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Background: Hemodynamic changes are seen in the feeding arteries of arteriovenous malformations (AVMs). Phase-contrast MRI (PC-MRI) enables the acquisition of hemodynamic information from blood vessels. There is insufficient knowledge on which flow or velocity parameter best discriminates AVMs from healthy subjects. Purpose: To evaluate PC-MRI-measured flow and velocity in feeding arteries of AVMs before and, when possible, also after treatment and to compare these measurements to corresponding measurements in healthy controls. Materials and Methods: Highest flow (HF), lowest flow (LF), mean flow (MF), peak systolic velocity (PSV), end-diastolic velocity (EDV), and mean velocity (MV) were measured in feeding arteries in patients with intracranial AVMs using 2D PC-MRI at 3 T. Measurements were compared to previously reported values in healthy individuals. Values in patients above the 95th percentile in the healthy cohort were categorized as pathological. Nidus volume was measured using 3D time-of-flight MR angiography. Results: Ten patients with diagnosed AVMs were examined with PC-MRI. Among these, three patients also underwent follow-up PC-MRI after treatment. Pathological velocities (PSV, EDV, and MV) were seen in all five subjects with a nidus larger or equal to 5.7 cm3, whereas pathological flow values were not seen in all, that is, pathologic HF in three, pathologic LF in two, and pathologic MF in two. After treatment, there was a decrease in flow and velocity (all measured parameters). After treatment, velocities (PSV, EDV, and MV) were no longer abnormal compared to healthy controls. Conclusion: Patients with a large AVM nidus show pathological velocities, but less consistent flow increases. Following treatment, velocities normalize.
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Sediments polluted with hydrophobic organic contaminants (HOCs) and metals can pose environmental risks, yet effective remediation remains a challenge. We investigated a new composite sorbent comprising granular activated carbon (GAC) and a calcium-silicate (Polonite®, PO) for thin-layer capping of polluted sediment, with the aim to sequester both HOCs and metals. Box cores were collected in polluted Oskarshamn harbor, Sweden, and the sediments were treated with GAC and/or Polonite in a 10-week mesocosm study to measure endpoints ranging from contaminant immobilization to ecological side effects on native fauna and biogeochemical processes. The GAC particle size was 300-500 µm to reduce negative effects on benthic fauna (by being non-ingestible) and of biogenic origin (coconut) to have a small carbon footprint compared with traditional fossil ACs. The calcium-silicate was a fine-grained industrial by-product used to target metals and as a carrier for GAC to improve the cap integrity. GAC decreased the uptake of dioxins (PCDD/Fs) in the bivalve Macoma balthica by 47 % and the in vitro bioavailability of PCB by 40 %. The composite cap of GAC + Polonite decreased sediment-to-water release of Pb < Cu < Ni < Zn < Cd by 42-98 % (lowest to highest decrease) and bioaccumulation of Cd < Zn < Cu in the worm Hediste diversicolor by 50-65 %. Additionally, in vitro bioavailability of Pb < Cu < Zn, measured using digestive fluid extraction, decreased by 43-83 %. GAC showed no adverse effects on benthic fauna while Polonite caused short-term adverse effects on fauna diversity and abundance, partly due to its cohesiveness, which, in turn, can improve the cap integrity in situ. Fauna later recovered and bioturbated the cap. Both sorbents influenced biogeochemical processes; GAC sorbed ammonium, Polonite decreased respiration, and both sorbents reduced denitrification. In conclusion, the side effects were relatively mild, and the cap decreased the release and bioavailability of both HOCs and metals effectively, thus offering a promising sustainable and cost-effective solution to remediating polluted sediments.
