How tissue T1-variability influences DCE-MRI perfusion parameters estimation of recurrent high-grade glioma after surgery followed by radiochemotherapy.

BACKGROUND: Quantification of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) kinetic parameters (KPs) requires a determination of native tissue T1. Two approaches are adopted: (i) tissue T1-maps are acquired; and (ii) an a priori T1 value (fT1) is fixed for all patients (fT1-approach). Although it is more attractive, the fT1-approach might bias the results of KP calculations due to tissue T1 variability. PURPOSE: To quantify the tissue T1 variability of recurrent high-grade glioma (HGG) and the error in KP estimation when the fT1-approach is adopted. MATERIAL AND METHODS: We reviewed the postoperative MRI scans of 28 patients with recurrent HGG after radiochemotherapy. MRI study included T1-maps from multiple-dynamic multiple-echo imaging, DCE-MRI, and contrast enhanced T1-weighted images. KPs were calculated using T1-map and fT1-approach. RESULTS: The tissue T1 variability of recurrent HGG was relevant. The absolute error in KP estimation, as a function of the deviation of fT1 from the true value, was 8% every 100 ms. The difference between the KPs obtained with fT1-approach from fT1 values of 1300, 1390, and 1500 ms and their reference values were mostly within the 95% confidence interval (± 1.96 standard deviation). Conversely, using fT1 values of 900, 1200, 1600, and 1900 ms causes a significant error in KP estimation (P<0.05). CONCLUSION: Recurrent HGG is characterized by a substantial T1 variability. Although the fT1-approach does not account for this variability, it results in a minor effect on the KP estimations provided the fT1 value is in the range of 1300-1500 ms.

Some evidence on Gerstmann's syndrome: A case study on a variant of the clinical disorder.

We describe the case of a bilingual patient with persistent symptoms largely, although not fully, consistent with those that are usually reported in Gerstmann's syndrome. Twenty months after a spontaneous primary intracranial hemorrhage, the patient was evaluated with a series of neuropsychological tasks and underwent an MRI investigation based on Diffusion Tensor Imaging probabilistic tractography. The patient suffered from dysgraphia (difficulty in the access to the graphemic representation of letter forms), autotopoagnosia (difficulties in locating body parts on verbal command), right-left confusion (difficulties in localizing right and left side of symmetrical body parts), and number processing/calculation impairments (predominant difficulties on transcoding tasks). Probabilistic tractography revealed a relatively spared superior longitudinal fasciculus and severe damage to the subcortical white matter connecting the angular gyrus with other parietal regions, such as the intraparietal sulcus and the supramarginal gyrus. Within the framework of the contemporary cognitive accounts of Gerstmann's syndrome, the case supports the assumption of an anatomical intraparietal disconnection more than a functional Grundstörung (core impairment).

Predicting MGMT Promoter Methylation of Glioblastoma from Dynamic Susceptibility Contrast Perfusion: A Radiomic Approach.

BACKGROUND AND PURPOSE: This study aims to investigate whether radiomic quantitative image features (IFs) from perfusion dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) retain sufficient strength to predict O6-methylguanine-DNA methyltransferase promoter methylation (MGMT_pm) in newly diagnosed glioblastoma (GB) patients. METHODS: We retrospectively reviewed the perfusion DSC-MRI of 59 patients with GB. Patients were classified into three groups: (1) unmethylated if MGMT_pm ≤ 9% (UM); (2) intermediate-methylated if MGMT_pm ranged between 10% and 29% (IM); (3) methylated if MGMT_pm ≥ 30% (M). A total of 92 quantitative IFs were obtained from relative cerebral blood volume and relative cerebral blood flow maps. The Mann-Whitney U-test was applied to assess whether there were statistical differences in IFs between patient groups. Those IFs showing significant difference between two patient groups were termed relevant IFs (rIFs). rIFs were uploaded to a machine learning model to predict the MGMT_pm. RESULTS: No rIFs were found between UM and IM groups. Fourteen rIFs were found among UM-M, IM-M, and (UM + IM)-M groups. We built a multilayer perceptron deep learning model that classified patients as belonging to UM + IM and M group. The model performed well with 75% sensitivity, 85% specificity, and an area under the receiver-operating curve of .84. CONCLUSION: rIFs from perfusion DSC-MRI are potential biomarkers in GBs with a ≥30% MGMT_pm. Otherwise, unmethylated and intermediate-methylated GBs lack of rIFs. Five of 14 rIFs show sufficient strength to build an accurate prediction model of MGMT_pm.

