Susceptibility-weighted Angiography Research Articles

Prominent cerebral veins on susceptibility-weighted angiography in acute meningoencephalitis.

We have commonly observed prominent cerebral veins on susceptibility-weighted angiography (SWAN) in acute meningoencephalitis. This study aimed to investigate the clinical significance of these findings. Cerebral veins on SWAN of 98 patients with acute meningoencephalitis diagnosed from February 2016 through October 2020 were classified into three groups according to the degree of venous prominence (mild, 23; moderate, 53; and prominent, 22). Clinical variables and laboratory findings were compared between these groups. The influence of variables on the prediction of prominent cerebral veins was measured by random forest (RF) and gradient boosting machine (GBM). As cerebral veins became more prominent, cerebrospinal fluid (CSF) glucose level decreased (69.61±29.05vs. 59.72±22.57vs. 48.36±20.29mg/dL, p=.01) and CSF protein level increased (100.73±82.98vs. 104.73±70.99vs. 159.12±118.15mg/dL, p=.03). The etiology of meningoencephalitis, neurological symptoms, and increased intracranial pressure (ICP) signs differed between groups (p<.05). RF and GBM demonstrated that CSF protein level was the variable with the highest power to predict the prominent cerebral vein (mean decrease in node impurity: 4.19, relative influence: 50.66). The presence of prominent cerebral veins on SWAN in acute meningoencephalitis was significantly associated with a low CSF glucose level and a high CSF protein level, as well as ICP. Thus, the visual grade of the cerebral veins on SWAN may be utilized for the management of patients with acute meningoencephalitis.

Quantification of Iron Deposition in the Brain of Hypertensive Patients Using 3D-enhanced Susceptibility-weighted Angiography (ESWAN).

Cerebral microbleeds (CMBs) are commonly present in patients with hypertension, producing iron-containing metabolites. A small amount of regional iron deposition is hardly discernible on conventional magnetic resonance imaging (MRI). Three-dimensional enhanced susceptibility-weighted angiography (ESWAN) provides tissue images with high spatial resolution and signal-noise ratio, and has been widely used to measure brain iron deposition in neurodegenerative diseases and intracranial hemorrhage. The study aimed to demonstrate iron deposition in the brain of hypertensive patients using ESWAN. Twenty-seven hypertension patients, with or without CMBs, and 16 matched healthy controls (HCs) were enrolled. From the post-processed ESWAN images, phase and magnitude values of the regions of interest (ROIs) were calculated. Two-sample t-test and one-way variance analysis were applied to compare groups. The relationship between ESWAN parameters and clinical variables was assessed using Pearson's correlation coefficient. Compared to HCs, the phase value of the hippocampus, head of caudate nucleus (HCN), and substantia nigra (SN) was decreased in hypertension with the CMBs subgroup, while that of HCN and SN was decreased in hypertension without CMBs subgroup. Similarly, the magnitude value of the hippocampus, HCN, thalamus red nucleus, and SN was significantly lower in the hypertension group than HCs. In addition, the phase and magnitude values showed a correlation with clinical variables, including disease duration and blood pressure. Deep grey matter nuclei displayed greater iron content in hypertension patients. Iron deposition may precede the appearance of CMBs on MRI, serving as a potential marker of microvascular damage.

Clinical characteristics of familial and sporadic pediatric cerebral cavernous malformations and outcomes.

