Diffusion-weighted Imaging Abnormalities Research Articles

Unveiling Opportunities for Intervention: A Prospective Cohort Study Investigating the Clinical Significance of Diffusion-Weighted Imaging (DWI)-Fluid-Attenuated Inversion Recovery (FLAIR) Mismatch Beyond the Window Period in Acute Ischemic Stroke.

Acute ischemic stroke causes irreversible damage to the brain parenchymasurrounded by salvageable tissue known as the ischemic penumbra.Magnetic resonance imaging (MRI), particularly the mismatch between abnormal diffusion-weighted imaging (DWI) signals and normal fluid-attenuated inversion recovery (FLAIR) signals, plays a critical role in detecting ischemic penumbra. It also allows for the identification of patients who may benefit from reperfusion therapy. Hence, this prospective cohort study aimed to explore the correlation between DWI-FLAIR mismatch and clinical outcomes in acute ischemic stroke patients, specifically those with delayed or uncertain symptom onset, offering potential insights into reperfusion therapy. A total of 38 thrombotic stroke patients aged above 18 were included in this prospective cohort study. Baseline data, including demographics, lifestyle factors, and medical history, were recorded. DWI-FLAIR mismatch was evaluated through brain MRI within 4.5 hours to 12 hours of symptom onset. Of the cohort, 63.2% were males, predominantly in the 61-70 age group. Smoking and alcohol consumption were reported by 15.79% each. DWI-FLAIR mismatch was present in 20 out of 38 subjects. No statistically significant differences were noted in the mean National Institutes of Health Stroke Scale (NIHSS) and Modified Rankin Scale (MRS) scores between subjects with and without DWI-FLAIR mismatch. Thrombolysis in wake-up stroke subjects demonstrated a substantial reduction in mean MRS at discharge (1.29±0.95) and at six to eight weeks (1.71±1.11), suggesting potential benefits on functional outcomes. The prevalence of DWI-FLAIR mismatch was seen in the majority of patients beyond their window period and also showed beneficiary outcomes with a mean reduction in NHISS and MRS scores following thrombolysis.

Acute Magnetic Resonance Imaging Findings in Young Children With Moyamoya Disease

BackgroundTo describe the diffusion-weighted imaging (DWI) findings in young children with moyamoya disease (MMD) during the acute period of the condition. MethodsClinical data were collected from 12 children with MMD aged less than six years, in whom abnormalities were observed on DWI scans obtained within one week after the appearance of symptoms related to MMD. The DWI abnormalities were classified into gyral, atypical territorial, honeycomb, classical territorial, multiple-dot, border zone, and deep lacunar patterns. The severity of arterial stenosis was graded by angiographic stages that have been previously described. ResultsIn all but one child, the DWI abnormalities were restricted to the cerebral cortex. The lesions were gyral in nature in seven children and atypical territorial in five; all differed from those of typical arterial strokes. Internal carotid artery stenosis was observed in all 12 children, although the stenosis was mild in 11. The severity of arterial stenosis did not match the regions of ischemic lesions in some children. There was no statistically significant difference in the severity of arterial stenosis according to the presence or absence of ischemic lesions or the pattern of the lesions. ConclusionsLesions located mainly in the cerebral cortex, i.e., not in arterial territories, are characteristic of young children with MMD.

Prediction of underweight, short stature, and microcephaly based on brain diffusion-weighted imaging sequence in neonates with stage.2 of hypoxic-ischemic encephalopathy: A follow-up study.

Hypoxic-ischemic encephalopathy (HIE), caused due to reduced oxygenation and brain blood flow, occurs in 1-8 per 1000 live full-term births in developed countries and up to 26 per 1000 live in the developing world. The growth status of survivors of birth HIE has not been evaluated sufficiently. This study evaluated, the growth parameters (weight, height, and head circumference) of neonates with Sarnat stage.2 of HIE at 6, 10, and 12 months and its relationship with findings of neonatal brain diffusion-weighted imaging (DWI) sequence. Medical records and growth parameters of 35 neonates with gestational age 34 wk who were admitted with stage.2 of HIE in Neonatal Intensive Care Unit of Shahid Sadoughi hospital, Yazd, Iran from March 2021-March 2022, and its relationship with neonatal brain DWI sequence finding was evaluated. 15 girls and 20 boys with a mean birth weight of 2880.3 221.8 gr were evaluated. Conventional magnetic resonance imaging and DWI were found to be abnormal in 6 (17.1%) and 18 neonates (51.4%). The most abnormal finding of DWI was high signal in basal ganglia/thalamus in 9 neonates (25.7%). Abnormal DWI is more frequent in neonates with seizures and low birth weight. Hospital stay days were more prolonged in neonates with abnormal DWI. Microcephaly at 12 months was more frequent in children with abnormal DWI. In survivors of moderate neonatal HIE, abnormal brain DWI sequence might predict inappropriate head growth, and need close medical and nutritional interventions for growth improvement.

