Value Of Arterial Spin Labeling Research Articles

Exploring brain perfusion in dogs with meningoencephalitis of unknown origin: A promising role for arterial spin labeling imaging.

Arterial spin labeling (ASL) is a noninvasive brain perfusion magnetic resonance imaging (MRI) technique that has not been assessed in dogs with meningoencephalitis of unknown origin (MUO). Assess brain perfusion changes characteristics before and after medical treatment, and investigate the role of ASL perfusion in the diagnosis and prognosis of MUO in dogs. Thirty-one dogs with presumed MUO. Prospective study. Each animal had brain MRI including standard and ASL perfusion sequences at presentation and after treatment of 3 months or longer. Brain perfusion characteristics were assessed visually and by cerebral blood flow (CBF) measurements. Perfusion characteristics were compared pre- and post-treatment. Dogs with MUO had preferential localization of lesions in optic nerves (ONs) and brainstem. At presentation, one third of the dogs with MUO had focal brain perfusion alterations and two-thirds had global brain hypoperfusion. Both focal and global brain perfusion changes resolved after treatment in all surviving dogs. Arterial spin labeling failed to predict prognosis. Brain ASL perfusion in dogs with MUO demonstrated the value of ASL in the diagnosis and follow-up of the condition, suggesting the value of adding ASL to the clinical evaluation in dogs with suspected MUO. Preferential lesion localization in ON and brainstem resembled findings in the central nervous system of human patients with inflammatory demyelinating diseases. Future studies with histopathological confirmation are needed to better characterize the benefits of ASL in the different subtypes of non-infectious encephalomyelitis in dogs.

Exploring the value of arterial spin labeling and six diffusion MRI models in differentiating solid benign and malignant renal tumors

ObjectiveTo explore the value of three-dimensional arterial spin labeling (ASL) and six diffusion magnetic resonance imaging (MRI) models in differentiating solid benign and malignant renal tumors.MethodsThis retrospective study included 89 patients with renal tumors. All patients underwent ASL and ZOOMit diffusion-weighted imaging (DWI) examinations and were divided into three groups: clear cell renal cell carcinoma (ccRCC), non-ccRCC, and benign renal tumors (BRT). The mean and peak renal blood flow (RBFmean and RBFpeak) from ASL and fourteen diffusion parameters from mono-exponential DWI (Mono_DWI), intravoxel incoherent motion (IVIM), diffusion kurtosis imaging (DKI), stretched exponential model (SEM), fractional order calculus (FROC), and continuous-time random-walk (CTRW) model were analyzed. Binary logistic regression was used to determine the optimal parameter combinations. The diagnostic performance of various MRI-derived parameters and their combinations was compared.ResultsAmong the six diffusion models, the SEM model achieved the highest performance in differentiating ccRCC from non-ccRCC (area under the receiver operating characteristic curve [AUC] 0.880) and from BRT (AUC 0.891). IVIM model achieved the highest AUC (0.818) in differentiating non-ccRCC from BRT. Among all the MRI-derived parameters, RBFpeak combined with DKI_MK yielded the highest AUC (0.970) in differentiating ccRCC from non-ccRCC, and the combination of RBFpeak, SEM_DDC, and FROC_μ yielded the highest AUC (0.992) for differentiating ccRCC from BRT.ConclusionASL and all diffusion models showed similar diagnostic performance in differentiating ccRCC from non-ccRCC or BRT, while the IVIM model performed better in distinguishing non-ccRCC from BRT. Combining ASL with diffusion models can provide additional value in predicting ccRCC.Relevance statementConsidering the increasing detection rate of incidental renal masses, accurate discrimination of benign and malignant renal tumors is crucial for decision-making. Combining ASL with diffusion MRI models offers a promising solution to this clinical issue.Key PointsAll assessed models were effective for differentiating ccRCC from non-ccRCC or BRT.ASL and all diffusion models showed similar performance in differentiating ccRCC from non-ccRCC or BRT.Combining ASL with diffusion models significantly improved diagnostic efficacy in predicting ccRCC.IVIM model could better differentiate non-ccRCC from BRT.Graphical

Arterial spin labeling combined with T1 mapping for assessment of kidney function and histopathology in patients with long-term renal transplant survival after kidney transplantation.

