Implementation of Computed Tomography Angiography (CTA) and Computed Tomography Perfusion (CTP) in Polish Guidelines for Determination of Cerebral Circulatory Arrest (CCA) during Brain Death/Death by Neurological Criteria (BD/DNC) Diagnosis Procedure

Abstract

Background: Brain death/death by neurologic criteria (BD/DNC) guidelines are routinely analyzed, compared and updated in the majority of countries and are later implemented as national criteria. At the same time, extensive works have been conducted in order to unify clinical procedures and to validate and implement new technologies into a panel of ancillary tests. Recently evaluated computed tomography angiography and computed tomography perfusion (CTA/CTP) seem to be superior to traditionally used digital subtraction angiography (DSA), transcranial Doppler (TCD) and cerebral perfusion scintigraphy for diagnosis of cerebral circulatory arrest (CCA). In this narrative review, we would like to demonstrate scientific evidence supporting the implementation of CTA/CTP in Polish guidelines for BD/DNC diagnosis. Research and implementation process: In the first of our base studies concerning the potential usefulness of CTA/CTP for the confirmation of CCA during BD/DNC diagnosis procedures, we showed a sensitivity of 96.3% of CTA in a group of 82 patients. CTA was validated against DSA in this report. In the second study, CTA showed a sensitivity of 86% and CTP showed a sensitivity of 100% in a group of 50 patients. In this study, CTA and CTP were validated against clinical diagnosis of BD/DNC supported by TCD. Additionally, we propose our CCA criteria for CTP test, which are based on ascertainment of cerebral blood flow (CBF) < 10 mL/100 g/min and cerebral blood volume < 1 mL/100 g in regions of interest (ROIs) localized in all brain regions. Based on our research results, CTA/CTP methods were implemented in Polish BD/DNC criteria. To our knowledge, CTP was implemented for the first time in national guidelines. Conclusions: CTA and CTP-derived CTA might be in future the tests of choice for CCA diagnosis, proper and/or Doppler pretest might significantly increase sensitivity of CTA in CCA diagnosis procedures. Whole brain CTP might be decisive in some cases of inconclusive CTA. Implementation of CTA/CTP in the Polish BD/DNC diagnosis guidelines does not show any major obstacles. We believe that in next edition of “The World Brain Death Project” CTA and CTP will be recommended as ancillary tests of choice for CCA confirmation during BD/DNC diagnosis procedures.

Brain death/death by neurologic criteria determination: an update

“…If a portion of the clinical examination or the apnea test cannot be completed, unresolvable confounding conditions are present, or uncertainty regarding interpretation or if possible spinally mediated movements exist, ancillary testing is needed [1 ▪▪ ,17]. There are advantages and disadvantages to all ancillary tests [30]. The following ancillary tests are used as additional tests to determine brain death/DNC: 1neurophysiological function tests: electroencephalography and evoked potentials and tests to assess for presence or absence of intracranial blood flow such as 4-vessel conventional cerebral angiography, computed tomographic angiography [29,30], radionuclide studies using diffusible radiopharmaceuticals [1 ▪▪ ], and transcranial Doppler ultrasonography.…”

“…There are advantages and disadvantages to all ancillary tests [30]. The following ancillary tests are used as additional tests to determine brain death/DNC: 1neurophysiological function tests: electroencephalography and evoked potentials and tests to assess for presence or absence of intracranial blood flow such as 4-vessel conventional cerebral angiography, computed tomographic angiography [29,30], radionuclide studies using diffusible radiopharmaceuticals [1 ▪▪ ], and transcranial Doppler ultrasonography. There is discussion if MRA can be used as an ancillary test in brain death/DNC determination, and the results of further research into the sensitivity and specificity are awaited.…”

Computed Tomography Angiography (CTA) in Selected Scenarios with Risk of Possible False-Positive or False-Negative Conclusions in Diagnosing Brain Death

“…In other words, 100% specificity should be the goal in this particular clinical situation. According to the statements of the “World Brain Death Project” [ 1 ] concerning blood perfusion tests, the sensitivity varies mainly in a range of 52–100% while specificity is close to 100%, but there is the remark that specificity is assumed on the basis of experimental data and should be therefore interpreted with caution given the limitation of studies that reported only on clinically confirmed BD/DNC [ 29 ].…”

“…New-generation multi-slice CT scanners are suitable to visualize vasculature and perfusion of the whole brain with a single intravenous injection of iodinated contrast medium to verify cerebral perfusion stop. National guidelines introduced CTA in several countries e.g., Austria, Canada, Croatia, France, Germany, Netherlands, Poland or Switzerland [ 26 , 29 , 39 , 40 ].…”

“…In Germany [ 28 ], evidence of irreversibility of brain function loss can be ancillary based on an isoelectric EEG or extinction of intracerebral components of brainstem auditory evoked potentials (BAEP) or early cortical (N20 component) and high cervical somatosensory evoked potentials (SEP) or detection of cerebral circulatory arrest by TCD/CCDS, cerebral perfusion scintigraphy or CT angiography. For an overview of ancillary examinations see Table 1 , which is based on the three official recommendations described [ 26 , 27 , 28 ] and articles by various authors [ 15 , 21 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. These three examples show that several supplementary tests are equally allowed in the national recommendations, which may lead to misinterpretations of relevance between the different tests (especially, if the supplemental guidance on the limitations and scope of specific testing procedures in the respective official guidelines is over-read in detail and/or not interpreted correctly by users).…”