Publication Type. More Filters. Susceptibility-weighted imaging predicts infarct size and early-stage clinical prognosis in acute ischemic stroke. View 2 excerpts, cites results and background. Susceptibility-weighted imaging in post-treatment evaluation in the early stage in patients with acute ischemic stroke. Highly Influenced. View 3 excerpts, cites results and background.
View 2 excerpts, cites results. Susceptibility-diffusion mismatch in middle cerebral artery territory acute ischemic stroke: clinical and imaging implications. Mapping the ischemic penumbra and predicting stroke progression in acute ischemic stroke: the overlooked role of susceptibility weighted imaging. View 4 excerpts, cites methods and background. Factors associated with prominent vessel sign on susceptibility-weighted imaging in acute ischemic stroke.
View 2 excerpts, cites methods and background. S with 13 years of experience; B. Z with 7 years of experience together, and they were blinded to the clinical information to assess the baseline angiography data of the endovascular therapy patients. The differences between the core infarct areas and the at-risk areas, the core infarct areas and the other hypoperfusion areas, and the at-risk areas and the other hypoperfusion areas were analyzed by using paired t -tests.
All statistical analyses were conducted using commercially available software SPSS for Windows, version During the study period, patients underwent thrombectomy. Fifty-five patients were analyzed Table 1 ; among these patients, forty patients The artery occlusion in patients with new lesions was often located in the MCA-M1 Table 2 showed the comparison of the core infarct areas, the at-risk hypoperfusion areas, and the other hypoperfusion areas in patients with new lesions and without new lesions.
The MTT and TTP in the at-risk hypoperfusion areas with new lesions were significantly longer than in the hypoperfusion areas without new lesions In addition, we also compared the differences in PWI parameters between the core infarct areas, the at-risk hypoperfusion areas, and the other hypoperfusion areas in patients with new lesions Table 3. Acute stroke patients with new lesions showed longer MTT in the at-risk hypoperfusion areas Figure 4 showed the PWI images of acute stroke patients without new lesions.
Figure 5 showed the PWI images of acute stroke patients with new lesions. When the optimal cut-off value of MTT was 9. The results of the present study suggest that acute stroke patients had a high frequency of new lesions, and approximately It is interesting that patients with new lesions had longer MTTs and TTPs in the at-risk hypoperfusion areas than in the other hypoperfusion areas, and these differences were significant.
PWI may be useful in monitoring the perfusion status and in predicting the early new lesions of acute stroke patients after thrombectomy. Besides, Wouters et al. Yamada et al. In our study, MCA stenosis or occlusion was present in all acute stroke patients, so we selected the M2 segment of the ipsilateral MCA used for AIF to attain high sensitivity calculation techniques. In this study, the PWI parameters in the core infarct areas and the hypoperfusion areas were compared between patients with acute stroke who received thrombectomy.
These findings are in good agreement with those of a previous study 22 - The core infarct is irreversibly infarcted tissue, while the hypoperfusion areas around the core infarct areas are salvageable brain tissue, which may develop into infarcted tissue as new lesions or recover after timely treatment 25 - In our study, all patients within 6 h of the onset of ischemic symptoms were enrolled in order to prevent the heterogeneity caused by thrombectomy time.
Besides, the incidence of new lesions is higher than the other study 1 , the possible reason is that all patients in this study received thrombectomy. In addition, we found that patients with new lesions were more likely to have a history of diabetes mellitus than patients without new lesions.
Poor glycemic control leads to endothelial dysfunction, coagulative activation, and platelet hyperreactivity Patients with new lesions were significantly older than patients without new lesions. Some older patients may exhibit de novo lesions or incomplete clot dissolution due to various comorbidities and fragility as a result of their advanced age.
Vessel recanalization therapy possibly contributed to the occurrence of new lesions by incomplete clot dissolution and distal embolization 6 , 7 , or the new lesions may represent de novo lesions.
