Interrater Agreement of BT-RADS for Evaluation of Follow-Up MRI in Treated Primary Brain Tumor Patients.

BACKGROUND AND PURPOSE: The Brain Tumor Reporting and Data System (BT-RADS) is a structured radiology reporting algorithm that was introduced to provide uniformity in post-treatment primary brain tumor follow-up and reporting, but its interrater reliability (IRR) assessment has not been widely studied. Our goal is to evaluate the IRR among neuroradiologists and radiology residents in the use of BT-RADS. MATERIALS AND METHODS: This retrospective study reviewed 103 consecutive MR studies in 98 adult patients previously diagnosed with and treated for primary brain tumor (January 2019 to February 2019). Six readers with varied experience (4 neuroradiologists and 2 radiology residents) independently evaluated each case and assigned a BT-RADS score. Readers were blinded to the original score reports and the reports from other readers. Cases in which at least one neuroradiologist scored differently were subjected to consensus scoring. After the study, a post-hoc reference score was also assigned by 2 readers using future imaging and clinical information previously unavailable to readers. The interrater reliabilities were assessed using Gwet's AC2 index with ordinal weights and percent agreement. RESULTS: Of the 98 patients evaluated (median age, 53 years; interquartile range, 41-66 years), 53% were males. The most common tumor type was astrocytoma (77%) of which 56% were grade 4 glioblastoma. Gwet's index for interrater reliability among all six readers was 0.83 (95% CI: 0.78, 0.87). The Gwet's index for the neuroradiologists' group (0.84 [95% CI: 0.79, 0.89]) was not statistically different from that for the residents' group (0.79 [95% CI: 0.72, 0.86]) (χ2 = 0.85; p = 0.36). All four neuroradiologists agreed on the same BT-RADS score in 57 of the 103 studies, three neuroradiologists agreed in 21 of the 103 studies, and two neuroradiologists agreed in 21 of the 103 studies. Percent agreement between neuroradiologist blinded scores and post-hoc reference scores ranged from 41%-52%. CONCLUSIONS: A very good interrater agreement was found when tumor reports were interpreted by independent blinded readers using BT-RADS criteria. Further study is needed to determine if this high overall agreement can translate into greater consistency in clinical care. ABBREVIATIONS: BI-RADS = Breast Imaging Reporting and Data System; BT-RADS = Brain Tumor Reporting and Data System; IQR = interquartile range; IRR = interrater reliability; NI-RADS = Neck Imaging Reporting and Data System.

Using Brain Tumor MRI Structured Reporting to Quantify the Impact of Imaging on Brain Tumor Boards.

Multidisciplinary tumor boards (TB) are an essential part of brain tumor care, but quantifying the impact of imaging on patient management is challenging due to treatment complexity and a lack of quantitative outcome measures. This work uses a structured reporting system for classifying brain tumor MRIs, the brain tumor reporting and data system (BT-RADS), in a TB setting to prospectively assess the impact of imaging review on patient management. Published criteria were used to prospectively assign three separate BT-RADS scores (an initial radiology report, secondary TB presenter review, and TB consensus) to brain MRIs reviewed at an adult brain TB. Clinical recommendations at TB were noted and management changes within 90 days after TB were determined by chart review. In total, 212 MRIs in 130 patients (median age = 57 years) were reviewed. Agreement was 82.2% between report and presenter, 79.0% between report and consensus, and 90.1% between presenter and consensus. Rates of management change increased with increasing BT-RADS scores (0-3.1%, 1a-0%, 1b-66.7%, 2-8.3%, 3a-38.5%, 3b-55.9, 3c-92.0%, and 4-95.6%). Of 184 (86.8%) cases with clinical follow-up within 90 days after the tumor board, 155 (84.2%) of the recommendations were implemented. Structured scoring of MRIs provides a quantitative way to assess rates of agreement interpretation alongside how often management changes are recommended and implemented in a TB setting.

Cranial nerve abnormalities in spontaneous intracranial hypotension and their clinical relevance.