CGG Repeat Expansion in NOTCH2NLC Causing Overlapping Oculopharyngodistal Myopathy and Neuronal Intranuclear Inclusion Disease With Diffusion Weighted Imaging Abnormality in the Cerebellum

CGG Repeat Expansion in <i>NOTCH2NLC</i> Causing Overlapping Oculopharyngodistal Myopathy and Neuronal Intranuclear Inclusion Disease With Diffusion Weighted Imaging Abnormality in the Cerebellum

Accumulation Area of a Japanese PRNP P102L Variant Associated With Gerstmann-Sträussler-Scheinker Disease: The Ariake PRNP P102L Variant.

The coast of Kyushu Island on Ariake Sea in Japan is known to be an accumulation area for patients with a proline-to-leucine substitution mutation at residue 102 (P102L) of the human prion protein gene (PRNP), which is associated with Gerstmann-Sträussler-Scheinker disease. We designated this geographical distribution as the "Ariake PRNP P102L variant." The purpose of this study was to characterize the clinical features of this variant. We enrolled patients with the PRNP P102L variant who were followed up at the Saga University Hospital from April 2002 to November 2019. The clinical information of patients were obtained from medical records, including clinical histories, brain magnetic resonance imaging (MRI), and electroencephalography (EEG). A brain autopsy was performed on one of the participants. We enrolled 24 patients from 19 family lines, including 12 males. The mean age at symptom onset was 60.6 years (range, 41-77 years). The incidence rate of the Ariake PRNP P102L variant was 3.32/1,000,000 people per year in Saga city. The initial symptoms were ataxia (ataxic gait or dysarthria) in 19 patients (79.2%), cognitive impairment in 3 (12.5%), and leg paresthesia in 2 (8.3%). The median survival time from symptom onset among the 18 fatal cases was 63 months (range, 23-105 months). Brain MRI revealed no localized cerebellar atrophy, but sparse diffusion-weighted imaging abnormalities were detected in 16.7% of the patients. No periodic sharp-wave complexes were identified in EEG. Neuropathological investigations revealed uni- and multicentric prion protein (PrP) plaques in the cerebral cortex, putamen, thalamus, and cerebellum of one patient. Western blot analysis revealed 8-kDa proteinase-K-resistant PrP. This is the first report of the accumulation area of a PRNP P102L variant on the coast of Ariake Sea. The Ariake PRNP P102L variant can be characterized by a relatively long disease duration with sparse abnormalities in brain MRI and EEG relative to previous reports. Detailed interviews to obtain information on the birthplace and the family history of related symptoms are important to diagnosing a PRNP P102L variant.

Hyperintensity on Diffusion‐Weighted MRI and Clinical Correlations in Probable Creutzfeldt‐Jakob Disease

AbstractBackgroundAlthough definite diagnosis for Creutzfeldt‐Jakob disease(CJD) requires tissue confirmation, diffusion‐weighted imaging (DWI) of the brain has an important role in the diagnosis of CJD. Also elevated CSF total tau (t‐tau) is considered as an useful CJD biomarker revealing neuro‐axonal damage although it is not specific for CJD. In this study, we attempted to find out the association between DWI abnormality and CSF t‐tau in CJD patients.MethodWe retrospectively analyzed the medical records reported as human prion disease.The patients who had been diagnosed and reported as human prion disease to Korea Disease Control and Prevention Agency (KDCA) by medical institutions in South Korea during the period of January 1, 2019 to December 31, 2019 were included in this study. The clinical information of the reported patients had been reviewed by a clinical review committee of KDCA for CJD and the patients who had fulfilled the criteria for probable CJD were evaluated for clinical, radiological, and laboratory findings.ResultA total of 186 patients had been reported as suspected human prion disease during the one‐year period and 53 patients who satisfied the criteria for human prion disease were included in the analysis. The most common clinical presentation was cognitive change, followed by cerebellar dysfunction and extrapyramidal symptoms. Hyperintense lesions on DWI were observed in 52 patients (98%). The involvement of neocortex was observed in almost all patients (98%) and asymmetrical and bilateral hyperintensities on DWI were common. Among neocortex, the most commonly involved region was parietal lobe, followed by frontal lobe, temporal lobe, and occipital lobe. DWI abnormality in striatum and/or thalamus was observed in 65.3% of patients. CSF t‐tau was elevated in sporadic CJD patients (8998.3±11903.7 pg/ml) There was no significant association between the extent of the lesions on DWI and CSF t‐tau.ConclusionIn this study,most of the patients with probable CJD showed DWI abnormality mainly on neocortex (parietal &gt; frontal &gt; temporal &gt; occipital) but the association between the pattern of DWI abnormality and the level of CSF t‐tau was not observed.

