Genes impacting the bioaccumulation of perfluoroalkyl and polyfluoroalkyl substances (PFASs)and their neurotoxic effects on the brain and behavior remain unclear. Here,we examined genome-wide associations with serum accumulation of 13 PFASs in 6,823 Chinese adults. We revealed that perfluoroheptanoic acid (PFHpA) accumulation was associated with genetic variants at two loci (3q29: P = 5.20 ×10-19; 6p22.2: P = 3.69 ×10-23), mapping to 56 genes.Blood expression of 27 of these genes was associated with PFHpA accumulation in 573 subsamples. Eight genes showed potential causal effects on PFHpA accumulation,functionally linked to innate immunity (TRIM38, ZDHHC19, MUC20)and organic solute transport (SLC51A and SLC17A3). We assessed the impact of PFASs on cortical thickness and surface area, white matter fractional anisotropy and mean diffusivity,along with 25 behavioral phenotypes. We identified that seven PFASs were correlated with reduced cortical morphology, primarily in the prefrontal cortex. We also found a statistical causal effect of PFHpA accumulation on the surface area in the right frontomarginal cortex, which mediated the effect of PFHpA on anxiety. These findings indicate that serum PFHpA accumulation may be regulated by genes related to innate immunity and solute transport, heightening anxiety by impairing the prefrontal cortex.

BACKGROUND:As an extension of diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI) quantifies non-Gaussian water diffusion and has been applied to explore brain disorders. However, the genetic architecture of brain DKI phenotypes remains unknown. METHODS:Here, we estimated heritability and conducted genome-wide association studies (GWASs) for 804 DKI phenotypes across 188 brain structures in 4183 participants. To determine whether DKI-GWASs provides genetic insights beyond DTI-GWASs, we compared results from 804 DKI-GWASs and 752 DTI-GWASs in the same cohort. To clarify the biological significance of DKI phenotypes, we examined associations between DKI phenotypes and brain health-related outcomes within the CHIMGEN, and explored associations between polygenic risk scores (PRSs) of DKI phenotypes and mental disorders in the UK Biobank. FINDINGS:Of 804 DKI phenotypes, 275 showed significant heritability (P < 0.05; h2 range: 0.143-0.602). We detected 280 significant associations (P < 5 × 10-8), with 38 surviving Bonferroni correction (P < 1.54 × 10-10). These associations were unevenly distributed across chromosomes, DKI phenotype subgroups, and brain structures. Among 229 independent variant-structure associations for DKI, 175 (76.4%) were DKI-specific. We observed 930 associations between DKI phenotypes and brain health-related outcomes (P < 0.05; ten Bonferroni-significant with P < 1.02 × 10-5), and 200 between PRSs and mental disorders (P < 0.05; one Bonferroni-significant with P < 9.61 × 10-5). INTERPRETATION:This study delineates the genetic architecture of brain DKI phenotypes, identifies complementary genetic insights into brain microstructure, and provides biologically relevant endophenotypes for investigating neural mechanisms underlying brain disorders. FUNDING:National Natural Science Foundation of China, National Key Research and Development Program of China, Tianjin Key Medical Discipline Construction Project, and Tianjin Natural Science Foundation.

The mechanism by which the increasing environmental challenge of urbanicity impacts the brain, personality and mental disorders remains unclear. Here, grounded in life history theory, we tested the hypothesis that age at menarche (AAM) mediates the effects of early-life urbanicity on adult regional brain volumes and personality traits associated with mental disorders. In a sample of 2,950 young Chinese women, we discovered that higher levels of early-life urbanicity were associated with earlier AAM, which in turn correlated with reduced medial prefrontal volume and lower levels of agreeableness and reward dependence in adulthood. Urbanicity-related factors, particularly family socioeconomic status, also influenced these neurobehavioral traits through AAM. The urbanicity- and AAM-related brain and personality traits were changed in patients with major depressive disorder and schizophrenia. These findings suggest that life history theory may serve as a mechanism through which early-life urbanicity influences the adult brain and personality traits associated with mental disorders in women. It is unclear how early-life urbanicity influences adult neurobehavioral traits. This study reveals that earlier menarche mediates the relationship between early-life urbanicity and adult neurobehavioral traits associated with mental disorders.

