Perfusion MRI

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Lung perfusion: MRI vs. SPECT for screening in suspected chronic thromboembolic pulmonary hypertension.

Lung perfusion: MRI vs. SPECT for screening in suspected chronic thromboembolic pulmonary hypertension.

DCE perfusion images were analyzed on a slice-by-slice basis by subtraction of the baseline precontrast image; this was performed on a GE Advantage workstation. The peak enhancement image in the contrast passage time series was independently analyzed by a general radiologist (C.S.J., 5 years of experience) and a consultant chest radiologist (A.J.S., 11 years of experience) blinded to all oth- er imaging and clinical information. The images were reviewed on a general reporting workstation in the general radiology depart- ment on diagnostic quality Barco screens (Barco, UK). The images were qualitatively assessed as either positive or negative for chronic thromboembolic disease. On both DCE perfusion MRI and perfu- sion SPECT, the presence of one or more segmental or subsegmen- tal perfusion defects was considered positive for pulmonary embolic disease, as per recognized clinical guidelines. 14 Figure 1 gives an example of a normal and positive SPECT and DCE-MRI scan. The DCE perfusion images were typically viewed with a win- dow of 40 and a level of 19, although this was manipulated if required. Subsequently, the SPECT imaging was reviewed by the same radiologists, at a separate sitting, separated from the time of the MRI analysis by at least 1 week, blinded to all other imaging and clinical information. Any disagreements were resolved by con- sensus. The multidisciplinary decision of the presence or absence
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Evidence-based guideline: The role of diffusion and perfusion MRI for the diagnosis of acute ischemic strokeReport of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

Evidence-based guideline: The role of diffusion and perfusion MRI for the diagnosis of acute ischemic strokeReport of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

, 2008), and Caplan’s Stroke: A Clinical Approach, 4th ed. (Elsevier, 2009). Dr. Detre serves on a scientific advisory board of Pittsburgh NMR Center; serves as an Associate Editor of the Journal of Neuroimaging; serves as a consultant for Pfizer Inc; receives research support from Wyeth, AstraZeneca, Pfizer Inc, the National Science Foundation and from the NIH (R01 MH080729 [PWI], K24 NS058386 [PWI],P30 NS045839 [PWI], T32 NS054575 [PWI], R01 NS060653 [Co-I], R01 NS061572 [Co-I], P41 RR002305 [PWI], R24 HD050836 [PWI], R24 HD050838 [Co-I], R01 NS057400 [Co-I], R01 DK085615 [Co-I], R01AG034682 [Co-I], R21 DA025882 [Co-I], R01 HL102119 [Co-I], R03 DA027098 [Co-I], R24 HD050836 [Co-I]); is an inventor on a patent re: ASC Perfusion MRI and receives royalties from the University of Pennsylvania for its licensure; and has acted as a witness or consultant in legal proceedings. Dr. Edelman serves as an Associate Editor for Investigative Radiology; has received re- search support from Siemens Healthcare; and holds a provisional patent re: non-contrast MR angiography and receives license fee payments from Siemens Healthcare. Dr. Jaigobin has received speaker honoraria from sanofi-aventis and Boehringer Ingelheim. Dr. Kidwell serves on the edito- rial boards of Neurocritical Care Journal, the Journal of Neuroimaging, and Stroke Research and Treatment; has served as a consultant for Embrella Cardiovascular, Inc.; and receives research support from Baxter Interna- tional Inc., and the NIH (NINDS P50 NS044378 [Co-I] and NINDS U54 NS057405 [PWI]). Dr. Mohr serves on scientific advisory boards for Mitsubishi Tanabe Pharma Corporation and Schering-Plough Corp.; serves on the editorial board of Cerebrovascular Diseases and as Chief Edi- tor of Stroke; receives royalties from the publication of Stroke: Pathophysi- ology, Diagnosis, and Management 4th ed. (Churchill Livingstone, 2004); serves as a consultant for Schering-Plough Corp.; and has given expert testimony on PFO and unruptured aneurysms. Dr. Sloan serves on the editorial boards of the Journal of Neuroimaging, Stroke, and the Journal of Stroke and Cerebrovascular Diseases; holds financial interest in Boehringer Ingelheim, PDL BioPharma, Inc., Terumo Neurovascular Monitoring, NCME, and Bayer Schering Pharma; has received research support from ImaRx Therapeutics, Inc., Guidant, Cordis, Bard Peripheral Vascular, Inc., Abbott, Boston Scientific, and the NIH/NINDS; estimates that ⬍ 10% of his clinical effort is spent on transcranial Doppler; and has given expert testimony in a legal proceeding related to this manuscript. Dr. Sorensen serves on scientific advisory boards for Olea Medical, Sie- mens Healthcare, Genentech, Inc., Lantheus Medical Imaging, Mitsub- ishi Tanabe Pharma Corporation, Takeda Pharmaceutical Company Limited/Millennium Pharmaceuticals, Inc., AstraZeneca, the NIH, and Bayer Schering Pharma; has received funding for travel from the NIH,
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Quantitative histopathologic assessment of perfusion MRI as a marker of glioblastoma cell infiltration in and beyond the peritumoral edema region

