Inversion Recovery Images Research Articles

Characterizing T1 in the fetal brain and placenta over gestational age at 0.55T.

T1 mapping and T1-weighted contrasts have a complimentary but currently under utilized role in fetal MRI. Emerging clinical low field scanners are ideally suited for fetal T1 mapping. The advantages are lower T1 values which results in higher efficiency and reduced field inhomogeneities resulting in a decreased requirement for specialist tools. In addition the increased bore size associated with low field scanners provides improved patient comfort and accessibility. This study aims to demonstrate the feasibility of fetal brain T1 mapping at 0.55T. An efficient slice-shuffling inversion-recovery echo-planar imaging (EPI)-based T1-mapping and postprocessing was demonstrated for the fetal brain at 0.55T in a cohort of 38 fetal MRI scans. Robustness analysis was performed and placental measurements were taken for validation. High-quality T1 maps allowing the investigation of subregions in the brain were obtained and significant correlation with gestational age was demonstrated for fetal brain T1 maps ( ) as well as regions-of-interest in the deep gray matter and white matter. Efficient, quantitative T1 mapping in the fetal brain was demonstrated on a clinical 0.55T MRI scanner, providing foundations for both future research and clinical applications including low-field specific T1-weighted acquisitions.

Quantitative molecular imaging of cardiac fibrosis and response to treatment using a novel collagen III-specific MR imaging probe

Abstract Background Heart failure (HF) remains a major cause of morbidity and death affecting 64 million people globally[1]. Myocardial fibrosis, characterised by changes in type I (COL1) and III (COL3) collagen levels, may lead to HF [2,3]. Cardiac magnetic resonance (CMR) is a preferred method to detect fibrosis non-invasively, however it provides only indirect measures of fibrosis. Molecular imaging can directly visualise fibrosis, but current imaging probes target COL1. Purpose Here, we developed a COL3-specific probe and used molecular CMR imaging to directly quantify, previously undetectable, COL3 remodelling following myocardial infarction and to monitor treatment response. Methods Myocardial infarction (MI) was induced in mice by permanent ligation of the left anterior descending artery (LAD). Functional and molecular CMR images were acquired at days 10 and 21 post-MI in untreated and mice treated with Enalapril (20mg/kg/day) (n=6/group) using a 3T clinical MRI scanner. A subgroup of untreated mice was also imaged using a negative control probe and Gadovist (n=3). Cardiac function was assessed using 2D short-axis cine images of the left ventricle, and late gadolinium enhancement (LGE) images were obtained using T1-weighted 3D inversion recovery (IR) imaging. T1 mapping was performed using a 2D Look-Locker sequence with thirty inversion recovery images. Results Molecular CMR enabled selective profiling of the natural turnover of COL3 after MI with strong signal enhancement at day 10, and decreased enhancement at day 21 when COL3 is replaced by COL1 (Fig. 1A). Quantitative T1 maps discriminated between infarcted and remote myocardium with lower T1 values in the infarct and higher in the remote myocardium. Importantly, there was no enhancement using the scrambled probe or the clinical agent Gadovist. The imaging data were validated by histology (Fig.1B). Mice treated with Enalapril showed similar enhancement at day 10 compared to untreated mice (Fig. 2A). However, at day 21 mice treated with Enalapril showed higher signal enhancement compared to untreated mice, suggesting that Enalapril may prolong the presence of COL3 in the infarcted myocardium. Quantification of signal enhancement showed the increase in LGE volume and R1 relaxation rates within the infarcted myocardium at day 10, the subsequent decrease at day 21 and the prolongation of the COL3 signal at day 21 in enalapril treated mice (Fig.2B-C) Despite changes in cardiac fibrosis detected with molecular imaging, cardiac function was similar between the groups (Fig. 2D), suggesting that molecular change may precede functional changes. Conclusion(s) Quantitative molecular CMR imaging of COL3 enabled visualisation of changes in COL3 after MI and in response to treatment for the first time. This approach may provide insights into the role of COL3 in cardiac fibrosis and provide an non-invasive method to detect fibrosis early, stage fibrosis and monitor therapeutic response.