With the worldwide increase in only-child families, it is crucial to understand the effects of growing up without siblings (GWS) on the adult brain, behaviour and the underlying pathways. Using the CHIMGEN cohort, we investigated the associations of GWS with adult brain structure, function, connectivity, cognition, personality and mental health, as well as the pathway from GWS to GWS-related growth environments to brain and to behaviour development, in 2,397 pairs of individuals with and without siblings well matched in covariates. We found associations linking GWS to higher language fibre integrity, lower motor fibre integrity, larger cerebellar volume, smaller cerebral volume and lower frontotemporal spontaneous brain activity. Contrary to the stereotypical impression of associations between GWS and problem behaviours, we found positive correlations of GWS with neurocognition and mental health. Despite direct effects, GWS affects most brain and behavioural outcomes through modifiable environments, such as socioeconomic status, maternal care and family support, suggesting targets for interventions to enhance children's healthy growth.

The brainstem houses numerous nuclei and tracts that serve vital functions. Genome-wide associations with brainstem substructure volumes have been explored in European individuals, yet other ancestries remain under-represented. Here, we conduct cross-ancestry genome-wide association meta-analyses in 103,098 individuals for brainstem and 78,062 individuals for eight substructure volumes, including 7094 Chinese Han individuals. We identify 713 locus-trait associations with brainstem and substructure volumes at P < 5.56 ×10−9, comprising 569 new associations. Two associations show different effect sizes, while 496 associations have similar effect sizes between ancestries. We prioritize 186 genes associated with brainstem volumetric traits. We find both shared and distinct genetic loci, genes, and pathways for midbrain, pons, and medulla volumes, along with the shared genetic architectures related to disease phenotypes and physiological functions. The results provide new insights into the genetic architectures of brainstem and substructure volumes and their genetic associations with brainstem physiologies and pathologies. A cross-ancestry GWAS meta-analyses of brainstem structures identify 713 associations. It reveals shared/distinct genetic architectures across ancestries/substructures and overlaps with neuropsychiatric disorders and physiological functions.

The amygdala is a small but critical multi-nucleus structure for emotion, cognition and neuropsychiatric disorders. Although genetic associations with amygdala volumetric traits have been investigated in sex-combined European populations, cross-ancestry and sex-stratified analyses are lacking. Here we conducted cross-ancestry and sex-stratified genome-wide association analyses for 21 amygdala volumetric traits in 6,923 Chinese and 48,634 European individuals. We identified 191 variant-trait associations (P < 2.38 × 10-9), including 47 new associations (12 new loci) in sex-combined univariate analyses and seven additional new loci in sex-combined and sex-stratified multivariate analyses. We identified 12 ancestry-specific and two sex-specific associations. The identified genetic variants include 16 fine-mapped causal variants and regulate amygdala and fetal brain gene expression. The variants were enriched for brain development and colocalized with mood, cognition and neuropsychiatric disorders. These results indicate that cross-ancestry and sex-stratified genetic association analyses may provide insight into the genetic architectures of amygdala and subnucleus volumes.

National Medical Licensing Examination (NMLE) is the entrance exam for medical practice in China, and its general medical knowledge test (GMKT) evaluates abilities of medical students to comprehensively apply medical knowledge to clinical practice. This study aimed to identify nonacademic predictors of GMKT performance, which would benefit medical schools in designing appropriate strategies and techniques to facilitate the transition from medical students to qualified medical practitioners. In 1202 medical students, we conducted the deletion-substitution-addition (DSA) and structural equation model (SEM) analyses to identify nonacademic predictors of GMKT performance from 98 candidate variables including early life events, physical conditions, psychological and personality assessments, cognitive abilities, and socioeconomic conditions. The candidate variables were assessed using psychometrically or cognitively validated and accepted instruments. We identified seven nonacademic predictors for GMKT performance. Body mass index (BMI) and working memory reaction time showed direct negative effects on GMKT performance. Psychological and personality features (conscientiousness, state anxiety, and openness to experience) indirectly affected GMKT performance via BMI, while socioeconomic conditions (father’s education and mother’s occupation) indirectly affected GMKT performance by influencing psychological and personality features and further BMI. The identified nonacademic predictors for GMKT performance and their pathways may be useful for improving medical education by strengthening favorable and weakening, rectifying, or compensating unfavorable factors that are modifiable.

