SWI Sequences Research Articles

Obstructive hydrocephalus due to developmental venous anomalies: a pediatric imaging case series.

Developmental venous anomalies are a rare cause of obstructive hydrocephalus in the pediatric population. In this study, we present the most extensive case series of DVA-induced obstructive hydrocephalus in the pediatric population. We thoroughly describe the imaging findings related to this uncommon entity and comprehensively discuss its clinical presentation and management strategies. The goal is to alert pediatric neuroradiologists to consider this rare condition in the differential diagnosis of hydrocephalus, particularly during prenatal screening or in pediatric cases. The electronic patient record systems of 2 tertiary care children's hospitals were reviewed to identify pediatric patients with confirmed DVAs leading to obstructive hydrocephalus. Age at diagnosis, gender, MRI findings (including location of the obstruction), clinical presentation, and symptoms were recorded. Data on treatment and follow-up imaging were also collected. The search yielded 5 cases of pediatric patients with DVA-induced obstructive hydrocephalus. The mean age at diagnosis of the DVA was 2.9 years (range: 0-7 years), and in two cases, ventriculomegaly was diagnosed in utero during prenatal cranial ultrasound screenings. In all patients, the DVA caused stenosis of the aqueduct of Sylvius, and one case presented with multiple DVAs. Although aqueductal stenosis caused by a DVA is rare, it is crucial to consider it in the differential diagnosis of hydrocephalus during prenatal screening or in the pediatric population. Brain MRI, especially post-contrast T1WI, and SWI sequences are particularly valuable for visualizing the typical "caput medusae" appearance of DVAs and detecting associated complications such as hemorrhages.

Symptomatic Cerebellar Thrombosed Developmental Venous Anomaly: A Case Report

Abstract Background With the rising prevalence of advanced neuroradiological imaging, detection of incidental developmental venous anomalies (DVAs) is more commonplace. DVAs are rarely symptomatic (<2%). Typically, symptoms arise due to flow-related complications or mechanical effects. Of particular concern is venous thrombosis, a frequent flow-related complication, which can cause venous ischemia or haemorrhage. Thus, early recognition and intervention is important. Methods We describe a case of a 54-year-old male, with background of hypertension, presenting three days after sudden onset headache, ataxia, and diplopia. Initial clinical examination revealed bidirectional horizontal gaze-evoked nystagmus, skew deviation, and decreased temperature sensation of the left face. Ophthalmological examination identified left inferior rectus limitation. Results Initial non-contrast CT brain identified hypoattenuation in the right pons, suggestive of sub-acute infarction. Secondary prevention was initiated. Subsequent MRI performed 5 days later revealed hyperattenuation on T2 and FLAIR in the pons, right middle cerebellar peduncle, and right cerebellar hemisphere without restricted diffusion. SWI sequences identified an abnormal venous structure in the right cerebellum, with increased signal within it, suggestive of thrombus. The patient was diagnosed with a thrombosed DVA with associated venous oedema. Symptoms had resolved on dual antiplatelet therapy, without anticoagulation. Conclusion This case highlights the potential for DVAs, generally considered a benign entity, to become symptomatic with associated parenchymal damage and a rare, but important, stroke mimic. Moreover, it underscores the pivotal role of MRI imaging; while a CT scan might have led to the assumption of a subacute infarct, MR imaging led to a complete re-evaluation of the diagnosis in this case.

Reversible leukoencephalopathy with seizures: a case of severe high-altitude cerebral edema