In our study, we found that the mTICI score was not significantly different between stroke patients with new lesions and those without new lesions after thrombectomy. In addition, the strengths of our study were that we found stroke patients with new lesions to have different hypoperfusion degrees between the new lesions namely, the at-risk hypoperfusion areas and the other hypoperfusion areas. The occurrence of new lesions within the hypoperfusion areas may be related to thromboembolic mechanisms Caplan et al.
Hypoperfusion enhances thrombus formation, promotes embolization of fresh thrombi and limits the ability of the blood stream to clear or wash out emboli 29 , To further explore which patients will develop new lesions, we compared the differences in PWI parameters between the at-risk hypoperfusion and other hypoperfusion areas. We found that the rCBF and rCBV had no significant differences between in the at-risk hypoperfusion areas and the other hypoperfusion areas, which was similar to a previous study Akazawa et al.
Total processing time was The MTT map produced with our software adequately estimated brain areas with perfusion deficit and was significantly less affected by random noise of the PWI when compared with the TTP map. Results of image. Clinical impacts of 3. The progress of the magnetic resonance MR imaging in the cerebral stroke patients was remarkable, and it became possible to evaluate a brain perfusion or function.
Here, we describe about the clinical application of the neuronal tracts and brain perfusion evaluation using 3. The subjects were patients with internal cerebral hemorrhage and major cerebral occlusive diseases.
Three dimensional anisotropy contrast 3DAC imaging and diffusion tensor imaging DTI were accepted to estimate the damages of neurnal tracts. Perfusion weighted images with the contrast medium were performed for a quantitative evaluation.
The pyramidal tracts were depicted well with 3DAC imaging. Fractional anisotropy FA value generated from DTI can predict the outcome of the motor dysfunction in each patient at early stage. Cerebral blood volume calculated from perfusion weighted imaging PWI was correlated with and cerebral vascular reserve capacity.
Background Arterial spin labeling ASL perfusion-weighted imaging PWI by magnetic resonance imaging MRI has been shown to be useful for identifying asphyxiated newborns at risk of developing brain injury, whether or not therapeutic hypothermia was administered.
However, this technique has been only rarely used in newborns until now, because of the challenges to obtain sufficient signal-to-noise ratio SNR and spatial resolution in newborns. Each of the enrolled newborns was scanned at least once during the first month of life. Control and labeled images were registered separately to reduce the effect of motion artifacts. For each scan, the axial slice at the level of the basal ganglia was used for comparisons.
Each scan was scored for its image quality. Quantification of whole-slice cerebral blood flow CBF was done afterwards using previously described formulas. Results A total number of 61 concomitant PASL and pCASL scans were obtained in nineteen asphyxiated newborns treated with therapeutic hypothermia and four healthy newborns.
Materials and methods: Fifty-five patients with symptomatic hyperacute first 6 h or acute 7—24 h ischaemic stroke underwent diffusion and perfusion evaluation. The best performance corresponded to TTP, which showed a sensitivity of 0. This contribution considers the possibilities involved with using functional methods in magnetic resonance imaging MRI diagnostics for brain tumors. In cases of brain tumor, PWI aids in grading and better differentiation in diagnostics as well as for pre-therapeutic planning.
In addition, the course of treatment, both after chemo- as well as radiotherapy in combination with surgical treatment, can be optimized. PWI allows better estimates of biological activity and aggressiveness in low grade brain tumors, and in the case of WHO grade II astrocytoma showing anaplastically transformed tumor areas, allows more rapid visualization and a better prediction of the course of the disease than conventional MRI diagnostics.
Diffusion MRI, due to the directional dependence of the diffusion, can illustrate the course and direction of the nerve fibers, as well as reconstructing the nerve tracts in the cerebrum, pons and cerebellum 3-dimensionally. Diffusion imaging can be used for describing brain tumors, for evaluating contralateral involvement and the course of the nerve fibers near the tumor.