BACKGROUND AND PURPOSE: Spontaneous intracranial hypotension (SIH) is a known cause of headaches and neurologic symptoms, but the frequency of cranial nerve symptoms and abnormalities on magnetic resonance imaging (MRI) has not been well described. The purpose of this study was to document cranial nerve findings in patients with SIH and determine the relationship between imaging findings and clinical symptoms. METHODS: Patients diagnosed with SIH with pre-treatment brain MRI at a single institution from September 2014 to July 2017 were retrospectively reviewed to determine the frequency of clinically significant visual changes/diplopia (cranial nerves 3 and 6) and hearing changes/vertigo (cranial nerve 8). A blinded review of brain MRIs before and after treatment was conducted to assess for abnormal contrast enhancement of cranial nerves 3, 6, and 8. Imaging results were correlated with clinical symptoms. RESULTS: Thirty SIH patients with pre-treatment brain MRI were identified. Sixty-six percent of patients had vision changes, diplopia, hearing changes, and/or vertigo. Cranial nerve 3 and/or 6 enhancement was present in nine patients on MRI, with 7/9 patients experiencing visual changes and/or diplopia (odds ratio [OR] 14.9, 95% confidence interval [CI] 2.2-100.8, p = .006). Cranial nerve 8 enhancement was present in 20 patients on MRI, with 13/20 patients experiencing hearing changes and/or vertigo (OR 16.7, 95% CI 1.7-160.6, p = .015). CONCLUSIONS: SIH patients with cranial nerve findings on MRI were more likely to have associated neurologic symptoms than those without imaging findings. Cranial nerve abnormalities on brain MRI should be reported in suspected SIH patients as they may support the diagnosis and explain patient symptoms.

A brain tumor reporting and data system to optimize imaging surveillance and prognostication in high-grade gliomas.

BACKGROUND AND PURPOSE: High-grade glioma (HGG), including glioblastoma, is the most common primary brain neoplasm and has a dismal prognosis. After initial treatment, follow-up decisions are guided by longitudinal MRI performed at routine intervals. The Brain Tumor Reporting and Data System (BT-RADS) is a proposed structured reporting system for posttreatment brain MRIs. The purpose of this study is to determine the relationship between BT-RADS scores and overall survival in HGG patients. METHODS: Chart review of grade 4 glioma patients who had an MRI at a single institution from November 2018 to November 2019 was performed. BT-RADS scores, tumor characteristics, and overall survival were recorded. Likelihood of improvement, stability, or worsening on the subsequent study was calculated for each score. Survival analysis was performed using Kaplan-Meier method, log-rank test, and a time-dependent cox model. Significance level of .05 was used. RESULTS: The study identified 91 HGG patients who underwent a total of 538 MRIs. Mean age of patients was 57 years old. Score with the highest likelihood for worsening on the next follow-up was 3b. The risk of death was 53% higher with each incremental increase in BT-RADS scores (hazard ratio, 1.53; 95% confidence interval [CI], 1.07-2.19; p = .019). The risk of death was 167% higher in O-6-methylguanine-DNA-methyltransferase unmethylated tumors (hazard ratio, 2.67; 95% CI, 1.34-5.33; p = .005). CONCLUSIONS: BT-RADS scores can be used as a reference guide to anticipate whether patients' subsequent MRI will be improved, stable, or worsened. The scoring system can also be used to predict clinical outcomes and prognosis.

MRI-Visible Anatomy of the Basal Ganglia and Thalamus.

Conventional MR imaging does not discriminate basal ganglia and thalamic internal anatomy well. Radiology reports describe anatomic locations but not specific functional structures. Functional neurosurgery uses indirect targeting based on commissural coordinates or atlases that do not fully account for individual variability. We describe innovative MR imaging sequences that improve the visualization of normal anatomy in this complex brain region and may increase our understanding of basal ganglia and thalamic function. Better visualization also may improve treatments for movement disorders and other emerging functional neurosurgery targets. We aim to provide an accessible review of the most clinically-relevant neuroanatomy within the thalamus and basal ganglia.

MRI-Visible Anatomy of the Brainstem.

