scholarly journals The Feasibility of Haar Feature-Based Endoscopic Ultrasound Probe Tracking for Implanting Hydrogel Spacer in Radiation Therapy for Pancreatic Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Ziwei Feng ◽  
Hamed Hooshangnejad ◽  
Eun Ji Shin ◽  
Amol Narang ◽  
Muyinatu A. Lediju Bell ◽  
...  
Keyword(s):  
Endoscopic Ultrasound ◽  
Feature Vector ◽  
Image Resolution ◽  
Phantom Experiment ◽  
Haar Features ◽  
Haar Feature ◽  
Mri Scans ◽  
Feature Based ◽  
Magnetic Resonance Imaging Mri ◽  
Feature Dictionary

PurposeWe proposed a Haar feature-based method for tracking endoscopic ultrasound (EUS) probe in diagnostic computed tomography (CT) and Magnetic Resonance Imaging (MRI) scans for guiding hydrogel injection without external tracking hardware. This study aimed to assess the feasibility of implementing our method with phantom and patient images.Materials and MethodsOur methods included the pre-simulation section and Haar features extraction steps. Firstly, the simulated EUS set was generated based on anatomic information of interpolated CT/MRI images. Secondly, the efficient Haar features were extracted from simulated EUS images to create a Haar feature dictionary. The relative EUS probe position was estimated by searching the best matched Haar feature vector of the dictionary with Haar feature vector of target EUS images. The utilization of this method was validated using EUS phantom and patient CT/MRI images.ResultsIn the phantom experiment, we showed that our Haar feature-based EUS probe tracking method can find the best matched simulated EUS image from a simulated EUS dictionary which includes 123 simulated images. The errors of all four target points between the real EUS image and the best matched EUS images were within 1 mm. In the patient CT/MRI scans, the best matched simulated EUS image was selected by our method accurately, thereby confirming the probe location. However, when applying our method in MRI images, our method is not always robust due to the low image resolution.ConclusionsOur Haar feature-based method is capable to find the best matched simulated EUS image from the dictionary. We demonstrated the feasibility of our method for tracking EUS probe without external tracking hardware, thereby guiding the hydrogel injection between the head of the pancreas and duodenum.

scholarly journals Regional medical practice variation in high-cost healthcare services

2021 ◽  
Author(s):  
Michael Berger ◽  
Thomas Czypionka
Keyword(s):  
Medical Practice ◽  
Regional Variation ◽  
Multivariate Regression ◽  
Healthcare Services ◽  
Practice Variation ◽  
District Level ◽  
Healthcare Data ◽  
Regional Medical ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri

AbstractMagnetic resonance imaging (MRI) is a popular yet cost-intensive diagnostic measure whose strengths compared to other medical imaging technologies have led to increased application. But the benefits of aggressive testing are doubtful. The comparatively high MRI usage in Austria in combination with substantial regional variation has hence become a concern for its policy makers. We use a set of routine healthcare data on outpatient MRI service consumption of Austrian patients between Q3-2015 and Q2-2016 on the district level to investigate the extent of medical practice variation in a two-step statistical analysis combining multivariate regression models and Blinder–Oaxaca decomposition. District-level MRI exam rates per 1.000 inhabitants range from 52.38 to 128.69. Controlling for a set of regional characteristics in a multivariate regression model, we identify payer autonomy in regulating access to MRI scans as the biggest contributor to regional variation. Nevertheless, the statistical decomposition highlights that more than 70% of the regional variation remains unexplained by differences between the observable district characteristics. In the absence of epidemiological explanations, the substantial regional medical practice variation calls the efficiency of resource deployment into question.

scholarly journals A detailed analysis of anatomical plausibility of crossed and uncrossed streamline rendition of the dentato-rubro-thalamic tract (DRT(T)) in a commercial stereotactic planning system

2021 ◽  
Author(s):  
Volker A. Coenen ◽  
Bastian E. Sajonz ◽  
Peter C. Reinacher ◽  
Christoph P. Kaller ◽  
Horst Urbach ◽  
...  
Keyword(s):  
Surgical Planning ◽  
Ground Truth ◽  
Planning System ◽  
Single Subject ◽  
Fiber Structure ◽  
Native Space ◽  
Volume Of Interest ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
The Individual

