Project Title: Identification
of the stage and the age
of intracerebral hemorrhage
1.INTRODUCTION
Pathology is the study of the processes underlying disease and other forms of illness, damage, abnormality, or dysfunction, which is specifically the study of the structural and functional changes in cells, tissues and organs that underlie disease. Therefore, the primary goal of pathology is the study of the four main aspects of a disease: etiology, pathogenesis, morphologic changes and clinical significance. One of the major areas of research of pathology is neuropathology which is the study of disease of the nervous system and brain.
Major pathologies of brain can be classified as tumors, hemorrhage, and cyst. A brain tumor is any intracranial mass created by an abnormal and uncontrolled growth of cells either normally found in the brain itself, in the cranial nerves, in the brain envelopes or spread from cancers primarily located in other organs. Brain tumors arising exclusively from cells normally present in the brain itself are called primary brain tumors, and those that originate from malignant tumors (cancers) located primarily in other organs are called secondary or metastaic brain tumors.
A cyst is a closed sac having a distinct membrane and developing abnormally in a cavity or structure of the body. Cysts sometimes arise spontaneously with no apparent cause. They may often be dangerous as they may have negative effects on the nearby tissue. They may contain air, fluids, semi-solid material or organisms.
Common properties of brain pathologies discussed above are edema, hemorrhage, ischemia, and necrosis. Based on the development stage of the pathology, they share one or more of these properties, where they all have individual characteristics which result in different views in images obtained from medical imaging modalities such as CT and MR.
Brain edema is the accumulation of excessive fluid in the substance of the brain. The brain is especially susceptible to injury from edema, because it is located within a confined space and cannot expand. Brain edema or so called cerebral brain edema, is one of the most important factors leading to morbidity and mortality associated with brain tumors and hemorrhage.
Ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue.
Ischemia can also be described as an inadequate flow of blood to a part of the body, caused by constriction or blockage of the blood vessels supplying it. Ischemia in brain tissue causes a process in which harmful chemicals damage and may ultimately kill brain tissue.
Necrosis is the name given to unprogrammed death of cells/living tissue. It is the death and destruction of cells and tissues, caused by action of enzymes. Necrosis accompanies numerous pathologic processes, such as hemorrhage, tumors, and ischemia.
Intracerebral hemorrhage (ICH) is defined as bleeding into the brain parenchyma that may extend into the ventricles and in rare cases into the subarachnoid space. It is the most common form of hemorrhage (Kalita et.al, 2005).
Intracerebral hemorrhage occurs when a diseased blood vessel within the brain bursts, allowing blood to leak inside the brain. The sudden increase in pressure within the brain can cause damage to the brain cells surrounding the blood. If the amount of blood increases rapidly, the sudden buildup in pressure can lead to unconsciousness or death. Intracerebral hemorrhage usually occurs in selected parts of the brain, including the basal ganglia, cerebellum, brainstem, or cortex.
Intracranial hemorrhages cause injury to the brain in two ways: direct local injury at the site of the hemorrhage and global injury from increases in intracranial pressure (ICP). The leakage of blood causes local damage to the brain parenchyma at the site of hemorrhage. The blood also can dissect along white matter planes into deeper regions of the brain, extending the focal injury. Because the cranial vault is a closed, rigid space with a fixed volume, alterations in its contents can lead to significant changes in ICP (Jauch and Elias, 1993).
After intracranial hemorrhage, fluid in the extracellular space surrounding the hematoma increases, producing edema. The cause and clinical significance of this perihematomal edema is the focus of ongoing research. This perihematomal edema adds further mass to the cranial vault, aggravating the rise in ICP.
As ICP increases, brain tissue shifts, and herniation can occur. This condition can lead to remote areas of the brain becoming injured. Shifts can cause vascular occlusion and resulting infarction by compressing vascular structures against rigid intracranial structures. Brain parenchyma and cranial nerves also can be compressed. The nerves are compressed by brain shifts, causing a dilated and unresponsive pupil. When the shifts become severe, herniation can develop (Matta et.al, 2000). Herniation and impending brain death are clinically heralded by coma, posturing, bilateral pupillary dilation, and autonomic liability. Most medical and surgical treatments are aimed at preventing these secondary effects.