Robust association between vascular habitats and patient prognosis in glioblastoma: An international multicenter study.

BACKGROUND: Glioblastoma (GBM) is the most aggressive primary brain tumor, characterized by a heterogeneous and abnormal vascularity. Subtypes of vascular habitats within the tumor and edema can be distinguished: high angiogenic tumor (HAT), low angiogenic tumor (LAT), infiltrated peripheral edema (IPE), and vasogenic peripheral edema (VPE). PURPOSE: To validate the association between hemodynamic markers from vascular habitats and overall survival (OS) in glioblastoma patients, considering the intercenter variability of acquisition protocols. STUDY TYPE: Multicenter retrospective study. POPULATION: In all, 184 glioblastoma patients from seven European centers participating in the NCT03439332 clinical study. FIELD STRENGTH/SEQUENCE: 1.5T (for 54 patients) or 3.0T (for 130 patients). Pregadolinium and postgadolinium-based contrast agent-enhanced T1 -weighted MRI, T2 - and FLAIR T2 -weighted, and dynamic susceptibility contrast (DSC) T2 * perfusion. ASSESSMENT: We analyzed preoperative MRIs to establish the association between the maximum relative cerebral blood volume (rCBVmax ) at each habitat with OS. Moreover, the stratification capabilities of the markers to divide patients into "vascular" groups were tested. The variability in the markers between individual centers was also assessed. STATISTICAL TESTS: Uniparametric Cox regression; Kaplan-Meier test; Mann-Whitney test. RESULTS: The rCBVmax derived from the HAT, LAT, and IPE habitats were significantly associated with patient OS (P < 0.05; hazard ratio [HR]: 1.05, 1.11, 1.28, respectively). Moreover, these markers can stratify patients into "moderate-" and "high-vascular" groups (P < 0.05). The Mann-Whitney test did not find significant differences among most of the centers in markers (HAT: P = 0.02-0.685; LAT: P = 0.010-0.769; IPE: P = 0.093-0.939; VPE: P = 0.016-1.000). DATA CONCLUSION: The rCBVmax calculated in HAT, LAT, and IPE habitats have been validated as clinically relevant prognostic biomarkers for glioblastoma patients in the pretreatment stage. This study demonstrates the robustness of the hemodynamic tissue signature (HTS) habitats to assess the GBM vascular heterogeneity and their association with patient prognosis independently of intercenter variability. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1478-1486.

The Influence of Contrast-to-Noise Ratio on the Discrimination Between Cortical and Juxtacortical Lesions in Multiple Sclerosis.

OBJECTIVE: The objective of this study was to investigate the contrast-to-noise ratio (CNR) between cortical gray matter (GM) and subcortical white matter (WM) across the cortex in relation to the ability of 3-dimensional fluid attenuated inversion recovery and 3-dimensional double inversion recovery to distinguish between cortical lesions (CLs) and juxtacortical lesions (JCs). METHODS: A total of 38 multiple sclerosis patients underwent magnetic resonance imaging. Two neuroradiologists scored CLs and JCs on magnetic resonance imaging in 9 cerebral areas. Lesions were marked as nonclassifiable (NCs) when blurred WM-GM boundary leads to inaccuracy of their discrimination. The CNR between WM and GM (CNRWM-GM) was evaluated across the cortical areas. RESULTS: The CNRWM-GM varies across the cortex; the lower values were found in motor and sensorimotor areas where almost all NCs were localized. A strong negative correlation was found between CNRWM-GM and NCs. CONCLUSIONS: Discrimination between CLs and JCs is affected from the sharp visualization of the WM-GM boundary, which is directly related to CNRWM-GM.