Human brainstem internal anatomy is intricate, complex, and essential to normal brain function. The brainstem is affected by stroke, multiple sclerosis, and most neurodegenerative diseases-a 1-mm focus of pathologic condition can have profound clinical consequences. Unfortunately, detailed internal brainstem anatomy is difficult to see with conventional MRI sequences. We review normal brainstem anatomy visualized on widely available clinical 3-T MRI scanners using fast gray matter acquisition T1 inversion recovery, probabilistic diffusion tractography, neuromelanin, and susceptibility-weighted imaging. Better anatomic localization using these recent innovations improves our ability to diagnose, localize, and treat brainstem diseases. We aim to provide an accessible review of the most clinically relevant brainstem neuroanatomy.

Application of Diffusion Weighted Imaging and Diffusion Tensor Imaging in the Pretreatment and Post-treatment of Brain Tumor.

Diffusion MR imaging exploits the diffusion properties of water to generate contrast between normal tissue and pathology. Diffusion is an essential component of nearly all brain tumor MR imaging examinations. This review covers the important clinical applications of diffusion weighted imaging in the pretreatment diagnosis and grading of brain tumors and assessment of treatment response. Diffusion imaging improves the accuracy of identifying treatment-related effects that may mimic tumor improvement or worsening. Fiber tractography models of eloquent white matter pathways are generated using diffusion tensor imaging. A practical and concise tractography guide is provided for anyone new to preoperative surgical mapping.

Hirayama-like disease in the thoracic spine.

Hirayama disease is a cervical flexion myelopathy that typically causes upper extremity weakness in young male patients. We present two male patients (age 15 and 29) with MRI findings of thoracic ligamentous laxity similar in appearance to Hirayama disease. However, patients presented with atypical symptoms, specifically back pain and paresthesia of the upper and/or lower extremities, likely correlating to the abnormal thoracic spinal levels involved. Flexion/extension MRI sequences demonstrated the forward displacement of the dorsal dura and compression the thoracic cord with prominence of the posterior epidural space and venous plexus. Follow-up MRAs were negative for a spinal vascular malformation. Patients were managed conservatively with no surgical intervention. Clinical history, thoracic MRI, and follow-up flexion and angiographic imaging sequences may help confirm a diagnosis of Hirayama-like thoracic ligamentous laxity.

A comprehensive data-driven analysis framework for detecting impairments in brain function networks with resting state fMRI in HIV-infected individuals on cART.

Central nervous system (CNS) sequelae continue to be common in HIV-infected individuals despite combination antiretroviral therapy (cART). These sequelae include HIV-associated neurocognitive disorder (HAND) and virologic persistence in the CNS. Resting state functional magnetic resonance imaging (rsfMRI) is a widely used tool to examine the integrity of brain function and pathology. In this study, we examined 16 HIV-positive (HIV+) subjects and 12 age, sex, and race matched HIV seronegative controls (HIV-) whole-brain high-resolution rsfMRI along with a battery of neurocognitive tests. A comprehensive data-driven analysis of rsfMRI revealed impaired functional connectivity, with very large effect sizes in executive function, language, and multisensory processing networks in HIV+ subjects. These results indicate the potential of high-resolution rsfMRI in combination with advanced data analysis techniques to yield biomarkers of neural impairment in HIV.

Reduced gray-white matter contrast localizes the motor cortex on double inversion recovery (DIR) 3T MRI.

PURPOSE: Reduced gray-white matter contrast along the central sulcus has been described on T1- and T2-weighted magnetic resonance imaging (MRI). The purpose of this study was to assess the gray-white matter contrast of the motor cortex on double inversion recovery (DIR), a sequence with superior gray-white matter differentiation. METHODS: The gray-white matter signal on DIR was retrospectively compared to T1-weighted magnetization-prepared rapid gradient echo (T1-MPRAGE) using normal (n = 25) and abnormal (n = 25) functional MRI (fMRI) exams. Quantitative gray-white matter contrast ratios (CR) of the precentral and adjacent gyri were obtained on normal exams. Two neuroradiologists qualitatively rated reduced gray-white matter contrast of the hemispheres of both normal and abnormal exams. Hand motor functional mapping was used as a reference. RESULTS: In normal hemispheres (n = 50), the mean CR was significantly lower on DIR (0.44) vs T1-MPRAGE (0.63, p < 0.001). Reduced gray-white matter contrast was categorized as "definitely present" more frequently on DIR than T1-MPRAGE by reviewers in both normal (n = 50; reviewer 1 DIR 88% and MPRAGE 68%, p = 0.02; reviewer 2 DIR 86% and T1-MPRAGE 64%; p=0.01) and abnormal hemispheres (n = 50; reviewer 1 DIR 80% and T1-MPRAGE 38%, p < 0.001; reviewer 2 DIR 74% and T1-MPRAGE 46%, p = 0.005). CONCLUSION: Reduced gray-white matter contrast of the motor cortex is more pronounced on DIR compared to T1-MPRAGE on quantitative and qualitative assessments of normal MRI exams. In abnormal cases, reviewers more definitively identified the motor cortex on DIR. In cases with distorted brain anatomy, DIR may be a useful adjunct sequence to localize the motor cortex.

