Temporal and geographical variations in diagnostic imaging in Norway.

BACKGROUND: Unwarranted temporal and geographical variations are acknowledged as a profound problem for equal access and justice in the provision of health services. Even more, they challenge the quality, safety, and efficiency of such services. This is highly relevant for imaging services. OBJECTIVE: To analyse the temporal and geographical variation in the number of diagnostic images in Norway from 2013 to 2021. METHODS: Data on outpatient imaging provided by the Norwegian Health Economics Administration (HELFO) and inpatient data afforded by fourteen hospital trusts and hospitals in Norway. Data include the total number of imaging examinations according to the Norwegian Classification of Radiological Procedures (NCRP). Analyses were performed with descriptive statistics. RESULTS: More than 37 million examinations were performed in Norway during 2013-2021 giving an average of 4.2 million examinations per year. In 2021 there was performed and average of 0.8 examinations per person and 2.2 examinations per person for the age group > 80. There was a 9% increase in the total number of examinations from 2013 to 2015 and a small and stable decrease of 0.5% per year from 2015 to 2021 (with the exception of 2020 due to the pandemic). On average 71% of all examinations were outpatient examinations and 32% were conducted at private imaging centres. There were substantial variations between the health regions, with Region South-East having 53.1% more examinations per inhabitant than Region West. The geographical variation was even more outspoken when comparing catchment areas, where Oslo University Hospital Trust had twice as many examinations per inhabitant than Finnmark Hospital Trust. CONCLUSION: As the population in Norway is homogeneous it is difficult to attribute the variations to socio-economic or demographic factors. Unwarranted and supply-sensitive variations are challenging for healthcare systems where equal access and justice traditionally are core values.

Low-value MRI of the knee in Norway: a register-based study to identify the proportion of potentially low-value MRIs and estimate the related costs.

OBJECTIVES: The objective of this study is to investigate the proportion of potentially low-value knee MRI in Norway and to provide an estimate of the related costs. DESIGN: Register study based on conditional data extraction and analysis of data from Control and Reimbursement of Healthcare Claims registry in Norway. SETTING: MRI in public specialist healthcare with universal health coverage (Norway). PARTICIPANTS: 48 212 MRIs for 41 456 unique patients and 45 946 reimbursement claims. OUTCOME MEASURES: Proportion of MRIs of the knee that (1) did not have a relevant tentative diagnosis prior to the knee MRI, (2) did not have a relevant alternative image of the knee before the MRI or (3) did not have a relevant code from the specialist care within 6 months after the MRI, and those that had combinations of 1, 2 and 3. Estimated costs for those that had combinations of 1, 2 and 3. RESULTS: Very few patients (6.4%) had a relevant diagnosis code or prior imaging examination when having the MRI and only 14.6% got a knee-related diagnosis code from the specialist care within 6 months after the MRI. 21.8% of the patients had knee X-ray, CT or ultrasound within 6 months before the MRI. Between 58% and 85% of patients having knee MRIs in Norway have no relevant examinations or diagnoses six months prior to or after the MRI examination. These examinations are unlikely to benefit patients and they correspond to between 24 108 and 35 416 MRIs at a cost of €6.7-€9.8 million per year. CONCLUSION: A substantial proportion of MRIs of the knee in Norway have no relevant examinations or diagnoses before or after the MRI and are potentially of low value. Reducing low-value MRIs could free resources for high-value imaging, reduce waiting times, improve the quality of care and increase patient safety and professional integrity.

Bioethics: No Method-No Discipline?

This article raises the question of whether bioethics qualifies as a discipline. According to a standard definition of discipline as "a field of study following specific and well-established methodological rules" bioethics is not a specific discipline as there are no explicit "well-established methodological rules." The article investigates whether the methodological rules can be implicit, and whether bioethics can follow specific methodological rules within subdisciplines or for specific tasks. As this does not appear to be the case, the article examines whether bioethics' adherence to specific quality criteria (instead of methodological rules) or pursuing of a common goal can make it qualify as a discipline. Unfortunately, the result is negative. Then, the article scrutinizes whether referring to bioethics institutions and professional qualifications can ascertain bioethics as a discipline. However, this makes the definition of bioethics circular. The article ends by admitting that bioethics can qualify as a discipline according to broader definitions of discipline, for example, as an "area of knowledge, research and education." However, this would reduce bioethics' potential for demarcation and identity-building. Thus, to consolidate the discipline of bioethics and increase its impact, we should explicate and elaborate on its methodology.

