Imaging Techniques in Brain Tumor

Recent years, the emerging new imaging techniques not only show the detailed and complete aspects of brain neoplasm, but also promote clinical doctors using new techniques, such as CT three-dimensional reconstruction, magnetic resonance spectroscopy (MRS), diffusion weighted imaging (DWI), diffusion tensor imaging (DTI) to research the mechanism of those diseases in the aim of better treatment. The X-ray is the fundamental technology in clinical medicine. As CT and MRI make a great progress, the X-ray takes smaller and smaller part. When the neoplasm causes skull destruction or erosion, such as osteoma or Ewing’s sarcoma of skull and pineal gland calcification, a significant X-ray can give us some useful information in diagnosis. The application of CT new technology, such as electron beam CT, dynamic CT enhancement, CT angiography and CT perfusion enhancement unfold a new boundary to neurosurgeons. Dynamic CT can not only reveal the pathophysiological change, but also make us keep an eye on local blood flow alteration. The CT angiography contains 4 methods which are threshold shaded surface display (SSD), maximum intensity projection (MIP), curved planner reformation (CPR) and volume rendering (VR). In those methods, three-dimension reconstruction takes the most important place, which gives us comprehensive observation by the complex show. On the other hand, if the blood vessels of tumor tissue need to be showed, the CT perfusion enhancement is a not bad choice, which can give clinical doctors accurate risk evaluation. The location, structure and perfusion of the neoplasm are the most important, and the answers of those significant aspects could be offered by conventional MRI. According to the distribution of the blood vessels, brain tumors can be divided into 3 types, and those provide a better differential diagnosis. Time-of-flight (TOF) and phase-contrast (PC) are the basic image formation methods. Multiple overlapping thin-slab acquisition (MOTSA) is the updated technology, which can elevate the signal overlapped vessels, display the relationships between vessels and brain. MRS can show the fineness and further, the metabolic characters of intracranial tumor. The MRS is complementary in brain neoplasm diagnosis, differential diagnosis, grading, evaluating and recurrence predicting. By determining the micrometabolite such as N-acetyl-aspartate (NAA), creatinine (Cr), choline (Cho) etc in brain, MRS could be generally applied to the brain tumor. NAA is generally accepted as a marker in central nervous system. It decreases in almost all malignant brain tumors. The Cho extremely increases in malignant brain tumors, in the meaning that conversion function of