Abstract Background An increasing number of neurosurgeons use display of the dentato-rubro-thalamic tract (DRT) based on diffusion weighted imaging (dMRI) as basis for their routine planning of stimulation or lesioning approaches in stereotactic tremor surgery. An evaluation of the anatomical validity of the display of the DRT with respect to modern stereotactic planning systems and across different tracking environments has not been performed. Methods Distinct dMRI and anatomical magnetic resonance imaging (MRI) data of high and low quality from 9 subjects were used. Six subjects had repeated MRI scans and therefore entered the analysis twice. Standardized DICOM structure templates for volume of interest definition were applied in native space for all investigations. For tracking BrainLab Elements (BrainLab, Munich, Germany), two tensor deterministic tracking (FT2), MRtrix IFOD2 (https://www.mrtrix.org), and a global tracking (GT) approach were used to compare the display of the uncrossed (DRTu) and crossed (DRTx) fiber structure after transformation into MNI space. The resulting streamlines were investigated for congruence, reproducibility, anatomical validity, and penetration of anatomical way point structures. Results In general, the DRTu can be depicted with good quality (as judged by waypoints). FT2 (surgical) and GT (neuroscientific) show high congruence. While GT shows partly reproducible results for DRTx, the crossed pathway cannot be reliably reconstructed with the other (iFOD2 and FT2) algorithms. Conclusion Since a direct anatomical comparison is difficult in the individual subjects, we chose a comparison with two research tracking environments as the best possible “ground truth.” FT2 is useful especially because of its manual editing possibilities of cutting erroneous fibers on the single subject level. An uncertainty of 2 mm as mean displacement of DRTu is expectable and should be respected when using this approach for surgical planning. Tractographic renditions of the DRTx on the single subject level seem to be still illusive.

scholarly journals Brain atrophy and clinical characteristics predicting SDMT performance in multiple sclerosis: A 10-year follow-up study

2021 ◽  
Vol 7 (1) ◽  
pp. 205521732199239
Author(s):  
Cecilie Jacobsen ◽  
Robert Zivadinov ◽  
Kjell-Morten Myhr ◽  
Turi O Dalaker ◽  
Ingvild Dalen ◽  
...  
Keyword(s):  
Clinical Data ◽  
Grey Matter Volume ◽  
Lesion Volume ◽  
Information Processing Speed ◽  
Disability Status ◽  
Mri Scans ◽  
Patients At Risk ◽  
Magnetic Resonance Imaging Mri ◽  
Specific Volumes

Objectives To identify Magnetic Resonance Imaging (MRI), clinical and demographic biomarkers predictive of worsening information processing speed (IPS) as measured by Symbol Digit Modalities Test (SDMT). Methods Demographic, clinical data and 1.5 T MRI scans were collected in 76 patients at time of inclusion, and after 5 and 10 years. Global and tissue-specific volumes were calculated at each time point. For the primary outcome of analysis, SDMT was used. Results Worsening SDMT at 5-year follow-up was predicted by baseline age, Expanded Disability Status Scale (EDSS), SDMT, whole brain volume (WBV) and T2 lesion volume (LV), explaining 30.2% of the variance of SDMT. At 10-year follow-up, age, EDSS, grey matter volume (GMV) and T1 LV explained 39.4% of the variance of SDMT change. Conclusion This longitudinal study shows that baseline MRI-markers, demographic and clinical data can help predict worsening IPS. Identification of patients at risk of IPS decline is of importance as follow-up, treatment and rehabilitation can be optimized.

scholarly journals Cross-sectional analysis of follow-up chest MRI and chest CT scans in patients previously affected by COVID-19

2021 ◽  
Author(s):  
Martina Pecoraro ◽  
Stefano Cipollari ◽  
Livia Marchitelli ◽  
Emanuele Messina ◽  
Maurizio Del Monte ◽  
...  
Keyword(s):  
Chest Ct ◽  
Ct Scans ◽  
Imaging Biomarker ◽  
Cross Sectional ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
Sectional Analysis ◽  
Ct And Mri ◽  
Interlobular Septal Thickening

Abstract Purpose The aim of the study was to prospectively evaluate the agreement between chest magnetic resonance imaging (MRI) and computed tomography (CT) and to assess the diagnostic performance of chest MRI relative to that of CT during the follow-up of patients recovered from coronavirus disease 2019. Materials and methods Fifty-two patients underwent both follow-up chest CT and MRI scans, evaluated for ground-glass opacities (GGOs), consolidation, interlobular septal thickening, fibrosis, pleural indentation, vessel enlargement, bronchiolar ectasia, and changes compared to prior CT scans. DWI/ADC was evaluated for signal abnormalities suspicious for inflammation. Agreement between CT and MRI was assessed with Cohen’s k and weighted k. Measures of diagnostic accuracy of MRI were calculated. Results The agreement between CT and MRI was almost perfect for consolidation (k = 1.00) and change from prior CT (k = 0.857); substantial for predominant pattern (k = 0.764) and interlobular septal thickening (k = 0.734); and poor for GGOs (k = 0.339), fibrosis (k = 0.224), pleural indentation (k = 0.231), and vessel enlargement (k = 0.339). Meanwhile, the sensitivity of MRI was high for GGOs (1.00), interlobular septal thickening (1.00), and consolidation (1.00) but poor for fibrotic changes (0.18), pleural indentation (0.23), and vessel enlargement (0.50) and the specificity was overall high. DWI was positive in 46.0% of cases. Conclusions The agreement between MRI and CT was overall good. MRI was very sensitive for GGOs, consolidation and interlobular septal thickening and overall specific for most findings. DWI could be a reputable imaging biomarker of inflammatory activity.