Moral obligations towards human persons' wellbeing versus their suffering: An analysis of perspectives of moral philosophy.

What do we owe other persons? Are we as much obliged to promote their wellbeing as we are to reduce their suffering? This question is crucial for a range of social institutions and welfare services, and especially for the health services. To address this question the article investigates prominent positions and arguments in moral philosophy. It finds that while classical utilitarianism claims that there is symmetry in the moral obligation with respect to peoples' wellbeing and their suffering, a wide range of other positions and perspectives argue for an asymmetric relationship with stronger moral obligations towards other persons' suffering than towards their wellbeing. This difference in obligations is supported ontologically by basic differences inherent in wellbeing and suffering and axiologically by a relative (gradual) difference in value. The many well-founded arguments for stronger moral obligations towards other persons' suffering than towards their wellbeing has important implications for health policy; especially for priority setting. Avoiding and reducing suffering should have priority to the promotion and enhancement of wellbeing.

Cost of Low-Value Imaging Worldwide: A Systematic Review.

BACKGROUND AND OBJECTIVE: Imaging with low or no benefit for the patient undermines the quality of care and amounts to vast opportunity costs. More than 3.6 billion imaging examinations are performed annually, and about 20-50% of these are of low value. This study aimed to synthesize knowledge of the costs of low-value imaging worldwide. METHODS: This systematic review was based on the PRISMA statement. The database search was developed in Medline and further adapted to Embase-Ovid, Cochrane Library, and Scopus. Primary empirical studies assessing the costs of low-value diagnostic imaging were included if published between 2012 and March 2022. Studies designed as randomized controlled trials, non-randomized trials, cohort studies, cross-sectional studies, descriptive studies, cost analysis, cost-effectiveness analysis, and mixed-methods studies were eligible. The analysis was descriptive. RESULTS: Of 5,567 records identified, 106 were included. Most of the studies included were conducted in the USA (n = 76), and a hospital or medical center was the most common setting (n = 82). Thirty-eight of the included studies calculated the costs of multiple imaging modalities; in studies with only one imaging modality included, conventional radiography was the most common (n = 32). Aggregated costs for low-value examinations amounts to billions of dollars per year globally. Initiatives to reduce low-value imaging may reduce costs by up to 95% without harming patients. CONCLUSIONS: This study is the first systematic review of the cost of low-value imaging worldwide, documenting a high potential for cost reduction. Given the universal challenges with resource allocation, the large amount used for low-value imaging represents a vast opportunity cost and offers great potential to improve the quality and efficiency of care.

Kairos in diagnostics.

Kairos has been a key concept in medicine for millennia and is frequently understood as "the right time" in relation to treatment. In this study we scrutinize kairos in the context of diagnostics. This has become highly topical as technological developments have caused diagnostics to be performed ever earlier in the disease development. Detecting risk factors, precursors, and predictors of disease (in biomarkers, pre-disease, and pre-pre-disease) has resulted in too early diagnoses, i.e., overdiagnoses. Nonetheless, despite vast advances in science and technology, diagnoses also come too late. Accordingly, timing diagnostics right is crucial. In this article we start with giving a brief overview of the etymology and general use of the concepts of kairos and diagnosis. Then we delimit kairos in diagnostics by analysing "too early" and "too late" diagnosis and by scrutinizing various phases of diagnostics. This leads us to define kairos of diagnostics as the time when there is potential for sufficient information for making a diagnosis that is most helpful for the person. It allows us to conclude that kairos is as important in diagnostics as in therapeutics.

Evaluation of FRESH scores in predicting outcome and quality of life after aneurysmal subarachnoid haemorrhage in a European patient cohort.

