Lexington Forensic Neuropsychiatry

Printer-friendly VersionNeuroimaging

If good quality structural or functional films of patients are available prior to examination at Lexington Forensic Psychiatry, we will generally ask that those films be copied for our use. If, on the other hand, there has been a significant interval between prior imaging and our examination, we will probably order our own imaging.

Magnetic resonance imaging (MRI) is not invasive and is well tolerated by patients. It is easily performed as an outpatient procedure. It is the best structural imaging for measuring long term nervous tissue effects. There are no known adverse biologic effects and magnetic resonance imaging is more sensitive than CT scanning. T-1 weighted images provide excellent anatomic correlation and T-2 images allow the detection of lesions that would not otherwise be seen on CT scanning. FLAIR weighted images remove artifact from cerebrospinal fluid, gradient echo weighted images can detect old blood (hemosiderin), and diffusion weighted images (DWI) can detect ischemia.

Click to EnlargeFigure 1
This is a 37-year-old male who was thrown from a man lift and struck his head on the pavement resulting in multiple skull fractures and bilateral subdural hematomas. He required neurosurgical treatment at a university medical center. Figure 1 demonstrates encephalomalacia (dead or soft brain tissue) on a T2 weighted MRI in the inferior right temporal lobe. The east facing arrow delineates this lesion.

Click to EnlargeFigure 2
This is a 61-year-old male who fell from a scaffold to concrete 35 years prior to this image. The south facing arrow delineates a thinning of corpus callosum. These are crossing fibers from the right and left side to the brain and as a result of his injury he had destruction to white matter fibers in this brain area.

Click to EnlargeFigure 3
This is a FLAIR MRI of a gentleman who had prolonged exposure to toluene diisocyanate (TDI) while employed unloading tank cars containing this substance. He developed an encephalopathy with an emotional component and the white matter lesions represent injured brain tissue from solvent exposure.

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This is a lady who claimed brain injury from a bus accident. She was found to have an old lacunar infarct in the right basal ganglia delineated by the east facing arrow. This FLAIR MRI also demonstrates atrophy of the brain and evidence of significant periventricular deterioration around the posterior lateral ventricles as noted by the white areas indicated by the north facing arrows. She was found to have been demented at the time of the alleged bus accident.

Click to EnlargeFigure 5
This demonstrates the MRI of a 19-year-old young man who was involved in a rollover automobile accident. The area delineated by the west facing arrow represents diffuse axonal injury of crossing fibers in the posterior corpus callosum.

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This demonstrates hemosiderin deposits from prior hemorrhage sustained by a 39-year-old woman who was a passenger in a vehicle struck by a cement truck. The dark areas delineated by the arrows are loss of signal as a result of iron deposits left behind by prior bleeding. These iron deposits are termed hemosiderin.

Click to EnlargeFigure 7
This demonstrates an elderly person with cortical atrophy and bilateral hippocampal atrophy. This person is demented. This is a T2 coronal MRI sequence, which is the most useful sequence to detect hippocampal atrophy.

Computed tomography (CT) is also a structural scan. It is generally the scan of choice for acute evaluation of brain injuries. Since Lexington Forensic Psychiatry generally is evaluating individuals for potential brain injury well after the fact, CT scanning of the brain is generally reserved for those persons who cannot submit to magnetic resonance imaging because of ferromagnetic materials in their body, or where it is necessary to look at the skull as well as the brain.

Click to EnlargeFigure 8
This is a CT image of a person made after boxes fell and struck his head in a distribution center. He is a 50-year-old male who complained of traumatic brain injury as a result of his accident. In reality, he suffers from Fahr’s disease, a disorder of bilateral basal ganglia calcification and psychosis. Calcium is best detected by CT rather than an MRI.

Click to EnlargeFigure 9
This acute CT represents blood within the left brain following a gunshot wound to the top of the head. The south facing arrow depicts the blood. Notice the halo around the white area. The darker halo represents edema of surrounding brain tissue and injury due to the concussive effects of the bullet entering the brain tissue. Also notice the thin line separating the left and right hemispheres. This line (the falx) is a tight fibrous tissue. One can see the pressure effect bowing the falx toward the right side of the brain (remember that on x-rays, left is on the viewer’s right). Moreover, the left skull has been surgically removed to save the individual’s life due to the pressure effects.

Click to EnlargeFigure 10
This demonstrates one of the useful properties of CT. Three dimensional reconstruction of bone can be made. This case represents a 20-year-old college student who sustained a head-on collision while traveling home from college. The west facing arrow shows a loss of bone from the upper palate (maxilla). The north facing arrow demonstrates fragments of the hard palate and incisor teeth. There is an appliance noted in the right lower quadrant, which is holding her facial structures in place while the CT image is obtained.

Click to EnlargeFigure 11
This is a CT image made of a gentleman’s brain shortly after he fell at work. He was alleging a traumatic brain injury when in fact the CT image confirms that he had a bilateral hemorrhagic stroke in the anterior brain, which caused him to fall. The stroke was unrelated to the fall.

Click to EnlargeFigure 12
This is a CT demonstrating encephalomalacia. It is the outcome of the facial injury depicted in figure 10. This is a striking demonstration that severe facial trauma can lead to brain injury in the absence of skull injury.

Magnetic resonance spectroscopy (MRS) is a technique wherein chemicals can be measured in the brain while a person is in the magnetic resonance scanning system. Chemicals related to brain integrity and brain function can be measured noninvasively by this magnetic method. These chemicals include: N-acetylaspartate, creatine, choline, myoinositol, lipids, and glutamate and glutamine.

Click to EnlargeFigure 13
This depicts an MRI of the brain with a superimposed MRS. The east facing arrow points to the area of interest, a lesion (the white area) due to trauma in the right frontal pole.

Click to EnlargeFigure 14
This is a different person from figure 13 who underwent MRS. The spectroscopy chart indicates relative values of the chemicals that were measured.

Positron Emission Tomography (PET) utilizes F-18-deoxyglucose as a radioactive tracer. The brain treats this compound as if it were serum glucose. Therefore, the patient fasts for at least four hours prior to the administration of the F DG as FDG competes with serum glucose for brain accumulation.

FDG-PET scans produce brain images of metabolic activity in brain tissue. Thus, this is a functional, rather than a structural, scan of the brain. Static images are obtained which are converted to single slice displays in the transverse, sagittal and coronal views. The tomograms are attenuation corrected.

Click to EnlargeFigure 15
21-year-old male riding as an unrestrained passenger in a vehicle struck by a 10-wheel coal truck. He suffered severe closed head injury, brain edema, and traumatic brain injury. This coronal image reveals hypometabolic activity in the right thalamus.

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This is a transverse view of the above PET image that again indicates hypometabolic activity in the right thalamus.

Click to EnlargeFigure 17
This represents the raw PET scan data from the young woman depicted in figures 10 and 12. The PET scan correlates exactly with the areas of encephalomalacia in figure 12. Also noted is a significant loss of activity (hypometabolism) in the right inferior temporal lobe. The east and west facing arrows depict frontal hypometabolism that corresponds to figure 12, whereas the north facing arrow depicts the inferior temporal lobe hypometabolism on the right, which is not evident on the particular section of CT displayed on figure 12.

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