Clinical Role of Brain PET in Alzheimer Disease in the Era of Disease-Modifying Therapies

疾病修正疗法时代脑正电子发射断层扫描（PET）在阿尔茨海默病中的临床作用

Alzheimer disease (AD) is the leading cause of dementia, with an estimated 6.9 million Americans aged 65 and older living with Alzheimer dementia today, with this number projected to grow to 13.8 million by 2060. Amyloid and τ accumulation underpin our understanding of the pathophysiology of AD, with the abnormal accumulation of these proteins leading to neurodegeneration. With the recent approval of antiamyloid monoclonal antibody therapies for patients with early-stage Alzheimer disease by the Food and Drug Administration, there is renewed energy and focus on brain imaging for diagnosis, triage, and monitoring of patients with neurodegenerative disease. Furthermore, PET imaging of amyloid and τ has revolutionized our understanding of dementia progression and staging, and influences patient management in the clinical setting. We aim to update radiologists on the evolving role of amyloid and τ PET in clinical practice, emphasizing the need for standardized workflows and the integration of molecular imaging data with other disease biomarkers. We also discuss the clinical implications of amyloid and τ PET, including their impact on diagnosis and treatment decisions, as well as the challenges of reimbursement and workforce capacity. With recent shifts in the AD management landscape, it is crucial for radiologists to keep abreast of recent advances in clinical practice, thereby ensuring effective patient care.

阿尔茨海默病（AD）是导致痴呆的主要原因，目前估计有690万65岁及以上的美国人患有阿尔茨海默病性痴呆，预计到2060年这一数字将增至1380万。淀粉样蛋白和τ蛋白的积累是我们理解AD病理生理学的基础，这些蛋白质的异常积累会导致神经退行性病变。随着美国食品药品监督管理局最近批准针对早期阿尔茨海默病患者的抗淀粉样蛋白单克隆抗体疗法，人们在利用脑成像对神经退行性疾病患者进行诊断、分流和监测方面重新投入了精力并给予了关注。此外，淀粉样蛋白和τ蛋白的正电子发射断层扫描（PET）成像彻底改变了我们对痴呆进展和分期的理解，并影响着临床环境中的患者管理。我们旨在让放射科医生了解淀粉样蛋白和τ蛋白PET在临床实践中不断演变的作用，强调需要标准化工作流程以及将分子成像数据与其他疾病生物标志物相结合。我们还讨论了淀粉样蛋白和τ蛋白PET的临床意义，包括它们对诊断和治疗决策的影响，以及报销和人员配备方面的挑战。随着AD管理领域最近的变化，放射科医生紧跟临床实践的最新进展至关重要，这样才能确保为患者提供有效的护理。

REF: Franceschi AM, Keir G, Benzinger TLS, et al. Clinical Role of Brain PET in Alzheimer Disease in the Era of Disease-Modifying Therapies. AJNR Am J Neuroradiol. 2025;46(8):1521-1527. Published 2025 Aug 1. doi:10.3174/ajnr.A8738 PMID: 40639970

Neuroradiology Fellowship Programs: A Comprehensive Guide for Neuroradiology Fellowship Program Directors

神经放射学专科培训项目：神经放射学专科培训项目主任综合指南

The scope of responsibilities and time commitment required for program directors (PDs) of neuroradiology fellowship programs has become quite substantial over the past decade. PDs must continually refine and document a robust, effective curriculum that meets growing accreditation requirements while aligning with institution policies and workflow. This article serves as a comprehensive guide for neuroradiology fellowship PDs, providing direction and resources needed to lead a successful and compliant fellowship program.

在过去十年中，神经放射学专科培训项目主任的职责范围和所需投入的时间大幅增加。项目主任必须不断完善并记录一套完善、有效的课程体系，该体系要满足日益严格的认证要求，同时符合所在机构的政策和工作流程。本文为神经放射学专科培训项目主任提供了全面指南，为他们成功开展合规的专科培训项目提供指导和所需资源。

REF: Hagiwara M, Hu R, Bhatt AA, et al. Neuroradiology Fellowship Programs: A Comprehensive Guide for Neuroradiology Fellowship Program Directors. AJNR Am J Neuroradiol. 2025;46(8):1528-1533. Published 2025 Aug 1. doi:10.3174/ajnr.A8838 PMID: 40379459

Posterior Fossa Ring-Enhancing Lesions in the Adult Immunocompetent Host: Illustrative Cases, Systematic Review, and Proposed Diagnostic Algorithm

