How does the subjective well-being of Australian adults with a congenital corpus callosum disorder compare with that of the general Australian population?

PURPOSE: Very little is known about the subjective well-being (SWB) of adults with a congenital corpus callosum disorder (CCD), the extent to which they feel satisfied with their lives, and what might be helpful in improving their SWB and quality of life. This study measured SWB among Australian adults with a CCD and compared the results with normative data for the wider Australian adult population. METHODS: Online surveys were completed independently by 53 Australian adults with a CCD. Data included demographic profiles and answers to questions about satisfaction with life, employing the Personal Wellbeing Index (PWI) and one open ended question. Domains measured included life as a whole, standard of living, health, achieving in life, personal relationships, safety, community connectedness and future security. The PWI results were statistically analysed and means compared with Australian normative data. The qualitative data were analysed using deductive thematic analysis. RESULTS: Australian adults with a CCD responded with ratings significantly below what might be expected of the adult Australian population in all domains except for standard of living and safety. Quantitative analysis results were supported by qualitative thematic analysis, expressing particular challenges and barriers to feeling satisfaction with life as a whole, personal relationships, achieving in life, health and future security. CONCLUSION: Evidence from the PWI and accompanying qualitative responses indicate that SWB of Australian adults with CCD is significantly reduced compared with the general population. Further research is needed to examine the lived experience and explore solutions for support of this community.

Very little is known about the quality of life and personal well-being of Australian adults who have a corpus callosum disorder (CCD), a rare brain condition with complex impacts ranging from mild to severe. People with a CCD are born missing part or all of their corpus callosum, the connecting body between the two halves of the brain. This study asked adults with a CCD to rate their own personal wellbeing in an online questionnaire and the results were compared with those of the general Australian population. Participants were also asked to describe how a CCD affected their lives in their own words. We found that adults with a CCD have significantly lower personal wellbeing than the general Australian population. The most concerning issues were with relationships, life achievements, mental health and not having a secure future. The results tell us that we need to explore personal wellbeing in more depth using research methods in which adults with a CCD can tell us more about the impacts of a CCD on their lives. We need to ask how they think the quality of their lives could be improved and what supports would help to achieve that.

Post-COVID-19 conditions: a systematic review on advanced magnetic resonance neuroimaging findings.

Post-COVID conditions (PCCs) cover a wide spectrum of lingering symptoms experienced by survivors of coronavirus disease 2019 (COVID-19). Neurological and neuropsychiatric sequelae are common in PCCs. Advanced magnetic resonance imaging (MRI) techniques can reveal subtle alterations in brain structure, function, and perfusion that underlie these sequelae. This systematic review aimed to synthesize findings from studies that used advanced MRI to characterize brain changes in individuals with PCCs. A detailed literature search was conducted in the PubMed and Scopus databases to identify relevant studies that used advanced MRI modalities, such as structural MRI (sMRI), diffusion tensor imaging (DTI), functional MRI (fMRI), and perfusion-weighted imaging (PWI), to evaluate brain changes in PCCs. Twenty-five studies met the inclusion criteria, comprising 1219 participants with PCCs. The most consistent findings from sMRI were reduced gray matter volume (GMV) and cortical thickness (CTh) in cortical and subcortical regions. DTI frequently reveals increased mean diffusivity (MD), radial diffusivity (RD), and decreased fractional anisotropy (FA) in white matter tracts (WMTs) such as the corpus callosum, corona radiata, and superior longitudinal fasciculus. fMRI demonstrated altered functional connectivity (FC) within the default mode, salience, frontoparietal, somatomotor, subcortical, and cerebellar networks. PWI showed decreased cerebral blood flow (CBF) in the frontotemporal area, thalamus, and basal ganglia. Advanced MRI shows changes in the brain networks and regions of the PCCs, which may cause neurological and neuropsychiatric problems. Multimodal neuroimaging may help understand brain-behavior relationships. Longitudinal studies are necessary to better understand the progression of these brain anomalies.

Assessing the influence of migraine on ischemic penumbra and on the prognosis of ischemic stroke: A prospective cohort study.

