Cerebral Blood Volume Values Research Articles

Regional cerebral hypoperfusion as a cause of symptoms and progression of multiple sclerosis

Background. Neurodegenerative processes play an important role in the development of clinical features of multiple sclerosis (MS) as well as in the progression of the disease. At the same time, neurodegenerative mechanisms of MS are not completely clear, which makes researchers pay special attention to pathogenetic aspects of the disease that have not been studied before. Previously it was shown that MS patients can have alterations in the local cerebral blood flow, however, the meaning of the detected abnormalities is still not clear.The aim of our workis to evaluate the perfusion character in the demyelinating lesions and normalappearing brain structures, and to determine their relation to clinical features of MS.Material and methods. 49 patients with relapsing-remitting and secondary progressive MS with clinical and MRI remission were included in the study. The patients underwent contrast-enhanced MR perfusion of the brain on the 3 Tesla MR-tomograph, as well as the Functional System Score, Expanded Disability Status Score and Fatigue Status Score evaluation. The data analysis included automatic construction of perfusion maps of the cerebral blood volume (CBV), cerebral blood flow (CBF) and mean transit time (MTT) values in the normal-appearing brain structures and in the demyelinating lesions and statistical analysis.Results. The received results allow to presume that variation of CBV values in MS lesions can indicate heterogeneity of processes in these lesions – from reactivation of inflammation to remyelination.Significant reduction of perfusion in nucleus lenticularis was revealed. This reduction did not depend on the severity of the disease and correlated negatively with the fatigue score. This allows to suppose that the therapy focused on brain perfusion improvement can be used as symptomatic therapy of MS. Considering the fact that regional hypoperfusion precedes the development of brain structure atrophy, it is hypothesized that the improvement of perfusion may prevent neurodegeneration in MS. The obtained findings need further investigation.

T2/FLAIR-mismatch sign for noninvasive detection of IDH-mutant 1p/19q non-codeleted gliomas: validity and pathophysiology.

BackgroundThis study aimed to assess the validity and pathophysiology of the T2/FLAIR-mismatch sign for noninvasive identification of isocitrate dehydrogenase (IDH)-mutant 1p/19q non-codeleted glioma.MethodsMagnetic resonance imaging scans from 408 consecutive patients with newly diagnosed glioma (113 lower-grade gliomas and 295 glioblastomas) were evaluated for the presence of T2/FLAIR-mismatch sign by 2 independent reviewers. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the performance of the T2/FLAIR-mismatch sign for identifying IDH-mutant 1p/19q non-codeleted tumors. An exploratory analysis of differences in contrast-enhancing tumor volumes, apparent diffusion coefficient (ADC) values, and relative cerebral blood volume (rCBV) values in IDH-mutant gliomas with versus without the presence of a T2/FLAIR-mismatch sign (as well as analysis of spatial differences within tumors with the presence of a T2/FLAIR-mismatch sign) was performed.ResultsThe T2/FLAIR-mismatch sign was present in 12 cases with lower-grade glioma (10.6%), all of them being IDH-mutant 1p/19q non-codeleted tumors (sensitivity = 10.9%, specificity = 100%, PPV = 100%, NPV = 3.0%, accuracy = 13.3%). There was a substantial interrater agreement to identify the T2/FLAIR-mismatch sign (Cohen’s kappa = 0.75 [95% CI, 0.57–0.93]). The T2/FLAIR-mismatch sign was not identified in any other molecular subgroup, including IDH-mutant glioblastoma cases (n = 5). IDH-mutant gliomas with a T2/FLAIR-mismatch sign showed significantly higher ADC (P < .0001) and lower rCBV values (P = .0123) as compared to IDH-mutant gliomas without a T2/FLAIR-mismatch sign. Moreover, in IDH-mutant gliomas with T2/FLAIR-mismatch sign the ADC values were significantly lower in the FLAIR-hyperintense rim as compared to the FLAIR-hypointense core of the tumor (P = .0005).ConclusionsThis study confirms the high specificity of the T2/FLAIR-mismatch sign for noninvasive identification of IDH-mutant 1p/19q non-codeleted gliomas; however, sensitivity is low and applicability is limited to lower-grade gliomas. Whether the higher ADC and lower rCBV values in IDH-mutant gliomas with a T2/FLAIR-mismatch sign (as compared to those without) translate into a measurable prognostic effect requires investigation in future studies. Moreover, spatial differences in ADC values between the core and rim of tumors with a T2/FLAIR-mismatch sign potentially reflect specific distinctions in tumor cellularity and microenvironment.