2. MATERIAL AND METHOD
The different paramagnetic forms of hemoglobin and their intra-/extracellular environment lead to a characteristic MR appearance of evolving intracerebral hemorrhage. "Hyperacute" hemorrhage contains oxyhemoglobin, "acute" hemorrhage contains deoxyhemoglobin, "subacute" hemorrhage contains methemoglobin, and "chronic" hemorrhage contains hemichromes (hemosiderin and ferritin).
Subacute hemorrhage can be further divided into "early" and "late" forms depending on the time of red cell lysis. Early subacute hemorrhage (intracellular methemoglobin) appears at approximately three days and lasts for about a week. The late subacute phase (extracellular or "free" methemoglobin) appears at approximately one week post ictus. The chronic phase is defined on MR images by the presence of a hemosiderin rim surrounding the free methemoglobin and hemichromes. Both T1- and T2-weighted images are required for adequate MR characterization of evolving hemorrhage.
The development of intracranial hemorrhage in daily routine MR imaging is well described and documented in the literature. This available information will be the starting point for our research. Every stage of the hemorrhage is composed of different biological materials resulting in different intensities and/or combination of intensities in the final image. Methods for extracting information or features from 2D images are known as image processing, which has a wide range of applications in the literature. Image processing techniques will be used in the analysis of intracranial hemorrhage on MR images to estimate its stage and age, and identify brain pathologies.
All the work will be conducted in a software environment. Our dedicated software “Volume Processor” will be used for this purpose which has several two and three dimensional data analysis features available, and where all of them are designed to implement specific image processing techniques. If necessary, additional algorithms will also be developed and plugged-in to the software.
A suitable method which has the potential of solving the stage estimation problem may be the histogram analysis where it provides a convenient mechanism for establishing, and utilizing, the spatial correlation of intensities within images. Brightness and contrast analysis methods will also be considered.
3. RESULT
Estimation of the stage and the age hemorrhage is important since it shows the exact state of the brain injury and the state of the inflammation, and therefore affects the rest of the therapy. During literature research, it is found out that this process is carried out only by observation of MR images, which requires high level of expertise in this field. Considering the complex parameters that affect the appearance of intracerebral hematoma on MRI, it is obvious that, “estimation by observation” method is sensitive to experience and may be subjected to misunderstanding of the actual stage of the hemorrhage. The objective of this work is to develop computer based methods which estimates the stage and the age of hemorrhage accurately, and if possible, identify other forms of brain pathologies, and therefore reduces the risks involved in these processes.
Intracerebral hemorrhage has a high mortality ratio which varies between 20% and 56%. Every year millions of people are dying because of ICH. Survivors of ICH have to face a number of permanent effects. One of main concerns in the treatment of intracerebral hemorrhage is the brain injury. Brain injury can occur from either mechanical or toxic effects. The information of the stage and age of hemorrhage also provides information about the mechanical and toxic injury state in the brain and therefore plays an important role in the rest of the therapy. Estimation of the stage of hemorrhage via computer based methods;
• Helps non-experts to understand the actual state of the hemorrhage,
• Provides an ability to understand the beginning time of bleeding of unconscious patients,
• Is important either from medico-legal or surgical intervention point of view,
• Identifies the actual state of a brain injury,
• Simplifies the estimation process,
• Reduces human based mistakes.
Treatment strategies of brain tumors are based on the type of tumor, the stage of the cancer and the needs of the patient. There are more than 120 different types of brain tumors. Many tumors have also different subtypes. The same tumors sometimes have different names and even pathologists are not always consistent in what they call them. Generally, based on the treatment strategies, tumors can be classified into five major types as: gliomas (primary brain tumors), metastatic brain tumors, pituitary tumors, meningiomas, and pediatric brain tumors. Currently, identification of these tumor types is based on surgery such as biopsy methods. Identification of the type of brain tumors via computer based methods;
• Reduces or removes the need to open, stereotactic, and/or needle biopsy
• Improves the diagnosis methods by accelerating the process
• Reduces risks involved in treatment process by reducing the surgery needs
• Improves stereotactic operations by providing 3D spatial information about the tumors
• Provides information about the location, size and number of tumors in addition to borders or edges of the tumors which is of vital importance for surgery decisions and planning
• Reduces financial requirements for the overall treatment process
• Helps non-experts to understand the actual type of the tumor.