scholarly journals Magnetic resonance imaging (MRI) scans in patients with dorsal root ganglion stimulation

Pain Practice ◽  
2021 ◽  
Author(s):  
Marco Reining ◽  
Dirk Winkler ◽  
Joachim Boettcher ◽  
Juergen Meixensberger ◽  
Michael Kretzschmar
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Resonance Imaging ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri

scholarly journals Electrical stimulation to clinically identify position of the lingual nerve: results of 50 subjects with reliability and correlation with MRI

2021 ◽  
Author(s):  
Sanaa Aljamani ◽  
Callum Youngson ◽  
Fadi Jarad ◽  
Francis O’Neill
Keyword(s):  
Third Molar ◽  
Lingual Nerve ◽  
Observer Agreement ◽  
Electrical Nerve Stimulation ◽  
The Third ◽  
Mri Scans ◽  
Tingling Sensation ◽  
Magnetic Resonance Imaging Mri ◽  
Clinical Determination

Abstract Purpose Recently we described mapping of the lingual nerve clinically in patients using electrical nerve stimulation. This paper reports results of a larger study with inter- and intra-observer reliability and comparison with positional measurements from magnetic resonance imaging (MRI). Methods In 50 healthy participants, measurements were taken when subjects felt a tingling sensation in the tongue induced by a stimulation probe over the lingual nerve. Three positions were measured in relation to the third molar. Measurement reliability was tested for both inter-observer and intra-observer agreement and positional data of the lingual nerve measured clinically was also compared with nerve position as measured from MRI scans. Results Out of 50 participants, 96 nerves (49 = left/47 = right) were included in the study. The lingual nerve was identified in 90% (87) of this sample. The mean of height of the nerve in points A, B and C were 9.64 mm, 10.77 mm and 12.34 respectively. Inter-and intra-observer agreement was considered to be good to excellent (ICC = 0.8–0.96). Agreement between nerve mapping measured values and MRI measured values was good (ICC < 0.6). Conclusion This technique may prove useful for the clinical determination of lingual nerve position prior to procedures in the third molar region.

scholarly journals Multifocal glioblastoma multiform with “encephalitis-like presentation” : a case report

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Issam Sa’adeh ◽  
Mohamed Jamal Saadh
Keyword(s):  
Vasogenic Edema ◽  
Neurological Deficits ◽  
Herpes Simplex Virus 1 ◽  
Glioblastoma Multiform ◽  
Atypical Clinical Presentation ◽  
Mri Scans ◽  
The Central Nervous System ◽  
Magnetic Resonance Imaging Mri ◽  
Simplex Virus ◽  
Multifocal Glioblastoma

Abstract Background Glioblastoma multiform is the most common and aggressive type of primary malignant tumor that affects the central nervous system in adults. It clinically presents with seizures, headache, and/or progressive focal neurological deficits. Radiologically, glioblastoma multiform appears as a single distinguishable, large heterogeneous lesion affecting the cerebrum with characteristic central necrosis, marginal enhancement, and surrounding vasogenic edema. This article describes a patient that exhibited an atypical clinical presentation of multifocal glioblastoma multiform with misleading early radiological features that simulated herpetic encephalitis. Results A 66-year-old female that presented with left-sided hemiparesis and left partial motor seizures underwent multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) scans. A cerebrospinal fluid (CSF) polymerase chain reaction (PCR) test was also performed to screen for herpes simplex virus 1 (HSV-1). Conclusions The early stages of glioblastoma may manifest as symptoms typical to encephalitis, which can delay diagnosis and treatment. Therefore, early diagnosis and identification of atypical glioblastoma multiform presentations, as reported in this article, are essential.