Value of Apparent Diffusion Coefficient and Relative Cerebral Blood Volume Calculated by MRI for Grading of Brain Tumors

AbstractBackground: MRI is the standard technique for diagnosis of brain tumors, but the challenge is determination of brain tumor grade.Aim of Study: To assess the role of Apparent Diffusion Coefficient (ADC) and relative Cerebral Blood Volume (rCBV) in brain tumors grading.Patients and Methods: Our prospective comparative analytic study involved 26 patients that were diagnosed to have brain tumors. All patients were subjected to revision of their medical history, full neurological and cognitive functions assessment, anatomical brain assessment by conventional MRI examination of the brain, diffusion and perfusion MRI with measurement of mADC & rCBV values respectively. Correlation of results with the histopathological findings of the resected tumors as a gold standard were performed.Results: The diagnostic capability of mADC by using cut off value of 3.22 & >2.33) with significant difference in between (p=0.001 & 0.002). The diagnostic capability of rCBV by using cut off value of >3.22 & >2.33, had a sensitivity of 68.4%, 90.9 respectively and a specificity of 100% at p-value of <0.00. Multivariant logistic regression revealed that rCBV higher than 2.33 and mADC !91281.34 fitted the statistical regression for prediction of high grade tumors in intra-axial brain tumors (p=0.002).Conclusion: Diffusion and perfusion imaging are useful for characterizing intra-axial brain tumors. rCBV measurement can be used to determine the grade of glioma with no added advantage of ADC map.

Blood-Brain Barrier Disruption as a Potential Target for Therapy in Posterior Reversible Encephalopathy Syndrome: Evidence From Multimodal MRI in Rats.

Background: To explore blood–brain barrier disruption in hypertensive posterior reversible encephalopathy syndrome.Methods: The hypertension rat models were successfully established and scanned on 7T micro-MRI. MRI parameter maps including apparent diffusion coefficient, T1 value, and perfusion metrics such as cerebral blood volume, cerebral blood flow, mean transit time and time to peak maps, were calculated.Results: The ADC values of the experimental group were higher than those of the control group both in cortical (P < 0.01) and subcortical (P < 0.05) regions. Voxel-wise analysis of ADC maps localized vasogenic edema primarily to the posterior portion of the brain. The increase in cerebral blood volume and cerebral blood flow values were found in the cortical and subcortical regions of rats with acute hypertension. No correlation was found between perfusion metrics and mean arterial pressure. The Evans blue dye content was higher in the posterior brain region than the anterior one (P < 0.05).Conclusions: Cerebral vasogenic edema resulting from acute hypertension supports the hypothesis of posterior reversible encephalopathy syndrome as the result of blood–brain barrier disruption, which maybe the potential therapeutic target for intervention.

Regional cerebral perfusion correlates with anxiety in neuropsychiatric SLE: evidence for a mechanism distinct from depression.

The study examined the hypothesis that hypoperfusion in brain areas known to be involved in emotional disturbances in primary psychiatric disorders is also linked to emotional difficulties in systemic lupus erythematosus (SLE) and that these are not secondary to the physical and social burden incurred by the disease. Nineteen SLE patients without overt neuropsychiatric manifestations (non-NPSLE), 31 NPSLE patients, and 23 healthy controls were examined. Dynamic susceptibility contrast MRI was used and cerebral blood flow and cerebral blood volume values were estimated in six manually selected regions of interest of brain regions suspected to play a role in anxiety and depression (dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate cortex, hippocampi, caudate nuclei and putamen). NPSLE patients reported high rates of anxiety and depression symptomatology. Significantly reduced cerebral blood flow and cerebral blood volume values were detected in the NPSLE group compared to healthy controls in the dorsolateral prefrontal cortex and ventromedial prefrontal cortex, bilaterally. Within the NPSLE group, anxiety symptomatology was significantly associated with lower perfusion in frontostriatal regions and in the right anterior cingulate gyrus. Importantly, the latter associations appeared to be specific to anxiety symptoms, as they persisted after controlling for depression symptomatology and independent of the presence of visible lesions on conventional MRI. In conclusion, hypoperfusion in specific limbic and frontostriatal regions is associated with more severe anxiety symptoms in the context of widespread haemodynamic disturbances in NPSLE.

