Incidental Findings in Head and Brain MRI of Military Pilots and Applicants: Consequences for Medical Flight Fitness.

INTRODUCTION: With improved imaging technology, the number of incidental findings detected in cerebral MRI is increasing. This is a challenge that the German Air Force has to deal with in the context of standardized MRI examinations of young pilot candidates and pilots.METHODS: The German Air Force Centre of Aerospace Medicine hosted a 2-d conference to develop recommendations and procedures for the handling of some of the most frequently encountered cerebral incidental findings.RESULTS: Radiological MRI findings from a total of 2724 routine examinations of the skull of pilots and pilot applicants (26.8 ± 10.6 yr old; range from 16 to 62; over 80% range from 17 to 33; 96% men) revealed that in 28.1% of the examinations, one or more incidental findings were discovered. For seven of the following categories of incidental findings, decision guidelines could be established: white matter hyperintensities (N = 393; prevalence 14.4%; 95% CI 13.11-15.75), pinealis cysts (317; 11.6%; 10.43-12.84), developmental venous anomalies (64; 2.3%; 1.78-2.92), cavernomas (15; 0.6%; 0.27-0.83), aneurysms (14; 0.5%; 0.25-0.78), cholesterol granulomas (22; 0.8%; 0.47-1.14), and heterotopias of the gray matter (6; 0.2%; 0.04-0.4).CONCLUSION: Considering pilots health and aviation safety, a waiver decision is often possible after thorough discussion, depending on the specific criteria of the incidental finding and of the type of license.Kühn S, Sönksen S-E, Noble H-J, Knopf H, Frischmuth J, Waldeck S, Müller-Forell W, Weber F, Bressem L. Incidental findings in head and brain MRI of military pilots and applicants: consequences for medical flight fitness. Aerosp Med Hum Perform. 2022; 93(5):450-457.

Binostril versus mononostril approaches in endoscopic transsphenoidal pituitary surgery: clinical evaluation and cadaver study.

OBJECTIVE Over the past 2 decades, endoscopy has become an integral part of the surgical repertoire for skull base procedures. The present clinical evaluation and cadaver study compare binostril and mononostril endoscopic transnasal approaches and the surgical techniques involved. METHODS Forty patients with pituitary adenomas were treated with either binostril or mononostril endoscopic surgery. Neurosurgical, endocrinological, ophthalmological, and neuroradiological examinations were performed. Ten cadaver specimens were prepared, and surgical aspects of the preparation and neuroradiological examination were documented. RESULTS In the clinical evaluation, 0° optics were optimal in the nasal and sphenoidal phase of surgery for both techniques. For detection of tumor remnants, 30° optics were superior. The binostril approach was significantly more time consuming than the mononostril technique. The nasal retractor limited maneuverability of instruments during mononostril approaches in 5 of 20 patients. Endocrinological pituitary function, control of excessive hormone secretion, ophthalmological outcome, residual tumor, and rates of adverse events, such as CSF leaks and diabetes insipidus, were similar in both groups. In the cadaver study, there was no significant difference in the time required for dissection via the binostril or mononostril technique. The panoramic view was superior in the binostril group; this was due to the possibility of wider opening of the sella in the craniocaudal and horizontal directions, but the need for removal of more of the nasal septum was disadvantageous. CONCLUSIONS Because of maneuverability of instruments and a wider view in the sphenoid sinus, the binostril technique is superior for resection of large tumors with parasellar and suprasellar expansion and tumors requiring extended approaches. The mononostril technique is preferable for tumors with limited extension in the intra- and suprasellar area.

Flow cytometric analysis of T cell/monocyte ratio in clinically isolated syndrome identifies patients at risk of rapid disease progression.

