Susceptibility-weighted Imaging Research Articles

Author Response: Cerebral Microbleeds and Treatment Effect of Intravenous Thrombolysis in Acute Stroke: An Analysis of the WAKE-UP Randomized Clinical Trial.

We are grateful for the interest in our article on the treatment effect of alteplase in acute ischemic stroke patients with preexisting cerebral microbleeds (CMBs).1 The readers point out that new lesions are observed on susceptibility-weighted imaging (SWI) in patients with artificial heart valves that meet the imaging criteria of CMBs and suggest that these lesions should be differentiated from CMBs associated with small vessel disease to better identify patients with an increased bleeding risk.2 Of interest, a previous study showed that new CMBs occurring in acute ischemic stroke patients after receiving IV thrombolysis (IVT) were indeed associated with an increased risk of IVT-related hemorrhagic complications.3 On the other hand, new CMBs were not associated with an increased risk of bleeding in patients undergoing cardiac surgery.2,4 However, IVT may constitute a different bleeding risk than cardiopulmonary bypass and extracorporeal membrane oxygenation, or a prolonged intensive care unit stay. The question of whether CMBs in patients with artificial heart valves represent a different pathophysiologic entity with a different bleeding risk merits further research and would profit from histopathology studies and observational studies in stroke and nonstroke cohorts with long-term follow-up.

Susceptibility-Weighted MRI as an Imaging Marker for Reperfusion Injury in Acute Ischemic Stroke Following Mechanical Thrombectomy.

Following endovascular intervention for stroke, hyperattenuated areas are common in brain parenchyma and it is difficult to differentiate on non-contrast CT whether it is contrast staining or reperfusion hemorrhage. Differentiation between contrast staining from reperfusion hemorrhage is of paramount importance for early initiation of antiplatelets and/or anticoagulants to prevent reocclusion of vessel. This study demonstrates signal characteristics of contrast-staining and reperfusion hemorrhage on susceptibility weighted MRI and its role to differentiate between two. Between July 2017 to March 2019, 36 patients who presented with acute ischemic stroke due to large vessel occlusion underwent mechanical thrombectomy. Low-osmolar non-ionic (Iopromide 300 mg/L) iodinated contrast was used in all patients who underwent endovascular intervention. All patients underwent noncontrast CT brain and SWI on 3T MRI within 30 minutes of endovascular intervention. MRI was evaluated by two neuroradiologists. Reperfusion hemorrhage was defined as ECASS criteria II. Symptomatic ICH was defined as hemorrhagic transformation temporally related to a negative shift in NIHSS score >/=4. Out of 36 patients, 15 had hyperattenuated areas in brain on NCCT. Out of 15, 13 patients had blooming on SWI, suggestive of bleed. Two patients had no blooming on SWI, suggestive of contrast staining. Two patients didnot show any hyperdensity on NCCT but blooming on SWI, suggestive of bleed. All patients with hyperdensity on NCCT secondary to bleed showed blooming on SWI whereas those with contrast staining didnot show any signal changes on SWI. Thus, it is possible to differentiate reperfusion hemorrhage from contrast staining using SWI MRI. The significance of SWI in normal CT may be low where a small bleed maynot have any clinical significance.

Cerebral Microbleeds Detected by Susceptibility-Weighted Imaging in a Patient with Idiopathic Normal Pressure Hydrocephalus

Cerebral Microbleeds Detected by Susceptibility-Weighted Imaging in a Patient with Idiopathic Normal Pressure Hydrocephalus

Relative contribution of susceptibility weighted imaging, compared to conventional MRI, in the detection of common bile-duct calculi.

