Brain CT Flashcards
a. Hyperdense lesion affecting the right thalamus
b. Hyperdense lesion affecting the right putamen
c. Hyperdense lesion affecting bilateral lateral ventricles
d. Right-sided convex hyperdense lesion
a. Acute subdural haematoma with ventricular extension
b. Intracerebral haemorrhage with ventricular extension
c. Subarachnoid haemorrhage
d. Intracerebral tumor with ventricular metastasis
b. Intracerebral haemorrhage with ventricular extension
Hemorrhages within the ventricles commonly occur as an extension from an underlying intracerebrasl hemorrhage (espeically those involving the thalamus and basal ganglia). They can also occur in isolation (as a result of underlying hypertensive angiopathy), or due to vascular lesions (e.g. cerebral aneurysms, AVM, moyamoya disease), coagulopathies and intraventricular tumors.
c. incorrect
a. Cerebral amyloid angiopathy
b. Hypertension
c. Saccular aneurysm
d. Head injury
b. Hypertension is the most common cause of cerebral small vessel disease and can lead to hypertensive angiopathy. A small number of pathological cahnges occur in the blood vessels including lipohyalinosis, arteriosclerosis and microaneurysm formation. These changes in the blood vessels make them more vulnerable to occlusion, resulting in lacunar infarcts; but also to rupture, resulting in intracerebral hemorrhages. Intracerebral hemorrhages secondary to hypertension are usually deep seated, involving structures such as the thalamus, internal capsule, basal ganglia, brainstem, cerebellum.
c. incorrect as saccular aneurysms are most common cause of spontaneous subarachnoid hemorrhage
d. incorrect –> head injury can lead to a variety of intracranial hemorrhages, including epidural haematomas, subdural haematomas, subarachnoid hemorrhages and hemorrhagic contusions. Hemorrhagic contusions typically involve the inferior frontal and anterior temporal lobes.
a. Blood pressure control
b. Carotid endarterectomy
c. Anticoagulation
d. Craniotomy
A. correct. BP is reaised in 70% of patients presenting with stroke. In patients with acute intracerebral hemorrhage, acute lowering of systolic BP to a targeet of 140mmHg with the goal of maintaining in the range of 130-150mmHg is recommended.
b. incorrect. Carotid endarterectomy is considered in patients with severe carotid stenosis presenting with a TIA or ischemic stroke
c. Incorrect. Anticoagulants for TIA or ischemic stroke due to cardioembolic cause (e.g. AF or in patients with underlying mechanical heart valve) and will not usually be prescribed in patients with an intracerebral hemorrhage, especially when already bleeding.
d. Incorrect. Most patients with supratentorial intracerebral hemorrhage do not require surgical treatment. In selected patients with a supratentorial intracerebral hemorrhage who are deteriorating, craniotomy for haematoma evacuation may be considered as a lifesaving measure. Patients with large cerebellar intracerebral hemorrhage who are deteriorating neurologically, have evidence of brain compression, and/or hydrocephalus from ventricular obstruction, immediate surgical removal of hemorrhage is recommended in preference to medical Mx alone to reduce mortality
What is seen?
Right sided convex (lens shaped) hyperdense lesion with midline shift
dx?
non contrast CT scan of intracerebral hemorrhage with ventricular extension
dx?
Subarachnoid hemorrhage: high density material that fills the subarachnoid space as shown in non contrast CT scan
dx?
Acute subdural haematoma
dx?
Acute epidural haematoma
This characteristic shape arises as the periosteal dura, which is tightly adherent to the inner skull, is stripped away from the inner skull. Also, as the dura is tightly attached to sutures, epidural haematomas rarely cross suture lines. In contrast, subdural haematomas can freely cross suture lines.
Can tumor cause epidural bleed?
Intracranial malignancy (primary or secondary) may be complicated with bleeding (hemorrhagic intracranial tumors or tumor bleed), it does not occur in the epidural space
Hypodensity affecting the right middle cerebral artery territory
dx?
hypodensities affecting the anterior cerebral artery territory bilaterally
dx?
non-contrast CT scan shows hypodensity affecting the left posterior cerebral artery territory
dx?
non-contrast CT scan shows hypodensity affecting the cortical watershed zones bilaterally. These watershed areas are where the terminal vasculature of the anterior cerebral artery and middle cerebral artery meet, as well as where the middle cerebral artery and posterior cerebral artery meet.
dx?
Chronic infarct. The left ventricle is dialted (ex vacuo dilatation: open arrow) because there is volume loss of the surrounding brain parenychma, and the ventricle expands into this space. Look for volume loss of brain and ex cavuo dilatation of ventricles to help distinguish chronic from acute/subacute infarcts.
dx?
Subacute right MCA territory infarction (2-14 days old infarct)
Post stroke epilepsy occurs in approx 5% of stroke patients. Swelling associated with the infarct compresses the right lateral ventricle and effaces the sulci on the right (in contrast to the left lateral ventricle and left cerebral sulci which are easily appreciated).
dx?
Acute (hours old) right MCA infarct. There is reduced grey white differentiation and sulcal effacement of the cerebral cortex supplied by the MCA. Note that the density in the MCA territory in this CT image of acute infarct is much higher than the cerebrospinal fluid density (in the ventricles).
dx?
Acute right MCA complicated by severe cerebral edema and hemorrhagic transformation
A: signficant mass effect and midline shift
B: caused by severe cerebral edema
C: urgent craniectomy done to relieved ICP as evident by absence of skull bone
How to manage the patient?