BACKGROUND: Multiple sclerosis is a chronic inflammatory central nervous system disease diagnosed by clinical presentation and characteristic magnetic resonance imaging findings. The role of cerebrospinal fluid (CSF) analysis has been emphasized in particular in the context of differential diagnosis in patients with a first episode suggestive of multiple sclerosis. OBJECTIVE: We investigated here the potential additional value of analysis of CSF cellularity by fluorescence activated cell sorting (FACS) in the setting of a routine diagnostic work-up in our inpatient clinic. METHODS: CSF cells from back-up samples from patients with suspected chronic inflammatory central nervous system disorder were analyzed by FACS and correlated with clinical data, magnetic resonance imaging findings and oligoclonal band status. RESULTS: We found distinct changes of T cell/monocyte (CD4/CD14) and B cell/monocyte (CD20/CD14) ratios between clinically isolated syndrome (CIS)/multiple sclerosis and other neurologic diseases or other inflammatory neurologic diseases. In particular, patients with a rapid transition from CIS to multiple sclerosis had an elevated CD4/CD14 ratio. A subgroup analysis showed diagnostic value of CD4/CD8 ratio in the differential diagnosis of CIS/multiple sclerosis to neurosarcoidosis. CONCLUSION: The diagnostic and prognostic accuracy of autoimmune neuroinflammatory diseases can be improved by FACS analysis of CSF cells.

Vestibular thalamus: Two distinct graviceptive pathways.

OBJECTIVE: To determine whether there are distinct thalamic regions statistically associated with either contraversive or ipsiversive disturbance of verticality perception measured by subjective visual vertical (SVV). METHODS: We used modern statistical lesion behavior mapping on a sample of 37 stroke patients with isolated thalamic lesions to clarify which thalamic regions are involved in graviceptive otolith processing and whether there are distinct regions associated with contraversive or ipsiversive SVV deviation. RESULTS: We found 2 distinct systems of graviceptive processing within the thalamus. Contraversive tilt of SVV was associated with lesions to the nuclei dorsomedialis, intralamellaris, centrales thalami, posterior thalami, ventrooralis internus, ventrointermedii, ventrocaudales and superior parts of the nuclei parafascicularis thalami. The regions associated with ipsiversive tilt of SVV were located in more inferior regions, involving structures such as the nuclei endymalis thalami, inferior parts of the nuclei parafascicularis thalami, and also small parts of the junction zone of the nuclei ruber tegmenti and brachium conjunctivum. CONCLUSIONS: Our data indicate that there are 2 anatomically distinct graviceptive signal processing mechanisms within the vestibular network in humans that lead, when damaged, to a vestibular tone imbalance either to the contraversive or to the ipsiversive side.

Evaluation of MRI and cannabinoid type 1 receptor PET templates constructed using DARTEL for spatial normalization of rat brains.

PURPOSE: Image registration is one prerequisite for the analysis of brain regions in magnetic-resonance-imaging (MRI) or positron-emission-tomography (PET) studies. Diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) is a nonlinear, diffeomorphic algorithm for image registration and construction of image templates. The goal of this small animal study was (1) the evaluation of a MRI and calculation of several cannabinoid type 1 (CB1) receptor PET templates constructed using DARTEL and (2) the analysis of the image registration accuracy of MR and PET images to their DARTEL templates with reference to analytical and iterative PET reconstruction algorithms. METHODS: Five male Sprague Dawley rats were investigated for template construction using MRI and [(18)F]MK-9470 PET for CB1 receptor representation. PET images were reconstructed using the algorithms filtered back-projection, ordered subset expectation maximization in 2D, and maximum a posteriori in 3D. Landmarks were defined on each MR image, and templates were constructed under different settings, i.e., based on different tissue class images [gray matter (GM), white matter (WM), and GM + WM] and regularization forms ("linear elastic energy," "membrane energy," and "bending energy"). Registration accuracy for MRI and PET templates was evaluated by means of the distance between landmark coordinates. RESULTS: The best MRI template was constructed based on gray and white matter images and the regularization form linear elastic energy. In this case, most distances between landmark coordinates were <1 mm. Accordingly, MRI-based spatial normalization was most accurate, but results of the PET-based spatial normalization were quite comparable. CONCLUSIONS: Image registration using DARTEL provides a standardized and automatic framework for small animal brain data analysis. The authors were able to show that this method works with high reliability and validity. Using DARTEL templates together with nonlinear registration algorithms allows for accurate spatial normalization of combined MRI/PET or PET-only studies.

Mechanical recanalization in basilar artery occlusion: the ENDOSTROKE study.

