Tag: susceptibility-weighted imaging

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Radiological and anatomical evaluation of the internal venous system in the context of access to the third ventricle ‑ proposal of a new classification

Acta Neurochirurgica (2025) 167:23

The internal venous system of the brain is a crucial anatomical landmark during accesses to the third ventricle through the foramen of Monro. Many classifications based on radiological assessment of the system have been developed, but they tend to be descriptive and do not highlight favorable anatomical variants. The aim of our study was to create a system based on morphometric measurements to facilitate preoperative decision-making regarding access to third ventricle tumors.

Methods We conducted an analysis of 119 MRI scans with SWI sequence using BrainLab software to create a model of the ventricular system, which allowed us to perform radiological measurements. We then validated these findings anatomically using 32 human brain specimens. The analyzed structures included the foramen of Monro (FM), the anterior septal vein (ASV), the thalamostriate vein (TSV), the venous angle (VA), the internal cerebral vein (ICV), and the distance between the FM and VA.

Results Based on the radiological analysis, we identified 9 internal venous systems, accounting for variations in each analyzed structure. The statistical analysis revealed no differences in the frequency of subtypes between radiological and anatomical studies (p = 0.097), nor in the occurrence of false venous angles (p = 0.520). We identified venous configurations that, in our assessment, are unfavorable in the context of accessing the third ventricle.

Conclusion The resulting classification accounts for significant clinical anatomical variations and, for the first time, provides specific morphometric values for each anatomical subtype. Consequently, it serves as a reproducible reference framework for preoperative planning of access to the third ventricle.

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Fractal Analysis for the Differentiation of Brain Tumors Using 3-Tesla Magnetic Resonance Susceptibility-Weighted Imaging

Neurosurgery 79:839–846, 2016

Susceptibility-weighted imaging (SWI) of brain tumors provides information about neoplastic vasculature and intratumoral micro- and macrobleedings. Low- and high-grade gliomas can be distinguished by SWI due to their different vascular characteristics. Fractal analysis allows for quantification of these radiological differences by a computer-based morphological assessment of SWI patterns.

OBJECTIVE: To show the feasibility of SWI analysis on 3-T magnetic resonance imaging to distinguish different kinds of brain tumors.

METHODS: Seventy-eight patients affected by brain tumors of different histopathology (low- and high-grade gliomas, metastases, meningiomas, lymphomas) were included. All patients underwent preoperative 3-T magnetic resonance imaging including SWI, on which the lesions were contoured. The images underwent automated computation, extracting 2 quantitative parameters: the volume fraction of SWI signals within the tumors (signal ratio) and the morphological self-similar features (fractal dimension [FD]). The results were then correlated with each histopathological type of tumor.

RESULTS: Signal ratio and FD were able to differentiate low-grade gliomas from grade III and IV gliomas, metastases, and meningiomas (P , .05). FD was statistically different between lymphomas and high-grade gliomas (P , .05). A receiver-operating characteristic analysis showed that the optimal cutoff value for differentiating low- from highgrade gliomas was 1.75 for FD (sensitivity, 81%; specificity, 89%) and 0.03 for signal ratio (sensitivity, 80%; specificity, 86%).

CONCLUSION: FD of SWI on 3-T magnetic resonance imaging is a novel image biomarker for glioma grading and brain tumor characterization. Computational models offer promising results that may improve diagnosis and open perspectives in the radiological assessment of brain tumors.

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Electrophysiological validation of STN-SNr boundary depicted by susceptibility-weighted MRI

Electrophysiological validation of STN-SNr boundary depicted by susceptibility-weighted MRI

Acta Neurochir (2015) 157:2129–2134

Direct targeting of subthalamic nucleus (STN) without secondary electrophysiological verification during deep brain stimulation (DBS) is replacing atlas-based indirect targeting techniques. Recent groups have reported increased contrast and better delineation of STN and substantia nigra (SNr) in susceptibility-weighted imaging protocols (SWI). We aim to validate the STN-SNr boundary seen in MRISWI by correlating with intraoperative microelectrode recordings (MER) as a part of developing a multi-contrast DBSMRI planning protocol.

Methods Prospective service evaluation involving electrophysiological verification by correlation of MER trajectory and STN-SNr boundary seen in SWI in seven consecutive patients undergoing DBS surgery were analyzed. The angle of inclination of the STN-SNr boundary and DBS trajectory in the coronal plane were calculated. Considering 4-mm dispersion of a coronal 3 MER array, we predicted, measured, and correlated the depths at which each electrode engaged the boundary.

Results All central microelectrodes identified the STN-SNr boundary within 1 mm of the predicted depth with 100 % accuracy. Ninety percent of the lateral MER identified the STN-SNr boundary as predicted from SWI and angle of the encounter of the MER front.

Conclusions The study demonstrates that STN morphology can be depicted using SWI MRI and coincides reliably with the electrophysiological MER boundary. Thus, this imaging modality can be used to refine STN direct targeting protocols in DBS surgery for PD.

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Isolated cortical vein thrombosis

Isolated cortical vein thrombosis

J Neurosurg 123:427–433, 2015

Isolated cortical vein thrombosis (ICVT) accounts for less than 1% of all cerebral infarctions. ICVT may cause irreversible parenchymal damage, rendering early and accurate diagnosis critical. This case series and literature review presents the clinical and radiological findings in 7 patients with ICVT, and highlights risk factors and imaging modalities that may be most beneficial in rendering an accurate and timely diagnosis.

Methods Patients with CT and MRI findings consistent with ICVT examined between January 2011 and June 2014 were included in this retrospective review.

Results Seven patients (5 females, 2 males), ranging in age from 11 months to 34 years, met the inclusion criteria. The most common clinical presentations were headaches (n = 4) and seizures (n = 3). The most common comorbidities noted in these patients were hypercoagulable states (n = 4) and intracranial hypotension (n = 3). Five patients had intraparenchymal involvement. CT suggested the correct diagnosis in 4 patients, and MRI confirmed the diagnosis in all 7 patients. All patients who received anticoagulation therapy (n = 5) experienced complete resolution of their symptoms.

Conclusions The majority of these patients were adult females, consistent with published data. Seizures and headaches were the most common presenting symptoms. Hypercoagulable state and intracranial hypotension, both known risk factors for thrombosis, were the most commonly noted ICVT risk factors. Intraparenchymal involvement was prevalent in nearly all ICVT cases and presented as vasogenic edema, early intraparenchymal hemorrhage, or hemorrhagic venous infarction. Susceptibility-weighted imaging was the most sensitive imaging technique in diagnosing ICVT.

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