SDS-Net: A Synchronized Dual-Stage Network for Predicting Patients Within 4.5-h Thrombolytic Treatment Window Using MRI.

Timely and precise identification of acute ischemic stroke (AIS) within 4.5h is imperative for effective treatment decision-making. This study aims to construct a novel network that utilizes limited datasets to recognize AIS patients within this critical window. We conducted a retrospective analysis of 265 AIS patients who underwent both fluid attenuation inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) within 24h of symptom onset. Patients were categorized based on the time since stroke onset (TSS) into two groups: TSS ≤ 4.5 h and TSS > 4.5 h. The TSS was calculated as the time from stroke onset to MRI completion. We proposed a synchronized dual-stage network (SDS-Net) and a sequential dual-stage network (Dual-stage Net), which were comprised of infarct voxel identification and TSS classification stages. The models were trained on 181 patients and validated on an independent external cohort of 84 patients using metrics of area under the curve (AUC), sensitivity, specificity, and accuracy. A DeLong test was used to statistically compare the performance of the two models. SDS-Net achieved an accuracy of 0.844 with an AUC of 0.914 in the validation dataset, outperforming the Dual-stage Net, which had an accuracy of 0.822 and an AUC of 0.846. In the external test dataset, SDS-Net further demonstrated superior performance with an accuracy of 0.800 and an AUC of 0.879, compared to the accuracy of 0.694 and AUC of 0.744 of Dual-stage Net (P = 0.049). SDS-Net is a robust and reliable tool for identifying AIS patients within a 4.5-h treatment window using MRI. This model can assist clinicians in making timely treatment decisions, potentially improving patient outcomes.

MELAS Presenting as Bilateral Symmetric Occipital and Temporal Cortices Lesions: A Case Report and Literature Review.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS) is one of the most common maternally inherited mitochondrial diseases. The stroke-like episode affecting the cortical cortex is the hallmark of MELAS; however, it rarely presents as simultaneously bilateral symmetric cortices lesions. We reported a case of MELAS in a 46-year-old female patient with bilateral symmetric occipital and internal temporal cortices involvements on brain magnetic resonance imaging (MRI). A literature review of MELAS patients and a retrospective analysis were performed. She had a family history of diabetes. Although she denied a history of diabetes, elevated blood glucose was noted after admission, and diabetes was diagnosed. Laboratory examination revealed elevated lactate acid and creatine kinase levels in blood. Cranial computed tomography (CT) image demonstrated basal ganglia calcification, as well as subtle decreased attenuation in bilateral symmetric occipital and internal temporal cortices. Brain magnetic resonance imaging (MRI) demonstrated symmetric gyriform hyperintensity in bilateral occipital lobes and internal temporal lobes in both grey and white matter on fluid-attenuated inversion recovery (FLAIR) images with restricted diffusion on diffusion weighted images (DWI). A genetic test revealed a point mutation in the mtDNA(3243A > G) by blood examination. Literature review showed that there were 231 eligible patients with MELAS identified from 212 published papers. Symmetric cortical involvements were seen in 15 (6.5%) patients on brain MRI. MELAS should be considered as a potential diagnosis in the patients with bilateral symmetric stroke-like cortices lesions.

Synthetic double inversion recovery imaging for rectal cancer T staging evaluation: imaging quality and added value to T2-weighted imaging