Brain structure and function show substantial individual differences, finely controlled by genes, environments, and their interactions. Despite the increasing knowledge about genetic and environmental main effects, gene-environment interaction effects on brain phenotypes remain elusive. This study investigates genome-wide by environment (41 exposures) interactions on 598 brain imaging phenotypes in 7084 healthy young adults. Both univariate and multivariate analyses identify 486 significant gene-environment interactions, scattered across the genome, exposome, and phenome. These interactions explain more variances of phenotypes than genetic and environmental main effects (100% of genetic and 96% of environmental main effects are non-significant). Variants with interactions are enriched in intronic and intergenic regions, comprising 79 regulatory variants and 145 associated with brain gene expression. Protein-protein interaction network analyses reveal distinct interaction networks for genes associated with air pollution (hubs: H4C6, SMARCA4, and RPS11) and urbanicity (hubs: CCND1, CALM3, and CDK2) exposures. Genes that interacted with air pollution exposures exhibit enrichment in pathways related to metal ion detoxification and homeostasis. For time-varying exposures, 144 interactions demonstrate sensitive periods, predominantly in childhood (ages 4-7) and adolescence (ages 12-15). These findings highlight the value of genome-wide by exposome-wide interaction studies, which may offer crucial information for optimizing brain health outcomes.

Socioeconomic status (SES) is a time-varying multidimensional construct with ill-defined dimension-specific and age-specific effects on brain and behavior. We investigated these effects in 4,228 young adults. From 16 socioeconomic indicators, assessed for early (0-10 years) and late (>10 years) stages, we constructed family, provincial, family adverse and neighborhood adverse socioeconomic dimensions. Generally, family SES was associated with brain structure and connectivity along with cognitive function, whereas family adverse and neighborhood adverse SES were associated with personality and emotion. Most associations were observed for both early and late-stage SES; however, adjusting for the effect of early stage SES revealed late-stage-specific SES effects. Changes in SES were associated with personality and cognitive function. Cerebellar and medial frontal volumes and functional connectivity within the left frontoparietal network mediated the associations between family SES and memory and openness. These results inform both more precise interventions for reducing the consequences of adverse SES and experimental designs for excluding confounding socioeconomic effects on human health.

Genome-wide association studies of brain imaging phenotypes are mainly performed in European populations, but other populations are severely under-represented. Here, we conducted Chinese-alone and cross-ancestry genome-wide association studies of 3,414 brain imaging phenotypes in 7,058 Chinese Han and 33,224 white British participants. We identified 38 new associations in Chinese-alone analyses and 486 additional new associations in cross-ancestry meta-analyses at P < 1.46 × 10-11 for discovery and P < 0.05 for replication. We pooled significant autosomal associations identified by single- or cross-ancestry analyses into 6,443 independent associations, which showed uneven distribution in the genome and the phenotype subgroups. We further divided them into 44 associations with different effect sizes and 3,557 associations with similar effect sizes between ancestries. Loci of these associations were shared with 15 brain-related non-imaging traits including cognition and neuropsychiatric disorders. Our results provide a valuable catalog of genetic associations for brain imaging phenotypes in more diverse populations.

Abstract With the worldwide increase of only-child families, it is crucial to understand the influence of growth without siblings (GWS) on human health, but there is limited knowledge regarding the effects of GWS on human brain. Besides, existing studies have reported paradoxical associations between GWS and mental health, most likely due to mismatched confounders and overlooked growth environments. Here, using 2,305 pairs of individuals with and without siblings well matched in confounders, we comprehensively examined the impact of GWS on changes in adult brain structure, function, and behaviors, as well as pathways from GWS, growth environments to brain and behaviors. Our findings uncovered novel associations, including GWS being linked to higher language-fiber integrity, lower motor-fiber integrity, larger regional cerebellum volume, and lower frontotemporal spontaneous brain activity. Contrary to stereotypical associations between GWS and problem behaviors, we found positive correlations of GWS with neurocognition and mental health. Despite direct effects, GWS affects most adult brain and behavioral outcomes through modifiable environments, such as socioeconomic status, maternal care, and family support, suggesting targets for interventions to enhance children’s healthy growth.

