PURPOSE:To develop and externally validate a non-invasive framework for quantifying brain amyloid-β (Aβ) deposition using magnetic resonance fingerprinting (MRF) and neural network-based decoding, with positron emission tomography (PET) as the reference standard. METHODS:This prospective multi-site study included 44 participants from 2 sites who had undergone, or were scheduled to undergo, Aβ PET within 1 year. MRF was performed on a 3T MR system using a 2D fast imaging with steady-state precession sequence with B1 correction, covering the whole brain in 9.5 min. PET images were co-registered to the MRF space, and regional amyloid load was calculated using an automated template-based pipeline. An inverse mapping function was implemented to convert MRF signals into amyloid burden maps. Repeatability, agreement with PET-based centiloid values, and associations with cognitive scores were evaluated. RESULTS:The generated amyloid maps were visually similar to PET images. Test-retest analysis showed high repeatability, with a coefficient of variation of 1.8 ± 1.3% and an intraclass correlation coefficient of 0.84. In the external test set, MRF-based measurements correlated significantly with PET centiloid scores (Spearman's ρ = 0.589, P = 0.015) and Montreal Cognitive Assessment scores (ρ = -0.543, P = 0.020). CONCLUSION:The proposed framework enables non-invasive Aβ mapping using a clinically feasible MRI protocol and may support repeated assessment for monitoring during anti-amyloid treatment.

Background Parkinson's disease with subjective cognitive decline (PD-SCD), defined as self-perceived cognitive decline in the absence of objective impairment, is associated with an increased risk of progression to mild cognitive impairment (PD-MCI) and dementia. Cerebral blood flow (CBF) imaging may provide insight into functional alterations preceding measurable cognitive decline. Objective To characterize regional CBF patterns in PD-SCD and compare them with those in PD with normal cognition (PD-NC) and PD-MCI. Methods A total of 140 patients with PD were classified as PD-NC (n = 32), PD-SCD (n = 31), or PD-MCI (n = 77) using Movement Disorder Society (MDS) Task Force PD-MCI Level II criteria in conjunction with commonly used assessments of SCD. All participants underwent clinical evaluation, depression assessment, MRI, and 123I-iodoamphetamine single-photon emission computed tomography (SPECT). Whole-brain voxel-wise comparisons of tracer uptake ratios were performed using statistical parametric mapping, adjusting for age, sex, SPECT scanner, and depressive symptom scores. Results Compared with PD-NC, PD-SCD demonstrated significantly increased CBF in bilateral frontal and temporal regions (p < 0.01, family - wise error [FWE] corrected) and the left cerebellum (p < 0.05, FWE corrected), despite preserved cognition. PD-MCI exhibited bilateral frontal and temporal hypo-perfusion relative to PD-SCD (p < 0.01, FWE corrected). Conclusion PD-SCD is associated with frontal and temporal hyper-perfusion relative to PD-NC and PD-MCI. These regions partially overlap with cortical areas vulnerable to thinning in PD dementia, supporting the hypothesis that hyper-perfusions may reflect compensatory network responses in regions susceptible to structural degeneration.

