scholarly journals Magnetic Resonance Imaging of the Knee in the Presence of Bridging External Fixation: A Comparative Experimental Evaluation of Four External Fixators, Including Dolphix®

2021 ◽  
Vol 7 (1) ◽  
pp. 4
Author(s):  
Francesco Addevico ◽  
Alberto Simoncini ◽  
Giovanni Solitro ◽  
Massimo Max Morandi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Regions Of Interest ◽  
Lower Limbs ◽  
External Fixators ◽  
Resonance Imaging ◽  
Signal To Noise ◽  
Mr Conditional ◽  
Before And After ◽  
The Mean

Performing MR investigation on patients instrumented with external fixators is still controversial. The aim of this study is to evaluate the quality of MR imaging of the knee structures in the presence of bridging external fixators. Different cadaveric lower limbs were instrumented with the MR-conditional external fixators Hofmann III (Stryker, Kalamazoo, MI, USA), Large external Fixator (DePuy Synthes, Raynham, MA, USA), XtraFix (Zymmer, Warsaw, IN, USA) and a newer implant of Ketron Peek CA30 and ERGAL 7075 pins, Dolphix®, (Citieffe, Bologna, Italy). The specimens were MR scanned before and after the instrumentation. The images were subjectively judged by a pool of blinded radiologists and then quantitatively evaluated calculating signal intensity, signal to noise and contrast to noise in the five regions of interest. The area of distortion due to the presence of metallic pins was calculated. All the images were considered equally useful for diagnosis with no differences between devices (p > 0.05). Only few differences in the quantification of images have been detected between groups while the presence of metallic components was the main limit of the procedure. The mean length of the radius of the area of distortion of the pins were 53.17 ± 8.19 mm, 45.07 ± 4.33 mm, 17 ± 5.4 mm and 37.12 ± 10.17 mm per pins provided by Zimmer, Synthes, Citieffe and Stryker, respectively (p = 0.041). The implant of Ketron Peek CA30 and ERGAL 7075 pins showed the smallest distortion area.

scholarly journals “Yokoyama procedure” efficacy on non-highly myopic patients with acquired esotropia and hypotropia

2019 ◽  
Vol 30 (4) ◽  
pp. 676-679
Author(s):  
Massimiliano Serafino ◽  
Matteo Scaramuzzi ◽  
Edoardo Villani ◽  
Paolo Nucci
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Axial Length ◽  
Lateral Rectus ◽  
Inclusion Criteria ◽  
Resonance Imaging ◽  
Spherical Equivalent Refraction ◽  
Before And After ◽  
Weighted Magnetic Resonance Imaging ◽  
The Mean

Objective: To assess the efficacy of “Yokoyama Procedure,” on non-highly myopic patients with acquired esotropia and hypotropia. Methods: The study involved 10 eyes of 5 patients with eso-hypotropia. Inclusion criteria were acquired esotropic-hypotropic strabismus with lateral rectus inferior displacement and superior rectus nasal displacement confirmed by magnetic resonance imaging, refractive errors between ±6 D, and axial length < 27 mm. Range of full duction movements and maximum angles of abduction-sursumduction was measured in each eye before and after surgery. All patients underwent T1- and T2-weighted magnetic resonance imaging. The surgery was aimed at creating a junction between the muscle bellies of the superior and lateral rectus muscles. This junction was made approximately 14 mm behind the insertions using a non-absorbable mersilene 5/0 suture (Yokoyama procedure). Results: Mean patient age was 64.8 ± 4.8 years. The mean globe axial length was 25.4 ± 0.76 mm and a mean corresponding spherical equivalent refraction of −3.7 ± 1.7 D was observed. Eight eyes on 10 had mild limitation in abduction, while the remaining 2 had no limitation. Three out of 10 eyes showed a moderate limited sursumduction, 5 eyes were categorized as mild, and the remaining 2 had no limitation. No evident post-operative limitation was present in any eye, in both abduction and sursumduction (p < 0.01). Pre-operative esotropia and hypotropia were, respectively, 32 ± 11 prismatic diopters and 25 ± 5 prismatic diopters, and they were significantly reduced after surgery as 9 ± 1.7 prismatic diopters and 6 ±1 prismatic diopters (p = 0.043), respectively. Conclusion: Yokoyama procedure is an effective, fast, reversible procedure to face eso-hypotropic acquired strabismus, even in patients with a clear magnetic resonance imaging displacement of superior and lateral rectus muscles, and absence of globe dislocation and of elevated myopia.

