor volumes were monitored from d4 to d9 after grafting (d11 to d16 after incubation) applying a T₂‐weighted multislice RARE sequence. At d9 after grafting, the tumors were collected and compared with the MRI‐derived data by histology and weight measurements. Additional imaging methods comprising DWI, T₂ mapping, and the bio‐distribution of contrast agents were tested at d9 after grafting in 20 further embryos. With the adaptive cooling regime, motion artifacts could be completely avoided for up to 90 min scan time, enabling high‐resolution in ovo imaging. Excellent anatomical details could be obtained in the embryo and tumors. Tumor volumes could be quantified over time. The results prove the feasibility of high‐resolution MRI for longitudinal tumor and organ growth monitoring. The suggested method is promising for future applications such as testing tailored and/or targeted treatment strategies, longitudinal monitoring of tumor development, analysis of therapeutic efficacies of drugs, or assessment of tumor pharmacokinetics. The method provides an alternative to animal experimentation. Copyright © 2015 John Wiley & Sons, Ltd.     

Direct comparison of high‐temporal‐resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice

Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one‐dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high‐temporal‐resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user‐independent technique. Here, we investigated the performance of high‐temporal‐resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in‐house, high‐temporal‐resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom‐made, open‐source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high‐frequency, pulsed‐wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high‐temporal‐resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high‐temporal‐resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high‐temporal‐resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression.     

3.0T 3D-TOF MRA对颅内动脉瘤检出率的临床应用研究

目的评价3.0 T时间飞跃法磁共振血管成像(3.0 T 3D-TOF MRA)对颅内动脉瘤的诊断价值。方法选择25例有颅内动脉瘤相关症状患者,其中男性14例,女性11例;年龄25～74岁,平均年龄57岁。对其3.0 T 3D-TOF MRA诊断为颅内动脉瘤患者的磁共振资料进行回顾性分析,并与数字减影血管造影(DSA)对照。结果3.0 T 3D-TOF MRA共显示28个动脉瘤,其中单发22例,3例为多发动脉瘤,起自颈内动脉系统25个;起自基底动脉系统3个;DSA检查共显示27个动脉瘤。结论3.0 T 3D-TOF MRA虽然对于直径≤3 mm的微小动脉瘤的诊断存在一定的误诊及漏诊率,但其诊断颅内动脉瘤时能比较全面地显示动脉瘤,三维信息对临床确立治疗方案有很大帮助。3.0 T 3D-TOF MRA不失为高危人群或临床怀疑颅内动脉瘤患者筛查及随诊观察的有效手段。     

Higher spatial resolution improves the interpretation of the extent of ventricular trabeculation

The ventricular walls of the human heart comprise an outer compact layer and an inner trabecular layer. In the context of an increased pre‐test probability, diagnosis left ventricular noncompaction cardiomyopathy is given when the left ventricle is excessively trabeculated in volume (trabecular vol >25% of total LV wall volume) or thickness (trabecular/compact (T/C) >2.3). Here, we investigated whether higher spatial resolution affects the detection of trabeculation and thus the assessment of normal and excessively trabeculated wall morphology. First, we screened left ventricles in 1112 post‐natal autopsy hearts. We identified five excessively trabeculated hearts and this low prevalence of excessive trabeculation is in agreement with pathology reports but contrasts the prevalence of approximately 10% of the population found by in vivo non‐invasive imaging. Using macroscopy, histology and low‐ and high‐resolution MRI, the five excessively trabeculated hearts were compared with six normal hearts and seven abnormally trabeculated and excessive trabeculation‐negative hearts. Some abnormally trabeculated hearts could be considered excessively trabeculated macroscopically because of a trabecular outflow or an excessive number of trabeculations, but they were excessive trabeculation‐negative when assessed with MRI‐based measurements (T/C <2.3 and vol <25%). The number of detected trabeculations and T/C ratio were positively correlated with higher spatial resolution. Using measurements on high resolution MRI and with histological validation, we could not replicate the correlation between trabeculations of the left and right ventricle that has been previously reported. In conclusion, higher spatial resolution may affect the sensitivity of diagnostic measurements and in addition could allow for novel measurements such as counting of trabeculations.     