ObjectiveTo assess the image quality of synthetic double inversion recovery (SyDIR) imaging and enhance the value of T2-weighted imaging (T2WI) in evaluating T stage for rectal cancer patients.MethodsA total of 112 pathologically confirmed rectal cancer patients were retrospectively selected after undergoing MRI, including synthetic MRI. The image quality of T2WI and SyDIR imaging was compared based on signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), overall picture quality, presence of motion artifacts, lesion edge sharpness, and conspicuity. The concordance between MRI and pathological staging results, using T2WI alone and the combination of T2WI and SyDIR for junior and senior radiologists, was assessed using the Kappa test. The area under the receiver operating characteristic curve (AUC) was used to assess the diagnostic efficacy of extramural infiltration in rectal cancer patients.ResultsNo significant differences in imaging quality were observed between conventional T2WI and SyDIR (p = 0.07–0.53). The combination of T2WI and SyDIR notably improved the staging concordance between MRI and pathology for both junior (kappa value from 0.547 to 0.780) and senior radiologists (kappa value from 0.738 to 0.834). In addition, the integration of T2WI and SyDIR increased the AUC for diagnosing extramural infiltration for both junior (from 0.842 to 0.918) and senior radiologists (from 0.917 to 0.938).ConclusionThe combination of T2WI and SyDIR increased the consistency of T staging between MRI and pathology, as well as the diagnostic performance of extramural infiltration, which would benefit treatment selection.Critical relevance statementSyDIR sequence provides additional diagnostic value for T2WI in the T staging of rectal cancer, improving the agreement of T staging between MRI and pathology, as well as the diagnostic performance of extramural infiltration.Key PointsSynthetic double inversion recovery (SyDIR) and T2WI have comparable image quality.SyDIR provides rectal cancer anatomical features for extramural infiltration detections.The combination of T2WI and SyDIR improves the accuracy of T staging in rectal cancer.Graphical

CLCN2-related leukoencephalopathy with novel compound heterozygous variants followed with magnetic resonance imaging over 17 years: a case report

BackgroundCLCN2-related leukoencephalopathy (CC2L) is a rare autosomal recessive disorder caused by biallelic variants of CLCN2, which encodes chloride channel 2. Although CC2L is associated with distinct radiological features, it presents with a wide range of clinical features.Case presentationA 34-year-old woman presented to our hospital with a sudden onset of vertigo with headache. The patient reported intermittent headaches and tingling in both arms since the age of 31 years. On the first visit, the patient was alert and neurologically intact, except for slight hyperreflexia of the limbs without laterality. Head magnetic resonance imaging (MRI) showed high-intensity signals on axial T2-weighted fluid-attenuated inversion recovery and diffusion-weighted images bilaterally in the posterior limbs of the internal capsules, cerebral peduncles, superior and middle cerebellar peduncles, decussation of superior cerebellar peduncles, and central tegmental tract. All the patient’s symptoms were resolved or eased following supportive care. The patient stopped attending our hospital at the age of 46 years. At 51 years of age, the patient revisited our hospital because of the recurrence of vertigo, headache, and nausea. She did not present with any abnormalities by neurological examination. Head MRI showed widespread high-intensity signals similar to those 17 years ago. Genetic testing revealed compound heterozygous variants in CLCN2 (NM_004366.6): a novel variant c.1828 C > T, p.(Arg 610*) from her father and c.61dup, p.(Leu21Profs*27) from her mother. The patient was finally diagnosed with CC2L. She received supportive treatment, which made her symptoms manageable.ConclusionsThis is a detailed report of a patient with adult-onset CC2L who was successfully diagnosed and followed up with head MRI. This report provides new insights into CC2L and highlights its persistent, distinct, and stable characteristics observed in head MRI over one decade and the difficulty in forming a diagnosis without MRI when patients have minimal and common symptoms, such as in the present case.

Poor venous outflow is associated with hyperintense acute reperfusion marker on follow-up MRI in patients with acute ischemic stroke with a large vessel occlusion

BackgroundHyperintense acute reperfusion marker (HARM) refers to delayed enhancement in the subarachnoid or subpial space on post-contrast fluid attenuated inversion recovery (FLAIR) images. HARM is a measure of blood–brain barrier...