BackgroundAcute high-altitude illness (AHAI) refers to a series of syndromes including acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE). Among these, HACE is a severe and potentially life-threatening condition that can occur when individuals ascend to high altitudes. It is often characterized by ataxia, confusion, and altered mental status. Without appropriate treatment, HACE can rapidly progress to coma, but seizures are infrequent in occurrence.Case presentationHere, we report a severe HACE patient with coma and status epilepticus. The patient is a 23-year-old male who was visiting Lhasa for the first time. He initially experienced headaches and dizziness on the first day, and then he was found in coma with limb convulsions on the next day. Immediate medical attention was sought, and brain CT and MRI scans showed reversible white matter lesions, especially in the corpus callosum and subcortical white matter. Although the lesions disappeared on T1 and T2 sequences, microbleeds were observed on the SWI sequence. After treatment with tracheal intubation, glucocorticoids and hyperbaric oxygen, the cerebral edema has resolved and the clinical symptoms improved, the patient has no seizures anymore.ConclusionsHACE typically follows AMS and poses a significant risk to life. Clinical manifestations mainly include ataxia, alterations of behavior, and impaired consciousness, with severe cases progressing to coma. Seizures, though rarely observed, may occur. Imaging shows reversible white matter lesions, with microbleeds being a significant and persistent imaging marker over time. Administration of glucocorticoids plays a crucial role in treatment. Despite experiencing seizures, this patient did not experienced any further episodes once his condition improved.

Approaches to supratentorial brain tumours in children.

The differential diagnosis of supratentorial brain tumours in children can be challenging, especially considering the recent changes to the WHO classification of CNS tumours published in 2021. Many new tumour types have been proposed which frequently present in children and young adults and their imaging features are currently being described by the neuroradiology community.The purpose of this article is to provide guidance to residents and fellows new to the field of paediatric neuroradiology on how to evaluate an MRI of a patient with a newly diagnosed supratentorial tumour. Six different approaches are discussed including: 1. Tumour types, briefly discussing the main changes to the recent WHO classification of CNS tumours, 2. Patient age and its influence on incidence rates of specific tumour types, 3. Growth patterns, 4. Tumour location and how defining the correct location helps in narrowing down the differential diagnoses and 5. Imaging features of the tumour on DWI, SWI, FLAIR and post contrast sequences.

IMG-27. ASSESSMENT OF VARIABILITY OF PEDIATRIC BRAIN TUMOR IMAGING PROTOCOLS ACROSS INSTITUTIONS: ARE WE FOLLOWING RECOMMENDATIONS?

Abstract BACKGROUND Evaluating pediatric brain tumors requires imaging children with tailored MRI protocols. Considerable variation in pediatric brain tumor imaging protocols exist across institutions, which can cause inaccuracies in staging. Although recently consensus guidelines for pediatric brain tumor imaging protocols have been established, adherence to these guidelines across institutions is unknown. Institutions may perceive guidelines as applicable for research purposes rather than routine clinical practice. We aim to explore variability in pediatric brain tumor imaging protocols across institutions and determine the factors influencing guideline divergence. METHODS AND METHODOLOGY Faculty at institutions routinely imaging pediatric patients with brain tumors were invited to share brain tumor MRI protocols and complete a structured survey. The survey included multiple choice and open-ended queries concerning practice type, the presence of an institutional imaging protocol for pediatric brain tumors and if the protocol was based on specific consensus recommendations. We assessed if protocols included the 7 minimum recommended MRI sequences by the Children’s Oncology Group (COG) guidelines, including slice thickness and gap. RESULTS Twenty emails were sent and responses were received from 12 institutions (the data collection is still ongoing). 2 institutions did not have dedicated protocols for pediatric brain tumors. On average, institutions had 5.7 out of the 7 minimum COG-recommended sequences. All 10 institutions included 3D T1 IR-GRE/TSE, DWI or DTI, and SWI sequences in their protocols. 9 (90%) included post-contrast 3D T1 IR-GRE/TSE, 7 (70%) included T2 TSE/FSE, 7 (70%) included either 3D T2 FLAIR or T2 FLAIR TSE/FSE, and 4 (40%) included T1/TSE/FSE. Across all sequences in all protocols, adherence to recommended imaging parameters was 87% for plane, 71% for slice thickness, and 85% for gap. CONCLUSION Significant variability in pediatric brain tumor imaging protocols exists across institutions Standardizing imaging protocols through collaboration is vital in ensuring uniformity in care.

The role of SWI sequence during the preoperative targeting of the subthalamic nucleus for deep brain stimulation in Parkinson's disease: A retrospective cohort study

The role of SWI sequence during the preoperative targeting of the subthalamic nucleus for deep brain stimulation in Parkinson's disease: A retrospective cohort study

Enhancing Nigrosome-1 Sign Identification via Interpretable AI using True Susceptibility Weighted Imaging.