BackgroundTransient global amnesia (TGA) often shows tiny punctate hippocampal CA1 lesions on diffusion-weighted imaging (DWI). Whether these lesions represent truly transient structural alterations remains unsettled. Ultra–high-field 7-tesla (7 T) MRI increases spatial resolution and lesion conspicuity. However, the evolution of hippocampal T2 signal at 7 T from the acute phase through short-term follow-up has not been systematically examined.ObjectiveTo determine, using serial 7 T MRI, whether hippocampal T2-weighted imaging (T2WI) abnormalities visible in acute TGA are consistently detectable acutely and completely disappear by approximately 2 weeks.MethodsSingle-center consecutive case series of six patients with clinically defined TGA and DWI-confirmed CA1 lesions who underwent serial 7 T MRI, including acute imaging and follow-up at 14–18 days. The primary outcome was complete resolution of hippocampal T2 hyperintensity. Secondary outcomes were acute T2 detection rate, lesion distribution, and concordance with DWI.ResultsSix patients (4 men), median age 69 years (range 50–76), all fulfilled the diagnostic criteria of TGA and no neurological deficits. Acute 7 T MRI was performed at a median of 37 h after symptom onset. Acute phase: All 6/6 showed focal hippocampal CA1 hyperintensity on 7 T T2WI, colocalizing with DWI/ADC abnormalities. Follow-up (day 15–18): T2 hyperintensity resolved in 6/6 with no visible residual signal abnormality or structural atrophy. Follow-up 7 T DWI demonstrated complete disappearance of the previously identified diffusion abnormalities in all patients. Interpretation: Even at ultra-high field, hippocampal T2 abnormalities are fully reversible within approximately 2 weeks.ConclusionSerial 7 T MRI demonstrates that hippocampal T2WI lesions in TGA are consistently visible acutely and uniformly disappear by 2 weeks, providing high-field structural evidence that typical TGA is a transient phenomenon. These findings refine the temporal profile of hippocampal signal evolution and contribute to mechanistic understanding of CA1 vulnerability in TGA.

Certain brain tumors exhibit cystic components. MRI is particularly effective in characterizing the location, enhancement, and morphology of these cystic regions, enabling radiologists to narrow the differential diagnosis. Cystic components are often associated with circumscribed tumors and may be linked to favorable outcomes. High-grade tumors such as glioblastoma can also occasionally exhibit cystic components. Here, we summarize the imaging characteristics of representative cystic brain intraparenchymal neoplasms, including hemangioblastoma, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, ganglioglioma, desmoplastic infantile ganglioglioma/astrocytoma, central neurocytoma, dysembryoplastic neuroepithelial tumor, ependymoma, glioblastoma, and metastases. This review aims to provide MRI features that facilitate differentiation of these tumors and support appropriate clinical management.

Early detection and activity assessment of posterior cerebral artery (PCA) involvement in moyamoya disease (MMD) are challenging. We aimed to assess the cross-sectional association between PCA involvement and PCA wall enhancement on vessel wall MRI (DANTE T1-SPACE). We analyzed consecutive patients with MMD who underwent both non-contrast-enhanced and contrast-enhanced DANTE T1-SPACE. Positive wall enhancement was defined as location-appropriate arterial wall enhancement with an enhancement ratio ≥ 1.5. PCA involvement was graded 0–2 on MRA obtained during the same period. Of 368 hemispheres from 184 patients, 56 (15.2

OBJECTIVE:Selective intraindividual weakness in successive processing, which is a unique verbal working memory scale included in the Das-Naglieri Cognitive Assessment System (CAS), is considered one of the intrinsic neurocognitive characteristics in pediatric moyamoya disease (MMD). The aim of the study was to elucidate the association between cerebral blood flow (CBF) and weakness in successive processing, and to identify regions related to the weakness. METHODS:The present cross-sectional study included children who had been diagnosed with MMD and were assessed using neuropsychological tests before surgery between June 2016 and December 2023. According to the CAS manual, intraindividual difference was calculated by subtracting the mean of the 4 standard scores from each standard score. Each patient was classified as either manifesting "intraindividual weakness in successive processing" (intraindividual difference of successive processing < 0) or not (intraindividual difference of successive processing ≥ 0), and CBF acquired with resting-state SPECT was compared between groups. Three-dimensional stereotactic surface projection (3D-SSP) was also used for topographical comparison of CBF. RESULTS:Of 51 children (mean age ± SD at admission 8.0 ± 2.6 years) who underwent preoperative neuropsychological tests, 43 were included in the CBF analysis. Both standard scores and intraindividual difference of the CAS significantly varied across 4 domains (p = 0.006 and p < 0.001, respectively), and those of successive processing were the lowest. Of the children analyzed, 35 (68.7%) were classified as having intraindividual weakness in successive processing. Multiple logistic regression analysis revealed the severest ischemic grade was significantly associated with intraindividual weakness in successive processing (OR 5.49 [95% CI 1.12-27.06]). Three-dimensional SSP analysis demonstrated a significant CBF decrease in the left dorsolateral and medial prefrontal cortexes in the children showing intraindividual weakness in successive processing compared with those who did not. CONCLUSIONS:Intraindividual weakness in successive processing typical of MMD might be associated with reduced CBF in the dorsolateral and medial prefrontal cortex, predominantly in the left hemisphere. Further studies in this area could contribute to the improvement of long-term social outcomes for patients with MMD.

