Attenuated Inversion Recovery Magnetic Resonance Research Articles

Associations Between Cardiac Function and Brain Health in Diverse Middle-Aged Adults: The Dallas Heart Study-2

BackgroundPrevious studies have linked cardiovascular risk factors during midlife to cognitive function in later life. However, few studies have looked at the association between cardiac function, brain structure, and cognitive function and even less have included diverse middle-aged populations. ObjectivesThe objective of this study was to determine associations between cardiac and brain structure and function in a multiethnic cohort of middle-aged adults. MethodsA cross-sectional study was conducted in participants of the Dallas Heart Study phase 2 (N = 1,919; 46% Black participants). Left ventricular (LV) mass, LV ejection fraction, LV concentricity, and peak systolic strain (LV Ecc) were assessed by cardiac magnetic resonance imaging. White matter hyperintensities (WMH) volume was measured by fluid attenuated inversion recovery magnetic resonance imaging. The Montreal Cognitive Assessment was used to measure cognitive functioning. Associations between cardiac and brain measures were determined using multivariable linear regression after adjusting for cardiovascular risk factors, education level, and physical activity. ResultsLV ejection fraction was associated with total Montreal Cognitive Assessment score (β = 0.06 [95% CI: 0.003-0.12], P = 0.042) and LV Ecc was associated with WMH volume (β = 0.08 [95% CI: 0.01-0.14], P = 0.025) in the overall cohort without significant interaction by race/ethnicity. Higher LV mass and concentricity were associated with larger WMH volume in the overall cohort (β = 0.13 [95% CI: 0.03-0.23], P = 0.008 and 0.10 [95% CI: 0.03-0.17], P = 0.005). These associations were more predominant in Black than White participants (β = 0.17 [95% CI: 0.04-0.30] vs β = −0.009 [95% CI: −0.16 to 0.14], P = 0.036 and β = 0.22 [95% CI: 0.13-0.32] vs β = −0.11 [95% CI: −0.21 to −0.01], P < 0.0001, for LV mass and concentricity, respectively). ConclusionsSubclinical cardiac dysfunction indicated by LVEF was associated with lower cognitive function. Moreover, LV mass and concentric remodeling were associated with higher WMH burden, particularly among Black individuals.

Spatial patterns of white matter hyperintensities: a systematic review.

White matter hyperintensities are an important marker of cerebral small vessel disease. This disease burden is commonly described as hyperintense areas in the cerebral white matter, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging data. Studies have demonstrated associations with various cognitive impairments, neurological diseases, and neuropathologies, as well as clinical and risk factors, such as age, sex, and hypertension. Due to their heterogeneous appearance in location and size, studies have started to investigate spatial distributions and patterns, beyond summarizing this cerebrovascular disease burden in a single metric-its volume. Here, we review the evidence of association of white matter hyperintensity spatial patterns with its risk factors and clinical diagnoses. We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We used the standards for reporting vascular changes on neuroimaging criteria to construct a search string for literature search on PubMed. Studies written in English from the earliest records available until January 31st, 2023, were eligible for inclusion if they reported on spatial patterns of white matter hyperintensities of presumed vascular origin. A total of 380 studies were identified by the initial literature search, of which 41 studies satisfied the inclusion criteria. These studies included cohorts based on mild cognitive impairment (15/41), Alzheimer's disease (14/41), Dementia (5/41), Parkinson's disease (3/41), and subjective cognitive decline (2/41). Additionally, 6 of 41 studies investigated cognitively normal, older cohorts, two of which were population-based, or other clinical findings such as acute ischemic stroke or reduced cardiac output. Cohorts ranged from 32 to 882 patients/participants [median cohort size 191.5 and 51.6% female (range: 17.9-81.3%)]. The studies included in this review have identified spatial heterogeneity of WMHs with various impairments, diseases, and pathologies as well as with sex and (cerebro)vascular risk factors. The results show that studying white matter hyperintensities on a more granular level might give a deeper understanding of the underlying neuropathology and their effects. This motivates further studies examining the spatial patterns of white matter hyperintensities.