Role of Magnetic Resonance Spectroscopy and Diffusion-weighted Imaging in the Evaluation of Supratentorial Brain Tumours with Histopathology Correlation at a Tertiary Care Hospital: An Observational Study

Abstract Background: Traditional magnetic resonance imaging (MRI) may face challenges in accurately discerning supratentorial malignancies. However, advanced techniques such as diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) have significantly enhanced diagnostic accuracy. Thus, the study aimed to evaluate the effectiveness of these non-invasive diagnostic methods in patients with suspected intracranial lesions. Materials and Methods: In this prospective observational study at Osmania General and Allied Hospitals, 40 eligible patients were enrolled. After applying the inclusion and exclusion criteria, MRI examinations were conducted at two hospitals utilising GE 1.5T and PHILIPS 1.5T 32-channel machines. Standardised brain sequences, encompassing T1- and T2-weighted scans, DWI, gradient-recalled echo and fluid-attenuated inversion recovery imaging, were systematically performed. In addition, post-contrast administration and contrast-enhanced MRS were employed. Results: In this study, a higher tumour incidence was observed in males (52%) compared to females (48%). The choline/creatine (CHO/Cr) ratio revealed more cases below 1.5 and fewer at the 3.1–3.5 level. Perilesional CHO/Cr ratio had the highest cases (21) at 1.1–2.0 and the lowest (2) at 3.1–4.0. Further analysis revealed significant differences in the mean CHO/Cr ratio amongst primary low-grade (1.8), primary high-grade (3.91) and metastatic tumours (7.23). The mean choline/N-acetyl aspartate (NAA) ratio also differed significantly amongst these tumour types, with choline/NAA and CHO/Cr ratios indicating statistical significance in distinguishing primary low-grade tumours. In addition, mean apparent diffusion coefficient values showed significant differences between primary low-grade tumours (1.1), primary high-grade tumours (0.87) and metastasis (0.855). Conclusion: This study underscores gender-related differences in supratentorial tumour susceptibility and highlights distinct tumour distributions based on grades. These findings emphasise the significance of considering gender, age and histopathological attributes when evaluating supratentorial tumours.

Acute necrotizing encephalopathy caused by bacterial infection

PurposeAcute necrotizing encephalopathy (ANE), a rare and severe brain disorder, is typically linked to prior infections. ANE predominantly affects children, with most reported cases attributed to viral infections. However, instances of bacterial-induced ANE are infrequent. Here, we present a case of adult-onset ANE associated with bacterial infection.Case descriptionsThe patient exhibited a hyperinflammatory state following a urinary tract bacterial infection, with neurological function rapidly declining into a coma as the illness progressed. Gram culture of blood suggested Escherichia coli infection. A magnetic resonance imaging (MRI) scan of the brain showed symmetrical hyperintense lesions involving bilateral thalami and pons in T2-weighted and fluid-attenuated inversion recovery images. These lesions also presented with diffuse cerebral edema and diffusion restriction and subacute hemorrhage. Based on clinical symptoms and typical brain MRI, ANE was diagnosed, and the patient underwent immunotherapy.ConclusionsThis case underscores the occurrence of ANE triggered by bacterial infection, expanding our understanding of the pathogens associated with this condition. It suggests that ANE may be an immune-mediated disorder rather than solely an infectious disease.

Effects of Goreisan in the Perioperative Period of Subthalamic Deep Brain Stimulation in Parkinson's Disease.

Patients with Parkinson's disease (PD) may benefit from deep brain stimulation (DBS). Perifocal brain edema sometimes occurs after DBS surgery, but it is transient and does not affect the final prognosis. Transient deterioration of cognitive function has been reported in patients with frontal edema in the first postoperative week. This study aimed to investigate the effect of Goreisan in preventing edematous changes after DBS and determine the influence of edema on cognition. We included 29 patients with PD who underwent bilateral subthalamic nucleus (STN) DBS and who were divided into 2 groups: those using (11 patients) and those not using Goreisan (18 patients). At 1 week postoperatively, all patients underwent magnetic resonance imaging. We measured the volume of edema either in the frontal white matter or STN on fluid-attenuated inversion recovery (FLAIR) images. Finally, brain edema, motor function, and cognitive function were compared between the groups with and without Goreisan. In the FLAIR image 1 week postoperatively, the average postoperative frontal subcortical edema (FE) volume of the group with Goreisan was significantly lower than that without Goreisan (2249±2186mm3, 6261±7213mm3, respectively, p=0.023). Multivariate analysis with age, preoperative Mini-Mental State Examination (MMSE) score, FE, and peri-STN edema (SE) as factors, and MMSE at 1 week postoperatively as the dependent variable showed that preoperative MMSE score and SE were significant as associated factors. FE after DBS surgery may be alleviated using Goreisan. SE and preoperative MMSE scores were associated with MMSE scores 1 week postoperatively. Not applicable.