BACKGROUND: Despite aneurysmal subarachnoid haemorrhage (aSAH) patients often experiencing physical and mental disabilities impacting their quality of life (QoL), routine assessment of long-term QoL data and predictive tools are limited. This study evaluates the newly developed "functional recovery expected after subarachnoid haemorrhage" (FRESH) scores with long-term outcomes and QoL in European aSAH patients. METHODS: FRESH, FRESH-cog, and FRESH-quol scores were retrospectively obtained from aSAH patients. Patients were contacted, and the modified Rankin Scale (mRS), extended short form-36 (SF-36), and telephone interview for cognitive status (TICS) were collected and performed. The prognostic and empirical outcomes were compared. RESULTS: Out of 374 patients, 171 patients (54.1%) completed the SF-36, and 154 patients completed the TICS. The SF-36 analysis showed that 32.7% had below-average physical component summary (PCS) scores, and 39.8% had below-average mental component summary (MCS) scores. There was no significant correlation between the FRESH score and PCS (p = 0.09736), MCS (p = 0.1796), TICS (p = 0.7484), or mRS 10-82 months (average 46 months) post bleeding (p = 0.024), respectively. There was also no significant correlation found for "FRESH-cog vs. TICS" (p = 0.0311), "FRESH-quol vs. PCS" (p = 0.0204), "FRESH-quol vs. MCS" (p = 0.1361) and "FRESH-quol vs. TICS" (p = 0.1608). CONCLUSIONS: This study found no correlation between FRESH scores and validated QoL tools in a European population of aSAH patients. The study highlights the complexity of reliable long-term QoL prognostication in aSAH patients and emphasises the need for further prospective research to also focus on QoL as an important outcome parameter.

Undermining autonomy and consent: the transformative experience of disease.

Disease radically changes the life of many people and satisfies formal criteria for being a transformative experience. According to the influential philosophy of Paul, transformative experiences undermine traditional criteria for rational decision-making. Thus, the transformative experience of disease can challenge basic principles and rules in medical ethics, such as patient autonomy and informed consent. This article applies Paul's theory of transformative experience and its expansion by Carel and Kidd to investigate the implications for medical ethics. It leads to the very uncomfortable conclusion that disease involves transformative experiences in ways that can reduce people's rational decision-making ability and undermine the basic principle of respect for autonomy and the moral rule of informed consent. While such cases are limited, they are crucial for medical ethics and health policy and deserve more attention and further scrutiny.

Clinical Outcome Prediction of Early Brain Injury in Aneurysmal Subarachnoid Hemorrhage: the SHELTER-Score.

BACKGROUND: Despite intensive research on preventing and treating vasospasm and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage (aSAH), mortality and morbidity rates remain high. Early brain injury (EBI) has emerged as possibly the major significant factor in aSAH pathophysiology, emphasizing the need to investigate EBI-associated clinical events for improved patient management and decision-making. This study aimed to identify early clinical and radiological events within 72 h after aSAH to develop a conclusive predictive EBI score for clinical practice. METHODS: This retrospective analysis included 561 consecutive patients with aSAH admitted to our neurovascular center between 01/2014 and 09/2022. Fourteen potential predictors occurring within the initial 72 h after hemorrhage were analyzed. The modified Rankin Scale (mRS) score at 6 months, discretized to three levels (0-2, favorable; 3-5, poor; 6, dead), was used as the outcome variable. Univariate ordinal regression ranked predictors by significance, and forward selection with McFadden's pseudo-R2 determined the optimal set of predictors for multivariate proportional odds logistic regression. Collinear parameters were excluded, and fivefold cross-validation was used to avoid overfitting. RESULTS: The analysis resulted in the Subarachnoid Hemorrhage Associated Early Brain Injury Outcome Prediction score (SHELTER-score), comprising seven clinical and radiological events: age (0-4 points), World Federation of Neurosurgical Societies (0-2.5 points), cardiopulmonary resuscitation (CPR) (2 points), mydriasis (1-2 points), midline shift (0.5-1 points), early deterioration (1 point), and early ischemic lesion (2 points). McFadden's pseudo-R2 = 0.339, area under the curve for death or disability 0.899 and 0.877 for death. A SHELTER-score below 5 indicated a favorable outcome (mRS 0-2), 5-6.5 predicted a poor outcome (mRS 3-5), and ≥ 7 correlated with death (mRS 6) at 6 months. CONCLUSIONS: The novel SHELTER-score, incorporating seven clinical and radiological features of EBI, demonstrated strong predictive performance in determining clinical outcomes. This scoring system serves as a valuable tool for neurointensivists to identify patients with poor outcomes and guide treatment decisions, reflecting the great impact of EBI on the overall outcome of patients with aSAH.