Deep Learning-Driven Transformation: A Novel Approach for Mitigating Batch Effects in Diffusion MRI Beyond Traditional Harmonization.

"Batch effect" in MR images, due to vendor-specific features, MR machine generations, and imaging parameters, challenges image quality and hinders deep learning (DL) model generalizability. We aim to develop a DL model using contrast adjustment and super-resolution to reduce diffusion-weighted images (DWIs) diversity across magnetic field strengths and imaging parameters. Retrospective. The DL model was built using an open dataset from one individual. The MR machine identification model was trained and validated on a dataset of 1134 adults (54% females, 46% males), with 1050 subjects showing no DWI abnormalities and 84 with conditions like stroke and tumors. The 21,000 images were divided into 80% for training, 20% for validation, and 3500 for testing. Seven MR scanners from four manufacturers with 1.5 T and 3 T magnetic field strengths. DWIs were acquired using spin-echo sequences and high-resolution T2WIs using the T2-SPACE sequence. An experienced, board-certified radiologist evaluated the effectiveness of restoring high-resolution T2WI and harmonizing diverse DWI with metrics such as PSNR and SSIM, and the texture and frequency attributes were further analyzed using gray-level co-occurrence matrix and 1-dimensional power spectral density. The model's impact on machine-specific characteristics was gauged through the performance metrics of a ResNet-50 model. Comprehensive statistical tests were employed for statistical robustness, including McNemar's test and the Dice index. Our DL protocol reduced DWI contrast and resolution variation. ResNet-50 model's accuracy decreased from 0.9443 to 0.5786, precision from 0.9442 to 0.6494, recall from 0.9443 to 0.5786, and F1 score from 0.9438 to 0.5587. The t-SNE visualization indicated more consistent image features across multiple MR devices. Autoencoder halved learning iterations; Dice coefficient >0.74 confirmed signal reproducibility in 84 lesions. This study presents a DL strategy to mitigate batch effects in diffusion MR images, improving their quality and generalizability. 3 TECHNICAL EFFICACY: Stage 1.

Cerebral Malaria and Cytotoxic Lesions of the Corpus Callosum.

To the Editors: Malaria is a common cause of morbidity and mortality worldwide. According to the WHO, 229 million cases and 409,000 deaths were reported worldwide in 2020.1 Children account for a high burden of malaria-related mortality and are at a higher risk of developing cerebral malaria (CM).1 A 12-year-old, previously healthy female from Guinea-Bissau was admitted 1 day after arriving in Portugal with a 2-day history of headache, generalized myalgia, and high-grade fever. Physical examination was unremarkable, except for pallor, icteric sclerae, and nontender hepatomegaly (4 cm). The patient was hemodynamically stable (BP, 101/52 mmHg; HR, 111 bpm), but shortly after admission, vomiting, lethargy, and impaired consciousness were observed (Glasgow coma score 11). She presented with anemia (hemoglobin, 10.0 g/dL; normal reference [NR]: 12.0–16.0), thrombocytopenia (78 × 109/L; NR: 150–450) and significant elevation of inflammatory markers (C-reactive protein, 301.0 mg/L; NR, <5; and procalcitonin, >100 ng/mL; NR, <0.1). No electrolyte disturbances, hypoglycemia, or acidosis. Plasmodium falciparum blood smear was positive, and severe malaria was diagnosed due to high parasitemia (28.5%/erythrocytes–11.872.000 parasites/µL) and central nervous system (CNS) involvement other infections were excluded. The cerebrospinal fluid revealed pleocytosis (15 cells), generalized slowing on the electroencephalogram, and a lesion in the splenium of the corpus callosum with T2 hypersignal and restricted diffusion (Fig. 1), compatible with a cytotoxic lesion of the corpus callosum (CLOCCs) on brain magnetic resonance imaging (MRI). CM was diagnosed based on severely impaired consciousness, CLOCCs, and no other identifiable causes of coma.FIGURE 1.: MRI axial images T2 weighted (A), DWI (B) and ADC map (C): oval lesion in the splenium of the corpus callosum (arrow) with T2 hypersignal and diffusion restriction with DWI hypersignal and ADC map hyposignal, corresponding to cytotoxic edema.The patient was treated with parenteral quinine and clindamycin, due to the immediate unavailability of artesunate, plus ceftriaxone. She became afebrile with progressive improvement in neurological status after 48 h and complete parasite clearance on day 3. Artemether-lumefantrine was initiated on day 5, and the patient was discharged on day 8. CM is defined as a disturbance of consciousness in a patient with Plasmodium parasitemia and no other identifiable cause.2 Despite the reported low mortality rate of pediatric imported malaria in Europe (<1%), CM entails a risk of life-threatening acute CNS effects with diffuse encephalopathy and often rapidly progressive coma, as observed in our patient.3 Distinctive brain MRI features involving both white and gray matter structures have been reported in a large cohort of Malawian children with CM. Increased volume, T2 hyperintensity, and Diffusion-weighted imaging (DWI) abnormalities affecting the cortical area (61.7%), subcortical and periventricular white matter (71.7%), basal ganglia (84.2%) and the corpus callosum (49.2%) were the most frequent features.4 CLOCCS was a common MRI finding in CM, as suggested by DWI/Apparent diffusion coefficient mismatch with DWI increased signal and Apparent diffusion coefficient low signal,4 as observed in our patient (Fig. 1). The corpus callosum, mostly the splenium, is a region vulnerable to inflammatory cytokinopathy, driven by malaria, seizures or other causes.5 The higher density of cytokines and glutamate receptors in this area leads to high extracellular glutamate levels, inducing cytotoxic edema upon infection, which is frequently reversible.5 CM in children is the most severe complication of P. falciparum infection and needs a high suspicion index in nonendemic countries. Altered MRI and CLOCCs, although unspecific, are associated with CM.