OBJECTIVE: A study was undertaken to evaluate clinical and procedural factors associated with outcome and recanalization in endovascular stroke treatment (EVT) of basilar artery (BA) occlusion. METHODS: ENDOSTROKE is an investigator-initiated multicenter registry for patients undergoing EVT. This analysis includes 148 consecutive patients with BA occlusion, with 59% having received intravenous thrombolysis prior to EVT. Recanalization (defined as Thrombolysis in Cerebral Infarction [TICI] score 2b-3) and collateral status (using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology collateral grading system) were assessed by a blinded core laboratory. Good (moderate) outcome was defined as a modified Rankin Scale score of 0 to 2 (0-3) assessed after at least 3 months (median time to follow-up = 120 days). RESULTS: Thirty-four percent had good and 42% had moderate clinical outcome; mortality was 35%. TICI 2b-3 recanalization was achieved by 79%. Age, hypertension, National Institutes of Health Stroke Scale scores, collateral status, and the use of magnetic resonance imaging prior to EVT predicted clinical outcome, the latter 3 remaining independent predictors in multivariate analysis. Independent predictors of recanalization were better collateral status and the use of a stent retriever. However, recanalization did not significantly predict clinical outcome. INTERPRETATION: Beside initial stroke severity, the collateral status predicts clinical outcome and recanalization in BA occlusion. Our data suggest that the use of a stent retriever is associated with high recanalization rates, but recanalization on its own does not predict outcome. The role of other modifiable factors, including the choice of pretreatment imaging modality and time issues, warrants further investigation.

Anosognosia for hemiparesis after left-sided stroke.

In patients with left-sided lesions, anosognosia for hemiparesis (AHP) seems to be a rare phenomenon. It has been discussed whether this rareness might be due to an inevitable bias due to language dysfunction and whether the left hemisphere's role for our self-awareness of motor actions thus is underestimated. By applying functional magnetic resonance imaging (fMRI) we examined whether patients with AHP following a left hemisphere stroke show a regular, left-sided or a reversed, right-sided lateralization of language functions. Only the former observation would argue for an original role of the left hemisphere in self-awareness about limb function. In a consecutive series of 44 acute left-sided stroke patients, only one patient (=2%) was identified showing AHP. In this case, we could verify by using fMRI that lateralization of AHP and spatial neglect on the one hand and of language functions on the other hand were reversed. The present single case observation thus argues against an original role of the left hemisphere in self-awareness about limb function. We discuss the data in the context of previous observations in the literature.

How to treat tumefactive demyelinating disease?

Glioma-like inflammatory demyelinating lesions can be found in patients with pre-diagnosed multiple sclerosis, but they have also been described as an isolated disease entity. The initial diagnostic work-up usually includes a biopsy for histopathological analysis. However, even after unambiguous histopathologic classification, tumefactive lesions pose a therapeutic challenge. Until now, there have been no guidelines on how to treat patients with these rare and extreme lesion phenotypes. Here we report a patient with a relapsing unifocal tumefactive demyelinating lesion. The patient initially showed a good response to steroid treatment, with full clinical recovery. However, after relapse of the same lesion, recovery was incomplete. Although immunosuppression was initiated, the patient presented with subsequent further deterioration. Only maximal escalation of immunosuppression was able to stop the inflammatory activity. Due to the length of time of the step-wise escalation treatment however, the lengthy lesion activity led to irreversible tissue destruction and residual non-remitting disability. Early aggressive treatment with an induction therapy regimen might be more appropriate for these rare and often strongly disabling lesion subtypes.

MRI and neurophysiology in vestibular paroxysmia: contradiction and correlation.