Nigrosome 1 (N1), the largest nigrosome region in the ventrolateral area of the substantia nigra pars compacta, is identifiable by the "N1 sign" in long echo time gradient echo MRI. The N1 sign's absence is a vital Parkinson's disease (PD) diagnostic marker. However, it is challenging to visualize and assess the N1 sign in clinical practice. To automatically detect the presence or absence of the N1 sign from true susceptibility weighted imaging by using deep-learning method. Prospective. 453 subjects, including 225 PD patients, 120 healthy controls (HCs), and 108 patients with other movement disorders, were prospectively recruited including 227 males and 226 females. They were divided into training, validation, and test cohorts of 289, 73, and 91 cases, respectively. 3D gradient echo SWI sequence at 3T; 3D multiecho strategically acquired gradient echo imaging at 3T; NM-sensitive 3D gradient echo sequence with MTC pulse at 3T. A neuroradiologist with 5 years of experience manually delineated substantia nigra regions. Two raters with 2 and 36 years of experience assessed the N1 sign on true susceptibility weighted imaging (tSWI), QSM with high-pass filter, and magnitude data combined with MTC data. We proposed NINet, a neural model, for automatic N1 sign identification in tSWI images. We compared the performance of NINet to the subjective reference standard using Receiver Operating Characteristic analyses, and a decision curve analysis assessed identification accuracy. NINet achieved an area under the curve (AUC) of 0.87 (CI: 0.76-0.89) in N1 sign identification, surpassing other models and neuroradiologists. NINet localized the putative N1 sign within tSWI images with 67.3% accuracy. Our proposed NINet model's capability to determine the presence or absence of the N1 sign, along with its localization, holds promise for enhancing diagnostic accuracy when evaluating PD using MR images. 2 TECHNICAL EFFICACY: Stage 1.

An ultra‐fast MRI protocol in dementia enabled by Wave‐CAIPI

AbstractBackgroundStructural brain imaging is essential for the diagnostic workup in dementia and for safety monitoring of disease modifying therapies. MRI has several advantages over other imaging techniques, but its use is limited by cost and availability. Reducing acquisition time holds the potential for its democratisation. We developed a prototype ultra‐fast MRI protocol based on an optimised 3D parallel imaging approach. Here we present the finalised version, developed using a qualitative and quantitative approach to optimisation.MethodIn this ongoing real‐world study, participants are sequentially recruited from the cognitive disorders' clinics of a tertiary centre. Patients due to have a standard 3T MRI scan as part of their diagnostic pathway are eligible. The standard‐of‐care protocol includes T1w, T2w, FLAIR and T2*/SWI sequences [scan time ∼18mins]. The prototype rapid protocol utilises Siemens work‐in‐progress 3D Wave‐CAIPI (Controlled Aliasing in Parallel Imaging) sequences, enabling a reduction in scan time of more than 60% (table 1). For qualitative analysis, scans (of 9 individuals) were reviewed by six raters and assessed side‐by‐side against the gold‐standard scan for diagnostic utility. For a quantitative analysis, volumes were calculated from T1w scans using the default cortical reconstruction and volumetric segmentation pipeline in FreeSurfer 7.3.2. Key volumes (e.g., deep grey matter, cortical grey matter, white matter) for each participant were compared between the two protocols. Independent visual QC was performed on T1w datasets by an experienced clinical trials team.ResultSide‐by‐side visual assessment results of 9 participants is shown in figure 1. For all sequences bar FLAIR, raters scored the ultra‐fast sequences of comparable image quality in at least 67% of cases. For quantitative analysis, 10 T1w sequence pairs were reviewed, with 1 clinical scan failing QC due to motion. Bland‐Altman analyses (figure 2.) comparing volumes between the clinical and ultra‐fast sequences show little bias.ConclusionOur preliminary results demonstrate that for most contrasts the ultra‐fast sequences are diagnostically non‐inferior and quantitatively equivalent to the clinical protocol both for diagnosis and for safety monitoring.