NIMG-28. VALIDATION OF SINGLE-DOSE DSC-MRI PROTOCOLS FOR ROBUST PERFUSION ASSESSMENT IN BRAIN TUMORS

Abstract Dynamic susceptibility contrast (DSC) MRI measures of brain tumor cerebral blood volume (CBV) are able to predict grade, overall survival and response to treatment. Wide-spread acceptance of DSC-MRI has been challenged by the need to balance contrast agent dose and CBV accuracy. The goal of this study was to identify and validate single-dose, BTIP compliant, DSC-MRI protocols. Using a validated, patient-based DRO, we evaluated CBV accuracy across a range of acquisition parameters (field strength, TR, TE, flip angle, multi-echo acquisitions, dosing protocols) and post-processing steps. To validate the optimal protocols, we next collected DSC-MRI data following ASFNR’s recommended “double – dose” approach, where a single-dose preload (to minimize T1 effects) is given prior to a second bolus injection (for DSC-MRI data acquisition). The single-dose DSC-MRI data was collected during the preload bolus injection. Consistency of the derived CBV data, visual agreement and data characteristics (e.g. CNR) was statistically evaluated. When using a single-dose and routine single-echo pulse sequence, the DRO analysis found that a low flip angle (LFA = 30o) and 30ms TE provided the highest CBV accuracy (concordance correlation coefficient (CCC) = 0.92) and precision (coefficient of variation (CV) = 8.2%)). For comparison, the maximum accuracy found with the DRO utilizes a double-dose injection protocol and yielded a CCC of 0.98 and CV of 6.8%. Single-dose, multi-echo acquisitions provided higher accuracy than the LFA data and matched that found with the double-dose approach. In patients (data collection ongoing), the agreement between single-dose LFA (n &gt; 40) or multi-echo (n &gt; 40) based CBV values and the reference double-dose approach was very high (CCC &gt; 0.94) and were statistically equivalent. Optimized single-dose DSC-MRI protocols provide highly accurate CBV data, use lower doses of contrast agent, and simplify scan procedures, indicating their potential for robust use in clinical practice and trials.

Blood CT pefusion analysis of cerebral gray matter and white matter in supply region of chronic cerebral artery occlusion

Objective To study the different ischemic characteristics of cerebral gray matter and deep white matter in patients with chronic cerebral artery severe stenosis or occlusion. Methods A retrospective study was conducted on 30 patients with chronic unilateral cerebral artery severe stenosis or occlusion from April 2014 to April 2018 in our hospital. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time of peak time (TTP) and time to delay(TTD) of cerebral cortex gray matter and deep white matter in the blood supply area of the responsible artery (the affected side) and the contralateral hemisphere (the healthy side) were measured. Statistical analysis of the perfusion parameters of cerebral cortex gray matter and deep white matter in the affected side and contralateral side were performed using SPSS13.0 software package. T test was used for variance homogeneity, and t′ test was used for variance discrepancy, and P<0.05 was statistically significant. Results The average values of CBF and CBV of the ipsilateral and contralateral cerebral cortex were increased than those of ipsilateral and contralateral cerebral deep white matter respectively(P<0.01). MTT, TTP and TTD of the ipsilateral and contralateral cerebral cortex were decreased than that of ipsilateral and contralateral cerebral deep white matter (P<0.01); CBF of ipsilateral cerebral cortex and CBV of ipsilateral cerebral deep white matter were not different from those of the contralateral cerebral cortex and deep white matter respectively, but CBF of ipsilateral cerebral deep white matter is decreased than that of the contralateral deep white matter (P<0.01). CBV of ipsilateral cerebral cortex is increased than that of the contralateral cerebral cortex (P<0.01). MTT, TTP and TTD of ipsilateral cerebral cortex and deep white matter were increased than those of contralateral cerebral cortex and deep white matter respectively(P<0.01). Conclusion Deep cerebral white matter perfusion decreased more significantly than cortical gray matter in the supply region of chronic cerebral artery severe stenosis or occlusion. CT perfusion imaging can quantify the degree of chronic cerebral ischemia and can provide quantitative diagnostic information for clinical treatment and efficacy evaluation. Key words: Cerebral arteries; Tomography, X-ray computed; Stenosis; Occlusion

Statistical properties of cerebral CT perfusion imaging systems. Part I. Cerebral blood volume maps generated from nondeconvolution-based systems.