INTRODUCTION: There is controversy as to whether migraine affects the behavior of ischemic penumbra during the acute phase of an ischemic stroke, thereby accelerating the formation of cerebral infarction. OBJECTIVES: To assess whether migraine modifies the existence and volume of the divergence between the areas of diffusion and perfusion in the stroke (the penumbra) and whether migraine implies a poorer prognosis after the stroke. METHODS: This was a prospective cohort study. We included hospitalized patients with ischemic stroke within 72 h of symptom onset (convenience sampling). A semi-structured questionnaire, the National Institute of Health Stroke Scale, and the modified Rankin Scale (mRS) were used. Patients underwent magnetic resonance imaging (MRI) of the brain with diffusion and with perfusion. Patients were assessed by telephone 3 months after the stroke to determine the prognosis. Scores of > 2 on the mRS were considered to have a poor prognosis. RESULTS: A total of 221 patients were included, 131/221 (59%) of whom were male, and with a mean (SD) age of 68.2 (13.8) years. Ischemic penumbra analysis was performed in 118 patients. There was no association between migraine and the absence of ischemic penumbra (16/63 [25%] vs. 12/55 [22%]; odds ratio 1.22, 95% confidence interval 0.52-2.87; p = 0.64). There was no difference in stroke volume between those with and without migraine (median [interquartile range] 1.0 [0.4-7.9] vs. 1.8 [0.3-9.4] cm3 ; p = 0.99). Migraine was not associated with the stroke prognosis after multivariable analysis. CONCLUSION: Migraine is not associated with the absence of ischemic penumbra, the volume of the ischemic penumbra, or the stroke prognosis.

Magnetic resonance imaging-derived parameters to predict response to regorafenib in recurrent glioblastoma.

PURPOSE: Regorafenib is a multikinase inhibitor, approved as a preferred regimen for recurrent glioblastoma (rGB). Although its effects on prolonging survival could seem modest, it is still unclear whether a subset of patients, potentially identifiable by imaging biomarkers, might experience a more substantial positive effect. Our aim was to evaluate the potential value of magnetic resonance imaging-derived parameters as non-invasive biomarkers to predict response to regorafenib in patients with rGB. METHODS: 20 patients with rGB underwent conventional and advanced MRI at diagnosis (before surgery), at recurrence and at first follow-up (3 months) during regorafenib. Maximum relative cerebral blood volume (rCBVmax) value, intra-tumoral susceptibility signals (ITSS), apparent diffusion coefficient (ADC) values, and contrast-enhancing tumor volumes were tested for correlation with response to treatment, progression-free survival (PFS), and overall survival (OS). Response at first follow-up was assessed according to Response Assessment in Neuro-Oncology (RANO) criteria. RESULTS: 8/20 patients showed stable disease at first follow-up. rCBVmax values of the primary glioblastoma (before surgery) significantly correlated to treatment response; specifically, patients with stable disease displayed higher rCBVmax compared to progressive disease (p = 0.04, 2-group t test). Moreover, patients with stable disease showed longer PFS (p = 0.02, 2-group t test) and OS (p = 0.04, 2-group t test). ITSS, ADC values, and contrast-enhancing tumor volumes showed no correlation with treatment response, PFS nor OS. CONCLUSION: Our results suggest that rCBVmax of the glioblastoma at diagnosis could serve as a non-invasive biomarker of treatment response to regorafenib in patients with rGB.

Diagnostic performance of perfusion-weighted imaging combined with serum MMP-2 and -9 levels in tumor recurrence after postoperative concomitant chemoradiotherapy of glioblastoma.