BACKGROUND:Vessel-specific bolus arrival time (BAT) has become calculated with higher spatiotemporal resolution on dynamic contrast-enhanced magnetic resonance imaging using the Golden-angle RAdial Sparse Parallel (GRASP) technique. However, its utility in moyamoya disease (MMD) is unclear. PURPOSE:To evaluate the relationship between BAT and arterial stenosis/periventricular anastomosis (PA) development, and the utility of BAT in MMD. STUDY TYPE:Retrospective. SUBJECTS:Sixty-one preoperative MMD patients (mean ± standard deviation age, 31.0 ± 20.4 years; 46 females; 25 children). FIELD STRENGTH/SEQUENCE:3-T, radial volume interpolated breath-hold examination sequence, and three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA). ASSESSMENT:Arterial stenosis, including internal carotid artery, middle cerebral artery (MCA), and posterior cerebral artery, and PA development, including lenticulostriate artery, thalamic perforator, and choroidal channel, were scored on TOF-MRA. Differences in BAT (ΔBATs) between the right and left regions of interest (ROIs), including MCA M2, basal ganglia, thalamus, and choroid plexus, were compared with the right and left arterial stenosis score differences. ΔBATs between the MCA M2 and the ipsilateral basal ganglia, thalamus, and choroid plexus were compared with PA scores. A logistic regression model including ΔBAT was developed to assess the associations with recent transient ischemic attacks (TIAs). STATISTICAL TESTS:Kappa statistic, Friedman test, intraclass correlation coefficient, one-way analysis of variance, Tukey-Kramer test, logistic regression analysis, and receiver operating characteristic analysis. p < 0.05 was considered significant. RESULTS:ΔBATs between the right and left ROIs increased by 0.11-1.76 s depending on arterial stenosis score differences. ΔBATs between the MCA M2 and the ipsilateral ROIs decreased by 0.32-1.46 s with higher PA scores. Models including ΔBAT for recent TIAs showed areas under the curve of 0.81 in children and 0.78 in adults. DATA CONCLUSION:BAT was indicative of arterial stenosis and PA development, and was associated with recent TIAs in MMD. LEVEL OF EVIDENCE:3 TECHNICAL EFFICACY: Stage 2.

The advances in artificial intelligence (AI) technology in recent years have been remarkable, and the field of radiology is at the forefront of applying and implementing these technologies in daily clinical practice. Radiologists must keep up with this trend and continually update their knowledge. This narrative review discusses the application of artificial intelligence in the field of musculoskeletal imaging. For image generation, we focused on the clinical application of deep learning reconstruction and the recently emerging MRI-based cortical bone imaging. For automated diagnostic support, we provided an overview of qualitative diagnosis, including classifications essential for daily practice, and quantitative diagnosis, which can serve as imaging biomarkers for treatment decision making and prognosis prediction. Finally, we discussed current issues in the use of AI, the application of AI in the diagnosis of rare diseases, and the role of AI-based diagnostic imaging in preventive medicine as part of our outlook for the future.