Revisiting the WFNS Score: Native Computed Tomography Imaging Improves Identification of Patients With "False Poor Grade" Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND AND OBJECTIVES: In patients suffering from aneurysmal subarachnoid hemorrhage (aSAH), the optimal time to determine the World Federation of Neurosurgical Societies (WFNS) score remains controversial because of possible confounding factors. Goals of this study were (1) to analyze the most sensitive timepoint to determine the WFNS score in patients with aSAH and (2) to evaluate the impact of initial native computed tomography (CT) imaging on reducing the mismatch of "false poor grade" patients. METHODS: We retrospectively analyzed daily WFNS scores from admission until day 7 in 535 aSAH patients and evaluated their predictive value for the modified Rankin Scale at discharge and 6 months postbleeding. Patients with an initial WFNS score of IV-V who showed improvement to a WFNS score of I-II within the first 7 days (even short-term) were defined as "false poor grade" patients. We tried to identify the "false poor grade" patients using parameters of the initial native CT imaging. RESULTS: Later determination of the WFNS score (day 1 vs 7; pseudo-R 2 = 0.13 vs 0.21) increasingly improved its predictive value for neurological outcome at discharge ( P < .001). We identified 39 "false poor grade" patients who had significantly better outcomes than "real poor grade" patients (N = 220) (modified Rankin Scale-discharge: 0-2, 56% vs 1%, P < .001; 3-5: 41% vs 56%, P = .12; 6: 3% vs 43%, P < .001). "False poor grade" patients differed significantly in initial CT parameters. A predictive model called "initial CT WFNS" ( ICT WFNS) was developed, incorporating SEBES, Hijdra score, and LeRoux score (sensitivity = 0.95, specificity = 0.84, accuracy = 0.859, F1 = 0.673). ICT WFNS scores of ≤4.6 classified patients as "false poor grade." CONCLUSION: The initial WFNS score may misclassify a subgroup of patients with aSAH as poor grade, which can be avoided by later determination of the WFNS score, at days 3-4 losing its usefulness. Alternatively, the initial WFNS score can be improved in its predictive value, especially in poor-grade patients, using criteria from the initial native CT imaging, such as the Hijdra, LeRoux, and Subarachnoid Hemorrhage Early Brain Edema score, combined in the ICT WFNS score with even higher predictive power.

Variations in wait times for imaging services: a register-based study of self-reported wait times for specific examinations in Norway.

BACKGROUND: While the number of medical images has increased substantially, the demand has outpaced access, resulting in long wait times in many countries. Long wait times are a key problem for patient safety and quality of care as they can result in prolonged suffering, delayed diagnosis and treatment, as well as poorer prognosis and loss of lives. Surprisingly, little is known about wait times for imaging services. OBJECTIVE: Investigate wait times for specific imaging services in Norway and to compare wait times with the total number of examinations and their development over time. METHODS: Data from the wait time registry at the Norwegian Directorate of Health from 2018 to 2021 as well as data on outpatient imaging provided by the Norwegian Health Economics Administration (HELFO) and in-patient data afforded by fourteen hospital trusts and hospitals in Norway were analysed. Data include the total number of imaging examinations according to the Norwegian Classification of Radiological Procedures (NCRP). Analyses were performed with descriptive statistics. RESULTS: Wait times vary through the months of the year. Conventional X-ray (XR) had the shortest wait times (3.0-4.4 weeks), and Magnetic Resonance Imaging (MRI) and ultrasound (US) had the lengthiest (8.7-12.0 and 7.9-11.4 weeks respectively). The wait times were lengthiest during the summer and winter holidays. Variations in wait times were also found for specific examination types between Norway's four public health regions. In addition, there was variation over time within the health regions. The wait times with the private health providers were substantially lower than with the public health providers. From 2018 to 2021, the wait time for MRIs increased by 6.6%, while the number of examinations (per 10,000) increased by 8.6%. Those regions with the highest number of examinations per 1,000 inhabitants per year had the lowest wait times. CONCLUSION: Wait times for diagnostic imaging procedures varied with time, region, and modality in Norway from 2018 to 2021. Long wait times may entail many negative consequences for patients, professionals, and the healthcare system. Reducing long wait times is an obvious way to improve the quality, safety, and efficiency of care.

Does disease incite a stronger moral appeal than health?