Quantitative histopathologic assessment of perfusion MRI as a marker of glioblastoma cell infiltration in and beyond the peritumoral edema region

27 between human gliomas and the G7 model in which tumors grow in the brains of immunodeficient mice. We contend that immune status is unlikely to have a significant effect on the analysis of the relation between local perfusion and tumor burden proposed here. In fact, the tumor-related perfusion drop was related to infiltration through the biomechanical effect of vascular co-option and/or edema, which are clinically relevant mechanisms. To minimize intracranial pressure and vascular compression effects, tumor size was generally limited to less than 10% of total brain volume. This also increased the relevance of evaluation tests requiring significant difference between tumor volume and brain volume(27). Finally, there are MRI specificities in this work that should be emphasized. The combination of a 7T instrument with a novel perfusion sequence allowed us to overcome SNR limitations of clinical perfusion imaging based on ASL sequences, enabling the study of low perfusion regions. This advantage was counterbalanced by the need to use much higher resolution than in a clinical context in order to properly resolve the perfusion distribution within the mouse brain. Hence, it is important to recognize that alternative perfusion MRI techniques (e.g. DSC) could be more efficient in probing infiltration in a clinical context.
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Estimation of Mean Radius, Length and Density of Microvasculature Using Diffusion and Perfusion MRI

Estimation of Mean Radius, Length and Density of Microvasculature Using Diffusion and Perfusion MRI

In theory, diusion and perfusion information in MRI maps can be combined to yield morphological information, such as capillary density, volume and possibly capillary plasma velocity. This paper suggests a new method for determination of mean radius, length and capillary density in normal regions using diusion and perfusion MRI. Mean Transit Time (MTT), Cerebral Blood Volume (CBV), Apparent Diusion Coecient (ADC), pseudo-diusion coecient ( D

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Texture Feature Ratios from Relative CBV Maps of Perfusion MRI Are Associated with Patient Survival in Glioblastoma

Texture Feature Ratios from Relative CBV Maps of Perfusion MRI Are Associated with Patient Survival in Glioblastoma

MATERIALS AND METHODS: MR perfusion data of 24 patients with glioblastoma from The Cancer Genome Atlas were analyzed in this study. One- and 2D texture feature ratios and kinetic textural features based on relative CBV values in the contrast-enhancing and nonenhancing lesions of the tumor were obtained. Receiver operating characteristic, Kaplan-Meier, and multivariate Cox proportional hazards regression analyses were used to assess the relationship between texture feature ratios and overall survival.

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Discrimination between Glioma Grades II and III Using Dynamic Susceptibility Perfusion MRI: A Meta Analysis

Discrimination between Glioma Grades II and III Using Dynamic Susceptibility Perfusion MRI: A Meta Analysis

When evaluating the diagnostic ac- curacy of DSC in this meta-analysis, we used exploratory evaluations of optimal cutoffs for discrimination between gli- oma grades II and III. This lack of eval- uating diagnostic accuracy from a prespecified cutoff can increase the diagnostic potential presented in the meta-analysis. A limita- tion in DSC perfusion MR imaging is the nonlinear relationship between gadolinium concentration and the relaxivity-time curve, and nonexponential relaxation decay. 42 Consequently, measured

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Introducing a New Definition Towards Clinical Detection of Microvascular Changes Using Diffusion and Perfusion MRI