Subtypes and location of (juxta)cortical lesions relate to cognitive dysfunction in people with multiple sclerosis

Background: Cortical lesion subtypes’ occurrence and distribution across networks may shed light on cognitive impairment (CI) in multiple sclerosis (MS). Methods: In 332 people with MS, lesions were classified as intracortical, leukocortical or juxtacortical based on artificially generated double inversion-recovery images. Results: CI-related leukocortical lesion count increases were greatest within sensorimotor and cognitive networks (p < 0.001). Only intracortical lesion count could distinguish between cognitive groups (p = 0.024). Effect sizes were two- to four-fold larger than differences between MS phenotypes. Conclusion: In CI-MS, leukocortical lesions predominate, whereas intracortical lesions distinguish cognitive groups. Lesions’ grey matter (GM) involvement might be decisive for cognition in MS, surpassing overall disease burden.

Specialized gray matter segmentation via a generative adversarial network: application on brain white matter hyperintensities classification.

White matter hyperintensities (WMH) observed in T2 fluid-attenuated inversion recovery (FLAIR) images have emerged as potential markers of neurodegenerative diseases like Multiple Sclerosis (MS). Lacking comprehensive automated WMH classification systems in current research, there is a need to develop accurate detection and classification methods for WMH that will benefit the diagnosis and monitoring of brain diseases. Juxtacortical WMH (JCWMH) is a less explored subtype of WMH, primarily due to the hard definition of the cortex in FLAIR images, which is escalated by the presence of lesions to obtain appropriate gray matter (GM) masks. In this study, we present a method to perform a specialized GM segmentation developed for the classification of WMH, especially JCWMH. Using T1 and FLAIR images, we propose a pipeline to integrate masks of white matter, cerebrospinal fluid, ventricles, and WMH to create a unique mask to refine the primary GM map. Subsequently, we utilize this pipeline to generate paired data for training a conditional generative adversarial network (cGAN) to substitute the pipeline and reduce the inputs to only FLAIR images. The classification of WMH is then based on the distances between WMH and ventricular and GM masks. Due to the lack of multi-class labeled WMH datasets and the need for extensive data for training deep learning models, we attempted to collect a large local dataset and manually segment and label some data for WMH and ventricles. In JCWMH classification, the proposed method exhibited a Dice similarity coefficient, precision, and sensitivity of 0.76, 0.69, and 0.84, respectively. With values of 0.66, 0.55, and 0.81, the proposed method clearly outperformed the approach commonly used in the literature, which uses extracted GM masks from registered T1 images on FLAIR. After training, the method proves its efficiency by providing results in less than one second. In contrast, the usual approach would require at least two minutes for registration and segmentation alone. The proposed method is automated and fast and requires no initialization as it works exclusively with FLAIR images. Such innovative methods will undoubtedly facilitate accurate and meaningful analysis of WMH in clinical practice by reducing complexity and increasing efficiency.

Characterization of Classic Meningioma with Use of Conventional Magnetic Resonance and Diffusion Tensor Imaging