Using a Website to Teach a Structured Reporting System, the Brain Tumor Reporting and Data System.

BACKGROUND: The Brain Tumor Reporting and Data System (BT-RADS) is a proposed standardized radiology reporting scheme for magnetic resonance imagings in brain tumor patients. A website was created to introduce the classification system and to promote its use during daily radiology readouts with trainees. OBJECTIVES: To demonstrate how a website can help implement a structured reporting at a tertiary academic facility. METHODS: A website, www.btrads.com, including visual aids and an interactive scoring tool was developed to educate trainees about a structured reporting system for brain tumor magnetic resonance imagings. Number of website visitors, resource downloads, and scoring tool users was gathered during the study period of May 1, 2018 to April 30, 2019. Authors surveyed a group of 71 radiology trainees and 34 faculty physicians who care for brain tumor patients to assess the perceived educational and clinical value of BT-RADS. RESULTS: The website was visited by 10,058 unique users in 1 year. The most commonly downloaded support material was the full guide (382 downloads). The interactive scoring tool was used 267 times. The use of BT-RADS at a single institution over 12 months reached over 70%. While survey results from trainees did not reach statistical significance, faculty oncologists, neurosurgeons, and radiologists felt that BT-RADS was a valuable clinical tool that improved interdisciplinary communication, facilitated educational discussions, and helped make treatment decisions. CONCLUSIONS: A website designed to implement a novel structured radiology report facilitated template acceptance across a large neuroradiology section. Groups seeking to modify reporting practices should consider using a website.

Malignant seeding of the biopsy needle tract outside of the radiation therapy field in a patient with Glioblastoma.

A 44-year-old male initially presented with a right thalamic brain tumor that was confirmed with stereotactic biopsy to be glioblastoma (GBM). The patient was treated with radiotherapy and temozolomide for 6 weeks. At 1 month after completing chemoradiation therapy, the patient underwent follow-up imaging that revealed the primary lesion had mildly responded to chemoradiation, but a secondary lesion had developed along the biopsy needle tract. This secondary lesion was outside of the field of radiation therapy for the primary tumor and concluded to be intracranial spread of GBM along the biopsy tract. The patient's final imaging 4 months after initial diagnosis revealed the primary and secondary lesions had enlarged. Subsequently, the patient clinically deteriorated and died 7 months after initial diagnosis.

Inner SPACE: 400-Micron Isotropic Resolution MRI of the Human Brain.

OBJECTIVES: Clinically relevant neuroanatomy is challenging to teach, learn and remember since many functionally important structures are visualized best using histology stains from serial 2D planar sections of the brain. In clinical patients, the locations of specific structures then must be inferred from spatial position and surface anatomy. A 3D MRI dataset of neuroanatomy has several advantages including simultaneous multi-planar visualization in the same brain, direct end-user manipulation of the data and image contrast identical to clinical MRI. We created 3D MRI datasets of the postmortem brain with high spatial and contrast resolution for simultaneous multi-planar visualization of complex neuroanatomy. MATERIALS AND METHODS: Whole human brains (N = 6) were immersion-fixed in 4% formaldehyde for 4 weeks, then washed continuously in water for 48 h. The brains were imaged on a clinical 3-T MRI scanner with a 64-channel head and neck coil using a 3D T2-weighted sequence with 400-micron isotropic resolution (voxel = 0.064 mm3; time = 7 h). Besides resolution, this sequence has multiple adjustments to improve contrast compared to a clinical protocol, including 93% reduced turbo factor and 77% reduced effective echo time. RESULTS: This MRI microscopy protocol provided excellent contrast resolution of small nuclei and internal myelinated pathways within the basal ganglia, thalamus, brainstem, and cerebellum. Contrast was sufficient to visualize the presence and variation of horizontal layers in the cerebral cortex. 3D isotropic resolution datasets facilitated simultaneous multi-planar visualization and efficient production of specific tailored oblique image orientations to improve understanding of complex neuroanatomy. CONCLUSION: We created an unlabeled high-resolution digital 3D MRI dataset of neuroanatomy as an online resource for readers to download, manipulate, annotate and use for clinical practice, research, and teaching that is complementary to traditional histology-based atlases. Digital MRI contrast is quantifiable, reproducible across brains and could help validate novel MRI strategies for in vivo structure visualization.