Cerebral cavernous malformation (CCM) is a subtype of the vascular malformations found within the cerebral cortex. Although rare and usually discovered incidentally, these vascular abnormalities can predispose patients to spontaneous cerebral hemorrhage and subsequently lead to a myriad of neurological symptoms at presentation such as seizures and other focal neurological deficits. Although the symptoms and presentations of CCM have been adequately described in the adult population, disease characteristics and outcomes have not been extensively described in the pediatric population. Furthermore, the etiology of CCM-e.g., familial versus sporadic disease, as well as the risk factors for hemorrhage and neurological deficits and predictors of clinical and surgical outcomes-has not been adequately explored in the pediatric population. The current study attempts to classify and characterize differences in the clinical presentation, characteristics, and outcomes of CCMs between familial and sporadic cases within the pediatric population. A retrospective review identified 131 pediatric patients with radiographically confirmed diagnosis of CCM. All pertinent demographic and clinical variables were collected. CCM lesions were characterized using T2-weighted and susceptibility-weighted angiography (SWAN) MRI. Statistical analysis was conducted using the t-test for continuous variables, whereas categorical variables were analyzed with the Fisher exact test or chi-square test. Multivariate analysis was performed using a Cox proportional hazards model with R version 4.2.0. This retrospective study identified 131 pediatric CCM patients with a mean age of 8.4 years, and 54% (n = 71) were male. Twenty-seven percent (n = 35) were identified as cases with familial CCM, with the remainder classified as sporadic. The most common symptoms at presentation included generalized symptoms (headaches, nausea, and vomiting) or seizures, with a large proportion of patients also presenting as asymptomatic. No significant differences were observed in severity of symptoms between patients harboring different forms of the disease. Patients with familial CCM were noted to have a larger lesion size on average (5.26 cm3 vs 1.6 cm3, p = 0.047). These patients also had a shorter progression-free follow-up interval, with 50% of patients showing progression by 888 days, compared with only 15% of sporadic CCM patients during the same period (p = 0.0019). Familial etiology of the disease and larger average lesion volume were independent, significant predictors of disease progression (p = 0.001, HR 3.29, 95% CI 1.65-6.54) and future hemorrhage (p = 0.023, HR 1.1, 95% CI 1.01-1.10), respectively. Familial and sporadic CCMs tend to present with similar characteristics within the pediatric population. Patients with the familial form of the disease have an increased risk of progressive disease in terms of further hemorrhagic events.

Characteristics of Focused Ultrasound Mediated Blood-Brain Barrier Opening in Magnetic Resonance Images.

The blood-brain barrier (BBB) is an obstacle for molecules to pass through from blood to the brain. Focused ultrasound is a new method which temporarily opens the BBB, which makes pharmaceutical delivery or removal of neurodegenerative proteins possible. This study was demonstrated to review our BBB opening procedure with magnetic resonance guided images and find specific patterns in the BBB opening. In this study, we reviewed the procedures and results of two clinical studies on BBB opening using focused ultrasound regarding its safety and clinical efficacy. Magnetic resonance images were also reviewed to discover any specific findings. Two clinical trials showed clinical benefits. All clinical trials demonstrated safe BBB opening, with no specific side effects. Magnetic resonance imaging showed temporary T1 contrast enhancement in the sonication area, verifying the BBB opening. Several low-signal intensity spots were observed in the T2 susceptibility-weighted angiography images, which were also reversible and temporary. Although these spots can be considered as microbleeding, evidence suggests these are not ordinary microbleeding but an indicator for adequate BBB opening. Magnetic resonance images proved safe and efficient BBB opening in humans, using focused ultrasound.

The role of asymmetrical prominent veins sign in early neurological deterioration of acute ischemic stroke patients.

Background and purposeAsymmetrical prominent veins sign (APVS) often appears on susceptibility-weighted angiography (SWAN) images in patients with acute stroke. Early neurological deterioration (END) is highly correlated with survival prognosis in patients with ischemic stroke. This study sought to explore the relationship between APVS and END in patients with acute stroke.MethodsThe subjects retrospectively enrolled in this study were patients with acute ischemic stroke in the middle cerebral artery supply area. All patients underwent head MRI, including the SWAN sequence, within 7 days of stroke symptom onset. END was defined as clinical deterioration or recurrence within 72 h after ischemic stroke. The volume of infarction on diffusion-weighted imaging was measured. Univariate and multivariate analyses were used to analyze the relationship between APVS and END. Spearman correlation between APVS grades and infarct volume, white matter hyperintensity (WMH) volume, and offending vessel were also analyzed.ResultsA total of 157 patients with middle cerebral artery infarct between September 2018 and April 2020 were included in the study. APVS appeared on MRI in 84 of 157 patients, and 34 of 157 patients were diagnosed with END. In patients with END, the proportion of severe APVS was higher than in patients without END (P = 0.001, x2 = 14.659). Patients with END were older and had a larger volume of infarct and WMH than patients without END (all P < 0.05). After adjustments were made for related risk factors of END, the severity of APVS was still related to END (OR = 2.56, 95% CI, 1.38–4.75; P for trend = 0.003). Spearman correlation showed that APVS grades were positively related to infarct volume (r = 0.289, P < 0.001) and 3-month modified Rankin Scale score (r = 0.203, P = 0.011) and negatively related to offending vessels (r = −0.170, P = 0.034).ConclusionAPVS may be an important predictor of END in patients with acute ischemic stroke.

