List of Contents
MRI of the Head/Brain
In the context of whole-body magnetic resonance imaging, the tissues and structures of the head and brain are presented and analyzed. In the following, we focus on diseases of the head/brain which MRI can image in any plane with excellent soft tissue resolution.
With the help of the MRIs, fresh and old strokes or circulatory disorders can be safely detected. The diffusion MRI can play an important role as a modern additional method.
This modern additional method can be used to prove tissue changes in brain areas that are not adequately supplied with oxygen, as is common in a stroke. In this process, very early stages of stroke can be detected and thus started early with the therapy in order to prevent serious damage to the brain.
Changes of the brain tissue are detected and the MRI images are transferred to the treating cardiologist or neurologist for further diagnosis and treatment.
In addition to the depiction of ischemic brain areas and the vascular status, bleeding into the brain tissue can also be discovered with the help of MRI scans. Due to the high sensitivity of this technology it is even possible to differentiate between acute, older and chronic bleeding.
Degenerative Mark Bearing Changes
A degenerative mark bearing change is a pathological change in the nerve fibres in the central brain area of the cerebrum and the cerebellum.
Special risk groups, such as patients with hypertension, smokers or diabetics may be affected by these morbid nerve changes. These can be perfectly represented and localized with MRI imaging.
Magnetic resonance imaging is also suitable for depicting the location and expansion of benign or malignant brain tumors. Among the first group are the meningiomas and pituitary adenomas.
Meningiomas are caused by pathological cell changes in the so-called arachnoid mater, which lies below the dura mater which is part of a three-layered system of membranes to protect the brain. There are fast and slow growing meningiomas that can also grow into the meninges. These examinations require the application of contrast agents.
Pituitary adenomas are benign tumors of the gland, a central hormonal control point. Active adenomas release hormones, but in an uncontrolled way. As a result, typical symptoms of the disease may occur. Patients complain, for example, about tension, hot flashes or pain in the joints. Already small precursors of this tumor can be detected in the MRI, therefore, in this case, an imaging diagnostic with the MRI is very helpful to define the cause of the discomfort or to identify early tumorous stages before signs of disease arise.
In addition to the clinical examination, MRI is the method of choice to detect malignant brain tumors, for example gliomas. Gliomas are morbid tumors of the soft support tissue of the nerve cells. The aggressive, malignant forms, e.g. the glioblastoma, infiltrate the brain tissue with potentially fatal consequences.
In addition to brain tumors, metastases from other tumors developing in other parts of the body can also be discovered. The extent of metastasis is of particular importance for the further treatment of a tumorous disease. The MRI images contribute to a deliberately planned diagnosis or planning of further therapies.
Due to MRI oncologists are able to analyze the operability of benigne or malignant tumors. On the basis of the whole-body MRIs, small tumors or metastases are already depictable, enabling early and promising therapies.
Dementia Diagnosis/Brain Atrophy
Various forms of dementia can be represented and determined by means of the MRI images using typical markers. We can diagnose the loss of the grey or white brain substance or also the general decline in brain tissue (brain atrophy).
Additionally, we can detect the smallest circulatory disorders of the vessels (micro- or macroangiopathy) caused by scar formation in the cerebrum.
Please note that preventive MRI imaging makes it possible to treat patients at an early stage of disease!
Inflammatory processes can also affect brain tissue. For example, multiple sclerosis is a potentially progressive, autoimmune neurologic disorder of the central nervous system, resulting from an autoimmune attack on central nervous system white matter. The nerve fibres involved are degraded by the body’s own immune system.
The MRI can clearly differentiate between the inflammation processes (lesions or plaque) and the healthy tissue. Acute or active stages of the disease can be clearly distinguished from older ones with the help of MRI contrast agents. That’s how the development of the disease can be traced for years.
Circulatory Disorders of the Brain Fluid
The healthy brain tissue contains a certain level of brain water, the quantity of which is kept in equilibrium by a well-coordinated system of production and degradation/ discharge.