Spinal cord lesions are frequently asymptomatic in relapsing-remitting multiple sclerosis: a retrospective MRI survey.

BACKGROUND: Spinal cord (SC) involvement correlates with poor prognosis in patients with multiple sclerosis (MS). Nevertheless, there is no consensus on the use of SC-MRI at follow-up, mainly because of the belief that SC lesions are nearly always symptomatic. OBJECTIVES: The aim of the present study was to investigate the frequency of asymptomatic SC combined unique activity (CUA, new/enlarging T2 or gadolinium-positive [Gd+] lesions) on MRI in a cohort of patients diagnosed with clinically isolated syndrome (CIS) or relapsing-remitting MS (RRMS). METHODS: We retrospectively investigated all scans showing SC-CUA in patients with CIS or RRMS referred to a single Italian MS centre. We determined whether they were symptomatic and whether they had associated brain radiological activity. RESULTS: In 340 SC-MRI scans with SC-CUA (230 patients), SC-CUA was asymptomatic in 31.2%; 12.1% of SC-CUA had neither clinical activity nor brain radiological activity (44.5% and 25.4%, respectively, considering only follow-up SC-CUA). At multivariate analysis asymptomatic SC-CUAs were associated with older age at onset (34.0 ± 10.37 vs 31.0 ± 9.99 years, p = 0.006), non-spinal onset (76.4 vs 47.4%, p < 0.001), lower EDSS score at MRI (1.8 ± 0.93 vs 2.4 ± 1.28, p = 0.001) and lower number of Gd+ SC lesions (0.1 ± 0.33 vs 0.3 ± 0.54, p = 0.04), compared to symptomatic SC-CUAs. CONCLUSIONS: A substantial proportion of our patients had SC-CUA without clinical symptoms and/or without concomitant brain MRI activity. In these patients, SC-CUA was the only sign of disease activity, suggesting that regular SC-MRI follow-up is required for reliable assessment of radiological activity and may improve the management of patients with MS.

Explicit Motor Imagery for Grasping Actions in Children With Spastic Unilateral Cerebral Palsy.

Background: Motor Imagery (MI) refers to mental simulation of a motor action without producing any overt movement. Previous studies showed that children with Unilateral Cerebral Palsy (UCP) are impaired in implicit MI, as demonstrated by the performance of Hand Laterality Judgment tasks. The aim of this study was to examine the specificity of explicit MI deficits in UCP children. Methods: A group of UCP children (n = 10; aged 9-14) performed a mental chronometry task consisting in grasping an object and placing it into a container, or in imagining to perform the same action. As control, a group of typically developing (TD) children, matched by age, performed the same task. Movement durations for executed and imagined trials were recorded. A subgroup of 7 UCP children and 10 TD children also underwent a session of functional MRI to examine the activation of parieto-frontal areas typically associated to MI processes, during the imagination of reaching-grasping actions performed with the paretic hand. Results: Behavioral results revealed the existence of a correlation between executed and imagined movement durations both in TD and UCP groups. Moreover, the regression analysis in TD children showed that higher scores in mental chronometry tasks were positively correlated to increased bilateral activation of the intraparietal sulcus (IPS), superior parietal lobule (SPL), and dorsal premotor (PMd) cortex. A similar analysis revealed in the UCP group a positive correlation between a higher score in the mental chronometry task and bilateral activations of IPS, and to activation of contralesional, right PMd, and putamen during imagination of grasping movements. Conclusions: These results provide new insights on the relationship between MI capacity and motor deficits in UCP children, suggesting the possibility of the use of explicit MI training to improve patient's upper limb motor functions.