Longitudinal MR imaging after unilateral MR-guided focused ultrasound thalamotomy: clinical and radiological correlation.

Magnetic-resonance-guided focused ultrasound (MRgFUS) thalamotomy uses multiple converging high-energy ultrasonic beams to produce thermal lesions in the thalamus. Early postoperative MR imaging demonstrates the location and extent of the lesion, but there is no consensus on the utility or frequency of postoperative imaging. We aimed to evaluate the evolution of MRgFUS lesions and describe the incidence, predictors, and clinical effects of lesion persistence in a large patient cohort. A total of 215 unilateral MRgFUS thalamotomy procedures for essential tremor (ET) by a single surgeon were retrospectively analyzed. All patients had MR imaging 1 day postoperatively; 106 had imaging at 3 months and 32 had imaging at 1 year. Thin cut (2 mm) axial and coronal T2-weighted MRIs at these timepoints were analyzed visually on a binary scale for lesion presence and when visible, lesion volumes were measured. SWI and DWI sequences were also analyzed when available. Clinical outcomes including tremor scores and side effects were recorded at these same time points. We analyzed if patient characteristics (age, skull density ratio), preoperative tremor score, and sonication parameters influenced lesion evolution and if imaging characteristics correlated with clinical outcomes. Visible lesions were present in all patients 1 day post- MRgFUS and measured 307.4 ± 128.7 mm3. At 3 months, residual lesions (excluding patients where lesions were not visible) were 83.6% smaller and detectable in only 54.7% of patients (n = 58). At 1 year, residual lesions were detected in 50.0% of patients (n = 16) and were 90.7% smaller than 24 h and 46.5% smaller than 3 months. Lesions were more frequently visible on SWI (100%, n = 17), DWI (n = 38, 97.4%) and ADC (n = 36, 92.3%). At 3 months, fewer treatment sonications, higher maximum power, and greater distance between individual sonications led to larger lesion volumes. Volume at 24 h did not predict if a lesion was visible later. Lesion visibility at 3 months predicted sensory side effects but was not correlated with tremor outcomes. Overall, lesions are visible on T2-weighted MRI in about half of patients at both 3 months and 1 year post-MRgFUS thalamotomy. Certain sonication parameters significantly predicted persistent volume, but residual lesions did not correlate with tremor outcomes.

P05.02.A PRELIMINARY FINDINGS FROM THE MRI QUALITY ASSURANCE PROGRAMME FOR THE PROSPECTIVE MULTI-SITE AUSTRALIAN FIG ([FET-PET IN GLIOBLASTOMA) TROG 18.06 STUDY

Abstract BACKGROUND The O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) in Glioblastoma (FIG) study is a prospective study evaluating the management impact of FET-PET imaging in up to 210 newly diagnosed adult glioblastoma patients across 10 Australian sites. Patients undergo contrast MRI and FET-PET at 3 timepoints: pre-chemoradiotherapy (CRT), one-month post-CRT and at suspected progression. MRI QA programme components, approach and integrated workflows are described here. MATERIAL AND METHODS The FIG MRI protocol comprised 3D-T1, 3D-FLAIR, Axial 2D DWI (including derived ADC map), DCE (including T1 mapping), DSC, Axial T2 and 3D T1-post-contrast (T1C) sequences, with SWI and 3D DIR sequences optional. QA components included data acquisition quality and completeness (standard and advanced), motion artefact, low contrast to noise or signal to noise, series description and susceptibility artifacts. Suitability of T1/T1C using modified RANO (mRANO) criteria was assessed. An optimised workflow involved site upload from local PACS systems to centralised database via TROG Central Quality Management System (CQMS) platform and collation into a central imaging database utilising MIM software. The MRI QA workflow encompassed automated anonymisation of DICOM data, data completeness and reconstruction evaluation, then review by two expert neuroimaging analysts. Sites received feedback with request for resubmission where required. RESULTS Between December 2021 and February 2023, MRI data in 74 patients across 9 sites with median of 6 patients (range 2-17) per site was submitted. A total of 141 MRI datasets across all timepoints were collected (per site range:4-35, median:13), with 43 imaging time-points selected for QA (per site range:3-12, median: 4). Importantly, 41/43 (95%) of initial datasets were deemed suitable for mRANO assessment, but only 13/43 (30%) were suitable for advanced MRI analysis. Very few datasets had motion or susceptibility artifacts, low contrast to noise or signal to noise, or incorrect series description. Technical issues identified included incomplete data (DCE - missing T1 maps, DWI - missing ADC maps), incorrect sequence reconstruction (DCE split series and Axial/Sagittal/Coronal reformats for 3D images) and lack of non-mandatory SWI sequences. Feedback to sites resulted in improvements in DCE sequence acquisition from split series in 11/45 (24%) to preferred single series in 18/24 (75%) and similar increases in T1 maps completeness from 7/19 (37%) to 7/7 (100%). CONCLUSION Despite challenges in multisite workflow and substantial multi-modality site and central data management, a robust MRI QA program has confirmed 95% compliance for mRANO assessment. Site specific feedback resulted in increased compliance with advanced MRI sequences to enable detailed future analysis.