The clinical characteristics of neuronal intranuclear inclusion disease and its relation with inflammation.

Neuronal intranuclear inclusion disease (NIID) is a great imitator with a broad spectrum of clinical manifestations that include dementia, parkinsonism, paroxysmal symptoms, peripheral neuropathy, and autonomic dysfunction. Hence, it may also masquerade as other diseases such as Alzheimer's disease, Parkinson's disease, and Charcot-Marie-Tooth disease. Recent breakthroughs on neuroimaging, skin biopsy, and genetic testing have facilitated the diagnosis. However, early identification and effective treatment are still difficult in cases of NIID. To further study the clinical characteristics of NIID and investigate the relationship between NIID and inflammation. We systematically evaluated the clinical symptoms, signs, MRI and electromyographical findings, and pathological characteristics of 20 NIID patients with abnormal GGC repeats in the NOTCH2NLC gene. Some inflammatory factors in the patients were also studied. Paroxysmal symptoms such as paroxysmal encephalopathy, stroke-like episodes, and mitochondrial encephalomyopathy lactic acidosis and stroke (MELAS)-like episode were the most common phenotypes. Other symptoms such as cognitive dysfunction, neurogenic bladder, tremor, and vision disorders were also suggestive of NIID. Interestingly, not all patients showed apparent diffusion-weighted imaging (DWI) abnormality or intranuclear inclusions, while abnormal GGC repeats of NOTCH2NLC were seen in all patients. And fevers were noticed in some patients during encephalitic episodes, usually with increasing leukocyte counts and neutrophil ratios. Both IL-6 (p = 0.019) and TNF-α (p = 0.027) levels were significantly higher in the NIID group than in normal controls. Genetic testing of NOTCH2NLC may be the best choice in the diagnosis of NIID. Inflammation might be involved in the pathogenesis of NIID.

Clinical, radiological, and molecular analyses of neuronal intranuclear inclusion disease with polyglycine inclusions

Neuronal intranuclear inclusion disease (NIID) is a clinically complex neurological disorder that appears sporadically or autosomally. Expansions of intronic GGC trinucleotide repeats in the NOTCH2 N-terminal-like C (NOTCH2NLC) gene cause NIID. In this study, to clarify the clinical characteristics useful for the differential diagnosis of NIID, clinical data of neurological examination, neuroimaging, and nerve conduction studies of six NIID patients diagnosed by pathological or genetic investigations were analyzed. Clinically useful characteristics for diagnosing NIID include general hyporeflexia, episodic disturbance of consciousness, sensory disturbance, miosis, and dementia. Furthermore, neuroimaging findings, such as leukoencephalopathy in T2-weighted magnetic resonance imaging and a linear high intensity of subcortical U-fibers in diffusion-weighted imaging (DWI), as well as decreased motor nerve conduction velocity, are especially important biomarkers for NIID. However, it is necessary to remember that these features may not always be present, as shown in one of the cases who did not have a DWI abnormality in this study. This study also investigated whether expanded GGC repeats were translated into polyglycine. Immunohistochemical analysis using a custom antibody raised against putative C-terminal polypeptides followed by polyglycine of uN2CpolyG revealed that polyglycines were localized in the intranuclear inclusions in skin biopsy specimens from all six patients, suggesting its involvement in the pathogenesis of NIID.