CT Myelography: Clinical Indications and Imaging Findings.

CT myelography is an important imaging modality that combines the advantages of myelography and the high resolution of CT. It provides a detailed delineation of pathologic spine conditions, especially those involving the thecal sac and its contents. However, the role of CT myelography has dramatically and appropriately decreased with the advent of MRI, which provides a noninvasive method to demonstrate pathologic spine conditions with high signal intensity in soft tissues. At the present time, CT myelography is often performed in patients who require evaluation of the thecal sac but have a contraindication to undergoing MRI. However, there remain many situations in which CT myelography is indicated and plays a critical role in patient treatment. The authors review common and uncommon indications for CT myelography and demonstrate various pathologic conditions in which CT myelography plays a vital role in patient treatment in this modern era of MRI.©RSNA, 2020.

Quantitative Improvement in Brain Tumor MRI Through Structured Reporting (BT-RADS).

RATIONALE AND OBJECTIVES: Determine the objective benefits of structured reporting of brain tumors through Brain tumor-RADS (BT-RADS) by analyzing discrete quantifiable metrics of the reports themselves. MATERIALS AND METHODS: Following Institutional Review Board approval, post-treatment glioma reports were acquired from two matched 3-month time periods for pre- and postimplementation of BT-RADS. The reports were analyzed for presence of history words, such as "Avastin" and "methylguanine-DNA methyltransferase," as well as hedge words, such as "Possibly" and "Likely." The word counts of the total report and of the impression section were also assessed, as well as whether or not the report contained addenda. RESULTS: In total, 211 pre-BT-RADS and 172 post-BT-RADS reports were analyzed. Post-BT-RADS reports demonstrated greater reporting of history words, including "Avastin" (7.6% vs. 20.9%, p < 0.001) and "methylguanine-DNA methyltransferase" (10.9% vs. 31.4%, p < 0.0001). They also demonstrated reduced usage of hedge words, including "Possibly" (3.8% vs. 0.6%, p < 0.05) and "Likely" (49.8% vs. 28.5%, p < 0.01). Furthermore, post-BT-RADS reports possessed fewer words in total report length (389 vs. 245.2, p < 0.001), as well as in the impression section (53.7 vs. 42.6, p < 0.01). Finally, fewer post-BT-RADS reports contained addenda (10% vs. 1.2%, p < 0.01). CONCLUSION: Following implementation of BT-RADS, glioma reports demonstrated greater consistency and completeness of clinical history, less ambiguity, and more conciseness.

Appearance of cerebral infarct fogging on CT perfusion.

Fogging is a deceptive phenomenon that can partially or completely obscure a subacute infarct on noncontrast head CT. We present the appearance of infarct fogging on CT perfusion through 3 cases. At time of fogging, the subacute infarctions demonstrated variable mean transit time with increased cerebral blood volume and cerebral blood flow on CT perfusion. Fogging occurred within 6-10 days, sooner than the previously described 2-3 weeks in classic fogging. At time of fogging, CT perfusion demonstrated a "luxury-like" perfusion pattern and augmented the identification of the true extent of the infarction at time of fogging.

Combined task activation display as an effective method to teach introductory fMRI users.