BACKGROUND:A dual-syndrome hypothesis, which states the cognitive impairments in Parkinson's disease (PD) are attributable to frontostriatal dopaminergic dysregulation and cortical disturbance-each associated with attention/executive and memory/visuospatial dysfunction, respectively-has been widely accepted. This multisystem contribution also underlies highly heterogeneous progression rate to dementia. METHODS:Nondemented PD patients who underwent [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([123I]FP-CIT) SPECT and neuropsychological examinations were enrolled. Patients who agreed to participate and age- and sex-matched healthy controls (HCs) also underwent 7-T MRI. Patients were classified as cognitively normal (PD-CN) or mild cognitive impairment (PD-MCI) following the level II criteria of Movement Disorder Society Guideline. RESULTS:A total of 155 patients (PD-CN/PD-MCI 74/81) were enrolled, whereas 76 patients (PD-CN/PD-MCI 35/41) and 56 HCs underwent 7 T-MRI. The caudate [123I]FP-CIT uptake in PD was correlated with the performance of attention/working memory (trail-making test [TMT]-A and symbol digit modality test) and executive (TMT-B) domains. In contrast, the regional cortical thickness in the left frontotemporal and right frontal lobes in PD was correlated with performance of memory (Hopkins verbal learning test-revised delayed recall) and visuospatial (judgment of line orientation) domains. Moreover, compared to 37 HCs with a Montreal Cognitive Assessment score of >25, PD-CN patients showed broad occipitoparietal cortical thinning. CONCLUSIONS:We demonstrated distinctive impairments of dopaminergic frontostriatal deficits and cortical degeneration as neural bases for the dual-syndrome hypothesis. Our findings suggest that occipitoparietal lobe thinning occurs at a cognitively normal stage, and additional frontotemporal lobe thinning underlies impairments in the memory and visuospatial domains at the PD-MCI stage.

BACKGROUND:Neovascularization contributes to plaque vulnerability in carotid artery stenosis. We aimed to assess the association between adventitial enhancement, which reflects neovascularization, on contrast-enhanced magnetic resonance imaging (MRI), and carotid plaque volume and clinical outcomes. METHODS:We retrospectively analyzed 72 patients with 75 carotid plaques who underwent preoperative contrast-enhanced MRI using a delay alternating with nutation for tailored excitation-prepared T1-weighted turbo spin echo (DANTE T1-SPACE) sequence at Kyoto University Hospital (April 2019-March 2025). Adventitial enhancement was visually graded across the entire lesion on postcontrast DANTE T1-SPACE as category 0 (no enhancement), category 1 (<50% of outer wall circumference), or category 2 (≥50%). Plaque volume was measured from precontrast DANTE T1-SPACE. Clinical outcomes included symptomatic events and ipsilateral cerebral ischemic lesions. Intraplaque hemorrhage (IPH) presence and volume were also evaluated. RESULTS:Of the 75 plaques, 9 were category 0, 40 category 1, and 26 category 2. The proportion of either symptomatic plaques or plaques with cerebral ischemic lesions increased across categories: 11% (n = 1), 50% (n = 20), and 62% (n = 16) (P = 0.018). Mean plaque volumes were 0.59, 0.67, and 0.88 mL, respectively (P = 0.004). No significant trend was seen in IPH frequency or volume. Among plaques without IxPH, volume still increased across categories: 0.27, 0.60, and 0.92 mL (P = 0.005). CONCLUSIONS:Whole-lesion adventitial enhancement on DANTE T1-SPACE MRI may serve as a noninvasive imaging biomarker of plaque burden and vulnerability for risk stratification in carotid artery stenosis.

BackgroundConventional MRI sequences are insufficient for the detailed depiction of intracranial atherosclerotic disease (ICAD) plaques. The aim of this study was to investigate the association between ischemic events and intracranial atherosclerotic plaque characteristics using a high-resolution T1-weighted black-blood MRI technique (DANTE T1-SPACE) in the anterior circulation in the Japanese population.MethodsPatients with a total of 108 lesions causing ≥40% stenosis on the C1–5 segments of the intracranial internal carotid artery (ICA) or M1 segment of the middle cerebral artery (MCA) were included. Hyperintense plaques (HIPs) were defined as plaques with a spot of signal intensity (SI) higher than 1.5-fold SI of the ipsilateral temporal muscle on DANTE T1-SPACE. The vessel wall lesions were divided into symptomatic and asymptomatic groups. The lesions in the symptomatic group were classified as artery-to-artery embolism, hemodynamic infarction, cardiac embolism, undetermined and transient ischemic attack (TIA).ResultsAmong the 108 plaques, 19 were symptomatic and 89 were asymptomatic. The percentage of HIPs in the symptomatic group was significantly higher than in the asymptomatic group (57.9% vs. 24.7%, p = 0.01). In the symptomatic group, the proportion of HIPs in the A-to-A embolism subgroup was higher than in the other subgroups.ConclusionsDANTE T1-SPACE may aid in the identification of intracranial plaques with imaging characteristics suggestive of increased stroke risk, particularly hyperintensity potentially reflecting intraplaque hemorrhage.