OBJECTIVE: To evaluate diagnostic accuracy of dynamic susceptibility contrast- perfusion weighted imaging (DSC-PWI) combined with serum MMP-2 and -9 levels in differentiating recurrent glioblastoma (GBM). METHODS: We enrolled a total of 220 GBM patients, including recurrent cases (n = 150) and non-recurrent cases (n = 70) after postoperative concomitant chemoradiotherapy. All patients performed preoperative and follow-up DSC-PWI, and two parameters [normalized cerebral blood volume (nCBV) and cerebral blood flow (nCBF)] were obtained. Preoperative serum levels of MMP-2 and MMP-9 were detected using ELISA. The diagnostic performance was evaluated by analyzing receiver operating characteristic (ROC) and area under the curve (AUC). RESULTS: At baseline, the recurrence patients had higher nCBF and nCBV than the non-recurrence patients, accompanying by the increased MMP-2 and MMP-9 levels in serum. Serum MMP-2 level were positively associated with MMP-9 in recurrent patients. In patients classified as recurrence, both MMP-9 and MMP-2 in serum had a significant correlation with nCBV and nCBF. A sensitivity and specificity of nCBF for recurrence vs. non-recurrence were 94.29% and 63.33%, respectively. nCBV also could provide high discrimination between recurrence and non-recurrence patients (sensitivity: 84.29%, specificity: 62.67%, AUC: 0.821). In ROC analyses, both MMP-2 and MMP-9 distinguished recurrence from non-recurrence with AUC values of 0.883 and 0.900, respectively. Finally, the combination of DSC-PWI parameters (nCBF and nCBV) and serum MMP-2 and -9 levels showed much better discrimination capacity between recurrence and non-recurrence patients with a sensitivity of 92.86%, specificity of 79.33% and AUC of 0.899. CONCLUSION: The combination of DSC-PWI parameters together with serum MMP-2 and -9 levels offered an attractive approach to noninvasively distinguish recurrence after postoperative radiotherapy of GBM.

Dynamic susceptibility MR perfusion imaging of the brain: not a question of contrast agent molarity.

PURPOSE: Dynamic susceptibility contrast (DSC) perfusion-weighted MR imaging (PWI) is increasingly used in clinical neuroimaging for a range of conditions. More highly concentrated GBCAs (e.g., gadobutrol) are often preferred for DSC imaging because it is thought that more Gd is present in the volume of interest during first pass for a given equivalent injection rate. However, faster injection of a less viscous GBCA (e.g., gadoteridol) might generate a more compact and narrower contrast bolus thus obviating any perceived benefit of higher Gd concentration. This preliminary study aimed to analyze and compare DSC examinations in the healthy brain hemisphere of patients with brain tumors using gadobutrol and gadoteridol administered at injection rates of 4 and 6 mL/s. METHODS: Thirty-nine brain tumor patients studied with DSC-PWI were evaluated. A simplified gamma-variate model function was applied to calculate the mean peak, area under the curve (AUC), and full-width at half-maximum (FHWM) of concentration-time curves derived from ΔR2* signals at four different regions-of-interest (ROIs). Qualitative assessment of the derived CBV maps was also performed independently by 2 neuroradiologists. RESULTS: No qualitative or quantitative differences between the two GBCAs were observed when administered at a flow rate of 4 mL/s. At a flow rate of 6 mL/s, gadoteridol showed lower FWHM values. CONCLUSION: Gadobutrol and gadoteridol are equivalent for clinical assessment of qualitative CBV maps and quantitative perfusion parameters (FHWM) at a flow rate of 4 mL/s. At 6 mL/s, gadoteridol produces a narrower bolus shape and potentially improves quantitative assessment of perfusion parameters.

Grading of IDH-mutant astrocytoma using diffusion, susceptibility and perfusion-weighted imaging.

BACKGROUND: The accurate grading of IDH-mutant astrocytoma is essential to make therapeutic strategies and assess the prognosis of patients. The purpose of this study was to investigate the usefulness of DWI, SWI and DSC-PWI in grading IDH-mutant astrocytoma. METHODS: One hundred and seven patients with IDH-mutant astrocytoma who underwent DWI, SWI and DSC-PWI were retrospectively reviewed. Minimum apparent diffusion coefficient (ADCmin), intratumoral susceptibility signal intensity(ITSS) and maximum relative cerebral blood volume (rCBVmax) values were assessed. ADCmin, ITSS and rCBVmax values were compared between grade 2 vs. grade 3, grade 3 vs. grade 4 and grade 2 + 3 vs. grade 4 tumors. Logistic regression, tenfold cross-validation,and receiver operating characteristic (ROC) curve analyses were used to assess their diagnostic performances. RESULTS: Grade 4 IDH-mutant astrocytomas showed significantly lower ADCmin and higher rCBVmax as compared to grade 3 tumors (adjusted P < 0.001). IDH-mutant grade 3 astrocytomas showed significantly lower ITSS levels as compared with grade 4 tumors (adjusted P < 0.001). ITSS levels between IDH-mutant grade 2 and grade 3 astrocytomas were significantly different (adjusted P = 0.002). Combined the ADCmin, ITSS and rCBVmax resulted in the highest AUC for differentiation grade 2 and grade 3 tumors from grade 4 tumors. CONCLUSION: ADCmin, rCBVmax and ITSS can be used for grading the IDH-mutant astrocytomas. The combination of ADCmin, ITSS and rCBVmax could improve the diagnostic performance in grading of IDH-mutant astrocytoma.

