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Objective:Central nervous system involvement in patients with coronavirus disease-2019 (COVID-19) is associated with increased morbidity and mortality. The assessment of neurological symptoms in patients with critical illnesses, who are mechanically ventilated under deep sedation is challenging, which means doctors could be unaware of such symptoms until patients reach the weaning stage. Thus, this study aimed to identify potential prognostic predictors for COVID-19-related impaired consciousness in patients with critical illnesses.Materials and Methods:This retrospective, multicenter, and observational cohort study was conducted among patients with COVID-19 who were admitted to the intensive care units of five hospitals between March 11, 2020, and September 18, 2020. The patient population was analyzed in two groups-cases with impaired consciousness and cases without impaired consciousness.Results:Patients with impaired consciousness were found to be significantly younger (p=0.001) and to exhibit significantly more laboratory abnormalities, such as high ferritin (p=0.003), C-reactive protein (p=0.001), procalcitonin (p=0.019), and D-dimer (p=0.001) levels. Additionally, pathological magnetic resonance imaging findings were detected in 14 of 29 (48%) patients with impaired consciousness.Conclusion:All patients with severe COVID-19 should be screened for signs of hyperinflammation due to the associated risk of neurological complications. The early detection of at-risk cases and the prompt initiation of specific treatment should result in better disease outcomes.

PURPOSE: The reliability and reproducibility of T2-weighted imaging/fluid-attenuated inversion recovery (T2/FLAIR) mismatch were investigated in the diagnosis of isocitrate dehydrogenase (IDH) mutant astrocytoma between WHO grade II and III diffuse hemispheric gliomas. METHODS: WHO grade II and grade III diffuse hemispheric gliomas (n=133) treated in our institute were included in the study. Pathological findings and molecular markers of the cases were reviewed with the criteria of WHO 2016. The finding of mismatch between T2-weighted and FLAIR images in preoperative magnetic resonance imaging (MRI) of the cases was evaluated by two different radiologists. The readers reviewed MRIs independently, blinded to the histopathologic diagnosis or molecular subset of tumors. The cases were classified as IDH-mutant astrocytoma, oligodendroglioma and IDH-wildtype (IDH-wt) astrocytoma according to molecular and genetic features. RESULTS: T2/FLAIR mismatch positivity was observed in 46 patients (34.6%). T2/FLAIR mismatch positivity was observed in 42 of 75 IDH-mutant astrocytomas (56%) and 4 of 43 oligodendrogliomas (9.30%), while it was not seen among IDH-wt astrocytomas (0/15, 0%). The T2/FLAIR mismatch ratio was significantly different between IDH-mutant astrocytomas (WHO grade II and grade III) and oligodendrogliomas (chi-square, p

Introduction Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is caused by a recessive mutation in the DARS2 gene and can be recognized by specific magnetic resonance imaging patterns. Case report A girl who developed leg tremors at age 4 years was diagnosed at age 17 years with LBSL -after evolution of ataxia and sensory loss. Examination at age 29 revealed mild spastic gait, ataxia, and sensory loss, and she did not require assistance to walk. Conclusion This report illustrates the clinical and magnetic resonance imaging characteristics of a slowly progressive long-term course of childhood-onset LBSL.

OBJECTIVE Gliomas frequently involve the insula both primarily and secondarily by invasion. Despite the high connectivity of the human insula, gliomas do not spread randomly to or from the insula but follow stereotypical anatomical involvement patterns. In the majority of cases, these patterns correspond to the intrinsic connectivity of the limbic system, except for tumors with aggressive biology. On the basis of these observations, the authors hypothesized that these different involvement patterns may be correlated with distinct outcomes and analyzed these correlations in an institutional cohort. METHODS Fifty-nine patients who had undergone surgery for insular diffuse gliomas and had complete demographic, pre- and postoperative imaging, pathology, molecular genetics, and clinical follow-up data were included in the analysis (median age 37 years, range 21–71 years, M/F ratio 1.68). Patients with gliomatosis and those with only minor involvement of the insula were excluded. The presence of T2-hyperintense tumor infiltration was evaluated in 12 anatomical structures. Hierarchical biclustering was used to identify co-involved structures, and the findings were correlated with established functional anatomy knowledge. Overall survival was evaluated using Kaplan-Meier and Cox proportional hazards regression analysis (17 parameters). RESULTS The tumors involved the anterior insula (98.3%), posterior insula (67.8%), temporal operculum (47.5%), amygdala (42.4%), frontal operculum (40.7%), temporal pole (39%), parolfactory area (35.6%), hypothalamus (23.7%), hippocampus (16.9%), thalamus (6.8%), striatum (5.1%), and cingulate gyrus (3.4%). A mean 4.2 ± 2.6 structures were involved. On the basis of hierarchical biclustering, 7 involvement patterns were identified and correlated with cortical functional anatomy (pure insular [11.9%], olfactocentric [15.3%], olfactoopercular [33.9%], operculoinsular [15.3%], striatoinsular [3.4%], translimbic [11.9%], and multifocal [8.5%] patterns). Cox regression identified hippocampal involvement (p = 0.006) and postoperative tumor volume (p = 0.027) as significant negative independent prognosticators of overall survival and extent of resection (p = 0.015) as a significant positive independent prognosticator. CONCLUSIONS The study findings indicate that insular gliomas primarily involve the olfactocentric limbic girdle and that involvement in the hippocampocentric limbic girdle is associated with a worse prognosis.

Background There is a growing interest in noninvasively defining molecular subsets of hemispheric diffuse gliomas based on the isocitrate dehydrogenase (IDH) and telomerase reverse transcriptase gene promoter (TERTp) mutation status, which correspond to distinct tumor entities, and differ in demographics, natural history, treatment response, recurrence, and survival patterns. Purpose To investigate whether metabolite levels detected with short echo time (TE) proton MR spectroscopy (1 H-MRS) at 3T can be used for noninvasive molecular classification of IDH and TERTp mutation-based subsets of gliomas. Study type Retrospective. Subjects In all, 112 hemispheric diffuse gliomas (70 males/42 females, mean age: 42.1 ± 13.9 years). Field strength/sequence Short-TE 1 H-MRS (repetition time (TR) = 2000 msec, TE = 30 msec, number of signal averages = 192) and routine clinical brain tumor MR protocols were acquired at 3T. Assessment 1 H-MRS data were quantified using LCModel software. TERTp and IDH1 or IDH2 (IDH1/2) mutations in the tissue were determined by either minisequencing or Sanger sequencing. Statistical tests Metabolic differences between IDH mutant and IDH wildtype gliomas were assessed by a Mann-Whitney U-test. A Kruskal-Wallis test followed by a Tukey-Kramer test was used to analyze metabolic differences between IDH and TERTp mutational molecular subsets of gliomas. A Spearman rank correlation coefficient was used to assess the correlations of metabolite intensities with the Ki-67 index. Furthermore, machine learning was employed to classify the IDH and TERTp mutational status of gliomas, and the accuracy, sensitivity, and specificity values were estimated. Results Short-TE 1 H-MRS classified the presence of an IDH mutation with 88.39% accuracy, 76.92% sensitivity, and 94.52% specificity, and a TERTp mutation within primary IDH wildtype gliomas with 92.59% accuracy, 83.33% sensitivity, and 95.24% specificity. Data conclusion Short-TE 1 H-MRS could be used to identify molecular subsets of hemispheric diffuse gliomas corresponding to IDH and TERTp mutations. Level of evidence 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1799-1809.