The efficacy of 2D turbo gradient- and spin-echo diffusion-weighted imaging with non-Cartesian BLADE trajectory (TGSE-BLADE DWI) has not been well studied for acute stroke due to its long acquisition time. This study was performed to compare distortion, artifacts and image quality between single-shot echo planar imaging (SS-EPI) DWI and TGSE-BLADE DWI with acquisition time reduced to 1 min by simultaneous multi-slice (SMS) imaging, and to evaluate the diagnostic performance of TGSE-BLADE DWI for acute infarctions. Total 104 patients with a past history of stroke or symptoms suspicious for acute infarction or who had undergone surgery for brain tumor within two days were prospectively enrolled. Ten lesions in 9 patients were diagnosed as acute or subacute infarction and were detectable only in TGSE-BLADE DWI but not in SS-EPI DWI. Scores for geometric distortion, susceptibility artifacts, overall image quality, lesion conspicuity and diagnostic confidence were lower for SS-EPI DWI than TGSE-BLADE DWI (p ≤ .001). Distortion was significantly worse in SS-EPI DWI than TGSE-BLADE DWI (p < .001). SNR of centrum semiovale was significantly higher in SS-EPI DWI than TGSE-BLADE DWI (p < .001). One-minute TGSE-BLADE DWI showed better image quality than SS-EPI DWI in terms of distortion and artifacts, and higher diagnostic performance for acute infarctions.

To differentiate between Parkinson’s Disease (PD) and healthy controls by using integrated analysis of PD-specific MR findings including deformation of the substantia nigra pars compacta (SNpc), signal loss in neuromelanin (NM) sensitive MRI, and iron deposition in the deep gray matter (DGM) structures. Patients with PD and healthy controls were recruited between August 2022 and December 2023. All subjects underwent 3 T MRI including a magnetization transfer contrast (MTC) and a double flip angle multi-echo protocol as part of Strategically Acquired Gradient Echo (STAGE). The data analysis included detecting the presence of Nigrosome-1 (N1) sign in the SNpc, signal intensity and volume of NM content and iron quantification through quantitative susceptibility mapping (QSM) in DGMs. The 3D regions of interest were manually demarcated on QSM maps. Mean susceptibility values from global analysis (whole structure) as well as regional high iron analysis (age-based threshold) were extracted for each individual structure. Univariate and multivariate analyses were performed using these parameters. Nineteen patients with PD (68.0 ± 8.0 years, 10 males, Hoehn and Yahr scale 1 (n = 1), 2 (n = 13), 3 (n = 4), 4 (n = 1)) and 21 healthy controls (68.3 ± 8.6 years, 12 males) were enrolled. Discriminating PD from controls was successful using each method: N1 sign (P < 0.001), NM volume (P < 0.001), susceptibility values of global analysis (caudate, P < 0.001; putamen, P < 0.001; pulvinar, P = 0.006), regional analysis (putamen, P < 0.001; pulvinar, P = 0.009, thalamus, P = 0.008). Stepwise logistic regression analyses were performed, and the best model was created using N1 sign, NM volume, regional analysis (putamen, red nucleus and thalamus) (area under the curve of 0.99). Integrated analysis of PD specific MR findings including N1 sign, NM volume, and iron content in the DGM structures robustly discriminates between PD and healthy controls.