The development and clinical employment of a computed tomography (CT) imaging system benefit from a thorough understanding of the statistical properties of the output images; cerebral CT perfusion (CTP) imaging system is no exception. A series of articles will present statistical properties of CTP systems and the dependence of these properties on system parameters. This Part I paper focuses on the signal and noise properties of cerebral blood volume (CBV) maps calculated using a nondeconvolution-based method. The CBV imaging chain was decomposed into a cascade of subimaging stages, which facilitated the derivation of analytical models for the probability density function, mean value, and noise variance of CBV. These models directly take CTP source image acquisition, reconstruction, and postprocessing parameters as inputs. Both numerical simulations and in vivo canine experiments were performed to validate these models. The noise variance of CBV is linearly related to the noise variance of source images and is strongly influenced by the noise variance of the baseline images. Uniformly partitioning the total radiation dose budget across all time frames was found to be suboptimal, and an optimal dose partition method was derived to minimize CBV noise. Results of the numerical simulation and animal studies validated the derived statistical properties of CBV. The statistical properties of CBV imaging systems can be accurately modeled by extending the linear CT systems theory. Based on the statistical model, several key signal and noise characteristics of CBV were identified and an optimal dose partition method was developed to improve the image quality of CBV.

Diagnostic accuracy of flat-panel computed tomography in assessing cerebral perfusion in comparison with perfusion computed tomography and perfusion magnetic resonance: a systematic review

PurposeFlat-panel computed tomography (FP-CT) is increasingly available in angiographic rooms and hybrid OR’s. Considering its easy access, cerebral imaging using FP-CT is an appealing modality for intra-procedural applications. The purpose of this systematic review is to assess the diagnostic accuracy of FP-CT compared with perfusion computed tomography (CTP) and perfusion magnetic resonance (MRP) in cerebral perfusion imaging.MethodsWe performed a systematic literature search in the Cochrane Library, MEDLINE, Embase, and Web of Science up to June 2019 for studies directly comparing FP-CT with either CTP or MRP in vivo. Methodological quality was assessed using the QUADAS-2 tool. Data on diagnostic accuracy was extracted and pooled if possible.ResultsWe found 11 studies comparing FP-CT with CTP and 5 studies comparing FP-CT with MRP. Most articles were pilot or feasibility studies, focusing on scanning and contrast protocols. All patients studied showed signs of cerebrovascular disease. Half of the studies were animal trials. Quality assessment showed unclear to high risks of bias and low concerns regarding applicability. Five studies reported on diagnostic accuracy; FP-CT shows good sensitivity (range 0.84–1.00) and moderate specificity (range 0.63–0.88) in detecting cerebral blood volume (CBV) lesions.ConclusionsEven though FP-CT provides similar CBV values and reconstructed blood volume maps as CTP in cerebrovascular disease, additional studies are required in order to reliably compare its diagnostic accuracy with cerebral perfusion imaging.

Advanced imaging parameters improve the prediction of diffuse lower-grade gliomas subtype, IDH mutant with no 1p19q codeletion: added value to the T2/FLAIR mismatch sign

A combination of T2/FLAIR mismatch sign and advanced imaging parameters may improve the determination of molecular subtypes of diffuse lower-grade glioma. We assessed the diagnostic value of adding the apparent diffusion coefficient (ADC) and cerebral blood volume (CBV) to the T2/FLAIR mismatch sign for differentiation of the IDH mutation or 1p/19q codeletion. Preoperative conventional, diffusion-weighted, and dynamic susceptibility contrast imaging were performed on 110 patients with diffuse lower-grade gliomas. The study population was classified into three groups using molecular subtype, namely IDH mutation and 1p/19q codeletion (IDHmut-Codel), IDH wild type (IDHwt) and IDH mutation and no 1p/19q codeletion (IDHmut-Noncodel). T2/FLAIR mismatch sign and the histogram parameters of apparent diffusion coefficient (ADC) and normalised cerebral blood volume (nCBV) values were assessed. A multivariate logistic regression model was constructed to distinguish IDHmut-Noncodel from IDHmut-Codel and IDHwt and from IDHwt, and the performance was compared with that of single parameters using the area under the receiver operating characteristics curve (AUC). Positive visual T2/FLAIR mismatch sign and higher nCBV skewness were significant variables to distinguish IDHmut-Noncodel from the other two groups (AUC, 0.88; 95% CI, 0.81-0.96). A lower ADC10 was a significant variable for distinguishing IDHmut-Noncodel from the IDHwt group (AUC, 0.75; 95% CI, 0.62-0.89). Adding ADC or CBV histogram parameters to T2/FLAIR mismatch sign improved performance in distinguishing IDHmut-Noncodel from the other two groups (AUC 0.882 vs. AUC 0.810) or from IDHwt (AUC 0.923 vs. AUC 0.868). The combination of the T2/FLAIR mismatch sign with ADC or CBV histogram parameters can improve the identification of IDHmut-Noncodel diffuse lower-grade gliomas, which can be easily applied in clinical practice. • The combination of the T2/FLAIR mismatch sign with the ADC or CBV histogram parameters can improve the identification of IDHmut-Noncodel diffuse lower-grade gliomas. • The multivariable model showed a significantly better performance for distinguishing the IDHmut-Noncodel group from other diffuse lower-grade gliomas than the T2/FLAIR mismatch sign alone or any single parameter. • The IDHmut-Noncodel type was associated with intermediate treatment outcomes; therefore, the identification of IDHmut-Noncodel diffuse lower-grade gliomas could be helpful for determining the clinical approach.