Current advances in neuronal intranuclear inclusion disease.

Neuronal intranuclear inclusion disease (NIID) is a rare but probably underdiagnosed neurodegenerative disorder due to pathogenic GGC expansions in the NOTCH2NLC gene. In this review, we summarize recent developments in the inheritance features, pathogenesis, and histopathologic and radiologic features of NIID that subvert the previous perceptions of NIID. GGC repeat sizes determine the age of onset and clinical phenotypes of NIID patients. Anticipation may be absent in NIID but paternal bias is observed in NIID pedigrees. Eosinophilic intranuclear inclusions in skin tissues once considered pathological hallmarks of NIID can also present in other GGC repeat diseases. Diffusion-weighted imaging (DWI) hyperintensity along the corticomedullary junction once considered the imaging hallmark of NIID can frequently be absent in muscle weakness and parkinsonism phenotype of NIID. Besides, DWI abnormalities can appear years after the onset of predominant symptoms and may even disappear completely with disease progression. Moreover, continuous reports of NOTCH2NLC GGC expansions in patients with other neurodegenerative diseases lead to the proposal of a new concept of NOTCH2NLC-related GGC repeat expansion disorders (NRED). However, by reviewing the previous literature, we point out the limitations of these studies and provide evidence that these patients are actually suffering from neurodegenerative phenotypes of NIID.

The utility of diffusion-weighted imaging in patients with spinal cord infarction: difference from the findings of neuromyelitis optica spectrum disorder

BackgroundMagnetic resonance imaging (MRI) plays a crucial role in diagnosing spinal cord infarction (SCI). However, the findings are often indistinguishable from those of other intramedullary diseases, such as neuromyelitis optica spectrum disorder (NMOSD). Although diffusion-weighted imaging (DWI) is a promising technique, the utility for discriminating SCI from NMOSD remains unclear because the DWI findings of acute NMOSD lesions have not been investigated in detail.MethodsClinical and MRI findings were retrospectively evaluated in 15 and 12 patients with acute SCI and NMOSD, respectively. First, clinical characteristics were compared between the SCI and NMOSD groups. Second, MRI abnormalities were examined to find differences between these groups. Third, in the SCI group, factors influencing T2 and DWI abnormalities were analyzed using the mixed-effects logistic regression analysis.ResultsThe proportion of female patients was higher in the NMOSD group (92%) than in the SCI (40%). The time from symptom onset to nadir was smaller in the SCI group (median [interquartile range]; 4 [0.1–8.3] hours) than in the NMOSD (252 [162–576]). On T2-weighted images, SCI lesions had smaller length than NMOSD (2 [1–2] and 5 [2–7] vertebral segments, respectively). Focal lesions within the T9–L2 level were found only in patients with SCI. DWI hyperintensity was observed both in the SCI (frequency, 100%) and NMOSD (60%) groups. On apparent diffusion coefficient (ADC) maps, the hyperintensities of SCI had corresponding hypointensities, whereas those of NMOSD were isointense and a large portion of NMOSD lesions had hyperintense signals. Owl’s eyes sign and pencil-like hyperintensity, typically reported as T2 findings suggestive of SCI, were also found on DWI. Posterior linear hyperintensity was frequently detected on DWI in patients with posterior spinal artery infarction. The presence of MRI abnormality revealing SCI was modeled with the time from symptom onset, imaging sequence and plane, and affected vascular territory.ConclusionsDWI and ADC maps help distinguish SCI from NMOSD. The time from symptom onset, imaging sequence, and imaging plane should be considered when MRI findings are interpreted in patients with suspected SCI.

Shared and distinct white matter abnormalities in adolescent-onset schizophrenia and adolescent-onset psychotic bipolar disorder.