BACKGROUND:Late-onset temporal lobe epilepsy (TLE) sometimes manifests with enlargement of the amygdala or hippocampus. This study aimed to clarify the yet unknown clinical significance of amygdala-hippocampal enlargement in late-onset TLE. METHODS:We retrospectively analyzed the late-onset TLE (≥ 60 years old) patients admitted to Kyoto University Hospital between 2000 and 2019. To investigate whether the patient group has enlarged amygdala or hippocampus compared to the healthy control, we performed MRI volumetry with hippocampal subfield segmentation. Furthermore, to evaluate the associations of amygdala or hippocampal enlargement with clinical manifestations, we analyzed the relationship between volume changes and seizure semiology, interictal epileptiform discharges (IED) on electroencephalography, Wechsler Memory Scale-Revised, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and neural autoantibodies. RESULTS:We analyzed 33 patients (19 male. Age: mean/median/SD/range = 68.8/69/5.0/61-82. Epilepsy onset: 64.9/64/4.1/60-77 years. Years after epilepsy onset: 3.9/4/2.6/1-14 years). MRI volumetry revealed (1) an increase in the volume of the left amygdala and left hippocampus-amygdala transition area (HATA) and (2) a volume decrease in the bilateral ventral diencephalon, compared to healthy subjects. FDG-PET revealed glucose hypometabolism in the bilateral presubiculum and left hippocampal tail (p < 0.05, Wilcoxon rank-sum test). Memory impairment was more severe in patients with enlarged HATA or left amygdala (left HATA, p = 0.0121; right HATA, p = 0.0039; left amygdala, p = 0.0285; MANOVA). The hippocampal volume ipsilateral to the IED was larger than that contralateral to the IED (p = 0.0053, Wilcoxon rank-sum test). The left hippocampal volume significantly differed depending on IED prevalence (p = 0.0039, ANOVA), where higher IED prevalence was associated with larger hippocampal volume. SIGNIFICANCE:The present study provides the supporting findings for the association of amygdala-hippocampal enlargement with IED and memory impairment in late-onset TLE, suggesting that amygdala-hippocampal enlargement is a clinically significant indicator of epileptic excitability and memory impairment.

To investigate vessel delineation and image quality of ultra-high-resolution (UHR) CT angiography (CTA) reconstructed using deep learning reconstruction (DLR) optimised for brain CTA (DLR-brain) in moyamoya disease (MMD), compared with DLR optimised for body CT (DLR-body) and hybrid iterative reconstruction (Hybrid-IR). This retrospective study included 50 patients with suspected or diagnosed MMD who underwent UHR brain CTA. All images were reconstructed using DLR-brain, DLR-body, and Hybrid-IR. Quantitative analysis focussed on moyamoya perforator vessels in the basal ganglia and periventricular anastomosis. For these small vessels, edge sharpness, peak CT number, vessel contrast, full width at half maximum (FWHM), and image noise were measured and compared. Qualitative analysis was performed by visual assessment to compare vessel delineation and image quality. DLR-brain significantly improved edge sharpness, peak CT number, vessel contrast, and FWHM, and significantly reduced image noise compared with DLR-body and Hybrid-IR (P < 0.05). DLR-brain significantly outperformed the other algorithms in the visual assessment (P < 0.001). DLR-brain provided superior visualisation of small intracranial vessels compared with DLR-body and Hybrid-IR in UHR brain CTA.

Appropriate response assessment criteria are crucial for accurate evaluation of clinical trial outcomes, and numerous criteria have been proposed to address this need. With the introduction of Response Assessment in Neuro-Oncology (RANO) criteria version 2.0 (RANO 2.0) in 2023, response assessment in gliomas has evolved significantly, requiring both clinicians and radiologists to develop a comprehensive understanding of its modifications and implementation. This review first provides an overview of standard management and imaging schedule in glioma treatment. We then review the basic framework of RANO 2.0, inherited from previous response criteria, with particular emphasis on major modifications to this framework: the implementation of the Brain Tumor Imaging Protocol and the adoption of post-radiation scan as the baseline scan. Additionally, we analyze critical changes in response evaluation and interpretation, specifically focusing on the role of preliminary progressive disease assessment with confirmation scans, and the elimination of T2/FLAIR lesion measurements from enhancing tumor assessment. Through illustrative clinical cases, we demonstrate the practical application of these modifications and discuss the implementation of three distinct imaging-based categories: enhancing tumor, non-enhancing tumor, and tumors with both enhancing and non-enhancing components (in short, mixed tumor). This comprehensive narrative review provides clinicians with practical guidance for implementing RANO 2.0 in their clinical practice.