The value of contrast-enhanced T1 mapping technique in differentiating recurrence and radiation necrosis of brain metastases after gamma knife treatment

Objective To explore the value of contrast-enhanced T1 mapping technique in differentiating between recurrence and radiation necrosis of brain metastases after gamma knife treatment. Methods From March 2016 to June 2017,56 patients with brain metastases treated by gamma knife and confirmed by pathology or follow-up in Shandong Provincial Hospital were prospectively collected. Routine MRI and contrast-enhanced T1 mapping sequence scan were performed. T1 value was obtained 5 mins (T1 5min) and 60 mins (T1 60min) after injection of contrast agent. The Differences betweenT1 60 min and T1 5 min (T1differ) was calculated,and relative cerebral blood volume (rCBV) value was obtained. Patients were divided into radiation necrosis group and tumor recurrence group according to imaging follow-up results or pathological results. Two-sides unpaired t test was used to compare the differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups. Pearson correlation analysis was used to evaluate the correlation between T1 differ and rCBV,and the receiving operating curve (ROC) was used to evaluate the diagnostic efficiency of MRI quantitative parameters,and Z test was used to compare the differences of area under curve (AUC) between T1 differ and rCBV values. Results Of the 56 patients,27 had tumor recurrence and 29 had radiation necrosis. The differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups was statistically significant (P<0.05). T1 differ and rCBV values were significantly correlated,r=0.58,P<0.01. The differential diagnosis of AUC between radiation necrosis and tumor recurrence were 0.66,0.73,0.97 and 0.95 respectively in T1 5min,T1 60 min,T1 differ and rCBV,and there was no significant differences between AUC in T1 differ and rCBV (P=0.274). Conclusion The contrast-enhanced T1 mapping image can be used for differential diagnosis between radiation necrosis and recurrence after gamma knife treatment of brain metastases. T1 differ value has high differential efficiency. Key words: Brain neoplasms; Neoplasm metastasis; T1 mapping; Radiation necrosis; Recurrence of tumor; Gamma knife treatment

Measurement of the Absolute Value of Cerebral Blood Volume and Optical Properties in Term Neonates Immediately after Birth Using Near-Infrared Time-Resolved Spectroscopy: A Preliminary Observation Study

The aim of this study was to use near-infrared time-resolved spectroscopy (TRS) to determine the absolute values of cerebral blood volume (CBV) and cerebral hemoglobin oxygen saturation (ScO2) during the immediate transition period in term neonates and the changes in optical properties such as the differential pathlength factor (DPF) and reduced scattering coefficient (μs’). CBV and ScO2 were measured using TRS during the first 15 min after birth by vaginal delivery in term neonates who did not need resuscitation. Within 2–3 min after birth, CBV showed various changes such as increases or decreases, followed by a gradual decrease until 15 min and then stability (mean (SD) mL/100 g brain: 2 min, 3.09 (0.74); 3 min, 3.01 (0.77); 5 min, 2.69 (0.77); 10 min, 2.40 (0.61), 15 min, 2.08 (0.47)). ScO2 showed a gradual increase, then kept increasing or became a stable reading. The DPF and μs’ values (mean (SD) at 762, 800, and 836 nm) were stable during the first 15 min after birth (DPF: 4.47 (0.38), 4.41 (0.32), and 4.06 (0.28)/cm; μs’: 6.54 (0.67), 5.82 (0.84), and 5.43 (0.95)/cm). Accordingly, we proved that TRS can stably measure cerebral hemodynamics, despite the dramatic physiological changes occurring at this time in the labor room.

