There are several advanced MRI techniques for more sophisticated imaging of brain structure and function. The most common advanced imaging techniques include spectroscopy, perfusion, diffusion tensor imaging (DTI), and functional MRI (fMRI). This playlist shows some of the details of using advanced imaging techniques for brain imaging and surgical planning.
This playlist includes some of the details about using advanced MRI for surgical planning and determining additional details about brain MRI.
Functional MRI (fMRI) language localization – conjunction display
Blood oxygen level dependent functional MRI, or BOLD fMRI, is an advanced MRI technique in which level of oxygen present in an area of the brain is used to map out what parts of the brain are activated in specific tasks. In this method, repeated imaging of the brain can be performed while the patient performs a task, and the level of oxygenation changes, showing which parts of the brain are most activated.
A key application of fMRI is mapping of language areas, or language localization, for surgical planning. The patient will perform more than 1 language task while in the scanner, and the activation data is overlaid on anatomic imaging (like conventional T1 or T1 postcontrast imaging). This is used to determine which side of the brain is language dominant as well as where exactly important language areas, including Broca’s and Wernicke’s areas, are located. This way they can be avoided in complex surgical procedures. However, sometimes results can be difficult to interpret because of the high number of images and high amounts of noise.
In this video, Dr. Michael Hoch demonstrates how use a conjunction technique to increase sensitivity for mapping language areas. In this method, all the language paradigms are overlaid on a single set of images using different colors. This increases the visibility of otherwise hard to see areas, increasing reader confidence.
The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in advanced MRI techniques such as diffusion tensor imaging (DTI) tractography, functional MRI (fMRI), and surgical planning.
Blood oxygen level dependent functional MRI, or BOLD fMRI, is an advanced MRI technique in which level of oxygen present in an area of the brain is used to map out what parts of the brain are activated in specific tasks. In this method, repeated imaging of the brain can be performed while the patient performs a task, and the level of oxygenation changes, showing which parts of the brain are most activated.
A key application of fMRI is mapping of language areas, or language localization, for surgical planning. The patient will perform more than 1 language task while in the scanner, and the activation data is overlaid on anatomic imaging (like conventional T1 or T1 postcontrast imaging). This is used to determine which side of the brain is language dominant as well as where exactly important language areas, including Broca’s and Wernicke’s areas, are located. This way they can be avoided in complex surgical procedures. However, sometimes results can be difficult to interpret because of the high number of images and high amounts of noise.
There are a number of processing suites that you can use to process fMRI data, including Brainlab and Dynasuite. The processing can be slightly different depending on which software package you are using, but the general principles are the same. To begin, you take each functional paradigm and overlay it on anatomical imaging, selecting statistical parameters and colormapping as you go.
In this video, Dr. Michael Hoch demonstrates the use of Brainlab to process fMRI data for language processing. He goes through the step-by-step process of generating each set of overlay imaging and how to interpret the results. In the second part of the video, he demonstrates conjunction overlay technique to increase sensitivity for mapping language areas by showing only the areas which have overlapping results on multiple paradigms, increasing reader confidence.
The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in advanced MRI techniques such as diffusion tensor imaging (DTI) tractography, functional MRI (fMRI), and surgical planning.
Diffusion tensor imaging, or DTI, is an advanced MRI technique in which the asymmetric motion of water is used to map out specific properties in the brain. One application of DTI is called tractography, or identifying the specific tracts of neurons which pass through the brain.
One of the most important fiber tracts in the brain is the corticospinal tract, or CST. This tract connects the motor cortex with the spinal cord, passing through the cerebral peduncles. This fiber tract is important because it is the tract most responsible for voluntary movement. It can be affected by a number of pathologies, such as tumors, cortical malformation, and stroke. For some conditions, such as tumors, it can be critically important to locate the CST before performing surgery, so that the surgeons can properly plan their surgery. That’s where DTI comes in.