Objective: This study aimed to investigate the correlation between index lesion prostate imaging-reporting and data system (PI-RADS) version-2 score and histopathological outcomes of prostatectomy specimens. Materials and Methods: A total of 78 male patients with prostate cancer (PCa) treated with robot-assisted radical prostatectomy between August 2015 and June 2020 were included in this study. In this cohort, suspicious lesions on multiparametric magnetic resonance imaging (mpMRI) were scored according to PI-RADS version-2 criteria. MpMRI-targeted prostate biopsy was performed for all suspicious lesions with a PI-RADS score of >= 3 followed by systematic prostate biopsy. The relationship between index lesion PI-RADS score and histopathological outcomes of prostatectomy specimens were evaluated statistically. Results: The mean age of the patients was 65.0 +/- 7.0 years. The distribution of PI-RADS scores of 3, 4, and 5 of the index lesions were 6 (7.7\%), 29 (37.2\%), and 43 (55.1\%), respectively. Lower tumor volume and tumor volume ratio were observed in patients with a PI-RADS score of 3 when they were compared with patients with PI-RADS scores of 4 and PI-RADS-5 (p0.05). However, a significant correlation was observed between index lesion PI-RADS score and extracapsular extension (ECE), as well as seminal vesicle invasion (SVI) and pT stage (r=0.327, p=0.004

Gamma knife radiosurgery (GKRS) delivers an unevenly distributed radiation dose to a tumor, with a sharp falloff outside the target. Although the dose inhomogeneity within a tumor is strongly influenced by its shape, routine GKRS dose planning does not account for it. We hypothesized that shape irregularity measures were correlated with treatment planning indices, and might provide insight during treatment planning. The aims of this study were to quantify the shape irregularity measures in vestibular schwannomas, estimate their correlations with core radiosurgical planning measures, and define the most predictive shape feature for dose effectiveness. METHODS: Four dose plan indices, which were the selectivity index (SI), gradient index (GI), efficiency index (EI), and Paddick’s conformity index (PCI) were estimated from the GKRS plans of 234 vestibular schwannomas. All dose plans were prepared using Gamma Plan 10.0 and above and all treatments were delivered using a perfexion/ICON platform. Three-dimensional (3D) tumor models were rendered using 3D Slicer Software from segmented T1-weighted MR images. Sixteen irregularity measures were calculated for each tumor using Radiomics in MATLAB. Spearman correlation coefficients (r) were computed to find associations of the dose plan indices with the irregularity descriptors. The most predictive shape feature for dose efficiency was identified using the least absolute shrinkage and selection operator (Lasso). RESULTS: The shape irregularity measures were negatively correlated with SI, EI, and PCI, and positively correlated with GI. Volumetric index of sphericity (VioS) had the highest correlations with SI (r = 0.63, p= 3.27E-23), GI (r= -0.58, p= 1.10E-19), EI (r = 0.69, p= 0.00), and PCI(r= 0.68, p = 6.73E-28), and Lasso feature selection identified VioS as the most important feature for predicting all dose plan indices. CONCLUSION: VioS provides a numerical quantification of tumor shape irregularity, and it is highly correlated with the GKRS dose planning indices. *indicates co-senior authors

To investigate the correlation of multiparametric magnetic resonance imaging targeted (TBx) and/or systematic prostate biopsy (SBx) in predicting the presence of clinically significant (cs) prostate cancer (PCa) in radical prostatectomy (RP) specimens. Concordance of mpMRI and RP specimen lesions was also investigated in terms of tumor localization and histopathological features.A total of 70 male patients with PCa and treated with robot-assisted RP were included in this study between January 2016 and December 2019. All patients underwent mpMRI-TBx and concomitant SBx. Suspicious lesions on mpMRI were scored according to Prostate Imaging-Reporting and Data System version 2 (PI-RADS) criteria. TBx was performed for all suspicious lesions with a PI-RADS score ≥3.The median age was 67 (43-77) years. Presence of csPCa in prostatectomy specimens was missed by TBx and SBx specimens in 25.4% and 19.4% of the cases, respectively (P.001, for each). Combination of both biopsy (CBx) results improved detection by missing only 4.5% of csPCa (P = .250). International Society of Urologic Pathology grade group concordance with RP specimens were 50%, 54.3% and 67.1% for SBx, TBx, and CBx, respectively. There was a statistically significant correlation in terms of tumor localization and histopathological features between prostatectomy specimens and the first 3 lesions, particularly for the index lesions.CBx improved detection rate of csPCa. We propose TBx of 3 lesions with highest PI-RADS score(s) and a combination with SBx for the highest correlation with prostatectomy histopathology.

Purpose: Histopathological and radiological examination is necessary for the evaluation of tumor types and staging. Histopathologic examination is considered as the gold standard, while the radiological examination is used for preoperative evaluation. The purpose of the present study was to evaluate susceptibility-weighted imaging SWI the in grading of infiltrative glial tumors.Materials and Methods: The SWI sequences in pre-operative magnetic resonance imaging MRI images were retrospectively assessed in a total of 67 patients mean age, 36.7 years; age range, 4–79 years; 29 female, 38 male who were diagnosed with a glial tumor based on histopathological examination. The numbers of punctate intratumoral susceptibility sign ITSS in the SWI sequence in the tumors were determined by two radiologists on a consensus-based approach. Lesions with no ITSS were graded as Grade 0, while those having 1–5, 6–15, >15 ITSS were categorized as Grade 1, Grade 2, and Grade 3, respectively. No susceptibility was classified as ITSS, “non-punctate with blurred margins” and diffuse susceptibility were categorized as >15. ITSS grades were compared to the results of histopathological grading and diagnosis.Results: The sensitivity, specificity, negative predictive value, and positive predictive value of the presence of ITSS regarding differentiating high and low-grade glial tumors were 97.6%, 88%, 95.65%, and 93.18%, respectively.Conclusion: In diffuse glial tumors, while the presence of ITSS is indicative of high-grade tumors, its absence is associated with low-grade tumors. These data suggest that the presence rather than the number of ITSS yields more information on the grade of this type of tumor