The long-term survival of kidney transplants is often influenced by various factors, among which renal allograft rejection is the most notable factor. A noninvasive and reliable imaging biomarker correlating with kidney function and histopathology would facilitate longitudinal long-term follow-up of renal allografts. The aim of the study is to investigate the value of arterial spin labeling (ASL) combined with T1 mapping for assessing kidney function in patients with long-term renal transplant survival, and to establish radiological and histopathologic correlations between the magnetic resonance imaging (MRI) measurements and kidney allograft biopsy findings. Kidney transplant recipients who were admitted to the Department of Urology in First Affiliated Hospital of Soochow University between January and December 2022 were prospectively consecutively recruited [group A, estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2; group B, 30≤ eGFR <60 mL/min/1.73 m2; group C, eGFR <30 mL/min/1.73 m2], and part of them underwent biopsies. All patients underwent ASL and T1 mapping. MRI parameters were calculated and analyzed. A total of 63 patients (Group A, 30 cases; Group B, 20 cases; and Group C, 13 cases) were included in this cross-sectional study. Cortical T1 increased, whereas renal blood flow (RBF) and ΔT1 [100% × (cortical T1 - medullary T1)/cortical T1] decreased with the decrease of eGFR. The RBF, cortical T1, and ΔT1 values were moderately correlated with eGFR (r=0.569, -0.573, and 0.672, respectively). The MRI parameters were moderately correlated with Banff scores, which determined renal allograft rejection and chronicity. The area under the curve (AUC) for the discrimination of groups A versus B and groups A versus C were 0.740 [95% confidence interval (CI): 0.597-0.854, P=0.004] and 0.923 (95% CI: 0.800-0.982, P<0.001), respectively, using ASL; 0.873 (95% CI: 0.749-0.950, P<0.001) and 0.926 (95% CI: 0.803-0.983, P<0.001), respectively, using T1 mapping; and 0.892 (95% CI: 0.771-0.962, P<0.001) and 0.956 (95% CI: 0.846-0.995, P<0.001), respectively, using multi-parameter MRI. The AUC for discrimination between groups B and C was 0.729 (95% CI: 0.546-0.868, P=0.02) using ASL. The RBF, cortical T1, and ΔT1 can serve as new imaging biomarkers of kidney function and histopathological microstructure.

Evaluation of Kidney Injury Using Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI: An Experimental Study in Rats With Carbon Tetrachloride-Induced Liver Cirrhosis.

Serum creatinine (Scr) may be not suited to timely and accurately reflect kidney injury related to chronic liver disease. Currently, the ability of arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) sequences to evaluate renal blood flow (RBF) and blood oxygen in chronic liver disease remains to be verified. To investigate the value of ASL and BOLD imaging in evaluating hemodynamics and oxygenation changes during kidney injury in an animal model of chronic liver disease. Prospective. Chronic liver disease model was established by subcutaneous injection of carbon tetrachloride. Forty-three male Sprague-Dawley rats (8 weeks) were divided into a pathological group (0, 2, 4, 6, 8, 12 weeks, each group: N = 6) and a continuous-scanning group (N = 7). 3-T, ASL, BOLD, and T2W. Regions of interest in the cortex (CO), outer stripe of the outer medulla (OSOM), and inner stripe of the outer medulla (ISOM) are manually delineated. The RBF and T2* values at each time point (0, 2, 4, 6, 8, 12 weeks) are measured and compared. Hematoxylin-eosin score (HE Score, damage area scoring method), alpha-smooth muscle actin (α-SMA), hypoxia-inducible factor-1alpha (HIF-1α), peritubular capillar (PTC) density, Scr, and neutrophil gelatinase-associated lipocalin were harvested. Analysis of variance, Spearman correlation analysis, Kruskal-Wallis tests, and receiver operating characteristic analysis with the area under the curve (AUC). A P-value <0.05 was considered statistically significant. Renal RBF and T2* values of CO, OSOM, and ISOM were significantly different from baseline. Both RBF and T2* were significantly correlated with HE Score, α-SMA, HIF-1α, and PTC density (|r| = 0.406-0.853). RBF demonstrated superior diagnostic capability in identifying severe kidney injury in this model of chronic liver disease (AUC = 0.964). Imaging by ASL and BOLD may detect renal hemodynamics and oxygenation changes related to chronic liver disease early. 5 TECHNICAL EFFICACY: Stage 2.