In this video, Dr. Michael Hoch demonstrates how to use a two region of interest method to identify the corticospinal tract, first placing a region of interest in the cerebral peduncle and a second in the motor cortex. He also talks about some of the pitfalls of diffusion tensor imaging and what kind of problems to look out for.
The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in advanced MRI techniques such as diffusion tensor imaging (DTI) tractography, functional MRI (fMRI), and surgical planning.
Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.
More description and the answer (spoiler!) are seen below the video.
This case shows a mass within the spinal canal of the upper thoracic spine. For any spinal canal mass, your first step is to determine if it is:
intramedullary (in the spinal cord)
intradural extramedullary (inside the dura, but outside the spinal cord)
extradural
This mass appears to be extramedullary but intradural. The main differential considerations are meningioma, nerve sheath tumor/schwannoma, or metastasis. This mass has a relatively benign appearance and enhances avidly and homogenously.
The diagnosis is: meningioma
Spinal meningiomas are extramedullary masses that share an imaging appearance with intracranial meningiomas. They are often homogenous and enhance avidly. They can have calcification. The treatment, if symptomatic, is surgical resection.
Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.
More description and the answer (spoiler!) are seen below the video.
This case shows a trauma patient who had a significant fall and now has lower extremity symptoms. On the MRI, there are a few compression fractures that you can see, but in addition there is T1 hyperintense fluid in the dorsal epidural space. In the setting of trauma, this is likely to be an epidural hematoma.
The diagnosis is: fracture with spinal epidural hematoma
Epidural hematoma is a dreaded complication of spine trauma that can cause worsening cord injury. It requires close monitoring and possibly surgical drainage if this may improve the symptoms. Look for intraspinal fluid collections after trauma, as they can be hard to identify.
Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.
More description and the answer (spoiler!) are seen below the video.
This case shows a patient with a new neurologic deficit and a relatively normal noncontrast head CT. Perfusion, on the other hand, shows an area of decreased CBV, increased MTT, and increased Tmax in the posterior aspect of the left middle cerebral artery (MCA) distribution. There is an associated vessel occlusion on CT angiogram.
The diagnosis is: cerebral ischemia (stroke)
This patient has an area of ischemia in the left MCA territory. Because the CBV is relatively maintained, this tissue is mostly considered penumbra. When there is a significant decrease in volume and flow, it is considered core infarct that is not likely to recover.
Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.
More description and the answer (spoiler!) are seen below the video.
This case shows an aggressive lesion of the upper thoracic spine in a relatively young patient. It appears to be centered in the posterior elements of the upper thoracic spine. There is central osseous matrix formation as well as a surrounding soft tissue mass with adjacent bone destruction. This is causing significant narrowing of the spinal canal.
The diagnosis is: osteosarcoma
In this case, you know you are dealing with an aggressive mass because of the soft tissue component and bone destruction. The differential includes primary bone lesions, metastatic disease, and lymphoma, but because of the new bone formation (osteoid matrix), it suggests osteosarcoma.
This playlist is a collection of only the head and neck imaging board review cases on this site. This includes pathologies such as head and neck cancer and skull base abnormalities.
These cases are geared towards preparation for the radiology resident ABR core exam, although similar material is used for the ABR certifying exam general and neuroradiology sections as well as neuroradiology CAQ. The format of this playlist is case-based. Each case consists of a series of images followed by 1 or 2 questions. The first question is usually to name the diagnosis, while the second is a multiple choice question to test deeper understanding of the specific condition. Try to get the diagnosis before you see the second questions.
This playlist is a collection of only the spine imaging board review cases on this site.
These cases are geared towards preparation for the radiology resident ABR core exam, although similar material is used for the ABR certifying exam general and neuroradiology sections as well as neuroradiology CAQ. The format of this playlist is case-based. Each case consists of a series of images followed by 1 or 2 questions. The first question is usually to name the diagnosis, while the second is a multiple choice question to test deeper understanding of the specific condition. Try to get the diagnosis before you see the second questions.