PURPOSE We aimed to evaluate the relative contribution of susceptibility weighted imaging (SWI) in the detection of common bile-duct (CBD) stones in comparison to the conventional MRI protocol containing magnetic resonance cholangiopancreatography (MRCP), balanced turbo field echo (BTFE), and T2-weighted spin-echo imaging techniques. METHODS MRI data containing MRCP, BTFE, T2-weighted imaging, and abdominal SWI were independently evaluated by 2 sets of experienced radiologists in 44 patients with confirmed CBD stones. Endoscopic retrograde cholangiopancreatography, and endoscopic ultrasound where available, was used as the reference gold standard. Evaluation was performed for the visualization of CBD stones in each of the MRI techniques. Relative contribution of SWI was classified into one of four categories for each case: (1) no contribution to CBD stone visualization; (2) same as conventional techniques; (3) improved diagnostic confidence; and (4) critical for diagnosis. Stone size was also assessed. RESULTS Inter-rater agreement coefficient for CBD stone visualization was found to be "good" in MRCP (0.77), "very good" in SWI (0.94) and BTFE (0.84), and moderate in T2-weighted imaging (0.54). CBD stones were visualized with SWI in 86.4% and 82%, with MRCP in 70.5% and 70.5% cases, with BTFE in 73% and 61.4% cases, with T2-weighted imaging in 45.5% and 52.3% cases by reviewers 1 and 2, respectively. SWI did not contribute to CBD stone visualization in 2.3% (1/44); was the same as conventional techniques in 31.8% (14/44) cases; improved diagnostic confidence in 34.1%; and was critical for diagnosis in 20.5% cases. CONCLUSION SWI has the potential to serve as a strong adjunct to conventional MRI protocols used for CBD stone evaluation with very small scan-time penalty.

Susceptibility Weighted Imaging (SWI) and Gre T2* Imaging in the Diagnosis of Cerebral Cavernous Malformations: Our 3 Tesla Experience

Bu çalışma serebral kavernöz malformasyonların (SKM), SWI ve Gradient eko T2* (GRE T2*) görüntülerde saptanabilirliği ve lezyonların her iki sekanstaki boyutsal farklılıklarının karşılaştırılmasıdır. Çalışmamıza yaşları 14 ile 80 (42.4±17.58) arasında değişen toplam 57 SKM'li hasta (32 erkek, 25 kadın) dahil edildi. Kranial MR görüntülemede, rutin sekanslara ek olarak SWI ve GRE T2* görüntüleme yapıldı. SKM lezyonlarının sayısı, boyutu ve alınan sekansta görülebilirliği açısından retrospektif olarak tekrar değerlendirildi. SWI görüntülemede saptanmış SKM sayısı (n=97), GRE T2* görüntülerde saptananlara (n=69) göre yüksekti. Lezyonların medyan (min-max) boyutu, SWI görüntülerde 7.9 (3.7-45) mm, GRE T2* görüntülerde 7.7 (3.6-42) mm olup aradaki fark istatistiksel olarak anlamlıydı (p<0.001). Ayrıca çalışmamızda 7 olguda SKM’ye eşlik eden gelişimsel venöz anomali ve 4 olguda eşlik eden fokal tip yüzeyel siderozis saptandı. SKM’ye eşlik eden fokal tip yüzeyel siderozis bulgusu SWI görüntülemede daha keskin ve ayrıntılı izlendi. SKM düşünülen olgularda tanısal üstünlüğü nedeni ile rutin kranial MR görüntülemeye SWI sekansı eklenmesi literatürde pek çok çalışmada önerilmektedir. Biz bu çalışmada mevcut literatüre ek olarak, SWI sekansının GRE T2* sekansında alınan görüntülere kıyasla lezyonları morfolojik olarak daha büyük gösterdiğini saptadık. Ayrıca SWI görüntüleme, SKM’ye eşlik eden okkült vasküler malformasyon saptanmasında ve fokal tip yüzeyel siderozis tanısında GRE T2* görüntülemeye kıyasla kesin bir tanısal üstünlüğe sahiptir.

Motor Band Sign in Motor Neuron Disease: A Marker for Upper Motor Neuron Involvement.

The prevalence and role of the motor band sign (MBS) remain unclear in motor neuron disease. We report the frequency of MBS in amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), its correlation with clinical upper motor neuron (UMN) signs, and prognostic value in ALS. We conducted a retrospective study of ALS, PLS, and controls with retrievable MRI between 2010 and 2018. We compared the frequencies of MBS across the three groups, and studied correlation between susceptibility-weighted MRI measurements in primary motor cortices and contralateral UMN features. Clinical outcomes were compared between ALS with and without MBS. Thirteen ALS, 5 PLS, and 10 controls were included (median age 60 years, IQR 54-66 years; 14/28 males). MBS was present in 9/13 (69.2%, 95% CI 38.9-89.6%) and 4/5 (80.0%, 95% CI 29.9-99.0%) of ALS and PLS, respectively, and none in controls. 2/13 (15.4%, 95% CI 2.7-46.3%) ALS and 3/5 (60.0%, 95% CI 17.0-92.7%) PLS had MBS in the absence of corticospinal T2/FLAIR hyperintensity sign. Susceptibility measurements in left motor cortices had a significantly positive correlation with contralateral UMN signs in ALS (τb = 0.628, p = 0.03). Similar but nonsignificant trends was observed for right motor cortices in ALS (τb = 0.516, p = 0.07). There were no significant differences in mRS at last follow-up, mortality, or time from symptom onset to last follow-up between ALS patients with and without MBS. We provide limited evidence that MBS and susceptibility quantification measurements in motor cortices may serve as surrogate markers of UMN involvement in motor neuron disease.