Arterial spin labeling in assessment of interstitial fibrosis in renal allografts

Objective: To explore the feasibility and application value of arterial spin labeling (ASL) in evaluating the degree of renal fibrosis after kidney transplantation. Methods: This is a cross-sectional study. Renal transplant recipients who received treatment at the First Affiliated Hospital of Soochow University from December 2021 to December 2022 were enrolled. All participants underwent ASL scan, and the values of renal cortical renal blood flow (RBF) were measured through post-processing software. The participants were divided into different groups according to the Banff interstitial fibrosis score (ci score) of the transplanted kidneys, and then relevant indicators were compared. One-way analysis of variance was conducted to compare the differences in renal cortical RBF among the groups. Spearman correlation analysis was employed to investigate the association between renal cortical RBF and ci score of the transplanted kidney. Receiver operating characteristic curve was used to analyze the diagnostic effectiveness of renal cortical RBF and laboratory indicators for distinguishing varying degrees of fibrosis in transplanted kidneys. The Delong test was utilized to compare the area under the curve (AUC). Results: A total of 60 patients (42 males and 18 females) were included in the study, with a mean age of (44.6±10.8) years. All patients were divided into 4 groups: ci0 group (ci score=0, 11 cases), ci1 group (ci score=1, 21 cases), ci2 group (ci score=2, 20 cases), and ci3 group (ci score=3, 8 cases). With an increase in the degree of fibrosis in the transplanted kidney, there was a corresponding decrease in the renal cortical RBF value. The differences in renal cortical RBF values among the 4 groups were statistically significant[ci0 group: (214.9±28.5) ml·(100 g)-1·min-1; ci1 group: (181.7±29.3) ml·(100 g)-1·min-1; ci2 group: (158.8±39.2) ml·(100 g)-1·min-1; ci3 group: (123.1±27.2) ml·(100 g)-1·min-1; F=14.02, P<0.001]. The renal cortical RBF was moderately negatively correlated with the ci score (r=-0.644, P<0.001). The AUC for discriminating between ci0 and ci1-3 of renal cortical RBF and 24-hour urine protein was 0.881 (95%CI: 0.772-0.950) and 0.680 (95%CI: 0.547-0.795), respectively. The AUC for renal cortical RBF was significantly higher than that for 24-hour urine protein (P=0.047). The renal cortical RBF can distinguish between ci0-1 and ci2-3, as well as ci0-2 and ci3, with the corresponding AUC value of 0.796 (95%CI: 0.673-0.889) and 0.900 (95%CI: 0.795-0.963), respectively. Conclusion: ASL can quantitatively assess renal blood perfusion in transplanted kidneys and demonstrates high operational efficacy in distinguishing varying degrees of fibrosis in the transplanted kidneys.

Diagnostic value of arterial spin labeling for Alzheimer's disease: A systematic review and meta-analysis.

Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique that offers a non-invasive approach for measuring cerebral blood perfusion (CBF). CBF serves as a marker of neuronal activity, and ASL has demonstrated the potential to detect reductions in CBF associated with early-stage neurodegenerative diseases like Alzheimer's disease (AD). Consequently, ASL has garnered growing interest as a potential diagnostic tool for AD. Despite the promise of ASL for diagnosing AD, there is a paucity of data regarding the pooled specificity and sensitivity of this technique in this context. The purpose of this systematic review and meta-analysis is to identify the accuracy of ASL in the diagnosis of AD with international clinical diagnosis as the gold standard. Four English databases and four Chinese databases were searched from their inception to 30 November 2023. Two independent reviewers extracted relevant information from the eligible articles, while the quality assessment of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). The meta-analysis was carried out using the area under the Receiver Operator Characteristic (ROC) curves (AUC) and sensitivity and specificity values. Meta-DiSc 1.4 was used to perform the statistical analysis. STATA 16.0 was used to perform publication bias and sensitivity analysis. Of 844 relevant articles retrieved, 10 studies involving 494 participants (AD patients = 262, healthy controls = 232) met the inclusion criteria and were included in the meta-analysis. However, the quality of studies was low based on QUADAS-2. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of ASL for diagnosing AD was 0.83 (95% CI: 0.78-0.87), 0.81 (95% CI: 0.76-0.86), 4.52 (95% CI: 3.40-6.00), 0.22 (95% CI: 0.17-0.28), and 19.31(95% CI: 12.30-30.31), respectively. The pooled AUC = 0.8932. There was low heterogeneity across the included studies. Finally, sensitivity analysis suggested that the results were reliable. ASL is an effective and accurate method for the diagnosis of AD. However, due to the limited quantity and quality of the included studies, the above conclusions need to be verified by more studies. PROSPERO registration number: CRD42023484059.