Introducing a New Definition Towards Clinical Detection of Microvascular Changes Using Diffusion and Perfusion MRI

Blood perfusion of tissue assures the delivery of oxygen and nutrients to cells. To achieve this goal, fresh, oxygenated \arterial" blood is delivered to the tissue through the capillary network, which is opti- mized for blood-tissue exchange. Oxygen and nutrients are transported, passively or actively, in the tissue through the capillary wall. Tissue metabolism results in waste products that are eliminated through the capillary network to constitute deoxygenated \venous" blood. This process depends on many parameters, such as blood pressure and velocity, capillary network den- sity and geometry, capillary wall permeability, nutrient or oxygen diusion and extraction rates, which can be grouped in three categories: Micro-vascular anatomy and histology, blood microcirculation and blood-tissue exchanges.
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Added Value of Spectroscopy to Perfusion MRI in the Differential Diagnostic Performance of Common Malignant Brain Tumors

Added Value of Spectroscopy to Perfusion MRI in the Differential Diagnostic Performance of Common Malignant Brain Tumors

PWI. Dynamic-susceptibility perfusion contrast-enhanced T2*- weighted gradient-echo echo-planar images (TR/TE ⫽ 1980/30 ms, 4.0-mm thick sections, 0.8-mm gap, FOV ⫽ 220 mm, ma- trix ⫽ 128 ⫻ 128, flip angle ⫽ 90°, phases ⫽ 75) were acquired during the first pass of a standard-dose (0.1 mmol/Kg) bolus of gadoteric acid at 0.5 mmol/mL. Contrast material was injected at a rate of 6 mL/s for all patients, with a 10-second delay. From 7 to 12 sections were selected on T2 FLAIR-weighted images, depend- ing on the volume of the tumor.

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Comparison of methods for quantitative analysis of dynamic
susceptibility contrast enhanced brain perfusion MRI

Comparison of methods for quantitative analysis of dynamic susceptibility contrast enhanced brain perfusion MRI

Quantitative perfusion measurements may be derived by different postpro- cessing methods [18]. Most methods demand for user-selected parameters which may lead to variation in quantitative perfusion values. Therefore there are (semi-)automatic methods as well. This chapter provides informa- tion about several postprocessing methods which are commonly used. First the theory behind the calculations is explained in section 2.1. In section 2.2 the different approaches to determine the arterial input function (AIF) are mentioned. Section 2.3 gives information about the commonly used decon- volution methods such as singular value decomposition. Section 2.4 provides four methods to integrate the tracer concentration-time curve to calculate CBV. This chapter concludes with a section about the assumptions used during the quantification of perfusion data.
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Arterial Spin Labeling Perfusion MRI Stratifies Progression Free Survival and Correlates with Epidermal Growth Factor Receptor Status in Glioblastoma

Arterial Spin Labeling Perfusion MRI Stratifies Progression Free Survival and Correlates with Epidermal Growth Factor Receptor Status in Glioblastoma

ASL CBF maps of patients with GBM (n ⫽ 53) were visually eval- uated by 3 board-certified neuroradiologists blinded to patient history for focal perfusion abnormality (hyper- or hypoperfu- sion) in the tumor tissue. Two perfusion patterns were character- ized on the basis of qualitative evaluation by the readers: Pattern 1 was characterized by the presence of substantial and easily iden- tifiable hyperperfused tumor tissue in the CBF map, which often had a “ring-of-fire” appearance (Fig 1A–C); in comparison, pat- tern 2 corresponded to the absence of such easily identifiable hy- perperfused tumor tissue and thus appeared in the CBF map as areas of lower perfusion in the region infiltrated by GBM (Fig 1D–F). The ␬ agreement test showed that evaluation of the per-
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Diffusion and Perfusion MRI to Differentiate Treatment Related Changes Including Pseudoprogression from Recurrent Tumors in High Grade Gliomas with Histopathologic Evidence

Diffusion and Perfusion MRI to Differentiate Treatment Related Changes Including Pseudoprogression from Recurrent Tumors in High Grade Gliomas with Histopathologic Evidence

consisted of 68 consecutive patients with HGG according to the following inclu- sion criteria: 1) diagnosis of primary gli- oblastoma or anaplastic astrocytoma, 2) treatment with RT and temozolomide (Temodar), 3) new and/or increasing enhancing mass lesions at follow-up MR imaging suspicious for treatment-re- lated changes versus recurrent tumor, and 4) brain MR imaging, including contrast T1-weighted imaging with DWI and/or DSC perfusion, ⱕ 35 days before subsequent resection of the en- hancing mass lesion.