Significance of Low Signal in Intracranial Vertebral Artery Wall Observed on Susceptibility-Weighted Angiography

Purpose: We aimed to investigate the clinical significance of the low signal in the intracranial vertebral artery wall observed on susceptibility-weighted angiography. Materials and Methods: We retrospectively reviewed susceptibility-weighted angiographies from 200 consecutive patients with acute ischemic stroke in the posterior circulation territory. The presence of eccentric or concentric low signals in the vertebral artery wall was examined and evaluated. The etiology of the low signal was also investigated as much as possible by referring to computed tomography and T1-weighted imaging (T1WI). We also compared its frequency in each stroke subtype. Results: A low signal was observed in 128/200 patients (64%). The low signals (58%) corresponded to vessel wall calcification in 74 of 128 patients and to vessel wall thickening showing intermediate to low (n = 8) or high (n = 16) signals on T1WI in 24 (19%) patients. The low signal did not have vessel wall thickening or calcification in 1 patient, and the cause of the low signal could not be verified in 29 patients. According to stroke subtypes, a low signal was observed in 14/14 (100%) vertebral artery dissections, all of which corresponded to intramural hematoma. A low signal was observed in 51/65 (78%) atherothromboses, which were significantly more frequent than cardioembolism (34/66; 52%) and small-artery disease (18/39; 46%) (p < 0.01). In atherothrombosis, calcification was the most common cause of low signal (n = 32; 63%). Conclusion: Low signals on susceptibility-weighted angiography were frequently observed in vertebral artery dissection and atherothrombosis, reflecting intramural hematoma in all of the former and predominantly calcification in the latter.

Paramagnetic rim lesions are associated with pathogenic CSF profiles and worse clinical status in multiple sclerosis: A retrospective cross-sectional study

Background: Paramagnetic rims have been observed as a feature of some multiple sclerosis (MS) lesions on susceptibility-sensitive magnetic resonance imaging (MRI) and indicate compartmentalized inflammation. Objective: To investigate clinical, MRI, and intrathecal (cerebrospinal fluid, CSF) associations of paramagnetic rim lesions (PRLs) using 3T MRI in MS. Methods: This is a retrospective, cross-sectional analysis. All patients underwent 3T MRI using a T2*-weighted sequence with susceptibility postprocessing (susceptibility-weighted angiography (SWAN) protocol, GE). SWAN-derived filtered-phase maps and corresponding T2-FLAIR images were manually reviewed to determine PRL. Descriptive statistics, t-tests, and regression determined demographic, clinical, MRI, and CSF associations with PRL. Results: A total of 147 MS patients were included; 79 of whom had available CSF. Forty-three percent had at least one PRL. PRL status (presence/absence) did not vary by sex or Expanded Disability Status Scale (EDSS) but was associated with younger age, shorter disease duration, worse disease severity, high-efficacy therapy use, and poorer dexterity, as well as lower age-adjusted brain volumes and cognitive processing speeds. PRL status was moreover associated with blood–brain barrier disruption as determined by pathologically elevated albumin quotient. Sensitivity analyses remained supportive of these findings. Conclusion: PRLs, an emerging noninvasive biomarker of chronic neuroinflammation, are confirmed to be associated with greater disease severity and newly shown to be preliminarily associated with blood–brain barrier disruption.

White Matter Tract Injury by MRI in CADASIL Patients is Associated With Iron Accumulation.