The impact of racial identity and school composition on affirmative action attitudes of African American college students.

Affirmative Action remains a controversial policy that incites a variety of reactions. Some believe it's an unjust policy that discriminates against applicants, while others view it as a policy aimed at fighting against past inequalities and discrimination. Little is known about African American endorsement of the policy. Two hundred and seven Black students from a predominantly White institution (PWI) and a historically Black university (HBCU) participated in the current study to examine the impact of racial identity on affirmative action attitudes (AA). Results indicated that school type and race centrality significantly predicted AA attitudes. Students who attended a HBCU were less likely to endorse AA compared to students at the PWI and those higher in race centrality were more likely to endorse AA. This study is one of the first to investigate the impact of the educational environment on the affirmative action attitudes of African Americans.

Penumbra quantification from MR SWI-DWI mismatch and its comparison with MR ASL PWI-DWI mismatch in patients with acute ischemic stroke.

In acute-ischemic-stroke patients, penumbra assessment plays a significant role in treatment outcome. MR perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch ratio can provide penumbra assessment. Recently reported studies have shown the potential of susceptibility-weighted imaging (SWI) in the qualitative assessment of penumbra. We hypothesize that quantitative penumbra assessment using SWI-DWI can provide an alternative to the PWI-DWI approach and this can also reduce the overall scan-time. The purpose of the current study was to develop a framework for accurate quantitative assessment of penumbra using SWI-DWI and its validation with PWI-DWI-based quantification. In the current study, the arterial-spin-labelling (ASL) technique has been used for PWI. This retrospective study included 25 acute-ischemic-stroke patients presenting within 24 hours of the last noted baseline condition of stroke onset. Eleven patients also had follow-up MRI within 48 hours. MRI acquisition comprised DWI, SWI, pseudo-continuous-ASL (pCASL), FLAIR and non-contrast-angiography sequences. A framework was developed for the enhancement of prominent hypo-intense vein signs followed by automatic segmentation of the SWI penumbra ROI. Apparent-diffusion-coefficient (ADC) maps and cerebral-blood-flow (CBF) maps were computed. The infarct core ROI from the ADC map and the ASL penumbra ROI from CBF maps were segmented semiautomatically. The infarct core volume, SWI penumbra volume (SPV) and pCASL penumbra volume were computed and used to calculate mismatch ratios MRSWIADC and MRCBFADC . The Dice coefficient between the SWI penumbra ROI and ASL penumbra ROI was 0.96 ± 0.07. MRSWIADC correlated well (r = 0.90, p < 0.05) with MRCBFADC , which validates the hypothesis of accurate penumbra assessment using the SWI-DWI mismatch ratio. Moreover, a significant association between high SPV and the presence of vessel occlusion in the MR angiogram was observed. Follow-up data showed salvation of penumbra tissue (location and volumes predicted by proposed framework) by treatments. Additionally, functional-outcome analysis revealed 93.3% of patients with MRSWIADC > 1 benefitted from revascularization therapy. Overall, the proposed automated quantitative assessment of penumbra using the SWI-DWI mismatch ratio performs equivalently to the ASL PWI-DWI mismatch ratio. This approach provides an alternative to the perfusion sequence required for penumbra assessment, which can reduce scan time by 17% for the protocol without a perfusion sequence.

Sequential implementation of DSC-MR perfusion and dynamic [18F]FET PET allows efficient differentiation of glioma progression from treatment-related changes.