BACKGROUND:Urbanicity refers to the conditions that are particular to urban areas and is a growing environmental challenge that may affect hippocampus and neurocognition. This study aimed to investigate the effects of the average pre-adulthood urbanicity on hippocampal subfield volumes and neurocognitive abilities as well as the sensitive age windows of the urbanicity effects. PARTICIPANTS AND METHODS:We included 5,390 CHIMGEN participants (3,538 females; age: 23.69 ± 2.26 years, range: 18-30 years). Pre-adulthood urbanicity of each participant was defined as the average value of annual night-time light (NL) or built-up% from age 0-18, which were extracted from remote-sensing satellite data based on annual residential coordinates of the participants. The hippocampal subfield volumes were calculated based on structural MRI and eight neurocognitive measures were assessed. The linear regression was applied to investigate the associations of pre-adulthood NL with hippocampal subfield volumes and neurocognitive abilities, mediation models were used to find the underlying pathways among urbanicity, hippocampus and neurocognition, and distributed lag models were used to identify sensitive age windows of urbanicity effect. RESULTS:Higher pre-adulthood NL was associated with greater volumes in the left (β = 0.100, 95%CI: [0.075, 0.125]) and right (0.078, [0.052, 0.103]) fimbria and left subiculum body (0.045, [0.020, 0.070]) and better neurocognitive abilities in information processing speed (-0.212, [-0.240, -0.183]), working memory (0.085, [0.057, 0.114]), episodic memory (0.107, [0.080, 0.135]), and immediate (0.094, [0.065, 0.123]) and delayed (0.087, [0.058, 0.116]) visuospatial recall, and hippocampal subfield volumes and visuospatial memory showed bilateral mediations for the urbanicity effects. Urbanicity effects were greatest on the fimbria in preschool and adolescence, on visuospatial memory and information processing from childhood to adolescence and on working memory after 14 years. CONCLUSION:These findings improve our understanding of the impact of urbanicity on hippocampus and neurocognitive abilities and will benefit for designing more targeted intervention for neurocognitive improvement.

The study aimed to investigate the neurovascular coupling abnormalities in Leber’s hereditary optic neuropathy (LHON) and their associations with clinical manifestations. Twenty qualified acute Leber’s hereditary optic neuropathy (A-LHON, disease duration ≤ 1 year), 29 chronic Leber’s hereditary optic neuropathy (C-LHON, disease duration > 1 year), as well as 37 healthy controls (HCs) were recruited. The neurovascular coupling strength was quantified as the ratio between regional homogeneity (ReHo), which represents intrinsic neuronal activity and relative cerebral blood flow (CBF), representing microcirculatory blood supply. A one-way analysis of variance was used to compare intergroup differences in ReHo/CBF ratio with gender and age as co-variables. Pearson’s Correlation was used to clarify the association between ReHo, CBF, and neurovascular coupling strength. Furthermore, we applied linear and exponential non-linear regression models to explore the associations among ReHo/CBF, disease duration, and neuro-ophthalmological metrics. Compared with HCs, A_LHON, and C_LHON patients demonstrated a higher ReHo/CBF ratio than the HCs in the bilateral primary visual cortex (B_CAL), which was accompanied by reduced CBF while preserved ReHo. Besides, only C_LHON had a higher ReHo/CBF ratio and reduced CBF in the left middle temporal gyrus (L_MTG) and left sensorimotor cortex (L_SMC) than the HCs, which was accompanied by increased ReHo in L_MTG (p < 1.85e–3, Bonferroni correction). A-LHON and C-LHON showed a negative Pearson correlation between ReHo/CBF ratio and CBF in B_CAL, L_SMC, and L_MTG. Only C_LHON showed a weak positive correlation between ReHo/CBF ratio and ReHo in L_SMC and L_MTG (p < 0.05, uncorrected). Finally, disease duration was positively correlated with ReHo/CBF ratio of L_SMC (Exponential: Radj2 = 0.23, p = 8.66e–4, Bonferroni correction). No statistical correlation was found between ReHo/CBF ratio and neuro-ophthalmological metrics (p > 0.05, Bonferroni correction). Brain neurovascular “dyscoupling” within and outside the visual system might be an important neurological mechanism of LHON.

The hippocampus is critical for memory and cognition and neuropsychiatric disorders, and its subfields differ in architecture and function. Genome-wide association studies on hippocampal and subfield volumes are mainly conducted in European populations; however, other ancestral populations are under-represented. Here we conduct cross-ancestry genome-wide association meta-analyses in 65,791 individuals for hippocampal volume and 38,977 for subfield volumes, including 7,009 individuals of East Asian ancestry. We identify 339 variant–trait associations at P < 1.13 × 10−9 for 44 hippocampal traits, including 23 new associations. Common genetic variants have similar effects on hippocampal traits across ancestries, although ancestry-specific associations exist. Cross-ancestry analysis improves the fine-mapping precision and the prediction performance of polygenic scores in under-represented populations. These genetic variants are enriched for Wnt signaling and neuron differentiation and affect cognition, emotion and neuropsychiatric disorders. These findings may provide insight into the genetic architectures of hippocampal and subfield volumes. Genome-wide association meta-analyses in populations of East Asian and European ancestries identify variant–trait associations for 44 hippocampal traits and provide insight into the genetic architectures of hippocampal and subfield volumes.