Due to its operator dependence, DTI based fiber tracking for defining risk structures is controversial. DWI can also not differentiate accurately between cystic and necrotic brain tumors, or between metastases and brain abscesses.
H-MRS provides information on cell membrane metabolism, neuronal integrity and the function of neuronal structures, energy metabolism and the formation of tumors and brain tissue necroses. Diagnostic problems such as the differentiation between neoplastic and non-neoplastic lesions, grading cerebral glioma and distinguishing between primary brain tumors and metastases can be resolved. An additional contribution will discuss the control of the course of glial tumors after radiotherapy.
The role of dynamic susceptibility contrast-enhanced perfusion MR imaging in differentiating between infectious and neoplastic focal brain lesions: results from a cohort of consecutive patients.
Brain perfusion-weighted MRI PWI may be employed as a complementary non-invasive tool, providing relevant data on hemodynamic parameters, such as the degree of angiogenesis of lesions. We aimed to employ dynamic susceptibility contrast-enhanced perfusion MR imaging DSC-MRI to differentiate between infectious and neoplastic brain lesions by investigating brain microcirculation changes. MRI examinations were performed using a 1. A preload of paramagnetic contrast agent gadolinium was administered 30 seconds before acquisition of dynamic images , followed by a standard dose 10 seconds after starting imaging acquisitions.
The relative cerebral blood volume rCBV values were determined by calculating the regional cerebral blood volume in the solid areas of lesions, normalized to that of the contralateral normal-appearing white matter. Discriminant analyses were performed to determine the cutoff point of rCBV values that would allow the differentiation of neoplastic from infectious lesions and to assess the corresponding diagnostic performance of rCBV when using this cutoff value.
Among them, 12 cases had perfusion imaging simultaneously. DWI and ADC-map are highly valuable in the early diagnosis and monitoring the development of brain ischemic disease. Magnetic resonance perfusion imaging without contrast media. Principles of magnetic resonance imaging techniques providing perfusion -related contrast weighting without administration of contrast media are reported and analysed systematically.
Especially common approaches to arterial spin labelling ASL perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue.
After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery FAIR ASL perfusion preparation approach followed by true fast imaging with steady precession true FISP data recording was developed and implemented on whole-body scanners operating at 0.
ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates as also present in many tumours.
Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. Purpose To evaluate the feasibility of directly imaging perfusion of human brain tissue by using magnetic resonance MR imaging with inhaled hyperpolarized xenon Xe.
Materials and Methods In vivo imaging with Xe was performed in three healthy participants. The combination of a high-yield spin-exchange optical pumping Xe polarizer, custom-built radiofrequency coils, and an optimized gradient-echo MR imaging protocol was used to achieve signal sensitivity sufficient to directly image hyperpolarized Xe dissolved in the human brain.
Conventional T1- weighted proton hydrogen 1 [ 1 H] images and perfusion images by using arterial spin labeling were obtained for comparison. Conclusion Hyperpolarized Xe MR imaging is an injection-free means of imaging the perfusion of cerebral tissue. The proposed method images the uptake of inhaled xenon gas to the extravascular brain tissue compartment across the intact blood-brain barrier.
This level of sensitivity is not readily available with contemporary MR imaging methods. Purpose : To evaluate the feasibility of a simplified method based on diffusion- weighted imaging DWI acquired with three b -values to measure tissue perfusion linked to microcirculation, to validate it against from perfusion -related parameters derived from intravoxel incoherent motion IVIM and dynamic contrast-enhanced DCE magnetic resonance MR imaging , and to investigate its utility to differentiate low- from high-grade gliomas.
Materials and Methods : The prospective study was approved by the local institutional review board and written informed consent was obtained from all patients. Correlation between perfusion -related parameters was analyzed by using the Spearman rank correlation. The diagnostic performance for tumor grading was evaluated with receiver operating characteristic ROC analysis.