PURPOSE: Perfusion-weighted MRI (PWI) and O-(2-[18F]fluoroethyl-)-l-tyrosine ([18F]FET) PET are both applied to discriminate tumor progression (TP) from treatment-related changes (TRC) in patients with suspected recurrent glioma. While the combination of both methods has been reported to improve the diagnostic accuracy, the performance of a sequential implementation has not been further investigated. Therefore, we retrospectively analyzed the diagnostic value of consecutive PWI and [18F]FET PET. METHODS: We evaluated 104 patients with WHO grade II-IV glioma and suspected TP on conventional MRI using PWI and dynamic [18F]FET PET. Leakage corrected maximum relative cerebral blood volumes (rCBVmax) were obtained from dynamic susceptibility contrast PWI. Furthermore, we calculated static (i.e., maximum tumor to brain ratios; TBRmax) and dynamic [18F]FET PET parameters (i.e., Slope). Definitive diagnoses were based on histopathology (n = 42) or clinico-radiological follow-up (n = 62). The diagnostic performance of PWI and [18F]FET PET parameters to differentiate TP from TRC was evaluated by analyzing receiver operating characteristic and area under the curve (AUC). RESULTS: Across all patients, the differentiation of TP from TRC using rCBVmax or [18F]FET PET parameters was moderate (AUC = 0.69-0.75; p < 0.01). A rCBVmax cutoff > 2.85 had a positive predictive value for TP of 100%, enabling a correct TP diagnosis in 44 patients. In the remaining 60 patients, combined static and dynamic [18F]FET PET parameters (TBRmax, Slope) correctly discriminated TP and TRC in a significant 78% of patients, increasing the overall accuracy to 87%. A subgroup analysis of isocitrate dehydrogenase (IDH) mutant tumors indicated a superior performance of PWI to [18F]FET PET (AUC = 0.8/< 0.62, p < 0.01/≥ 0.3). CONCLUSION: While marked hyperperfusion on PWI indicated TP, [18F]FET PET proved beneficial to discriminate TP from TRC when PWI remained inconclusive. Thus, our results highlight the clinical value of sequential use of PWI and [18F]FET PET, allowing an economical use of diagnostic methods. The impact of an IDH mutation needs further investigation.

Comparison of MR-PWI quantitative and semi-quantitative parameters for the evaluation of liver fibrosis.

BACKGROUND: To evaluate different stages of liver fibrosis in cynomolgus monkeys by comparing magnetic resonance-perfusion weighted imaging (MR-PWI) quantitative and semi-quantitative parameters, and confirm the best detection indicators for diagnosis of liver fibrosis. METHODS: A liver fibrosis model of different stages (S0-S4) was established in cynomolgus monkeys. The changes in MR-PWI quantitative and semi-quantitative parameters with the progression of liver fibrosis were investigated. RESULTS: MR-PWI quantitative parameters gradually decreased with the progression of liver fibrosis. Hepatic arterial perfusion index (HPI) was found to increase with the progression of liver fibrosis and significant differences of HPI between each group were observed. There was a highly positive correlation between HPI and the stages of liver fibrosis. Receiver operating characteristic (ROC) curve analysis showed that HPI had the highest efficacy of the MR-PWI quantitative parameters for the diagnosis of liver fibrosis. The MR-PW semi-quantitative parameters gradually reduced with the progression of liver fibrosis, and the differences were statistically significant between stages S3-S4 and S0-S2. Time to peak (TPP) gradually extended and showed a positive correlation with the stages of liver fibrosis. TTP had the highest efficacy of the semi-quantitative parameters for diagnosis of liver fibrosis. CONCLUSIONS: Both the MR-PWI quantitative and semi-quantitative parameters of the liver fibrosis model in cynomolgus monkeys varied at different stages of liver fibrosis, and HPI and TTP were the best detection indices for quantitative and semi-quantitative evaluation of liver fibrosis, respectively.

Clinical report of a brain magnetic resonance imaging finding in Noonan syndrome.

Noonan syndrome (NS) is an autosomal dominant disease caused by aberrant up-regulated signaling through RAS GTPase. It is characterized by facial dysmorphisms, short stature, congenital heart defects, malformations of rib cage bones, bleeding problems, learning difficulties, or mild intellectual disability. Additional intracranial findings in NS patients include tumors, midline anomalies, and malformations of cortical development. In this report, we present the case of a young female patient, with a known diagnosis of Noonan syndrome that in complete well being developed two brain lesions, in the right nucleus pallidus and in the left cerebellar hemisphere respectively, whose location and signal on MRI looked similar to neurofibromatosis type 1 unidentified bright objects (UBOs), and whose spectroscopic characteristics excluded neoplasms.

Role of neuroimaging before reperfusion therapy. Part 1 - IV thrombolysis - Review.