scholarly journals Influence of partial k-space filling on the quality of magnetic resonance images

2016 ◽  
Vol 49 (3) ◽  
pp. 158-164
Author(s):  
Tiago da Silva Jornada ◽  
Camila Hitomi Murata ◽  
Regina Bitelli Medeiros
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Magnetic Resonance Images ◽  
Resonance Imaging ◽  
Signal To Noise ◽  
T1 And T2 ◽  
Space Acquisition ◽  
Magnetic Resonance Imaging Equipment

Abstract Objective: To study the influence that the scan percentage tool used in partial k-space acquisition has on the quality of images obtained with magnetic resonance imaging equipment. Materials and Methods: A Philips 1.5 T magnetic resonance imaging scanner was used in order to obtain phantom images for quality control tests and images of the knee of an adult male. Results: There were no significant variations in the uniformity and signal-to-noise ratios with the phantom images. However, analysis of the high-contrast spatial resolution revealed significant degradation when scan percentages of 70% and 85% were used in the acquisition of T1- and T2-weighted images, respectively. There was significant degradation when a scan percentage of 25% was used in T1- and T2-weighted in vivo images (p ≤ 0.01 for both). Conclusion: The use of tools that limit the k-space is not recommended without knowledge of their effect on image quality.

scholarly journals Enhancing magnetic resonance imaging-driven Alzheimer’s disease classification performance using generative adversarial learning

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao Zhou ◽  
Shangran Qiu ◽  
Prajakta S. Joshi ◽  
Chonghua Xue ◽  
Ronald J. Killiany ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Magnetic Resonance ◽  
Image Quality ◽  
Classification Performance ◽  
Resonance Imaging ◽  
Mri Scans ◽  
The Mean

Abstract Background Generative adversarial networks (GAN) can produce images of improved quality but their ability to augment image-based classification is not fully explored. We evaluated if a modified GAN can learn from magnetic resonance imaging (MRI) scans of multiple magnetic field strengths to enhance Alzheimer’s disease (AD) classification performance. Methods T1-weighted brain MRI scans from 151 participants of the Alzheimer’s Disease Neuroimaging Initiative (ADNI), who underwent both 1.5-Tesla (1.5-T) and 3-Tesla imaging at the same time were selected to construct a GAN model. This model was trained along with a three-dimensional fully convolutional network (FCN) using the generated images (3T*) as inputs to predict AD status. Quality of the generated images was evaluated using signal to noise ratio (SNR), Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) and Natural Image Quality Evaluator (NIQE). Cases from the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL, n = 107) and the National Alzheimer’s Coordinating Center (NACC, n = 565) were used for model validation. Results The 3T*-based FCN classifier performed better than the FCN model trained using the 1.5-T scans. Specifically, the mean area under curve increased from 0.907 to 0.932, from 0.934 to 0.940, and from 0.870 to 0.907 on the ADNI test, AIBL, and NACC datasets, respectively. Additionally, we found that the mean quality of the generated (3T*) images was consistently higher than the 1.5-T images, as measured using SNR, BRISQUE, and NIQE on the validation datasets. Conclusion This study demonstrates a proof of principle that GAN frameworks can be constructed to augment AD classification performance and improve image quality.