P15.06.B Influence of arterial transit time delays on the differentiation between tumor progression and pseudo-progression in glioblastoma by arterial spin labeling MRI

Abstract Background Perfusion MRI by Arterial Spin Labeling (ASL) and Dynamic Susceptibility Contrast (DSC) has shown its potential for differentiating tumor progression from pseudo-progression in glioblastoma patients. The ASL scans can be affected by arterial transit time (ATT) delays, which could be caused by treatment effects due to concomitant radiochemotherapy. A prolonged ATT is present as apparent signal increase in the large arteries due to labeled spins still residing within the vasculature, leading to underestimation of tissue perfusion and thus potentially affecting clinical decision-making. The research questions were: 1) Do delayed ATTs lead to a difference in the visual assessment of ASL perfusion (normal/increased) maps compared to DSC-MRI?; 2) Does the radiological evaluation (progression vs. pseudo-progression) of ASL and DSC perfusion maps differ when ATT artifacts are present?; 3) Do delayed ATTs affect the predictive value of ASL-MRI scans 3 months post-radiotherapy for detecting true disease progression? Material and Methods This retrospective, single-center study included 68 adult patients with histologically confirmed glioblastoma who received postoperative radio(chemo)therapy. ASL and DSC scans were acquired 3 months post-radiotherapy as part of routine clinical follow-up. The perfusion data were visually scored by a neuroradiologist who determined presence/absence of ATT artifacts and their severity (%), perfusion of the enhancing tumor lesion and the radiological evaluation of tumor progression versus pseudo-progression. Presence of true disease progression was determined by follow-up of clinical data until 9 months post-radiotherapy available for 49/68 patients. Logistic regression was performed with gender, age, treatment type and tumor genetic status as covariates to assess the predictive value of ASL. Results In 78% of the patients ATT artifacts were present. No statistically significant association between the agreement of the perfusion maps and presence of ATT artifacts was found, but presence of ATT artifacts lowered the agreement between the DSC and ASL radiological evaluation. The logistic regression analysis showed that the ASL-based radiological score could not predict true disease progression, whereas higher age and unmethylated MGMT gene were associated with progression. Presence of ATT artifacts was not associated with tumor progression. Conclusion The presence of delayed ATT in ASL data seems to impact the radiological evaluation of ASL data, steering interpretation towards tumor progression (as compared to the DSC evaluation), whereas in patients without ATT artifacts ASL and DSC provide more similar radiological scores. Therefore, it is highly recommended to consider these artifacts when interpreting ASL perfusion MRI to differentiate between tumor progression and pseudo-progression in glioblastoma patients.

Arterial Spin Labeling Imaging Characteristics of Anti-leucine-rich Glioma-Inactivated 1 Encephalitis: A Qualitative and Quantitative Analysis.

Background and SignificanceAutoimmune encephalitis (AE) is a rare group of diseases that can present with stroke-like symptoms. Anti-leucine-rich glioma inactivated 1 (LGI1) encephalitis is an AE subtype that is infrequently associated with neoplasms and highly responsive to prompt immunotherapy treatment. Therefore, accurate diagnosis of LGI1 AE is essential in timely patient management. Neuroimaging plays a critical role in evaluating stroke and stroke mimics such as AE. Arterial Spin Labeling (ASL) is an MRI perfusion modality that measures cerebral blood flow (CBF) and is increasingly used in everyday clinical practice for stroke and stroke mimic assessment as a non-contrast sequence. Our goal in this preliminary study is to demonstrate the added value of ASL in detecting LGI1 AE for prompt diagnosis and treatment.MethodsIn this retrospective single center study, we identified six patients with seropositive LGI1 AE who underwent baseline MRI with single delay 3D pseudocontinuous ASL (pCASL), including five males and one female between ages 28 and 76 years, with mean age of 55 years. Two neuroradiologists qualitatively interpreted the ASL images by visual inspection of CBF using a two-point scale (increased, decreased) when compared to both the ipsilateral and contralateral unaffected temporal and non-temporal cortex. The primary measures on baseline ASL evaluation were a) presence of ASL signal abnormality, b) if present, signal characterization based on the two-point scale, c) territorial vascular distribution, d) localization, and e) laterality. Quantitative assessment was also performed on postprocessed pCASL cerebral blood flow (CBF) maps. The obtained CBF values were then compared between the affected temporal cortex and each of the unaffected ipsilateral parietal, contralateral temporal, and contralateral parietal cortices.ResultsOn consensus qualitative assessment, all six patients demonstrated ASL hyperperfusion and corresponding FLAIR hyperintensity in the hippocampus and/or amygdala in a non-territorial distribution (6/6, 100%). The ASL hyperperfusion was found in the right hippocampus or amygdala in 5/6 (83%) of cases. Four of the six patients underwent initial follow-up imaging where all four showed resolution of the initial ASL hyperperfusion. In the same study on structural imaging, all four patients were also diagnosed with mesial temporal sclerosis (MTS). Quantitative assessment was separately performed and demonstrated markedly increased CBF values in the affected temporal cortex (mean, 111.2 ml/min/100 g) compared to the unaffected ipsilateral parietal cortex (mean, 49 ml/min/100 g), contralateral temporal cortex (mean, 58.2 ml/min/100 g), and contralateral parietal cortex (mean, 52.2 ml/min/100 g).DiscussionIn this preliminary study of six patients, we demonstrate an ASL hyperperfusion pattern, with a possible predilection for the right mesial temporal lobe on both qualitative and quantitative assessments in patients with seropositive LGI1. Larger scale studies are necessary to further characterize the strength of these associations.