This review paper summarises the yield of the different imaging modalities in the evaluation of patients for IV thrombolysis. Non-contrast CT and CTA or brain MRI combined with MRA are the recommended sequences for the evaluation of patients within the 4.5 hours time window. Multimodal MRI (DWI/PWI), and more recently, CT perfusion, offer reliable surrogate of salvageable penumbra, the target mismatch, which is now currently used as selection criteria for revascularisation treatment in an extended time window. Those sequences may also help the physician for the management of other limited cases when the diagnosis of acute ischemic stroke is difficult. Another approach the DWI/FLAIR mismatch has been proposed to identify among wake-up stroke patients those who have been experiencing an acute ischemic stroke evolving from less than 4.5hrs. Other biomarkers, such as the clot imaging on MRI and CT, help to predict the recanalisation rate after IVT, while the impact of the presence microbleeds on MRI remains to be determined.

Comparison of Conventional, Diffusion, and Perfusion MRI Between Low-Grade and Anaplastic Extraventricular Ependymoma.

OBJECTIVE. The purpose of this study was to investigate and compare conventional MRI, DWI, and dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI) characteristics between low-grade and anaplastic extraventricular ependymomas. MATERIALS AND METHODS. Twenty-six patients with extraventricular ependymomas (19 anaplastic and seven low-grade) who underwent preoperative MRI were enrolled in this retrospective study. Conventional MRI and DWI were performed in all patients; DSCPWI was performed in 15 patients (11 with anaplastic ependymoma and four with low-grade ependymoma). Demographics, conventional MRI features, minimum relative apparent diffusion coefficient (rADCmin), and maximum relative cerebral blood volume (rCBVmax) of the low-grade and anaplastic ependymomas were compared. Diagnostic performance with optimal cutoff values was determined. RESULTS. Anaplastic extraventricular ependymomas were more likely to be located in the superficial supratentorial cerebral hemisphere (p = 0.026) and to present with pial and cortical involvement (p = 0.028 and 0.013, respectively) and necrotic degeneration (p = 0.014). The mean rADCmin ± SD of anaplastic ependymoma was significantly lower than that of low-grade ependymoma (0.8 ± 0.2 vs 1.2 ± 0.3, p = 0.002). The mean rCBVmax of anaplastic ependymoma was significantly higher than that of low-grade ependymoma (15.7 ± 5.3 vs 9.0 ± 4.4, p = 0.042). The cutoff values in grading extraventricular ependymoma were 1.02 for rADCmin and 10.43 for rCBVmax. Combining conventional MRI, DWI, and DSC-PWI allowed the best differentiation of low-grade and anaplastic ependymoma (AUC = 1.00). CONCLUSION. Conventional MRI, DWI, and DSC-PWI techniques may aid in assessing and grading extraventricular ependymomas.

The influence of semantic associations on sentence production in schizophrenia: an fMRI study.

One of the most prominent symptoms of schizophrenia is thought disorder, which manifests itself in language production difficulties. In patients with thought disorders the associations are loosened and sentence production is impaired. The determining behavioral and neural mechanisms of sentence production are still an important subject of recent research and have not yet been fully understood. The aim of the current study was to examine the influence of associative relations and distractor modalities on sentence production in healthy participants and participants with schizophrenia. Therefore, reaction times and neural activation of 12 healthy subjects and 13 subjects with schizophrenia were compared in an adapted picture word interference paradigm (PWI). No significant group differences were found, neither on the behavioral nor on the neural level. On the behavioral level, for the entire group incremental sentence processing was found, i.e. processing of the second noun only starts after the first noun was processed. At the neural level, activation was discovered in the bilateral caudate nuclei and the cerebellum. Those activations could be related to response enhancement and suppression as well as to the modulation of cognitive processes.

MRI perfusion analysis using freeware, standard imaging software.