Exposure to preadult environmental exposures may have long-lasting effects on mental health by affecting the maturation of the brain and personality, two traits that interact throughout the developmental process. However, environment-brain-personality covariation patterns and their mediation relationships remain unclear. In 4297 healthy participants (aged 18–30 years), we combined sparse multiple canonical correlation analysis with independent component analysis to identify the three-way covariation patterns of 59 preadult environmental exposures, 760 adult brain imaging phenotypes, and five personality traits, and found two robust environment-brain-personality covariation models with sex specificity. One model linked greater stress and less support to weaker functional connectivity and activity in the default mode network, stronger activity in subcortical nuclei, greater thickness and volume in the occipital, parietal and temporal cortices, and lower agreeableness, consciousness and extraversion as well as higher neuroticism. The other model linked higher urbanicity and better socioeconomic status to stronger functional connectivity and activity in the sensorimotor network, smaller volume and surface area and weaker functional connectivity and activity in the medial prefrontal cortex, lower white matter integrity, and higher openness to experience. We also conducted mediation analyses to explore the potential bidirectional mediation relationships between adult brain imaging phenotypes and personality traits with the influence of preadult environmental exposures and found both environment-brain-personality and environment-personality-brain pathways. We finally performed moderated mediation analyses to test the potential interactions between macro- and microenvironmental exposures and found that one category of exposure moderated the mediation pathways of another category of exposure. These results improve our understanding of the effects of preadult environmental exposures on the adult brain and personality traits and may facilitate the design of targeted interventions to improve mental health by reducing the impact of adverse environmental exposures.

Objective:To investigate the MRI features of fibro-adipose vascular anomaly (FAVA).Methods:The clinical, pathological and MRI data of the FAVA patients confirmed clinically and pathologically in Henan Provincial People’s Hospital from January 2016 to June 2021 were retrospectively analyzed, including 17 females and 13 males, aged 4-53 (18.5±12.8) years.Through the analysis of the MRI images of FAVA performance, including the lesion area, shape, signal, the degree of reinforcement, inner structure, outer structure and other image characteristics, summarize the MRI features.Results:The lesions located at the lower leg (12 cases), thigh (12 cases), upper arm (4 cases), forearm (1 case) and trunk (1 case). Twenty-four case of lower limbs. All cases involved the muscular layer, including 21 cases of superficial muscle layer, 7 cases of deep muscle layer, and 2 cases of both. Twenty-three cases of superficial muscle layer. Most of the affected muscles were quadriceps femoris and gastrocnemius. Morphology: all lesions were intramuscular solid masses growing parallel to the long axis of the muscle. There were 11 cases of focal type, 11 cases of locally infiltrating type, and 8 cases of diffuse type. MRI findings: all lesions showed mixed signal. On T1WI, 28 cases showed cloud-like, band-like and patchy high signal on the background of medium and high signal. On T2WI-FS, all the 30 cases showed low to medium signal areas on the background of high signal, which were dendrimer, ribbon and cloud-like. The lesions showed moderate to obvious heterogeneous progressive enhancement. Twenty-seven lesions had different shapes of vascular shadow, and 28 lesions had drainage vein shadow adjacent to the lesions, 24 of which were located at the proximal end of the lesions. Fascial tail sign was found at the periphery of the lesions in 26 cases, of which 23 cases were located at the upper and lower ends of the lesions.Conclusion:FAVA is a complex vascular malformation with unclear pathological classification. MRI usually shows a solid mass in the superficial muscle layer of the lower limbs parallel to the long axis of the muscle, with cloud-like, band-like, and patchy hyperintensity on the background of high signal on T1WI, and dendritic, band-like, and cloud-like hypointensity on the background of high signal on T2WI-FS, which is helpful for the diagnosis of FAVA. Combined with the data of fascial tail sign, draining vein and clinical manifestations, the diagnosis of FAVA can be confirmed to a certain extent, which can provide reference and basis for clinical decision making.