免疫功能正常成人的后颅窝环形强化病变：病例展示、系统评价及拟议的诊断算法

Posterior fossa ring-enhancing lesions (PFREL) in immunocompetent adults represent a diagnostic challenge. We conducted a retrospective institutional analysis combined with a systematic literature review (PRISMA 2020) to describe the etiological spectrum of PFREL and to develop a diagnostic algorithm. Among 116 cases reviewed, infectious causes were most common (52%), followed by tumoral (38%) and inflammatory (2%) etiologies. Headache was the most frequent symptom, and 36% of patients presented with multiple lesions. Reported outcomes varied, with complete symptom resolution in 36% of cases and a mortality rate of 16%. Based on clinical and radiological features, we proposed a diagnostic algorithm, which was validated on an independent cohort of 16 patients and provided correct classification in each case. This algorithm may support the diagnostic process in PFREL and help to guide further investigations and management.

免疫功能正常成年人的后颅窝环形强化病灶（PFREL）是诊断难题。我们进行了一项机构回顾性分析，并结合系统文献综述（遵循PRISMA 2020指南），以描述PFREL的病因谱并制定诊断算法。在回顾的116例病例中，感染性病因最为常见（52%），其次是肿瘤性病因（38%）和炎症性病因（2%）。头痛是最常见的症状，36%的患者存在多个病灶。报告的预后情况不一，36%的病例症状完全缓解，死亡率为16%。基于临床和影像学特征，我们提出了一种诊断算法，并在一个由16名患者组成的独立队列中进行了验证，该算法在每个病例中都能提供正确的分类。这种算法可能有助于PFREL的诊断过程，并有助于指导进一步的检查和治疗。

REF: Van Boxstael E, de Hennin A, Vigneul E, et al. Posterior Fossa Ring-Enhancing Lesions in the Adult Immunocompetent Host: Illustrative Cases, Systematic Review, and Proposed Diagnostic Algorithm. AJNR Am J Neuroradiol. 2025;46(8):1534-1541. Published 2025 Aug 1. doi:10.3174/ajnr.A8677 PMID: 39880690

Sex-Specific Association between Anatomic Variants of the Circle of Willis and Intracranial Aneurysms in Individuals with a Familial Predisposition

有家族易感性个体中 Willis 环解剖变异与颅内动脉瘤的性别特异性关联

First-degree relatives of patients with aneurysmal subarachnoid hemorrhage (aSAH) face elevated risks for intracranial aneurysm development and aSAH, which both occur more often in women. Anatomic variants of the circle of Willis (CoW) affect its hemodynamics and are associated with unruptured intracranial aneurysms (UIAs). It is unknown if these findings apply to patients with a familial predisposition for these conditions and if they are sex-specific. We, therefore, assessed if anatomic CoW variants are associated with intracranial aneurysms identified at screening in individuals with a familial predisposition and if these associations are sex-specific. Women with intracranial aneurysms identified at screening less frequently had a normal anterior part of the CoW compared with those without aneurysms. Additionally, individuals with aneurysms more often had anterior communicating artery hypoplasia or absence, which association was not sex-specific. These anatomic variations may enhance the effectiveness of screening for intracranial aneurysms.

动脉瘤性蛛网膜下腔出血（aSAH）患者的一级亲属发生颅内动脉瘤和aSAH的风险升高，且这两种情况在女性中更为常见。 Willis环（CoW）的解剖变异会影响其血流动力学，并且与未破裂颅内动脉瘤（UIA）相关。 目前尚不清楚这些发现是否适用于有这些疾病家族易感性的患者，以及是否存在性别特异性。 因此，我们评估了在有家族易感性的个体中，CoW解剖变异是否与筛查时发现的颅内动脉瘤相关，以及这些关联是否具有性别特异性。 与未发现动脉瘤的女性相比，筛查时发现颅内动脉瘤的女性CoW前部正常的情况较少。 此外，有动脉瘤的个体更常出现前交通动脉发育不全或缺失，这种关联无性别特异性。 这些解剖变异可能会提高颅内动脉瘤筛查的有效性。

REF: Nanninga MHA, van Strien DAM, Velthuis BK, et al. Sex-Specific Association between Anatomic Variants of the Circle of Willis and Intracranial Aneurysms in Individuals with a Familial Predisposition. AJNR Am J Neuroradiol. 2025;46(8):1542-1547. Published 2025 Aug 1. doi:10.3174/ajnr.A8690 PMID: 39909568

Impact of Previous Glycemic Control on High-Resolution MRI Plaque Characteristics and Stroke Mechanisms in Patients with Middle Cerebral Artery Atherosclerosis

既往血糖控制对大脑中动脉粥样硬化患者高分辨率磁共振成像斑块特征及卒中机制的影响

Although diabetes mellitus (DM) is a consistently documented risk factor for the plaque vulnerability, the effect of diabetes mellitus and glycemic control on the characteristics of intracranial plaques and stroke mechanism has yet to be explored. This study aimed to explore whether prestroke glycemic control is linked to plaque instability and could result in varying types and mechanisms of stroke. Poor glycemic control is independently linked to heightened plaque enhancement and a higher prevalence of complicated plaque. More large cortical/cortical-deep patterns were found, which may be associated with a small increase in artery-to-artery embolism and mixed mechanisms in such patients.