Dincer, Alp/0000-0001-9158-8353; Afsar, Nazire/0000-0001-8123-8560; KAYA, DILAVER/0000-0002-7364-171X; Yildirim, Duzgun/0000-0002-5411-229X; Sarikaya, Zeynep Tugce/0000-0002-1352-7667; Dogan, Lerzan/0000-0002-1456-4072; Korkmazer, Bora/0000-0001-7015-365X; Mammadov, Orkhan/0000-0001-7648-2948 WOS:000574262800006 PubMed ID: 32384020 [No abstract available]

Highlights. • Severely ill COVID-19 patients failing to regain consciousness or showing agitation during the ventilation weaning period require thorough neurological assessment. • Brain magnetic resonance imaging and cerebrospinal fluid examination are required to determine the extent of central nervous system involvement. • Neurological involvement during COVID-19 infection can be immune mediated. • Plasmapheresis can be beneficial in COVID-19 patients with autoimmune encephalitis., Severe SARS-CoV-2 (COVID-19) infection has the potential for a high mortality rate. In this paper, we report the results of plasmapheresis treatment in a series of severely ill patients with COVID-19–related autoimmune meningoencephalitis in the Intensive Care Unit ICU.

Advances in preoperative brain magnetic resonance imaging (MRI) have increased our ability to predict tumor pathology (even grade) and to make a proper surgical plan accordingly. Perioperative brain MRI has been shown to increase tumor resection rates in glial and pituitary tumors. Besides, perioperative MRI enables us to reach deep-seated tumor location in a safe trajectory. In this chapter, we present our clinical experience in preoperative and perioperative brain MRI modalities by presenting three cases.

Acute neck pain can have non-vascular and vascular causes. Some patients present with distinct vascular and perivascular changes on imaging at the site of tenderness. This study aimed to evaluate the imaging findings of transient perivascular inflammation of the carotid artery (TIPIC) syndrome with an emphasis on vessel wall imaging using 3‑Tesla (3-T) high-resolution (HR) magnetic resonance imaging (MRI). Clinical data along with diagnostic and follow-up imaging of patients presenting to these hospitals with acute neck pain/tenderness and at least 1 imaging study using color Doppler ultrasound (CDU) and/or MRI including vessel wall imaging from September 2013 through September 2017 were retrospectively evaluated. A total of 15 patients with no other underlying cause of pain, findings meeting the imaging criteria for TIPIC syndrome and clinical recovery (spontaneous or with treatment) were included in the study. The mean patient age was 43.2 years. With CDU and precontrast MRI, perivascular inflammation (PVI) of the involved artery segment was evident in all patients. Contrast enhancement of the adventitia and PVI were noted on postcontrast HR vessel wall MRI in all patients. Of the patients five had co-existing plaques at the site of tenderness. Follow-up imaging demonstrated pronounced regression or complete resolution of the findings. Imaging is useful for the establishment of TIPIC syndrome diagnosis and to rule out other conditions. The use of CDU is usually sufficient for diagnosis and follow-up but in clinically doubtful and complicated cases, vessel wall imaging with HR-MRI is very valuable. Thorough knowledge of this entity among radiologists enables a prompt diagnosis, which accelerates the clinical management.

Aim The central tegmental tract hyperintensities (CTTH) have been found in many different pediatric neurological conditions. There is only scarce data about the value of this radiological phenomenon. In this study we aimed to show the neurological conditions associated with this radiological finding. Materials and methods We performed a retrospective analysis of all pediatric brain MRI’s between 2013 and 2015. After finding those patients with CTTH, we evaluated them in the pediatric neurology clinic. Results There were 41 out of 1464 brain MRI’s with CTTH with 2.8% prevalence. Thirty four patients (23 male, age range 3 months–98 months) were available for evaluation. CTTH were present in mainly younger age group. There were many different neurological conditions associated with CTTH. These included brain tumors, epilepsy, developmental delay, metabolic disorders and genetic syndromes. Conclusion CTTH is found in many different pediatric neurological conditions. Further neuropathological and prospective MRI and clinical studies are needed to better understand this interesting radiological finding.

PURPOSE To test whether the combined use of 4D arterial spin labeling angiography (4D ASL) and contrast-enhanced magnetic resonance angiography (4D CE-MRA) can work as a prospective alternative to digital subtraction angiography (DSA) for the delineation of the arteriovenous malformation (AVM) nidus in stereotactic radiosurgery (SRS) planning. MATERIALS AND METHODS A custom 4D ASL sequence and a proof-of-concept software tool to integrate 4D ASL data to SRS planning were implemented. Ten AVM patients were scanned at 3T. Two observers independently contoured niduses in two separate sessions. Reference niduses were contoured using DSA, 4D ASL, and 4D CE-MRA. Test niduses were contoured using 4D ASL and 4D CE-MRA only. Reference and test niduses from both observers were compared in terms of volume, distance between centers of volumes (dCOV), and the Jaccard index (JI). RESULTS In volume comparisons, excellent intraobserver and interobserver agreements were obtained (intraclass correlation coefficients: 0.99 and 0.98, respectively). Median dCOV, JIs between reference and test niduses were 0.55 mm, 0.78 for Observer 1 and were 0.6 mm, 0.78 for Observer 2. None of the dCOV and JI parameters varied significantly among the delineation methods or the observers (P = 0.84, P = 0.39). CONCLUSION Our preliminary results indicate that reproducibility of the target volumes with high agreement levels is achievable without using DSA. The combined use of high temporal resolution 4D ASL and high spatial resolution and vessel-to-background contrast 4D CE-MRA provided sufficient spatiotemporal angiographic information for the delineation of AVM niduses. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1718-1727.

Telomerase reverse transcriptase promoter (TERTp) mutations in the absence of IDH mutations (TERTp-only) are recently proposed as a characteristic of glioblastoma regardless of the morphological grade. This study aims to analyze metabolic profiles of TERTp-only gliomas using proton magnetic resonance spectroscopy (1H-MRS) and evaluate the effect of metabolite concentrations on progression-free survival (PFS) and overall survival (OS). The patient cohort consisted of 56 TERTp-only gliomas (35M/21F, mean age: 58±10.37 years, 44 glioblastomas (GBM), and 12 lower-grade gliomas with TERTp-mutation but no IDH-mutations). All patients underwent preoperative diagnostic 1H-MRS using a 3T MR scanner with a 32-channel head coil. 1H-MRS was obtained from a manually placed region of interest with no necrosis, edema, and hemorrhage, using a Point Resolved Spectroscopy (PRESS) sequence (TR/TE=2000/30 ms, 1024 points). LCModel spectral fitting program was used for quantification of MR spectroscopic peak concentrations of 17 metabolites. The patients were divided into two groups using median values of the metabolite intensities, and Kaplan-Meier survival analysis followed by a log-rank test was used to determine the effects of metabolite concentrations on OS and PFS. Median PFS and OS of TERTp-only gliomas were 11 and 17 months, respectively. TERTp-only LGG patients had longer OS and PFS than TERTp-only GBM patients (p=0.022 for OS and p=0.018 for PFS). Significantly shorter OS and PFS were identified in TERTp-only gliomas, who had higher GSH/tCr (p=0.011 for OS and p=0.004 for PFS) and higher Lac/tCr (p=0.014 for OS and p=0.012 for PFS). Lactate is a marker of necrosis and a sign of malignancy. On the other hand, both tCr and GSH were lower, which resulted in higher GSH/tCr, in TERTp-only GBM. The results of this study indicate that high Lac/tCr and GSH/tCr might be indicators of poor prognosis in TERTp-only gliomas. This study has been supported by TUBITAK 1003 grant 216S432.

