We present different clinical entities that have been studied in our institution with CTp,
where it provided relevant information to diagnosis and treatment.
Based on the parameters of cerebral perfusion (Fig. 5),
we propose a table for the interpretation of the different maps and their quantitative values,
with the normal and abnormal limits that determine hypo - hyperperfusion,
ischemia,
penumbra and core infarction (Fig. 6).
Crossed cerebellar diaschisis
Crossed cerebellar diaschisis is a depression in neuronal metabolism and activity characterized by decreased brain perfusion in the cerebellar hemisphere contralateral to a supratentorial injure.
Interruption of the cortico-ponto-cerebellar pathway is thought to most likely be the mechanism of remote transneuronal metabolic depression and deafferentation of the contralateral cerebellar hemisphere.
A CTp performed during an acute stroke may show a contralateral cerebellar perfusion abnormality in about 20% of cases,
in particular hypoperfusion.
In case 1 we present a patient with supratentorial infarcts and crossed cerebellar diaschisis (Fig. 7,
Fig. 8).
In chronic stages,
there can be associated volume loss to the contralateral cerebellar hemisphere,
known as crossed cerebellar atrophy.
Intracranial vasculitis
Heterogeneous group of CNS disorders,
characterized by non-atheromatous inflammation and necrosis of the vessel walls.
It is classified in two groups,
primary or secondary, depending on whether or not there is evidence of systemic vasculitis.
The imaging findings can be primary (intracranial vessel wall) and secondary (stenosis,
ischemia,
hemorrhages and perfusion alterations).
CTp provides crucial information about brain hemodynamic state,
specially in the identification of tissue that is ischemic and potentially at risk for infarction.
In case 2 we present a patient with infectious vasculitis and secondary cerebral hypoperfusion (Fig. 9,
Fig. 10).
Cerebral revascularization studies
Cerebral revascularization is a useful microsurgical technique for the treatment of steno-occlusive intracranial ischemic disease,
complex intracranial aneurysms that require occlusion of a proximal artery and invasive skull base tumors.
The CTp studies are useful to determine the success of the procedure and monitoring evolution.
In case 3 we present a patient with revascularizated Moyamoya disease (Fig. 11,
Fig. 12).
Tumors
Brain perfusion studies are useful to differentiate neoplastic from non neoplastic pseudotumoral lesions.
The former with elevated CBV and the latter with decreased CBV.
In cerebral gliomas CTp is useful to estimate the tumor grade according to the vascular behavior: high grade gliomas are associated with neovascularization and immature vessels that results in increased blood volume and permeability.
This fact explains the rule that higher grade tumors tend to have higher CBV values.
An exception to this rule are oligodendroglioma and pylocitic astrocytoma.
In case 4 we present a low grade astrocitoma (Fig. 13,
Fig. 14) and in case 5 a glioblastoma (Fig. 15,
Fig. 16).
CTp is also a useful tool to evaluate treated tumors and distinguish between radionecrosis and tumoral recurrence.
Post-convulsive hemodynamic changes
In the setting of seizures,
CTp maps may show hyperperfusion in the affected cortical regions,
wich allows differentiates convulsive status from stroke.
In case 6 we present a patient with convulsive status and secondary hyperperfusion (Fig. 17,
Fig. 18).