A Fully Automated Visual Grading System for White Matter Hyperintensities of T2-Fluid Attenuated Inversion Recovery Magnetic Resonance Imaging.

The Fazekas scale is one of the most commonly used visual grading systems for white matter hyperintensity (WMH) for brain disorders like dementia from T2-fluid attenuated inversion recovery magnetic resonance (MR) images (T2-FLAIRs). However, the visual grading of the Fazekas scale suffers from low-intra and inter-rater reliability and high labor-intensive work. Therefore, we developed a fully automated visual grading system using quantifiable measurements. Our approach involves four stages: (1) the deep learning-based segmentation of ventricles and WMH lesions, (2) the categorization into periventricular white matter hyperintensity (PWMH) and deep white matter hyperintensity (DWMH), (3) the WMH diameter measurement, and (4) automated scoring, following the quantifiable method modified for Fazekas grading. We compared the performances of our method and that of the modified Fazekas scale graded by three neuroradiologists for 404 subjects with T2-FLAIR utilized from a clinical site in Korea. The Krippendorff's alpha across our method and raters (A) versus those only between the radiologists (R) were comparable, showing substantial (0.694 vs. 0.732; 0.658 vs. 0.671) and moderate (0.579 vs. 0.586) level of agreements for the modified Fazekas, the DWMH, and the PWMH scales, respectively. Also, the average of areas under the receiver operating characteristic curve between the radiologists (0.80 ± 0.09) and the radiologists against our approach (0.80 ± 0.03) was comparable. Our fully automated visual grading system for WMH demonstrated comparable performance to the radiologists, which we believe has the potential to assist the radiologist in clinical findings with unbiased and consistent scoring.

Supratentorial Meningioma Consistency Prediction Utilizing Tumor to Cerebellar Peduncle Intensity on T1 and T2-Weighted and Fluid Attenuated Inversion Recovery Magnetic Resonance Imaging Sequences

Predicting meningioma consistency with preoperative imaging is critical for surgery planning. Preoperative T1 and T2-weighted and fluid attenuated inversion recovery magnetic resonance imaging (MRI) findings of supratentorial meningioma tumors were studied and compared with intraoperative supratentorial meningioma tumor consistency based on the Cavitron ultrasound surgical aspirator (CUSA) and ZADA grading scales in this cohort to predict the tumor consistency before surgery. MRI from 78 consecutive patients who underwent supratentorial meningioma tumor resection between 2018 and 2021 were evaluated preoperatively. An intraoperative tumor consistency grade was applied to these lesions prospectively by the operating surgeon based on CUSA and ZADA grading scales. Tumor/cerebellar peduncle T2-weighted intensity, tumor/cerebellar peduncle T1-weighted intensity (TCT1I), and tumor/cerebellar peduncle fluid attenuated inversion recovery intensity (TCFI) ratios were calculated. Tumor consistency grades and MRI intensity ratios were correlated using one-way ANOVA. Of the 78 patients, 52 (66.7%) were female and 26 (33.3%) were male. Tumor volume correlated with tumor consistency grades on both CUSA (P= 0.005) and ZADA (P= 0.024) grading scales. Also patients age correlated with tumor consistency according to ZADA grading scale (P= 0.024). TCT1I (P= 0.009) and TCFI (P < 0.005) ratios correlated significantly with tumor consistency grade according to CUSA. Similarly, TCT1I (P= 0.0032) and TCFI (P= 0.001) ratios was significantly associated with tumor consistency according to ZADA grading scales. Our findings suggest that higher tumor/cerebellar peduncle T2-weighted intensity and TCFI ratios correlate with softer tumors, while higher TCT1I ratios reveal firmer tumors. These data can assist the surgeon predict the supratentorial meningioma consistency before surgery.