尽管糖尿病（DM）一直被认为是斑块易损性的危险因素，但糖尿病及血糖控制情况对颅内斑块特征和卒中机制的影响仍有待探索。本研究旨在探讨卒中前血糖控制情况是否与斑块不稳定性相关，以及是否会导致不同类型和机制的卒中。血糖控制不佳与斑块强化程度增加和复杂斑块患病率升高独立相关。研究发现，此类患者出现更多的大面积皮质/皮质 - 深部梗死模式，这可能与动脉 - 动脉栓塞和混合机制的轻微增加有关。

REF: Huang Q, Liu W, Liu L, et al. Impact of Previous Glycemic Control on High-Resolution MRI Plaque Characteristics and Stroke Mechanisms in Patients with Middle Cerebral Artery Atherosclerosis. AJNR Am J Neuroradiol. 2025;46(8):1548-1556. Published 2025 Aug 1. doi:10.3174/ajnr.A8721 PMID: 40675810

The Brush Sign Is Associated with a More Severe Oxygen Metabolic Impairment of the Ischemic Penumbra: An MRI-Based Study in Patients with Acute Stroke

毛刷征与缺血半暗带更严重的氧代谢损伤相关：一项基于急性脑卒中患者的磁共振成像研究

In acute stroke, the brush sign has been linked to an increased risk of hemorrhagic transformation. We aimed to assess the oxygen metabolic abnormalities occurring in patients with acute ischemic stroke (AIS) exhibiting the brush sign on admission MRI and its prognostic value at follow-up. The brush sign on admission MRI was associated with a more severe reduction in CMRO2 within the ischemic penumbra and poorer clinical outcomes at 3 months in patients with AIS treated with mechanical thrombectomy.

在急性卒中中，毛刷征与出血性转化风险增加有关。我们旨在评估急性缺血性卒中（AIS）患者入院磁共振成像（MRI）显示毛刷征时发生的氧代谢异常及其随访时的预后价值。对于接受机械取栓治疗的AIS患者，入院MRI上的毛刷征与缺血半暗带内脑氧代谢率（CMRO2）更严重降低以及3个月时较差的临床结局相关。

REF: Criton G, Hermier M, de Bourguignon C, et al. The Brush Sign Is Associated with a More Severe Oxygen Metabolic Impairment of the Ischemic Penumbra: An MRI-Based Study in Patients with Acute Stroke. AJNR Am J Neuroradiol. 2025;46(8):1557-1564. Published 2025 Aug 1. doi:10.3174/ajnr.A8723 PMID: 40744720

Corticospinal Tract Displacement: A Novel Imaging Marker for Arm Recovery in Patients with Acute Hypertensive Intracerebral Hemorrhage

皮质脊髓束移位：急性高血压性脑出血患者上肢功能恢复的一种新型影像学标志物

Brain parenchymal mass effect after acute intracerebral hemorrhage (ICH) causes neurologic deficits by displacing and or damaging the corticospinal tract (CST). The impact of corticospinal tract displacement (CSTD) on arm recovery and the influence of hematoma reversal on recovery are not well understood. We conducted a serial MRI study to explore these relationships. We present a quantitative surrogate imaging marker of CSTD and its association with arm recovery after ICH.

急性脑出血（ICH）后脑实质占位效应通过挤压和（或）损伤皮质脊髓束（CST）导致神经功能缺损。皮质脊髓束移位（CSTD）对上肢恢复的影响以及血肿逆转对恢复的影响尚不清楚。我们开展了一项系列磁共振成像研究，以探索这些关系。我们提出了一种定量的CSTD影像学替代标志物，并分析其与脑出血后上肢恢复的相关性。

REF: Savitz SI, Boren SB, Sitton CW, et al. Corticospinal Tract Displacement: A Novel Imaging Marker for Arm Recovery in Patients with Acute Hypertensive Intracerebral Hemorrhage. AJNR Am J Neuroradiol. 2025;46(8):1565-1572. Published 2025 Aug 1. doi:10.3174/ajnr.A8729 PMID: 40675812