BACKGROUND: Vestibular paroxysmia (VP) is defined as neurovascular compression (NVC) syndrome of the eighth cranial nerve (N.VIII). The aim was to assess the sensitivity and specificity of MRI and the significance of audiovestibular testing in the diagnosis of VP. METHODS: 20 VP patients and, for control, 20 subjects with trigeminal neuralgia (TN) were included and underwent MRI (constructive interference in steady-state, time-of-flight MR angiography) for detection of a NVC between N.VIII and vessels. All VP patients received detailed audiovestibular testing. RESULTS: A NVC of N.VIII could be detected in all VP patients rendering a sensitivity of 100% and a specificity of 65% for the diagnosis of VP by MRI. Distance between brain stem and compressing vessels varied between 0.0 and 10.2 mm. In 15 cases, the compressing vessel was the anterior inferior cerebellar artery (75%, AICA), the posterior inferior cerebellar artery in one (5%, posterior inferior cerebellar artery (PICA)), a vein in two (10%) and the vertebral artery (10%, VA) in another two cases. Audiovestibular testing revealed normal results in five patients (25%), a clear unilateral loss of audiovestibular function in nine patients (45%) and audiovestibular results with coinstantaneous signs of reduced and increased function within the same nerve in six patients (30%). From the 20 TN patients 7, (35%) showed a NVC of the N.VIII (5 AICA, 1 PICA, 1 vein). CONCLUSIONS: Only the combination of clinical examination, neurophysiological and imaging techniques is capable of (1) defining the affected side of a NVC and to (2) differentiate between a deficit syndrome and increased excitability in VP.

Insular strokes cause no vestibular deficits.

BACKGROUND AND PURPOSE: In previous imaging studies, the posterior insular cortex (IC) was identified as an essential part for vestibular otolith perception and considered as a core region of a human vestibular cortical network. However, it is still unknown whether lesions exclusively restricted to the posterior IC suffice to provoke signs of vestibular otolith dysfunction. Thus, present data aimed to test whether patients with lesions restricted to the IC showed vestibular otolith dysfunction. METHODS: We studied 10 acute unilateral stroke patients with lesions restricted to the IC which were tested for signs of vestibular otolith dysfunction, such as tilts of subjective visual vertical, out of 475 stroke patients. RESULTS: None of the patients was with stroke exclusively affecting the IC-specified vertigo as a symptom. In addition, neither showed a deficit in the perception of verticality (subjective visual vertical tilts) nor showed any further vestibular otolith deficits, such as ocular torsion or skew deviation. CONCLUSIONS: It seems that lesions of the posterior IC might have to be combined with lesions of adjacent regions of the cortical and subcortical vestibular network to cause vestibular otolith deficits.

Computed tomographic angiography as a useful adjunct in the diagnosis of brain death.

BACKGROUND: Because of its widespread accessibly, computed tomographic angiography (CT-A) is a promising technique in the detection of intracranial circulatory arrest in brain death (BD). Several studies assessed this tool, but neither have standardized evaluation parameters been developed nor has information about specificity become available. METHODS: We conducted a prospective study between January 2008 and April 2012. Thirty patients were admitted to our University Hospital (16 men and 14 women; age, 18-88 years) and underwent CT-A scanning at two occasions: immediately after the first signs of loss of brain stem reflexes and after definitive determination of brain. The results of CT-A were compared with transcranial Doppler ultrasonography and electroencephalogram. RESULTS: In 3 of 30 patients, we observed a termination of contrast flow at the level of the skull base and foramen magnum in arterial scanning series before the clinical determination of BD. After the clinical determination of BD, the opacification of all vascular territories in arterial phase scanning was found in one case, but venous phase scanning revealed no blood return in internal cerebral veins. In all other cases, contrast filling ceased at level of skull base or below. The specificity of CT-A in the detection of intracranial circulatory arrest was 90%, and sensitivity was 97%. CONCLUSION: CT-A is reliable and appropriate technical investigation to detect intracranial circulatory arrest in BD. The evaluation of contrast enhancement in arterial phase scanning seems to be more reliable than that in venous phase. An international consensus about a uniformly applied CT-A protocol for the evaluation of BD should be established.

Development of a Scoring System to Evaluate the Severity of Craniocervical Spinal Cord Compression in Patients with Mucopolysaccharidosis IVA (Morquio A Syndrome).