Introduction: The conventional magnetic resonance imaging (MRI) method is widely considered ‘with limited success’ in differentiating the meningioma types but may fail to localize the tumor occupation of white-matter fiber bundles accurately. Diffusion tensor imaging (DTI) is considered as an imaging modality that may elucidate the microstructure of brain tumors. We provide characteristics of meningioma using DTI-based-three-dimensional tracing of white matter to portray meningioma in a noninvasive approach and its structural contact to contiguous tumors and elucidate the influence of occupying lesions on white-matter fiber bundles. Case Presentation: A 28-year-old female presented with visuospatial disturbances and persistent headaches for 2 years. Conventional and advanced MRI studies were performed. Diffusion-weighted Images (DWI) and Apparent Diffusion Coefficient (ADC) values were measured in the lesion using routine MRI sequences. Advanced MRI using DTI was also performed. Conventional MRI outcomes showed tumor parenchyma, peritumoral edema, and compression on the circumnavigated brain tissue. There was hyperintense on DW trace image and isointense on ADC map. On T2-weighted image (T2WI) and Fluid-Attenuated Inversion Recovery (FLAIR) images, there was an increased signal intensity that demonstrated an extra-axial lesion, while T1-weighted imaging signals showed hypointensity. DTI fractional anisotropy (FA) marker is an unclear optic radiation in the concerned area, indicating the shift or destruction of the optic radiation. The mean FA values of solid-enhancing areas of meningioma were 0.28 ± 0.17. Mean ADC values (103 mm2/s) were 0.764 ± 0.172. Conclusions: Classic meningioma in this case has low intratumoral FA and high ADC. DTI displayed that intratumoral microscopic water motion is disorganized.

Structural and functional brain markers of cognitive impairment in healthcare workers following mild SARS-CoV-2 infection during the original stream.

Severe acute respiratory syndrome coronavirus 2 infection often involves the nervous system, leading to cognitive dysfunctions, fatigue and many other neurological signs that are becoming increasingly recognized. Despite mild forms of the disease accounting for most cases worldwide, research on the pathophysiology driving mild coronavirus disease 2019 (COVID-19) has received little attention. In this respect, recent evidence has pointed out that around 30-40% of non-critical, mild-to-moderate severity COVID-19 survivors may display cognitive disturbances several months post-illness. Hence, the impact of COVID-19 on the brain structure and function, through potential neuropathological mechanisms underpinning cognitive alterations in post-mild COVID-19 infections, remains largely unexplored. This retrospective multicentre observational cohort study, entirely based on a healthcare worker sample (n = 65; 55% females, aged 21-61), investigated the cognitive status and the structural and functional brain integrity among non-hospitalized individuals who developed mild COVID-19 symptoms during the occurrence of severe acute respiratory syndrome coronavirus 2 variants Alpha to Delta, compared with healthy controls tested before the pandemic onset. All evaluations were performed at an average of 9-month follow-up post-infection period. Participants completed a comprehensive neuropsychological assessment and structural and functional MRI exams. Radiological inspection sought to detect the presence of white matter hyperintensities on axial fluid-attenuated inversion recovery images. Global and regional grey matter integrity assessment, analysing changes in grey matter volumes and cortical thinning, and functional connectivity alterations of resting-state brain networks were also conducted. Regression analyses tested the relationships between the presence of specific cognitive impairments and potential structural and functional brain findings. Our results revealed that clinical, cognitive screening and neuropsychological examinations were average between both groups, except for specific impairments related to executive functions in the mild COVID-19. Compared to healthy controls, mild COVID-19 subjects exhibited increased juxtacortical white matter hyperintensities, thalamic and occipital volume loss and diminished resting-state functional connectivity involving the left precuneus and cuneus in default-mode network and affecting the right angular gyrus and left precuneus in the dorsal attentional network. Reduced thalamic volume was the only variable selected in the final model explaining the observed executive function impairment in mild COVID-19. The presence of cognitive, structural and functional brain abnormalities over time suggests that the action of widespread neurovascular and inflammatory phenomena on the nervous system might also occur in mild forms following COVID-19 infection rather than permanent brain damage linked to the direct or indirect action of the virus. Our findings emphasize the need to pay attention to the long-term brain-related consequences of mild COVID-19 infections during the original stream.

Awake Surgery for Right Frontal Lobe Glioma: Preserving Emotional Recognition and Facilitating Early Return to Work.