BACKGROUND: Perfusion-weighted imaging is only scarcely used in veterinary medicine. The exact reasons are unclear. One reason might be the typically high costs of the software packages for image analysis. In addition, a great variability concerning available programs makes it hard to compare results between different studies. Moreover, these algorithms are tuned for their usage in human medicine and often difficult to adapt to veterinary studies. In order to address these issues, our aim is to deliver a free open source package for calculating quantitative perfusion parameters. We develop an "R package" calculating mean transit time, cerebral blood flow and cerebral blood volume from data obtained with freely imaging software (OsiriX Light®). We hope that the free availability, in combination with the fact that the underlying algorithm is open and adaptable, makes it easier for scientists in veterinary medicine to use, compare and adapt perfusion-weighted imaging analysis. In order to demonstrate the usage of our software package, we reviewed previously acquired perfusion-weighted images from a group of eight purpose-breed healthy beagle dogs and twelve client-owned dogs with idiopathic epilepsy. In order to obtain the data needed for our algorithm, the following steps were performed: First, regions of interest (ROI) were drawn around different, previously reported, brain regions and the middle cerebral artery. Second, a ROI enhancement curve was generated for each ROI using a freely available PlugIn. Third, the signal intensity curves were exported as a comma-separated-value file. These files constitute the input to our software package, which then calculates the PWI parameters. RESULTS: We used our software package to re-assess perfusion weighted images from two previous studies. The clinical results were similar, showing a significant increase in the mean transit time and a significant decrease in cerebral blood flow for diseased dogs. CONCLUSION: We provide an "R package" for computing the main perfusion parameters from measurements taken with standard imaging software and describe in detail how to obtain these measurements. We hope that our contribution enables users in veterinary medicine to easily obtain perfusion parameters using standard Open Source software in a standard, adaptable and comparable way.

Investigating dynamic susceptibility contrast-enhanced perfusion-weighted magnetic resonance imaging in posterior fossa tumors: differences and similarities with supratentorial tumors.

PURPOSE: To assess the accuracy of dynamic susceptibility contrast-enhanced perfusion-weighted magnetic resonance imaging in glioma grading and brain tumor characterization of infratentorial tumors, and to investigate differences from supratentorial tumors. METHODS: This retrospective study, approved by the institutional review board, included 246 patients with brain tumors (184 supratentorial, 62 infratentorial), grouped by tumor type: high-grade gliomas (HGG), low-grade gliomas (LGG), metastases (Met), and primary central nervous system lymphoma (PCNSL). Relative cerebral blood volume (rCBV) and mean percentage of signal recovery (PSR) were calculated. For statistical analyses, lesions were grouped by location and histology. Differences were tested with Mann-Whitney U tests. From ROC curves, we calculated accuracy, sensitivity, specificity, PPV, and NPV, for rCBV and PSR. RESULTS: For infratentorial tumors, rCBV was highly accurate in differentiating HGG from LGG (AUC = 0.938). Mean PSR showed high accuracy in differentiating PCNSL and HGG from Met (AUC = 0.978 and AUC = 0.881, respectively). Infratentorial and supratentorial tumors had similarly high rCBV in HGG, high mean PSR in PCNSL, and low mean PSR in Met. The main differences were the optimum threshold rCBV values (3.04 for supratentorial, 1.77 for infratentorial tumors) and the mean PSR, which was significantly higher in LGG than in HGG in supratentorial (p = 0.035), but not infratentorial gliomas. Using infratentorial rCBV threshold values for supratentorial tumors decreased the sensitivity and specificity. CONCLUSION: rCBV and mean PSR were useful in grading and differentiating infratentorial tumors. Proper cutoff values were important in the accuracy of perfusion-weighted imaging in posterior fossa tumors.

Fully Automated and Real-Time Volumetric Measurement of Infarct Core and Penumbra in Diffusion- and Perfusion-Weighted MRI of Patients with Hyper-Acute Stroke.

Multimodal magnetic resonance imaging (MRI) has emerged as a promising tool for diagnosing ischemic stroke and for determining treatment strategies in the acute phase. The detection and quantification of the penumbra and the infarct core regions aid the assessment of the potential risks and benefits of thrombolysis by providing information on salvageable tissue or ischemic lesion age. In this study, we proposed a fully automated and real-time algorithm to compute parameter maps of perfusion-weighted images (PWIs) and to identify an infarct core from diffusion-weighted images (DWIs). DWI and PWI were obtained using a 1.5 Tesla MRI scanner for 15 patients with acute ischemic stroke. Parameter maps of PWI were computed using restricted gamma-variate curve fitting and Fourier-based deconvolution. The ischemic penumbra was identified using time-to-maximum (Tmax) > 6 s as the mutual optimal threshold, while the infarct core was segmented using an adaptive thresholding on DWI. When the penumbra on PWI was compared with that generated using commercial software Pearson's linear correlation coefficient between penumbra volumes was 0.601 (p = 0.030), and the Dice coefficient was 0.51 ± 0.15. The infarct core on DWI was compared with the manually segmented gold standard. Dice coefficient between the manually drawn and automated segmented infarct cores was 0.62 ± 0.18. The processing times for PWI and DWI were 222.9 ± 16.4 and 53.4 ± 4.8 s, respectively. In conclusion, we demonstrate a fully automated and real-time algorithm to segment the penumbra and the infarct core regions based on PWI and DWI.