Magnetic resonance imaging for quantitative flow measurement in infants with hydrocephalus: a prospective study

2008 ◽  
Vol 2 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Paul H. Leliefeld ◽  
Rob H. J. M. Gooskens ◽  
Koen L. Vincken ◽  
Lino M. P. Ramos ◽  
Jeroen van der Grond ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Pressure ◽  
Mr Angiography ◽  
Surgical Intervention ◽  
Clinical Signs ◽  
Resonance Imaging ◽  
Arterial Blood ◽  
Before And After ◽  
Csf Diversion ◽  
The Mean

Object Raised intracranial pressure (ICP) that is associated with hydrocephalus may lead to alterations in cerebral hemodynamics and ischemic changes in the brain. In infants with hydrocephalus, defining the right moment for surgical intervention based on clinical signs alone can sometimes be a difficult task. Clinical signs of raised ICP are known to be unreliable and sometimes even misleading. Furthermore, when sutures are closed, ICP does not always correlate with the size of the ventricles or with the clinical signs or symptoms. In this study the authors investigated whether cerebral blood flow (CBF) can be measured by using quantitative MR angiography in infants with progressive hydrocephalus. In addition, the authors investigated the relationship between CBF and ICP, before and after cerebrospinal fluid (CSF) diversion. Methods Fifteen infants with progressive hydrocephalus (age range 1 day–7 months) were examined. All patients underwent anterior fontanel pressure measurement, MR angiography, and mean arterial blood pressure measurements before and after CSF diversion. Brain volume was measured to compensate for the physiological increase in CBF during brain maturation in infants. Results The mean preoperative ICP was 19.1 ± 8.4 cm H2O (± standard deviation). The mean postoperative ICP was 6.7 ± 4.0 cm H2O (p < 0.005). The mean preoperative CBF was 25.7 ± 11.3 ml/100 cm3 brain/min. After CSF diversion, CBF increased to 50.1 ± 12.1 ml/100 cm3 brain/min (p < 0.005). The mean arterial blood pressure did not change after surgical intervention. Conclusions Magnetic resonance imaging can be used to measure CBF in infants with hydrocephalus. Raised ICP was related to a decrease in CBF. After CSF diversion, CBF and ICP improved to values within the normal range.

O-146 Assessment of focal and diffuse adenomyosis lesions before and after pregnancy on magnetic resonance imaging : a cohort of 139 patients

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
L Legay ◽  
L Marcellin ◽  
P Santulli ◽  
A E Millischer ◽  
C Bordonne ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Time Interval ◽  
Resonance Imaging ◽  
Junctional Zone ◽  
Pelvic Magnetic Resonance Imaging ◽  
Before And After ◽  
The Mean ◽  
The Impact ◽  
Mean Time

Abstract Study question How to assess the different adenomyosis phenotype before and after pregnancy on magnetic resonance imaging according to stringent validated criteria ? Summary answer Diffuse adenomyosis increases significantly after pregnancy while the rate of focal adenomyosis and the mean volume of focal adenomyosis lesions decrease significantly after pregnancy. What is known already Adenomyosis and endometriosis are benign hormone-dependent disorders associated with pelvic pain, dysmenorrhea and/or infertility. The natural course of adenomyosis and endometriosis is still unclear, particularly during pregnancy. Pregnancy is considered to have a positive impact on endometriosis. Several studies regarding the impact of adenomyosis on pregnancy are available. Adenomyosis can cause fertility disorders, miscarriage, preterm birth. However, available data evaluating the effect of pregnancy on adenomyosis are lacking. Study design, size, duration Between January 1st 2010 and September 30th 2020, 139 patients were followed in our referral care center (Gynecology department of Port-Royal Hospital, Paris) for symptomatic adenomyosis and or endometriosis. For each of them, a magnetic resonance imaging were performed before and after pregnancy. The data based on magnetic resonance imaging, pre- and post-pregnancy, were analyzed in a single retrospective study. Participants/materials, setting, methods Patients had to be over 18 years old, to be pregnant and to be followed for symptomatic adenomyosis or endometriosis without any previous surgery. Each pelvic magnetic resonance imaging were performed by a single experienced radiologist. The protocol was identical on a 1.5 T magnetic resonance imaging machine based on validated criteria. The rate of diffuse and focal adenomyosis, the volume of focal adenomyosis lesions and the thickness of maximal junctional zone were reported. Main results and the role of chance The mean age of patients was 34.6 ± 3.4 years old, 83 (59.7%) of patients underwent assisted reproductive technology to be pregnant. The mean time interval between the MRI and the delivery was 55.2 months and the mean time interval between the delivery and the MRI was 32.2 months. Before pregnancy, there was 96 (69.1%) patients with adenomyosis, all phenotype combined versus 111 (79.9%) after pregnancy (p = 0.04) on magnetic resonance imaging. The rate of diffuse adenomyosis increased significantly on magnetic resonance imaging after pregnancy compared to before pregnancy (n = 22 (15.8%) vs n = 41 (29.5%), p = 0.01). The thickness of junctional zone maximal was significantly higher after pregnancy (8.0 mm ± 5.1 vs 12.0 mm ± 4.8, p &lt; 0.01). The rate of focal adenomyosis (n = 55 (39.6) vs n = 34 (24.5), p = 0.01) as well as the volume of focal adenomyosis lesions (6.7 mm3 2.5± vs 6.4 mm3 ± 2.3, p &lt; 0.01) decreased significantly after pregnancy on magnetic resonance imaging. Limitations, reasons for caution This single-center study was conducted in a referral center whom patients presented more severe forms of adenomyosis, which could have affected the external validity of this study. The mean time interval between delivery and MRI was 32.2 month which implies a short follow up period to observe long term outcomes. Wider implications of the findings The hypothesis that a specific hormonal environment during pregnancy may imply a positively impact of the evolution of focal adenomyosis is raised by this study. The evolution of focal adenomyosis after pregnancy is similar to the evolution of endometriosis lesions volume that support shared etiopathogenic mechanisms between the two entities. Trial registration number ‘not applicable’