While adolescent-onset schizophrenia (ADO-SCZ) and adolescent-onset bipolar disorder with psychosis (psychotic ADO-BPD) present a more severe clinical course than their adult forms, their pathophysiology is poorly understood. Here, we study potentially state- and trait-related white matter diffusion-weighted magnetic resonance imaging (dMRI) abnormalities along the adolescent-onset psychosis continuum to address this need. Forty-eight individuals with ADO-SCZ (20 female/28 male), 15 individuals with psychotic ADO-BPD (7 female/8 male), and 35 healthy controls (HCs, 18 female/17 male) underwent dMRI and clinical assessments. Maps of extracellular free-water (FW) and fractional anisotropy of cellular tissue (FAT) were compared between individuals with psychosis and HCs using tract-based spatial statistics and FSL's Randomise. FAT and FW values were extracted, averaged across all voxels that demonstrated group differences, and then utilized to test for the influence of age, medication, age of onset, duration of illness, symptom severity, and intelligence. Individuals with adolescent-onset psychosis exhibited pronounced FW and FAT abnormalities compared to HCs. FAT reductions were spatially more widespread in ADO-SCZ. FW increases, however, were only present in psychotic ADO-BPD. In HCs, but not in individuals with adolescent-onset psychosis, FAT was positively related to age. We observe evidence for cellular (FAT) and extracellular (FW) white matter abnormalities in adolescent-onset psychosis. Although cellular white matter abnormalities were more prominent in ADO-SCZ, such alterations may reflect a shared trait, i.e. neurodevelopmental pathology, present across the psychosis spectrum. Extracellular abnormalities were evident in psychotic ADO-BPD, potentially indicating a more dynamic, state-dependent brain reaction to psychosis.

Neuronal intranuclear inclusion disease in patients with adult-onset non-vascular leukoencephalopathy.

Neuronal intranuclear inclusion disease (NIID), caused by an expansion of GGC repeats in the 5'-untranslated region of NOTCH2NLC, is an important but underdiagnosed cause of adult-onset leukoencephalopathies. The present study aimed to investigate the prevalence, clinical spectrum and brain MRI characteristics of NIID in adult-onset nonvascular leukoencephalopathies and assess the diagnostic performance of neuroimaging features. One hundred and sixty-one unrelated Taiwanese patients with genetically undetermined nonvascular leukoencephalopathies were screened for the NOTCH2NLC GGC repeat expansions using fragment analysis, repeat-primed PCR, Southern blot analysis and/or nanopore sequencing with Cas9-mediated enrichment. Among them, 32 (19.9%) patients had an expanded NOTCH2NLC allele and were diagnosed with NIID. We enrolled another two affected family members from one patient for further analysis. The size of the expanded NOTCH2NLC GGC repeats in the 34 patients ranged from 73 to 323 repeats. Skin biopsies from five patients all showed eosinophilic, p62-positive intranuclear inclusions in the sweat gland cells and dermal adipocytes. Among the 34 NIID patients presenting with nonvascular leukoencephalopathies, the median age at symptom onset was 61 years (range, 41-78 years) and the initial presentations included cognitive decline (44.1%; 15/34), acute encephalitis-like episodes (32.4%; 11/34), limb weakness (11.8%; 4/34) and parkinsonism (11.8%; 4/34). Cognitive decline (64.7%; 22/34) and acute encephalitis-like episodes (55.9%; 19/34) were also the most common overall manifestations. Two-thirds of the patients had either bladder dysfunction or visual disturbance. Comparing the brain MRI features between the NIID patients and individuals with other undetermined leukoencephalopathies, corticomedullary junction curvilinear lesions on diffusion weighted images were the best biomarkers for diagnosing NIID with high specificity (98.4%) and sensitivity (88.2%). However, this diffusion weighted imaging abnormality was absent in 11.8% of the NIID patients. When only fluid-attenuated inversion recovery images were available, the presence of white matter hyperintensity lesions either in the paravermis or middle cerebellar peduncles also favoured the diagnosis of NIID with a specificity of 85.3% and sensitivity of 76.5%. Among the MRI scans of 10 patients, performed within 5 days of the onset of acute encephalitis-like episodes, five showed cortical hyperintense lesions on diffusion weighted images and two revealed focal brain oedema. In conclusion, NIID accounts for 19.9% (32/161) of patients with adult-onset genetically undiagnosed nonvascular leukoencephalopathies in Taiwan. Half of the NIID patients developed encephalitis-like episodes with restricted diffusion in the cortical regions on diffusion weighted images at the acute stage. Corticomedullary junction hyperintense lesions, white matter hyperintensities in the paravermis or middle cerebellar peduncles, bladder dysfunction and visual disturbance are useful hints to diagnosing NIID.

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.