Correlation between Clinical Pain in Temporomandibular Disorders and Signal Intensity of the Retrodiscal Tissue Using Fluid Attenuation Inversion Recovery MRI – A Cross Sectional Study

Temporomandibular disorders (TMD) is a broad term referring to pain and dysfunction of temporomandibular joint (TMJ), nmasticatory muscles and its associated structures. TMD is the most common orofacial pain condition with prominent feature like regional pain in the face and preauricular area during static and dynamic movements. Methods of assessing clinical pain were subjective and not affirmative. There still remains element of drafting the clinical pain evaluation in TMD patients. This study correlated the pain range in TMD patients with the levels of signal intensity (SI) in FLAIR MRI (Fluid Attenuation Inversion Recovery magnetic resonance imaging) to devise an objective pain assessing system based on the SI values. Settings and design: The present study is institution based, observational cross sectional study. A 32 temporomandibular joints were evaluated in the study. Before imaging, subjective pain score were recorded using Visual Analog Scale (VAS). In FLAIR MRI, both grey matter and retro discal tissue were included in the Region of Interest and the SIRs were calculated. SIRs in painful temporomandibular joints were correlated with Visual Analog Scale score. Unpaired t test was used to compare the mean values recorded for SIR. P-value &lt;0.05 is considered to be statistically significant. Study results shows that SIRs of retrodiscal tissue were significantly increased in patient with higher VAS score (p&lt;0.05). Retrodiscal tissue in painful proteinous elements. Keywords: Temporomandibular disorders, Signal intensity, FLAIR MRI, Retrodiscal tissue

Predictive Factors of Favorable Visual Outcomes After Surgery of Tuberculum Sellae Meningiomas: A Multicenter Retrospective Cohort Study

Because of their proximity to the visual structures, tuberculum sellae meningiomas are frequently revealed by ophthalmologic impairment. The goal of surgery is gross total resection and improvement of visual function. The purpose of the present study was to identify the predictors of favorable visual outcomes after surgery of tuberculum sellae meningioma. We retrospectively collected tuberculum sellae meningiomas treated at 2 neurosurgical centers from 2010 to 2020. We collected the clinical, imaging and surgical data and analyzed their effects on the visual outcome. A favorable visual outcome was defined as an increase in visual acuity of ≥0.2 point and/or an increase of >25% of the visual field or complete recovery. A total of 50 patients were included. At 4 months after surgery, 30 patients (60%) had experienced visual improvement. The predictors of a favorable visual outcome were a symptom duration of <6 months, preoperative visual acuity >0.5, a smaller tumor size, and tumor with T2-weighted/fluid attenuated inversion recovery hypersignal on magnetic resonance imaging. During surgery, a soft tumor and a clear brain-tumor interface were associated with favorable visual outcomes. Preoperative optic coherence tomography measurements of the retinal nerve fiber layer thickness >80 μM and ganglion cell complex thickness >70 μM were also associated with a better ophthalmologic outcome. In tuberculum sellae meningiomas, rapid surgical treatment must be performed to optimize vision improvement. A hyperintense lesion on T2-weighted/fluid attenuated inversion recovery magnetic resonance imaging and minor vision impairment at the initial ophthalmologic presentation might give hope for a favorable outcome. Performing optic coherence tomography measurements before surgery could clarify patients' expectations regarding their recovery.

Non-invasive MR imaging of human brain lymphatic networks with connections to cervical lymph nodes

Meningeal lymphatic vessels have been described in animal studies, but limited comparable data is available in human studies. Here we show dural lymphatic structures along the dural venous sinuses in dorsal regions and along cranial nerves in the ventral regions in the human brain. 3D T2-Fluid Attenuated Inversion Recovery magnetic resonance imaging relies on internal signals of protein rich lymphatic fluid rather than contrast media and is used in the present study to visualize the major human dural lymphatic structures. Moreover we detect direct connections between lymphatic fluid channels along the cranial nerves and vascular structures and the cervical lymph nodes. We also identify age-related cervical lymph node atrophy and thickening of lymphatics channels in both dorsal and ventral regions, findings which reflect the reduced lymphatic output of the aged brain.