Modeling dynamic cerebral blood volume changes during brain activation on the basis of the blood-nulled functional MRI signal

Recently, vascular space occupancy (VASO) based functional magnetic resonance imaging (fMRI) was proposed to detect dynamic cerebral blood volume (CBV) changes using the blood-nulled non-selective inversion recovery (NSIR) sequence. However, directly mapping the dynamic CBV change by the NSIR signal change is based on the assumption of slow water exchange (SWE) around the capillary regime without cerebral blood flow (CBF) effects. In the present study, a fast water exchange (FWE) model incorporating with flow effects was derived from the Bloch equations and implemented for the quantification of dynamic CBV changes using VASO-fMRI during brain activation. Simulated results showed that only subtle differences in CBV changes estimated by these two models were observed on the basis of previously published VASO results. The influence of related physiological and biophysical factors within typical ranges was evaluated in steady-state simulations. It was revealed that in the transient state the CBV curves could be delayed in comparison with measured NSIR curves owing to the imbalance between the inflowing and outflowing blood signals.     

磁共振成像DWI联合3D-ASL对急性脑梗死的诊断效能及在血流动力学评估中的应用

目的:探讨磁共振成像（MRI）DWI联合3D-ASL对急性脑梗死（ACI）的诊断效能及在血流动力学评估中的应用价值。方法:收集因ACI就诊的80例患者的临床资料,全部入选者均接受1.5T/3.0T MRI进行扫描,分别分析患者脑梗死的DWI、3D-ASL图像表现,并评估DWI联合3D-ASL检查ACI是否具有更高的诊断价值。结果:有49例ACI患者在DWI图像上显示为弥散受限,面积为（673±319） mm2,68例患者在3D-ASL图像上显示为低灌注,低灌注面积为（1 953±803） mm2,其中面积ASL>面积DWI的患者有62例,存在缺血半暗带。在DWI图像上显示为弥散受限的患者中,左侧高信号者的CBF绝对值均低于右侧（22.34±4.36 vs 40.58±9.01, P<0.001）,右侧高信号者的CBF绝对值均低于左侧（19.48±5.67 vs 46.01±11.15, P<0.001）。DWI联合3D-ASL检查诊断ACI的灵敏度、特异度、阳性预测值和阴性预测值均高于单独DWI检查。结论:DWI联合3D-ASL检查评估ACI中梗死灶和缺血半暗带具有很大的应用价值。     

脊髓型颈椎病高场强磁共振成像探讨

目的 研究脊髓型颈椎病(CSM)的MRI成像特点及其临床意义。方法 分析主诉有颈肩痛或／和肢体麻木、乏力就诊者134例，经诊断CSM者80例，并根据临床表现分组比较MRI表现。结果 非CSM者MRI表现出椎间盘变性或轻度突出、骨赘形成但不构成对脊髓压迫；CSM病例表现不同程度椎间盘突出、椎体后缘骨赘形成及硬膜囊和脊髓受压，其中69例(86．25％，)脊髓受压，11例(13．75％)脊髓受压变性。临床症状严重者，MRI表现出颈髓变性显著增多，术后脊髓变性信号仍存在。结论 高场强MRI可良好显示CSM中椎间盘退变突出、骨赘形成及脊髓受压变性，为临床诊断与外科治疗提供依据。     

Identification of MRI and 1H MRSI parameters that may predict survival for patients with malignant gliomas

Although MR imaging (MRI) and MR spectroscopic imaging (MRSI) have been applied in the diagnosis and treatment planning for brain tumors, their prognostic significance has not yet been determined. The goal of this study was to identify pre-treatment MRI and MRSI parameters for patients with malignant glioma that may be useful in predicting survival. Two populations of patients with newly-diagnosed malignant glioma were examined with MRI and three-dimensional proton ((1)H) MRSI. Thirty-nine patients (22 grade 3 and 17 glioblastoma multiforme, GBM) were studied prior to surgery, and 33 GBM patients were studied after surgery but prior to treatment with radiation and chemotherapy. Signal intensities of choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), and lactate/lipid (LL) were estimated from the spectra. Recursive partitioning methods were applied to parameters that included age, histological grade, MRI and MRSI variables to generate survival trees. Patients were grouped into high and low risk categories and the corresponding Kaplan-Meier curves were plotted for comparison between groups. The parameters that were selected by recursive partitioning as being predictive of poor outcome were older age, larger contrast enhancement, higher Cho-to-Cr, higher Cho-to-NAA, higher LL and lower Cr-to-NAA abnormalities. The survival functions were significantly different between the sub-groups of patients obtained from the survival tree for both pre-surgery and post-surgery data. The results of this study suggest that pre-treatment MRI and three-dimensional (1)H-MRSI provide information that predicts outcome for patients with malignant gliomas and have drawn attention to variables that should be examined prospectively in future studies using these techniques.     