Prevalence and risk factors for cerebral microbleeds in elderly Chinese patients with arteriosclerotic cardiovascular diseases: A single-center study

ObjectivesPeople with arteriosclerotic cardiovascular diseases (ASCVD) frequently use antithrombotic agents and statins. The objective of the study was to explore the prevalence and risk factors of cerebral microbleeds (CMBs) in elderly (≥ 65 years old) Chinese people with ASCVD. Materials and methodsWe prospectively included 755 eligible participants with complete MRI data, and CMBs were discerned on the SWI sequence. Multivariate logistic regression was performed to analyze risk factors associated with CMBs. ResultsThe average age was 74.9 ± 9.5 years, and the prevalence of CMBs was 37.9% (286/755). Of those with CMBs, 65.0% (186/286) had strictly lobar CMBs, 35.0% (100/286) had deep or infratentorial CMBs with or without lobar CMBs. We divided CMBs into two groups according to their locations, lobar CMBs group (strictly lobar CMBs) and deep CMBs group (with or without lobar CMBs). Age per 10 years (odds ratio (OR) 1.42, 95% confidence interval (CI) 1.17–1.72, p < 0.001), statin use (OR 1.54, 95% CI 1.05–2.26, p = 0.03), and lacunes (OR 1.70, 95% CI 1.09–2.68, p = 0.02) were associated with any CMBs. Age per 10 years (OR 1.33, 95% CI 1.10–1.63, p < 0.001), statin use (OR 1.67, 95% CI 1.12–2.50, p = 0.01), and white matter hyperintensities (OR 1.71, 95% CI 1.17–2.51, p < 0.01) were associated with lobar CMBs. Only lacunes were associated with deep CMBs (OR 3.29, 95% CI 1.85–5.87, p < 0.001). ConclusionsIn elderly people with risk factors of ASCVD, antithrombotic drug use was not associated with any CMBs, lobar CMBs, or deep CMBs. Statin use was correlated with lobar CMBs but not deep CMBs.

Poster 151: Femoral Cartilage T2* Relaxation Times Correlate With Inflammatory Biomarker MCP-1 Levels In Serum, But Not Synovial Fluid, After ACL Injury In A Skeletally Immature Porcine Model

Poster 151: Femoral Cartilage T2* Relaxation Times Correlate With Inflammatory Biomarker MCP-1 Levels In Serum, But Not Synovial Fluid, After ACL Injury In A Skeletally Immature Porcine Model

Clinical, imaging and genetic profile of twenty-four patients with pantothenate kinase-associated neurodegeneration (PKAN)- A single centre study from India