SPF may serve as a valuable alternative to measure tumor perfusion in gliomas in a noninvasive, convenient and efficient way. The institutional animal care and use committee approved this study. Leptomeningeal collateralization in acute ischemic stroke: Impact on prominent cortical veins in susceptibility- weighted imaging.
Verma, Rajeev K. Background: The extent of hypoperfusion is an important prognostic factor in acute ischemic stroke. Previous studies have postulated that the extent of prominent cortical veins PCV on susceptibility- weighted imaging SWI reflects the extent of hypoperfusion. Our aim was to investigate, whether there is an association between PCV and the grade of leptomeningeal arterial collateralization in acute ischemic stroke. Methods: 33 patients with acute ischemic stroke due to a thromboembolic M1-segment occlusion underwent MRI followed by digital subtraction angiography DSA and were subdivided into two groups with very good to good and moderate to no leptomeningeal collaterals according to the DSA.
Results: 20 patients showed very good to good and 13 patients poor to no collateralization. An evaluation of morphological and functional multi-parametric MRI sequences in classifying non-muscle and muscle invasive bladder cancer. Patients underwent mpMRI before tumour resection. Four MRI sets, i. Accuracy was determined using histopathology as the reference standard. A total of 82 tumours were analysed. PWI , DWI and DTI quantitative parameters were shown to be significantly different in cancerous versus non-cancerous areas within the bladder wall in T2-labelled lesions.
If our data are validated, then mpMRI could precede cystoscopic resection to allow a faster recognition of MIBC and accelerated treatment pathways.
Rome Italy. United Kingdom. Aademic Urology Unit. The visual identification of PWI -DWI-mismatch tissue depends strongly on the observer, prompting a need for software, which estimates potentially Method: The algorithm initially identifies PWI lesions Four expert raters Functional response of tumor vasculature in rats' glioma to hypercarbia evaluated by MR perfusion weighted imaging.
Objective: To evaluate the feasibility of MR PWI in judging maturity and variability of tumor vasculature in gliomas in rats. Methods: Twenty male SD rats were randomly assigned to tumor group and control group. PaCO 2 and blood pH values of rats were monitored. Relative cerebral blood volume rCBV and relative cerebral blood flow rCBF values of tumors and normal brain tissue were measured. Brain sample were examined histologically using HE and immunohistochemical staining for smooth muscle actin SMA.
The histological features of gliomas were observed and SMA positively stained vessels of each tumor were counted manually using a light microscope. Results: PaCO 2 increased significantly [from 4. It may be a useful technique to measure maturity of tumor vessels.
MRI in acute subarachnoid haemorrhage; findings with a standardised stroke protocol. There is doubt as to whether acute haemorrhage is visible on MRI. We carried out MRI within 6 h of symptom onset on five patients with minor low Hunt and Hess grades 1 or 2 subarachnoid haemorrhage SAH diagnosed by CT to search for any specific pattern. Perfusion maps were normal in all cases. MRA and conventional angiography revealed an aneurysm in only one patient.
Full Text Available Purpose: To evaluate the feasibility of a simplified method based on diffusion- weighted imaging DWI acquired with three b-values to measure tissue perfusion linked to microcirculation, to validate it against from perfusion -related parameters derived from intravoxel incoherent motion IVIM and dynamic contrast-enhanced DCE magnetic resonance MR imaging , and to investigate its utility to differentiate low- from high-grade gliomas.
Materials and Methods: The prospective study was approved by the local institutional review board and written informed consent was obtained from all patients. Perfusion imaging PI demonstrated increased perfusion and diffusion- weighted imaging DWI showed high signal limited to the left temporoparietal cortex in a year-old man with nonconvulsive status epilepticus. The EEG showed a slow delta-wave focus. Reversible changes in echo planar perfusion - and diffusion- weighted MRI in status epilepticus.
Investigation of contrast agent dosage for perfusion-weighted MRI. Material and methods: In a prospective study bolus injection of gadolinium-DTPA was performed at dosages of 0. Conclusion: For meaningful MR perfusion imaging at 1.