Subject(s)
Calcium Compounds , Charcoal , Environmental Restoration and Remediation , Geologic Sediments , Silicates , Water Pollutants, Chemical , Geologic Sediments/chemistry , Charcoal/chemistry , Environmental Restoration and Remediation/methods , Silicates/chemistry , Sweden , Calcium Compounds/chemistry , Animals , MetalsABSTRACT
Background: Fetal ultrasound has limitations, especially if the patient is obese or in cases with oligohydramnios. Magnetic resonance imaging (MRI) can then be used as a complement, but only few studies have focused on examinations in the second trimester. Purpose: To validate MRI as a complement to diagnose fetal anomalies in the second trimester. Material and Methods: This retrospective study retrieved data from January 2008 to July 2012 from the Fetal Medicine Unit and Department of Radiology at Uppsala University Hospital. Ultrasound and MRI findings were reviewed in 121 fetuses in relation to the final diagnosis, including postpartum follow-up and autopsy results. Results: Of the 121 fetuses, 51 (42%) had a CNS anomaly and 70 (58%) a non-CNS anomaly diagnosed or suspected. MRI provided additional information in 21% of all cases without changing the management and revealed information that changed the management of the pregnancy in 13%. When a CNS anomaly was detected or suspected, the MRI provided additional information in 22% and changed the management in 10%. The corresponding figures for non-CNS cases were 21% and 16%, respectively. The proportion of cases with additional information that changed the management was especially high in patients with a BMI >30 kg/m2 (25%) and in patients with oligohydramnios (38%). In five cases in category III, false-positive ultrasound findings were identified. Conclusions: MRI in the second trimester complements ultrasound and improves diagnosis of fetal CNS- and non-CNS anomalies especially when oligohydramnios or maternal obesity is present.
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Radiological imaging to examine intracranial blood vessels is critical for preoperative planning and postoperative follow-up. Automated segmentation of cerebrovascular anatomy from Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) can provide radiologists with a more detailed and precise view of these vessels. This paper introduces a domain generalized artificial intelligence (AI) solution for volumetric monitoring of cerebrovascular structures from multi-center MRAs. Our approach utilizes a multi-task deep convolutional neural network (CNN) with a topology-aware loss function to learn voxel-wise segmentation of the cerebrovascular tree. We use Decorrelation Loss to achieve domain regularization for the encoder network and auxiliary tasks to provide additional regularization and enable the encoder to learn higher-level intermediate representations for improved performance. We compare our method to six state-of-the-art 3D vessel segmentation methods using retrospective TOF-MRA datasets from multiple private and public data sources scanned at six hospitals, with and without vascular pathologies. The proposed model achieved the best scores in all the qualitative performance measures. Furthermore, we have developed an AI-assisted Graphical User Interface (GUI) based on our research to assist radiologists in their daily work and establish a more efficient work process that saves time.
Subject(s)
Magnetic Resonance Angiography , Neural Networks, Computer , Workflow , Humans , Magnetic Resonance Angiography/methods , Artificial Intelligence , Retrospective Studies , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methodsABSTRACT
Children born very preterm often exhibit atypical gaze behaviors, affect recognition difficulties and are at risk for cerebral white matter damage. This study explored links between these sequalae. In 24 12-year-old children born very preterm, ventricle size using Evans and posterior ventricle indices, and corpus callosum area were used to measure white matter thickness. The findings revealed a correlation between less attention towards the eyes and larger ventricle size. Ventricle and posterior corpus callosum sizes were correlated to affect-recognition proficiency. Findings suggest a link between white matter damage, gaze behavior, and affect recognition accuracy, emphasizing a relation with social perception.