IDH mutation, a key factor in predicting glioma prognosis, alters the levels of some metabolites in brain, including 2-hydroxyglutarate (2HG), glutamine (Gln), and glutathione (GSH). While proton MR spectroscopy (1H-MRS) enables in-vivo detection of these metabolites, liquid chromatography-mass spectrometry (LC-MS/MS) is a sensitive in-vitro method to measure absolute metabolite concentrations. This study aims to examine the correlation of metabolic concentrations measured using 1H-MRS and LC-MS/MS in gliomas, and to detect IDH mutation with machine learning based on 1H-MRS and LC-MS/MS metabolic intensities. The patient cohort included 178 glioma patients (111M/67F, mean age:44.09±13.95 years, 100 IDH-mut, 78 IDH-wt). The patients were scanned pre-surgery by a 3T MR scanner with a 32-channel head coil. 1H-MRS was obtained from a manually placed region of interest with no necrosis, edema, and hemorrhage, using a Point Resolved Spectroscopy (PRESS) sequence (TR/TE=2000/30ms). LCModel software was used for quantification of eighteen metabolites of 1H-MRS data. Metabolite concentrations including creatine (Cr), choline (Cho), Gln, glutamate (Glu), gamma-aminobutyric acid (GABA), N-acetyl aspartate (NAA), myo-inositol (mIns), 2HG, and lactate (Lac) were also determined with LC-MS/MS for surgical specimen of the same patients. Spearman correlation coefficients were calculated between the metabolite concentrations measured with 1H-MRS and LC-MS/MS. Additionally, machine-learning algorithms were used to detect IDH mutation in gliomas based on metabolite concentrations obtained with 1H-MRS and LC-MS/MS. Consequently, there were statistically significant correlations between 1H-MRS and LC-MS/MS results for 2HG (p=0.036), Cr (p=0.009), mIns (p

Background and purpose: In sedated pediatric brains, 2D-FLAIR causes increased signal intensity of the cerebrospinal fluid (CSF) leading to false-positive diagnoses. Our aim is to determine whether increased CSF signal intensity is observed on 3D-FLAIR images. Methods: In this institutional review board-approved study, a 2-year retrospective analysis of our MRI database was conducted which revealed 48 sedated pediatric patients with normal cranial MRI findings and 3D-FLAIR sequence. One adult volunteer was imaged before and after O2 inhalation with 2D and 3D-FLAIR sequences. The hyperintensity in the subarachnoid spaces and basal cisterns were quantified as follows: 0: artifact free; 1: homogeneous minimal CSF signal; 2: abnormal CSF signal. Inter-observer agreement was assessed with kappa agreement analysis. Results: Grade 0 and grade 1 signals were observed at inferior to Liliequist membrane (LLQ) in 48/48 and 0/48 cases; prepontine cistern 47/48 and 1/48; superior to LLQ 26/48 and 22/48; 4th ventricle 16/48 and 32/48; 3rd ventricle 34/48 and 14/48; lateral ventricle 3/48 and 45/48; subarachnoid space 36/48 and 12/48, respectively. No patients showed grade 2 signal. Inter-observer agreement was 0.81–1. In the volunteer, after O2 inhalation, grade 2 signal intensity was evident on 2D-FLAIR however; 3D-FLAIR did not show any signal increase. Conclusions: In sedated pediatric brains, 3D-FLAIR suppresses CSF signal, and enables reliable assessment free from CSF artifacts.

Oral appliances are considered as an effective alternative of CPAP devices in the treatment of OSAS. The essential techniques to evaluate the efficacy of a novel oral appliance are MRI image segmentation of upper airway structures and polysomnographic variables. The aim of this study is to introduce a novel mouthpiece device for the treatment of OSAS patients and to evaluate its efficacy. The proposed mouthpiece device design increases intraluminal pressure while reshaping the lower jaw and tongue position during oral breathing. MRI images of upper airway for each patient were taken with and without the mouthpiece device. The oropharyngeal volumes of the participants have been reconstructed as 3D models. Afterwards, each patient attended the sleep laboratory on two nights (with and without the proposed device) for full diagnostic polysomnography. The use of proposed device enlarged the oropharynx volume 75% on average while reducing the respiratory disturbance index by 60% on average. On the other hand, the polysomnographic variables have been significantly improved by the use of novel mouthpiece device The clinical results show that the proposed mouthpiece design offers a promising alternative for OSAS patients.

Diagnosis of cortical vein thrombosis (CVT) on the basis of clot hyperintensity on diffusion-weighted imaging (DWI) has been reported as limited. Our aim was to evaluate different DWI findings of CVT either in isolated form or in combination with sinus thrombosis. In this review-board-approved study, patients with the diagnosis of CVT on magnetic resonance venography (MRV) between 2004 and 2011 were evaluated, and 13 patients with 26 CVT (3 isolated and 23 combined CVT) sites were recruited. The evaluated DWI findings were as follows: (1) the hyperintense clot signal (CS) itself, and (2) clot susceptibility signal (CSS) that appears next to the CVT. Two blinded radiologists evaluated the data. Kappa (κ) statistics was applied for interobserver agreement. Both readers reported CS within the vascular clot itself in 6 of 26 (23 %) CVT sites on DWI. CSS was reported in 16 of 26 (61.5 %) CVT sites by reader 1, and in 14 of 26 (54 %) of the CVT sites by reader 2. At four CVT sites with thrombosed veins on MRV, both readers reported no DWI findings. When both CS and CSS were evaluated together, reader 1 reported a positive DWI finding in 22 of 26 (84 %) of the CVT sites, and reader 2 reported in 20 of 26 (79 %) of the sites. κ Statistics showed a very good agreement (κ: 0.87). Besides the hyperintense CS, with additional evaluation of the presence of CSS, DWI can provide an additional clue in CVT patients and may suggest its diagnosis, which is important in clinically unsuspected patients.