Segmenting White Matter Hyperintensities on Isotropic Three-Dimensional Fluid Attenuated Inversion Recovery Magnetic Resonance Images: A Comparison of Deep Learning Tools on a Norwegian National Imaging Database

Segmenting White Matter Hyperintensities on Isotropic Three-Dimensional Fluid Attenuated Inversion Recovery Magnetic Resonance Images: A Comparison of Deep Learning Tools on a Norwegian National Imaging Database

Peak ependymal cell stretch overlaps with the onset locations of periventricular white matter lesions

Deep and periventricular white matter hyperintensities (dWMH/pvWMH) are bright appearing white matter tissue lesions in T2-weighted fluid attenuated inversion recovery magnetic resonance images and are frequent observations in the aging human brain. While early stages of these white matter lesions are only weakly associated with cognitive impairment, their progressive growth is a strong indicator for long-term functional decline. DWMHs are typically associated with vascular degeneration in diffuse white matter locations; for pvWMHs, however, no unifying theory exists to explain their consistent onset around the horns of the lateral ventricles. We use patient imaging data to create anatomically accurate finite element models of the lateral ventricles, white and gray matter, and cerebrospinal fluid, as well as to reconstruct their WMH volumes. We simulated the mechanical loading of the ependymal cells forming the primary brain-fluid interface, the ventricular wall, and its surrounding tissues at peak ventricular pressure during the hemodynamic cycle. We observe that both the maximum principal tissue strain and the largest ependymal cell stretch consistently localize in the anterior and posterior horns. Our simulations show that ependymal cells experience a loading state that causes the ventricular wall to be stretched thin. Moreover, we show that maximum wall loading coincides with the pvWMH locations observed in our patient scans. These results warrant further analysis of white matter pathology in the periventricular zone that includes a mechanics-driven deterioration model for the ventricular wall.

Automatic quantification of white matter hyperintensities on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging

White matter hyperintensities (WMH) are areas of increased signal visualized on T2-weighted fluid attenuated inversion recovery (FLAIR) brain magnetic resonance imaging (MRI) sequences. They are typically attributed to small vessel cerebrovascular disease in the context of aging. Among older adults, WMH are associated with risk of cognitive decline and dementia, stroke, and various other health outcomes. There has been increasing interest in incorporating quantitative WMH measurement as outcomes in clinical trials, observational research, and clinical settings. Here, we present a novel, fully automated, unsupervised detection algorithm for WMH segmentation and quantification. The algorithm uses a robust preprocessing pipeline, including brain extraction and a sample-specific mask that incorporates spatial information for automatic false positive reduction, and a half Gaussian mixture model (HGMM). The method was evaluated in 24 participants with varying degrees of WMH (4.9–78.6 cm3) from a community-based study of aging and dementia with dice coefficient, sensitivity, specificity, correlation, and bias relative to the ground truth manual segmentation approach performed by two expert raters. Results were compared with those derived from commonly used available WMH segmentation packages, including SPM lesion probability algorithm (LPA), SPM lesion growing algorithm (LGA), and Brain Intensity AbNormality Classification Algorithm (BIANCA). The HGMM algorithm derived WMH values that had a dice score of 0.87, sensitivity of 0.89, and specificity of 0.99 compared to ground truth. White matter hyperintensity volumes derived with HGMM were strongly correlated with ground truth values (r = 0.97, p = 3.9e-16), with no observable bias (−1.1 [−2.6, 0.44], p-value = 0.16). Our novel algorithm uniquely uses a robust preprocessing pipeline and a half-Gaussian mixture model to segment WMH with high agreement with ground truth for large scale studies of brain aging.