Progress of leukoaraiosis is inhibited by correction of platelet hyper-aggregability

2005 ◽  
Vol 17 (4) ◽  
pp. 689-698 ◽  
Author(s):  
Shigekiyo Fujita ◽  
Tetsuro Kawaguchi ◽  
Toshiyuki Uehara ◽  
Kazuhito Fukushima
Keyword(s):  
Group Versus ◽  
Adenosine Diphosphate ◽  
White Matter Hyperintensity ◽  
Number Of Patients ◽  
Mri Scans ◽  
The Mean ◽  
The Difference ◽  
Magnetic Resonance Imaging Mri ◽  
Observation Period

Background: Platelet hyper-aggregability is an important risk factor for leukoaraiosis. In this study we investigated whether aggravation of leukoaraiosis can be controlled by means of long-term correction of platelet hyper-aggregability.Methods:Twenty-one patients with leukoaraiosis and uncorrected platelet hyper-aggregability were compared with 21 controls matched for age, grade of leukoaraiosis and observation period whose platelet hyper-aggregability was corrected. Platelet aggregability was estimated by an optical analytical method with a nine-stage display using two different concentrations each of adenosine diphosphate (ADP) and collagen (the double ADP method).Results:The mean observation period between two magnetic resonance imaging (MRI) scans for both groups was 4.1 years. In the non-corrected group, moderate to severe aggravation of leukoaraiosis was observed in a large number of patients. In the corrected group, only a small number of patients showed generally mild aggravation of leukoaraiosis. The number of patients showing aggravation of periventricular hyperintensity (PVH) was 7 in 21 in the non-corrected group versus 1 in 21 (p=0.022) in the corrected group, and for aggravation of deep white-matter hyperintensity, these values were 9 in 21 versus 4 in 21, respectively. Thus, the difference was more significant if the degree of aggravation was taken into account.Conclusion:The progress of leukoaraiosis is greatly inhibited by long-term correction of platelet hyper-aggregability.

Robot-Assisted Stereotactic Shunting as a Novel Treatment for Pontine Glioependymal Cysts

2021 ◽  
Author(s):  
Simon Schieferdecker ◽  
Stefan Hunsche ◽  
Faycal El Majdoub ◽  
Mohammad Maarouf
Keyword(s):  
Abducens Nerve ◽  
Ependymal Cells ◽  
Robot Assisted ◽  
Quick Recovery ◽  
Glioependymal Cyst ◽  
Novel Treatment ◽  
First Case ◽  
Mri Scans ◽  
The Central Nervous System ◽  
Magnetic Resonance Imaging Mri

AbstractIn this case report, the authors describe the first case of a glioependymal cyst of the brainstem managed by robot-assisted, stereotactic, cysto-ventricular shunting. Glioependymal cysts are rare congenital cystic lesions that are thought to form by displacement of ependymal cells during the embryonal period. Glioependymal cysts have been reported in a variety of different locations within the central nervous system. However, glioependymal cysts of the brainstem have only been described once before. Here, we report the case of a 53-year-old man who was referred to our department due to hemiparesis, hemihypesthesia, and hemidysesthesia, as well as facial and abducens nerve palsy. A large pontine glioependymal cyst was confirmed via magnetic resonance imaging (MRI) scans. The cyst was subsequently decompressed by connecting the cyst with the fourth ventricle via robot-assisted stereotactic shunt placement. In the postoperative course, the patient made a quick recovery and did not report any permanent neurologic deficits.

scholarly journals The OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging (MRI) Scoring System: Updated Recommendations by the OMERACT MRI in Arthritis Working Group

2017 ◽  
Vol 44 (11) ◽  
pp. 1706-1712 ◽  
Author(s):  
Mikkel Østergaard ◽  
Charles G. Peterfy ◽  
Paul Bird ◽  
Frédérique Gandjbakhch ◽  
Daniel Glinatsi ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Working Group ◽  
Scoring System ◽  
Research Agenda ◽  
Image Resolution ◽  
Sensitivity To Change ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

Objective.The Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis (RA) Magnetic Resonance Imaging (MRI) scoring system (RAMRIS), evaluating bone erosion, bone marrow edema/osteitis, and synovitis, was introduced in 2002, and is now the standard method of objectively quantifying inflammation and damage by MRI in RA trials. The objective of this paper was to identify subsequent advances and based on them, to provide updated recommendations for the RAMRIS.Methods.MRI studies relevant for RAMRIS and technical and scientific advances were analyzed by the OMERACT MRI in Arthritis Working Group, which used these data to provide updated considerations on image acquisition, RAMRIS definitions, and scoring systems for the original and new RA pathologies. Further, a research agenda was outlined.Results.Since 2002, longitudinal studies and clinical trials have documented RAMRIS variables to have face, construct, and criterion validity; high reliability and sensitivity to change; and the ability to discriminate between therapies. This has enabled RAMRIS to demonstrate inhibition of structural damage progression with fewer patients and shorter followup times than has been possible with conventional radiography. Technical improvements, including higher field strengths and improved pulse sequences, allow higher image resolution and contrast-to-noise ratio. These have facilitated development and validation of scoring methods of new pathologies: joint space narrowing and tenosynovitis. These have high reproducibility and moderate sensitivity to change, and can be added to RAMRIS. Combined scores of inflammation or joint damage may increase sensitivity to change and discriminative power. However, this requires further research.Conclusion.Updated 2016 RAMRIS recommendations and a research agenda were developed.

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