Modulation effect of substantia nigra iron deposition and functional connectivity on putamen glucose metabolism in Parkinson's disease.

Neurodegeneration of the substantia nigra affects putamen activity in Parkinson's disease (PD), yet in vivo evidence of how the substantia nigra modulates putamen glucose metabolism in humans is missing. We aimed to investigate how substantia nigra modulates the putamen glucose metabolism using a cross‐sectional design. Resting‐state fMRI, susceptibility‐weighted imaging, and [18F]‐fluorodeoxyglucose‐PET (FDG‐PET) data were acquired. Forty‐two PD patients and 25 healthy controls (HCs) were recruited for simultaneous PET/MRI scanning. The main measurements of the current study were R2* images representing iron deposition (28 PD and 25 HCs), standardized uptake value ratio (SUVr) images representing FDG‐uptake (33 PD and 25 HCs), and resting state functional connectivity maps from resting state fMRI (34 PD and 25 HCs). An interaction term based on the general linear model was used to investigate the joint modulation effect of nigral iron deposition and nigral‐putamen functional connectivity on putamen FDG‐uptake. Compared with HCs, we found increased iron deposition in the substantia nigra (p = .007), increased FDG‐uptake in the putamen (left: P FWE < 0.001; right: P FWE < 0.001), and decreased functional connectivity between the substantia nigra and the anterior putamen (left P FWE < 0.001, right: P FWE = 0.007). We then identified significant interaction effect of nigral iron deposition and nigral‐putamen connectivity on FDG‐uptake in the putamen (p = .004). The current study demonstrated joint modulation effect of the substantia nigra iron deposition and nigral‐putamen functional connectivity on putamen glucose metabolic distribution, thereby revealing in vivo pathological mechanism of nigrostriatal neurodegeneration of PD.

Role of intra-tumoral vasculature imaging features on susceptibility weighted imaging in differentiating primary central nervous system lymphoma from glioblastoma: a multiparametric comparison with pathological validation.

Primary objective of this study was to retrospectively evaluate the potential of a range of qualitative and quantitative multiparametric features assessed on T2, post-contrast T1, DWI, DCE-MRI, and susceptibility-weighted-imaging (SWI) in differentiating evenly sampled cohort of primary-central-nervous-system-lymphoma (PCNSL) vs glioblastoma (GB) with pathological validation. The study included MRI-data of histopathologically confirmed ninety-five GB and PCNSL patients scanned at 3.0T MRI. A total of six qualitative features (three from T2 and post-contrast T1, three from SWI: thin-linear-uninterrupted-intra-tumoral-vasculature, broken-intra-tumoral-microvasculature, hemorrhage) were analyzed by three independent radiologists. Ten quantitative features from DWI and DCE-MRI were computed using in-house-developed algorithms. For qualitative features, Cohen's Kappa-interrater-variability-analysis was performed. Z-test and independent t-tests were performed to find significant qualitative and quantitative features respectively. Logistic-regression (LR) classifiers were implemented for evaluating performance of individual and various combinations of features in differentiating PCNSL vs GB. Performance evaluation was done via ROC-analysis. Pathological validation was performed to verify disintegration of vessel walls in GB and rim of viable neoplastic lymphoid cells with angiocentric-pattern in PCNSL. Three qualitative SWI features and four quantitative DCE-MRI features (rCBVcorr, Kep, Ve, and necrosis-volume-percentage) were significantly different (p < 0.05) between PCNSL and GB. Best diagnostic performance was observed with LR classifier using SWI features (AUC-0.99). The inclusion of quantitative features with SWI feature did not improve the differentiation accuracy. The combination of three qualitative SWI features using LR provided the highest accuracy in differentiating PCNSL and GB. Thin-linear-uninterrupted-intra-tumoral-vasculature in PCNSL and broken-intra-tumoral-microvasculature with hemorrhage in GB are the major contributors to the differentiation.