IntroductionPantothenate kinase-associated neurodegeneration (PKAN) is the most common “Neurodegeneration with Brain Iron Accumulation” disorder. This study aimed to study the clinical, radiological and genetic profiling of a large cohort of patients with PKAN. MethodsThis is an ambispective hospital-based single centre study conducted at a tertiary care centre from India. After tabulating the clinical details, appropriate rating scales were applied followed by magnetic resonance imaging brain and exome sequencing. The segregation of the causal variants in the families were analysed using Sanger sequencing. ResultsTwenty-four patients (14 males) with a median age at initial examination of 13 years (range: 4–54 years) and age at onset of 8 years (range: 0.5–40 years) were identified. Almost two-thirds (62%) had onset before 10 years. Difficulty walking was the most common presenting symptom (41.6%) and dystonia was the most common extrapyramidal phenomenology (100%) followed by parkinsonism (54.2%). Retinitis pigmentosa was present in 37.5% patients. MRI showed hypo intensity on T2 and SWI sequences in globus pallidus (100%), substantia nigra (70.8%) and red nucleus (12.5%). Eye-of-the-tiger sign was present in 95.8%. Biallelic variants in PANK2 gene was identified in all 20 patients who underwent genetic testing. Among the 18 unique variants identified in these 20 patients 10 were novel. Sanger sequencing confirmed the segregation of the mutation in the available family members. ConclusionsWide range of age at onset was noted. Dystonia at presentation, pathognomonic eye-of-tiger sign, and disease-causing variants in PANK2 gene were identified in nearly all patients. Ten novel variants were identified expanding the genotypic spectrum of PKAN.

Correlation between insulin resistance and cerebral microbleeds among Chinese patients with cerebral small vessel disease

Background and objectivesInsulin resistance (IR) plays an important role in the pathogenesis of cerebral small vessel disease (CSVD); however, little is known about the relationship between IR and the incidence of cerebral microbleeds (CMBs) in Asian populations. The aim of this study is to investigate the relationship between CMBs and IR in Chinese patients with CSVD. MethodsThis retrospective study included 240 patients with CSVD. Patients were categorized by the homeostatic model assessment of insulin resistance (HOMA-IR): Quartile 1 (≤1.26), Quartile 2 (1.27–1.92), Quartile 3 (1.93–2.89), and Quartile 4 (>2.89). The medical record of each patient was reviewed, and demographic, clinical and laboratory information was abstracted. All patients completed an MRI scan, and CMBs were defined as round or ovoid hypointense lesions on SWI sequence. ResultsCMBs were present in 82 (34.17%) of the 240 patients that were included in the study (mean age, 71 years; male, 54.89%). After adjustment for potential confounding variables, insulin resistance was associated with the presence of CMBs (adjusted odds ratio 2.298, 95% confidence interval 1.017–5.194 for Q4:Q1; P = 0.046). According to receiver operating characteristic analysis, the best discriminating factor for CMBs was a HOMA-IR level ≥2.215 (area under the curve 0.595; sensitivity 51.2%; specificity 65.2%). ConclusionsIR is significantly associated with the presence of CMBs, suggesting the potential role of IR as a predictive marker for CMBs in patients with CSVD.

Deep learning based detection of enlarged perivascular spaces on brain MRI

Deep learning has been demonstrated effective in many neuroimaging applications. However, in many scenarios, the number of imaging sequences capturing information related to small vessel disease lesions is insufficient to support data-driven techniques. Additionally, cohort-based studies may not always have the optimal or essential imaging sequences for accurate lesion detection. Therefore, it is necessary to determine which imaging sequences are crucial for precise detection. This study introduces a deep learning framework to detect enlarged perivascular spaces (ePVS) and aims to find the optimal combination of MRI sequences for deep learning-based quantification. We implemented an effective lightweight U-Net adapted for ePVS detection and comprehensively investigated different combinations of information from SWI, FLAIR, T1-weighted (T1w), and T2-weighted (T2w) MRI sequences. The experimental results showed that T2w MRI is the most important for accurate ePVS detection, and the incorporation of SWI, FLAIR and T1w MRI in the deep neural network had minor improvements in accuracy and resulted in the highest sensitivity and precision (sensitivity = 0.82, precision = 0.83). The proposed method achieved comparable accuracy at a minimal time cost compared to manual reading. The proposed automated pipeline enables robust and time-efficient readings of ePVS from MR scans and demonstrates the importance of T2w MRI for ePVS detection and the potential benefits of using multimodal images. Furthermore, the model provides whole-brain maps of ePVS, enabling a better understanding of their clinical correlates compared to the clinical rating methods within only a couple of brain regions.