Seizure types associated with negative arterial spin labeling and positive diffusion-weighted imaging on peri-ictal magnetic resonance imaging

PurposeArterial spin labeling (ASL) and diffusion-weighted imaging (DWI) are useful for assessing hyperperfusion and cytotoxic edema, respectively, caused by acute seizures. This study investigated the clinical characteristics associated with normal ASL findings and DWI abnormalities in patients with acute seizures. MethodsOverall, 41 patients with ASL and DWI images that were obtained within 48 h of focal onset seizure diagnosis, due to epilepsy or acute symptomatic seizures, were divided into groups based on initial ASL findings (ASL-negative vs. ASL-positive), and DWI abnormalities (DWI-negative vs. DWI-positive). The diagnosis was made based on seizure semiology, electroencephalography, and conventional imaging modalities. ASL and DWI abnormalities were based on visual assessment. ResultsOf the 41 patients, eight (19.5%) displayed normal ASL findings. The proportion of patients with focal aware seizures (FAS) was significantly higher among ASL-negative patients (62.5%) than that in ASL-positive patients (15.2%); the proportion of patients with focal impaired awareness seizures (FIAS) was significantly lower among ASL-negative patients (12.5%) than that among ASL-positive patients (57.6%). Hyperintensity findings on DWI were observed in 12 patients (29.3%, DWI-positive). The proportion of patients with FIAS was significantly higher among DWI-positive patients (75.0%) than that among DWI-negative patients (37.9%). Multivariate analysis revealed that FAS and FIAS were associated with normal ASL findings (odds ratio [OR]: 21.37, P = 0.010) and DWI abnormalities (OR = 6.11, P = 0.028). ConclusionA diagnosis of seizures should not be excluded based on normal ASL findings, especially in patients with FAS. FIAS may be a risk factor for neuronal damage caused by seizure activity.

Spectrum of magnetic resonance abnormalities in leigh syndrome with emphasis on correlation of diffusion-weighted imaging findings with clinical presentation.

Leigh syndrome (LS) is a progressive neurodegenerative disorder of infancy/early childhood secondary to mitochondrial dysfunction. Imaging plays a pivotal role in the diagnosis of LS with certain typical magnetic resonance imaging (MRI) findings considered as a part of diagnostic criteria. We appraised various MRI findings on conventional MRI sequences and also assessed potential correlation between diffusion abnormalities and patient's clinical presentation. Our aim was to describe various patterns of central nervous system involvement in LS and to assess the correlation of diffusion-weighted imaging abnormalities with clinical presentation. The design of the study was retrospective comprising 8 children with LS who had MRI between years 2014 and 2019. Eight children between the age group of 4 months 8 years with LS based on clinical presentation, elevated lactate levels in CSF/Blood, and typical MRI findings were included in the study. Brainstem was involved all (100%) patients while basal ganglia was affected in 5 (62.5%) children. Cerebral white matter involvement was present in 3 (37.5%) children, cerebellar in 2 (25%) children while spinal, corpus callosum, and thalamic involvement were observed in one (12.5%) patient each. Diffusion restriction was observed in 6 children, all of them presented with altered sensorium. Conventional MRI serves as an excellent tool for the diagnosis of LS in children with clinical suspicion. Acute encephalopathy frequently presents with diffusion restriction corresponding to active lesions. Hence, diffusion restriction on MRI predicts the activity of lesions in patients with LS.

Abstract 13082: Region-Specific Diffusion-Weighted Imaging Predicts Neurological Outcome in Comatose Post-Cardiac Arrest Patients

Introduction &amp; Hypothesis: Diffusion-weighted imaging (DWI), a technique sensitive to acute brain ischemia, may hold utility in predicting neurological outcome in comatose post-cardiac arrest patients. Outcome studies are biased by early withdrawal of life sustaining therapy (WLST), leading to a self-fulfilling prophecy. This creates a need to reassess the use of DWI as a neuroprognostic tool in patients who have not undergone WLST. We hypothesize that DWI abnormalities is a robust predictor of poor neurological outcome in our WLST - controlled cohort. Methods: We leveraged the MOCHA database, a registry of over 300 comatose post-cardiac arrest patients, to retrospectively examine neurological outcomes in a cohort of patients who did not undergo WLST. A good outcome was defined by a cerebral performance category (CPC) score at discharge of 1 - 3, while a poor outcome CPC 4 - 5 (n=43). We first examined the relationship between the number of brain regions with DWI abnormalities and CPC score using a linear regression. We then examined how DWI abnormalities in specific brain regions correlated with CPC score outcome groups using a fisher exact test. DWI abnormalities were qualitatively determined by two vascular neurologists. Results: We found a positive correlation between the number of brain regions with DWI abnormalities and CPC score ( linear regression , R 2 =0.572, p=2.670x10 -9 ). Interestingly, the association between DWI abnormalities and CPC score exhibited brain region-specific variability. DWI abnormalities exhibited the strongest association with poor neurological outcome in the occipital lobe ( fisher exact test , p=7.413x10 -10 ), parietal lobe (p=9.125x10 -9 ), frontal lobe (p=5.385x10 -9 ), temporal lobe (p=3.904x10 -8 ) and basal ganglia (p=2.342x10 -7 ); and the weakest association in the white matter (p=1.000) and brain stem (p=6.612x10 -2 ). Conclusion: Our preliminary results suggest that the region of ischemia is an important factor to consider in predicting neurological outcome. This warrants a larger scale WLST-controlled study examining region-specific DWI abnormalities and neurological outcome - the findings of which would improve our neuroprognostication capabilities in comatose post-cardiac arrest patients.