PROSEDUR PEMERIKSAAN MAGNETIC RESONANCE IMAGING (MRI) BRAIN PERFUSI DENGAN METODE ARTERIAL SPIN LABELING (ASL) PADA PASIEN TUMOR

Background : Examination procedure of Magnetic resonance imaging (MRI) Brain Perfusion in patient with tumor disease at Radiology Department of National Brain Hospital used the MR Perfusion sequence with the Dynamic Susceptibility Contrast (DSC) method with the addition of Arterial Spin Labeling (ASL) method which was also used to determine CBF values. Nevertheless CBF values can also be obtained from the use of the DSC method. The application of these two roles in patient with tumor disease certainly has their respective roles in providing accurate information for the diagnosis. The purpose of this study was to determine the role of the application of MR perfusion with the Arterial Spin Labeling (ASL) method and the Dynamic Susceptibility Contrast (DSC) method for the diagnosis of patient with tumor disease at Radiology Department of National Brain Hospital.&#x0D; Methods :The type of this research is qualitative with case study approach. The data were collected from March – April 2019 at at Radiology Department of National Brain Hospital by using observation method, interview with radiology specialist doctor, sending doctor, FGD, and documentation. Data obtained from the study were analyzed by making the transcript then reduced in the form of categorization table and open coding, presented in quote form and then can be drawn conclusion.&#x0D; Result : Brain perfusion MRI examination procedures in tumor patients begin with examination preparation, preparation of tools and materials, carry out the examination using the MRI Brain protocol with contrast and without contrast. The use of contrast uses the Dynamic Susceptibility Contrast (DSC) method and non-contrast use using the Arterial Spin Labeling (ASL) method where both complement each other to inform perfusion parameter values.&#x0D; Conclusion : The conclution of this study indicate still needed the application of both MR perfusion methods, namely the ASL method and the DSC method. The ASL method will provide additional information in the form of absolute values of Cerebral Blood Flow that are not affected by permeability, besides that the DSC method is able to provide Cerebral Blood Volume values that are used as a parameter of Perfusion MR evaluation.&#x0D; Keyword : ASL, DSC, Tumor, CBF&#x0D;

Interferon-free therapy as the cause of white matter tracts and cerebral perfusion recovery in patients with chronic hepatitis C.

The purpose of this study was to assess cerebral microstructural and perfusion changes in patients with chronic hepatitis C virus (HCV) infection before and after interferon-free therapy, using advanced magnetic resonance (MR) techniques. Eleven HCV-positive patients underwent diffusion tensor imaging (DTI) and perfusion-weighted imaging (PWI) using a 1.5T MR unit, before and 24weeks after completion of interferon-free therapy. DTI fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained from 14 white matter tracts. PWI values of relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) were assessed from 8 areas, including basal ganglia, and cortical and white matter locations. In HCV-positive patients therapy with ombitasvir, paritaprevir boosted with ritonavir and dasabuvir, with or without ribavirin, was scheduled. Cognitive tests were used to assess cognitive function. We found increased FA values after interferon-free therapy compared to values obtained before treatment in HCV patients in almost all white matter tracts. We also observed elevated rCBV values in basal ganglia after therapy. There were significant correlations between improvement in the score of cognitive tests and increased FA values in both inferior fronto-occipital fascicles and left posterior cingulum after treatment. Liver fibrosis regression in elastography, APRI and improvement in cognitive tests were observed. This is the first report of interferon-free therapy as the cause of white matter tracts recovery as well as cerebral perfusion improvement in HCV-infected patients, indicating better functioning of frontal lobes after interferon-free treatment.

Neuro-radiological characteristics of adult diffuse grade II and III insular gliomas classified according to WHO 2016.

The phenotypic heterogeneity of diffuse gliomas is still inconsistently explained by known molecular abnormalities. Here, we report the molecular and radiological features of diffuse grade WHO II and III gliomas involving the insula and its potential impact on prognosis. Clinical, pathological, molecular and neuro-radiological features of 43 consecutive patients who underwent a surgical resection between 2006 and 2013 for a grade II and III gliomas involving the insula was retrospectively analyzed. Median age was 44.4years. Eight patients had oligodendrogliomas, IDH mutant (IDHmut) and 1p/19q-codeleted (6 grade II, 2 grade III). Twenty-eight patients had diffuse astrocytomas, IDHmut (22 grade II and 6 grade III) and seven patients had grade II diffuse astrocytomas, IDHwt (A-IDHwt). Vimentin staining was exclusively recorded in tumor cells from A-IDHwt (p = 0.001). Mean cerebral blood volume (CBV) (p = 0.018), maximal value of CBV (p = 0.017) and ratio of the corrected CBV (p = 0.022) were lower for A-IDHwt. Volumetric segmentation of ADC allowed the identification of the tumor cores, which were smaller in A-IDHwt (p < 0.001). The tumor occurrences of A-IDHwt were exclusively located into the temporo-insular region. Median progression-free survival (PFS) and overall survival (OS) were 50.9months (95% CI: 26.7-75.0) and 80.9months (60.1-101.6). By multivariate analysis, A-IDHwt (p = 0.009; p = 0.019), 7p gain and 10q loss (p = 0.009; p = 0.016) and vimentin positive staining (p = 0.011; p = 0.029) were associated with poor PFS and OS respectively. Insular low-grade A-IDHwt presented with poor prognosis despite a smaller tumor core and no evidence of increased perfusion on MR imaging.