RATIONALE AND OBJECTIVES: Interpreting functional magnetic resonance imaging (fMRI) can be an overwhelming and challenging task for trainees, particularly when post processing, synthesizing and interpreting data from multiple language paradigms. Currently, there is no established best method for teaching fMRI interpretation to new trainees. The purpose of our study is to compare the use of combined task activation display (CTAD) and conventional display of fMRI language paradigms as an effective method to teach fMRI to the introductory learner. MATERIALS AND METHODS: Following IRB approval, 43 unique cases (with 10 repeat cases to assess intra-reader variability) were identified based on the inclusion/exclusion criteria. Eight radiology trainees, without prior exposure to fMRI, were asked to determine language lateralization based on activation of Wernicke's area, Broca's area, and the pre-supplementary motor area. Prior to trainee interpretation, a 15-minute training session was conducted to describe the expected anatomic locations of the language centers. Trainees were asked to determine language dominance using either the CTAD or conventional methods. Following a 6-week washout period, the same eight trainees were asked to interpret the cases using the opposite interpretation approach. RESULTS: Interpreting fMRI with the CTAD method significantly increased trainee accuracy (85.4% vs 70.9% p < 0.001) and trainee confidence (4.3 vs 3.6 p < 0.001), while decreasing time to interpretation (mean difference of 29 min), and intra-reader variability when compared to the conventional approach. CONCLUSION: Combined task activation display is an effective method to teach fMRI to introductory learners.

Combined Use of Diffusion Tractography and Advanced Intraoperative Imaging for Resection of Cervical Intramedullary Spinal Cord Neoplasms: A Case Series and Technical Note.

BACKGROUND: Intramedullary spinal cord neoplasms (ISCN) pose significant management challenges. Advances in magnetic resonance imaging (MRI) (such as diffusion tensor imaging, DTI) have been utilized to determine the infiltrative nature and resectability of ISCN. However, this has not been applied to intraoperative decision making. OBJECTIVE: To present a case series of 2 patients with ISCN, the first to combine use of DTI, pre- and intraoperative 3-dimensional (3D) virtual reality imaging, and microscope integrated navigation with heads-up display. METHODS: Two patients who underwent surgery for ISCN were included. DTI images were obtained and 3D images were created using Surgical Theater (Surgical Theater SRP, Version 7.4.0, Cleveland, Ohio). Fiducials were used to achieve accurate surface registration to C4. Navigation confirmed the levels of laminectomy necessary. The microscope was integrated with Brainlab (Brainlab AG Version 3.0.5, Feldkirchen, Germany) and the tumor projected in the heads-up display. Surgical Theater was integrated with Brainlab to allow for real time evaluation of the 3D tractography. RESULTS: Case 1: All tracts were pushed away from the tumor, suggesting it was not infiltrative. Surgical Theater and Brainlab assisted in confirming midline despite the abnormal swelling of the cord so the myelotomy could be performed. The heads-up display outline demonstrated excellent correlation to the tumor. Gross total resection was achieved. Diagnosis of ependymoma was confirmed. Case 2: Some tracts were going through the tumor itself, suggesting an infiltrative process. Surgical Theater and Brainlab again allowed for confirmation of the midline raphe. Near total resection of the enhancing portion was achieved. Diagnosis of glioblastoma was confirmed. CONCLUSION: This is a proof of concept application where multi-modal imaging technology was utilized for safest maximal ISCN resection.

Glioblastoma with brainstem leptomeningeal pseudoprogression following radiation therapy.

In brain tumor patients, worsening of imaging findings in the first 6 months after surgical debulking and chemoradiation can occur in the absence of tumor growth, a phenomenon known as pseudoprogression. Awareness of pseudoprogression is important as it can lead to unnecessary additional changes in patient management. In this case, a patient with bilateral frontal glioblastoma presented with new post-treatment brainstem leptomeningeal enhancement which was distant from the original tumor site, concerning for disease progression. However, the patient was asymptomatic and correlation of leptomeningeal enhancement locations with radiation therapy dose maps revealed high doses at the affected site, supporting a diagnosis of treatment effect which was confirmed by resolution on follow-up imaging after treatment with steroids. Parenchymal pseudoprogression in brain tumor patients is well-documented, but worsening leptomeningeal enhancement following therapy may also represent treatment effects. If spatially remote leptomeningeal enhancement occurs, correlation with radiation dose maps may be useful in suggesting a diagnosis of treatment effect over tumor progression.