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Contrast Leakage Patterns from Dynamic Susceptibility Contrast Perfusion MRI in the Grading of Primary Pediatric Brain Tumors

Contrast Leakage Patterns from Dynamic Susceptibility Contrast Perfusion MRI in the Grading of Primary Pediatric Brain Tumors

Dynamic susceptibility contrast perfusion MR imaging has demonstrated utility in the pretreatment evaluation of adult in- tracranial neoplasms for tumor grading, guiding biopsy, and prognosis. However, while the most common adult primary pa- renchymal neoplasms are of the astrocytic cell type, the most common pediatric primary brain tumors have diverse cellular origins, with astrocytic origin for pilocytic astrocytomas and em- bryonal neuroepithelial origin for medulloblastomas. Even within astrocytomas, outside of the classic “cyst and mural nodule” appearance of pilocytic astrocytomas, there is some overlap in the radiographic and histologic appearance of pilo- cytic astrocytomas and high-grade gliomas, with relative cere- bral volume (rCBV) demonstrating usefulness in distinguish-
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Evaluation of Encephaloduroarteriosynangiosis Efficacy Using Probabilistic Independent Component Analysis Applied to Dynamic Susceptibility Contrast Perfusion MRI

Evaluation of Encephaloduroarteriosynangiosis Efficacy Using Probabilistic Independent Component Analysis Applied to Dynamic Susceptibility Contrast Perfusion MRI

was to apply ICA to DSC-MR imaging data to evaluate hemody- namic changes after EDAS, to assess whether this method can detect changes consistent with structural imaging measures, and to compare the results with classic perfusion measures—that is, by quantitatively separating the DSC-MR imaging time-series data in each image voxel into independent temporal patterns con- sistent with arterial, capillary, and venous hemodynamics, we hy- pothesized that probabilistic ICA would detect subtle changes in vascularity that may not be captured by classic perfusion mea- sures. We further hypothesized that brain regions in adults with symptomatic ICAS or MMD would contain tissue with a high venous probability, suggesting hemodynamics consistent with delayed venous flow. Additionally, we posited that a favorable increase in tissue perfusion within the surgical hemisphere after EDAS would reduce this venous probability and that this reduc-
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What Have We Learned from Perfusion MRI in Multiple Sclerosis?

What Have We Learned from Perfusion MRI in Multiple Sclerosis?

have not been accounted for in any MS perfusion study. Further- more, although technical factors can alter the comparison among subjects, analysis of lesion perfusion has been performed using NAWM as a comparator, which is known to be abnormal in MS. There is also an issue with using any area of the brain to nor- malize perfusion maps. Indeed, CBF maps obtained after decon- volution are dependent on the arterial input function, which is influenced by contrast agent properties, partial volume effects, and bolus delay and dispersion. 48 A way to reduce the contribu-

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Impact of Software Modeling on the Accuracy of Perfusion MRI in Glioma

Impact of Software Modeling on the Accuracy of Perfusion MRI in Glioma

Relative cerebral blood volume values to differentiate high-grade glioma recurrence from posttreatment radiation effect: direct correlation between image-guided tissue histopathology and[r]

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Automatic Characterization of Myocardial Perfusion in Contrast Enhanced MRI

Automatic Characterization of Myocardial Perfusion in Contrast Enhanced MRI

The main limitation of our approach is the 2D nature of the image registration that does not allow correcting the mis- alignment component along the normal to the acquisition plane (i.e., z-axis). The proposed algorithm can be extended in 3D without main modification, but some problems should be solved. The first one is the low image resolution along the z-axis that implies the production of interpolation artefacts. The second one is the increasing in the algorithm complexity, because the optimization algorithm has to work on 6 instead of 3 parameters. Finally, slices related to a 3D volume are ac- quired in di ff erent times, as previously shown, so they are not homogeneous with respect to the intensity of the CM. In our opinion, the use of 3D analysis of myocardial perfusion MRI in clinical environment requires both an improvement in MR device technology (i.e., better resolution in z-axis direction) and in computer power (i.e., reduction of processing time).
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The role of perfusion and diffusion MRI in the assessment of patients affected by probable idiopathic normal pressure hydrocephalus. A cohort-prospective preliminary study