基于SWI序列的支持向量机模型鉴别高级别胶质瘤与脑内单发转移瘤

基于SWI序列的支持向量机模型鉴别高级别胶质瘤与脑内单发转移瘤

Ischemic stroke can have a T1w hyperintense appearance in absence of intralesional hemorrhage.

Magnetic resonance imaging (MRI) signal changes associated with ischemic stroke are typically described as T2w and FLAIR hyperintense, and T1w isointense lesions. Intralesional T1w hyperintensity is generally attributed to either a hemorrhagic stroke, or an ischemic stroke with hemorrhagic transition, and has an associated signal void on gradient echo (GE) sequences. Cases of ischemic stroke with T1w hyperintense signal in absence of associated signal void on GE sequences have been sporadically demonstrated in human stroke patients, as well as in dogs with experimentally induced ischemia of the middle cerebral artery. This multicenter retrospective descriptive study investigates the presence of T1w hyperintensity in canine stroke without associated signal void on GE sequences. High field (1.5 Tesla) MRI studies of 12 dogs with clinical presentation, MRI features, and cerebrospinal fluid results suggestive of non-hemorrhagic stroke were assessed. The time between the observed onset of clinical signs and MRI assessment was recorded. All 12 patients had an intralesional T1w hyperintense signal compared to gray and white matter, and absence of signal void on T2*w GE or SWI sequences. Intralesional T1w hyperintensities were either homogenously distributed throughout the entire lesion (6/12) or had a rim-like peripheral distribution (6/12). The mean time between the recorded onset of clinical signs and MRI assessment was 3 days; however, the age range of lesions with T1w hyperintense signal observed was 1–21days, suggesting that such signal intensities can be observed in acute, subacute, or chronic stages of ischemic stroke. Follow-up was recorded for 7/12 cases, all of which showed evidence of neurological improvement while in hospital, and survived to discharge. Correlation of the age and MRI appearance of lesions in this study with similar lesions observed in human and experimental studies suggests that these T1w hyperintensities are likely caused by partial tissue infarction or selective neuronal necrosis, providing an alternative differential for these T1w hyperintensities observed.

Primary CNS vasculitis (PCNSV): a cohort study

Primary CNS Vasculitis (PCNSV) is a rare inflammatory disorder affecting the blood vessels of the central nervous system. Patients present with a combination of headaches, seizures, and focal neurological deficits. There is usually a diagnostic delay. Treatment is based on observational studies and expert opinion. Our objective was to identify clinical, laboratory, neuroimaging, pathologic or management-related associations with 2 year outcome in patients with primary CNS vasculitis. We conducted a cohort study at a single tertiary care referral centre of prospectively (2018-2019) and retrospectively (2010-2018) identified individuals with primary CNS vasculitis (diagnosis was proven by either brain biopsy or cerebral digital subtraction angiography). Clinical, imaging and histopathologic findings, treatment, and functional outcomes were recorded. Univariate and stepwise multiple logistic regression were applied. P-value<0.05 was considered statistically significant. The main outcome measures were documentation of clinical improvement or worsening (defined by mRS scores) and identification of independent predictors of good functional outcome (mRS 0-2) at 2 years. We enrolled eighty-two biopsy and/or angiographically proven PCNSV cases. The median age at presentation was 34 years with a male predilection and a median diagnostic delay of 23 months. Most patients presented with seizures (70.7%). All patients had haemorrhages on MRI. Histologically lymphocytic subtype was the commonest. Corticosteroids with cyclophosphamide was the commonest medication used. The median mRS at follow-up of 2 years was 2 (0-3), and 65.2% of patients achieved a good functional outcome. Myelitis and longer duration of illness before diagnosis were associated with poorer outcomes. The presence of hemorrhages on SWI sequence of MRI might be a sensitive imaging marker. Treatment with steroids and another immunosuppressant probably reduced relapse rates in our cohort. We have described the third largest PCNSV cohort and multi-centre randomised controlled trials are required to study the relative efficacy of various immunosuppressants.Study registration: CTRI/2018/03/012721.