BACKGROUND: As spinal cord compression at the craniocervical junction (CCJ) is a life-threatening manifestation in patients with mucopolysaccharidosis (MPS) IVA, surgical decompression should be performed before damage becomes irreversible. We evaluated the diagnostic value of several examinations for determining the need for decompression surgery. METHODS: We retrospectively analysed results of clinical neurological examination, somatosensory evoked potential (SEP) and magnetic resonance imaging (MRI) in 28 MPS IVA patients. A scoring system - based on the severity of findings - was used to compare results of patients with and without indication for decompression surgery. Individual test scores and two composite scores were evaluated for their potential to assess severity of CCJ impairment. RESULTS: Sixteen patients had an indication for surgery; 12 of them had undergone surgery. Twelve patients had no indication for surgery; none had received surgery. Neurological (P = 0.004), MRI (P < 0.001) and atlantoaxial subluxation (P = 0.006) scores, but not SEP and odontoid hypoplasia scores, differed significantly between patients with and without surgical indication. Both the abbreviated CCJ score, i.e. sum of neurological and MRI scores, and the extended CCJ score, i.e. sum of abbreviated CCJ and atlantoaxial subluxation score, discriminated between patients with and without surgical indication (abbreviated: 0-2 points vs 2-5 points, P < 0.001; extended: 0-3 points vs 3-7 points; P < 0.001). Although CCJ instability plays a major role in cervical cord pathology, decompression surgery without occipito-cervical stabilisation may yield good postoperative results. CONCLUSIONS: The abbreviated and extended CCJ scores are objective, transparent and reproducible tools for assessing the CCJ pathology and the need for surgery.

A boy with homozygous microdeletion of NEUROG1 presents with a congenital cranial dysinnervation disorder [Moebius syndrome variant].

BACKGROUND: We report on a 6-year-old Turkish boy with profound sensorineural deafness, balance disorder, severe disorder of oral motor function, and mild developmental delay. Further findings included scaphocephaly, plagiocephaly, long palpebral fissures, high narrow palate, low-set posteriorly rotated ears, torticollis, hypoplastic genitalia and faulty foot posture. Parents were consanguineous. METHODS AND RESULTS: Computed tomography and magnetic resonance imaging showed bilateral single widened cochlear turn, narrowing of the internal auditory canal, and bilateral truncation of the vestibulo-cochlear nerve. Microarray analysis and next generation sequencing showed a homozygous deletion of chromosome 5q31.1 spanning 115.3 kb and including three genes: NEUROG1 (encoding neurogenin 1), DCNP1 (dendritic cell nuclear protein 1, C5ORF20) and TIFAB (TIFA-related protein). The inability to chew and swallow, deafness and balance disorder represented congenital palsies of cranial nerves V (trigeminal nerve) and VIII (vestibulo-cochlear nerve) and thus a congenital cranial dysinnervation disorder. CONCLUSIONS: Based on reported phenotypes of neurog1 null mutant mice and other vertebrates, we strongly propose NEUROG1 as the causative gene in this boy. The human NEUROG1 resides within the DFNB60 locus for non-syndromic autosomal recessive deafness on chromosome 5q22-q31, but linkage data have excluded it from being causative in the DFNB60 patients. Given its large size (35 Mb, >100 genes), the 5q22-q31 area could harbor more than one deafness gene. We propose NEUROG1 as a new gene for syndromic autosomal recessive hearing loss and congenital cranial dysinnervation disorder including cranial nerves V and VIII.

Craniocervical decompression in patients with mucopolysaccharidosis VI: development of a scoring system to determine indication and outcome of surgery.

OBJECTIVE: To analyse diagnostic value of somato-sensory evoked potentials (SEP), magnetic resonance imaging (MRI), and clinical neurological examination in the decision for decompression surgery in mucopolysaccharidosis (MPS) VI patients with craniocervical cord compression (CCJ). METHODS: We retrospectively analysed neurological examination, SEP of the median nerve and MRI outcomes from 31 MPS VI patients. Individual scores for each test (based on severity of findings) and a sum of scores of all three procedures (CCJ score) were evaluated for their potential to measure the need for and improvement after surgery. Differences between rapidly and slowly progressive patients were also evaluated. RESULTS: Fourteen patients (45 %) aged 4-34 years underwent decompression surgery. Median age at first operation was lower in rapidly than in slowly progressive patients (12 vs. 24 years; P = 0.008). Neurological and SEP findings but not MRI results differed significantly between non-operated and operated patients (P < 0.001, P = 0.003 and P = 0.08, respectively). A significant relationship was found between MRI and clinical neurological examination (P < 0.001) and between SEP and clinical neurological examination (P = 0.01) but not between MRI and SEP (P = 0.06). The CCJ score discriminated between operated and non-operated patients (4-9 points vs. 0-3 points; P < 0.001) and decreased in 61.5 % of patients after surgery. CONCLUSIONS: CCJ is common in rapidly and slowly progressive MPS VI patients. The CCJ score is an objective and transparent tool for assessing pathology of the CCJ, the need for surgery, and improvement after surgery.