Application of an Intensive Rehabilitation Program After Very Late Recovery of Consciousness: A Single-Case Neurorehabilitation and Neuroimaging Study.

Late recovery of consciousness in vegetative state is considered as an exceptional outcome and has been reported prevalently in patients who suffered a traumatic brain injury. In these patients, the benefits of prolonging the rehabilitation, aimed at the recovery of autonomy in basic everyday activities, has been demonstrated. Here, we describe the application of an intensive multi-professional rehabilitation program carried out on a young female patient, with exceptionally late recovery of consciousness, specifically, after 7 years of vegetative state due to severe brain hemorrhage. Neuropsychological and functional assessment was conducted before and after the end of the rehabilitation program. In addition, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI)-based probabilistic tractography were performed. Two follow-up neuropsychological and functional assessments were also conducted 6 and 29 months after the conclusion of the program. Functional results showed an improvement, maintained over time, in walking with assistance, cognitive efficiency, visual acuity and visual field, dysarthria, and execution of activities of daily living. Moreover, functional and structural magnetic resonance imaging (MRI) data documented the existence of preserved neural networks involved in sensory, motor, and linguistic tasks, which in all likelihood support the recovery process. This report suggests the possibility of undertaking an intensive rehabilitation program in patients who remain for long periods in altered states of consciousness, in spite of early negative prognosis.

ASSESSMENT OF MOVEMENT-INDUCED TIME-VARYING MAGNETIC FIELDS EXPOSURE IN MAGNETIC RESONANCE IMAGING BY A COMMERCIAL PORTABLE MAGNETOMETER.

The purpose of this study was to describe a simple procedure to assess head exposure of MRI workers to time-varying magnetic field, due to their movements in the static magnetic field of a 3T MRI scanner. A group of MRI workers were provided with a commercial portable meter that stored in its internal memory the instantaneous B values. The dB/dt was obtained by the post hoc processing of measured data. The movement-induced time-varying electric field (TVEF) was calculated from dB/dt. The weighted peak index was evaluated in the frequency domain, by first computing the spectrum of dB/dt waveform, to verify the compliance with the exposure limits. The portable magnetometer may be useful to locally explore the MRI workers exposure to time-varying magnetic field and perform the local risk assessments in order to carry out the obligations laid down by Directive 2013/35/EU.

Rehabilitation of unilateral spatial neglect: A combined behavioral and fMRI single-case study.

OBJECTIVE: Symptoms of visuospatial neglect occur frequently after unilateral brain damage. Neglect hampers general rehabilitation progress and is associated with reduced quality of life. Some of the rehabilitation programs developed to treat neglect have demonstrated behavioral improvements. However, only a few of them have addressed specifically the anatomo-functional correlates associated behavioral improvement. METHOD: Here we describe the case of a patient (GV) with a severe left neglect disorder as a consequence of a right hemisphere stroke. Eighteen weeks after the onset, he underwent a 10-week intensive neuropsychological rehabilitation program. Functional MRI (fMRI) during execution of a covert attention task, and a broad neuropsychological assessment were conducted before and after the training. RESULTS: The results show a significant improvement of the performance in neglect tasks after the rehabilitation program, although the remission of symptoms was not complete. fMRI data showed that the behavioral improvement was accompanied by an increase of activity in the dorsal premotor cortex and middle frontal gyrus bilaterally. Other activations were present only in the contralesional left hemisphere, including supplementary motor area and superior temporal gyrus. CONCLUSIONS: The implications of the results are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Arterial Spin Labeling MRI to Measure Cerebral Blood Flow in Untreated Ischemic Stroke.