Postoperative magnetic resonance imaging may predict poor outcome in children with severe traumatic brain injuries who undergo cranial surgery.

Multiple studies have evaluated the use of MRI for prognostication in pediatric patients with severe traumatic brain injury (TBI) and have found a correlation between diffuse axonal injury (DAI)-type lesions and outcome. However, there remains a limited understanding about the use of MRI for prognostication after severe TBI in children who have undergone cranial surgery. Children with severe TBI who underwent craniectomy or craniotomy at Primary Children's Hospital in Salt Lake City, Utah, between 2010 and 2019 were identified retrospectively. Of these 92 patients, 43 underwent postoperative brain MRI within 4 months of surgery. Susceptibility-weighted imaging (SWI) and FLAIR sequences were used to designate areas of hemorrhagic and nonhemorrhagic cerebral lesions related to DAI. Patients were then stratified based on the location of the DAI as read by a neuroradiologist as superficial, deep, or brainstem. The location of the DAI and other variables associated with poor outcome, including Glasgow Coma Scale (GCS) score, pediatric trauma score, mechanism of injury, and time to surgery, were analyzed for correlation with poor outcome. Outcomes were reported using the King's Outcome Scale for Childhood Head Injury (KOSCHI). In the 43 children with severe TBI who underwent postoperative brain MRI, the median GCS score on arrival was 4. The most common cause of injury was falls (14 patients, 33%). The most common primary intracranial pathology was subdural hematoma in 26 patients (60%), followed by epidural hematoma in 9 (21%). Fifteen patients (35%) had cerebral herniation and 31 (72%) had evidence of contusion. Variables associated with poor outcome included cerebral herniation (r = 0.338, p = 0.027) and location of DAI (r = 0.319, p = 0.037). In a separate analysis, brainstem DAI was shown to predict poor outcome, whereas location (no, superficial, or deep DAI) did not. Logistic regression showed that brainstem DAI (OR 22.3, p = 0.020) had a higher odds ratio than cerebral herniation (OR 10.5, p = 0.044) for poor outcome. Thirty-six children (84%) had a satisfactory outcome at last follow-up; 3 (7%) children died. The majority of children in this series who presented with a severe TBI and underwent craniectomy or craniotomy made a satisfactory recovery. In patients in whom there is a concern for poor outcome, the location of DAI-type lesions with SWI and FLAIR may assist in prognostication. The authors' results revealed that DAI-type lesions in the brainstem and evidence of cerebral herniation may indicate a poorer prognosis; however, more studies with larger cohorts are needed to make definitive conclusions.

Early imaging predictors of fetal cerebral ischemic injury in monochorionic twin pregnancy complicated by spontaneous single intrauterine death.

Monochorionic twin pregnancies are at increased risk of single intrauterine death (sIUD) and subsequent brain injury in the surviving twin owing to shared placentation. We assessed the association between middle cerebral artery peak systolic velocity (MCA-PSV) and cerebral injury on magnetic resonance imaging (MRI) and examined the association between cerebral findings on diffusion-weighted imaging (DWI) and those on T2-weighted imaging following spontaneous sIUD. This was a retrospective cohort study of monochorionic pregnancies complicated by spontaneous sIUD followed at a tertiary center between January 2008 and January 2020. Pregnancies with sIUD following laser treatment, those with selective feticide, double IUD occurring on the same day or sIUD before 14 weeks' gestation were excluded, as were cases in which MCA-PSV was not measured or DWI-MRI was not performed. The ability of MCA-PSV Doppler to predict subsequent cerebral injury on MRI was assessed, and DWI findings were analyzed and compared with those on susceptibility-weighted imaging (SWI) and T2-weighted MRI to determine its diagnostic accuracy. We assessed 64 monochorionic pregnancies complicated by spontaneous sIUD. Of these, 47 (73.4%) pregnancies underwent fetal brain MRI and met the inclusion criteria. Sixteen (34.0%) of these fetuses demonstrated cerebral injury on MRI. The median interval between the diagnosis of sIUD and MRI examination was 5 days. Fetuses with increased MCA-PSV > 1.5 multiples of the median (MoM) following sIUD were significantly more likely to demonstrate cerebral injury on MRI than were those with normal MCA-PSV (68.8% vs 38.7%; P = 0.05). The sensitivity and specificity of MCA-PSV > 1.5 MoM for predicting cerebral injury on MRI were 68.8% (95% CI, 41.3-88.9%) and 61.3% (95% CI, 42.2-78.2%), respectively. Patterns of early cerebral injury on T2-weighted and SWI-MRI included acute or subacute tissue swelling (n = 6), parenchymal atrophy (n = 7), loss of cortical ribbon (n = 1) and hemorrhage (n = 8). Early MRI within approximately 2 weeks after the diagnosis of sIUD demonstrated abnormal DWI along with coexisting SWI and T2-weighted sequelae in 56.3% (9/16) of cases. When DWI was normal and a second MRI examination was performed later (n = 7), there were no ischemic changes evident on T2-weighted imaging. Increased MCA-PSV is associated with, but predicts poorly, cerebral injury after sIUD. Early MRI with DWI within approximately 2 weeks after the diagnosis of sIUD is valuable in identifying any cerebral injury. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Resection of petroclival clear cell meningioma by the anterior transpetrosal approach: diagnosis of rare pathology and improvement of preoperative hearing disturbance.

