Differentiating brain radionecrosis from tumour recurrence: a role for contrast-enhanced ultrasound?

Implication of tumor morphology and MRI characteristics on the accuracy of automated versus human segmentation of GBM areas

An assessment scheme is proposed to evaluate GBM gross tumor core and T2-FLAIR hyper-intensity segmentations on preoperative multicentric MR images as a function of tumor morphology and MRI characteristics. 74 gross tumor core and T2-FLAIR hyper-intensity BraTS-Toolkit and DeepBraTumIA automatic segmentations, and 42 gross tumor core neurosurgeon manual segmentations were accordingly evaluated. Brats-Toolkit and DeepBraTumIA generally provide accurate segmentations, particularly for the most common round-shaped or well-demarked tumors, where: (1) gross tumor segmentation correctly includes necrosis and contrast enhanced tumor in 100% and 97.06% of cases (vs. 73.68% for manual segmentation) and wrongly includes healthy or non-tumor related tissues in 2.94% and 20.59% of cases (vs. 10.53% for manual segmentations); (2) T2-FLAIR hyper-intensity segmentations completely includes edema in 88.24% of cases for both software. MR image quality has little impact on the segmentation performance on these tumors. Conversely, on less common tumors with more complex tissue distribution and infiltrative behavior, manual segmentation works better than BraTS-Toolkit and DeepBraTumIA, and image quality has a larger impact on automatic segmentation performance. BraTS-Toolkit and DeepBraTumIA gross tumor segmentation properly includes necrosis and contrast enhanced areas in 50% and 37.50% of cases (vs. 66.67% for manual segmentation), all corresponding to higher image quality; T2-FLAIR hyper-intensity segmentation wrongly includes necrosis and contrast enhanced areas in 37.50% and 50% of cases.

Intraoperative ultrasound in brain tumor surgery: A review and implementation guide

Accurate and reliable intraoperative neuronavigation is crucial for achieving maximal safe resection of brain tumors. Intraoperative MRI (iMRI) has received significant attention as the next step in improving navigation. However, the immense cost and logistical challenge of iMRI precludes implementation in most centers worldwide. In comparison, intraoperative ultrasound (ioUS) is an affordable tool, easily incorporated into existing theatre infrastructure, and operative workflow. Historically, ultrasound has been perceived as difficult to learn and standardize, with poor, artifact-prone image quality. However, ioUS has dramatically evolved over the last decade, with vast improvements in image quality and well-integrated navigation tools. Advanced techniques, such as contrast-enhanced ultrasound (CEUS), have also matured and moved from the research field into actual clinical use. In this review, we provide a comprehensive and pragmatic guide to ioUS. A suggested protocol to facilitate learning ioUS and improve standardization is provided, and an outline of common artifacts and methods to minimize them given. The review also includes an update of advanced techniques and how they can be incorporated into clinical practice.

Cottonoid-guided intraoperative ultrasonography in neurosurgery: a proof-of-concept single surgeon case series

Ultrasonography was introduced into neurosurgery in the 1950s, but its successful utilization as an intraoperative tool dates from the early 1980s. However, it was not used widely because of limited technology, a lack of specific training, and, most importantly, the concurrent evolution of computerized tomography and magnetic resonance imaging. The intraoperative use of cottonoid patties as acoustical markers was first described in 1984, but the practice did not gain acceptance, and no articles have been published since. Herein, we reconsider the echogenic properties of the surgical cottonoid patty and demonstrate its usefulness with intraoperative ultrasonography (ioUS) in neurosurgical practice as a truly real-time neuronavigation tool. We also discuss its advantages and compare it with other intraoperative image guidance tools. The echogenic properties of the handmade cottonoid patties in various sizes used with ioUS are described. Details of our cottonoid-guided ioUS technique and its advantages with illustrated cases are also described. As an echogenic marker, cottonoid patties can be easily recognized with ioUS. Their usage with ultrasonography provides truly real-time anatomical orientation throughout the surgery, allowing easy access to intraparenchymal pathologies, and precise and safer resection. Cottonoid-guided ioUS helps not only to localize intraparenchymal pathologies but also to delineate the exact surgical trajectory for each type of lesion. Furthermore, it is not affected by brain shift and distortion. Thus, it is a truly real-time, dynamic, cost-effective, and easy-to-use image guidance tool. This technique can be used safely for every intraparenchymal pathology and increases the accuracy and safety of the surgeries.

How to Perform Intra-Operative Contrast-Enhanced Ultrasound of the Brain-A WFUMB Position Paper

Intra-operative ultrasound has become a relevant imaging modality in neurosurgical procedures. While B-mode, with its intrinsic limitations, is still considered the primary ultrasound modality, intra-operative contrast-enhanced ultrasound (ioCEUS) has more recently emerged as a powerful tool in neurosurgery. Though still not used on a large scale, ioCEUS has proven its utility in defining tumor boundaries, identifying lesion vascular supply and mapping neurovascular architecture. Here we propose a step-by-step procedure for performing ioCEUS analysis of the brain, highlighting its neurosurgical applications. Moreover, we provide practical advice on the use of ultrasound contrast agents and review technical ultrasound parameters influencing ioCEUS imaging.

Radiation-Induced Brain Aneurysms: Institutional Experience and State of the Art in the Contemporary Literature

BACKGROUND

Brain aneurysms (BAs) are the most common intracranial vascular condition, with an overall incidence of 1%-2%. Among the common causes of their initial formation and growth, the role of radiation therapy (RT) has been reported in some studies. The aim of the present study is to report the most relevant features of BA related to a previous cranial RT.

METHODS

Data deriving from 1 patient treated for RT-induced BA in our institution were added to reports of another 66 BAs retrieved from the literature. The following parameters were evaluated: age, sex, location, primary lesion, clinical presentation, dosage/amount of radiation delivered, type of treatment for the BA, dimension, morphology, chemotherapy, comorbidities, risk factors, and number of BAs.

RESULTS

The most commonly involved vessel was the internal carotid artery (34%). In general, the anterior circulation showed higher vulnerability compared with the posterior circulation and middle cerebral artery (56.7%). The average latency between RT and the first imaging showing the BA was 9.01 ± 6.85 years. Vessels coursing in the posterior cranial fossa showed a significant univariate association with lower X-ray dosages (P = 0.014) compared with the other locations. No statistically significant correlation between the continuous variables age, latency of BA appearance, RT delivered dose, and dimension of the BA was shown.

CONCLUSIONS

The apparent higher fragility of the vascular structures of the posterior cranial fossa was statistically outlined, and the X-ray dosage, the primary condition target of the RT, the age of the patients, and no statistically significant correlation were outlined. Biological factors could play a significant role.