Contrast‐Enhanced Fluid‐Attenuated Inversion Recovery in Neuroimaging: A Narrative Review on Clinical Applications and Technical Advances

Han

Journal of Neurosurgery

et al. 2023

OBJECTIVE Leptomeningeal metastases (LMs) in glioma have been underestimated given their low incidence and the lack of reliable imaging. Authors of this study aimed to investigate the real-world incidence of LMs using cerebrospinal fluid (CSF)–sensitive imaging, namely postcontrast fluid-attenuated inversion recovery (FLAIR) imaging, and to analyze molecular predictors for LMs in the molecular era. METHODS A total of 1405 adult glioma (World Health Organization [WHO] grade 2–4) patients underwent postcontrast FLAIR imaging at initial diagnosis and during treatment monitoring between 2001 and 2021. Collected molecular data included isocitrate dehydrogenase (IDH) mutation, 1p/19q codeletion, H3 K27 alteration, and O6-methylguanine–DNA methyltransferase (MGMT) promoter methylation status. LM diagnosis was performed with MRI including postcontrast FLAIR sequences. Logistic regression analysis for LM development was performed with molecular, clinical, and imaging data. Overall survival (OS) was compared between patients with and those without LM. RESULTS LM was identified in 228 patients (16.2%), 110 (7.8%) at the initial diagnosis and 118 (8.4%) at recurrence. Among the molecular diagnostics, IDH-wildtype (OR 3.14, p = 0.001) and MGMT promoter unmethylation (OR 1.43, p = 0.034) were independent predictors of LM. WHO grade 4 (OR 10.52, p < 0.001) and nonlobar location (OR 1.56, p = 0.048) were associated with LM at initial diagnosis, whereas IDH-wildtype (OR 5.04, p < 0.001) and H3 K27 alteration (OR 3.39, p = 0.003) were associated with LM at recurrence. Patients with LM had a worse median OS than those without LM (16.7 vs 32.0 months, p < 0.001, log-rank test), which was confirmed as an independent factor on multivariable Cox analysis (p = 0.004). CONCLUSIONS CSF-sensitive imaging aids the diagnosis of LM, demonstrating a high incidence of LM in adult gliomas. Furthermore, molecular markers are associated with LM development in glioma, and patients with aggressive molecular markers warrant imaging surveillance for LM.

Section: Discussionmentioning

confidence: 99%

Leptomeningeal metastases in glioma revisited: incidence and molecular predictors based on postcontrast fluid-attenuated inversion recovery imaging

Han

Journal of Neurosurgery

et al. 2023

“…Post-contrast FLAIR is known to have superior performance than post-contrast T1 gradient echo images in the detection of LM. 7,8,30 FLAIR effectively suppresses the normal vasculature of the leptomeninges, which can be confused with abnormal leptomeningeal enhancement in post-contrast T1 gradient echo imaging. Currently, post-contrast FLAIR is not a routinely recommended sequence in glioma MRI protocol 10 and the e cacy of post-contrast FLAIR in LM detection has not been studied in glioma patients.…”

Section: Discussionmentioning

confidence: 99%

“…The markedly lower incidence of LM reported on clinical studies compared to autopsy results is due to the lack of imaging dedicated for LM diagnosis. 7 Post-contrast uid attenuated inversion recovery (FLAIR), namely CSF-sensitive, imaging has shown superior performance of LM detection in brain metastases patients, 7,8 and the EANO-ESMO guideline recommends routine inclusion of post-contrast FLAIR to diagnose LM in patients with solid tumors. 9 However, post-contrast FLAIR is not a routinely recommend sequence in glioma MRI protocol, 10 and the e cacy of post-contrast FLAIR in LM detection has not been studied in a large cohort of glioma patients.…”

Section: Introductionmentioning

confidence: 99%

Leptomeningeal Metastases in Glioma Revisited: Incidence and Molecular Predictors Based on Post-contrast FLAIR Imaging

Han

Park³

et al. 2022

Preprint

Background: Leptomeningeal metastases (LM) in glioma have been underestimated due to low incidence and lack of reliable imaging. This study aimed to investigate a real-world incidence of LM using a CSF-sensitive imaging, namely post-contrast FLAIR, and analyze molecular predictors for LM in the molecular era. Patients and Methods: Total 1,405 adult glioma patients underwent post-contrast FLAIR imaging at initial diagnosis and during treatment monitoring between 2001 and 2021. Molecular data included isocitrate dehydrogenase (IDH) mutation, 1p/19q co-deletion, H3 K27M alteration, and O6-methylguanine-methyltransferase (MGMT) promoter methylation status. LM diagnosis was performed with MRI including post-contrast FLAIR. Logistic regression analysis for LM development was performed with molecular, clinical, and imaging data. Overall survival (OS) was compared between patients with and without LM. Results: LM was identified in 228 patients (16.2%), with 110 patients (7.8%) at initial diagnosis, and 118 patients (8.4%) at recurrence. Among molecular diagnostics, IDH-wildtype (odds ratio [OR] 3.14, P = .001) and MGMT promoter unmethylation (OR=1.43, P=.034) were independent predictors of LM. WHO grade 4 (OR=10.52, P <.001) and nonlobar location (OR=1.54, P=.048) were associated with LM at initial diagnosis, whereas IDH-wildtype (OR=5.04, P<.001) and H3 K27M alteration (OR=3.39, P=.003) were associated with LM at recurrence. Patients with LM had a worse median OS than those without LM (16.7 vs. 32.0 months, log-rank test; P<.001). Conclusions: CSF-sensitive imaging aid diagnosis of LM demonstrating a high incidence of LM in adult gliomas. Furthermore, molecular markers are associated with LM development in glioma, and patients with aggressive molecular markers warrant imaging surveillance of LM.

“…Fluid attenuated inversion recovery is a special inversion recovery pulse sequence that can effectively display the area of T2 extension and suppress the cerebral spinal fluid (CSF) signal ( Ahn et al, 2022 ). Additionally, contrast-enhanced FLAIR may provide information that is not available in T1-weighted contrast-enhanced MRI for detecting brain diseases, and its imaging principle is closely related to the disruption of central nervous system barrier structures ( Ahn et al, 2022 ). In SAE, disrupted BBB may cause contrast agents to leak from the blood and be diluted by the surrounding liquid ( Figure 1 ).…”

Section: Principles and Applications Of Mri-related Techniques In Sae...mentioning

confidence: 99%

Application of magnetic resonance imaging-related techniques in the diagnosis of sepsis-associated encephalopathy: present status and prospect

Wang

Song

et al. 2023

Front. Neurosci.

Sepsis-associated encephalopathy (SAE) refers to diffuse brain dysfunction secondary to systemic infection without central nervous system infection. The early diagnosis of SAE remains a major clinical problem, and its diagnosis is still exclusionary. Magnetic resonance imaging (MRI) related techniques, such as magnetic resonance spectroscopy (MRS), molecular MRI (mMRI), arterial spin-labeling (ASL), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI), currently provide new options for the early identification of SAE. This review collected clinical and basic research and case reports related to SAE and MRI-related techniques in recent years, summarized and analyzed the basic principles and applications of MRI technology in diagnosing SAE, and provided a basis for diagnosing SAE by MRI-related techniques.