Neuro Radiology Flashcards
(69 cards)
What is going on in this patient’s noncontrast CT?
This is also subarachnoid hemorrhage, it is just at a lower level!
Don’t let them trick you by giving you an out-of-frame view of a subarachnoid hemorrhage
What is going on in this patient’s noncontrast CT?
To be honest this is tricky, it looks a lot like a single calcified mass.
But this particular patient has an intraventricular hemorrhage. These occur due to tearing of subependymal veins.
The best place to look for intraventricular hemorrhage is in the occipital horns of the lateral ventricles. Commonly associated with injury to the corpus callosum. It should be noted that the choroid plexus often calcifies and thus can look quite dense, and should not be mistaken for intraventricular hemorrhage.
What is going on in this patient’s noncontrast CT?
This patient has intraparenchymal hemorrhage
It can be due to trauma as well as other causes such as hypertensive hemorrhage, a hemorrhagic stroke, a ruptured AVM, or a hemorrhagic neoplasm.
Major causes of the five main types of head bleed (epidural, subdural, subarachnoid, intraventricular, intraparenchymal)
- Epidural: Middle meningeal artery tear
- Subdural: Bridging vein tear
- Subarachnoid: Ruptured aneurysm
- Intraventruclar: Subependymal vein tear
- Intraparenchymal: No specific vessel, often in setting of trauma
Note that of all of these, only epidural and subarachnoid are arterial bleeds
What is going on in this C-spine CT?
Spinous process facture, aka Clay Shoveler’s fracture
An avulsion of the spinous process due to pulling from the trapezius muscle. Treatment consists of pain medication and physical therapy.
Five low-risk criteria for C-spine imaging
- C-spine imaging is required in all blunt trauma cases unless the patient meets all of these criteria:
- Absence of posterior midline cervical-spine tenderness
- No evidence of intoxication
- Normal level of alertness
- Absence of focal neurological deficit
- No clinically apparent painful injuries that might distract from pain of a cervical spine injury
Why is it subarachnoid hemorrhage specifically that can cause vasospasm?
Because subarachnoid hemorrhage surrounds cerebral blood vessels.
This is usually seen in the setting of diffuse subarachnoid hemorrhage secondary to ruptured aneurysm rather than trauma, and typically manifests several days after the subarachnoid hemorrhage has occurred
What is going on in this MRI?
Diffuse axonal injury with blurring of the gray-white junction and small foci of petechial hemorrhage in white matter tracts
CT is not very sensitive for detecting DAI – MRI is required for diagnosis.
What is going on in this noncontrast CT?
Acute subdural hemorrhage
You can tell it is acute because the blood is bright
What is going on in this noncontrast CT?
Chronic subdural hemorrhage
You can tell by the color of the coagulated and fibrosing blood. This bleed has been maturing for at least 3 weeks to obtain this apperance.
What is going on in this noncontrast CT?
This one is really tough. Based on the ventricles, you can tell that there is a mass lesion, but it is almost impossible to differentiate from the gray matter of the cortex.
This is a subacute subdural hemorrhage. In the process of maturation, from ~3 days - 3 weeks, this is how a subdural hemorrhage will appear – isodense with gray matter.
Often your clinical suspicion for subacute SDH should be triggered when there is evidence of mass effect and altered mental status, but the CT generally looks normal except that the gray matter looks too thick.
Major brain fissures and sulci
Normal saggital T1 weighted midline brain MRI
For orientation purposes, anterior is to your left (A). The corpus callosum (CC) is located superiorly. The pituitary gland (P) sits in the sella turcica and connects to the hypothalamus via the pituitary stalk or infundibulum ( dotted white arrow ). The mammillary bodies (M) are located anterior to the brainstem. The cerebral aqueduct ( solid white arrow ) is superior to the midbrain. The brainstem is composed of the midbrain (Mi), the pons (Po), and the medulla (Me). The fourth ventricle (4) communicates with the cerebral aqueduct and lies between the cerebellum (Ce) and the brainstem.
Axial MRI T1/T2 of deep gray structures in the brain
Axial T1-weighted (A) and T2-weighted (B) images of the brain demonstrate that CSF in the lateral ventricles is dark on T1 and bright on T2 ( solid black arrows ).
Gray matter, which contains the neuronal cell bodies, is actually gray on T1-weighted images ( open white arrow ) and white matter, which contains myelinated axon tracts, is whiter ( white circle ). The caudate nuclei ( solid white arrows ) and lentiform nucleus ( dotted white arrows ) together form the basal ganglia. The thalamus ( dotted black arrows ) is located posterior to the basal ganglia.
Lentiform nucleus
The lentiform nucleus is composed of the putamen (laterally) and globus pallidus (medially).
Finding the caudate, thalamus, and lentiform nucleus
What is going on in this saggital MRI?
A pineal gland tumor is seen compressing the midbrain and other surrounding structures
Finding the pineal gland
It is easiest to find on saggital view, but can be found axially by finding the top of the cerebellum and looking just anteriorly
Occasionally there will be benign pineal calcifications
You’re not going to see a skull fracture unless you. . .
. . . put on the bone window
Blow-out fracture
Most common fracture of the orbit. Caused by direct eye trauma.
It is a fracture of the inferior orbital floor leading into the maxillary sinus, or the medial wall of the orbit leading into the ethmoid sinus. Sometimes this fracture produces inferior rectus entrapment syndrome (restriction of upward gaze, diplopia).
Helpful signs to suggest this fracture may include: orbital emphysema, apparent soft tissue/fat entrapment in the superior maxillary sinus, blood in the maxillary sinus.
Tripod fracture
Another common eye fracture. Usually the result of blunt force to the cheek
Involves separation of the zygoma from the remainder of the facial bones by separation of the frontozygomatic suture, fracture of the floor of the orbit, and fracture of the lateral wall of the ipsilateral maxillary sinus
Almost all epidural hematomas (>95%) have. . .
. . . an associated skull fracture
Often in the temporal bone
In contrast, subdural hematomas usually are not.
Vasogenic edema affects ___.
Cytotoxic edema affects ___.
Vasogenic edema affects primarily white matter. White-gray differentiation is preserved.
Cytotoxic edema affects white matter and gray matter. White-gray differentiation is often lost.
60% of hypertensive hemorrhagic strokes occur in . . .
. . . the basal ganglia