The role of perfusion and diffusion MRI in the assessment of patients affected by probable idiopathic normal pressure hydrocephalus. A cohort-prospective preliminary study

Given the different perfusion patterns between PP and NP, we suggest that perfusion MRI could be use- ful together with invasive tests in selecting patients for surgical treatment. As an example, three PP patients (F) (N) (O) presented a Rout slightly above the thresh- old value and no clinical improvement after tap test. All these patients, however, showed a good improvement in perfusion values in PVWM and BG. Patients were subsequently submitted to surgery. A month after VP- shunt implantation these patients showed good clinical improvement and CBF values increased even more. This finding suggests that perfusion MRI (a non-invasive tech- nique) could enhance the selection of candidates for VP shunt implantation.
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Comparison of semi quantitative and quantitative dynamic contrast enhanced MRI evaluations of vertebral marrow perfusion in a rat osteoporosis model

Comparison of semi quantitative and quantitative dynamic contrast enhanced MRI evaluations of vertebral marrow perfusion in a rat osteoporosis model

To the best of our knowledge, few longitudinal animal- based studies have compared semi-quantitative with quan- titative DCE-MRI to determine which better reflects the perfusion condition in OP. In our study, acute estrogen deficiency caused a significant decrease in K trans of the bone marrow from week 3 after OVX. It was identified by TEM observation, which showed vascular endothelial dys- function appearing as tighter gaps between VECs with swollen mitochondria. Gulhan et al. [16] reported that postmenopausal women with OP may have an association with higher endothelin-1levels than those without OP. Animal studies indicated that the tendency of increased endothelin-1 serum levels in the OVX rats was one of the most likely causes of enhanced vasoconstriction and de- creased permeability [2]. These findings strongly support the hypothesis that vascular endothelial dysfunction after OVX induced low bone marrow perfusion at an early stage [1]. It is notable that no significant change on MVD calculation was found between the OVX and control group until week 12. This phenomenon implies that the decrease in K trans of the OVX group in the late stage may be attributed to the decrease of MVD in the bone marrow. Our study also found that the V e values of the OVX group
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Preliminary study of CT in combination with MRI perfusion imaging to assess hemodynamic changes during angiogenesis in a rabbit model of lung cancer

Preliminary study of CT in combination with MRI perfusion imaging to assess hemodynamic changes during angiogenesis in a rabbit model of lung cancer

was observed in these tumor lesions, and extensive malignant pleural effusion, pleural dissemination, and numerous mediastinal lymph node metastases was found at necropsy. Another limitation of our study was the mismatch between perfusion parameters and pathological measurements at an early stage, because of differences in the time points when CT and MRI scans were performed and the times when pathology measurements were done. The relationship between perfusion parameters and pathological findings in early tumor growth requires further investigation.

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Brain perfusion in dementia with Lewy bodies and Alzheimer’s disease: an arterial spin labeling MRI study on prodromal and mild dementia stages

Brain perfusion in dementia with Lewy bodies and Alzheimer’s disease: an arterial spin labeling MRI study on prodromal and mild dementia stages

The results for focal relative perfusion in prodromal patients are presented in Table 2 and Fig 1. Hypoperfusion in pro DLB compared to HC occurred in the right frontal, parietal, and temporal cortex together with the anterior insula. Only the left superior frontal gyrus showed an increase in relative perfusion in pro DLB. Absolute hypop- erfusion gave similar results with a loss of perfusion in the right temporal and anterior insula, whereas the left supe- rior frontal gyrus was hyperperfused (Additional file 1: Table S1 and Figure S1. Please refer to these supple- mentary data for all results of absolute perfusion). Pro AD showed hypoperfusion compared to HC in the right inferior frontal gyrus and bilateral angular gyrus, and hyperperfusion was seen in the left supramarginal gyrus (absolute assessment showed a similar pattern of hypop- erfusion, but without any increase in perfusion relative to HC). Comparison between pro DLB and pro AD revealed a lower relative perfusion in DLB in the fusiform gyrus (as with absolute measurements). Pro AD did not have any
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