- In view of the underlying large cortical infarct, this patient is at a high risk of recurrent seizures and anti-seizure medications (e.g., phenytoin, sodium valproate, lamotrigine, levetiracetam etc.) should be considered to control and prevent recurrent seizures. Most seizures abort spontaneously;
- however, should the patient present with another seizure lasting > 2 minutes, benzodiazepines (e.g., lorazepam, diazepam, or midazolam) that is most often given intravenously or intramuscularly can be administered to abort the seizure.
What is dx?
Mass lesion (s) in the right frontal lobe
Vasogenic edema
Vasogenic oedema commonly occurs secondary to an underlying brain malignancy. It affects the white (central in brain) but not the grey matter, and hence the hypodensity appears as “finger-like projections” on CT. In contrast, cytotoxic oedema (e.g., due to stroke) involves both the grey and white matter.
dx?
Non contrast CT showing a solitary, small, well demarcated, round, hyperdense lesion which is adherent to the dura, all of which are typical features of meningioma. Calcification can sometimes be seen on CT, as in this case.
dx and appearance?
non-contrast CT image is from a patient with an acute right middle cerebral artery infarct. There is reduced grey-white differentiation and sulcal effacement at the right cerebral artery territory. The cytotoxic oedema as a result of the ischaemic stroke can be seen to involve the grey and white matter (in contrast to just the white matter being involved in the case illustrated with vasogenic oedema). Patients usually presents with acute onset of symptoms in acute ischemic stroke.
dx?
non-contrast CT scans of a patient with severe Alzheimer’s dementia, which shows generalised cortical atrophy as indicated by the generalised widening of sulci (Fig. 1). In particular, the medial temporal lobes are particularly affected (Fig. 2).
a. Dexamethasone
b. MRI brain with contrast
c. Oncology consultation
d. Brain radiotherapy
All correct.
Vasogenic oedema secondary to brain tumours is the result of leakage of plasma into the parenchyma through dysfunctional cerebral capillaries.
* Corticosteroids decrease vasogenic edema and are often administerd IV in patients who present acutely. Can be changed to tapering oral formulation
* Contrast enhanced MRI brain is much more sensitive that non contrast CT scan for detecting intracranial metastases
* Oncology consultation recommended to determine most suitable management strategy as patients with brain metastases often will benefit from whole brain radiotherapy
4th ventricle (immediately anterior to the cerebellum) is compressed. This hinders CSF drainage, leading to obstructive hydrocephalus and subsequent dilatation of the third and lateral ventricles.
Subarachnoid hemorrhage. Reflects extravasation of blood into the space between the arachnoid mater and pia mater. This non-contrast CT scan shows high-attenuation material filling the basal cisterns and ventricles. This is typical of subarachnoid haemorrhage. Normally these spaces are filled with CSF and appear dark on the non-contrast CT scan.
dx and cause?
Subdural haematoma due to accumulation of blood between the dura mater and arachnoid mater. This is most often due to head injury resulting in a tear of the bridging cortical veins as they cross the subdural space to enter a dural venous sinus.
CT angiogram: high sensitivity, rapid scan time and around the clock assessibility. In patients with negative CT angiogram, a digital subtraction angiography (DSA: gold standard) may be required to exclude a small aneurysm resulting in the subarachnoid hemorrhage.
In patients with delayed presentation of a subarachnoid hemorrhage, the sensitivity of CT at detecting blood in the subrachnoid space decreases. In these cases, a lumbar puncture should be done to detect for any xanthochromia (its presence may signify a recent bleed into the subarachnoid space)
- Intubation: patient has poor GCS 6/15 –> protect the iarway
- BP control: severely hypertensive and at risk of rebleeding and end organ damage. IV antihypertensive agents e.g. labetolol, nicardipine or nimodipine (CCB), hydralazine (smooth muscle relaxant).
- Prevent cerebral vasospasm and ischemic stroke. Cerebral vasospasm can occur several days after subarachnoid hemorrhage (peaks at day 4-7) and can lead to cerebral ischemia. CCB (nimodipine) given IV initially then orally, are often used to prevent vasospasm after subarachnoid hemorrhage.
- Treat underlying cerebral aneurysm: endovascular coiling or surgical clipping of the aneurysm can be performed. The need to insert an external ventricular drain to reduce and monitor the ICP can also be assessed
Blood tests for INR.
The patient is receiving warfarin (vitamin K antagonist) for prevention of thromboembolic events secondary to underlying atrial fibrillation. Checking the INR (international normalised ratio) will be useful to assess the coagulation status in patients taking warfarin. A higher INR value is associated with increased risk of intra- and extracranial bleeding. Therefore, it should be arranged for this patient urgently to guide the next step in management.
- Stop warfarin
- Reversal of anticoagulation (IV vit K and prothrombin complex concentrate)
- Neurosurgical consultation (potentially evacuate the clot to minimize secondary brain damage and to alleviate raised ICP)
dx?
patient has bilateral chronic subdural haematomas, which are now hypodense and approaching the density of cerebrospinal fluid.
dx?
non-contrast CT of a patient with bilateral subacute subdural haematomas. The haematoma on the right side is isodense . On the left side, however, there is a mixture of densities – the upper part being relative isodense, whilst the lower part hypodense . Such a mixed pattern is not uncommon and is usually due to recurrent haemorrhage into a pre-existing subdural haematoma (often due to repeated falls and head injuries in an elderly patient), hence resulting in a mixture of densities.
