T1-weighted Gadolinium Enhancement Research Articles

ACT-1 A PROSPECTIVE MULTICENTER PHASE I/IIA STUDY OF PREOPERATIVE NEOADJUVANT BEVACIZUMAB FOR NEWLY DIAGNOSED GLIOBLASTOMA

Abstract Background Preoperative neoadjuvant bevacizumab (neoBev) reduces enhancement and perifocal edema by inhibition of angiogenesis and vascular permeability for glioblastoma (GBM). The aim of this study was to investigate safety and efficacy of neoBev for newly diagnosed GBM through an exploratory prospective multi-center study. METHODS & PATIENTS 15 patients with newly diagnosed GBM were enrolled in the present study. Eligibility was a patient with a brain tumor representing with ring-shaped enhancement and perifocal edema on magnetic resonance imaging (MRI). Based on neuroimage of typical GBM, neoBev and temozolomide (TMZ) were administered prior to craniotomy. Two weeks after neoBev, the tumor volume on T1-weighted gadolinium enhancement (T1Gd) and fluid attenuated inversion recovery (FLAIR) were assessed. Three to four weeks after neoBev and TMZ administration, patients underwent surgical resection. The primary endpoint was feasibility and safety, and the secondary endpoint was efficacy. Adverse events including systemic toxicity and wound healing delay during radiation (RT), TMZ, and Bev combined therapy were carefully monitored throughout clinical course including extent of resection. RESULTS Average of tumor regression rate two weeks after neoBev on T1Gd and FLAIR were 37.0% and 54.0%, respectively. Cerebral blood flow and cerebral blood volume were reduced after neoBev. Patients underwent surgical resection safely without excess blood loss due to less vascular and less degree of brain swelling. Two patients underwent awake surgery without any complications. Postoperative MRI showed that the all tumors were totally removed except one with multiple invasive tumors. Histological diagnosis of all patients was GBM, IDH-1 wild-type. Postoperative course was uneventful without neurological deficit and adverse effects except one postoperative hematoma in the resection cavity and one wound infection due to wound dehiscence. CONCLUSION Preoperative neoBev for newly diagnosed GBM might contribute to safe surgery. Clinical outcome of this therapeutics is now currently under investigation.

A Deep Learning Model for Preoperative Differentiation of Glioblastoma, Brain Metastasis and Primary Central Nervous System Lymphoma: A Pilot Study.

BackgroundNeuroimaging differentiation of glioblastoma, primary central nervous system lymphoma (PCNSL) and solitary brain metastasis (BM) remains challenging in specific cases showing similar appearances or atypical features. Overall, advanced MRI protocols have high diagnostic reliability, but their limited worldwide availability, coupled with the overlapping of specific neuroimaging features among tumor subgroups, represent significant drawbacks and entail disparities in the planning and management of these oncological patients.ObjectiveTo evaluate the classification performance metrics of a deep learning algorithm trained on T1-weighted gadolinium-enhanced (T1Gd) MRI scans of glioblastomas, atypical PCNSLs and BMs.Materials and MethodsWe enrolled 121 patients (glioblastoma: n=47; PCNSL: n=37; BM: n=37) who had undergone preoperative T1Gd-MRI and histopathological confirmation. Each lesion was segmented, and all ROIs were exported in a DICOM dataset. The patient cohort was then split in a training and hold-out test sets following a 70/30 ratio. A Resnet101 model, a deep neural network (DNN), was trained on the training set and validated on the hold-out test set to differentiate glioblastomas, PCNSLs and BMs on T1Gd-MRI scans.ResultsThe DNN achieved optimal classification performance in distinguishing PCNSLs (AUC: 0.98; 95%CI: 0.95 - 1.00) and glioblastomas (AUC: 0.90; 95%CI: 0.81 - 0.97) and moderate ability in differentiating BMs (AUC: 0.81; 95%CI: 0.70 - 0.95). This performance may allow clinicians to correctly identify patients eligible for lesion biopsy or surgical resection.ConclusionWe trained and internally validated a deep learning model able to reliably differentiate ambiguous cases of PCNSLs, glioblastoma and BMs by means of T1Gd-MRI. The proposed predictive model may provide a low-cost, easily-accessible and high-speed decision-making support for eligibility to diagnostic brain biopsy or maximal tumor resection in atypical cases.

