The role of early perfusion computed tomography in traumatic brain injury

UVOD Izid bolnikov po poškodbi glave (PG) je odvisen od primarnih in sekundarnih poškodb možganovine. Mehanizmi sekundarne poškodbe vključujejo spremembe na ravni možganske prekrvitve ter spremembe prepustnosti krvnomožganske pregrade (KMP). Uveljavljeni modeli za napovedovanje funkcijskega izida bolnikov s PG vključujejo nativno računalniško tomografijo (NCT), ki ima nizko občutljivost za zgodnjo zaznavo sekundarne poškodbe. Po drugi strani perfuzijska CT-preiskava (PCT) omogoča kvantitativno vrednotenje sprememb prekrvitve in prepustnosti KMP. Namen raziskave je bil preveriti, ali se kazalci prekrvitve in prepustnosti KMP razlikujejo med bolniki z ugodnim in neugodnim funkcijskim izidom ter ali ti podatki izboljšajo napovedno vrednost uveljavljenega prognostičnega modela. METODE Vključili smo 50 odraslih bolnikov s hudo in zmerno PG. Ob prvem kontrolnem NCT 12–24 ur po sprejemu smo opravili PCT-preiskavo ter v povirjih velikih možganskih arterij določili vrednosti kazalcev prekrvitve in prepustnosti KMP. Po 6 mesecih smo bolnike ocenili z uporabo Glasgowske lestvice izida (GOS) in razdelili bolnike na tiste z ugodnim (GOS>3) in neugodnim (GOS?3) izidom. Izhodiščnemu prognostičnemu modelu, ki je upošteval starost, motorično komponento GCS, zenične odzive in NCT, smo dodali kazalce možganske prekrvitve in prepustnosti KMP ter izdelane modele primerjali z izračunom prečno preverjenih ploščin (cv-AUC) pod krivuljami ROC. REZULTATI Kazalci možganske prekrvitve in prepustnosti KMP so se med skupinama značilno razlikovali. Model, ki je poleg izhodiščnih spremenljivk upošteval najnižjo izmerjeno vrednost možganskega volumna krvi (CBVmin) in povprečni volumski delež izvenžilnega izvenceličnega prostora (VEmean) je bil značilno boljši od izhodiščnega modela (cv-AUC [95-odstotni interval zaupanja] 0,75 [0,510,84] proti 0,6 [0,370,74]). ZAKLJUČKI Kazalci prekrvitve in prepustnosti KMP, pridobljeni s PCT-preiskavo, se med bolniki z ugodnim in neugodnim funkcijskim izidom po poškodbi glave razlikujejo. Podatki o prekrvitvi možganov in o prepustnosti KMP, ki jih pridobimo s PCT, lahko izboljšajo napovedno vrednost že uveljavljenih prognostičnih modelov pri bolnikih s hudo in zmerno PG.INTRODUCTION Outcome of traumatic brain injury (TBI) patients depends both on the primary and the secondary brain injury. Perfusion disturbances as well as blood-brain barrier permeability (BBBP) alterations constitute the pathophysiological mechanisms of secondary TBI. Currently established prognostic models in TBI include non-contrast computed tomography (NCCT) which is insensitive to early perfusion alterations associated with the secondary TBI. Perfusion CT (PCT) on the other hand offers insight into early perfusion abnormalities and allows the evaluation of BBBP as well. We hypothesized that PCT derived parameters of cerebral perfusion and BBBP differ between the outcome groups and that adding CT perfusion and permeability data to the established outcome predictors improves the performance of the prognostic model. METHODS A prospective cohort study of 50 adult patients with moderate and severe TBI was performed. PCT and routine control NCCT were performed 12-24 hours after admission and regions of interest were drawn on parametric maps in 6 major vascular territories. Glasgow Outcome Scale (GOS) was used 6 months later to categorize patients\u27 functional outcomes to favorable (GOS>3) or unfavorable (GOS⡤3). Core prognostic model consisted of age, motor GCS score (GCSm), pupillary reactivity and NCCT Score. We added perfusion and permeability data as predictors and compared updated models to the core model using cross-validated AUCs. RESULTS Perfusion and BBBP parameters differed significantly between the outcome groups. The prognostic model containing both minimal cerebral blood volume (CBVmin) and the average fraction of cerebral extravascular-extracellular volume (VEmean) in addition to age, GCSm, pupillary reaction, and NCCT score, performed better than the core model (cv-AUC (95% CI) 0.75 (0.51, 0.84) vs. 0.6 (0.37, 0.74)). CONCLUSIONS PCT derived perfusion and permeability parameters differed significantly between the outcome groups. Adding CT perfusion and permeability data to the established outcome predictors may improve the performance of the prognostic model