Perfusion and spectroscopy magnetic resonance imaging in a case of lymphocytic vasculitis mimicking brain tumor. Lymphocytic vasculitis of the central nervous system is an uncommon subtype of primary angiitis of the central nervous system PACNS — a rare inflammatory disorder affecting parenchymal and leptomeningeal arteries and veins. Establishing diagnosis on the basis of neuroimaging only is difficult, as it can mimic a brain tumor.
Thus, histological diagnosis is essential for appropriate management. We present a case of biopsy-proven lymphocytic vasculitis mimicking a brain tumor on neuroimaging that was subsequently successfully treated with steroid therapy. Regional hypoperfusion on PWI and elevation of glutamate and glutamine levels on MRS without associated typical tumor spectra are common findings in inflammatory disorders, including PACNS, and can be useful in differential diagnosis with tumors.
Recent advances in magnetic resonance imaging for stroke diagnosis. Full Text Available In stroke, diagnosis and identification of the infarct core and the penumbra is integral to therapeutic determination. With advances in magnetic resonance imaging MRI technology, stroke visualization has been radically altered. MRI allows for better visualization of factors such as cerebral microbleeds CMBs, lesion and penumbra size and location, and thrombus identification; these factors help determine which treatments, ranging from tissue plasminogen activator tPA, anti-platelet therapy, or even surgery, are appropriate.
However, to better clarify the neurological environment, susceptibility- weighted imaging SWI for assessing oxygen saturation and the presence of CMBs as well as additional modalities, such as amide proton transfer APT imaging for pH mapping, have emerged to offer more insight into anatomical and biological conditions during stroke. Further research has unveiled potential for alternative contrasts to gadolinium for PWI as well, as the contrast has contraindications for patients with renal disease.
Superparamagnetic iron oxide nanoparticles SPIONs as an exogenous contrast and arterial spin labeling ASL as an endogenous contrast offer innovative alternatives. Thus, emerging MRI modalities are enhancing the diagnostic capabilities of MRI in stroke and provide more guidance for patient outcome by offering increased accessibility, accuracy, and information.
Magnetic resonance myocardial perfusion imaging -First experience at 3. Klumpp, B. Objective: MR myocardial perfusion imaging MRMPI is an established technique for the evaluation of the hemodynamical relevance of coronary artery disease.
Perfusion imaging at 3. Aim of this study was to evaluate myocardial MR perfusion imaging at 3. Materials and methods: Twelve patients with stable Angina pectoris and known or suspected coronary artery disease were examined at 3. Myocardial perfusion was assessed using a saturation recovery gradient echo 2D sequence TR 1. Perfusion series were assessed by two independent observers. Reference for the presence of relevant coronary artery stenoses was invasive coronary angiography.
Two experienced observers evaluated the coronary angiograms in biplane projections for the presence and grade of stenoses. Results were compared with the MR perfusion analysis. Results: All MR examinations could be safely performed and yielded high image quality. In four patients myocardial hypoperfusion was ruled out stenosis perfusion reserve index was significantly reduced in hypoperfused myocardium with 1. Alterations in diffusion and perfusion in the pathogenesis of peritumoral brain edema in meningiomas.
Bitzer, M. Magnetic resonance perfusion and diffusion studies were undertaken to clarify the significance of ischemia in the pathogenesis of peritumoral brain edema in patients with meningiomas. Included in this study were 26 patients with 27 meningiomas and 5 gliomas. Perfusion-weighted imaging PWI was performed using a gradient-echo, echo-planar- imaging EPI sequence for calculation of the relative regional cerebral blood volume rrCBV and the relative regional cerebral blood flow index rrCBFi.
Furthermore, multi-slice spin-echo EPI sequences were applied in order to obtain anisotropic and isotropic diffusion- weighted imaging DWI. Apparent diffusion coefficient ADC values were then calculated for peritumoral brain parenchyma from tumors, with and without edema, using various diffusion sensitivities. Meningiomas without edema demonstrated a minimal increase of perfusion parameters in the peritumoral brain tissue.