Simultaneous Mapping of Vasculature, Hypoxia, and Proliferation Using Dynamic Susceptibility Contrast MRI, 18F-FMISO PET, and 18F-FLT PET in Relation to Contrast Enhancement in Newly Diagnosed Glioblastoma.

Conventional MRI plays a key role in the management of patients with high-grade glioma, but multiparametric MRI and PET tracers could provide further information to better characterize tumor metabolism and heterogeneity by identifying regions having a high risk of recurrence. In this study, we focused on proliferation, hypervascularization, and hypoxia, all factors considered indicative of poor prognosis. They were assessed by measuring uptake of 18F-3'-deoxy-3'-18F-fluorothymidine (18F-FLT), relative cerebral blood volume (rCBV) maps, and uptake of 18F-fluoromisonidazole (18F-FMISO), respectively. For each modality, the volumes and high-uptake subvolumes (hot spots) were semiautomatically segmented and compared with the contrast enhancement (CE) volume on T1-weighted gadolinium-enhanced (T1w-Gd) images, commonly used in the management of patients with glioblastoma. Methods: Dynamic susceptibility contrast-enhanced MRI (31 patients), 18F-FLT PET (20 patients), or 18F-FMISO PET (20 patients), for a total of 31 patients, was performed on preoperative glioblastoma patients. Volumes and hot spots were segmented on SUV maps for 18F-FLT PET (using the fuzzy locally adaptive bayesian algorithm) and 18F-FMISO PET (using a mean contralateral image + 3.3 SDs) and on rCBV maps (using a mean contralateral image + 1.96 SDs) for dynamic susceptibility contrast-enhanced MRI and overlaid on T1w-Gd images. For each modality, the percentages of the peripheral volumes and the peripheral hot spots outside the CE volume were calculated. Results: All tumors showed highly proliferated, hypervascularized, and hypoxic regions. The images also showed pronounced heterogeneity of both tracers regarding their uptake and rCBV maps, within each individual patient. Overlaid volumes on T1w-Gd images showed that some proliferative, hypervascularized, and hypoxic regions extended beyond the CE volume but with marked differences between patients. The ranges of peripheral volume outside the CE volume were 1.6%-155.5%, 1.5%-89.5%, and 3.1%-78.0% for 18F-FLT, rCBV, and 18F-FMISO, respectively. All patients had hyperproliferative hot spots outside the CE volume, whereas hypervascularized and hypoxic hot spots were detected mainly within the enhancing region. Conclusion: Spatial analysis of multiparametric maps with segmented volumes and hot spots provides valuable information to optimize the management and treatment of patients with glioblastoma.

The role of indocyanine green fluorescence in endoscopic endonasal skull base surgery and its imaging correlations.

The use of endoscope-integrated indocyanine green (E-ICG) has recently been introduced in skull base surgery. The quantitative correlation between E-ICG and T1-weighted gadolinium-enhanced (T1WGd) images for skull base tumors has not been previously assessed, to the authors' knowledge. In this study, the authors investigated the indications for use and the limitations of E-ICG and sought to correlate the endoscopic fluorescence pattern with MRI contrast enhancement. Following IRB approval, 20 patients undergoing endoscopic endonasal skull base surgery between June 2017 and August 2018 were enrolled in the study. Tumor fluorescence was measured using a blue color value and blood fluorescence as a control. Signal intensities (SIs) of tumor T1WGd images were measured and the internal carotid artery (ICA) SI was used as a control. For pituitary adenoma, the pituitary gland fluorescence was also measured. The relationships between ICG fluorescence and MRI enhancement measurements were analyzed. Data showed that in pituitary adenoma there was a strong correlation between the ratios of gland/blood fluorescence to gland/ICA SI (n = 8; r = 0.92; p = 0.001) and tumor/blood fluorescence to tumor/ICA SI (n = 9; r = 0.82; p = 0.006). In other pathologies there was a strong correlation between the ratios of tumor/blood fluorescence and tumor/ICA SI (n = 9; r = 0.74; p = 0.022). The ICG fluorescence allowed perfusion assessment of the pituitary gland as well as of the nasoseptal flaps. Visualization of the surrounding vasculature was also feasible. Defining the indications and understanding the limitations are critical for the effective use of E-ICG. Tumor fluorescence seems to correlate with preoperative MRI contrast enhancement.

