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Skeletal Radiology Jul 2021To investigate the diagnostic accuracy of collagen-sensitive maps derived from dual-energy computed tomography (DECT) for the detection of lumbar disk pathologies in a...
OBJECTIVES
To investigate the diagnostic accuracy of collagen-sensitive maps derived from dual-energy computed tomography (DECT) for the detection of lumbar disk pathologies in a feasibility setting.
MATERIALS AND METHODS
We retrospectively reviewed magnetic resonance imaging (MRI), computed tomography (CT), and DECT datasets acquired in patients who underwent periradicular therapy of the lumbar spine from June to December 2019. Three readers scored DECT collagen maps, conventional CT, and MRI for presence, type, and extent of disk pathology. Contingency table analyses were performed to determine diagnostic accuracy using MRI as standard of reference. Interrater agreement within and between imaging modalities was evaluated by computing intraclass correlation coefficients (ICCs) and Cohen's kappa. Correlation between sum scores of anteroposterior disk displacement was determined by calculation of a paired t test.
RESULTS
In 21 disks in 13 patients, DECT had a sensitivity of 0.87 (0.60-0.98) and specificity of 1.00 (0.54-1.00) for the detection of disk pathology. Intermodality agreement for anteroposterior disk displacement was excellent for DECT (ICC 0.963 [0.909-0.985]) and superior to CT (ICC 0.876 [0.691-0.95]). For anteroposterior disk displacement, DECT also showed greater within-modality interrater agreement (ICC 0.820 [0.666-0.916]) compared with CT (ICC 0.624 [0.39-0.808]).
CONCLUSION
Our data suggest that collagen-sensitive imaging has an added benefit, allowing more accurate evaluation of the extent of disk displacement with higher interrater reliability. Thus, DECT could provide useful diagnostic information in patients undergoing CT for other indications or with contraindications to MRI.
Topics: Collagen; Humans; Lumbar Vertebrae; Magnetic Resonance Imaging; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity; Tomography, X-Ray Computed
PubMed: 33277674
DOI: 10.1007/s00256-020-03685-5 -
Materials (Basel, Switzerland) Dec 2020This paper presents, for the first time, the mechanical model and theoretical analysis of free vibration of a spinning functionally graded graphene nanoplatelets...
This paper presents, for the first time, the mechanical model and theoretical analysis of free vibration of a spinning functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) porous double-bladed disk system. The nanocomposite rotor is made of porous metal matrix and graphene nanoplatelet (GPL) reinforcement material with different porosity and nanofillers distributions. The effective material properties of the system are graded in a layer-wise manner along the thickness directions of the blade and disk. Considering the gyroscopic effect, the coupled model of the double-bladed disk system is established based on Euler-Bernoulli beam theory for the blade and Kirchhoff's plate theory for the disk. The governing equations of motion are derived by employing the Lagrange's equation and then solved by employing the substructure mode synthesis method and the assumed modes method. A comprehensive parametric analysis is conducted to examine the effects of the distribution pattern, weight fraction, length-to-thickness ratio, and length-to-width ratio of graphene nanoplatelets, porosity distribution pattern, porosity coefficient, spinning speed, blade length, and disk inner radius on the free vibration characteristics of the FG-GPLRC double-bladed disk system.
PubMed: 33316987
DOI: 10.3390/ma13245610 -
Journal of the American Veterinary... Jun 2011To prospectively assess whether multiple-site disk fenestration decreases the incidence of recurrent thoracolumbar intervertebral disk herniation (IVDH), compared with... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To prospectively assess whether multiple-site disk fenestration decreases the incidence of recurrent thoracolumbar intervertebral disk herniation (IVDH), compared with single-site disk fenestration, in small-breed dogs treated for IVDH.
DESIGN
Randomized controlled clinical trial.
ANIMALS
207 client-owned dogs.
PROCEDURES
Dogs undergoing decompressive surgery of the spinal cord because of thoracolumbar IVDH between 2001 and 2004 were randomly assigned to receive single-site disk fenestration at the level of surgical decompression (n = 103) or multiple-site disk fenestration of all disks from T11 through L4 (104). Follow-up consisted of complete reevaluation of patients, telephone surveys, and further surgery if signs indicative of recurrence occurred.
RESULTS
189 dogs were available for long-term follow-up: 95 dogs in the single-site disk fenestration group and 94 in the multiple-site disk fenestration group. Twenty-four dogs developed 28 confirmed episodes of recurrent thoracolumbar IVDH. The rate for first-time recurrence was 12.7% (24/189). First-time recurrence rates for single-and multiple-site disk fenestration groups were 17.89% (17/95) and 7.45% (7/94), respectively. Dogs undergoing single-site disk fenestration were significantly more likely to have recurrent thoracolumbar IVDH than were dogs undergoing multiple-site disk fenestration. Disk mineralization at the time of first surgery was associated with recurrence, and 87.5% (21/24) of recurrences occurred at a disk space adjacent to or 1 disk away from the initial lesion. Regardless of disk fenestration group, 22 of 24 (91.7%) recurrences occurred at a nonfenestrated disk space.