Many glioma patients struggle to return to work after surgery because of higher brain dysfunction. Although the right frontal lobe has historically been considered functionally silent, reports of performing awake surgery to evaluate higher brain functions in patients with tumors in this area have increased. We present two cases of patients who underwent awake surgery for malignant glioma in the right frontal lobe to preserve emotional recognition and facilitate an early return to work. Case 1 was a 48-year-old right-handed woman employed as a nursery school teacher and case 2 was a 21-year-old right-handed man employed in sales. Both had contrast-enhancing right frontal lobe tumors exhibiting high signal intensity on fluid attenuated inversion recovery imaging and underwent awake surgery. During the operation, cortical mapping was performed using the Reading the Mind in the Eyes, calculation, and motor tasks. Resection of sites involved in motor and emotional recognition functions was avoided. In case 1, all regions of high signal intensity were completely resected; in case 2, all regions exhibiting enhancement were resected. Both patients were discharged home without neurological deficits and returned to work within 21 days after surgery. It may be important to focus not only on overall survival and progression-free survival in glioma patients, but also on factors associated with life satisfaction, such as time to return to work after surgery and time until work becomes difficult. Awake surgery aimed at preserving higher brain functions is useful and may also improve life satisfaction.

Cross-Modality Image Translation From Brain 18 F-FDG PET/CT Images to Fluid-Attenuated Inversion Recovery Images Using the CypixGAN Framework.

PET/CT and MRI can accurately diagnose dementia but are expensive and inconvenient for patients. Therefore, we aimed to generate synthetic fluid-attenuated inversion recovery (FLAIR) images from 18 F-FDG PET and CT images of the human brain using a generative adversarial network (GAN)-based deep learning framework called the CypixGAN, which combined the CycleGAN framework with the L1 loss function of the pix2pix. Data from 143 patients who underwent PET/CT and MRI were used for training (n = 79), validation (n = 20), and testing (n = 44) the deep learning frameworks. Synthetic FLAIR images were generated using the pix2pix, CycleGAN, and CypixGAN, and white matter hyperintensities (WMHs) were then segmented. The performance of CypixGAN was compared with that of the other frameworks. The CypixGAN outperformed the pix2pix and CycleGAN in generating synthetic FLAIR images with superior visual quality. Peak signal-to-noise ratio and structural similarity index (mean ± standard deviation) estimated using the CypixGAN (20.23 ± 1.31 and 0.80 ± 0.02, respectively) were significantly higher than those estimated using the pix2pix (19.35 ± 1.43 and 0.79 ± 0.02, respectively) and CycleGAN (18.74 ± 1.49 and 0.78 ± 0.02, respectively) ( P < 0.001). WMHs in synthetic FLAIR images generated using the CypixGAN closely resembled those in ground-truth images, as indicated by the low absolute percentage volume differences and high dice similarity coefficients. The CypixGAN generated high-quality FLAIR images owing to the preservation of spatial information despite using unpaired images. This framework may help improve diagnostic performance and cost-effectiveness of PET/CT when MRI scan is unavailable.

Increased extracellular free water is related to white matter hyperintensity burden.

Extracellular free water (FW) has important roles in the occurrence and development of white matter hyperintensity (WMH). To explore the correlations between FW and WMH burden. A prospective analysis was conducted using magnetic resonance imaging (MRI) data from 126 individuals. WMH burden was determined based on WMH volumes and Fazekas scores from deep and periventricular white matter hyperintensity (DWMH and PWMH, respectively) in fluid-attenuated inversion recovery (FLAIR) images. FW values were taken from diffusion tensor imaging (DTI). Univariate analysis showed that FW values were correlated with WMH burden, including WMH volumes and DWMH and PWMH Fazekas scores (P < 0.05). After multivariate analysis, FW values were correlated with WMH volumes and DWMH and PWMH Fazekas scores when adjusted for age and hypertension (P < 0.05). Using MRI, increasing extracellular FW was related to WMH burden.