Object The goal of surgery in high-grade gliomas is to maximize the resection of contrast-enhancing tumor without causing additional neurological deficits. Intraoperative MRI improves surgical results. However, when using contrast material intraoperatively, it may be difficult to differentiate between surgically induced enhancement and residual tumor. The purpose of this study was to assess the usefulness of intraoperative dynamic contrast-enhanced T1-weighted MRI to guide this differential diagnosis and test it against tissue histopathology. Methods Preoperative and intraoperative dynamic contrast-enhanced MRI was performed in 21 patients with histopathologically confirmed WHO Grade IV gliomas using intraoperative 3-T MRI. Standardized regions of interest (ROIs) were placed manually at 2 separate contrast-enhancing areas at the resection border for each patient. Time-intensity curves (TICs) were generated for each ROI. All ROIs were biopsied and the TIC types were compared with histopathological results. Pharmacokinetic modeling was performed in the last 10 patients to confirm nonparametric TIC analysis findings. Results Of the 42 manually selected ROIs in 21 patients, 25 (59.5%) contained solid tumor tissue and 17 (40.5%) retained the brain parenchymal architecture but contained infiltrating tumor cells. Time-intensity curves generated from residual contrast-enhancing tumor and their preoperative counterparts were comparable and showed a quick and persistently increasing slope (“climbing type”). All 17 TICs obtained from regions that did not contain solid tumor tissue were undulating and low in amplitude, compared with those obtained from residual tumors (“low-amplitude type”). Pharmacokinetic findings using the transfer constant, extravascular extracellular volume fraction, rate constant, and initial area under the curve parameters were significantly different for the tumor mass, nontumoral regions, and surgically induced contrast-enhancing areas. Conclusions Intraoperative dynamic contrast-enhanced MRI provides quick, reproducible, high-quality, and simply interpreted dynamic MR images in the intraoperative setting and can aid in differentiating surgically induced enhancement from residual tumor.

BACKGROUND Although the word “glioblastoma” still denotes a grade-IV pathology, basic molecular studies have clearly indicated that a significant proportion of lower-grade gliomas harbor genetic alterations typical of glioblastomas. Based on these findings cIMPACT-NOW update 3 has defined an entity called the “diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV”. A TERT-promoter mutation is one of these typical molecular markers of glioblastomas. In this study we analyzed IDH-wild type, TERT-mutant diffuse gliomas of different pathological grades to look for differences in demographic, clinical and survival characteristics. MATERIAL AND METHODS 147 adult hemispheric diffuse-gliomas with wild-type IDH1/2 and mutant TERT-promoter (C228T or C250T) were retrospectively analyzed. Primary thalamic, cerebellar brainstem or spinal cases were excluded. 126 (86%), 16(11%) and 5(3%) patients were WHO grade IV, III and II respectively. After surgical treatment or stereotactic biopsy all patients underwent chemoradiation. Median follow-up was 16mo (1–110). Tumors of different grades were compared for age, gender, multifocality, gliomatosis pattern, Ki-67 index, progression-free survival and overall-survival. RESULTS Mean age at presentation for grade II, III and IV were comparable (58.1, 58 and 58.1; ANOVA, p=0.72). There was a slight male predominance in both lower-grades and WHO-grade IV (M:F ratios 1.625 and 1.74). Mean Ki-67 index was significantly higher in higher grades (0.06, 0.14 and 0.25 for grades II, III and IV; ANOVA, p=0.001). Multifocality was comparable (chi-sq, p=1) in lower-grades (3/21; 14.3%) vs. WHO-grade IV (18/126; 14.3%). Gliomatosis pattern was comparable (chi-sq, p=0.095) in lower-grades (2/21; 9.5%) vs. (3/126; 2.3%). Median recurrence free survival (RFS) was 16 months (0–63) in lower-grades and 8months (1–50) in WHO-grade IV. PFS was significantly different between 3 WHO-grades (Log rank, p=0.007) and also between lower-grades and WHO-grade IV (Log rank, p=0.002). Median overall survival was 26 months(2–110) in lower-grades and 15mo(1–91) in WHO-grade IV. OS was significantly different between 3 WHO-grades (Log rank, p=0.014) and also between lower-grades and WHO-grade IV (Log rank, p=0.007). CONCLUSION Increasing pathological grades of hemispheric “IDH-wild type, TERT-mutant diffuse gliomas” have similar demographic and clinical characteristics but incrasing proliferation indices, decrasing progression free survival and shorter overall survival. The findings may be suggesitve of different grades of one common tumor entity.

Objective: Trisomy 8 mosaicism (MT8) is characterized by intracranial, genitourinary and skeletal system anomalies, congenital cardiovascular disorders, deep palmar and plantar creases, and neoplastic and hematological disorders. In the literature, there are only a few antenatal ultrasound (US) and fetal magnetic resonance imaging (MRI) findings reported for MT8. Case: The fetus whose gestational age was 26 weeks and 4 days was referred for fetal MRI due to corpus callosum agenesis suspected in routine US screening. We are presenting the major and minor MRI findings of the fetus in this case report. Conclusion: Fetal MRI can be used in addition to the antenatal ultrasound to evaluate genetic syndromes such as trisomy 8 mosaicism and to identify additional anomalies which cannot be found in the ultrasound screening.

Venous sinus thrombosis is a serious disease and 40 % of survivors develop neurologic sequelae; mortality may be as high as 10 % [1]. In childhood, more than 40 % cerebral venous sinus thromboses occur within the neonatal period, with an incidence of 2.6 per 100,000 children per year [2, 3]. The unique characteristics of fetal superficial and deep venous systems are important for the diagnosis of venous anomalies in utero. The major prenatally diagnosed venous anomalies in utero are the thrombosed dural sinus malformations (tdsM) and Galen vein aneurysms (GVA) [1, 4]. There are a number of case series that define the routine T1-weighted (T1W) and T2-weighted (T2W) magnetic resonance imaging (MrI) features of fetal cerebral venous pathologies [5–11]. However, evaluation of venous anomalies is challenging even in the neonatal period, especially in equivocal cases [2, 12, 13]. With the advent of faster MrI sequences, the application of advanced neuroradiology sequences has increased in the neonatal period. However, fetal application of sequences like diffusion-weighted imaging (dWI), gradient-echo (Gre) T2* imaging, 2d time-offlight MR angiography (TOF MRA), and MR venography (MrV) in the antenatal period has been limited so far. In designing this study, our purpose is to evaluate the antenatally detected cerebral venous pathologies with various MrI sequences.