Observation of the clearance of gadolinium-based contrast agents (GBCA) in patients with cerebral infarction and Moyamoya disease (MMD) using vessel-wall MRI (VW-MRI). This prospective study included 11 patients with recent cerebrovascular disorder and 6 patients with MMD who were scheduled for VW-MRI. All participants underwent whole brain delay alternating with nutation for tailored excitation-prepared T1-weighted variable flip angle turbo spin echo (DANTE T1-SPACE) imaging before, immediately after, and 1–6 h after gadolinium injection. Additionally, a phantom experiment was conducted to assess the signal intensity according to T1 values using DANTE T1-SPACE and 3D real inversion recovery sequences. All five large infarction cases (≥ 5 cm) had delayed meningeal enhancement on the ipsilateral side, while none of the remaining six small infarction cases (< 5 cm) exhibited delayed meningeal enhancement on MRI. More than half of the entire cases had delayed white matter enhancement adjacent to the infarction. No MMD cases showed delayed enhancement outside postoperative regions. In the phantom experiment, DANTE T1-SPACE (TR = 700–1300 ms) demonstrated stable signal intensity across a T1 range of approximately 500–1000 ms. This T1 range corresponds to signal intensity ≈ 200–600 typically observed in regions showing delayed enhancement in clinical stroke and MMD cases. Delayed meningeal enhancement observed in patients with large cerebral infarctions likely reflects alterations in brain clearance pathways. The absence of such enhancement in MMD supports that these enhancements are not attributable to collateral circulation. Phantom validation confirmed that the imaging parameters used in the DANTE T1-SPACE sequence were sufficient to detect subtle contrast enhancement in the clinically relevant T1 range.

BACKGROUND:Carotid artery stenosis is a major cause of stroke. Non-contrast MR angiography (MRA) using time-spatial labeling inversion pulse (Time-SLIP) may offer potential advantages over 3D time-of-flight (TOF)-MRA for simultaneous visualization of carotid, vertebral, and subclavian arteries, but remains uninvestigated. PURPOSE:To determine optimal black blood inversion time (TI) for visualizing the carotid and subclavian arteries using three-dimensional (3D) fast field echo (FFE) Time-SLIP MRA, and to compare its image quality with 3D TOF-MRA. STUDY TYPE:Prospective. SUBJECTS:11 healthy adults (23-57 years, five females) and 4 patients (76-93 years, three females) with cervical vascular abnormalities. All patients had ICA stenosis. One patient exhibited ECA stenosis. FIELD STRENGTH/SEQUENCE:3-T, 3D FFE with Time-SLIP using four TIs (1200-1800 ms) for healthy, 3D balanced steady-state free precession (bSSFP) with Time-SLIP using TI = 1600 for patients, and 3D TOF-MRA for all subjects, covering the cervical and subclavian arteries. ASSESSMENT:For healthy subjects, relative signal intensity (SI) was measured using ROI for both sides of the carotid, vertebral, and subclavian arteries. For the same locations, vessel visibility was independently scored by three board-certified radiologists. Patient images were qualitatively assessed for vessel visibility, abnormality, and artifacts. STATISTICAL TESTS:Friedman and Wilcoxon signed-rank tests for pairwise comparisons of vessel visibility. A Bonferroni-corrected significance threshold of p < 0.005 (= 0.05/10) was used. RESULTS:In volunteer scans, relative SI for TI = 1600 was highest, while TI = 1800 showed the best visibility scores. 3D TOF-MRA showed limitations in subclavian and brachiocephalic arteries due to low vessel-to-background contrast. In patients, FFE-based Time-SLIP provided better subclavian artery depiction than bSSFP-based Time-SLIP. DATA CONCLUSION:3D FFE with Time-SLIP may enable high-quality simultaneous visualization of the carotid and subclavian arteries when compared to 3D TOF-MRA. In patients with vascular abnormalities, 3D FFE may provide superior subclavian artery depiction compared to 3D TOF-MRA and 3D bSSFP. EVIDENCE LEVEL:2. TECHNICAL EFFICACY:Stage 2.