Arterial spin labeling of nasopharyngeal carcinoma shows early therapy response

ObjectiveThis study aimed to determine the value of arterial spin labeling (ASL) perfusion imaging in assessing the early efficacy of chemoradiotherapy for nasopharyngeal carcinoma (NPC).MethodsFifty-five patients with locoregionally advanced NPC underwent conventional 3.0-T magnetic resonance imaging (MRI) and ASL before and after chemoradiotherapy (prescribed dose reached 40 Gy). Based on the response evaluation criteria for solid tumors (RECIST 1.1), the patients were divided into the partial response and stable disease groups. MRI re-examination was performed one month after chemoradiotherapy completion, and patients were divided into residual and non-residual groups. We investigated inter-group differences in ASL-based tumor blood flow (TBF) parameters (pre-treatment tumor blood flow, post-treatment tumor blood flow, and changes in tumor blood flow, i.e., Pre-TBF, Post-TBF, ΔTBF), correlation between TBF parameters and tumor atrophy rate, and value of TBF parameters in predicting sensitivity to chemoradiotherapy.ResultsThere were differences in Pre-TBF, Post-TBF, and ΔTBF between the partial response and stable disease groups (p < 0.01). There were also differences in Pre-TBF and ΔTBF between the residual and non-residual groups (p < 0.01). Pre-TBF and ΔTBF were significantly correlated with the tumor atrophy rate; the correlation coefficients were 0.677 and 0.567, respectively (p < 0.01). Pre-TBF had high diagnostic efficacies in predicting sensitivity to chemoradiotherapy and residual tumors, with areas under the curve of 0.845 and 0.831, respectively.ConclusionASL permits a noninvasive approach to predicting the early efficacy of chemoradiotherapy for NPC.

Added Value of Arterial Spin Labeling in Detecting Posterior Reversible Encephalopathy Syndrome as a Stroke Mimic on Baseline Neuroimaging: A Single Center Experience.

Differentiating stroke from stroke mimics is a diagnostic challenge in every day practice. Posterior Reversible Encephalopathy Syndrome (PRES) is an important stroke mimic with nonspecific symptomatology, making prompt and accurate diagnosis challenging. Baseline neuroimaging plays a pivotal role in detection and differentiation of stroke from many common mimics and is thus critical in guiding appropriate management. In particular, MR perfusion (MRP) imaging modalities provide added value through detection and quantification of multiple physiological parameters. Arterial Spin Labeling (ASL) is a non-contrast, noninvasive MRP technique increasingly used in clinical practice; however, there is limited description of ASL in PRES in the existing literature. In this single center retrospective pilot study, we investigate the added value of ASL in detecting PRES in the largest series to date. We hope this study can serve as the basis for larger scale investigations exploring the utility of ASL in detecting stroke mimics such as PRES for accurate and efficient management of such patients.