Subject(s)
Magnetic Resonance Imaging , Humans , Pilot Projects , Female , Child , Male , Infant, Extremely Premature/physiology , White Matter/diagnostic imaging , Recognition, Psychology/physiology , Corpus Callosum/diagnostic imaging , Cerebral Ventricles/diagnostic imaging , Fixation, Ocular/physiologyABSTRACT
BACKGROUND: Paired cerebral blood flow (CBF) measurement is usually acquired before and after vasoactive stimulus to estimate cerebrovascular reserve (CVR). However, CVR may be confounded because of variations in time-to-maximum CBF response (tmax) following acetazolamide injection. With a mathematical model, CVR can be calculated insensitive to variations in tmax, and a model offers the possibility to calculate additional model-derived parameters. A model that describes the temporal CBF response following a vasodilating acetazolamide injection is proposed and evaluated. METHODS: A bi-exponential model was adopted and fitted to four CBF measurements acquired using arterial spin labelling before and initialised at 5, 15 and 25 min after acetazolamide injection in a total of fifteen patients with Moyamoya disease. Curve fitting was performed using a non-linear least squares method with a priori constraints based on simulations. RESULTS: Goodness of fit (mean absolute error) varied between 0.30 and 0.62 ml·100 g-1·min-1. Model-derived CVR was significantly higher compared to static CVR measures. Maximum CBF increase occurred earlier in healthy- compared to diseased vascular regions. CONCLUSIONS: The proposed mathematical model offers the possibility to calculate CVR insensitive to variations in time to maximum CBF response which gives a more detailed characterisation of CVR compared to static CVR measures. Although the mathematical model adapts generally well to this dataset of patients with MMD it should be considered as experimental; hence, further studies in healthy populations and other patient cohorts are warranted.
Subject(s)
Acetazolamide , Cerebrovascular Circulation , Moyamoya Disease , Humans , Moyamoya Disease/diagnostic imaging , Moyamoya Disease/physiopathology , Moyamoya Disease/drug therapy , Acetazolamide/pharmacology , Cerebrovascular Circulation/drug effects , Female , Male , Adult , Middle Aged , Models, Theoretical , Young Adult , Vasodilator Agents/pharmacology , Magnetic Resonance Imaging , Brain/diagnostic imaging , Brain/blood supplyABSTRACT
Although most pituitary neuroendocrine tumors (PitNETs)/pituitary adenomas remain intrasellar, a significant proportion of tumors show parasellar invasive growth and 6% to 8% infiltrate the bone structures, thus affecting the prognosis. There is an unmet need to identify novel markers that can predict the parasellar growth of PitNETs. Furthermore, mechanisms that regulate bone invasiveness of PitNETs and factors related to tumor vascularization are largely unknown. We used genome-wide mRNA analysis in a cohort of 77 patients with PitNETs of different types to explore the differences in gene expression patterns between invasive and noninvasive tumors with respect to the parasellar growth and regarding the rare phenomenon of bone invasiveness. Additionally, we studied the genes correlated to the contrast enhancement quotient, a novel radiological parameter of tumor vascularization. Most of the genes differentially expressed related to the parasellar growth were genes involved in tumor invasiveness. Differentially expressed genes associated with bone invasiveness are involved in NF-κB pathway and antitumoral immune response. Lack of clear clustering regarding the parasellar and bone invasiveness may be explained by the influence of the cell lineage-related genes in this heterogeneous cohort of PitNETs. Our transcriptomics analysis revealed differences in the molecular fingerprints between invasive, including bone invasive, and noninvasive PitNETs, although without clear clustering. The contrast enhancement quotient emerged as a radiological parameter of tumor vascularization, correlating with several angiogenesis-related genes. Several of the top genes related to the PitNET invasiveness and vascularization have potential prognostic and therapeutic application requiring further research.