Widespread white matter (WM) injury is a hallmark feature of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, controversies about the mechanism of WM tract injury exist persistently. Excessive iron accumulation, frequently reported in CADASIL patients, might cause WM tract injury. To test the association between iron accumulation and WM tract injury in CADASIL patients. Retrospective. A total of 35 CADASIL patients (age = 50.4 ± 6.4, 62.9% female) and 48 healthy controls (age = 55.7 ± 8.0, 68.8% female). Diffusion-weighted spin-echo echo-planar sequence; enhanced susceptibility-weighted angiography (ESWAN) gradient echo sequence on a 3T scanner. The phase images acquired by ESWAN were used to calculate quantitative susceptibility mapping (QSM). Iron accumulation was evaluated in deep gray matters using QSM. WM tract injury was quantified by diffusion metrics based on WM major tracts skeleton. We compared iron deposition between groups and analyzed the correlation between WM tract injury and iron deposition in regions showing significant differences from healthy controls. Exploratory analysis was carried out to investigate whether WM tract injury mediated the relationship between iron deposition and cognitive impairment evaluated by Mini-Mental State Examination (MMSE). General linear model (GLM), partial correlation, stepwise linear regression and mediation analysis were used. The threshold of statistical significance was set as p < 0.05. Compared with healthy controls, CADASIL patients had significantly increased iron deposition in the caudate and putamen. Aberrant iron deposition in these two regions was significantly associated with decreased WM fractional anisotropy (FA) (caudate, r = -0.373； putamen, r = - 0.421), and increased radial diffusivity (RD) (caudate, r = 0.372; putamen, r = 0.386). Furthermore, WM tract injury mediated the relationship between iron deposition and cognitive impairment. Patients with CADASIL show increased iron deposition in the caudate and putamen that is correlated to WM tract injury, which may in turn mediate the association with cognitive impairment. 2 TECHNICAL EFFICACY: Stage 2.

Comparison of susceptibility-weighted angiography (SWAN) and T2 gradient-echo sequences for the detection of acute cerebral venous thrombosis.

To assess the diagnostic accuracy and lesion conspicuity of susceptibility-weighted angiography (SWAN) and T2* for the clot detection in acute cerebral venous thrombosis (CVT) by comparison with contrast-enhanced MR venography. Venous thrombi detection and conspicuity were assessed by two readers for 18 venous segments on both T2*, SWAN source images, 2D SWAN reformats matching with T2*, and 3D SWAN images (SWAN-MinIP). Images obtained with the three reading techniques were systematically scored and compared to CE MRV findings, in a blinded fashion, per patient and per segment, and compared to each other. In 30 patients, 137 thrombosed venous segments were evaluated. The sensitivity of T2*, SWAN source images, 2D SWAN, and SWAN MinIP were, respectively, of 89.3%/82.1%, 82.1%, and 82.1% for dural sinus thrombosis and of 100%/100%/100%/96.6% for cortical venous thrombosis. There were significant differences in thrombus detection between T2* and SWAN: T2* versus SWAN source images and 2D SWAN (p = 0.04) and versus SWAN MinIP (p = 0.03). There were no significant differences between the three modalities of SWAN images. T2* was more sensitive than all SWAN images for both sigmoid sinus thrombosis and intracranial internal jugular vein thrombosis (p = 0.04). Inter-observer agreement was slightly superior with T2* (p < 0.05). In this small cohort, SWAN sequence at 3T did not yield additional value for thrombus detection in acute CVT compared to T2*. This study highlights SWAN's greatest weakness both for diagnostic accuracy and lesion conspicuity compared to T2* for acute venous clot detection near the skull base.