Clear cell meningioma is a rare histological variant of meningioma, which often recurs aggressively. This video demonstrates a patient with a petroclival clear cell meningioma, which was resected completely through the anterior transpetrosal approach. The absence of intratumoral spotty signal voids on preoperative susceptibility-weighted imaging (SWI) suggested that the tumor was a meningioma rather than a schwannoma, although typical imaging features of meningioma were not observed. After surgery, the patient’s preoperative hearing disturbance improved from class D to class A, which the authors had sometimes experienced in cerebellopontine angle meningioma surgeries. Careful observation over a 2.5-year period revealed no tumor recurrence, without additional treatment.The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21219

MRI predictors for the conversion from contrast-enhancing to iron rim multiple sclerosis lesions

BackgroundIn multiple sclerosis (MS), iron rim lesions (IRLs) are characterized by progressive tissue matrix damage. Therefore, early identification could represent an interesting target for therapeutic intervention to minimize evolving tissue damage. The aim of this study was to identify magnetic resonance imaging (MRI) parameters predicting the conversion from contrast-enhancing to IRLs.MethodsWe retrospective identified MS patients scanned on the same 3 T MRI system presenting at least one supratentorial contrast-enhancing lesion (CEL) and a second MRI including susceptibility-weighted images after at least 3 months. On baseline MRI, pattern of contrast-enhancement was categorized as “nodular” or “ring-like”, apparent diffusion coefficient (ADC) maps were assessed for the presence of a peripheral hypointense rim. Lesion localization, quantitative volumes (ADC, lesion volume) and the presence of a central vein were assessed.ResultsEighty-nine acute contrast-enhancing lesions in 54 MS patients were included. On follow-up, 16/89 (18%) initially CELs converted into IRLs. CELs that converted into IRLs were larger and demonstrated significantly more often a ring-like contrast-enhancement pattern and a peripheral hypointense rim on ADC maps. Logistic regression model including the covariables pattern of contrast-enhancement and presence of a hypointense rim on ADC maps showed the best predictive performance (area under the curve = 0.932).DiscussionThe combination of a ring-like contrast-enhancement pattern and a peripheral hypointense rim on ADC maps has the ability to predict the evolution from acute to IRLs. This could be of prognostic value and become a target for early therapeutic intervention to minimize the associated tissue damage.

High-Resolution Vessel Wall MR Imaging in Diagnosis and Length Measurement of Cerebral Arterial Thrombosis: A Feasibility Study.