Usefulness of arterial spin labeling perfusion as an initial evaluation of status epilepticus

This study aimed to evaluate the sensitivity and prognostic value of arterial spin labeling (ASL) in a large group of status epilepticus (SE) patients and compare them with those of other magnetic resonance (MR) sequences, including dynamic susceptibility contrast (DSC) perfusion imaging. We retrospectively collected data of patients with SE in a tertiary center between September 2016 and March 2020. MR images were visually assessed, and the sensitivity for the detection of SE and prognostication was compared among multi-delay ASL, DSC, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI). We included 51 SE patients and 46 patients with self-limiting seizures for comparison. Relevant changes in ASL were observed in 90.2% (46/51) of SE patients, a percentage higher than those for DSC, FLAIR, and DWI. ASL was the most sensitive method for initial differentiation between SE and self-limiting seizures. The sensitivity of ASL for detecting refractory SE (89.5%) or estimating poor outcomes (100%) was higher than those of other MR protocols or electroencephalography and comparable to those of clinical prognostic scores, although the specificity of ASL was very low as 9.4% and 15.6%, respectively. ASL showed a better ability to detect SE and predict the prognosis than other MR sequences, therefore it can be valuable for the initial evaluation of patients with SE.

Improving the image quality and quantitative accuracy of arterial spin labeling based on generative adversarial network

Objective: To investigate the use of deep learning approaches to improve the image quality of arterial spin labeling (ASL) and optimize its quantitative accuracy for cerebral blood flow (CBF). Methods: The clinical and imaging data of 101 patients with cerebrovascular disease in Tianjin Huanhu Hospital from May 2018 to August 2019 were retrospectively collected. Patients were divided into a training set (71 cases) and a validation set (30 cases). In training set, there were 53 cases of male,18 cases of female,with age of 55.0 (41.3, 64.5), and in validation set, there were 23 cases of male,7 cases of female,with age of57.5 (49.0, 65.0). Quantitative perfusion weighted imaging was used as the reference standard, and the original ASL-CBF images were reconstructed by training a deep learning generative adversarial network (GAN). The image quality of original ASL-CBF and GAN-CBF was compared by the structural similarity index and the normalized root mean square error. Pearson correlation coefficient was used to analyze the correlation between ASL-CBF, GAN-CBF and quantitative perfusion in different cerebral vascular blood supply areas and stroke areas, and to verify the improvement effect of GAN on the image quality and quantitative accuracy of ASL. Results: There were significant differences in gender, age, disease type, site and size between training set and validation set (all P>0.05). Compared with ASL-CBF, GAN-CBF had a higher structural similarity index (0.888 vs 0.801, P<0.001), and a lower normalized root mean square error (0.628 vs 0.775, P<0.001). The correlation between GAN-CBF and quantitative perfusion in different blood vessel supply areas and stroke lesion areas was improved compared with the original ASL-CBF, in which the perforating branch of the middle artery (r=0.853) and stroke lesion areas (r=0.765) were the most obvious (all P<0.001). Conclusion: The generative adversarial network could improve the image quality and quantization accuracy of ASL without increasing the scanning time, and expand the clinical application value of ASL.

Characterizing spatiotemporal progression and prediction of infarct lesion volumes in experimental acute ischemia using quantitative perfusion and diffusion imaging

PurposeThis study was conducted to explore the diagnostic value of arterial spin labeling (ASL) combined with diffusion weighted imaging (DWI) in characterizing the spatiotemporal progression of infarct lesions in a rabbit middle cerebral artery occlusion (MCAO) model and predicting the acute cerebral infarction (ACI) volume. Materials and methodsForty-two male rabbits (2.9 ± 0.2 kg body weight) were used in this experimental study. Animals were initially anesthetized by intravenous injection of uratan. There were seven experimental groups with six rabbits in each group. The apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) thresholds were established in the control group (n = 6), which were sacrificed at 12 h, stained for infarct volume, and imaged at each time point. ResultsThe normal ADC and CBF were estimated as 0.90 ± 0.03 × 10−3 mm2/s and 0.68 ± 0.06 mL g−1 min−1, respectively. The viability thresholds of ADC and CBF yielding the lesion volumes (LVs) at 3 h, which best approximated the 2,3,5-triphenyltetrazolium chloride (TTC) infarct volumes at 12 h, were 0.52 ± 0.02 × 10−3 mm2/s (42.2 ± 3% reduction) and 0.33 ± 0.09 mL g−1 min−1 (51.0 ± 11% reduction), respectively. The temporal evolution of the ADC- and CBF-defined LVs showed a significant perfusion/diffusion mismatch up to 1 h (p = 0.001). ConclusionADC values and ACI volumes were positively correlated, while CBF was negatively correlated, which is supposed to be a reference for predicting ACI volume.

Cerebral Perfusion Associates with Short-term Clinical Outcomes of Cerebral Venous Thrombosis

Background: To investigate the predictive value of Arterial Spin Labeling (ASL) perfusion imaging for short-term clinical outcomes of cerebral venous thrombosis (CVT) patients.

