Introduction:
A tumor is usually defined as a lesion that requires aggressive treatment, whereas a tumor-like lesion, like multiple sclerosis plaques, requires conservative treatment. Misinterpretation or incorrect diagnosis may cause a significant delay in the adequate treatment of malignant tumors or might result in over-treatment of a benign tumor-like lesion.
The grade of a brain tumor is assigned when the tumor cells are investigated in the laboratory. The grade helps to identify how quickly the cells are multiplying and growing. The grading is based on the alterations in the cells seen under a microscope. The grades vary from 1 to 4. A grade 1 brain tumor shows slow growth. The cells differ from the surrounding healthy cells. As the grade is increased, the cells change and start looking very different. A grade 4 brain tumor shows very fast growth.
How Are the Radiographic Features of Rare Intracranial Tumors?
Generally, anatomic imaging studies such as ultrasonography, computed tomography, or magnetic resonance imaging are used for the diagnosis of rare intracranial tumors. A tumor is usually detected due to focal density or signal alteration is observed infiltrating nearby structures with or without a contrast enhancement and might be surrounded by vasogenic edema.
Unfortunately, many intracranial lesions include multiple sclerosis plaques, resolving hematomas, abscesses, giant Virchow–Robin spaces, vascular malformations, and even metabolic conditions that might show similar radiographic features. In addition, the difficult question is the differentiation between postsurgical changes and residual tumors after brain tumor surgery.
The novel techniques of functional magnetic resonance imaging (MRI) sequences that facilitate the differentiation between tumor and tumor-like lesions include:
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Diffusion tensor imaging (DTI).
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Perfusion-weighted imaging (PWI).
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1H magnetic resonance spectroscopy (MRS).
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Susceptibility-weighted imaging (SWI).
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pH-weighted MRI.
What Are the Methods Used for the Diagnosis of Rare Intracranial Tumors?
If the healthcare provider thinks that the patient might have a brain tumor, they will require various diagnostic tests:
1. A Neurological Examination: A neurological examination examines different parts of the brain to see how it is working. This exam may include checking your vision, hearing, balance, coordination, strength, and reflexes. A neurological examination does not identify a brain tumor. It helps the healthcare provider to understand which portion of the brain might have a problem.
2. Brain MRI: Magnetic resonance imaging (MRI) utilizes strong magnets to create pictures of the inside of the body. MRI is usually used to identify brain tumors as it provides better imaging of the brain. A dye is generally injected into a vein of the arm before an MRI. The dye makes helps to create clearer pictures that make it easier to identify smaller tumors. It can help the healthcare team to identify the difference between healthy brain tissue and a brain tumor. Sometimes, the patient special may require different types of MRI to give more detailed pictures.
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In the case of functional MRI, those parts of the brain are seen that are responsible for moving, controlling speaking, and other essential activities. This helps the healthcare provider plan surgery and other treatments.
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Magnetic resonance spectroscopy is another special MRI test. This test utilizes MRI to measure levels of specific chemicals that are found in the tumor cells. Having too much or too less of the chemicals might indicate the type of brain tumor that is present.
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Magnetic resonance perfusion is another specialized type of MRI. This test helps to evaluate the amount of blood in varied portions of the brain tumor. The parts of the tumor that have a greater amount of blood might indicate the most active parts of the tumor. It helps the doctor to prepare the treatment plan accordingly.
3. Head Computed Tomography Scan: A computed tomography scan uses X-rays to take pictures. It is widely available, and results are usually can be obtained quickly. So computed tomography might be the first imaging test done in case of headaches or other symptoms with various possible causes. A computed tomography scan can detect problems in and around the brain. The results give the healthcare provider clues to decide what test to do next.
4. PET Scan of the Brain: A positron emission tomography or PET scan can help to identify certain brain tumors. In a PET scan, a radioactive tracer is used, which is injected into a vein. This tracer moves through the blood and binds to brain tumor cells. The tracer helps to mark the tumor cells in the pictures taken by the PET machine. The cells which divide and multiply rapidly take up more of the tracer.
A PET scan can be extremely helpful for identifying brain tumors that grow rapidly, like glioblastomas and certain oligodendrogliomas. Brain tumors that grow gradually might not be visible on a PET scan. Brain tumors are not cancerous and usually grow more slowly. Therefore, PET scans are less useful for benign brain tumors. A PET scan is not usually required in all patients.
5. Collecting a Sample of Tissue: A brain biopsy is a technique that involves the removal of a tumor sample tissue of brain tumor in a laboratory. A surgeon usually gets the sample while performing the surgery to remove the brain tumor.A sample can be removed with a needle If surgery is not possible. A stereotactic needle biopsy removes a sample of brain tumor tissue with the help of a needle. This procedure drills a small hole into the skull, and a thin needle is pushed through the hole. The needle helps to take a tissue sample. Prior imaging tests like CT and MRI can be used to decide the path of the needle. A needle biopsy might be required if a healthcare team is unsure whether the operation will hurt an essential brain area. Brain biopsy might lead to like bleeding in the brain and damage to the brain tissue.
Conclusion:
To plan proper treatment, estimating and differentiating between tumor and tumor-like regions is essential to establish a better prognosis. The radiologist must know about all non-neoplastic pathologies and diseases resembling tumors. High-end functional and anatomic neuroimaging tools integrating various techniques and clinical correlation are compulsory. Tumor and tumor-like lesions are lesions that look alike on ultrasound, computer tomography, or magnetic resonance imaging studies.