Detecting and measuring intraluminal thrombus has prognostic and therapeutic implications for stroke patients. To investigate the feasibility of 3D isotropic high-resolution T1w-CUBE imaging to detect and measure intraluminal thrombus in stroke patients. Retrospective. A total of 93 patients with acute (N=39) and subacute (N= 54) stroke. A 3.0 T/spin-echo echo-planar diffusion-weighted imaging (DWI), high-resolution T1w-CUBE imaging and 3D flow compensated gradient-echo susceptibility-weighted imaging (SWI). Data assessment was performed by three neuroradiologists with 11, 13, and 20 years of clinical experience. The accuracy of T1W-CUBE and SWI in diagnosing thrombosis was compared by using digital subtraction angiography (DSA) as the reference. For thrombus length measurement, the image quality of proximal and distal thrombus of T1w-CUBE images was first evaluated with a 4-point rating system. Then, the proximal and distal positions to lesions were determined on T1w-CUBE images and compared with those from DSA acquired during endovascular reperfusion therapy. If comparable both locations were found between CUBE and DSA, CUBE imaging can thus be considered for accurate measurement of thrombus length. Fleiss' Kappa; the area under the receiver operating characteristic (ROC) curve (AUC); Pearson's chi-squared test with Yates' continuity correction. Moderate-to-good interobserver agreements were validated with all Kappa coefficients higher than 0.40 in thrombus diagnosis and measurement. CUBE imaging showed higher clinical efficacy than SWI (AUC: 0.966 vs. 0.850) in thrombus diagnosis. Additionally, high quality of CUBE imaging was confirmed with 3 or 4 points rated by all three observers. Compared to intraoperative DSA, T1w CUBE showed consistent proximal and distal positions of thrombi in 16 of the 18 patients, validating the accuracy of T1w-CUBE in measuring thrombus length. T1w-CUBE imaging has potential to facilitate diagnosis and measurement of intraluminal thrombus. 4 TECHNICAL EFFICACY: Stage 2.

Rationale and design of the brain magnetic resonance imaging protocol for FutureMS: a longitudinal multi-centre study of newly diagnosed patients with relapsing-remitting multiple sclerosis in Scotland.

Introduction: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease. MS prevalence varies geographically and is notably high in Scotland. Disease trajectory varies significantly between individuals and the causes for this are largely unclear. Biomarkers predictive of disease course are urgently needed to allow improved stratification for current disease modifying therapies and future targeted treatments aimed at neuroprotection and remyelination. Magnetic resonance imaging (MRI) can detect disease activity and underlying damage non-invasively in vivo at the micro and macrostructural level. FutureMS is a prospective Scottish longitudinal multi-centre cohort study, which focuses on deeply phenotyping patients with recently diagnosed relapsing-remitting MS (RRMS). Neuroimaging is a central component of the study and provides two main primary endpoints for disease activity and neurodegeneration. This paper provides an overview of MRI data acquisition, management and processing in FutureMS. FutureMS is registered with the Integrated Research Application System (IRAS, UK) under reference number 169955. Methods and analysis: MRI is performed at baseline (N=431) and 1-year follow-up, in Dundee, Glasgow and Edinburgh (3T Siemens) and in Aberdeen (3T Philips), and managed and processed in Edinburgh. The core structural MRI protocol comprises T1-weighted, T2-weighted, FLAIR and proton density images. Primary imaging outcome measures are new/enlarging white matter lesions (WML) and reduction in brain volume over one year. Secondary imaging outcome measures comprise WML volume as an additional quantitative structural MRI measure, rim lesions on susceptibility-weighted imaging, and microstructural MRI measures, including diffusion tensor imaging and neurite orientation dispersion and density imaging metrics, relaxometry, magnetisation transfer (MT) ratio, MT saturation and derived g-ratio measures. Conclusions: FutureMS aims to reduce uncertainty around disease course and allow for targeted treatment in RRMS by exploring the role of conventional and advanced MRI measures as biomarkers of disease severity and progression in a large population of RRMS patients in Scotland.

Basal Ganglia Iron Content Increases with Glioma Severity Using Quantitative Susceptibility Mapping: A Potential Biomarker of Tumor Severity.

Background and Purpose: Gliomas have been found to alter iron metabolism and transport in ways that result in an expansion of their intracellular iron compartments to support aggressive tumor growth. This study used deep neural network trained quantitative susceptibility mapping to assess basal ganglia iron concentrations in glioma patients. Materials and Methods: Ninety-two patients with brain lesions were initially enrolled in this study and fifty-nine met the inclusion criteria. Susceptibility-weighted images were collected at 3.0 T and used to construct quantitative susceptibility maps via a deep neural network-based method. The regions of interest were manually drawn within basal ganglia structures and the mean voxel intensities were extracted and averaged across multiple slices. One-way ANCOVA tests were conducted to compare the susceptibility values of groups of patients based on tumor grade while controlling for age, sex, and tumor type. Results: The mean basal ganglia susceptibility for patients with grade IV tumors was higher than that for patients with grade II tumors (p = 0.00153) and was also higher for patients with grade III tumors compared to patients with grade II tumors (p = 0.020), after controlling for age, sex, and tumor type. Patient age influenced susceptibility values (p = 0.00356), while sex (p = 0.69) and tumor type (p = 0.11) did not. Conclusions: The basal ganglia iron content increased with glioma severity. Basal ganglia iron levels may thus be a useful biomarker in glioma prognosis and treatment, especially with regard to iron-based cancer therapies.