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BACKGROUND: Phase-contrast magnetic resonance imaging (PC-MRI) quantifies blood flow and velocity noninvasively. Challenges arise in neurovascular disorders due to small vessels. We evaluated the impact of voxel size, number of signal averages (NSA), and velocity encoding (VENC) on PC-MRI measurement accuracy and precision in a small-lumen vessel phantom. METHODS: We constructed an in vitro model with a constant flow rate using a 2.2-mm inner diameter plastic tube. A reservoir with a weight scale and timer was used as standard reference. Gradient-echo T1 weighted PC-MRI sequence was performed on a 3-T scanner with varying voxel size (2.5, 5.0, 7.5 mm3), NSA (1, 2, 3), and VENC (200, 300, 400 cm/s). We repeated measurements nine times per setting, calculating mean flow rate, maximum velocity, and least detectable difference (LDD). RESULTS: PC-MRI flow measurements were higher than standard reference values (mean ranging from 7.3 to 9.5 mL/s compared with 6.6 mL/s). Decreased voxel size improved accuracy, reducing flow rate measurements from 9.5 to 7.3 mL/s. The LDD for flow rate and velocity varied between 1 and 5%. The LDD for flow rate decreased with increased voxel size and NSA (p = 0.033 and 0.042). The LDD for velocity decreased with increased voxel size (p < 10-16). No change was observed when VENC varied. CONCLUSIONS: PC-MRI overestimated flow. However, it has high precision in a small-vessel phantom with constant flow rate. Improved accuracy was obtained with increasing spatial resolution (smaller voxels). Improved precision was obtained with increasing signal-to-noise ratio (larger voxels and/or higher NSA). RELEVANCE STATEMENT: Phase-contrast MRI is clinically used in large vessels. To further investigate the possibility of using phase-contrast MRI for smaller intracranial vessels in neurovascular disorders, we need to understand how acquisition parameters affect phase-contrast MRI-measured flow rate and velocity in small vessels. KEY POINTS: ⢠PC-MRI measures flow and velocity in a small lumen phantom with high precision but overestimates flow rate. ⢠The precision of PC-MRI measurements matches the precision of standard reference for flow rate measurements. ⢠Optimizing PC-MRI settings can enhance accuracy and precision in flow rate and velocity measurements.
Subject(s)
Magnetic Resonance Imaging , Blood Flow Velocity/physiology , Magnetic Resonance Imaging/methods , Signal-To-Noise Ratio , Phantoms, Imaging , Reproducibility of ResultsABSTRACT
Premenstrual dysphoric disorder (PMDD) is a mood disorder for which selective progesterone receptor modulator (SPRM) treatment has been demonstrated to be beneficial. The neural signatures of this treatment have been so far identified as greater fronto-cingulate reactivity during aggressive response to provocation, but no changes in terms of gray matter structure. White matter has recently been found to differ between patients with PMDD and healthy controls. The present study thus sought to investigate the relationship between white matter volume and SPRM treatment in patients with PMDD. A pharmaco-neuroimaging study was conducted on patients with PMDD participating in a randomized controlled trial. Participants underwent magnetic resonance imaging before and after treatment randomization to ulipristal acetate (an SPRM), or placebo, for three months. The interaction effect of treatment by time on white matter volume (WMV) was assessed. Voxel based morphometry analyses were performed on both a whole brain exploratory level and on regions of interest. No treatment effect was observed on WMV in any region, including the anterior thalamic radiations, cingulum, forceps minor, fornix, inferior fronto-occipital fasciculus, superior cerebellar peduncle, superior longitudinal fasciculus, and uncinate fasciculus. This is the first finding to indicate that no white matter volume alterations follow three-month progesterone antagonism, suggesting that white matter volume does not participate in symptom relief upon SPRM treatment for PMDD.
Subject(s)
Premenstrual Dysphoric Disorder , White Matter , Female , Humans , Premenstrual Dysphoric Disorder/diagnostic imaging , Premenstrual Dysphoric Disorder/drug therapy , White Matter/diagnostic imaging , White Matter/pathology , Receptors, Progesterone , Brain/diagnostic imaging , Brain/pathology , Gray Matter/diagnostic imaging , Gray Matter/pathologyABSTRACT
A 30-year-old man presented with minute-long episodes of vertigo and severe autophony. CVEMP showed a decreased threshold when testing the left side, potentially indicating SSCD. A subsequent MRI demonstrated a multi-lobulated, cystic mass in the temporal bone and the radiological diagnosis at that time was ELST. Tumor excision was performed, and microscopic examination of the excised material revealed fibrovascular tissue without signs of papillary or cystic projections. The conclusion of the histological assessment rendered a diagnosis of angiofibroma. We were unable to find a previous report of ENA originating around the endolymphatic sac. Laryngoscope, 134:1897-1900, 2024.