Evaluation of Inflammatory Disease Activity in the Sacroiliac Joints Using Magnetic Resonance Imaging: A Comparative Analysis of Short-Tau Inversion Recovery, Post-Contrast, and Diffusion-Weighted Imaging –Preliminary Study

Introduction: It is essential to detect sacroiliitis earlier to decrease morbidity and unwanted complications such as ankylosing of sacroiliac joints. In recent studies, magnetic resonance imaging (MRI) serves as a key diagnostic tool for identifying sacroiliitis and is now included in the diagnostic criteria. We aim to detect the utility of diffusion-weighted imaging on the MRI in diagnosing sacroiliitis and measure ADC values for the response to treatment in future studies. Materials -methods: There were 39 patients (16 male, 20 female). A 1.5 Tesla MR device with a pelvic coil was used. The sequences were T1 (before and after intravenous contrast administration of gadolinium), T2-weighted fast field echo, short tau inversion recovery (STIR), diffusion-weighted (DW) images, and apparent diffusion coefficient (ADC) mapping. Sacroiliac joints were divided into four quadrants, and two radiologists interpreted all the sequences by giving scores from 0 to 3 depending on bone marrow edema from none to severe. The concordance of scores assigned to STIR, T1-weighted gadolinium-enhanced images, ADC mapping, and diffusion-weighted MR images was evaluated by calculating intraclass correlation coefficients. Results: A statistically significant positive correlation was observed between the activity scores derived from short tau inversion recovery (STIR) and other magnetic resonance (MR) sequences, namely T1-weighted gadolinium-enhanced images, apparent diffusion coefficient (ADC) mapping, and diffusion-weighted MR images. Conclusion: Active bone marrow abnormalities were identified with comparable efficacy using STIR imaging and other MR sequences (T1W-Gad, ADC mapping, DW-MR). In our study, we tried to emphasize the role of the diffusion-weighted images near the other sequences. Diffusion is a fast, easy-applied sequence. After increased experience in the diffusion-weighted images, routine application of this sequence will increase, and even becoming one of the diagnostic criteria will be inevitable. The difference in DWI from the other sequences is that it is measurable. The response to treatment may be followed up by ADC values.

Prediction of Glioma enhancement pattern using a MRI radiomics-based model.

Contrast-MRI scans carry risks associated with the chemical contrast agents. Accurate prediction of enhancement pattern of gliomas has potential in avoiding contrast agent administration to patients. This study aimed to develop a machine learning radiomics model that can accurately predict enhancement pattern of gliomas based on T2 fluid attenuated inversion recovery images. A total of 385 cases of pathologically-proven glioma were retrospectively collected with preoperative magnetic resonance T2 fluid attenuated inversion recovery images, which were divided into enhancing and non-enhancing groups. Predictive radiomics models based on machine learning with 6 different classifiers were established in the training cohort (n = 201), and tested both in the internal validation cohort (n = 85) and the external validation cohort (n = 99). Receiver-operator characteristic curve was used to assess the predictive performance of these radiomics models. This study demonstrated that the radiomics model comprising of 15 features using the Gaussian process as a classifier had the highest predictive performance in both the training cohort and the internal validation cohort, with the area under the curve being 0.88 and 0.80, respectively. This model showed an area under the curve, sensitivity, specificity, positive predictive value and negative predictive value of 0.81, 0.98, 0.61, 0.82, 0.76 and 0.96, respectively, in the external validation cohort. This study suggests that the T2-FLAIR-based machine learning radiomics model can accurately predict enhancement pattern of glioma.

Unusual MRI abnormality in patients with nonketotic hyperglycaemia-associated seizures

Abstract Nonketotic hyperglycaemia (NKH) is a metabolic disorder typically observed in individuals with inadequately managed or undiagnosed diabetes mellitus (DM). Seizures are a common clinical presentation in NKH, and they tend to respond better to glucose correction than anticonvulsant therapy. MRI scans may reveal both subcortical T2/fluid-attenuated inversion recovery (FLAIR) imaging hypointensity and cortical changes, including cortical grey matter T2/FLAIR imaging hyperintensity and cortical or leptomeningeal enhancement, although cortical abnormalities are less frequently observed. These alterations are reversible when the underlying metabolic disturbance is effectively addressed. We suggest the role of iron accumulation as a mechanism for subcortical T2 hypointensity using T2* weighted imaging. Our cases substantiate the significance of subcortical T2/FLAIR hypointensity as a fundamental feature of this condition. In the appropriate clinical context, the recognition of these MRI abnormalities can help prevent misdiagnosis and facilitate timely treatment.