The central vein sign is present in most infratentorial multiple sclerosis plaques

Background and purposeThere is growing evidence supporting the presence of the central vein sign (CVS) in the supratentorial brain as an imaging biomarker for multiple sclerosis (MS) diagnosis. Recently, using optimized susceptibility-weighted angiography (SWAN-venule), we detected CVS in 86% of supratentorial white matter lesions (WMLs) in the clinical setting on images obtained in a 3T MRI scanner. Despite the relevance of the infratentorial compartment, CVS prevalence in infratentorial MS plaques has not been investigated in detail. Our objective was to determine the proportion of MS infratentorial lesions showing CVS positivity. Materials and methodsWe included subjects with MS and other brain diseases showing at least one infratentorial lesion larger than 3 mm on 3D-FLAIR. Patients were scanned in a 3T MRI scanner (GE Medical Systems, discovery-MR750), applying a comprehensive protocol including post-contrast 3D-FLAIR and SWAN-venule sequences. CVS presence was confirmed by two trained raters. ResultsThirty MRIs of subjects with MS were analyzed. One hundred and one infratentorial lesions were detected on FLAIR, and 86% were centered by a vein. Fifteen MRIs from the non-MS group were analyzed, 19 lesions were visible ion FLAIR and 16% were positive for the CVS. ConclusionsSWAN-venule detects infratentorial lesions and highlights the central vein in MS plaques at 3T MRI. As occurs in the supratentorial brain, most infratentorial lesions are perivenular.

Diagnostic Accuracy of SWAN in the Diagnosis of Low-Flow Brain Vascular Malformations in Childhood

Abstract Purpose The main objective of this study is to demonstrate the diagnostic accuracy of susceptibility-weighted angiography (SWAN) in the diagnosis of slow-flow cerebral vascular malformations, especially developmental venous anomaly (DVA). We also aimed to determine the prevalence of DVAs identified by SWAN at 1.5 T. Methods We retrospectively evaluated 1,760 axial SWAN images for the diagnosis of low-flow vascular anomaly. Among them were 305 patients who underwent contrast-enhanced examination due to different indications. Postcontrast images were analyzed by different radiologists who were blinded to patients. The presence of DVA and other features such as location, length, depth, and direction of drainage vein was evaluated. Results Twenty-six patients with DVA had both SWAN and postcontrast images. There were four false-negative patients with SWAN. The sensitivity of the SWAN sequence was 84.6%. In addition, totally 77 DVA (4.36%), 2 capillary telangiectasia (0.11%), and 2 cavernous malformations (0.11%) were detected in 1,760 patients. Conclusion SWAN is an effective method for the diagnosis of developmental venous anomalies and other low-flow cerebral vascular malformations. Especially in the pediatric age, susceptibility-weighted imaging sequences are useful to limit contrast use.

In Vitro Study of Blood Clot Identification and Composition Assessment by Different Magnetic Resonance Sequences.

BackgroundGrowing data suggest that clot composition can impact revascularization outcomes and can potentially guide treatment strategies for stroke patients with large vessel occlusion. We performed an in vitro study to determine which magnetic resonance (MR) signaling characteristics correlate with clot compositions.MethodologyA total of 25 clot analogs were prepared by mixing human plasma and red blood cells (RBCs) with five different combinations (five samples for each combination), namely, Group A, fibrin-rich (95% plasma:5% RBCs); Group B, fibrin-rich (75% plasma:25% RBCs); Group C, intermediate (50% plasma:50% RBCs); Group D, RBC-rich (25% plasma:75% RBCs), and Group E, RBC-rich (5% plasma:95% RBCs). The prepared samples were then scanned with quantitative T2* mapping, T2 fast spin-echo (FSE), T2 gradient-echo (GRE), fluid-attenuated inversion recovery (FLAIR), and susceptibility-weighted angiography (SWAN). Thrombus-T2* relaxation time (TT2*RT) and signal intensity (SI) from different scanning sequences were measured in all groups. SIs between different groups were compared using a one-way analysis of variance. Correlation between TT2*RT and SI was determined using the Pearson correlation test.ResultsThe average TT2*RT decreased from 126 ms to 37 ms from fibrin-rich to RBC-rich clots (Groups A to E). Mean SIs of Groups D and E were lower than Groups A, B, and C on T2 mapping, T2 FSE, T2 GRE, FLAIR, and SWAN images (p < 0.00001). TT2*RT and SI were positively correlated on T2 mapping (R = 0.9628, p = 0.009).ConclusionDifferent compositions of blood clots can show different TT2*RT and SI on MR imaging. Quantitative T2* mapping and multicontrast MR scanning can help in the characterization of clots causing large vessel occlusion, which is useful to establish treatment strategies for stroke patients.