Subject(s)
Angiofibroma , Bone Neoplasms , Ear Neoplasms , Endolymphatic Sac , Labyrinth Diseases , Male , Humans , Adult , Endolymphatic Sac/surgery , Endolymphatic Sac/pathology , Angiofibroma/diagnostic imaging , Angiofibroma/surgery , Labyrinth Diseases/pathology , Ear Neoplasms/diagnostic imaging , Ear Neoplasms/surgery , Vertigo , Bone Neoplasms/pathologyABSTRACT
PURPOSE: Very preterm birth increases risk for neonatal white matter injury, but there is limited data on to what extent this persists into adolescence and how this relates to ophthalmological outcomes. The aim of this study was to assess brain MRI findings in 12-year-old children born very preterm compared to controls and their association with concurrent ophthalmological outcomes. METHODS: We included 47 children born very preterm and 22 full-term controls (gestational age <32 and >37 weeks, respectively). Brain MRI findings were studied in association with concurrent ophthalmological outcomes at 12-year follow-up. RESULTS: Evans index (0.27 vs 0.25, p<0.001) and a proposed "posterior ventricle index" (0.47 vs 0.45, p=0.018) were increased in children born very preterm. Higher gestational age associated with larger corpus callosum area (ß=10.7, 95%CI 0.59-20.8). Focal white matter lesions were observed in 15 (32%) of very preterm children and in 1 (5%) of full-term controls. Increased posterior ventricle index increased risk for visual acuity ≤1.0 (OR=1.07×1011, 95%CI=7.78-1.48×1021) and contrast sensitivity <0.5 (OR=2.6×1027, 95%CI=1.9×108-3.5×1046). Decreased peritrigonal white matter thickness associated with impaired visual acuity (ß=0.04, 95%CI 0.002-0.07). CONCLUSION: More white matter lesions and evidence of lower white matter volume were found in children born very preterm compared with full-term controls at 12-year follow-up. The association between larger posterior ventricle index and reduced visual acuity and contrast sensitivity suggests disturbances of the posterior visual pathway due to diffuse white matter lesions.
Subject(s)
Premature Birth , White Matter , Child , Female , Infant, Newborn , Humans , Adolescent , Infant , Brain/diagnostic imaging , Brain/pathology , Infant, Extremely Premature , Premature Birth/pathology , Magnetic Resonance Imaging , White Matter/diagnostic imaging , White Matter/pathologyABSTRACT
Segmentation of major brain vessels is very important for the diagnosis of cerebrovascular disorders and subsequent surgical planning. Vessel segmentation is an important preprocessing step for a wide range of algorithms for the automatic diagnosis or treatment of several vascular pathologies and as such, it is valuable to have a well-performing vascular segmentation pipeline. In this article, we propose an end-to-end multiscale residual dual attention deep neural network for resilient major brain vessel segmentation. In the proposed network, the encoder and decoder blocks of the U-Net are replaced with the multi-level atrous residual blocks to enhance the learning capability by increasing the receptive field to extract the various semantic coarse- and fine-grained features. Dual attention block is incorporated in the bottleneck to perform effective multiscale information fusion to obtain detailed structure of blood vessels. The methods were evaluated on the publicly available TubeTK data set. The proposed method outperforms the state-of-the-art techniques with dice of 0.79 on the whole-brain prediction. The statistical and visual assessments indicate that proposed network is robust to outliers and maintains higher consistency in vessel continuity than the traditional U-Net and its variations.