Patients with pretreatment leukoencephalopathy and older patients have more cognitive decline after whole brain radiotherapy

PurposeTo investigate predictors of cognitive decline after whole brain radiotherapy (WBRT) for brain metastases.MethodsA secondary analysis of a phase 2 clinical trial was conducted in patients who received stereotactic radiosurgery for 1–10 brain metastases and WBRT (NCT01046123). The Montreal Cognitive Assessment (MoCA) was performed at baseline and every 3 months after WBRT. Baseline T2-weighted fluid attenuation inversion recovery magnetic resonance imaging was independently assessed by two neuroradiologists for the presence of white matter hyperintensities (WMH) using the Fazekas visual rating scale. WMH were also manually segmented for volumetric analysis. Univariable and multivariable logistic regression were used to test the association between baseline variables and MoCA score decline.ResultsForty-six patients survived ≥ 3 months after treatment. Age (OR 1.12 (1.04–1.21), p < 0.01), baseline WMH volume (OR 1.20, 95% CI 1.06–1.52, p = 0.02) and baseline Fazekas score ≥ 3/6 (OR 6.4, 95% CI 1.7–24.7, p < 0.01) were predictive of MoCA score decline. In multivariable analysis, age was the only significant predictor of MoCA decline. However, all three patients with pre-treatment leukoencephalopathy (Fazekas score = 6/6) had notable adverse outcomes due to cognitive impairment: one required full-time home nursing support and two were institutionalized.ConclusionA greater decline in cognition after WBRT was observed in older patients and patients with a higher baseline WMH burden. Although this study is small and hypothesis-generating, we propose that radiation oncologists should exercise caution in prescribing WBRT if leukoencephalopathy is present on pre-treatment imaging.Trial Registration: clinicaltrials.gov identifier NCT01046123. First posted January 11, 2010. https://clinicaltrials.gov/ct2/show/NCT01046123

Proximal hyper-intense vessel sign on initial FLAIR MRI in hyper-acute middle cerebral artery ischemic stroke: a retrospective observational study.

A hyper-intense vessel sign on fluid attenuated inversion recovery magnetic resonance imaging (FHV) represents slow blood flow in the cerebral arteries. To investigate the relationship between the proximal FHV (pFHV) on initial magnetic resonance imaging (MRI) and the status of the culprit vessel (stenosis, obstruction) in hyper-acute strokes affecting the territory of the middle cerebral artery (MCA). The study participants consisted of 105 patients presenting to the emergency department (ED) with acute MCA infarction within 4.5 h of onset of symptoms. Patients underwent brain MRI within 45 min of arrival at the ED and angiography within 2 h of arrival. Culprit vessel status and presence of a pFHV on initial MRI were investigated retrospectively. The pFHV was observed in 71/105 (67.6%) patients who presented with a hyper-acute MCA infarction. All patients with hyper-acute MCA infarction caused by internal carotid artery (90.6% caused by M1 occlusion, 92.9% caused by M2 occlusion) showed a pFHV on initial MRI. After logistic regression analysis, the presence of a pFHV showed significant positive correlation with large vessel occlusion (adjusted odds ratio [OR] 34.533, 95% confidence interval [CI] 9.781-121.926; P < 0.001). A pFHV was not associated with severe large vessel stenosis. A pFHV is independently representative of the acute occlusion of intervention-eligible proximal arteries within the territory of the MCA. If a patient with a hyper-acute MCA infarction shows a pFHV, aggressive flow augmentation strategies and early activation of intervention team should be warranted for best patient outcome.

Proper fraction of inspired oxygen for reduction of oxygen-induced canine cerebrospinal fluid hyperintensity on fluid attenuation inversion recovery sequence using low-field magnetic resonance imaging.