The so-called hydrocephalus (water head) shows an expansion of the inner and outer liquors due to high amounts of brain water. The status of the hydrocephalus can be easily determined with the MRI.
A misdevelopment of the cerebellum – the Arnold-Chiari-Malformation – is also detectable. The diagnostic means of choice is also the MRI.
Constitutional Changes/ Anomalies/ Brain Tissue Scars
In the MRI examination of the brain, cystic changes in the tissue structures can also be noticed: This includes, for example, the arachnoidal and the pineal cysts. The former are formed in the area of the so-called arachnoidal mater, the latter in the pineal gland. They are fluid-filled, benign spatial demands that do not need to be treated if they do not cause any symptoms. They are usually discovered by the MRI as a random finding.
Vascular anomalies (malformations) of the brain tissue – “developmental venous anomaly” can also be visualised. These are veins whose shape and volume do not correspond to the norm, but usually do not cause any symptoms.
In addition, angiomas can be discovered: these are vascular malformations of the arteries and veins of the brain, which lead to symptoms like bleeding, epileptic seizures or neurological disorders. These malformations can already be detected by the whole-body MRI before they become symptomatic.
The MRI images also provide us with information about possible bulges or outdents of the brain vessels (aneurysms). This examination is performed in addition of contrast agents. Aneurysms can be harmless, but the larger they are, the greater the risk of rupture (a tearing of the wall), which causes a dangerous cerebral hemorrhage. In rare cases, when they have reached a significant size they can affect neighbouring structures.
During the MRIs, we can analyze the status of the brain vessels and recommend further diagnosis or therapy.
Due to the contrast agent the graduation of stenoses or buckling is also often noted on MRI imaging. In these areas the blood flow is accelerated, which can be seen indirectly in the MRI.
Deposits on the vascular walls (calcium or cholesterol deposits – arteriosclerosis), which can lead to the narrowing of the vessels (stenosis) or at worst to its closure (thrombus) are also detected very well. We can judge how strongly the blood flow is hindered by the plaques. Additionally, we can also assess the risk of stroke.
The diagnosis of vascular diseases is difficult: The radiologist has to take the normal vascular conditions with their “standard variants” into account and set them apart from the pathological malformations.
Eye and Nasal Sinuses
The anatomy of the eye and the nose with the corresponding structures can be represented with excellent image quality in the MRI.
MRI Diagnosis of the Eye
The whole-body MRI screening can help to detect early stages of benign or malignant tumors of the eye caves. The vascular situation of the tumor can be represented by the simultaneous administration of contrast agents. The already mentioned diffusion MRI helps to differentiate between the benign or malignant form.
If optic neuritis is detected, the white matter lesions consistent with multiple sclerosis can be noted in MRI.
MRI Diagnostics of the Nose
Nasal sinus inflammation (sinusitis) is annoying and painful. In chronic progression, an MRI can be useful for getting to the bottom of the possible causes.
The shape of the nasal septum can also be very well depicted with the MRI. A nasal septum deviation may restrict the nasal respiration. As the nose can’t function normally (warming up and humidifying the air) the patient is more often affected by infections of the respiratory tract. Other anomalities of the septum can also hinder the flow of air through the nose. The MRI images can be used to assess whether surgical intervention is necessary or not.
Nasal polyps develop from the nasal mucosa and can impede the flow of air due to their spatial demands. They can be detected and localized in the MRI. The attending specialist can make use of the images for further diagnosis and therapy.
As with the eye caves, benign or malignant tumors of the sinuses can be detected on the MRI images. The screening gives us the possibility to identify and classify tissue changes in the sinuses at an early stage – an excellent way of prevention!!!
In this chapter we could only present you a small excerpt of brain and head diagnostics by MRI. Consider this an exemplary representation of selected diseases that can be diagnosed during the whole-body MRIs. Keep in mind that most of the findings do not require any or require minor therapeutic steps.