Ultrasound-based non invasive intracranial pressure
Creators: name: ROBBA, CHIARA
Publisher: name: Universit� degli studi di Genova
Year: 2018

description: Intracranial pressure (ICP) is an important monitoring modality in the clinical management of
several neurological diseases carrying the intrinsic risk of potentially lethal intracranial
hypertension (ICH). Considering that the brain is in an enclosed compartment, ICH leads to
brain hypoperfusion and eventually ischaemia followed by irreversible neuronal damage.
Traumatic brain injury (TBI), for instance, is a condition in which ICH is strongly associated
with unfavourable outcome and death.
Although ICP can guide patient management in neurocritical care settings, this parameter is
not commonly monitored in many clinical conditions outside this environment. The invasive
character of the standard methods for ICP assessment and their associated risks to the patient
(like infections, brain tissue lesions, haemorrhage) contribute to this scenario. Such risks have
prevented ICP assessment in a broad range of diseases like in patients with risk of
coagulopathy, as well as in other conditions in which invasive assessment is not considered or
outweighed by the risks of the procedure. Provided that knowledge of ICP can be crucial for
the successful management of patients in many sub-critical conditions, non-invasive
estimation of ICP (nICP) may be helpful when indications for invasive ICP assessment are
not met and when it is not immediately available or even contraindicated.
Several methods for non-invasive assessment of ICP (nICP) have been described so far.
Transcranial Doppler (TCD), for instance, is primarily a technique for diagnosing various
intracranial vascular disorders such as emboli, stenosis, or vasospasm, but has been broadly
utilised for non-invasive ICP monitoring due to its ability to detect changes in cerebral blood
flow velocity derived from ICP variations. Moreover, TCD allows monitoring of these
parameters as they may change in time.
Optic nerve sheath diameter ultrasonography (ONSD) is another non-invasive tool which
gained interest in the last years. The optic nerve sheath is in continuous with the subarachnoid
space, and when ICP increased, the diameter of ONSD enlarges proportionally to ICP.
The focus of this thesis is on the assessment, applications and development of ultrasoundbased
for nICP assessment in different clinical conditions where this parameter is relevant but
in many circumstances not considered, including TBI and other neurological diseases
ULTRASOUND BASED NON-INVASIVE INTRACRANIAL PRESSURE
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associated with impairment of cerebral blood flow circulation. As main results, ONSD and
TCD-based non-invasive methods could replicate changes in direct ICP across time
confidently, and could provide reasonable accuracy in comparison to the standard invasive
techniques. These findings support the use of ultrasound based non-invasive ICP methods in a
variety of clinical conditions requiring management of intracranial pressure and brain
perfusion. More importantly, the low costs associated with nICP methods, ultrasound
machines are widely available medical devices, could contribute to its widespread use as a
reliable alternative for ICP monitoring in everyday clinical practice.