Posterior insular cortex - a site of vestibular-somatosensory interaction?

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact.

Technical aids in the diagnosis of brain death: a comparison of SEP, AEP, EEG, TCD and CT angiography.

BACKGROUND: The use of technical aids to confirm brain death is a controversial matter. Angiography with the intra-arterial administration of contrast medium is the international gold standard, but it is not allowed in Germany except in cases where it provides a potential mode of treatment. The currently approved tests in Germany are recordings of somatosensory evoked potentials (SSEP), brain perfusion scintigraphy, transcranial Doppler ultrasonography (TCD), and electroencephalography (EEG). CT angiography (CTA), a promising new alternative, is being increasingly used as well. METHODS: In a prospective, single-center study that was carried out from 2008 to 2011, 71 consecutive patients in whom brain death was diagnosed on clinical grounds underwent recording of auditory evoked potentials (AEP) and SSEP as well as EEG, TCD and CTA. RESULTS: The validity of CTA for the confirmation of brain death was 94%; the validity of the other tests was: 94% for EEG, 92% for TCD, 82% for SSEP, and 2% for AEP. In 61 of the 71 patients (86%), the EEG, TCD and CTA findings all accorded with the clinical diagnosis. The diagnosis of brain death was established beyond doubt in all patients. CONCLUSION: In this study, the technical aids yielded discordant results in 14% of cases, necessitating interpretation by an expert examiner. The perfusion tests, in particular, can give false-positive results in patients with large cranial defects, skull fractures, or cerebrospinal fluid drainage. In such cases, electrophysiologic tests or a repeated clinical examination should be performed instead. CTA is a promising, highly reliable new method for demonstrating absent intracranial blood flow. In our view, it should be incorporated into the German guidelines for the diagnosis of brain death.

Neuroimaging of Graves' orbitopathy.

Neuroimaging of Graves' orbitopathy (GO) plays an important role in the differential diagnosis and interdisciplinary management of patients with GO. Orbital imaging is required in unclear or asymmetric proptosis, in suspected optic neuropathy and prior to decompression surgery. Especially computed tomography and magnetic resonance (MR) imaging show the actual objective morphological findings, quantitative MR imaging giving additional information concerning the acuteness or chronicity of the disease. Major morphological diagnostic criteria include a spindle like spreading of the rectus muscles without involvement of the tendon, a compression of the optic nerve in the orbital apex (crowded orbital apex syndrome) and the absence of any space occupying intraorbital process. A longer lasting course of the disease may lead to a corresponding impression of the lamina papyracae, the normally parallel configured medial wall of the orbit, similar to a spontaneous decompression.

CT angiography as a confirmatory test in brain death.

OBJECTIVE: From recent studies, it remains unclear whether CT angiography could be an alternative to other established ancillary tests for the diagnosis of brain death. We examined intracranial contrast enhancement in CT angiography after clinically established brain death and compared the results with EEG and TCD findings. MATERIALS AND METHODS: Prospective study between April 2008 and January 2010. EEG, TCD and CT angiography were performed in 40 patients aged between 18 and 88 years (mean 56 years) who fulfilled the clinical criteria of brain death. RESULTS: In all cases, the common carotid artery, cervical internal carotid artery, cervical vertebral artery and superficial temporal artery opacified in an arterial CT angiography series. 37 out of 40 cases demonstrated no opacification of both MCA-M4, ACA-A3, PCA-P2 segments, and BA. CONCLUSION: CT angiography is a promising method of evaluating intracranial circulatory arrest in brain death with a high spatial and temporal resolution, superior to all other established technical procedures. The examination is easily accessible in most hospitals, operator independent, minimally invasive and inexpensive. Therefore, CT angiography has the potential to enlarge the existing armamentarium of confirmatory brain death tests.