Cerebral blood volume mapping using Fourier-transform-based velocity-selective saturation pulse trains.

Velocity-selective saturation (VSS) pulse trains provide a viable alternative to the spatially selective methods for measuring cerebral blood volume (CBV) by reducing the sensitivity to arterial transit time. This study is to compare the Fourier-transform-based velocity-selective saturation (FT-VSS) pulse trains with the conventional flow-dephasing VSS techniques for CBV quantification. The proposed FT-VSS label and control modules were compared with VSS pulse trains utilizing double refocused hyperbolic tangent (DRHT) and 8-segment B1-insensitive rotation (BIR-8). This was done using both numerical simulations and phantom studies to evaluate their sensitivities to gradient imperfections such as eddy currents. DRHT, BIR-8, and FT-VSS prepared CBV mapping was further compared for velocity-encoding gradients along 3 orthogonal directions in healthy subjects at 3T. The phantom studies exhibited more consistent immunity to gradient imperfections for the utilized FT-VSS pulse trains. Compared to DRHT and BIR-8, FT-VSS delivered more robust CBV results across the 3 VS encoding directions with significantly reduced artifacts along the superior-inferior direction and improved temporal signal-to-noise ratio (SNR) values. Average CBV values obtained from FT-VSS based sequences were 5.3 mL/100 g for gray matter and 2.3 mL/100 g for white matter, comparable to literature expectations. Absolute CBV quantification utilizing advanced FT-VSS pulse trains had several advantages over the existing approaches using flow-dephasing VSS modules. A greater immunity to gradient imperfections and the concurrent tissue background suppression of FT-VSS pulse trains enabled more robust CBV measurements and higher SNR than the conventional VSS pulse trains.

The Radiological Imaging Features of Easily Misdiagnosed Epithelioid Glioblastoma in Seven Patients

We review the radiological imaging features and report histopathological findings of 7 adult patients with epithelioid glioblastoma (eGBM), which was a newly revised subtype of glioblastoma. Seven adult patients with a diagnosis of eGBM on a brain tissue specimen were retrospectively confirmed by pathology. The tumor magnetic resonance imaging characteristics such as location, number, edema, necrosis, hemorrhage, enhancement, diffusion-weighted image, apparent diffusion coefficient, magnetic resonance spectroscopy, dynamic susceptibility contrast-perfusion-weighted imaging, and histopathological findings were documented. The tumors of these patients exhibited iso-hyperintensive signal on the T2-weighted image and iso-hypointensive signal on the T1-weighted image. All the lesions manifested iso-hypointensive signal on the diffusion-weighted image, and 2 cases showed significantly restricted hyperintensive signal (2/7). Peritumoral edema in all cases was mild. Five cases were located in the cortical lobe (5/7) and the other 2 were multifocal (2/7). Four cases showed white matter collapse sign (4/7). These tumors revealed apparent enhancement after contrast injection. In particular, 4 cases displayed capsuled sign (4/7), 2 cases showed dura mater tail sign (2/7), and 1 case showed hemorrhage (1/7). The mean value of apparent diffusion coefficient in 6 cases was 1.09× 10-3 mm2/s. The mean value of relative cerebral blood volume in 3 cases was 2.84× 10-3 mm2/s on dynamic susceptibility contrast-perfusion-weighted imaging. The average value of the choline/N-acetyl aspartate ratio in 4 cases was 6.47× 10-3 mm2/s on magnetic resonance spectroscopy. All cases expressed a BRAF V600E mutation according to molecular characteristics. eGBMs that were predominantly located in cortex with mild peritumoral edema, white matter collapse, encapsular sign, and dura mater tail sign could be easily misdiagnosed as cortex-involved intracranial brain tumor such as meningioma, whereas multifocal tumors could be easily misdiagnosed as metastatic tumor and lymphoma. Multimodal images were helpful for the differential diagnosis.

