Evaluating the Efficacy of Perfusion MRI and Conventional MRI in Distinguishing Recurrent Cerebral Metastasis from Brain Radiation Necrosis.

Differentiating recurrent cerebral metastasis (CM) from brain radiation necrosis (BRN) is pivotal for guiding appropriate treatment and prognostication. Despite advances in imaging techniques, however, accurately distinguishing these conditions non-invasively is still challenging. This single-center retrospective study reviewed 32 cases (28 patients) with confirmed cerebral metastases who underwent surgical excision of lesions initially diagnosed by MRI and/or MR perfusion scans from 1 January 2015 to 30 September 2020. Diagnostic accuracy was assessed by comparing imaging findings with postoperative histopathology. Conventional MRI accurately identified recurrent CM in 75% of cases. MR perfusion scans showed significantly higher mean maximum relative cerebral blood volume (max. rCBV) in metastasis cases, indicating its potential as a discriminative biomarker. No single imaging modality could definitively distinguish CM from BRN. Survival analysis revealed gender as the only significant factor affecting overall survival, with no significant survival difference observed between patients with CM and BRN after controlling for confounding factors. This study underscores the limitations of both conventional MRI and MR perfusion scans in differentiating recurrent CM from BRN. Histopathological examination remains essential for accurate diagnosis. Further research is needed to improve the reliability of non-invasive imaging and to guide the management of patients with these post-radiation events.

Virtual magnetic resonance elastography predicts the intraoperative consistency of meningiomas.

BACKGROUND AND PURPOSE: Virtual magnetic resonance elastography (vMRE) is an experimental imaging modality designed to non-invasively predict the haptic properties of tissues. The modality is sensitive to tissue stiffness and fibrosis. Information about meningioma consistency prior to resection is of great interest in neurological surgery as the surgical plan and outcome may be affected by the tumor's stiffness. In this study, we assessed the ability of vMRE to predict the intraoperative consistency and mechanical heterogeneity of intracranial meningiomas. MATERIALS AND METHODS: We included 12 patients scheduled for meningioma resection, of which one patient was found to have a solitary fibrous tumor on histological examination. All participants underwent preoperative vMRE and intraoperative consistency grading. RESULTS AND CONCLUSIONS: Intraoperative qualitative consistency correlated positively with vMRE-based consistency assessment (odds ratio 5.63, 95% CI 1.12-28.30, p = 0.04) at b1000. Mechanically homogenous tumors had significantly lower ∆ mean stiffness than heterogeneous tumors (8.13 vs 18.07 kPa, p = 0.01). This study thus demonstrates a possible clinical application of vMRE in predicting the intraoperative consistency and mechanical heterogeneity of meningiomas.

Magnetic Resonance Elastography in Intracranial Neoplasms: A Scoping Review.

BACKGROUND: Magnetic resonance elastography (MRE) allows noninvasive assessment of intracranial tumor mechanics and may thus be predictive of intraoperative conditions. Variations in the use of technical terms complicate reading of current literature, and there is need of a review using consolidated nomenclature. OBJECTIVES: We present an overview of current literature on MRE relating to human intracranial neoplasms using standardized nomenclature suggested by the MRE guidelines committee. We then discuss the implications of the findings, and suggest approaches for future research. METHOD: We performed a systematic literature search in PubMed, Embase, and Web of Science; the articles were screened for relevance and then subjected to full text review. Technical terms were consolidated. RESULTS: We identified 12 studies on MRE in patients with intracranial tumors, including meningiomas, glial tumors including glioblastomas, vestibular schwannomas, hemangiopericytoma, central nervous system lymphoma, pituitary macroadenomas, and brain metastases. The studies had varying objectives that included prediction of intraoperative consistency, histological separation, prediction of adhesiveness, and exploration of the mechanobiology of tumor invasiveness and malignancy. The technical terms were translated using standardized nomenclature. The literature was highly heterogeneous in terms of image acquisition techniques, post-processing, and study design and was generally limited by small and variable cohorts. CONCLUSIONS: MRE shows potential in predicting tumor consistency, adhesion, and mechanical homogeneity. Furthermore, MRE provides insight into malignant tumor behavior and its relation to tissue mechanics. MRE is still at a preclinical stage, but technical advances, improved understanding of soft tissue rheological impact, and larger samples are likely to enable future clinical introduction.

Magnetic resonance elastography in normal pressure hydrocephalus-a scoping review.

BACKGROUND: Magnetic resonance elastography (MRE) of the brain allows quantitative measurement of tissue mechanics. Multiple studies are exploring possible applications in normal pressure hydrocephalus (NPH) in clinical and paraclinical contexts. This is of great interest in neurological surgery due to challenges related to diagnosis and prediction of treatment effects. In this scoping review, we present a topical overview and discuss the current literature, with particular attention to clinical implications and current challenges. METHODS: The protocol was based on the PRISMA extension for scoping reviews. After a systematic database search (PubMed, Embase, and Web of Science), the articles were screened for relevance. Thirty articles were subject to detailed screening, and key technical and clinical data items were extracted. The inclusion criteria included the use of MRE on human subjects with NPH. RESULTS: Seven articles were included in the final study. These studies had various objectives including the role of MRE in the assessment of regional elastic changes in NPH, shunt effect, and evaluation of NPH symptoms. MRE revealed patterns of mechanical changes in NPH that differed from other dementias. Regional MRE changes were associated with specific NPH signs and symptoms. Neurosurgical shunting caused partial normalization in tissue scaffold parameters. The studies were highly heterogeneous in technical aspects and design. CONCLUSION: MRE studies in NPH are still limited by few participants, variable cohorts, inconsistent methodologies, and technical challenges, but the approach shows great potential for future clinical application.

[Magnetic resonance elastography of the brain].

Magnetic resonance elastography (MRE) is a novel imaging modality allowing quantification of tissue consistency. Multiple trials have focused on the use of MRE to describe meningioma consistency prior to surgery and on improving diagnostic accuracy of normal pressure hydrocephalus and other dementias. MRE shows promising results, but still lacks direct clinical translational value. Within neurosurgery and neurosciences MRE could contribute and improve decision-making, diagnosis and treatment. Furthermore, the use of MRE will improve the basic understanding of neuroanatomy, physiology and pathology.