MRI Analysis Method

Next, I will introduce the Part 2 topic is the Magnetic Resonance Image Analysis Method and Method for Evaluating the Risks of Radiotherapy Cerebral AVM (arterio-venous malformation) is a congenital cerebral vascular disease with an incidence rate. An AVM comprises an abnormal nidus of blood vessels that shunt blood directly from an artery to a vein and thereby bypass an intervening capillary bed. it can take 2–3 years after GKRS Radiosurgery before the AVM is obliterated, and adverse radiation effects (ARE) during the latency period can lead to brain edema. There are many complication after GKRS Radiosurgery such as the Cerebral infracts and others. This is the Strategy of Radiosurgery for AVMs in Taipei hospital.

Including the Imaging procedures, AVM nidus delineation, dose planning, dose prescription, staged radiosurgery and the follow-up. This figure shows the Histographic Characterization of Cerebral AVM. The intensity histogram of the T2w image was obtained within the radiation exposure region, with the nidus (dark blue), brain tissue (green), and CSF (red) demarcated manually. (A) The red curve indicates the region exposed to radiation; (B) The blue, green, and red colors indicates respectively indicate the nidus, brain tissue, and CSF delineated via manual segmentation. The figure (C) Intensity histogram of nidus, brain tissue, and CSF obtained using manual segmentation within the region exposed to radiation. Manual clustering was performed by an experienced neurosurgeon according to the radiation exposure region and T2w intensity.

Preprocessing was performed to obtain the boundary of the prescription isodose region within the parenchymal brain in T2w images. The areas of the nidus, brain tissue, and CSF within the boundary were identified via manual demarcation. In fuzzy c-means (FCM) clustering, each data point may belong to more than one. This image analysis technique is well established in tumor detection. Clustering and cluster analysis involves assigning data points to clusters to ensure that items in a given cluster are as similar as possible and that items belonging to different clusters are as dissimilar as possible. Clusters are identified using similarity measures, such as distance, connectivity, and intensity. The choice about which measures to use is based on available data or the intended application.

Our objective in this study was to use the FCM technique to classify the prescription isodose radiation exposure range in T2 weighted (T2W) images for GKRS plans with the aim of calculating precise percentages and volumes of the various forms of tissue.