The Cortical Vein Opacification Score Is Independently Associated with Good and Excellent Functional Outcomes at 90 Days in Patients with Minor Stroke with Anterior Circulation Large-Vessel Occlusion: A Multicenter Study

一项多中心研究：皮质静脉显影评分与前循环大血管闭塞性轻型卒中患者90天良好及极佳功能预后独立相关

There is currently no consensus on the most appropriate emergent treatment for patients with acute ischemic stroke secondary to large-vessel occlusion and minor stroke. These patients were excluded from prior randomized controlled trials assessing the efficacy of mechanical thrombectomy in large-vessel occlusion, making it challenging to determine the best treatment approach. Therefore, identifying markers that can predict functional outcomes would be invaluable for triaging these patients for mechanical thrombectomy. This study aimed to investigate pretreatment clinical and imaging markers and their association with functional outcomes at 90 days in patients with minor acute ischemic stroke secondary to large-vessel occlusion (AIS-LVO). Our analysis demonstrates that COVES is independently associated with good and excellent functional outcomes at 90 days in cases of minor AIS-LVO. Further prospective studies are needed to better understand the role of COVES in determining optimal management strategies for these patients.

目前，对于因大血管闭塞导致的急性缺血性中风且症状轻微的患者，最适宜的紧急治疗方案尚无共识。这些患者被排除在之前评估大血管闭塞机械取栓术疗效的随机对照试验之外，这使得确定最佳治疗方法颇具挑战性。因此，识别能够预测功能预后的标志物对于对这些患者进行机械取栓术分流将非常有价值。本研究旨在探讨大血管闭塞所致轻微急性缺血性中风（AIS - LVO）患者的治疗前临床和影像学标志物，以及它们与90天功能预后的关联。我们的分析表明，在轻微AIS - LVO病例中，COVES与90天良好和极佳的功能预后独立相关。需要进一步的前瞻性研究，以更好地了解COVES在确定这些患者最佳管理策略中的作用。

REF: Lakhani DA, Salim H, Balar AB, et al. The Cortical Vein Opacification Score Is Independently Associated with Good and Excellent Functional Outcomes at 90 Days in Patients with Minor Stroke with Anterior Circulation Large-Vessel Occlusion: A Multicenter Study. AJNR Am J Neuroradiol. 2025;46(8):1573-1578. Published 2025 Aug 1. doi:10.3174/ajnr.A8739 PMID: 40389269

Susceptibility Changes on Preoperative Acetazolamide-Loaded 7T MR Quantitative Susceptibility Mapping Predict Post–Carotid Endarterectomy Cerebral Hyperperfusion

术前乙酰唑胺负荷 7T 磁共振定量磁敏感成像的磁敏感变化可预测颈动脉内膜剥脱术后的脑高灌注

Post-carotid endarterectomy (CEA) cerebral hyperperfusion (CH) can cause intracerebral hemorrhage and cognitive decline. Alterations in susceptibility in response to acetazolamide (ACZ) on 7T MRI quantitative susceptibility mapping (QSM) detect elevated CBV occurring due to impaired cerebrovascular autoregulation. We explored preoperative relative susceptibility changes on 7T MRI QSM in response to ACZ and their ability to predict CH following CEA. Changes in susceptibility on preoperative 7T MRI QSM following ACZ administration predict CH following CEA. Patients with increased RSD5 on pre-CEA 7T MRI QSM following ACZ administration should undergo brain perfusion imaging immediately after surgery. Detection of CH on postoperative brain perfusion imaging warrants intensive blood pressure control.

颈动脉内膜切除术（CEA）后脑部过度灌注（CH）可导致脑出血和认知功能下降。7T磁共振定量磁敏感图（QSM）检测到的对乙酰唑胺（ACZ）的磁敏感变化，能发现因脑血管自动调节功能受损导致的脑血容量升高。我们探究了7T MRI QSM上术前对ACZ的相对磁敏感变化及其预测CEA后CH的能力。术前7T MRI QSM在使用ACZ后磁敏感的变化可预测CEA后的CH。CEA术前7T MRI QSM在使用ACZ后相对磁敏感差异5（RSD5）增加的患者，术后应立即进行脑灌注成像检查。术后脑灌注成像检测到CH时，需强化血压控制。

REF: Kimura K, Akamatsu Y, Fujimoto K, et al. Susceptibility Changes on Preoperative Acetazolamide-Loaded 7T MR Quantitative Susceptibility Mapping Predict Post-Carotid Endarterectomy Cerebral Hyperperfusion. AJNR Am J Neuroradiol. 2025;46(8):1579-1586. Published 2025 Aug 1. doi:10.3174/ajnr.A8692 PMID: 39909571