Is disease demotion more important than health promotion? The question is crucial for the ethos of medicine and for priority setting in healthcare. When things get tough, where should our attention and resources go: to health or disease? This study investigates two general perspectives on health and disease to address whether there is a stronger moral appeal from people's disease than from their health. While naturalist conceptions of health and disease are mute on moral appeal, normativist conceptions give diverse answers. Classical utilitarianism provides a symmetrical view of health and disease, according to which we have an equally strong moral appeal to further health as we have to reduce disease. Other normativist positions argue that there is an asymmetry between health and disease providing substantial support for a stronger moral appeal from disease than from health. This has a wide range of radical implications, especially within priority setting. In particular, treatment, palliation, and prevention of disease should have priority to the promotion and enhancement of health.

Novel Insights into Pathophysiology of Delayed Cerebral Ischemia: Effects of Current Rescue Therapy on Microvascular Perfusion Heterogeneity.

General microvascular perfusion and its heterogeneity are pathophysiological features of delayed cerebral ischemia (DCI) that are gaining increasing attention. Recently, CT perfusion (CTP) imaging has made it possible to evaluate them radiologically using mean transit time (MTT) and its heterogeneity (measured by cvMTT). This study evaluates the effect of multimodal rescue therapy (intra-arterial nimodipine administration and elevation of blood pressure) on MTT and cvMTT during DCI in aneurysmal subarachnoid haemorrhage (aSAH) patients. A total of seventy-nine aSAH patients who underwent multimodal rescue therapy between May 2012 and December 2019 were retrospectively included in this study. CTP-based perfusion impairment (MTT and cvMTT) on the day of DCI diagnosis was compared with follow-up CTP after initiation of combined multimodal therapy. The mean MTT was significantly reduced in the follow-up CTP compared to the first CTP (3.7 ± 0.7 s vs. 3.3 ± 0.6 s; p < 0.0001). However, no significant reduction of cvMTT was observed (0.16 ± 0.06 vs. 0.15 ± 0.06; p = 0.44). Mean arterial pressure was significantly increased between follow-up and first CTP (98 ± 17 mmHg vs. 104 ± 15 mmHg; p < 0.0001). The combined multimodal rescue therapy was effective in addressing the general microvascular perfusion impairment but did not affect the mechanisms underlying microvascular perfusion heterogeneity. This highlights the need for research into new therapeutic approaches that also target these pathophysiological mechanisms of DCI.

Making and Managing New Biological Entities: conceptual, ontological, epistemological, and ethical aspects.

Novel biotechnologies produce new person-related biological entities, such as cell lines, organoids, and synthetic organisms, that tend to disrupt existing concepts, taxonomies, modes of evidence production, as well as moral norms and values. This raises the question of how we can manage these new person-related biological entities. This article identifies and analyzes key conceptual, ontological, epistemological, and ethical aspects of such entities in order to suggest how to make, manage, and regulate them. It argues that in order to avoid conceptual vagueness and taxonomic confusion, it is important to clarify how person-related biological entities relate to existing concepts and to make new concepts where necessary. Ontologically, we need to determine the thing- and person-likeness of such entities. Epistemically, we must provide measures to verify the characteristics of person-related biological entities and to provide high-quality knowledge of their implications (outcomes). And ethically, we must clarify the moral status, rights, and responsibility for and of the entities, and how they will change our norms and values. Addressing these issues up front may improve our making and managing of person-related biological entities.

Addressing the paradox: Health expansion threatening sustainable healthcare.

We need to address the paradox that health expansion threatens sustainable healthcare as anti-aging drugs are on the trail from trial to the market and come together with health enhancement measures changing demography and the health of populations. This poses global, social, and professional problems, and challenges clinical medicine as well as health policy. To handle the emerging challenges, we need to address four crucial issues: (1) injustice (access), (2) sustainability, (3) basic human rights, and (4) eugenics. To do so we need to differentiate between health improvements and health enhancements and reinforce medicine's strongest moral appeal: to reduce suffering.

Initial Temporal Muscle Thickness and Area: Poor Predictors of Neurological Outcome in Aneurysmal Subarachnoid Hemorrhage in a Central European Patient Cohort.