The Kaplan Fibers of the Iliotibial Band Can Be Identified on Routine Knee Magnetic Resonance Imaging

2019 ◽  
Vol 47 (12) ◽  
pp. 2895-2903 ◽  
Author(s):  
Lachlan Batty ◽  
Jerome Murgier ◽  
Richard O’Sullivan ◽  
Kate E. Webster ◽  
Julian A. Feller ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Sagittal Plane ◽  
Interobserver Reliability ◽  
Joint Line ◽  
Coronal Plane ◽  
Iliotibial Band ◽  
Resonance Imaging ◽  
Lateral Gastrocnemius ◽  
The Mean

Background: The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury. Purpose: To assess if the KF complex can be identified on 3-T MRI using standard knee protocols. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: 3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded. Results: The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1). Conclusion: The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.

Quality of Life for Children with Persistent Sinonasal Symptoms

2003 ◽  
Vol 128 (1) ◽  
pp. 17-26 ◽  
Author(s):  
David J. Kay ◽  
Richard M. Rosenfeld
Keyword(s):  
Quality Of Life ◽  
Clinical Care ◽  
Longitudinal Change ◽  
Good Test ◽  
Routine Clinical Care ◽  
Before And After ◽  
The Mean ◽  
The Individual ◽  
Sinonasal Symptoms

OBJECTIVE: The goal was to validate the SN-5 survey as a measure of longitudinal change in health-related quality of life (HRQoL) for children with persistent sinonasal symptoms. DESIGN AND SETTING: We conducted a before and after study of 85 children aged 2 to 12 years in a metropolitan pediatric otolaryngology practice. Caregivers completed the SN-5 survey at entry and at least 4 weeks later. The survey included 5 symptom-cluster items covering the domains of sinus infection, nasal obstruction, allergy symptoms, emotional distress, and activity limitations. RESULTS: Good test-retest reliability ( R = 0.70) was obtained for the overall SN-5 score and the individual survey items ( R ≥ 0.58). The mean baseline SN-5 score was 3.8 (SD, 1.0) of a maximum of 7.0, with higher scores indicating poorer HRQoL. All SN-5 items had adequate correlation ( R ≥ 0.36) with external constructs. The mean change in SN-5 score after routine clinical care was 0.88 (SD, 1.19) with an effect size of 0.74 indicating good responsiveness to longitudinal change. The change scores correlated appropriately with changes in related external constructs ( R ≥ 0.42). CONCLUSIONS: The SN-5 is a valid, reliable, and responsive measure of HRQoL for children with persistent sinonasal symptoms, suitable for use in outcomes studies and routine clinical care.

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