Acquiring functional near infrared spectroscopy (fNIRS) and functional magnetic resonance-imaging (fMRI) data are usually done asynchronously. In order to correlate these two different modalities’ data, measurements must be performed at the same time. In this study, we have designed a new MR compatible continuous wave intensity based fNIRS device to overcome this problem. For MR compatible fNIRS, we used two LEDs with wavelengths at 660 and 870 nm. There are four photodiodes for light detection. LEDs operated in a sequential multiplexing mode with adjustable "on" time for each LED. Emitted and diffused light was transferred to and from the tissue through 10 m long single mode plastic optical fibers (INDUSTRIAL FIBER OPTICS, INC.). By using fibers, we overcome MR compatibility problems that can be caused by semi-conductors on probe. This MR compatible fNIRS design can provide synchronous measurements with low cost.

The aim of this study was to evaluate the computed tomography (CT) and magnetic resonance imaging findings (MRI) of asymptomatic remote cerebellar hemorrhage (RCH) at the preoperative, early postoperative, and postoperative period. A total of 983 consecutive adult patients who underwent supratentorial craniotomies were included in the study. The ethics committee approved the study. The patient's clinical records and radiological examinations were retrospectively analyzed. All patients had preoperative CT and MRI examinations, immediate postoperative CT, and postoperative MRI within 24 h. The patients with the radiological diagnosis of RCH were followed up to 5 years. Eight asymptomatic RCH cases were recruited. The prevalence of asymptomatic RCH was 0.8% in our series. RCH was unilateral in two patients and bilateral in six patients. The postoperative CT was positive in two cases. The hemorrhage presented on MRI as folial linear hypointensities in six cases. In three cases (including one mixed case), punctate hypointense spots were identified at the superior cerebellar folia. Diffuse hemorrhage in the cerebellar tonsil, subarachnoid hemorrhage, and hemorrhage in the cerebellar vermis and the ventricles were also seen. The MRI findings were stable up to 5 years. The prevalence of asymptomatic RCH is higher than previously reported. Immediate postoperative CT is usually unremarkable; however, MRI demonstrates various hemorrhagic patterns at the cerebellum other than classical "zebra sign". This condition is self-limiting and no further investigation or follow-up study is required. In the proper clinical setting, the awareness of different hemorrhagic patterns in patients with RCH would prevent unnecessary investigations.

The aim of this review is to present the contemporary role of radiology in evaluating pediatric hydrocephalus. Although conventional brain imaging with ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) reveal the degree of ventricular enlargement and often the etiology of the hydrocephalus, the diagnosis and management of hydrocephalus present common problems in pediatric populations.US, usually sufficient to assess and monitor ventricular size, is used most commonly in preterm infants who have germinal matrix hemorrhages and not able to tolerate transport to the radiology department. Although CT can demonstrate gross dilatation of ventricles, in most cases, it will be necessary to more closely define the nature of the obstruction, either functionally or anatomically. MRI is the best imaging modality to provide such functional and anatomic information. However, since identification of obstructive pathologic processes at any level through the cerebrospinal fluid (CSF) pathway in patients with hydrocephalus is of significant importance because it can change the treatment options, avoiding shunt insertion, a more sophisticated MRI approach is needed instead of obtaining a routine cranial MRI. Furthermore, the outcome after neuroendoscopic procedures is clearly related to patient selection under guidance of neuroimaging.Therefore, the article focuses mainly on the effective usage of various MRI sequences in both diagnosis and follow-up of pediatric hydrocephalus, such as 3D CISS, cine PC, TSE, and GRE T2* sequences, to be able to investigate all possible obstructive pathology through the CSF pathway and to assess the efficiency of treatment in a standardized way.

Object The authors describe the first shared-resource, 3-T intraoperative MR (ioMR) imaging system and analyze its impact on low-grade glioma (LGG) resection with an emphasis on the use of intraoperative proton MR spectroscopy. Methods The Acibadem University ioMR imaging facility houses a 3-T Siemens Trio system and consists of interconnected but independent MR imaging and surgical suites. Neurosurgery is performed using regular ferromagnetic equipment, and a patient can be transferred to the ioMR imaging system within 1.5 minutes by using a floating table. The ioMR imaging protocol takes < 10 minutes including the transfer, and the authors obtain very high–resolution T2-weighted MR images without the use of intravenous contrast. Functional sequences are performed when needed. A new 5-pin headrest–head coil combination and floating transfer table were specifically designed for this system. Results Since the facility became operational in June 2004, 56 LGG resections have been performed using ioMR imaging, and > 19,000 outpatient MR imaging procedures have been conducted. First-look MR imaging studies led to further resection attempts in 37.5% of cases as well as a 32.3% increase in the number of gross-total resections. Intraoperative ultrasonography detected 16% of the tumor remnants. Intraoperative proton MR spectroscopy and diffusion weighted MR imaging were used to differentiate residual tumor tissue from peritumoral parenchymal changes. Functional and diffusion tensor MR imaging sequences were used both pre- and postoperatively but not intraoperatively. No infections or other procedure-related complications were encountered. Conclusions This novel, shared-resource, ultrahigh-field, 3-T ioMR imaging system is a cost-effective means of affording a highly capable ioMR imaging system and increases the efficiency of LGG resections.

To investigate the primary motor cortex (PMC) concerning T2 shortening on T2 echo-planar imaging (EPI-T2) and the double-layer sign on diffusion-weighted imaging (DWI), and also to measure its apparent diffusion coefficient (ADC).3-T MR DWI was performed in 134 adult volunteers and 64 patients. T2 shortening was graded as hypointense or isointense compared with the signal of the superior frontal cortex (SFC). The double-layer sign of the PMC was graded as present or absent. Both findings (T2 shortening and double-layer sign) were evaluated independently by two authors. ADC of the PMC and the SFC were calculated using manually selected ROIs.T2 shortening was found in 131 adults and 62 patients by author 1 and in 132 adults and 61 patients by author 2 (kappa = 0.96 and 0.91). The double-layer sign was found in 131 adults and 61 patients by author 1 and in 127 adults and 58 patients by author 2 (kappa = 0.94 and 0.91). ADC values of the PMC and the SFC were different for all subjects (p0.01).T2 shortening and/or the double-layer sign on 3-T MR can be used to locate the PMC. The difference in ADC values between PMC and SFC is a distinguishing feature.