The temporalis muscle area (TMA) has been proclaimed as a surrogate parameter for estimating skeletal muscle mass. Pilot studies in Asian populations suggested temporal muscle thickness (TMT) and TMA as prognostic factors for neurological outcomes in aneurysmal subarachnoid hemorrhage (aSAH) patients. This study aimed to validate these findings in a larger European patient cohort. We retrospectively analyzed age, sex, aneurysm location, treatment, World Federation of Neurosurgical Societies (WFNS) grade, Fisher score, and modified Rankin Score (mRS) at six months in patients with aSAH. TMT and TMA measurements were obtained from initial native CT scans. Logistic regression with the dichotomized six-month mRS as the outcome incorporating TMT, weighted average of TMT, or TMA as predictors was performed. Of the included 478 patients, 66% were female, the mean age was 56, and 48% of patients had an mRS of three to six after six months. The mean TMT at the level of the Sylvian fissure was 5.9 (±1.7) mm in males and 4.8 (±1.8) mm in females. The mean TMA was 234.5 (±107.9) mm2 in females and 380 (±134.1) mm2 in males. WFNS grade (p < 0.001), Fisher score (p < 0.001), and age (p < 0.05) correlated significantly with the mRS after six months. No correlation was found between mRS after six months and the TMT at the Sylvian fissure (p = 0.3), the weighted average of TMT (p = 0.1), or the TMA (p = 0.1). In this central European patient cohort of 478 individuals, no significant associations were found between TMT/TMA and neurological outcomes following aSAH. Further prospective studies in diverse patient populations are necessary to determine the prognostic value of TMA and TMT in aSAH patients.

Long term outcomes and causal modelling of compulsory inpatient and outpatient mental health care using Norwegian registry data: Protocol for a controversies in psychiatry research project.

OBJECTIVES: Compulsory mental health care includes compulsory hospitalisation and outpatient commitment with medication treatment without consent. Uncertain evidence of the effects of compulsory care contributes to large geographical variations and a controversy on its use. Some argue that compulsion can rarely be justified and should be reduced to an absolute minimum, while others claim compulsion can more frequently be justified. The limited evidence base has contributed to variations in care that raise issues about the quality/appropriateness of care as well as ethical concerns. To address the question whether compulsory mental health care results in superior, worse or equivalent outcomes for patients, this project will utilise registry-based longitudinal data to examine the effect of compulsory inpatient and outpatient care on multiple outcomes, including suicide and overall mortality; emergency care/injuries; crime and victimisation; and participation in the labour force and welfare dependency. METHODS: By using the natural variation in health providers' preference for compulsory care as a source of quasi-randomisation we will estimate causal effects of compulsory care on short- and long-term trajectories. CONCLUSIONS: This project will provide valuable insights for service providers and policy makers in facilitating high quality clinical care pathways for a high risk population group.

Evaluation of MTT Heterogeneity of Perfusion CT Imaging in the Early Brain Injury Phase: An Insight into aSAH Pathopysiology.

The concept of early brain injury (EBI) is based on the assumption of a global reduction in brain perfusion following aneurysmal subarachnoid hemorrhage (aSAH). However, the heterogeneity of computed tomography perfusion (CTP) imaging in EBI has not yet been investigated. In contrast, increased mean transit time (MTT) heterogeneity, a possible marker of microvascular perfusion heterogeneity, in the delayed cerebral ischemia (DCI) phase has recently been associated with a poor neurological outcome after aSAH. Therefore, in this study, we investigated whether the heterogeneity of early CTP imaging in the EBI phase is an independent predictor of the neurological outcome after aSAH. We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation (cvMTT) in early CTP scans (within 24 h after ictus) of 124 aSAH patients. Both linear and logistic regression were used to model the mRS outcome, which were treated as numerical and dichotomized values, respectively. Linear regression was used to investigate the linear dependency between the variables. No significant difference in cvMTT between the patients with and those without EVD could be observed (p = 0.69). We found no correlation between cvMTT in early CTP imaging and initial modified Fisher (p = 0.07) and WFNS grades (p = 0.23). The cvMTT in early perfusion imaging did not correlate significantly with the 6-month mRS for the entire study population (p = 0.15) or for any of the subgroups (without EVD: p = 0.21; with EVD: p = 0.3). In conclusion, microvascular perfusion heterogeneity, assessed by the heterogeneity of MTT in early CTP imaging, does not appear to be an independent predictor of the neurological outcome 6 months after aSAH.