Improved detection of diffuse glioma infiltration with imaging combinations: a diagnostic accuracy study.

BackgroundSurgical resection and irradiation of diffuse glioma are guided by standard MRI: T2/fluid attenuated inversion recovery (FLAIR)–weighted MRI for non-enhancing and T1-weighted gadolinium-enhanced (T1G) MRI for enhancing gliomas. Amino acid PET has been suggested as the new standard. Imaging combinations may improve standard MRI and amino acid PET. The aim of the study was to determine the accuracy of imaging combinations to detect glioma infiltration.MethodsWe included 20 consecutive adults with newly diagnosed non-enhancing glioma (7 diffuse astrocytomas, isocitrate dehydrogenase [IDH] mutant; 1 oligodendroglioma, IDH mutant and 1p/19q codeleted; 1 glioblastoma IDH wildtype) or enhancing glioma (glioblastoma, 9 IDH wildtype and 2 IDH mutant). Standardized preoperative imaging (T1-, T2-, FLAIR-weighted, and T1G MRI, perfusion and diffusion MRI, MR spectroscopy and O-(2-[18F]-fluoroethyl)-L-tyrosine ([18F]FET) PET) was co-localized with multiregion stereotactic biopsies preceding resection. Tumor presence in the biopsies was assessed by 2 neuropathologists. Diagnostic accuracy was determined using receiver operating characteristic analysis.ResultsA total of 174 biopsies were obtained (63 from 9 non-enhancing and 111 from 11 enhancing gliomas), of which 129 contained tumor (50 from non-enhancing and 79 from enhancing gliomas). In enhancing gliomas, the combination of apparent diffusion coefficient (ADC) with [18F]FET PET (area under the curve [AUC], 95% CI: 0.89, 0.79‒0.99) detected tumor better than T1G MRI (0.56, 0.39‒0.72; P < 0.001) and [18F]FET PET (0.76, 0.66‒0.86; P = 0.001). In non-enhancing gliomas, no imaging combination detected tumor significantly better than standard MRI. FLAIR-weighted MRI had an AUC of 0.81 (0.65–0.98) compared with 0.69 (0.56–0.81; P = 0.019) for [18F]FET PET.ConclusionCombining ADC and [18F]FET PET detects glioma infiltration better than standard MRI and [18F]FET PET in enhancing gliomas, potentially enabling better guidance of local therapy.

Is fat suppression in T1 and T2 FSE with mDixon superior to the frequency selection-based SPAIR technique in musculoskeletal tumor imaging?

ObjectiveTo determine the image quality of fast spin echo (FSE) with mDixon relative to spectral attenuated inversion recovery (SPAIR) FSE sequences in musculoskeletal tumor imaging on a 1.5-T MRI system.Materials and methodsIn a HIPAA-compliant prospective study, 265 patients requiring musculoskeletal tumor MRI scans were included. Patient consent was waived by the medical ethical committee. Two radiologists compared SPAIR and mDixon FSE water-only images in both T2- and T1-weighted gadolinium-enhanced (T1-Gd) sequences using a five-point scale (paired samples t test and visual grading characteristics curves (VGC)). Homogeneity of fat suppression, noise, contrast, several artifacts (motion, phase, edge blurring and water–fat swap) and subjective preference were evaluated.ResultsReaders did not have subjective preference for either sequence in 71% and 55% (reader 1 and 2, respectively). Scores for homogeneous fat suppression were significantly (p < 0.01) higher for mDixon (4.88 in T2 and 4.87 in T1-Gd) than for SPAIR (4.31 for T2 and 4.21 for T1-Gd). All VGC curves for homogeneity demonstrated preference for mDixon. In 57 individual mDixon cases, fat-suppression homogeneity was strikingly better (≥ 2 points higher), namely in areas with field heterogeneity. Average noise and contrast scores were slightly higher for mDixon, as were motion artifact scores for SPAIR (< 0.5 points difference).ConclusionsmDixon fat suppression was significantly more homogeneous than SPAIR on both T2 and T1-Gd FSE images in musculoskeletal tumor protocols. In areas of field inhomogeneity, mDixon outperforms SPAIR. SPAIR had slightly less motion artifacts than mDixon.