Serum Ceruloplasmin Depletion is Associated With Magnetic Resonance Evidence of Widespread Accumulation of Brain Iron in Parkinson's Disease.

Excessive iron accumulation is one of the main pathogeneses of Parkinson's disease (PD). Ceruloplasmin plays an important role in keeping the iron homoeostasis. To explore the association between serum ceruloplasmin depletion and subcortical iron distribution in PD. Prospective. One hundred and twenty-one normal controls, 34 PD patients with low serum ceruloplasmin (PD-LC), and 28 patients with normal serum ceruloplasmin (PD-NC). Enhanced susceptibility-weighted angiography (ESWAN) on a 3 T scanner. Quantitative susceptibility mapping was employed to quantify the regional iron content by using a semi-automatic method. Serum ceruloplasmin concentration was measured from peripheral blood sample. Clinical assessments were conducted by a neurologist. General linear model was used to compare the intergroup difference of region iron distribution among groups, and the statistics was adjusted by Bonferroni method (P < 0.01). Partial correlation analysis was used to detect the association between regional iron distribution and serum ceruloplasmin concentration (P < 0.05). Compared with normal controls, significant iron accumulation in substantia nigra, putamen, and red nucleus was observed in PD-LC, while the only region showing significant iron accumulation was SN in PD-NC. Between PD-NC and PD-LC, the iron accumulation in putamen remained significantly different, which had a negative correlation with serum ceruloplasmin in whole PD patients (r=-0.338, P=0.008). Nigral iron accumulation characterizes PD patients without significant association with serum ceruloplasmin. Differentially, when PD patients appear with reduced serum ceruloplasmin, more widespread iron accumulation would be expected with additionally involving putamen and red nucleus. All these findings provide insightful evidence for the abnormal iron metabolism behind the ceruloplasmin depletion in PD. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: 2.

No evidence of iron deposition in essential tremor: a susceptibility-weighted imaging study

To evaluate the role of iron deposition in subcortical nuclei of patients with essential tremor (ET). Twenty-three patients with ET underwent a standardized 3T-MRI protocol. We specifically assessed iron deposition using susceptibility-weighted angiography (SWAN) images in seven specific regions of interest (ROIs): the thalamus, putamen, globus pallidus, caudate nucleus, substantia nigra, red nucleus, and dentate nucleus. Tremor in ET patients was clinically assessed using the Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS). ET patient data were compared with data obtained from 23 Parkinson's disease (PD) patients and 14 healthy subjects (HS). No differences in iron deposition in the seven ROIs were found between ET patients and HS. Conversely, PD patients showed increased iron deposition in the substantia nigra in comparison with both ET patients and HS. Our results indicate the absence of iron deposition in subcortical nuclei of ET patients, which is generally considered a marker of neurodegeneration.

Utility of Susceptibility-Weighted Angiography Sequence in the Diagnosis of Ruptured Infectious Aneurysms

In a patient with infective endocarditis (IE), susceptibility-weighted angiography (SWAN) sequence revealed 2 intracranial infectious aneurysms (IIAs) as bright signal lesion, related to the high-velocity arterial flow within the IIAs. In addition, SWAN revealed a convexal subarachnoid hemorrhage-related to distal IIA rupture-as a dark signal. The risk of IIA rupture emphasizes the need for serial imaging follow-up in patients with IE receiving antibiotic therapy after endovascular treatment and after valve surgery. Considering its specific risks, particularly in patients with IE who may be on anticoagulation, digital subtraction angiography is not used routinely in this context. Therefore, SWAN might be an alternative method for selecting patients with IE who need conventional angiography and might be useful for serial follow-up and monitoring after treatment. Future studies should investigate the role of SWAN for the detection of IIAs.

Newer magnetic resonance imaging techniques in neurocysticercosis.