CONCLUSIONS AND CLINICAL RELEVANCE
Multiple-site disk fenestration decreased the rate of recurrent IVDH in small-breed dogs, compared with the use of single-site disk fenestration.
Topics: Animals; Dog Diseases; Dogs; Female; Intervertebral Disc Displacement; Male; Odds Ratio; Orthopedic Procedures; Recurrence; Risk Factors
PubMed: 21671814
DOI: 10.2460/javma.238.12.1593 -
Clinical Ophthalmology (Auckland, N.Z.) 2011Eyes with glaucoma are characterized by optic neuropathy with visual field defects in the areas corresponding to the optic disk damage. The exact cause for the...
BACKGROUND
Eyes with glaucoma are characterized by optic neuropathy with visual field defects in the areas corresponding to the optic disk damage. The exact cause for the glaucomatous optic neuropathy has not been determined. Myopia has been shown to be a risk factor for glaucoma. The purpose of this study was to determine whether a significant correlation existed between the microcirculation of the optic disk and the visual field defects and the retinal nerve fiber layer thickness (RNFLT) in glaucoma patients with myopic optic disks.
METHODS
Sixty eyes of 60 patients with myopic disks were studied; 36 eyes with glaucoma (men:women = 19:17) and 24 eyes with no ocular diseases (men:women = 14:10). The mean deviation (MD) determined by the Humphrey field analyzer, and the peripapillary RNFLT determined by the Stratus-OCT were compared between the two groups. The ocular circulation was determined by laser speckle flowgraphy (LSFG), and the mean blur rate (MBR) was compared between the two groups. The correlations between the RNFLT and MBR of the corresponding areas of the optic disk and between MD and MBR of the optic disk in the glaucoma group were determined by simple regression analyses.
RESULTS
The average MBR for the entire optic disk was significantly lower in the glaucoma group than that in the control group. The differences of the MBR for the tissue in the superior, inferior, and temporal quadrants of the optic disk between the two groups were significant. The MBR for the entire optic disk was significantly correlated with the MD (r = 0.58, P = 0.0002) and the average RNFLT (r = 0.53, P = 0.0008). The tissue MBR of the optic disk was significantly correlated with the RNFLT in the superior, inferior, and temporal quadrants.
CONCLUSIONS
Our study suggests that there is a causal relationship between the thinner RNFLT that led to the MD and reduction in the microcirculation in the optic nerve head.
PubMed: 22205831
DOI: 10.2147/OPTH.S23204 -
Efficacy and Safety of Condoliase Disc Administration as a New Treatment for Lumbar Disc Herniation.Spine Surgery and Related Research 2022Condoliase is a newly approved drug that improves symptoms associated with lumbar disk herniation (LDH) by intradiscal administration. This study aimed to evaluate the...
INTRODUCTION
Condoliase is a newly approved drug that improves symptoms associated with lumbar disk herniation (LDH) by intradiscal administration. This study aimed to evaluate the mid-term outcomes of condoliase injection, examine the adverse events, including cases that required surgery after condoliase administration, and verify cases in which condoliase could be effective.
METHODS
We enrolled patients with LDH who were treated conservatively for at least six weeks and received condoliase. We assessed the visual analog scale (VAS) score, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, Oswestry Disability Index, disk height, and disk degeneration for up to 6 months, and we examined the complications. Furthermore, a 50% or more improvement in leg pain VAS score was considered effective. Factors related to symptom improvement were investigated by determining whether lower limb pain improved in six months.
RESULTS
In total, 84 patients were recruited (52 men, 32 women; mean age, 44.2 ± 17.1 [16-86 years]). The duration of illness was 6.7 ± 6.8 (1.5-30) months. All patient-based outcomes significantly improved at 4 weeks after the administration compared with pretreatment. The intervertebral disc height decreased significantly at four weeks after condoliase administration compared with that before administration. Progression of intervertebral disc degeneration occurred in 50% of the patients. Eleven patients underwent herniotomy due to poor treatment effects. Moreover, treatment in 77.4% of the patients was considered effective. A logistic regression analysis revealed that L5/S1 disk administration ( = 0.029; odds ratio, 5.94; 95% confidence interval, 1.20-29.45) were significantly associated with clinical effectiveness.
CONCLUSIONS
Condoliase disk administration improved pain and quality of life over time. Condoliase disk administration was more effective in L5/S1 intervertebral administration.