Subject(s)
Cerebrovascular Disorders , Humans , Cerebrovascular Disorders/diagnostic imaging , Brain/diagnostic imaging , Algorithms , Cerebral Arteries , Neural Networks, Computer , Image Processing, Computer-AssistedSubject(s)
Trigeminal Neuralgia , Humans , Trigeminal Neuralgia/surgery , Trigeminal Nerve , Head , Treatment OutcomeABSTRACT
Many women are pregnant during several percent of their lives. Occasionally, there is a need for neuroradiological examinations during pregnancy or lactation. In our clinical work, we regularly see that female patients are being withheld relevant diagnostic scans during pregnancy, due to insufficient knowledge or an unbalanced comparison between benefits and risks. This article describes the current knowledge regarding conditions for performing CT and MRI scans in pregnant and lactating patients, including the use of contrast media. PET scans and reactions to contrast media are briefly mentioned, but interventional radiology is not discussed.
Subject(s)
Contrast Media , Lactation , Pregnancy , Humans , Female , Magnetic Resonance Imaging , Breast Feeding , Tomography, X-Ray ComputedABSTRACT
Background: Cerebral hemodynamics in moyamoya disease (MMD) is complex and needs further elucidation. The primary aim of the study was to determine the association of the cerebrovascular reserve (CVR) with cerebral blood flow (CBF) disturbances, oxygen extraction fraction (OEFmax), and energy metabolism (CMRO2max) in MMD, using arterial spin label magnetic resonance imaging (ASL-MRI) before and after acetazolamide administration. Methods: Thirty-nine ASL-MRI scans with a concurrent acetazolamide challenge from 16 MMD patients at the Uppsala University Hospital, Sweden, 2016-2021, were retrospectively analyzed. CBF was assessed before and 5, 15, and 25 min after acetazolamide administration, and the maximal response CVRmax was used for further analyses. Dynamic susceptibility contrast (DSC) MRI was performed 30 min after acetazolamide injection, and the data were analyzed using the Cercare Medical Neurosuite to assess capillary transit time heterogeneity (CTTH; indicating microvascular function), OEFmax, and CMRO2max. Results: In the ACA territory, a lower CVRmax was associated with lower baseline CBF, higher CTTH, and higher OEFmax but not with CMRO2max in generalized estimating equation models. In the MCA territory, lower CVRmax was associated with lower baseline CBF and higher CMRO2max but not with CTTH and OEFmax.. Conclusion: Altogether, a compromised CVR in MMD patients reflected disturbances in macro-/microvascular blood flow, oxygenation, and CMRO2. ASL-MRI with acetazolamide challenge is a feasible and radiation-free alternative to positron emission tomography (PET) imaging in MMD.
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OBJECTIVE: A small posterior fossa (PF) has been hypothesized to explain the increased incidence of trigeminal neuralgia (TN) in females and could make microvascular decompression (MVD) more challenging. The aim of this study was to investigate the association between the PF volume and dimensions in relation to biological sex, type of neurovascular conflict (NVC), and outcome after MVD in classic TN. METHODS: In this observational study, 84 patients with TN operated on with MVD with a preoperative head computed tomography(CT) scan were included. Eighty-two adults without TN who had undergone head CT for other reasons were included as controls. PF volume and dimensions (x-axis, y-axis, and z-axis) were evaluated on the CT scans. For the patients with TN, Barrow Neurological Institute (BNI) grade was evaluated 6 months after MVD. RESULTS: There was no difference in PF volume or dimensions between the patients with TN and controls. Women showed a smaller volume and narrower (x-axis) PF than men, but these differences did not manifest when comparing patients with TN and controls within each sex. Patients with an NVC involving the superior cerebellar artery had a narrower (x-axis) and shorter (y-axis) PF than did patients with an NVC resulting from other arteries. PF volume or dimensions were not associated with BNI grade after MVD. CONCLUSIONS: PF anatomy was related to the NVC type but did not differ between patients with TN and controls and was not related to the surgical outcome after MVD.