Impact of Trajectory Planning With Susceptibility-Weighted Imaging for Intracranial Electrode Implantation.

While T1-weighted gadolinium-enhanced (T1-Gd) magnetic resonance imaging (MRI) is the standard imaging sequence for trajectory planning of stereotactic procedures, including deep brain stimulation, stereoelectroencephalography, and laser interstitial thermal therapy, susceptibility-weighted imaging (SWI) has been reported to demonstrate increased sensitivity for the visualization of microvasculature. To determine the impact of SWI visualization on trajectory planning for electrode implantation and evaluate the relationship between the rate of vessel-electrode intersections and intracerebral hemorrhage (ICH). We conducted a retrospective study of 13 patients who underwent stereoelectroencephalography and laser interstitial thermal therapy placement between 2014 and 2015, using their preoperative T1-Gd and SWI scans, and postoperative MRI scans to determine the rate of vessel-electrode intersections seen on the 2 imaging modalities, the mean diameter and depth of the vessels identified, and the rate of ICH after implantation. Among 13 patients, 106 electrodes were implanted. Sixty-three unique vessel-electrode intersections were identified on SWI with a mean of 4.85 intersections per patient. There were 13 intersections seen on T1-Gd with a mean of 1 intersection per patient. The intersected vessels visualized on SWI had a diameter of 1.49 ± 0.46 mm and those on T1-Gd were 2.01 ± 0.52 mm. There was no clear ICH observed in this series. SWI allows for improved visualization of the smaller, deep vessels, whereas T1-Gd adequately detects superficial, larger vessels. Despite the larger number of vessel-electrode intersections seen on SWI, no clear evidence of ICH was identified. Increased detection of deep vasculature does not appear to significantly benefit trajectory planning for stereotactic intracranial procedures and may limit the number of trajectories perceived to be safe.

Dynamics of FLAIR Volume Changes in Glioblastoma and Prediction of Survival.

The extent of tumor resection (EOTR) calculated by enhanced T1 changes in glioblastomas has been previously reported to predict survival. However, fluid-attenuated inversion recovery (FLAIR) volume may better represent tumor burden. In this study, we report the first assessment of the dynamics of FLAIR volume changes over time as a predictive variable for post-resection overall survival (OS). Contemporary data from 103 consecutive patients with complete imaging and clinical data who underwent resection of newly diagnosed glioblastoma followed by the Stupp protocol between 2010 and 2013 were analyzed. Clinical, radiographic, and outcome parameters were retrieved for each patient, including magnetic resonance imaging (MRI)-based volumetric tumor analysis before, immediately after, and 3months post-surgery. OS rate was 17.6months. A significant incremental OS advantage was noted, with as little as 85% T1-weighted gadolinium-enhanced (T1Gd)-EOTR measured on contrast-enhanced MRI. Pre- and immediate postoperative FLAIR-based EOTR was not predictive of OS; however, abnormal FLAIR volume measured 3months post-surgery correlated significantly with outcome when FLAIR residual tumor volume (RTV) was <19.3cm3 and <46% of baseline volume (p<0.0001 for both). Age and isocitrate dehydrogenase (IDH)-1 mutation were predictive of OS (p<0.0001, Cox proportional hazards). OS correlated with the immediate postoperative T1Gd-EOTR measured by enhanced T1 MRI, but not by FLAIR volume. Diminished abnormal FLAIR volume at 3months post-surgery was associated with OS benefit when FLAIR-RTV was <19.3cm3 or <46% of baseline. These threshold values provide a new radiological variable that can be used for prediction of OS in patients with glioblastoma immediately after completion of standard chemoradiation.

