From the Guidelines
An MRI of the brain and an MRI of the head are not exactly the same, though they are related, with the key difference lying in their scope and the structures they image. An MRI brain specifically focuses on imaging the brain tissue itself, examining structures like the cerebrum, cerebellum, brainstem, and looking for abnormalities such as tumors, strokes, inflammation, or degenerative changes 1. On the other hand, an MRI head is a broader examination that includes the brain but also captures surrounding structures like the skull, sinuses, orbits (eye sockets), facial bones, and soft tissues of the head.
The distinction between these two types of MRI scans matters clinically because physicians order them for different purposes. For instance, a brain MRI is typically ordered when there is a concern specifically about brain pathology, such as in the case of persistent neurologic deficits that remain unexplained after a head CT 1. In contrast, a head MRI is ordered when there is a need to evaluate both the brain and the surrounding head structures, which can be crucial in the assessment of head trauma, where subtle findings adjacent to the calvarium or skull base may be present 1.
Some key points to consider when deciding between an MRI brain and an MRI head include:
- The sensitivity of MRI for detecting subtle findings, such as small cortical contusions and subdural hematomas, especially in cases of traumatic brain injury 1.
- The ability of MRI to detect small white matter lesions in traumatic axonal injury or DAI, which may not be visible on CT scans 1.
- The clinical context, including the presence of persistent neurologic deficits or the need for long-term prognostication in patients with mild TBI and normal CT scans 1.
In terms of morbidity, mortality, and quality of life, the choice between an MRI brain and an MRI head should be guided by the specific clinical question being asked and the potential impact of the diagnostic findings on patient management and outcomes. Ultimately, the decision to order an MRI brain or an MRI head should be based on a thorough clinical evaluation and a consideration of the potential benefits and limitations of each type of scan.
From the Research
MRI of the Brain vs. MRI of the Head
- An MRI of the brain and an MRI of the head are not exactly the same, although they can be related 2, 3.
- An MRI of the brain is focused on the brain tissue and is used to diagnose and monitor conditions such as brain tumors, multiple sclerosis, and traumatic brain injury 2, 4, 5, 6.
- An MRI of the head, on the other hand, can include the brain, but also other structures such as the skull, sinuses, and facial bones 3, 4.
- The key difference between the two is the scope of the imaging and the specific conditions being diagnosed or monitored.
Imaging Modalities and Techniques
- MRI is a sensitive imaging modality for identifying inflammatory and/or demyelinating lesions, which is critical for a clinical diagnosis of MS and evaluating drug responses 5, 6.
- Different MRI sequences and techniques can be used to visualize and quantify lesions, including T1 and T2 weighted imaging, T2 fluid attenuated inversion recovery (FLAIR), magnetization transfer, myelin water fraction, diffusion tensor imaging (DTI), and susceptibility weighted imaging (SWI) 6.
- The choice of imaging protocol can depend on the specific condition being diagnosed or monitored, as well as the need to reduce redundancy of information and alleviate patient burden 6.
Clinical Applications
- MRI is a valuable tool in the clinical management and scientific investigation of multiple sclerosis (MS) and has become the most important ancillary tool for diagnosing and monitoring the disease 5.
- MRI can be used to assess overt lesions and atrophy in the central nervous system, as well as to evaluate the presence of an altered blood-brain barrier and abnormal calcification 2, 4.
- In cases of traumatic brain injury, MRI may be as sensitive as CT scanning in the detection of intracranial findings, but may miss skull fractures 4.