The definitive diagnosis of neurocysticercosis continues to be challenging. We evaluate the role of newer magnetic resonance imaging techniques including constructive interference in steady state, susceptibility-weighted imaging, arterial spin labelling and magnetic resonance spectroscopy in the diagnosis of neurocysticercosis. To study the utility of newer magnetic resonance imaging sequences in the diagnosis of neurocysticercosis. Eighty-five consecutive patients with neurocysticercosis attending a tertiary care hospital and teaching centre in northern India were included in the study. The diagnosis of neurocysticercosis was made by the Del Brutto criteria. All patients received treatment according to standard guidelines and were followed at 3-month intervals. The following magnetic resonance sequences were performed at baseline: T1 and T2-weighted axial sequences; T2 fluid-attenuated inversion recovery axial sequences; diffusion-weighted imaging; susceptibility-weighted imaging; pre and post-contrast T1-weighted imaging; heavily T2-weighted thin sections (constructive interference in steady state); arterial spin labelling (n = 19); and magnetic resonance spectroscopy (n = 24). The mean (±SD) age was 29.4 ± 12.9 years and 76.5% were men. Seizures were the commonest symptom (89.4%) followed by headache (24.3%), encephalitis (9.4%) and raised intracranial pressure (9.4%). Scolex could be visualised in 43.7%, 55.5% and 61.2% of neurocysticercosis patients using conventional, susceptibility-weighted angiography and constructive interference in steady state imaging sequences, respectively. Susceptibility-weighted angiography and constructive interference in steady state images resulted in significantly higher (P < 0.01) visualisation of scolex compared to conventional sequences. Newer magnetic resonance imaging modalities have a lot of promise for improving the radiological diagnosis of neurocysticercosis.

Susceptibility-weighted MR sequence for the evaluation of ovarian masses with torsion.

Adnexal torsion is a rare gynecologic emergency caused by twisting of an adnexal mass. Twisted vascular pedicle is the most specific imaging finding for adnexal torsion, however, identification of twisted vascular pedicle can be challenging. The purpose of this study is to evaluate the feasibility of susceptibility-weighted MR sequence (SWS) for the diagnosis of adnexal torsion. MR imaging including SWS (SWAN: susceptibility-weighted angiography) of surgically proven four benign ovarian masses with torsion (one acute and three subacute to chronic torsions) were retrospectively evaluated. Three cystic masses and one solid mass were included in this study. High signal intensity venous thrombus within the twisted vascular pedicle on T1-weighted imaging (T1WI) was detected in three lesions with subacute to chronic torsion (75%) but not in one lesion with acute torsion, whereas susceptibility-induced signal voids within the twisted vascular pedicle on SWAN were detected in all four lesions (100%). The demonstration of venous thrombus in the twisted vascular pedicle by SWS may be diagnostic for adnexal torsion. SWS can detect blood products sensitively and can reveal venous thrombus in the twisted vascular pedicle, which may be helpful for the diagnosis of adnexal torsion.

SWAN-Venule: An Optimized MRI Technique to Detect the Central Vein Sign in MS Plaques

Multiple sclerosis lesions develop around small veins that are radiologically described as the so-called central vein sign. With 7T MR imaging and magnetic susceptibility-based sequences, the central vein sign has been observed in 80%-100% of MS lesions in patients' brains. However, a lower proportion ∼50% has been reported at 3T using susceptibility-weighted angiography (SWAN). Our aim was to assess a modified version of SWAN optimized at 3T for sensitive detection of the central vein sign. Thirty subjects with MS were scanned on a 3T clinical MR imaging system. 3D T2-weighted FLAIR and optimized 3D SWAN called SWAN-venule, were acquired after injection of a gadolinium-based contrast agent. Patients showing >3 focal white matter lesions were included. The central vein sign was recorded by 2 trained raters on SWAN-venule images in the supratentorial brain. Twenty patients showing >3 white matter lesions were included. A total of 380 white matter lesions (135 periventricular, 144 deep white matter, and 101 juxtacortical) seen on both FLAIR and SWAN-venule images were analyzed. Overall, the central vein sign was detected in 86% of the white matter lesions (periventricular, 89%; deep white matter, 95%; and juxtacortical, 78%). The SWAN-venule technique is an optimized MR imaging sequence for highly sensitive detection of the central vein sign in MS brain lesions. This work will facilitate the validation and integration of the central vein sign to increase the diagnostic certainty of MS and further prevent misdiagnosis in clinical practice.