Contrast enhanced-magnetic resonance imaging as a surrogate to map verteporfin delivery in photodynamic therapy

The use of in vivo contrast-enhanced magnetic resonance (MR) imaging as a surrogate for photosensitizer (verteporfin) dosimetry in photodynamic therapy of pancreas cancer is demonstrated by correlating MR contrast uptake to ex vivo fluorescence images on excised tissue. An orthotopic pancreatic xenograft mouse model was used for the study. A strong correlation (r = 0.57) was found for bulk intensity measurements of T1-weighted gadolinium enhancement and verteporfin fluorescence in the tumor region of interest. The use of contrast-enhanced MR imaging shows promise as a method for treatment planning and photosensitizer dosimetry in human photodynamic therapy (PDT) of pancreas cancer.

Highlights of the European Society of Musculoskeletal Radiology (ESSR) annual meeting 2009

IntroductionThe 16th annual congress of the European Society ofMusculoskeletal Radiology (ESSR) took place in Genoa,Italy, on 12 and 13 June 2009. The meeting was held jointlywith the Italian Congress of Musculoskeletal Radiology,which took place on 11 June. A successful musculoskeletalultrasound course was also run in the afternoon of 11 June,organised by the society’s ultrasound subcommittee.Asusual,themeetingcomprisedarefreshercourse,which,this year, took the hip and bony pelvis as its theme, scientificsessions, special-focus sessions and a scientific e-posterexhibition. There were 688 delegates attending the ESSRmeeting, coming from right across Europe and beyond, while703 attended the Italian Society meeting. In total 181electronic posters were exhibited, and 49 scientific presenta-tions were made. The posters and presentations covered thewhole spectrum of musculoskeletal imaging, including noveltechnologies and techniques and new perspectives on well-recognisedconditions.Theabstractsofpaperspresentedatthemeeting appeared in the June 2009 edition of SkeletalRadiology [1]. This article attempts to highlight some ofthe presentations that might be of interest.Techniques and technologyAs might be expected, a number of papers focused onapplications for 3 T magnetic resonance (MR) imaging. Agroup from Munich published their first results of the use ofan isotropic three-dimensional (3D) turbo-spin echo (TSE)sequence for imaging the knee [2]. Total imaging time forthe sequence was in the order of 12.5 min, and the readersused 1 mm-thick multiplanar reconstructions for review.They found the 3D sequence images to be at leastcomparative with state-of-the-art two-dimensional (2D)sequences, but, of course, they had the advantage of beingable to undertake oblique reconstructions or review ofthinner slices. A group from Ireland and the Netherlandsshowed that 3 T magnetic resonance imaging (MRI) wasable to identify the double-bundle anatomy of the anteriorcruciate ligament (ACL) in 94% of patients in a retrospec-tive review of 50 patients with intact ACLs [3]; while theutility of 3 T MRI for evaluating upper limb nerve structureusing diffusion imaging and tractography was demonstratedby an Austrian group [4].In an interesting study looking at the effects of cartilageloading and unloading on T1-weighted gadolinium-enhanced(T1-Gd) relaxation times using the gadolinium-enhancedmagnetic resonance imaging of cartilage (dGEMRIC) tech-nique,workersshowedthatloadingarticularcartilagereducedthe mean T1-Gd relaxation time by approximately 50 ms [5].They emphasised that this needed to be considered when thedGEMRIC technique is to be used to assess glycosamino-glycan depletion in cartilage disease, which is also seen as areduction in T1-Gd relaxation time.A study from Switzerland looked at the use of advancedMRI techniques for the diagnosis and prediction ofoutcome in patients with Perthes’ disease [6]. They useddiffusion-weighted MRI and dynamic gadolinium-enhancedsubtraction techniques, comparing them with pinholescintigraphy. They identified increased apparent diffusioncoefficients (ADCs) in the femoral epiphyses as beingsensitive and specific for the diagnosis, but they found that