Investigating the value of arterial spin labeling and intravoxel incoherent motion imaging on diagnosing nasopharyngeal carcinoma in T1 stage

BackgroundTo investigate the diagnostic value of arterial spin labeling (ASL) and intravoxel incoherent motion (IVIM) imaging in distinguishing nasopharyngeal carcinoma (NPC) in T1 stage from healthy controls (HC).MethodsForty-five newly diagnosed NPC patients in the T1 stage and thirty-one healthy volunteers who underwent MR examinations for both 3D pseudo-continuous ASL (pCASL) and IVIM were enrolled in this study. The Mann-Whitney test was used to compare the mean values of blood flow (BF) derived from pCASL and IVIM derived parameters, including apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion coefficient (D*) and perfusion fraction (f) between NPC tumor and benign nasopharyngeal mucosa of HC. Receiver Operating Characteristic (ROC) was performed to determine diagnostic cutoff and efficiency. The correlation coefficients among parameters were investigated using Spearman’s test.ResultsThe NPC in the T1 stage showed higher mean BF, lower ADC, D, and f compared to benign nasopharyngeal mucosa (P < 0.001) with the area under curve of ROC of 0.742–0.996 (highest by BF). BF cutoff was set at > 36 mL/100 g/min; the corresponding sensitivity, specificity, and accuracy in differentiating NPC stage T1 from benign nasopharyngeal mucosa were 95.56% (43/45), 100% (31/31) and 97.37% (74/76), respectively. BF demonstrated moderate negative correlation with D* on HC (ρ [Spearman correlation coefficients] = − 0.426, P = 0.017).ConclusionsASL and IVIM could reflect the difference in perfusion and diffusion between tumor and benign nasopharyngeal mucosa, indicating a potential for accessing early diagnosis of NPC. Notably, BF, with a specificity of 100%, demonstrated better performance compared to IVIM in distinguishing malignant lesions from healthy tissue.

Cerebral Perfusion Does Not Increase after Shunt Surgery for Normal Pressure Hydrocephalus.

Cerebral blood flow (CBF) has been reported to increase after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH). The aims of this study were to investigate if CBF, measured using the noninvasive perfusion MRI method arterial spin labeling (ASL), increased after shunt surgery, if postoperative change in CBF correlated with improvement in symptoms, and if baseline CBF data correlated with postoperative outcome. Twenty-three patients with iNPH were prospectively included and examined with MRI of the brain and clinical tests of symptoms at baseline. Eighteen of the patients were treated with shunt implantation and were reexamined with clinical tests and MRI 3 months postoperatively. The MRI protocol included a pseudo-continuous ASL sequence for perfusion imaging. The perfusion was measured in 12 manually drawn regions of interest (ROIs). In the whole sample, CBF did not increase after shunting in any ROI. PreoperativeCBF in medial frontal cortex correlated with an improvement in urinary incontinence after shunt surgery,r = .53, P = .022. There were no correlations between change in CBF and change in clinical symptoms postoperatively. The clinical value of ASL in the work-up of patients with iNPH is uncertain. In this study, ASL could not predict outcome after shunt surgery and there were no correlations between change in CBF and change in clinical symptoms after shunt surgery.

Arterial Spin-Labeling in Children with Brain Tumor: A Meta-Analysis.

The value of arterial spin-labeling in a pediatric population has not been assessed in a meta-analysis. Our aim was to assess the diagnostic accuracy of arterial spin-labeling-derived cerebral blood flow to discriminate low- and high-grade tumors. MEDLINE, EMBASE, the Web of Science Core Collection, and the Cochrane Library were used. Pediatric patients with arterial spin-labeling MR imaging with verified neuropathologic diagnoses were included. Relative CBF and absolute CBF and tumor grade were extracted, including sequence-specific information. Mean differences in CBF between low- and high-grade tumors were calculated. Study quality was assessed. Data were aggregated using the bivariate summary receiver operating characteristic curve model. Heterogeneity was explored with meta-regression and subgroup analyses. The study protocol was published at PROSPERO (CRD42017075055). Eight studies encompassing 286 pediatric patients were included. The mean differences in absolute CBF were 29.62 mL/min/100 g (95% CI, 10.43-48.82 mL/min/100 g), I2 = 74, P = .002, and 1.34 mL/min/100 g (95% CI, 0.95-1.74 mL/min/100 g), P < .001, I2 = 38 for relative CBF. Pooled sensitivity for relative CBF ranged from 0.75 to 0.90, and specificity, from 0.77 to 0.92 with an area under curve = 0.92. Meta-regression showed no moderating effect of sequence parameters TE, TR, acquisition time, or ROI method. Included tumor types, analysis method, and original data varied among included studies. Arterial spin-labeling-derived CBF measures showed high diagnostic accuracy for discriminating low- and high-grade tumors in pediatric patients with brain tumors. The relative CBF showed less variation among studies than the absolute CBF.