Subject(s)
Microvascular Decompression Surgery , Trigeminal Neuralgia , Adult , Male , Humans , Female , Trigeminal Neuralgia/diagnostic imaging , Trigeminal Neuralgia/surgery , Trigeminal Neuralgia/complications , Microvascular Decompression Surgery/adverse effects , Academies and Institutes , Arteries/surgery , Treatment Outcome , Retrospective StudiesABSTRACT
BACKGROUND: Immunoglobulin gamma (IgG) oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) are absent in a small group of multiple sclerosis (MS) patients. According to previous research, OCB-negative MS patients differ genetically but not clinically from OCB-positive MS patients. However, whether OCB-negative MS is a unique immunological and clinical entity remains unclear. The absence of OCB poses a significant challenge in diagnosing MS. (1) Objective: The objective of this study was twofold: (1) to determine the prevalence of OCB-negative MS patients in the Uppsala region, and (2) to assess the frequency of misdiagnosis in this patient group. (2) Methods: We conducted a retrospective study using data from the Swedish MS registry (SMSreg) covering 83% of prevalent MS cases up to 20 June 2020 to identify all MS patients in the Uppsala region. Subsequently, we collected relevant information from the medical records of all OCB-negative MS cases, including age of onset, gender, presenting symptoms, MRI features, phenotype, Expanded Disability Status Scale (EDSS) scores, and disease-modifying therapies (DMTs). (3) Results: Out of 759 MS patients identified, 69 had an OCB-negative MS diagnosis. Upon re-evaluation, 46 patients had a typical history and MRI findings of MS, while 23 had unusual clinical and/or radiologic features. An alternative diagnosis was established for the latter group, confirming the incorrectness of the initial MS diagnosis. The average EDSS score was 2.0 points higher in the MS group than in the non-MS group (p = 0.001). The overall misdiagnosis rate in the cohort was 33%, with 22% of misdiagnosed patients having received DMTs. (4) Conclusions: Our results confirm that the absence of OCB in the CSF should raise suspicion of possible misdiagnosis in MS patients and prompt a diagnostic reassessment.
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PURPOSE: Moyamoya (MM) disease is characterized by progressive intracranial arterial stenosis. Patients commonly need revascularization surgery to optimize cerebral blood flow (CBF). Estimation of CBF and cerebrovascular reserve (CVR) is therefore necessary before and after surgery. However, assessment of CBF before and after indirect revascularization surgery with the multiple burr hole (MBH) technique in MM has not been studied extensively. In this study, we describe our initial experience using arterial spin labeling magnetic resonance perfusion imaging (ASL-MRI) for CBF and CVR assessment before and after indirect MBH revascularization surgery in MM patients. METHODS: Eleven MM patients (initial age 6-50 years, 1 male/10 female) with 19 affected hemispheres were included. A total of 35 ASL-MRI examinations were performed using a 3D-pCASL acquisition before and after i.v. acetazolamide challenge (1000 mg in adults and 10 mg/kg in children). Twelve MBH procedures were performed in seven patients. The first follow-up ASL-MRI was performed 7-21 (mean 12) months after surgery. RESULTS: Before surgery, CBF was 46 ± 16 (mean ± SD) ml/100 g/min and CVR after acetazolamide challenge was 38.5 ± 9.9 (mean ± SD)% in the most affected territory (middle cerebral artery). In cases in which surgery was not performed, CVR was 56 ± 12 (mean ± SD)% in affected hemispheres. After MBH surgery, there was a relative change in CVR compared to baseline (preop) of + 23.5 ± 23.3% (mean ± SD). There were no new ischemic events. CONCLUSION: Using ASL-MRI we followed changes in CBF and CVR in patients with MM. The technique was encouraging for assessments before and after revascularization surgery.