Silent susceptibility-weighted angiography to detect hemorrhagic lesions in the brain: a clinical and phantom study

To compare the effectiveness of silent susceptibility-weighted angiography (sSWAN), a new imaging technique with lower acoustic noise, with conventional susceptibility-weighted angiography (cSWAN) in the detection of intracranial hemorrhagic lesions. We measured the acoustic and background noise during sSWAN and cSWAN imaging and calculated the contrast-to-noise ratio (CNR) of the phantom consisting of eight chambers with different concentrations of superparamagnetic iron oxide. In the clinical study, we calculated the CNRs of hemorrhagic lesions in 15 patients and evaluated the images for conspicuity and artifact on each sequence and scored them on a 4-point scale. We also evaluated whether hypointense areas observed on sSWAN or cSWAN increased in size from those on T2*-weighted imaging (T2*-WI). Acoustic noise for sSWAN (57.9 ± 0.32 dB [background noise 51.3 dB]) was significantly less than that for cSWAN (89.0 ± 0.22 dB [background noise 50.9 dB]). The CNRs of phantoms for sSWAN were slightly but not significantly lower than those for cSWAN (P = 0.18). The CNRs of hemorrhagic lesions did not show significant differences between sSWAN and cSWAN (P = 0.17). There were no significant differences between sSWAN and cSWAN with respect to the scores for conspicuity, artifact, and change in size of hypointense areas from T2*-WI. sSWAN is equivalent to cSWAN with respect to the image quality for the detection of hemorrhagic lesions but has lower acoustic noise.

Hyperglycemia-induced seizures - Understanding the clinico- radiological association.

Objectives:To highlight the typical magnetic resonance imaging (MRI) findings in hyperglycemia-induced seizures and compare the results with similar previous studies with a brief mention of pathophysiological mechanisms.Materials and Methods:This retrospective study included medical and imaging records of six consecutive patients with hyperglycemia-induced seizures. The data analysis included a clinical presentation and biochemical parameters at admission. The MRI sequences were evaluated for region involved, presence of subcortical T2 hypo-intensity, cortical hyper-intensity, and restricted diffusion. Similar previous studies from the National Library of Medicine (NLM) were analyzed and compared with our study.Results:Twenty-four patients were included from four studies in previous literature for comparison. In our study, on imaging, posterior cerebral region was predominantly involved, with parietal involvement in 83.3%, followed by occipital, frontal, and temporal involvement in 33.3% patients compared with occipital in 58.3%, parietal in 45.8%, and frontal and temporal in 16.6% of patients in previous literature. The subcortical T2 hypo-intensity was present in 83.3% of the patients, cortical hyper-intensity in all patients, and restricted diffusion in 66.6% of the patients in our study compared with subcortical T2 hypo-intensity in 95.8% of the patients, cortical hyper-intensity in 62.5%, and restricted diffusion in 58.3% of the patients in previous literature.Conclusion:Although many etiologies present with subcortical T2 hypointensity, cortical hyperintensity, restricted diffusion, and postcontrast enhancement on MRI, the clinical setting of seizures in a patient with uncontrolled hyperglycemia, hyperosmolar state, and absence of ketones should suggest hyperglycemia-induced seizures to avoid misdiagnosis, unnecessary invasive investigations, and initiate timely management.Advances in Knowledge:Our study highlights the presence of posterior predominant subcortical T2, fluid-attenuated inversion recovery (FLAIR), and susceptibility-weighted angiography (SWAN) hypointensity; cortical hyperintensity; and restricted diffusion in hyperglycemia-induced seizures. The presence of T2 and SWAN hypointensity could support the hypothesis of possible deposition of free radicals and iron in the subcortical white matter.