What are the diagnostic methods for malignant glioma

Glioma is a tumor that occurs in the neuroectoderm. The incidence of glioma is relatively high among brain tumors, and it is very malignant, with a low cure rate and easy recurrence. Therefore, early diagnosis is very critical. The following introduces the diagnostic methods of malignant glioma.

1. Ultrasound examination: It can help determine the side and observe whether there is hydrocephalus. For infants, B-type ultrasound scans can be performed through the anterior fontanelle to show tumor images and other pathological changes.

2. EEG examination: On the one hand, the EEG changes of glioma are limited to the changes of brain waves in the tumor site. On the other hand, they are generally widely distributed changes in frequency and amplitude. These are affected by the size, infiltration, degree of brain edema and increased intracranial pressure of the tumor. Shallow tumors are prone to localized abnormalities, while deep tumors are less likely to have localized changes.

In more benign astrocytomas and oligodendrogliomas, localized delta waves are the main manifestations, and some epileptic waveforms such as spikes or sharp waves can be seen. Large glioblastoma multiforme can show extensive delta waves, which can sometimes only be determined on one side.

3. Cerebrospinal fluid examination: The pressure of lumbar puncture is usually increased. For some tumors, such as those located on the brain surface or in the ventricles, the amount of cerebrospinal fluid protein may increase, the number of white blood cells may also increase, and some tumor cells may be found. However, for those with significantly increased intracranial pressure, lumbar puncture has the risk of promoting brain herniation. Therefore, it is generally only performed when necessary, such as when it is necessary to distinguish it from inflammation or bleeding. For those with obvious pressure increase, the operation should be cautious and do not release too much cerebrospinal fluid. Mannitol drip is given after surgery and careful observation is required.

4. Radioisotope scanning (Y-ray brain map)

Tumors that grow quickly and have abundant blood supply have high blood-brain barrier permeability and high isotope absorption rate. For example, glioblastoma multiforme shows isotope concentration images, and there may be low-density areas in the middle due to necrosis and cysts. It needs to be distinguished from metastatic tumors based on its shape and multiplicity. More benign gliomas such as astrocytomas have lower concentrations, which are often slightly higher than the surrounding brain tissues, and the images are not clear, and some may be negative findings.

5. Radiological examination: including skull plain film, ventriculography, computed tomography (CT), PET-CT, etc.

(1) Skull X-rays can show signs of increased intracranial pressure, tumor calcification, and displacement of pineal gland calcification.

(2) Ventriculography can show the displacement of cerebral blood vessels and the condition of tumor blood vessels. These abnormal changes vary in different types of tumors in different locations and can help locate and sometimes even determine the nature of the tumor.

(3) CT scans have greater diagnostic value. The intravenous injection of contrast agent to enhance scanning has a positioning accuracy of almost 100% and a qualitative diagnosis accuracy of more than 90%. It can show the location, range, shape, brain tissue reaction, and ventricular compression and displacement of the tumor. However, it still needs to be combined with comprehensive clinical considerations to make a clear diagnosis.

(4) PET-CT (positron emission tomography) can distinguish between benign and malignant tumors, produce images similar to CT, and observe the growth and metabolism of tumors.

6. Magnetic resonance imaging: It is more accurate in diagnosing brain tumors than CT, and the images are clearer. It can detect tiny tumors that CT cannot show.