Improved Assessment of Ex Vivo Brainstem Neuroanatomy With High‐Resolution MRI and DTI at 7 Tesla

The aim of the present work was to provide the topography of the main gray nuclei and white matter tracts of the human brainstem at 7 Tesla (7 T) high‐field magnetic resonance imaging (MRI) using structural imaging (T1) and diffusion tensor imaging (DTI). Both imaging techniques represent a new field of increasing interest for its potential neuroanatomic and neuropathologic value. Brainstems were obtained postmortem from human donors, fixated by intracarotid perfusion of 10% neutral buffered formalin, and scanned in a Bruker BioSpec 7 T horizontal scanner. 3D‐data sets were acquired using the modified driven equilibrium Fourier transform (MDEFT) sequence and Spin Echo‐DTI (SE‐DTI) sequence was used for DTI acquisition. High‐resolution structural MRI and DTI of the human brainstem acquired postmortem reveals its basic cyto‐ and myeloar‐chitectonic organization, only visualized to this moment by histological techniques and higher magnetic field strengths. Brainstem structures that are usually not observed with lower magnetic fields were now topographically identified at midbrain, pons, and medullar levels. The application of high‐resolution structural MRI will contribute to precisely determine the extension and topography of brain lesions. Indeed, the current findings will be useful to interpret future high‐resolution in vivo MRI studies in living humans. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

Evaluation of segmented 3D acquisition schemes for whole‐brain high‐resolution arterial spin labeling at 3 T

Recent technical developments have significantly increased the signal‐to‐noise ratio (SNR) of arterial spin labeled (ASL) perfusion MRI. Despite this, typical ASL acquisitions still employ large voxel sizes. The purpose of this work was to implement and evaluate two ASL sequences optimized for whole‐brain high‐resolution perfusion imaging, combining pseudo‐continuous ASL (pCASL), background suppression (BS) and 3D segmented readouts, with different in‐plane k‐space trajectories. Identical labeling and BS pulses were implemented for both sequences. Two segmented 3D readout schemes with different in‐plane trajectories were compared: Cartesian (3D GRASE) and spiral (3D RARE Stack‐Of‐Spirals). High‐resolution perfusion images (2 × 2 × 4 mm³) were acquired in 15 young healthy volunteers with the two ASL sequences at 3 T. The quality of the perfusion maps was evaluated in terms of SNR and gray‐to‐white matter contrast. Point‐spread‐function simulations were carried out to assess the impact of readout differences on the effective resolution. The combination of pCASL, in‐plane segmented 3D readouts and BS provided high‐SNR high‐resolution ASL perfusion images of the whole brain. Although both sequences produced excellent image quality, the 3D RARE Stack‐Of‐Spirals readout yielded higher temporal and spatial SNR than 3D GRASE (spatial SNR = 8.5 ± 2.8 and 3.7 ± 1.4; temporal SNR = 27.4 ± 12.5 and 15.6 ± 7.6, respectively) and decreased through‐plane blurring due to its inherent oversampling of the central k‐space region, its reduced effective T_E and shorter total readout time, at the expense of a slight increase in the effective in‐plane voxel size. Copyright © 2014 John Wiley & Sons, Ltd.     