Can MRI differentiate between ring-enhancing gliomas and intra-axial abscesses?

Gliomas of the brain may appear as expansile ring-enhancing masses in MRI studies, mimicking the appearance of intra-axial abscesses. The aims of this study were to compare the MRI features of ring-enhancing gliomas and intra-axial brain abscesses in dogs and cats and to identify the characteristics that might help differentiate them. For this multicenter, retrospective, and observational study, the inclusion criteria were as follows: (a) a definitive diagnosis of glioma or abscess based on cytological or histopathological examination following CSF collection or surgical biopsy/necropsy, respectively; (b) MRI study performed with a high- or low-field MRI scanner, including a same plane T1W pre- and postcontrast, a T2W and a T2 FLAIR sequence in at least one plane. If available, delayed T1W postcontrast, T2*W GE, DWI/ADC, and SWI sequences were also evaluated. Sixteen patients were diagnosed with ring-enhancing gliomas, and 15 were diagnosed with intra-axial abscesses. A homogenous signal on T1W (P=0.049) and T2W (P=0.042) sequences, a T2W (P=0.005) or T2*W GE (P=0.046) peripheral hypointense halo, and an even enhancing capsule (P=0.002) were significantly associated with brain abscesses. A progressive central enhancement on delayed T1W postcontrast sequences was correlated with ring-enhancing gliomas (P=0.009). The combination of the following features was suggestive of brain abscess: homogeneous T1W or T2W signal intensity, a T2W or T2*W GE peripheral hypointense halo and an evenly enhancing capsule. Central progression of enhancement on delayed T1W postcontrast sequences was suggestive of glioma.

Vascular Lesions and Brain Atrophy in Alzheimer's, Vascular and Mixed Dementia: An Optimized 3T MRI Protocol Reveals Distinctive Radiological Profiles.

Vascular lesions may be a common finding also in Alzheimer's dementia, but their role on cognitive status is uncertain. The study aims to investigate their distribution in patients with Alzheimer's, vascular or mixed dementia and detect any distinctive neuroradiological profiles. Seventy-six subjects received a diagnosis of Alzheimer's (AD=32), vascular (VD=26) and mixed (MD=18) dementia. Three independent raters assessed the brain images acquired with an optimized 3T MRI protocol (including (3D FLAIR, T1, SWI, and 2D coronal T2 sequences) using semiquantitative scales for vascular lesions (periventricular lesions (PVL), deep white matter lesions (DWML), deep grey matter lesions (DGML), enlarged perivascular spaces (PVS), and microbleeds (MB)) and brain atrophy (medial temporal atrophy (MTA), posterior atrophy (PA), global cortical atrophy- frontal (GCA-F) and Evans' index). Raters reached a good-to-excellent agreement for all scales (ICC ranging from 0.78-0.96). A greater number of PVL (p<0.001), DWML (p<0.001), DGML (p=0.010), and PVS (p=0.001) was observed in VD compared to AD, while MD showed a significant greater number of PVL (p=0.001), DWML (p=0.002), DGML (p=0.018), and deep and juxtacortical MB (p=0.006 and p<0.001, respectively). Comparing VD and MD, VD showed a higher number of PVS in basal ganglia and centrum semiovale (p=0.040), while MD showed more deep and juxtacortical MB (p=0.042 and p=0.022, respectively). No significant difference was observed in scores of cortical atrophy scales and Evans' index among the three groups. The proposed MRI protocol represents a useful advancement in the diagnostic assessment of patients with cognitive impairment by more accurately detecting vascular lesions, mainly microbleeds, without a significant increase in time and resource expenditure. Our findings confirm that white and grey matter lesions predominate in vascular and mixed dementia, whereas deep and juxtacortical microbleeds predominate in mixed dementia, suggesting that cerebral amyloid angiopathy could be the main underlying pathology.