PubMed: 35224244
DOI: 10.22603/ssrr.2021-0035 -
International Journal of Infectious... Jul 2010The widespread resistance in Gram-negative bacteria has necessitated evaluation of the use of older antimicrobials such as polymyxins. In the present study we evaluated...
BACKGROUND
The widespread resistance in Gram-negative bacteria has necessitated evaluation of the use of older antimicrobials such as polymyxins. In the present study we evaluated the different susceptibility testing methods for polymyxins B and E against Gram-negative bacteria using the new Clinical and Laboratory Standards Institute (CLSI) guidelines.
METHODS
The susceptibility of 281 multidrug-resistant (MDR) Gram-negative bacteria (GNB) to polymyxin B was evaluated, comparing broth microdilution (BMD; reference method), agar dilution, E-test, and disk diffusion. Disk diffusion testing of polymyxin B was also performed against 723 MDR GNB.
RESULTS
Twenty-four of 281 (8.5%) isolates were found to be resistant to polymyxin B by the reference BMD method. The rates of very major errors for agar dilution and E-test (for polymyxin B) were 0.7% and 1%, respectively, and those for disk diffusion (for polymyxin B and polymyxin E) were 1% and 0.7%, respectively. For the 257 isolates found sensitive by reference BMD, the rates of major errors by agar dilution and E-test (for polymyxin B) were 2.4% and 0%, respectively, and those for disk diffusion (polymyxin B and polymyxin E) were 0% and 0.7%, respectively. Twenty-six (3.6%) of the 723 Gram-negative isolates were resistant to polymyxin B by disk diffusion.
CONCLUSION
The E-test and agar dilution methods showed good concordance with BMD. The disk diffusion method can be useful for initial screening in diagnostic laboratories.
Topics: Anti-Bacterial Agents; Colistin; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Gram-Negative Bacteria; Humans; Microbial Sensitivity Tests; Polymyxin B
PubMed: 20045367
DOI: 10.1016/j.ijid.2009.09.001 -
American Journal of Ophthalmology Nov 1992We compared the change in cup/disk ratio and neuroretinal rim area-to-disk area to estimated change in the number of optic nerve fibers in 12 cynomolgus monkeys with... (Comparative Study)
Comparative Study
We compared the change in cup/disk ratio and neuroretinal rim area-to-disk area to estimated change in the number of optic nerve fibers in 12 cynomolgus monkeys with unilateral experimental glaucoma. Changes in the cup/disk ratios and neuroretinal rim area-to-disk area were estimated from stereoscopic optic disk photographs that were obtained before and after the development of increased intraocular pressure. Change in the number of optic nerve fibers in the glaucomatous nerves was estimated by comparing them to their fellow normal nerves. A significant linear correlation was present between change in the cup/disk ratios and neuroretinal rim area-to-disk area, and estimated change in the number of optic nerve fibers (r > or = .85; P < .0002). In optic disks with initial cup/disk ratios of 0.2 to 0.3 and neuroretinal rim area-to-disk area of 0.9, an increase in the cup/disk ratio of 0.1 and a decrease of 0.1 in the neuroretinal rim area-to-disk area is associated with a 10% and 9% loss of optic nerve fibers, respectively.
Topics: Animals; Cell Count; Glaucoma; Intraocular Pressure; Macaca fascicularis; Nerve Fibers; Optic Disk
PubMed: 1443015
DOI: 10.1016/s0002-9394(14)74482-4 -
Journal of Clinical Microbiology Jun 2018We evaluated the correlation between MIC and disk diffusion inhibition zones when testing ceftazidime-avibactam, using the 30/20-μg disk and the disk diffusion and MIC...
We evaluated the correlation between MIC and disk diffusion inhibition zones when testing ceftazidime-avibactam, using the 30/20-μg disk and the disk diffusion and MIC breakpoints established by the U.S. FDA and the Clinical and Laboratory Standards Institute (CLSI). Organisms used included 2 groups of isolates and 2 groups of isolates; 1 group of each consisted of randomly selected isolates and the second group consisted of a challenge group from thousands of surveillance isolates with an increased proportion of organisms displaying ceftazidime-avibactam MIC values close to the breakpoints. Broth microdilution, disk diffusion tests, and data analysis were performed according to reference standardized methods. Ceftazidime-avibactam breakpoints of ≤8/4 (susceptible) and ≥16/4 μg/ml (resistant) for MIC and ≥21/≤20 mm for disk diffusion, as established by the U.S. FDA and the CLSI, were applied for and Ceftazidime-avibactam MIC and disk zone (30/20-μg disk) correlation were acceptable when testing (overall, very major [VM] and major [Ma] error rates of 0.4% and 0.0%, respectively) and nearly so when testing (2.3% VM and 2.9% Ma errors). In summary, disk diffusion and broth microdilution testing results demonstrated good categorical agreement for ceftazidime-avibactam against and , using 30/20-μg disks.
Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Ceftazidime; Disk Diffusion Antimicrobial Tests; Drug Combinations; Enterobacteriaceae; Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa; United States; United States Food and Drug Administration
PubMed: 29563198
DOI: 10.1128/JCM.01960-17 -
Journal of Neuro-ophthalmology : the... Mar 2012The fluorescein angiographic criteria for differentiating optic disc drusen (ODD) from optic disc edema have been unclear. We designed a study to identify distinguishing... (Review)
Review
BACKGROUND
The fluorescein angiographic criteria for differentiating optic disc drusen (ODD) from optic disc edema have been unclear. We designed a study to identify distinguishing angiographic features of each and to apply them to cases where both drusen and edema were present.
METHODS
A computer search was performed for cases evaluated in a university academic neuro-ophthalmology consultative practice and coded as ODD; all cases were reviewed, and those with fluorescein angiography were selected for further study. Cases were classified as either buried or surface ODD. Ten cases with papilledema were selected for comparison. Eight cases of coexistent drusen and edema were identified. Autofluorescence, early leakage, early blockage, early and late nodular staining, late peripapillary staining, and late leakage were tabulated.
RESULTS
Two hundred sixteen cases of ODD were identified; 62 (116 eyes) had adequate fluorescein angiography for study. Twenty-three eyes were classified as surface ODD; 90% demonstrated early nodular staining of the disc, with late nodular staining in 90% and late circumferential peripapillary staining in 22%; autofluorescence was visible in 93% with preinjection photography. Eighty-three eyes were classified as buried ODD; 25% demonstrated early nodular staining, with late nodular staining in 29% and late circumferential peripapillary staining in 80%; autofluorescence was visible in 12% of those with preinjection photography. In 9 eyes, buried ODD were present with superimposed true edema. In these eyes, early dye leakage, late nodular hyperfluorescence, and late leakage were present.
CONCLUSION
Early and late fluorescein angiographic features reliably distinguish ODD from edema and may be particularly useful when the conditions coexist.
Topics: Adolescent; Adult; Aged; Child; Diagnosis, Differential; Female; Fluorescein Angiography; Humans; Male; Middle Aged; Optic Disk; Optic Disk Drusen; Papilledema; Retinal Artery; Retrospective Studies; Young Adult
PubMed: 21926917
DOI: 10.1097/WNO.0b013e31823010b8 -
Journal of Infection and Public Health Oct 2020Antibiotic-resistant bacteria are one of the major global health issues that can affect humans, animals, and the environment. Antibiotic-resistant bacteria have emerged...
BACKGROUND
Antibiotic-resistant bacteria are one of the major global health issues that can affect humans, animals, and the environment. Antibiotic-resistant bacteria have emerged as opportunistic pathogenic bacteria that are frequently isolated from both clinical patients and healthy individuals. The aim of this study was to characterize the antibiotic-resistant bacteria isolated from powdered infant formulas marketed in Riyadh, Saudi Arabia.
METHODS
Infant powdered milk formulas were purchased from different pharmacies located within Riyadh, and ten products of powdered milk formulas designed for children of various ages were then transferred to the laboratory in the Department of Botany and Microbiology at King Saud University, Riyadh. Isolation and purification of Bacillus species were both performed according to standard protocols. The identification test was performed using the automated Vitek 2 system (BioMerieux, France), and antibiotic sensitivity tests were performed using the disk-diffusion method incorporating standard antibiotic disks foramikacin (30μg/disk), gentamicin (10μg/disk), imipenem (10μg/disk), moxifloxacin (5μg/disk), cefoperazone (75μg/disk), cefpodoxime (10μg/disk), ceftazidime (30μg/disk), and cefepime (30μg/disk). Statistical analysis was performed using Ward's method to obtain antibiotic resistance of the isolates.
RESULTS
The results obtained from the milk samples indicated that all isolates were sensitive to amikacin, gentamicin, and moxifloxacin. A group of isolates obtained from milk was resistant to cefoperazone by 6.49%, cefpodoxime by 25.9%, ceftazidime by 14.28%, and cefepime by 19.48%.
CONCLUSIONS
Based on these findings, we concluded that the powdered infant formula marketed in Riyadh City may act as a source of bacterial isolates that are resistant to several standard antibiotics.
Topics: Animals; Anti-Bacterial Agents; Bacillus; Child; France; Humans; Infant; Infant Formula; Microbial Sensitivity Tests; Milk; Powders; Public Health; Saudi Arabia
PubMed: 31870631
DOI: 10.1016/j.jiph.2019.11.013