BACKGROUND AND PURPOSE: This study aims to investigate the significance of regional hyperperfusion (RH) detected by arterial spin labeling (ASL) in a group of untreated stroke patients, within 24-36 hours after symptom onset. The relationship between RH volume and infarcted volume (DIV) as defined on diffusion weighted images (DWIs) was evaluated. METHODS: Of the 346 consecutive acute stroke patients who attended our center, we retrospectively reviewed MRI studies of 47 patients who were ineligible for standard treatment with intravenous tissue plasminogen activator. The MRI study included ASL and DWI. The ASL-derived cerebral blood flow (CBF) maps were coregistered on the DWI images. RH volume and DIV were calculated and compared. Patient NIHSS scores were also evaluated at admission, discharge, and after 1 and 6-month follow-up. RESULTS: Twenty-two patients showed RH with CBF twice than baseline. In all 22 patients, RH overlaps with DWI infarcted area. No significant difference (P = .94) between RH volume and DIV was found (7.2 ± 9.6 and 9.0 ± 11.9 cm3 ). The Pearson's correlation coefficient between RH and DIV was .93. On univariate analysis, a significant difference was found between patient's groups on NIHSS at any time points, after covariates adjustment NIHSS difference was significant only at admission. CONCLUSIONS: The study showed that ASL perfusion could be an integral part of the MRI examination in the assessment of 24-36 hours not-treated stroke patients as sustained RH group had improved outcomes. More importantly, ASL perfusion may provide evidence of beneficial effects of reperfusion induced by recanalization treatment.

Meeting with triumph and disaster: Osimertinib in T790M-unknown CNS progression in EGFR-mutated non-small cell lung cancer.

INTRODUCTION: Treatment paradigms for EGFR-mutated non-small cell lung cancer (NSCLC) have successfully evolved since the introduction of osimertinib. The detection of EGFR T790M mutation in plasma or tumor samples obtained at disease progression to first-/second-generation EGFR inhibitors is mandatory for osimertinib prescription. Nevertheless, pharmacokinetics properties of osimertinib guarantee its usefulness in central nervous system (CNS) disease even in the case of T790M-negative or unknown status. PATIENTS AND METHODS: In this brief report, we share the clinical histories of two patients with CNS-preeminent progression under first-/second-generation EGFR inhibitors in which it was not possible to document the presence of T790M resistance mutation. RESULTS: Patient outcomes diverged dramatically due to the differential availability of off-label osimertinib. CONCLUSIONS: Waiting for the novel molecule to be approved and licensed in first-line treatment, our report of hope and frustration is intended to stress the opportunity of its administration in the case of CNS failure of first-line EGFR inhibition, even in the absence of T790M proof.

Correlation between cortical lesions and cognitive impairment in multiple sclerosis.

OBJECTIVES: Gray matter (GM) damage is well known as a fundamental aspect of multiple sclerosis (MS). Above all, cortical lesions (CLs) burden, detectable at MRI with double inversion recovery (DIR) sequences, has been demonstrated to correlate with cognitive impairment (CI). The aim of this study was to investigate the role of CLs number in predicting CI in a cohort of patients with MS in a clinical practice setting. MATERIALS AND METHODS: Thirty consecutive patients with MS presenting CLs (CL+) at high-field (3.0 T) MRI 3D-DIR sequences and an even group of MS patients without CLs (CL-) as a control, were investigated with the Rao Brief Repeatable Battery of Neuropsychological Tests (BRB), Version A. Total and lobar CLs number were computed in CL+ patients. RESULTS: Among the sixty patients with MS enrolled, forty-seven (78.3%) had a relapsing-remitting course, while thirteen (21.7%) a progressive one, eleven secondary progressive, and two primary progressive. Compared to CL-, CL+ patients had a greater proportion of progressive forms (p = .03). The most affected region was the frontal lobe (73.3% of patients), followed by temporal and parietal ones (both 60.0%). Multivariate (logistic regression) analysis revealed a significant correlation between total CLs number and the presence of mild cognitive impairment defined as pathologic score in at least one BRB test (p = .04); it was also correlated with deficit at PASAT 3 (p = .05) and Stroop Test (p = .02). CONCLUSIONS: We confirmed CLs number, evaluated with a technique quite commonly available in clinical practice, as a predictive factor of CI in patients with MS, in order to improve the diagnosis and management of CI and monitor potential neuroprotective effects of therapies.