Oxygen-induced cerebrospinal fluid (CSF) hyperintensity artifact is inevitable in fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) images of anesthetized animals. This experimental study aimed to confirm the occurrence of this artifact on low-field magnetic resonance imaging (MRI), and to determine the fraction of inspired oxygen (FiO2) that is safe and does not induce this artifact in canine brain MRI. Six healthy dogs underwent brain FLAIR MR scans under general anesthesia with 21%, 30%, 50%, 70%, and 100% FiO2. The signal intensity (SI) ratio was calculated as the SI of CSF spaces divided by that of normalizing regions. The SI ratios of 21% FiO2 images were significantly different from those of 100% FiO2 images, indicating the presence of artifacts on 100% FiO2 images. The SI ratios of 30% FiO2 images were not significantly different from those of 21% FiO2 images for any of CSF spaces. However, they were significantly different from those of 100% FiO2 images in the cerebral sulci, third ventricle, interpeduncular cistern, mesencephalic aqueduct, and subarachnoid space at the level of the first cervical vertebra (P<0.05). All dogs had normal partial pressure of arterial oxygen (PaO2) during inhalation of 30% FiO2, while two dogs had low PaO2 during inhalation of 21% FiO2. Our findings support the hypothesis that high FiO2 induces CSF hyperintensity artifact on low-field FLAIR MR images in dogs. FiO2 of 30% is appropriate for obtaining brain FLAIR MR images with fewer artifacts in dogs.

Fully Automatic White Matter Hyperintensity Segmentation using U-net and Skip Connection.

White matter hyperintensity (WMH) is associated with various aging and neurodegenerative diseases. In this paper, we proposed and validated a fully automatic system which integrated classical image processing and deep neural network for segmenting WMH from fluid attenuation inversion recovery (FLAIR) and T1-weighed magnetic resonance (MR) images. A novel skip connection U-net (SC U-net) was proposed and compared with the classical U-net. Experiments were performed on a dataset of 60 images, acquired from three different scanners. Validation analysis and cross-scanner testing were conducted. Compared with U-net, the proposed SC U-net had a faster convergence and higher segmentation accuracy. The software environment and models of the proposed system were made publicly accessible at Dockerhub.

Post-contrast 3D-FLAIR in idiopathic sudden sensorineural hearing loss.

Our study investigated correlations between clinical characteristics, particularly hearing recovery, interval time between onset and three-dimensional fluid attenuation inversion recovery magnetic resonance imaging (3D-FLAIR MRI), and the signal intensity of post-contrast 3D-FLAIR MRI in patients with idiopathic sudden sensorineural hearing loss (SSNHL). The study enrolled 100 SSNHL patients. The signal intensities and asymmetry ratios of the inner ear structures, including the cochleae, vestibules and vestibulocochlear nerve, were evaluated and calculated. The relationships between the clinical characteristics and MRI findings were assessed. After intravenous gadolinium (Gd) injection, 3D-FLAIR revealed high signal intensities in 65 patients. The corrected asymmetry ratios of cochlea correlated closely with interval time between onset and MRI. The asymmetry ratios of the inner ear structures were significantly lower in patients with final complete to partial hearing recovery. The corrected asymmetry ratios of the inner ear structures correlated with initial/final pure tone audiometry (PTA) and hearing recovery in the affected ear. Notably, it was shown that the corrected asymmetry ratios identified a poor prognosis for hearing recovery, with a sensitivity and specificity of 67.9% and 75.0% in the cochlea, 83.3% and 75.0% in the vestibule, and 52.4% and 81.2% in the vestibulocochlear nerve, respectively. Post-contrast 3D-FLAIR after intravenous Gd injection in SSNHL can be used to assess the permeability of the blood-labyrinth and blood-nerve barriers. The asymmetry ratios of the inner ear structures may identify patients with poor prognosis for hearing recovery. Signal characteristics are closely related to interval time between onset and MRI.

Skip Connection U-Net for White Matter Hyperintensities Segmentation From MRI

White matter hyperintensity (WMH) is associated with various aging and neurodegenerative diseases. In this paper, we proposed and validated a fully automatic system which integrates classical image processing and deep neural network for segmenting WHM from fluid attenuation inversion recovery (FLAIR) and T1 magnetic resonance (MR) images. In this system, a novel skip connection U-net (SC U-net) was proposed. In addition, an atlas-based method was introduced in the preprocessing stage to remove non-brain tissues (namely skull-stripping) and thus to improve the segmentation accuracy. Effectiveness of the proposed system was validated on a dataset of 60 paired images based on cross-scanner validation. Our experimental results revealed the effectiveness of the skull-stripping strategy. More importantly, compared to two existing state-of-the-art methods for segmenting WHM, including a U-net-like method and another deep learning method, the proposed SC U-net had a faster convergence, a lower loss and a higher segmentation accuracy. Both quantitative and qualitative analyses (via visual examinations) revealed the superior performance of our proposed SC U-net. The mean dice score of the proposed SC U-net was 78.36% which was much higher than those of a U-net-like method (74.99%) and an alternative deep learning method (74.80%). The software environment and model of the proposed system were made publicly accessible at Dockerhub.