How far is arterial spin labeling MRI from a clinical reality? Insights from arterial spin labeling comparative studies in Alzheimer's disease and other neurological disorders.

How far is arterial spin labeling MRI from a clinical reality? Insights from arterial spin labeling comparative studies in Alzheimer's disease and other neurological disorders.

Spin labeling artery method perfusion MRI study of SPG4 and SCA3/MJD

BackgroundSpinocerebellar ataxia type 3 (SCA3) and Machado–Joseph disease (MJD) are similar diseases that are often referred to jointly as SCA3/MJD. As the most common autosomal-dominantly inherited subtype of hereditary spastic paraplegia (HSP), HSP4 (or SPG4) has overlapping symptoms with SCA3/MJD, which hinders their diagnoses. Arterial spin labeling (ASL) is a noninvasive, contrast-agent free, magnetic resonance perfusion imaging method used to obtain maps of the cerebral blood flow (CBF). Here, we investigated the diagnostic value of ASL in SCA3/MJD and SPG4 patients. MethodsA total of 13 SPG4 cases, 38 SCA3/MJD cases (22 onset patients and 16 genetic abnormality-only patients), and 27 healthy volunteers were examined by ASL. Data were processed to obtain the regional CBF (rCBF) and comparatively studied. ResultsIn the pons, cerebellar dentate nucleus, and cerebellar cortex, rCBF of the onset SCA3/MJD group was significantly lower than that of the normal control group. In the cerebellar dentate nucleus and cerebellar cortex, the rCBF of the non-onset SCA3/MJD group was significantly lower than that of the control group. In the pons and cerebellar cortex, the rCBF of the onset SCA3/MJD group was significantly lower than that of the SPG4 group. ConclusionsSCA3/MJD lesions are mainly located in the cerebellum and brainstem. Gray matter and white matter were both involved, although the deep cerebellar nuclei may be the earliest involved region. Cerebellar and brainstem lesions of SCA3/MJD were more severe than those of SPG4. ASL can aid the diagnosis of SCA3/MJD and SPG4.

Prognostic value of blood flow estimated by arterial spin labeling and dynamic susceptibility contrast-enhanced MR imaging in high-grade gliomas.

Several studies evaluated the predictive value of dynamic susceptibility contrast enhanced (DSC) imaging and arterial spin labeling (ASL) with regard to histological grade. Yet still less is known about their significance in terms of patients prognosis. Our purpose was to evaluate the agreement between them and the prognostic value of ASL- and DSC-CBF measurements for time-to-recurrence (TTR). Sixty nine cases of WHO Grade 3-4 gliomas underwent both DSC- and ASL-MRI. Normalized ASL and DSC-based cerebral blood flow (CBF) maps as well as DSC-derived cerebral blood volume maps (CBV) were analyzed. Wilcoxon test and Bland-Altman plot analysis were applied in order to compare DSC-rCBF and ASL-rCBF. Spearman's rank correlation coefficients were determined for all perfusion parameters. Receiver operating characteristic (ROC) curve and survival curve analyses were performed. The median values of ASL-rCBF, DSC-rCBF, and DSC-rCBV were 5.3, 6.9, and 8.0, respectively. There was neither significant correlation nor difference between ASL-rCBF and DSC-rCBF. Slight proportional bias was demonstrated in the Bland-Altman plot analysis of ASL-rCBF and DSC-rCBF values. Unlikely to DSC-rCBV, DSC- and ASL-based rCBF parameters demonstrated moderate sensitivity and specifitity for tumor recurrence but no statistical significance regarding their prognostic values for TTR in the Kaplan-Meier analysis. There were neither correlation nor interchangeability between the DSC-rCBF and ASL-rCBF estimations, which demonstrated comparable, though not significant prognostic value for the prediction of TTR. rCBV measurements seem to provide the best sensitivity and specificity to predict tumor recurrence and survival time in these patients.