The Prognostic Roles of Gender and O6-Methylguanine-DNA Methyltransferase Methylation Status in Glioblastoma Patients: The Female Power.

BACKGROUND: Clinical and molecular factors are essential to define the prognosis in patients with glioblastoma (GBM). O6-methylguanine-DNA methyltransferase (MGMT) methylation status, age, Karnofsky Performance Status (KPS), and extent of surgical resection are the most relevant prognostic factors. Our investigation of the role of gender in predicting prognosis shows a slight survival advantage for female patients. METHODS: We performed a prospective evaluation of the Project of Emilia Romagna on Neuro-Oncology (PERNO) registry to identify prognostic factors in patients with GBM who received standard treatment. RESULTS: A total of 169 patients (99 males [58.6%] and 70 females [41.4%]) were evaluated prospectively. MGMT methylation was evaluable in 140 patients. Among the male patients, 36 were MGMT methylated (25.7%) and 47 were unmethylated (33.6%); among the female patients, 32 were methylated (22.9%) and 25 were unmethylated (17.9%). Survival was longer in the methylated females compared with the methylated males (P = 0.028) but was not significantly different between the unmethylated females and the unmethylated males (P = 0.395). In multivariate analysis, gender and MGMT methylation status considered together (methylated females vs. methylated males; hazard ratio [HR], 0.459; 95% confidence interval [CI], 0.242-0.827; P = 0.017), age (HR, 1.025; 95% CI, 1.002-1.049; P = 0.032), and KPS (HR, 0.965; 95% CI, 0.948-0.982; P < 0.001) were significantly correlated with survival. CONCLUSIONS: Survival was consistently longer among MGMT methylated females compared with males. Gender can be considered as a further prognostic factor.

Correction to: Which elderly newly diagnosed glioblastoma patients can benefit from radiotherapy and temozolomide? A PERNO prospective study.

The members of the PERNO Study Group were not individually captured in the metadata of the original publication. They are included in the metadata of this publication.

Bilateral surgical damage of the central tegmental tract resulting in bilateral hypertrophic olivary degeneration: An MRI case report.

Hypertrophic olivary degeneration (HOD) is a rare trans-synaptic neuronal degeneration of the inferior olivary nucleus caused by an injury to the dentato-rubro-olivary connection, also known as Guillain-Mollaret triangle. It leads to hypertrophy of the affected nucleus rather than atrophy and is characterized by hyperintensity on T2-weighted images. Unilateral and bilateral cases are described. We present a case of a 70-year-old patient affected by a tumor inside the fourth ventricle who suffered from diplopia and right seventh cranial nerve palsy. He underwent surgery and developed left seventh cranial nerve palsy. Three months after resection, magnetic resonance imaging revealed the appearance of bilateral HOD. This is the first report of bilateral HOD occurrence after surgical bilateral damage of the rubro-olivary fibers running in central tegmental tracts.

2-Hydroxyglutarate Detection by Short Echo Time Magnetic Resonance Spectroscopy in Routine Imaging Study of Brain Glioma at 3.0 T.

OBJECTIVE: The objective of this study was to assess the effective performance of short echo time magnetic resonance spectroscopy (short TE MRS) for 2HG detection as biomarker of isocitrate dehydrogenase (IDH) status in all grade glioma (GL). METHODS: A total of 82 GL patients were prospectively investigated by short TE MRS at 3.0 T as part of a multimodal magnetic resonance imaging study protocol. Spectral analysis was performed using linear combination model. Tumor specimens were diagnosed as IDH mutant or wild type according to the 2016 World Health Organization (WHO) classification of brain tumors. Spectra were analyzed for the presence of 2HG. The performance of short TE MRS was evaluated in terms of sensitivity, specificity, and positive and negative likelihood ratio on the overall sample and on GL WHO grades II and III and glioblastoma separately. RESULTS: The specificity and sensitivity estimated on the overall sample were 88% and 77%, respectively. In GL WHO grades II and III, 100% specificity and 75% sensitivity were estimated. CONCLUSIONS: We reiterate the feasibility to identify IDH status of brain GL using short TE MRS at 3.0 T. The method can correctly detect 2HG as expression of IDH mutation in WHO grades II and III GL with a 100% specificity but a 75% sensitivity. In the evaluation of glioblastoma, short TE MRS performs poorly having a 17% false positive rate.