Heterogeneity of glioblastoma with gliomatosis cerebri growth pattern on diffusion and perfusion MRI.

BACKGROUND AND PURPOSE: Gliomatosis cerebri (GC) is a rare growth pattern of glioblastoma whose diffuse nature is reflected by unspecific, relatively uniform findings on conventional MRI. In the present study we sought to evaluate the additional value of diffusion (DWI) and perfusion weighted (PWI) MRI for a more detailed characterization. METHODS: We analyzed the MRI findings in patients with histologically proven glioblastoma with GC growth pattern with a specific emphasis on T2 lesion pattern, volume, relative apparent diffusion coefficient (rACD), and relative cerebral blood volume (rCBV) and compared these to age-/gender-matched patients with localized glioblastoma. RESULTS: Overall, 16 patients (median age 59.5 years, 4 male) were included in the study. Of these, 8 patients had a glioblastoma with GC growth pattern, and 8 a classical localized growth pattern. While the median rADC (1.27 [IQR 1.12-1.41]) within the T2 lesion was significant lower in glioblastoma with GC growth pattern compared to localized glioblastoma (1.74 [IQR 1.45-1.96]; p = 0.003), the median T2 lesion volume and rCBV within the T2 lesion did not differ significantly. Furthermore, six patients with glioblastoma with GC growth pattern showed focal areas with significantly reduced rADC (p = 0.043), and/or increased rCBV (p = 0.028). CONCLUSIONS: Lower rADC in glioblastoma with GC growth pattern might reflect the diffuse tumor cell infiltration whereas focal areas with decreased rADC and/or increased rCBV probably indicate high tumor cell density and/or abnormal tumor vessels which may be useful for biopsy guidance.

Diagnostic accuracy of intraoperative perfusion-weighted MRI and 5-aminolevulinic acid in relation to contrast-enhanced intraoperative MRI and 11C-methionine positron emission tomography in resection of glioblastoma: a prospective study.

The aim of our study was to compare depicted pre-, intra-, and postoperative tumor volume of met-PET, perfusion-weighed MRI (PWI), and Gd-DTPA MRI. Further, to assess their sensitivity and specificity in correlation with histopathological specimen. Inclusion criteria of the prospective study were histological confirmed glioblastoma (GB), age > 18, and eligible for gross total resection (GTR). Met-PET was performed before and after surgery. Gd-DTPA MRI and PWI were performed before, during, and after surgery. A combined 5-aminolevulinic acid (5-ALA) and iMRI-guided surgery was performed. Volumetric analysis was evaluated for all imaging modalities except for 5-ALA. A total of 59 navigated biopsies were taken. Sensitivity and specificity were calculated for Gd-DTPA MRI, PWI, met-PET, and 5-ALA according to the histology of specimen. Met-PET depicted significantly larger tumor volume before surgery (p = 0.01) compared to PWI and Gd-DTPI MRI. We found no significant difference in tumor volume between met-PET and PWI after surgery (p = 0.059). Both PWI and met-PET showed significantly larger tumor volume after surgery when compared to Gd-DTPA (p = 0.018 and p = 0.003, respectively). Intraoperative PWI reading was impaired in 33.3% due to artifacts. Met-PET showed the highest sensitivity for detection of GB with 95%. The lowest sensitivity was found with Gd-DTPA MRI (50%), while 5-ALA and intraoperative PWI showed similar results (69 and 67%). Met-Pet is the imaging modality with the highest sensitivity to detect a residual tumor in GB. Intraoperative PWI seems to have a synergistic effect to Gd-DTPA and 5-ALA. However, its value may be limited by artifacts. Both pre- and intraoperative PWI cannot substitute met-PET in tumor detection.