We retrospectively recruited all consecutive patients with acute ischemic stroke who were possible candidates for thrombolysis and underwent advanced imaging including both CTP and CTA.
In our hospital,
all candidates are always evaluated with NCCT,
CTP,
and CTA.
We recruited both anterior and posterior circulation strokes.
The CT scanner was a 64-section Philips Brilliance (Philips Healthcare,
Cleveland,
Ohio,
USA).
A pre-contrast study of the whole brain was always performed.
Subsequently CTP data were acquired in brain parenchyma area measured from the upper limit of the fourth ventricle to the centrum semiovale.
A 50-mL intravenous bolus of 370 mg/dL nonionic iodinated contrast agent followed by 40 mL of saline was administered; finally,
a 5-s delay after initiation of the injection a cine (continuous) scan was initiated.
CTP data were analyzed using Philips Brain Perfusion software.
All NCCT scan were read by a vascular neurologist,
expert in the field of cerebrovascular disease,
with a background of clinical trials involving radiological evaluation [8,
9].
He was blind to clinical event and to the official reports at the time of the NCCT readings.
For all patients we collected personal history (vascular risk factors,
modified Rankin Scale or mRS),
clinical examination (neurological deficit,
NIHSS) (Table 1) and all the NCCTs were re-read in order to assess the ASPECT score,
as well as the presence of either dense artery sign or any dot sign (Table 2) [10].
Likewise,
old infarcts and leukoraiosis (LA) were documented as well [9,11].
The interpretation of CTP was reassessed from the original images by the neuroradiologist (AC) (the NCCT reader was blinded to the CTP results) and the CTP maps are used to identify infarct core,
total hypoperfusion,
and CTP mismatch.
After the neuroradiological analysis,
every single case underwent an expert-opinion step.
The complete clinical data was presented to the vascular neurologist who was asked for his first opinion,
knowing only the results of the baseline NCCT and,
later on,
he gives a second opinion after getting the CTP results.
Possible replies for first opinion were:
1.
i.v.
tPA—yes
2.
i.v.
tPA—no
3.
Decision delayed after getting CTP data.
Possible replies for second opinion after getting the results of CTP were:
1.
i.v.
tPA—yes
2.
i.v.
tPA—no
3.
Doubt.
In this case,
the decision was postponed after joining the results of CTA (i.e.,
major vessel occlusion,
possibly indicating bridging therapy) along with the possible resolution of clinical conditions contraindicating i.v.
rtPA (i.e., still elevated blood pressure or glucose values).