4.3. Imaging Strategy Efficacy
perfusional abnormalities, spasm, vasospasm, aneurysmal SAH, DCI, infarction
PCT, VASOSPASM, DCI, SECONDARY, INFARCTION
PCT combined with CTA can be used to accurately detect vasospasm [Multiple studies have evaluated PCT for the diagnosis of vasospasm using digital subtraction angiography (DSA) as the reference standard technique. High sensitivity and specificity have been reported for qualitative PCT deficits to detect vasospasm and predict secondary infarction [Currently, transcranial Doppler (TCD) ultrasonography is a widespread noninvasive neuromonitoring technique that allows indirect detection of large vessel narrowing based on quantification of blood flow acceleration. When used as a screening tool in many tertiary centers, TCD ultrasonography suffers from both technical and anatomical limitations [In our study, qualitative PCT was conducted 6 days after aneurysmal SAH. Our results showed that perfusional abnormalities with qualitative PCT occurred in 100% of the patients with severe vasospasm, 53.8% with moderate vasospasm and 5.1% without vasospasm. Current expert opinion favors the use of relative rather than absolute PCT values, given the potential for variability in the absolute quantitation of PCT parameters and the dependence of these values on an appropriate but often arbitrary venous output scaling factor [Our results show that 50% (7/14) of patients with vasospasm in the active stimulation group and 80% (8/10) in the sham group were asymptomatic (All in all, combining PCT with CTA at an early stage appears to be a relevant strategy to detect high-risk vasospasm patient profiles and physicians the opportunity to start more aggressive preventive patient management.However, almost half of the patients with severe vasospasm did not experience DCI. This suggests that, although vasospasm causes a decrease in perfusion in the area behind the spasm, severe vasospasm alone is not sufficient to cause DCI. Most likely, other factors play a role in decreasing cerebral perfusion to the level where DCI occurs. This suggests that the decrease in perfusion caused by vasospasm is not sufficient to cause DCI in all patients, and that radiological vasospasm cannot be directly translated into systematic DCI, but rather indicates a risk. This is consistent with the fact that several treatment methods appear to affect either vasospasm or DCI outcomes, but not both. For example, the nicardipine treatment reduces the incidence of vasospasm but not DCI, and nimodipine, in contrast, reduces the incidence of DCI but not vasospasm [