In contrast, cases with brain edema had highly significant p 2. Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light.
A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software.
A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.
The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation.
The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. Quantitative perfusion imaging in magnetic resonance imaging.
Zoellner, F. Magnetic resonance imaging MRI is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation.
Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible.
One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium Gd , as a tracer for calculating hemodynamic parameters.
Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels.
Such efforts are being promoted by the respective professional bodies. Combined value of susceptibility weighted imaging and dynamic susceptibility- weighted contrast-enhanced MR perfusion-weighted imaging in brain astrocytoma grading.
Objective: To assess the value of combination of susceptibility weighted imaging SWI and dynamic susceptibility- weighted contrast-enhanced DSC perfusion-weighted magnetic resonance imaging in astrocytoma grading. The intratumoral susceptibility signal intensity ITSS and relative cerebral blood volume rCBV max were used to determine the grade of astrocytomas by Kruskal Wallis test, Welch test, Spearman correlation coefficients, Pearson correlation coefficients, and receiver operating characteristic curve ROC statistic methods.
Intravoxel incoherent motion IVIM imaging is an MRI perfusion technique that uses a diffusion- weighted sequence with multiple b values and a bi-compartmental signal model to measure the so-called pseudo-diffusion of blood caused by its passage through the microvascular network. The goal of the current study was to assess the feasibility of IVIM perfusion fraction imaging in patients with acute stroke.
Images were collected in 17 patients with acute stroke. Image quality was assessed by two radiologists, and quantitative analysis was performed in regions of interest placed in the stroke area, defined by thresholding the apparent diffusion coefficient maps, as well as in the contralateral region. IVIM perfusion fraction maps showed an area of decreased perfusion fraction f in the region of decreased apparent diffusion coefficient.
Quantitative analysis showed a statistically significant decrease in both IVIM perfusion fraction f 0. IVIM perfusion fraction imaging is feasible in acute stroke. IVIM perfusion fraction is significantly reduced in the visible infarct. Further studies should evaluate the potential for IVIM to predict clinical outcome and treatment response. Computed tomography perfusion imaging denoising using Gaussian process regression.
Brain perfusion weighted images acquired using dynamic contrast studies have an important clinical role in acute stroke diagnosis and treatment decisions. However, computed tomography CT images suffer from low contrast-to-noise ratios CNR as a consequence of the limitation of the exposure to radiation of the patient.
As a consequence, the developments of methods for improving the CNR are valuable. The majority of existing approaches for denoising CT images are optimized for 3D spatial information, including spatial decimation spatially weighted mean filters and techniques based on wavelet and curvelet transforms. However, perfusion imaging data is 4D as it also contains temporal information. Our approach using Gaussian process regression GPR , which takes advantage of the temporal information, to reduce the noise level.
At the level of individual voxel, GPR provides a stable baseline, helps us to identify key parameters from tissue time-concentration curves and reduces the oscillations in the curve.
GPR is superior to the comparable techniques used in this study. Usefulness of perfusion MR imaging in hyperacute ischemic stroke. Perfusion MR imaging is a new technique for the assessment of acute ischemic stroke. The aim of this study was to evaluate the usefulness of this imaging in hyperacute ischemic stroke in comparison with conventional CT and MR imaging.
Eight patients presenting the symptoms of acute ischemic stroke due to middle cerebral artery occlusion were included in this study.
Cerebral blood volume CBV maps were then obtained from dynamic MR imaging data by using numerical integration techniques.
The findings of CBV maps were obviously abnormal in all patients, as compared with normal or focal subtle abnormal findings seen on initial CT and MR images. CBV in the occluded arterial territory was lower in all eight patients;two had focal regions of increased CBV within the affected territory, indicating reperfusion hyperemia.
