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Magnetic Resonance Tomography—Imaging with a Nonlinear System
Published in Alexander D. Poularikas, Stergios Stergiopoulos, Advanced Signal Processing, 2017
An interesting new application of MRI is its use as an imaging modality during minimal invasive procedures such as rf-ablation, interstitial laser therapy, or high intensity focused ultrasound. With temperature-sensitive sequences, the development of temperature and tissue damage can be checked during heating and destroying of diseased tissue. The sensitivity of MRI to flow helps the physician to stay away from vessels during an intervention. MRI is also used for image-guided surgery, e.g., resection of tumors in the brain. Special open systems have been designed for such purposes, and dedicated nonmagnetic surgery tools have already been developed.
Autofluorescence-Guided Resection of Intracranial Tumor
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Fartash Vasefi, Zhaojun Nie, David S. Kittle, Chirag G. Patil, Pramod Butte
In the United States, the incidence rate of malignant brain tumors was 7.3 per 100,000 persons per year during 2004–2008 according to the National Cancer Institute (2012). Although this rate is quite low compared to other cancers (e.g., 45 per 100,000 persons per year for colorectal cancer, according to Centers for Disease Control and Prevention, 2012), primary brain tumors, especially malignant gliomas, have a devastating effect on patients’ lives. The current 18-month survival rate of glioblastoma patients treated with surgery for biopsy only, partial resection, and complete resection ranges from 15% to 34%, making glioma one of the most aggressive and lethal tumors. Although chemotherapy and radiotherapy are used to treat glioblastoma, surgical treatment remains the most effective (Ducray et al.2010; Fazekas 1977; Robins et al. 2009). Additionally, the extent of tumor resection has been shown to be the most important factor for longer survival (Berger 1994; Byar et al. 1983; Sanai and Berger 2008). Due to the infiltrating characteristics of malignant gliomas, complete resection is difficult to achieve without removing healthy, functional, normal tissue. Several technologies, such as stereotactic image-guided surgery based on preoperative MRI scans, intraoperative ultrasound (US) (Sosna et al. 2005), and intraoperative magnetic resonance imaging (iMRI) (Elias et al. 2007), aid the surgeons to ensure the near-complete resection of the tumor. However, these techniques have their limitations. Image-guided stereotactic surgery suffers from “brain shift,” in which the accurate registration of the tumor based on preoperative MRI is lost due to movement of the brain after the craniotomy (Kubben et al. 2011). iMRI requires a large initial investment and special surgical tools. Due to space constrains, it also limits patient positioning, making it hard to reach certain areas. Intraoperative US has very low resolution. The only reliable method for intraoperative tissue diagnosis is the “frozen section,” but this time-consuming process can only be performed a limited number of times. Therefore, newer technologies are needed to aid the surgeon in achieving near-complete resection while avoiding damage to nearby eloquent areas.
Three-dimensional modelling and terahertz imaging of malignant cells with convolutional time-reversed FDTD method
Published in Electromagnetics, 2022
One of the implementations of terahertz imaging during tumor ablations is to visualize the tumors and any residuals during the surgery. The image-guided surgery is highly critical for a surgeon to ensure that all cancer cells with a rim of healthy tissue have been removed to prevent any future surgeries (Wang et al. 2018). Due to the micron-level resolution of the terahertz signals, it is a crucial technique for detecting and imaging cancer cells. This approach will cause a substantial reduction in the recovery time of the patient and the possible after-surgery treatments such as chemotherapy, radiotherapy, and immunotherapy.