Low dihomo-γ-linolenic acid is associated with susceptibility vessel sign in cardioembolism

Background and aimsThe susceptibility vessel sign (SVS) on susceptibility-weighted image, a magnetic resonance imaging technique, reveals thrombi as hypointense signals. We aimed to examine the association between polyunsaturated fatty acid (PUFA) levels and the presence of the SVS and its length in cardioembolism due to atrial fibrillation (AF). MethodsConsecutive ischemic stroke patients who met the following inclusion criteria were screened: 1) patients with cardioembolism, defined by Trial of ORG 10172 in Acute Stroke Treatment, secondary to AF; 2) onset to door time within 24 h; 3) availability of magnetic resonance images, including susceptibility-weighted images, obtained at our hospital before performing recanalizing therapy; and 4) availability of PUFA measurements on the day of or the day after the hospital visit. We evaluated whether PUFA levels might be associated with the presence of the SVS and its length. ResultsWe retrospectively screened 1720 consecutive ischemic stroke patients, and included 137 patients (95 (69%) male, median age 73 years) who met the inclusion criteria in the analyses. In binomial logistic regression analysis, lower dihomo-γ-linolenic acid (DGLA) level was associated with the presence of SVS (odds ratio 0.545, 95% confidence interval 0.374 to 0.794, p = 0.002). Multiple linear regression analysis revealed a significant negative association between DGLA levels and SVS length (unstandardized coefficient −7.430, 95% confidence interval −13.256 to −1.603, p = 0.013). ConclusionLow DGLA level is associated with the presence of SVS and its length in patients with cardioembolism secondary to AF.

Multiparametric Framework Magnetic Resonance Imaging Assessment of Subtypes of Intracranial Germ Cell Tumors Using Susceptibility Weighted Imaging, Diffusion-Weighted Imaging, and Dynamic Susceptibility-Contrast Perfusion-Weighted Imaging Combined With Conventional Magnetic Resonance Imaging.

Intracranial germ cell tumors (iGCTs) are classified into two pathological subtypes (germinomas [GEs] and nongerminomatous germ cell tumors [NGGCTs]), with distinct treatment strategy and prognosis. Accurate preoperative determination of iGCT subtypes is essential to guide clinical decision-making and prognosis assessment. To investigate the diagnostic value of diffusion-weighted imaging (DWI), susceptibility weighted imaging (SWI), and dynamic susceptibility-contrast perfusion-weighted imaging (DSC-PWI) combined with conventional magnetic resonance imaging (cMRI) in finding subtypes of iGCTs. Retrospective. A total of 40 patients (45% male and 55% female) with iGCTs. A 3 T; &lt;T1WI, T2WI, T1WI + C, DWI, SWI, DSC-PWI&gt;. The parameters of DWI and DSC-PWI were calculated based on extracted parameters of multiparametric MRIs. The characteristics of SWI and cMRI were also compared in GEs and NGGCTs. The diagnostic efficacy of the minimum apparent diffusion coefficient (ADCmin), time-to-peak (TTP), relative mean transit time (rMTT), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) maps, and cMRI features in iGCT classification was evaluated by receiver operating characteristic curve (ROC) analyses. We calculated the sensitivity, specificity, AUC, and Youden index of the hybrid MR evaluation methods. A prospective cohort (five GEs and five NGGCTs) was designed as a simulation set to test the model. The significance threshold was set at P &lt; 0.01. The ADCmin (1039.100 ± 453.830 vs. 1400.050 ± 394.650), rCBF values (20.650 ± 6.260 vs. 51.170 ± 6.570), and TTP values (24.450 ± 3.160 vs. 28.950 ± 5.120) were significantly lower in GEs than in NGGCTs. The combination of ADCmin, DSC-PWI, and cMRI showed the heights AUC (AUC=0.962). The iGCT multiparametric framework showed the AUC was 0.958 in the simulation set. The iCGT multiparametric framework might be an effective diagnostic approach of iGCT subtype. The application of cMRI (T1WI, T2WI, and Gd-T1WI) with advanced imaging modalities (DWI, SWI, and PWI) had the best performance for classifying iGCT subtypes. 3 TECHNICAL EFFICACY: Stage 2.