BACKGROUND AND PURPOSE: 3D-constructive interference in steady state (3D-CISS) sequence has been used to assess the CSF pathways. The aim of this study was to investigate the additive value of 3D-CISS compared with conventional sequences in the diagnosis of obstructive membranes in hydrocephalus. MATERIALS AND METHODS: A total of 134 patients with hydrocephalus underwent MR imaging examination with a 3T unit consisting of turbo spin-echo, 3D-CISS, and cine phase-contrast (cine PC) sequences. 3D-CISS was used to assess obstructive membranes in CSF pathways compared with other sequences. Cine PC, follow-up imaging, and surgical findings were used to confirm obstructive membranes. RESULTS: Comparing the number of noncommunicating cases by using the conventional and 3D-CISS images, we found 26 new cases (19.4%) of 134 cases that were previously misdiagnosed as communicating hydrocephalus by conventional images. 3D-CISS sequence identified obstructive membranes invisible in other sequences, which facilitated selection of neuroendoscopy in the treatment of 31 patients (23.1%) in total who would have been otherwise treated with shunt insertion. These patients included 26 newly diagnosed noncommunicating cases after demonstration of intraventricular and/or fourth ventricular outlet membranes and 5 cases of communicating hydrocephalus with obstructing cisternal membranes. There were obstructions of the foramina of Luschka in 22 of 26 newly found noncommunicating cases. CONCLUSIONS: Conventional sequences are insensitive to obstructive membranes in CSF pathways, especially in the fourth ventricular exit foramina and the basal cisterns. 3D-CISS sequence, revealing these obstructive membranes, can alter patient treatment and prognosis.

We describe a case of extrapontine myelinolysis in a child presenting with chorea and parkinsonian symptoms after treatment for hyponatremic dehydration. Although both extrapontine myelinolysis (EPM) in childhood and extrapyramidal presentation of EPM are very rare in children, the patient presented with pure extrapyramidal symptoms. Besides basal ganglia involvement and sparing brain stem, MRI demonstrated involvement of the amygdala bilaterally hitherto never reported in EPM patients. While single voxel proton spectroscopy (MRS) of the basal ganglia at the beginning was normal, the follow-up MRS showed moderate to severe NAA and mI decrease. Diffusion-weighted imaging abnormalities appeared relatively late during the disease course, also an unexpected finding. In addition, there were apparent increases in apparent diffusion coefficient (ADC) values of the affected basal ganglia instead of diffusion restriction.

Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon malignant CNS tumor typically seen in infant and children less than 3 years of age [1–6]. Although these tumors can be seen at any location in the CNS, approximately half of all tumors are located at the posterior fossa. The striking heterogeneity of the AT/RT apparently reflects the radiologic complexity of these tumors. They are typically large, heterogeneous masses that commonly contain cysts, hemorrhage, calcifications, and solid parts with increased cellularity [1–6]. Approximately 20 % of AT/RT present with disseminated disease at the time of diagnosis.

Both computed tomography (CT) and magnetic resonance imaging (MR) are required for evaluation of clivus chordomas due to anatomic complexity of the skull base, bone involvement, and the proximity of these tumors to many important neural and vascular structures. They have complementary roles in the evaluation of chordoma. The excellent imaging capabilities of MRI and CT allow precise delineation of the clivus chordoma with respect to volume and relation to adjacent structures. The pretreatment goal of the imaging of clivus chordomas is to delineate the tumor margins, adjacent cranial nerves, and vascular structures. The posttreatment goal of the imaging is to define the extent of the surgery; to guide for the additional therapy, if needed; and to differentiate the recurrence from the post-therapy changes. The classical radiologic feature of the clivus chordoma is a destructive soft-tissue mass with calcification due to sequestra from bone destruction and/or dystrophic mineralization (Fig. 1a–c). Intracranial chordomas most often originate from the spheno-occipital synchondrosis of the clivus and located in the midline (Fig. 2). However, it presents with more or less marked symmetric or asymmetric lateral extension (Fig. 3a–j). Furthermore, it may extend into the cavernous sinus, sphenoid sinus, and nasopharynx. But the site of origin is usually along the caudal margin of the clivus, and extension through the foramen magnum is common in younger children (Fig. 4a, b). But it may also be originated from the cranial margin of the clivus (Fig. 5a).

Tuberous sclerosis complex is an autosomal dominant disorder that often causes refractory seizures. The presence of multiple lesions makes it difficult to identify a single lesion responsible for the epilepsy. Our purpose is to assess the single-voxel proton spectroscopic findings of the tubers in 11 children with tuberous sclerosis complex. Prior to age 4 years, all of the patients had presented with epileptic seizures and multiple bilateral tubers in magnetic resonance images. Single-voxel proton spectroscopy was performed from the tubers especially showing epileptogenic activity using both the long and short echo time and in 14 controls. The results were analyzed using the Mann-Whitney U-test. Compared with the control group, the spectroscopic findings of tubers were characterized by decreased N-acetylaspartate to creatine ratios (1.43 ± 0.33 ; P < .001) in both the long and short echo time spectra, increased choline to creatine ratios (0.91 ± 0.082; P < .05), and myo-inositol to creatine ratios (0.97 ± 0.19; P < .01) in the short echo time spectra. A lactate peak was detected in the regions corresponding to an epileptic focus on electroencephalography in six patients. Single-voxel proton spectroscopy could be a useful noninvasive method to evaluate epileptogenic tubers. ( J Child Neurol 2005;20:517-522).

Undecomposed human bodies and organs always attracted interest in terms of understanding biological tissue stability and immortality. Amongst these, cases of natural mummification found in glaciers, bog sediments and deserts caused even more attention. In 2010, an archeological excavation of a Bronze Age layer in a tumulus near the Western Anatolia city Kütahya revealed fire affected regions with burnt human skeletons and charred wooden objects. Inside of the cracked skulls, undecomposed brains were discernible. To analyze the burial taphonomy of the rare phenomenon of brain preservation, we analyzed brains, bone, teeth and surrounding soils elements using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Adipocere formation or saponification of postmortem tissue fat requires high levels of alkalinity and especially potassium. Indeed, ICP-MS analysis of the brain, teeth and bone and also of the surrounding soil revealed high levels of potassium, magnesium, aluminum and boron, which are compatible with the famous role of Kütahya in tile production with its soil containing high level of alkalines and tile-glazing boron. Fatty acid chromatography revealed simultaneous saturation of fats and protection of fragile unsaturated fatty acids consistent with soil-presence of both pro-oxidant and anti-oxidant trace metals. Computerized tomography revealed protection of diencephalic, metencephalic and occipital tissue in one of the best-preserved specimens. Boron was previously found as an intentional preservative of Tutankhamen and Deir el Bahari mummies. Here, in natural soil with its insect-repellant, anti-bacterial and fire-resistance qualities it may be a factor to preserve heat-affected brains as almost bioporcellain specimens. © 2013 Elsevier GmbH.

Subependymal giant cell astrocytomas are benign tumors that constitute one of the primary features of tuberous sclerosis. Two infants with tuberous sclerosis had very unusual subependymal giant cell astrocytomas, confirmed on biopsy in one of the infants. In both cases, contrast-enhanced cranial magnetic resonance imaging suggested a calcified intra-axial mass with diffuse basal ganglia involvement extending into the lateral ventricle. Computed tomography confirmed calcification in both cases. The first patient had right temporal lobectomy for intractable epilepsy. Biopsy of the basal ganglia lesion in that case suggested subependymal giant cell astrocytoma. In infants, subependymal giant cell astrocytomas can present with unusual morphology and may feature diffuse basal ganglia involvement and severe calcification.