In all patients, regions of abnormal CBV were eventually converted to infarctions on follow-up images. Perfusion MR imaging was useful for the evaluation of hemodynamic change occurring during cerebral perfusion in hyperacute ischemic stroke, and prediction of the final extent of infarction. These results suggest that pertusion MR imaging can play an important role in the diagnosis and management of hyperacute ischemic stroke. Perfusion MRI derived indices of microvascular shunting and flow control correlate with tumor grade and outcome in patients with cerebral glioma.
Objectives: Deficient microvascular blood flow control is thought to cause tumor hypoxia and increase resistance to therapy. In glioma patients, we tested whether perfusion-weighted MRI PWI based indices of microvascular flow control provide more information on tumor grade and patient outcome Material and Methods: Seventy-two glioma patients sixty high-grade, twelve low-grade gliomas were included.
The ability of these parameters and CBV to differentiate tumor grade were assessed by receiver operating characteristic curves and logistic regression. Their ability to predict time to progression and overall survival Over the past few decades, magnetic resonance imaging has been utilized as a powerful imaging modality to evaluate the structure and function of various organs in the human body,such as the brain.
Additionally, diffusion and perfusion MR imaging have been increasingly used in neurovascular clinical applications. In diffusion- weighted magnetic resonance imaging , the mobility of water molecules is explored in order to obtain information about the microscopic behavior of the tissues. In contrast C-arm flat detector computed tomography parenchymal blood volume imaging : the nature of parenchymal blood volume parameter and the feasibility of parenchymal blood volume imaging in aneurysmal subarachnoid haemorrhage patients.
Kamran, Mudassar; Byrne, James V. C-arm flat detector computed tomography FDCT parenchymal blood volume PBV measurements allow assessment of cerebral haemodynamics in the neurointerventional suite.
PBV is a composite perfusion parameter incorporating both blood flow and blood volume weightings. Injection of thrombin into the middle cerebral artery MCA of mice has been proposed as a new model of thromboembolic stroke. Spontaneous reperfusion thus contributed to the variability in ischemic volume in this model.
The study confirmed the value of the model for evaluating new thrombolytic treatments, but calls for extended MRI follow-up at the acute stage in therapeutic studies. Diffusion and perfusion imaging of bone marrow. In diffusion- weighted magnetic resonance imaging DWI , the observed MRI signal intensity is attenuated by the self-diffusion of water molecules.
DWI provides information about the microscopic structure and organization of a biological tissue, since the extent and orientation of molecular motion is influenced by these tissue properties. In recent years, both techniques have been applied successfully in healthy bone marrow as well as for the characterization of bone marrow alterations or lesions; e.
In this review article, firstly a short introduction to diffusion- weighted and dynamic contrast-enhanced MRI is given. Afterwards a detailed overview of the results of both techniques in healthy bone marrow and their applications for the diagnosis of various bone-marrow pathologies, like osteoporosis, bone tumors, and vertebral compression fractures are described.
Next, the animal was imaged in a 1. Full Text Available Tumoral neoangiogenesis characterizes high grade gliomas. The aim of the study was to characterize putative tumoral neoangiogenesis via the study of maximal rCBV with a Region of Interest ROI approach in three tumor areas—the contrast-enhancing area, the nonenhancing tumor, and the high perfusion area on CBV map—in patients affected by contrast-enhancing glioma grades III and IV.
Maximal rCBV values for each patient were averaged according to glioma grade. In conclusion, neoangiogenesis encompasses different tumor compartments and CBV maps appear capable of best characterizing the degree of neovascularization. Facing contrast-enhancing brain tumors, areas of high perfusion on CBV maps should be considered as the reference areas to be targeted for glioma grading. Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging.
The aim of this work was to assess magnetic resonance MR perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography CT imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns.
Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically.
Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion , MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type.
CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T weighted MRI at 3T.
Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T weighted fast The input function was obtained from the internal carotid artery.
An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values
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