**4.3. Radiological methods**

#### *4.3.1. CT scan*

Use of CT scan has gained preference over other methods during last few decades for diagnosis [13, 14]. CT scan or X‐ray CT involves two dimensional X‐ray images of the brain from several possible angles and computer‐based analysis for any deformities. Sometimes, dyes are also used to differentially highlight the different parts of brain [15]. This technique clearly visualizes any type of blood hemorrhage, clot, swellings, infections, or inflammations in the brain or the meninges. The dark areas signify for edema, whereas bright areas signify calcification or hemorrhage of the brain tissue. Although the high resolution of CT scan proved it to be better diagnostics method over others conventional methods but is associated with several side effects like damaging tissue and cancer. Therefore, is less preferred in the case of infants or children.

#### *4.3.2. MRI‐based detection*

Since 1970, after discovery, MRI is used as one of most versatile and prominent diagnostic tool in biomedical research. MRI or NMRI uses magnetic fields, radio waves, and field gradients to image the anatomy or physiological structure of brain [16]. A clear image obtained there of reveals any infection or inflammation in the brain or meninges. Since, this technique does not use any ionizing radiations and has a higher sensitivity, therefore, preferred over CT scan. This method is sometimes time‐consuming, expensive, and cumbersome [17].

#### *4.3.3. Brain biopsy*

pathogens or their by‐products, presence of lactic acid, lactate dehydrogenase, or C‐reactive proteins or increase in the white blood cells (WBCs) count of CSF can be detected by various methods [9, 10]. CSF‐based detection is one of the traditional methods used for the diagnosis of several disorders associated with the central nervous system. Although the method is less

This is a noninvasive electrophysiological technique which analyze the electrical signals or ionic current within the neurons of the brain. Any abnormalities or functional changes in the brain cause change in neural oscillation or brain waves over a period of time which can be detected [11]. The pattern of the waves in an electroencephalogram signifies the specific type of seizure or viral infection [12]. Despite its low resolution, it is still used as one of the pioneer diagnostic tool. This method consumes several hours for complete detection of the pathogen.

HME may cause partial or complete impairment of the brain and the sensory system in the patient. Therefore, physician carries out neurological examinations to confirm the infection. Neurological examination is carried out through series of tests to detect neurological disorders, mental status, strengths of sensation, and behavioral changes. Simple instruments like forks, reflex hammer, or small pins are used by the physicians to detect the strength of the neurological response. But this test is nonspecific and misleading because it cannot discrimi-

Use of CT scan has gained preference over other methods during last few decades for diagnosis [13, 14]. CT scan or X‐ray CT involves two dimensional X‐ray images of the brain from several possible angles and computer‐based analysis for any deformities. Sometimes, dyes are also used to differentially highlight the different parts of brain [15]. This technique clearly visualizes any type of blood hemorrhage, clot, swellings, infections, or inflammations in the brain or the meninges. The dark areas signify for edema, whereas bright areas signify calcification or hemorrhage of the brain tissue. Although the high resolution of CT scan proved it to be better diagnostics method over others conventional methods but is associated with several side effects like damaging tissue and cancer. Therefore, is less preferred in the case of infants or children.

Since 1970, after discovery, MRI is used as one of most versatile and prominent diagnostic tool in biomedical research. MRI or NMRI uses magnetic fields, radio waves, and field gradients

time consuming, it is low sensitivity and nonspecific.

52 Meningoencephalitis - Disease Which Requires Optimal Approach in Emergency Manner

nate between HME and meningocephalitis due to other causes.

**4.2. Non‐laboratory tests**

*4.2.1. Electroencephalography*

*4.2.2. Neurological examinations*

**4.3. Radiological methods**

*4.3.2. MRI‐based detection*

*4.3.1. CT scan*

This technique involves digging a hole at a point in the skull identified through CT scan or MRI, collection of small tissue using sterilized needle, and then observation under microscope [18]. The status or condition of the brain and its surrounding tissue can be analyzed through this method. HME is detected depending upon the swelling or damage of the tissue. This method although is highly sensitive but painful and associated with several complications. Therefore, this method was slowly replaced by other methods.