T2*-Correction in Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Glioblastoma From a Half Dose of High-Relaxivity Contrast Agent.

OBJECTIVE: The aim of this study was to evaluate the arterial input function (AIF) and tissue enhancement time curve (tissue function [TF]) obtained after the administration of a half-dose gadobenate dimeglumine (0.05-mmol/kg body weight [bw]) compared with a full dose (0.1-mmol/kg bw) of a standard-relaxivity contrast agent. METHODS: We enrolled 40 adult patients with glioblastoma in an interindividual comparative study. Patients were randomized to 1 of the 2 study arms: 20 patients received 0.1-mmol/kg bw of gadoterate; the other 20 patients received 0.05-mmol/kg bw of gadobenate. The patients underwent dynamic contrast-enhanced magnetic resonance imaging examinations. Arterial input function, tissue enhancement time curve (TF), tumor transfer rate (K), and tumor extracellular-extravascular volume fraction (Ve) were calculated for each patients. Averaged AIF, TF, K, and Ve of both groups were compared. RESULTS: A significant difference (P = 0.001) between the peak AIF values obtained with the 2 different gadolinium-based contrast agents was observed. No difference was found between TFs (P = 0.35). Comparison on kinetic parameters revealed a significant difference for K (P = 0.047) but no difference for Ve (P = 0.74). CONCLUSIONS: The administration of half dose of the high-relaxivity contrast agent gadobenate is effective in improving AIF by reducing T2*-shortening effects on dynamic contrast-enhanced magnetic resonance imaging and ensuring at the same time an adequate signal enhancement in tumor tissue. The use of 0.05-mmol/kg bw of gadobenate not only is feasible but also can lead to a better estimation of K based on a more accurate AIF assessment.

Effectiveness of a high relaxivity contrast agent administered at half dose in dynamic susceptibility contrast MRI of brain gliomas.

PURPOSE: To determine whether half of the approved dose of gadobenate dimeglumine (MultiHance) is as effective as a full dose of gadoterate meglumine (Dotarem) for qualitative and quantitative cerebral blood volume (CBV) perfusion evaluation at 3T in patients with brain gliomas. MATERIALS AND METHODS: We enrolled 65 adult patients in an interindividual comparative study. Patients were randomized to one of two study arms: 33 patients received 0.1 mmol/kg body weight (bw) of gadoterate, 32 patients received 0.05 mmol/kg bw of gadobenate. The patients underwent identical examinations at 3T. Arterial input function (AIF), tissue function (TF), and the maximum tumor CBV (CBV_T) were obtained from each patient. The quality of the CBV maps were independently reviewed by two neuroradiologists blinded to the administered contrast agent. RESULTS: The administration of a half dose of gadobenate led to a roughly 40% reduction in signal drop compared to that achieved with a full dose of gadoterate (P values for AIF and TF maximum and integral were <0.01); quantitative and qualitative assessment of CBV maps revealed no difference between contrast agents (P values for CBV_T of high- and low-grade gliomas, image quality evaluation were 0.87, 0.48, >0.65, respectively) CONCLUSION: The CBV maps obtained with a half dose gadobenate (0.05 mmol/kg bw) are of comparable diagnostic quality as the corresponding images acquired with a full dose of gadoterate (0.1 mmol/kg bw). LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:500-506.