Fully convolutional network ensembles for white matter hyperintensities segmentation in MR images

White matter hyperintensities (WMH) are commonly found in the brains of healthy elderly individuals and have been associated with various neurological and geriatric disorders. In this paper, we present a study using deep fully convolutional network and ensemble models to automatically detect such WMH using fluid attenuation inversion recovery (FLAIR) and T1 magnetic resonance (MR) scans. The algorithm was evaluated and ranked 1st in the WMH Segmentation Challenge at MICCAI 2017. In the evaluation stage, the implementation of the algorithm was submitted to the challenge organizers, who then independently tested it on a hidden set of 110 cases from 5 scanners. Averaged dice score, precision and robust Hausdorff distance obtained on held-out test datasets were 80%, 84% and 6.30 mm respectively. These were the highest achieved in the challenge, suggesting the proposed method is the state-of-the-art. Detailed descriptions and quantitative analysis on key components of the system were provided. Furthermore, a study of cross-scanner evaluation is presented to discuss how the combination of modalities affect the generalization capability of the system. The adaptability of the system to different scanners and protocols is also investigated. A quantitative study is further presented to show the effect of ensemble size and the effectiveness of the ensemble model. Additionally, software and models of our method are made publicly available. The effectiveness and generalization capability of the proposed system show its potential for real-world clinical practice.

Diagnostic accuracy of flair in detection of acute subarachnoid hemorrhage in patients presenting with severe headache

BackgroundFluid attenuation inversion recovery (FLAIR) magnetic resonance imaging (MRI) sequences are previously described for the evaluation of acute subarachnoid hemorrhage (SAH) and demonstrated good sensitivity. This study was designed to find the diagnostic accuracy of FLAIR in detection of acute SAH in patients presenting with severe headache considering the fact that controversy has been observed in previous studies. ObjectiveTo determine diagnostic accuracy of FLAIR in detection of acute subarachnoid hemorrhage in patients presenting with severe headache using lumber puncture as gold standard. MethodologyA total of 245 patients fulfilling selection criteria were enrolled in the study through the emergency department of Combined Military Hospital, Lahore. MRI was performed by Philips Intera Achieva 1.5T super conducting MR unit (Philips Medical Systems, the Netherlands), with the use of a head coil. FLAIR examination was performed at 6700/150 (TR/TE) with an inversion time (TI) of 2200ms, a field of view 230mm, matrix 189×256, scan time of 3min 50s and section thickness 5mm in axial plane. Following MRI, patients underwent lumbar puncture for cerebrospinal fluid (CSF) examination after 8–12h from the onset of event. MRI and CSF analysis results were then compared. ResultsOut of 245 cases, 49.39% (n=121) were between 20–55 years of age while 50.61% (n=124) were between 56–70 years of age, mean±sd was calculated as 52.13±10.45 years, 53.88% (n=132) were male while 46.12% (n=113) were females, frequency of acute subarachnoid hemorrhage in patients presenting with severe headache was recorded as 5.71%(n=14), diagnostic accuracy of FLAIR in detection of acute subarachnoid hemorrhage in patients presenting with severe headache taking lumbar puncture as gold standard as 78.57% sensitivity, 96.53% specificity, 57.89% positive predictive value, 98.67% negative predictive value and accuracy rate was calculated as 95.29%. ConclusionDiagnostic accuracy of FLAIR in detection of acute subarachnoid hemorrhage in patients presenting with severe headache taking lumbar puncture as gold standard is higher and reliable.