Apparent Diffusion Coefficient as a Predictive Biomarker for Survival in Patients with Treatment-Naive Glioblastoma Using Quantitative Multiparametric Magnetic Resonance Profiling

The purpose of the present study was to investigate whether quantitative radiomic profiles extracted from multiparametric magnetic resonance (MR) profiles can predict the clinical outcomes for patients with newly diagnosed glioblastoma (GBM) before therapy. MR images from 93 treatment-naive patients with newly diagnosed GBM were analyzed. Through tumor segmentation, we selected 36 radiomic features. Using the unsupervised clustering method, we classified our patients into 2 groups and investigated their overall survival (OS) using Kaplan-Meier analyses. Among the 36 radiomic features, the apparent diffusion coefficient (ADC) histogram parameters demonstrated a significant association with OS (P < 0.05). To validate this finding, unsupervised clustering analysis revealed 3 clusters with similar radiomic expression patterns. Clusters 1 and 2 showed a significant correlation with the radiomic features representing the tumor volume, and cluster 2 also showed a significant correlation with relative cerebral blood volume values. In contrast, cluster 3 showed an inverse relationship with cluster 2, mainly representing the radiomic features indicating the ADC and mean transit time. Although no statistically significant difference was found in OS between cluster 1 plus 2 and cluster 3, cluster 3 showed a trend toward longer OS compared with cluster 1 plus 2 (P= 0.067). After stratification by methylation status and radiomic feature clustering, patients with methylated O6-methylguanine DNA methyltransferase and those included in cluster 3 had significantly longer OS (P= 0.029). ADC histogram parameters are feasible prognostic biomarkers to predict the survival of patients with treatment-naive GBM. Quantitative MR profiles can predict the clinical outcomes of patients with GBM before therapy.

Perfusion magnetic resonance imaging in differentiation of neurocysticercosis and tuberculoma.

Tuberculoma and neurocysticercosis (NCC) are two of the most common intracranial infections in developing countries and cause of seizures or focal neurological deficit. They often present on neuroimaging as ring-enhancing lesions, and in absence of typical imaging features, can cause significant diagnostic dilemma. Differentiation is extremely important to avoid empirical exposure to anti-tubercular treatment or nonspecific treatment causing disease progression. The aim our study was to evaluate the MR perfusion characteristics of brain tuberculoma and NCC and to assess the potential role of the perfusion in differentiating the two entities. Fifty untreated patients (20 tuberculoma and 30 NCC) were prospectively evaluated by using conventional imaging and dynamic susceptibility contrast (DSC) MR perfusion. Relative cerebral blood volume (rCBV) values were calculated from the wall and core of the lesion and were compared with contralateral normal white matter. rCBV values from the wall of the lesion were significantly different in tuberculoma and NCC (P < 0.05). Tuberculomas showed high mean rCBV values than NCC (3.3 and 1.3 respectively). The core of these lesions showed lower rCBV values in both the lesions which were lower than normal white matter. A cutoff value of rCBV from the wall of the lesion 1.965 for tuberculoma showed 90% sensitivity and 100% specificity. Perfusion MRI in combination with conventional sequences can better characterize and differentiate similar-appearing tuberculoma and NCC and may be incorporated in routine protocol which may help in avoiding brain biopsy and empirical therapy.

CT, conventional, and functional MRI features of skull lymphoma: a series of eight cases in a single institution.

With the hypothesis that the combination of CT, conventional, and functional MRI can indicate a possible diagnosis of skull lymphoma, this study aimed to systematically explore CT, conventional, and functional MRI features of this rare entity. This retrospective study included eight patients with pathologically confirmed skull lymphomas. CT and conventional MRI findings, including the location, size, attenuation/signal intensity, cystic/necrosis, hemorrhage, calcification, enhancement, skull change, brain parenchyma edema and adjacent structure invasion, were reviewed. We also reviewed multi-parametric functional MR imaging features obtained from diffusion-weighted imaging (DWI, n = 4), susceptibility-weighted imaging (SWI, n = 3) and dynamic susceptibility-weighted contrast-enhanced perfusion-weighted imaging (DSC-PWI, n = 1). The eight patients in this series consisted of five males and three females, with a mean age of 51.1years. All skull lymphomas showed the tumors extending to extra- and intra-cranial spaces with permeative destruction of the intervening skull. Intratumoral cystic/necrosis was seen in one case. Hemorrhage or calcification was absent. Dural mater infiltration was detected in all cases. Two clivus lymphomas encased internal carotid artery without narrowing the lumen. Three cases invaded brain parenchyma with moderate edema. The tumors demonstrated high signal on DWI with low ADC values comparing to muscles. SWI images showed little intratumoral hemorrhage and vessel. Low relative cerebral blood volume (rCBV) value was detected. Skull lymphomas commonly presented as a homogenous solid tumor extending either intra- or extra-cranially with permeative bone destruction. Restricted diffusion, little intratumoral susceptibility signal, and lower perfusion may indicate a specific diagnosis. Multi-parametric functional MRI may be a promising tool for the diagnosis of skull lymphomas.