Role of Apparent Diffusion Coefficient Gradient Within Diffusion Lesions in Outcomes of Large Stroke After Thrombectomy.

The outcome of endovascular treatment in stroke patients with a large ischemic core is not always satisfactory. We evaluated whether the severity of baseline diffusion-weighted imaging abnormalities, as assessed by different apparent diffusion coefficient (ADC) thresholds, correlates with the clinical outcome in these patients after successful endovascular treatment. In 82 consecutive patients with a large vessel occlusion in the anterior circulation admitted ≤24 hours after onset, a baseline diffusion lesion volume (ADC ≤620×10-6 mm2/s [ADC620]) ≥50 mL and successful recanalization by endovascular treatment were retrospectively investigated. Lesion volumes of 3 ADC thresholds (ADC620, ADC ≤520×10-6 mm2/s [ADC520], and ADC ≤540×10-6 mm2/s [ADC540]) were measured using an automated Olea software program. The performance of the ADC520/ADC620 and ADC540/ADC620 ratios in predicting the functional outcome was assessed by receiver operating characteristic curve analysis. The ADC ratio with optimal threshold showing better receiver operating characteristic performance was dichotomized at its median value into low versus high subgroup and its association with the outcome subsequently evaluated in a multivariable logistic regression model. The median baseline diffusion lesion volume was 80.8 mL (interquartile range, 64.4-105.4). A good functional outcome (modified Rankin Scale score, ≤2) was achieved in 35 patients (42.7%). The optimal threshold for predicting the functional outcome was identified as ADC540/ADC620 (area under the curve, 0.833) and dichotomized at 0.674. After adjusting for age, baseline National Institutes of Health Stroke Scale score, intravenous tissue-type plasminogen activator, baseline diffusion lesion volume, and onset-to-recanalization time, a low ADC540/ADC620 was independently associated with a good functional outcome (adjusted odds ratio, 10.72 [95% CI, 3.06-37.50]; P<0.001). A low ADC540/ADC620, which may reflect less severe ischemic stress inside a diffusion lesion, may help to identify patients who would benefit from endovascular treatment despite having a large ischemic core.

Potential of machine learning to predict early ischemic events after carotid endarterectomy or stenting: a comparison with surgeon predictions.

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are recommended for high stroke-risk patients with carotid artery stenosis to reduce ischemic events. However, we often face difficulty in determining the best treatment strategy. We aimed to develop an accurate post-CEA/CAS outcome prediction model using machine learning that will serve as a basis for a new decision support tool for patient-specific treatment planning. Retrospectively collected data from 165 consecutive patients with carotid stenosis underwent CEA or CAS and were divided into training and test samples. The following five machine learning algorithms were tuned, and their predictive performance was evaluated by comparison with surgeon predictions: an artificial neural network, logistic regression, support vector machine, random forest, and extreme gradient boosting (XGBoost). Seventeen clinical factors were introduced into the models. Outcome was defined as any ischemic stroke within 30days after treatment including asymptomatic diffusion-weighted imaging abnormalities. The XGBoost model performed the best in the evaluation; its sensitivity, specificity, positive predictive value, and accuracy were 31.9%, 94.6%, 47.2%, and 86.2%, respectively. These statistical measures were comparable to those of surgeons. Internal carotid artery peak systolic velocity, low-density lipoprotein cholesterol, and procedure (CEA or CAS) were the most contributing factors according to the XGBoost algorithm. We were able to develop a post-procedural outcome prediction model comparable to surgeons in performance. The accurate outcome prediction model will make it possible to make a more appropriate patient-specific selection of CEA or CAS for the treatment of carotid artery stenosis.