Purpose: The study aimed to unravel abnormal cerebral blood flow (CBF) in patients with Leber's hereditary optic neuropathy (LHON) using arterial spin labeling (ASL) and to investigate the associations among disrupted CBF, disease duration, and neuro-ophthalmological impairment. Methods: ASL perfusion imaging data was collected from 20 patients with acute LHON, 29 patients with chronic LHON, and 37 healthy controls. We used a one-way analysis of covariance to test the intergroup differences in CBF. Linear and nonlinear curve fit models were applied to explore the associations among CBF, disease duration, and neuro-ophthalmological metrics. Results: Brain regions differed in LHON patients, including the left sensorimotor and bilateral visual areas (p < 0.05, cluster-wise family-wise error correction). Acute and chronic LHON patients demonstrated lower CBF in bilateral calcarine than the healthy controls. Chronic LHON had lower CBF in the left middle frontal gyrus and sensorimotor cortex, and temporal-partial junction than the healthy controls and acute LHON. A significant logarithmic negative correlation was shown between CBF of left middle frontal gyrus and disease duration. A significant linear positive correlation was found between retinal nerve fiber layer thickness and CBF in left middle frontal gyrus, and negative correlations between loss of variance and CBF in left middle frontal gyrus and sensorimotor cortex (p < 0.05, Bonferroni correction). Conclusion: LHON patients exhibited reduced CBF in the visual pathway, sensorimotor and higher-tier cognitive areas. Disease duration and neuro-ophthalmological impairments can influence the metabolism of non-visual areas.

Genome-wide association studies of brain imaging phenotypes are mainly performed in European populations, but other populations are severely under-represented. Here, we conducted Chinese-alone and trans-ancestral genome-wide association studies of 3,414 brain imaging phenotypes in 7,058 Chinese and 33,224 European individuals. We identified 37 novel variant-phenotype associations in Chinese-alone analyses and 459 additional novel associations in trans-ancestral meta-analyses under the thresholds of P < 1.46 × 10 − 11 for discovery and P < 0.05 for replication. We pooled genome-wide significant associations for brain imaging phenotypes identified in either single-ancestral or trans-ancestral analyses into 6,361 independent significant associations. These associations were unevenly distributed in the genome and across the brain phenotypic subgroups and demonstrated significant enrichment for nervous system development and signal transduction. We further categorized the 4,890 pooled genome-wide significant associations whose index variants were included in both Chinese and European analyses into 43 ancestry-specific and 3,524 ancestry-shared associations. Loci of the 6,361 pooled genome-wide significant associations for brain imaging phenotypes were shared by 16 brain-related non-imaging traits including cognition, personality, risk behavior, addiction, and neuropsychiatric disorders. Our results provide a valuable catalog of genetic associations for brain imaging phenotypes in diverse populations.

Decreasing X-ray tube voltage is an effective way to reduce radiation and contrast dose, especially in non-obese patients. The current study focuses on CTA in non-obese patients to evaluate image quality and feasibility of 80-kV acquisition protocols with varying iodine delivery rates (IDR) and contrast concentrations in routine clinical practice. A prospective observational study in patients ≥ 18 years and ≤ 90 kg referred for coronary or craniocervical CTA at 10 centers in China (ClinicalTrials.gov: NCT02840903). Patients were divided into four groups: a standard 100-kV protocol (370 mgI/ml, IDR 1.48 gI/s), and three 80-kV protocols (370 mgI/ml, IDR 1.2 gI/s; 300 mgI/ml, IDR 1.2 gI/s; 300 mgI/ml, IDR 0.96gI/s). The primary outcome was contrast opacification of target vascular segments. Secondary outcomes were image quality (contrast-to-noise ratio, signal-to-noise ratio, visual image quality, and diagnostic confidence assessment), radiation, and iodine dose. From July 2016 to July 2017, 1213 patients were enrolled: 614 coronary and 599 craniocervical CTA. The mean contrast opacification was ≥ 300 HU for 80-kV 1.2 gI/s IDR scanned segments; IDR 0.96 gI/s led to lower opacification. Image quality and diagnostic confidence were fair to excellent (≥ 98% of images), despite lower contrast-to-noise ratios and signal-to-noise ratios in 80-kV images. Compared to the standard protocol, 80-kV protocols led to 44–52% radiation dose reductions (p < 0.001) and 19% iodine dose reductions (p < 0.001). Eighty-kilovolt 1.2 gI/s IDR protocols can be recommended for coronary and craniocervical CTA in non-obese patients, reducing radiation and iodine dose without compromising image quality. • Using low-voltage scanning CTA protocols, in which tube voltage and iodine delivery rate are reduced proportionally (voltage: 80 kV, IDR: 1.2 gI/s), reduces radiation and contrast dose without compromising image quality in routine clinical practice. • Reducing iodine delivery rate beyond direct proportionality to tube voltage is not beneficial.