Quantitative Susceptibility Mapping in Cerebral Cavernous Malformations: Phantom vs Human lesions
Poster No:
96
Submission Type:
Abstract Submission
Authors:
Ogechukwu Ngwu-Hyacinth1, Williams Willoughby1, Mark Bolding1
Institutions:
1THE UNIVERSITY OF ALABAMA AT BIRMINGHAM, Birmingham, AL
First Author:
Co-Author(s):
Introduction:
Cerebral cavernous malformation (CCM) is a vascular anomaly affecting over 0.5% of the population, with a heightened risk of stroke and epilepsy due to recurring lesional hemorrhages. Currently, surgery is the only definitive treatment[1], but this poses a significant risk of morbidity and mortality. We propose magnetic resonance image-guided focused ultrasound (MRgFUS) treatment of CCM lesions, a technique combining magnetic resonance imaging (MRI) and focused ultrasound (fUS) for visualizing, targeting, and monitoring lesions.
Studies have shown that the thermal energy released at the focus of the ultrasound can induce ablation of vascular lesions. Furthermore, MRI, particularly utilizing gradient echo T2 star-weighted and susceptibility-weighted imaging, is recommended for CCM detection[1]. Additionally, MRI has been shown to produce real-time temperature maps and estimates of tissue coagulation during the ablation process [2]. However, susceptibility artifacts from hemorrhagic residues in vascular lesions hinder accurate temperature monitoring during MRgFUS treatment[3]. The study aims to address this knowledge gap by using quantitative susceptibility mapping (QSM), an MRI technique, to estimate iron content in CCM phantoms.
Objectives: - To compare the susceptibility of CCM phantoms with the susceptibility of CCM lesions in humans.
Studies have shown that the thermal energy released at the focus of the ultrasound can induce ablation of vascular lesions. Furthermore, MRI, particularly utilizing gradient echo T2 star-weighted and susceptibility-weighted imaging, is recommended for CCM detection[1]. Additionally, MRI has been shown to produce real-time temperature maps and estimates of tissue coagulation during the ablation process [2]. However, susceptibility artifacts from hemorrhagic residues in vascular lesions hinder accurate temperature monitoring during MRgFUS treatment[3]. The study aims to address this knowledge gap by using quantitative susceptibility mapping (QSM), an MRI technique, to estimate iron content in CCM phantoms.
Objectives: - To compare the susceptibility of CCM phantoms with the susceptibility of CCM lesions in humans.
Methods:
To make the CCM phantom, jelly beads were made from a mixture of red-colored liquid containing 2g of Iron (III) citrate (0.1g Fe2+) and sodium alginate spherified in a Calcium lactate solution and frozen to achieve a solid consistency. To mimic CCM lesions, three gelatin brain molds were embedded with the frozen jelly beads and the mold was allowed to form at room temperature. MRI images were acquired at 3.0T using TE = 10ms, TR = 100 ms, 30cm field of view and 128*128 matrix. MRI data were analyzed using FSL (www.fmrib.ox.ac.uk/fsl). QSM maps were reconstructed from data acquired with a 3-dimensional T2*-weighted gradient echo sequence. To validate our QSM estimates, the mean susceptibility values of the CCM phantoms were correlated with the QSM-derived iron measurements in human patients[4].
Results:
The iron-embedded jelly beads appeared hyperintense on the QSM maps compared to the nearby gelatin mold. The susceptibility of iron in these phantoms, as demonstrated by QSM, averages about 2ppm, similar to the iron content of human CCM lesions, as shown in this paper [4].
Conclusions:
This preliminary experiment developed a phantom with similar magnetic, spin relaxation and susceptibility properties as a human CCM to enable testing various MRI pulse sequences and monitoring temperature feedback during fUS treatment on phantom models. While acknowledging iron as the assumed predominant susceptibility source in the phantom, the study concludes that high-field MRI techniques, particularly QSM, offer new avenues for CCM lesion monitoring. Future investigations will explore correlations between susceptibility and physical properties of CCM phantoms, informing the transition to in-vivo animal models and, eventually, clinical trials.
Brain Stimulation:
Sonic/Ultrasound 1
Novel Imaging Acquisition Methods:
BOLD fMRI 2
Keywords:
FUNCTIONAL MRI
ULTRASOUND
1|2Indicates the priority used for review
Provide references using author date format
2. Nosova, K. (2023). History of Ablation Therapies in Neurosurgery. Neurosurgery Clinics of North America, 34(2), 193–198.
3. Tan, H. (2016). Quantitative Susceptibility Mapping in Cerebral Cavernous Malformations: Clinical Correlations. AJNR. American journal of neuroradiology, 37(7), 1209–1215.
4. Tan, H. (2014). Evaluation of iron content in human cerebral cavernous malformation using quantitative susceptibility mapping. Investigative radiology, 49(7), 498–504.