Innovation in the imaging perianal fistula: a step towards personalised medicine.

Background:Perianal fistula is a topic both hard to understand and to teach. The key to understanding the treatment options and the likely success is deciphering the exact morphology of the tract(s) and the amount of sphincter involved. Our aim was to explore alternative platforms better to understand complex perianal fistulas through three-dimensional (3D) imaging and reconstruction.Methods:Digital imaging and communications in medicine images of spectral attenuated inversion recovery magnetic resonance imaging (MRI) sequences were imported onto validated open-source segmentation software. A specialist consultant gastrointestinal radiologist performed segmentation of the fistula, internal and external sphincter. Segmented files were exported as stereolithography files. Cura (Ultimaker Cura 3.0.4) was used to prepare the files for printing on an Ultimaker 3 Extended 3D printer. Animations were created in collaboration with Touch Surgery™.Results:Three examples of 3D printed models demonstrating complex perianal fistula were created. The anatomical components are displayed in different colours: red: fistula tract; green: external anal sphincter and levator plate; blue: internal anal sphincter and rectum. One of the models was created to be split in half, to display the internal opening and allow complexity in the intersphincteric space to better evaluated. An animation of MRI fistulography of a trans-sphincteric fistula tract with a cephalad extension in the intersphincteric space was also created.Conclusion:MRI is the reference standard for assessment of perianal fistula, defining anatomy and guiding surgery. However, communication of findings between radiologist and surgeon remains challenging. Feasibility of 3D reconstructions of complex perianal fistula is realized, with the potential to improve surgical planning, communication with patients, and augment training.

Abstract WP38: Lower Fluid Attenuated Inversion Recovery Magnetic Resonance Imaging Signal Intensity After Acute Ischemic Stroke is Associated With Better Discharge Outcomes in Thrombolysed Patients

Background: Increases in FLAIR MRI signal intensity (SI) after acute ischemic stroke (AIS) have been proposed as “tissue clocks”, reflecting the degree of ischemic injury and potential for recovery in brain tissue. We hypothesize that lower SI increases will be a biomarker for less severe tissue injury and hence is potentially salvageable. To test this, we investigated patients who were treated with tPA to determine whether better outcomes were associated with lower FLAIR SI. Methods: Using our Get with the Guidelines database, we retrospectively analyzed AIS patients admitted between 2011 to 2013 who received full-dose tPA based on institutional protocols. Patients were included if they received a CT scan at our hospital before tPA therapy, and MRI performed &lt; 1 h post CT included a usable FLAIR scan and evidence of stroke on acute DWI. SI ratio (SIR) was calculated on the FLAIR by selecting region of interests in hyperintense FLAIR areas that coincided with the acute DWI lesion and matching contralateral regions. Logistic regression analysis was performed using forward stepwise analysis to combine age, sex, admission NIHSS, SIR and onset-to-treatment (OTT) time to predict discharge outcome. Good outcome was defined as discharge to home or in-patient rehabilitation hospital. Results: There were 129 AIS patients who received tPA, and 57 met our imaging criteria. Patient characteristics were: mean±SD age 70±15 years, median [IQR] NIHSS 13 [7-18], OTT 2.1±1.1 h, time-to-MRI 2.1±1.0 h, 58% female and median SIR 1.13 [1.05-1.26]. On a univariate basis, only age (P&lt;0.0001) and NIHSS (P=0.005) were significant predictors of outcome. However, multivariate analysis showed that combining age (P=0.019), NIHSS (P=0.022), and SIR (P=0.018) was able to predict good discharge outcome with 100% [95% CI 63-100%] specificity and 90% [77-96%] sensitivity. Using age and NIHSS alone, resulted in the same specificity but only 71% [56-83%] sensitivity. Discussion: Controlling for age and admission NIHSS, we found that lower FLAIR SIR was a significant predictor of discharge outcome while OTT was not. This suggests that “tissue clocks” may be more accurate than “time clocks” for predicting tissue outcome, and ultimately functional outcome.