Rasmussen's syndrome is characterized by intractable seizures and progressive neuropsychiatric deterioration secondary to unilateral cortical inflammation and tissue destruction. Diagnosis of Rasmussen's syndrome in the early phase depends mainly on the clinical features. Neuroimaging and histopathologic examinations may not be specific during this period. We report a case of Rasmussen's syndrome followed by serial MRI and magnetic resonance spectroscopy (MRS) studies over a 3- to 16-month period. A healthy 6-year-old boy presented with focal motor seizures. An MRI study demonstrated prominent enlargement and T2 hyperintensity of the left mesial temporal lobe and perisylvian region. This early finding evolved to volume loss and later progressive atrophy of the ipsilateral hemisphere when epilepsia partialis continua occurred. Being aware of those early MRI features in a patent with increasing frequency of focal motor seizures should suggest Rasmussen's syndrome. In addition, we found prominently increased myoinositol concentration in atrophic cortex which might reflect increased gliosis in the late period of the disease.

3-Hydroxy-3-Methylglutaryl coenzyme A lyase (HMG-CoA) deficiency is a rare inborn error of leucine catabolism. The disease is characterized by recurrent episodes of metabolic acidosis, hyperammonemia without ketosis, hypoglycemia, lethargy, hepatomegaly, and seizures. This study has evaluated the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) findings of three patients with HMG-CoA deficiency. The common findings on all of the MRI scans were multiple, coalescent, marked lesions in periventricular white matter and arcuate fibers, most prominently in frontal or periatrial regions that were superimposed on diffuse, slightly hyperintense subcortical white matter signal. Involvement of the caudate nucleus and the dentate nucleus were observed in the reported patients. MRS studies by both STEAM and PRESS spectra of all patients revealed a decrease in N-acetylaspartate and elevation in both myoinositol and choline. A pathologic peak at 1.33 ppm, which is compatible with lactate, and a particular peak at 2.42 ppm in all patients were also found. The combination of both MRI and MRS findings could be considered as being specific in patients with HMG-CoA lyase deficiency.

Purpose: To evaluate the consistency of fat in the high intensity signals of the normal neurohypophysis and to differentiate the high signal of posterior pituitary from that of dorsum sella. Sagittal SE T1-weighted images with frequency encoding in the horizontal direction were used in order to differentiate the high signal of posterior pituitary and dorsum sella by the vertically-oriented chemical shift artifact. Material and Methods: The sellae of 46 normal volunteers were imaged with a commercially available fat suppression technique and SE sequences with frequency encoding in vertical (25 cases) and horizontal (21 cases) axes. Results: The high signal intensity was absent in 9% of the normal volunteers with no predilection to any specific age group. None of the cases with posterior pituitary high intensity signals showed suppression of the signal with fat suppression technique. A fat suppression technique was helpful in documenting the hyperintensity in 7% of normal volunteers. Nineteen of the 21 (90%) cases with high signal intensity were detected by routine SE T1-weighted images, whereas 18 of the 19 (95%) cases were detected by imaging with frequency encoding in the horizontal direction. Conclusion: The high signal does not indicate the presence of fat. Fat suppression technique and a horizontal direction of frequency encoding help in differentiating the high signal of the neurohypophysis from that of dorsum sella.

The goal of surgery in high-grade gliomas is to maximize the resection of contrast-enhancing tumor without causing additional neurological deficits. Intraoperative MRI improves surgical results. However, when using contrast material intraoperatively, it may be difficult to differentiate between surgically induced enhancement and residual tumor. The purpose of this study was to assess the usefulness of intraoperative dynamic contrast-enhanced T1-weighted MRI to guide this differential diagnosis and test it against tissue histopathology.Preoperative and intraoperative dynamic contrast-enhanced MRI was performed in 21 patients with histopathologically confirmed WHO Grade IV gliomas using intraoperative 3-T MRI. Standardized regions of interest (ROIs) were placed manually at 2 separate contrast-enhancing areas at the resection border for each patient. Time-intensity curves (TICs) were generated for each ROI. All ROIs were biopsied and the TIC types were compared with histopathological results. Pharmacokinetic modeling was performed in the last 10 patients to confirm nonparametric TIC analysis findings.Of the 42 manually selected ROIs in 21 patients, 25 (59.5%) contained solid tumor tissue and 17 (40.5%) retained the brain parenchymal architecture but contained infiltrating tumor cells. Time-intensity curves generated from residual contrast-enhancing tumor and their preoperative counterparts were comparable and showed a quick and persistently increasing slope ("climbing type"). All 17 TICs obtained from regions that did not contain solid tumor tissue were undulating and low in amplitude, compared with those obtained from residual tumors ("low-amplitude type"). Pharmacokinetic findings using the transfer constant, extravascular extracellular volume fraction, rate constant, and initial area under the curve parameters were significantly different for the tumor mass, nontumoral regions, and surgically induced contrast-enhancing areas.Intraoperative dynamic contrast-enhanced MRI provides quick, reproducible, high-quality, and simply interpreted dynamic MR images in the intraoperative setting and can aid in differentiating surgically induced enhancement from residual tumor.

Object The authors had previously shown that 3-T intraoperative MRI (ioMRI) detects residual tumor tissue during low-grade glioma and that it helps to increase the extent of resection. In a proportion of their cases, however, the ioMRI disclosed T2-hyperintense areas at the tumor resection border after the initial resection attempt and prompted a differential diagnosis between residual tumor and nontumoral changes. To guide this differential diagnosis the authors used intraoperative long-TE single-voxel proton MR spectroscopy (ioMRS) and tested the correlation of these findings with findings from pathological examination of resected tissue. Methods Patients who were undergoing surgery for hemispheric or insular WHO Grade II gliomas and were found to have T2 changes around the resection cavity at the initial ioMRI were prospectively examined with ioMRS and biopsies were taken from corresponding localizations. In 14 consecutive patients, the ioMRS diagnosis in 20 voxels of interest was tested against the histopathological diagnosis. Intraoperative diffusion-weighted imaging (ioDWI) was also performed, as a part of the routine imaging, to rule out surgically induced changes, which could also appear as T2 hyperintensity. Results Presence of tumor was documented in 14 (70%) of the 20 T2-hyperintense areas by histopathological examination. The sensitivity of ioMRS for identifying residual tumor was 85.7%, the specificity was 100%, the positive predictive value was 100%, and the negative predictive value was 75%. The specificity of ioDWI for surgically induced changes was high (100%), but the sensitivity was only 60%. Conclusions This is the first clinical series to indicate that ioMRS can be used to differentiate residual tumor from nontumoral changes around the resection cavity, with high sensitivity and specificity.