Spectrally inhomogeneous BOLD contrast changes detected in rodent tumors with high spectral and spatial resolution MRI

MRI detects changes in blood-oxygenation-level dependent (BOLD) contrast in tumors caused by tumor oxygenating agents. These changes can be used to guide the design of improved tumor oxygenating treatments (TOXs). The conventional approach to detection of BOLD effects assumes that the water resonance is a single, homogeneously broadened Lorentzian line, and that changes in the T2* of this line owing to changes in deoxyhemoglobin are spectrally homogeneous. This model may not adequately describe BOLD contrast changes in complex water resonances that are often detected in tumors. The present work investigated: (a) whether changes in the water resonance in very small voxels caused by tumor oxygenating agents are spectrally inhomogeneous; and (b) whether high spectral and spatial resolution (HiSS) MRI of the water and fat resonances detects these changes more accurately than conventional gradient-recalled echo (GRE) imaging. Carbogen (95% oxygen, 5% CO2) was used to increase tumor oxygenation. In two tumor models [mammary adenocarcinoma (R3230Ac; n=5) and rhabdomyosarcoma (BA1112; n=5)] proton signals were often complex and inhomogeneously broadened. Spectrally inhomogeneous changes during carbogen breathing occurred in at least 10% of the R3230AC tumor voxels that responded to carbogen and 18% of BA1112 tumor voxels. The largest changes during carbogen breathing in many voxels occurred at frequencies that were significantly different from the frequency of the primary water peak. Carbogen-induced changes in proton T2* detected by simulated GRE and HiSS differed by more than 75% in 67% of voxels in R3230Ac tumors and in 65% of voxels in BA1112 tumors. The spectrally inhomogeneous effects of tumor oxygenating agents may reflect changes in sub-voxelar microenvironements and thus may be important for accurate evaluation of the effects of therapy.     

Mean cerebral blood flow measurements using phase contrast MRI in the first year of life

Alterations in cerebral blood flow (CBF) are believed to be linked to many of the neurological pathologies that affect neonates and small infants. CBF measurements are nonetheless often difficult to perform in this population, as many techniques rely on radioactive tracers or other invasive methods. In this study, mean global CBF was measured in 21 infants under the age of one, using non-invasive MRI techniques adapted to the neonatal population. Mean CBF was computed as the ratio of blood flow delivered to the brain (measured using phase contrast MRI) and brain volume (computed by segmenting anatomical MR images). Tests in adult volunteers and repeated measurements showed the flow measurements using the proposed method to be both accurate and reproducible. It was also found that cardiac gating need not be employed in infants with no known cardiac pathology. The developed technique can easily be appended to a neonatal MRI examination to provide rapid, robust, and non-invasive estimates of mean CBF, thus providing a means to monitor developmental or pathology-related alterations in cerebral perfusion and the impact of different treatment courses. In the imaged cohort, mean CBF and flow to the brain were found to rapidly increase during the first year of life (from approx. 25 to 60 ml blood/100 ml tissue/min), in good agreement with literature from other modalities where available. Mean CBF also showed a significant correlation with arterial oxygen saturation level and heart rate, but no significant correlation was found between CBF and the hematocrit or body temperature.     

眼球和颅内恶性黑色素瘤的MRI表现

目的回顾性分析12例恶性黑色素瘤的MRI表现,提高对恶性黑色素瘤的影像学认识。方法选取2006年3月-2008年5月经病理学诊断证实的恶性黑色素瘤12例,其中女性5例,男性7例,年龄42～76岁,平均年龄56．5岁。均行MRI平扫及增强扫描。观察分析恶性黑色素瘤不同类型的MRI表现。结果发生在眼球的黑色素瘤均呈短T1、短T2表现,强化均匀;颅内恶性黑色素瘤的MRI表现具有多样性。结论恶性黑色素瘤除具有典型的黑色素瘤的MRI表现外,由于肿瘤细胞所含黑色素浓度及分布的不同,其MRI表现具有多样性,须鉴别,充分认识其各种表现,有助于提高诊断。     

Peculiarities of vasomotor reaction of cerebral vessels in arterial hypertension

We studied vasomotor activity of rat cerebral vessels. Peculiarities of endothelium-dependent reactions of cerebral arteries in induced arterial hypertension were revealed. Quantitative and qualitative relationships between the parameters of the vasomotor apparatus of cerebral arteries and parameters of circulatory homeostasis were determined. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 7, pp. 36–38, July, 2007