Automated Differentiation of Atypical Parkinsonian Syndromes Using Brain Iron Patterns in Susceptibility Weighted Imaging.

In recent studies, iron overload has been reported in atypical parkinsonian syndromes. The topographic patterns of iron distribution in deep brain nuclei vary by each subtype of parkinsonian syndrome, which is affected by underlying disease pathologies. In this study, we developed a novel framework that automatically analyzes the disease-specific patterns of iron accumulation using susceptibility weighted imaging (SWI). We constructed various machine learning models that can classify diseases using radiomic features extracted from SWI, representing distinctive iron distribution patterns for each disorder. Since radiomic features are sensitive to the region of interest, we used a combination of T1-weighted MRI and SWI to improve the segmentation of deep brain nuclei. Radiomics was applied to SWI from 34 patients with a parkinsonian variant of multiple system atrophy, 21 patients with cerebellar variant multiple system atrophy, 17 patients with progressive supranuclear palsy, and 56 patients with Parkinson’s disease. The machine learning classifiers that learn the radiomic features extracted from iron-reflected segmentation results produced an average area under receiver operating characteristic curve (AUC) of 0.8607 on the training data and 0.8489 on the testing data, which is superior to the conventional classifier with segmentation using only T1-weighted images. Our radiomic model based on the hybrid images is a promising tool for automatically differentiating atypical parkinsonian syndromes.

Relationship between brain iron deposition and mitochondrial dysfunction in idiopathic Parkinson\u2019s disease

BackgroundThe underlying pathophysiology of Parkinson's disease is complex, involving different molecular pathways, including brain iron deposition and mitochondrial dysfunction. At a molecular level, these disease mechanisms are likely interconnected. Therefore, they offer potential strategies for disease-modifying treatments. We aimed to investigate subcortical brain iron deposition as a potential predictor of the bioenergetic status in patients with idiopathic Parkinson’s disease.MethodsThirty patients with idiopathic Parkinson's disease underwent multimodal MR imaging (T1, susceptibility-weighted imaging, SWI) and 31phosphorus magnetic resonance spectroscopy imaging. SWI contrast-to-noise ratios served as a measure for brain iron deposition in the putamen, caudate, globus pallidus, and thalamus and were used in a multiple linear regression model to predict in-vivo energy metabolite ratios.ResultsSubcortical brain iron deposition, particularly in the putamen and globus pallidus, was highly predictive of the region-specific amount of high-energy-containing phosphorus metabolites in our subjects.ConclusionsOur study suggests that brain iron deposition but not the variability of individual volumetric measurements are highly predictive of mitochondrial impairment in vivo. These findings offer the opportunity, e.g., by using chelating therapies, to improve mitochondrial bioenergetics in patients with idiopathic Parkinson's disease.

Synergistic Role of Quantitative Diffusion Magnetic Resonance Imaging and Structural Magnetic Resonance Imaging in Predicting Outcomes After Traumatic Brain Injury.

This study aimed to assess if quantitative diffusion magnetic resonance imaging analysis would improve prognostication of individual patients with severe traumatic brain injury. We analyzed images of 30 healthy controls to extract normal fractional anisotropy ranges along 18 white-matter tracts. Then, we analyzed images of 33 patients, compared their fractional anisotropy values with normal ranges extracted from controls, and computed severity of injury to white-matter tracts. We also asked 2 neuroradiologists to rate severity of injury to different brain regions on fluid-attenuated inversion recovery and susceptibility-weighted imaging. Finally, we built 3 models: (1) fed with neuroradiologists' ratings, (2) fed with white-matter injury measures, and (3) fed with both input types. The 3 models respectively predicted survival at 1 year with accuracies of 70%, 73%, and 88%. The accuracy with both input types was significantly better (P < 0.05). Quantifying severity of injury to white-matter tracts complements qualitative imaging findings and improves outcome prediction in severe traumatic brain injury.