scholarly journals Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jesse J. Rohr ◽  
Stuart Sater ◽  
Austin M. Sass ◽  
Karina Marshall-Goebel ◽  
Robert J. Ploutz-Snyder ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Magnetic Resonance ◽  
Recovery Period ◽  
Space Station ◽  
Cross Sectional Area ◽  
Quantitative Mri ◽  
Sectional Area ◽  
Cross Sectional ◽  
Before And After ◽  
Increased Icp

Abstract A subset of long-duration spaceflight astronauts have experienced ophthalmic abnormalities, collectively termed spaceflight-associated neuro-ocular syndrome (SANS). Little is understood about the pathophysiology of SANS; however, microgravity-induced alterations in intracranial pressure (ICP) due to headward fluid shifts is the primary hypothesized contributor. In particular, potential changes in optic nerve (ON) tortuosity and ON sheath (ONS) distension may indicate altered cerebrospinal fluid dynamics during weightlessness. The present longitudinal study aims to provide a quantitative analysis of ON and ONS cross-sectional areas, and ON deviation, an indication of tortuosity, before and after spaceflight. Ten astronauts undergoing ~6-month missions on the International Space Station (ISS) underwent high-resolution magnetic resonance imaging (MRI) preflight and at five recovery time points extending to 1 year after return from the ISS. The mean changes in ON deviation, ON cross-sectional area, and ONS cross-sectional area immediately post flight were −0.14 mm (95% CI: −0.36 to 0.08, Bonferroni-adjusted P = 1.00), 0.13 mm2 (95% CI −0.66 to 0.91, Bonferroni-adjusted P = 1.00), and −0.22 mm2 (95% CI: −1.78 to 1.34, Bonferroni-adjusted P = 1.00), respectively, and remained consistent during the recovery period. Terrestrially, ONS distension is associated with increased ICP; therefore, these results suggest that, on average, ICP was not pathologically elevated immediately after spaceflight. However, a subject diagnosed with optic disc edema (Frisen Grade 1, right eye) displayed increased ONS area post flight, although this increase is relatively small compared to clinical populations with increased ICP. Advanced quantitative MRI-based assessment of the ON and ONS could help our understanding of SANS and the role of ICP.

Effect of a neck collar on brain turgor: a potential role in preventing concussions?

2021 ◽  
pp. bjsports-2021-103961
Author(s):  
Michael Dinsmore ◽  
Zakir Hajat ◽  
Connor TA Brenna ◽  
Joseph Fisher ◽  
Lashmi Venkatraghavan
Keyword(s):  
Brain Injury ◽  
Optic Nerve ◽  
Brain Injuries ◽  
Cricoid Cartilage ◽  
Optic Nerve Sheath Diameter ◽  
Cross Sectional Area ◽  
Intracranial Volume ◽  
Sectional Area ◽  
Cross Sectional ◽  
Before And After

BackgroundMild internal jugular vein (IJV) compression, aimed at increasing intracranial fluid volume to prevent motion of the brain relative to the skull, has reduced brain injury markers in athletes suffering repeated traumatic brain injuries. However, an increase in intracranial volume with IJV compression has not been well demonstrated. This study used transorbital ultrasound to identify changes in optic nerve sheath diameter (ONSD) as a direct marker of accompanying changes in intracranial volume.MethodsNineteen young, healthy adult volunteers (13 males and 6 females) underwent IJV compression of 20 cm H2O low in the neck, while in upright posture. IJV cross-sectional area at the level of the cricoid cartilage, and the change in right ONSD 3 mm behind the papillary segment of the optic nerve, were measured by ultrasound. Statistical analysis was performed using a paired t-test with Bonferroni correction.ResultsMean (SD) cross-sectional area for the right IJV before and after IJV compression was 0.10 (0.05) cm2 and 0.57 (0.37) cm2, respectively (p=0.001). ONSD before and after IJV compression was 4.6 (0.5) mm and 4.9 (0.5) mm, respectively (p=0.001).ConclusionsThese data verify increased cerebral volume following IJV compression, supporting the potential for reduced brain ‘slosh’ as a mechanism connecting IJV compression to possibly reducing traumatic brain injury following head trauma.

Cross-sectional area of human trunk paraspinal muscles before and after posterior lumbar surgery using magnetic resonance imaging

2015 ◽  
Vol 25 (3) ◽  
pp. 774-782 ◽  
Author(s):  
Mohammad S. Ghiasi ◽  
Navid Arjmand ◽  
Aboulfazl Shirazi-Adl ◽  
Farzam Farahmand ◽  
Hassan Hashemi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cross Sectional Area ◽  
Lumbar Surgery ◽  
Sectional Area ◽  
Resonance Imaging ◽  
Paraspinal Muscles ◽  
Cross Sectional ◽  
Before And After

Cross-Sectional Area of the Stenotic Lumbar Dural Tube Measured from the Transverse Views of Magnetic Resonance Imaging

1994 ◽  
Vol 7 (5) ◽  
pp. 388???393 ◽  
Author(s):  
Chiaki Hamanishi ◽  
Noboru Matukura ◽  
Masahiko Fujita ◽  
Mituo Tomihara ◽  
Seisuke Tanaka
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Resonance Imaging ◽  
Cross Sectional

Intra- and inter-rater reliability for the measurement of the cross-sectional area of ankle tendons assessed by magnetic resonance imaging

2021 ◽  
pp. 028418512110032
Author(s):  
Henrique Mansur ◽  
Guilherme Estanislau ◽  
Marcos de Noronha ◽  
Rita de Cassia Marqueti ◽  
Emerson Fachin-Martins ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Repeated Measures ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
Rater Reliability ◽  
The Cross ◽  
Very High

Background The cross-sectional area (CSA) records make an essential measurement for determining the mechanical properties of tendons, such as stress and strength. However, there is no consensus regarding the best method to record the CSA from different tendons. Purpose To determine intra- and inter-rater reliability for CSA measures from magnetic resonance imaging (MRI) of the following tendons: tibialis anterior; tibialis posterior; fibularis longus and brevis; and Achilles. Material and Methods We designed an observational study with repeated measures taken from a convenience sample of 20 participants diagnosed with acute or chronic ankle sprain. Two independent raters took three separate records from the CSA of ankle tendon images of each MRI slice. The intra-class correlation coefficient (ICC) and 95% limits of agreement (LoA) defined the quality (associations) and magnitude (differences), respectively, of intra- and inter-rater reliability on the measures plotted by the Bland–Altman method. Results Data showed very high intra- and inter-rater correlations for measures taken from all tendons analyzed (ICC 0.952–0.999). It also revealed an excellent agreement between raters (0.12%–2.3%), with bias no higher than 2 mm2 and LoA in the range of 4.4–7.9 mm2. The differences between repeated measures recorded from the thinnest tendons (fibularis longus and brevis) revealed the lowest bias and narrowest 95% LoA. Conclusion Reliability for the CSA of ankle tendons measured from MRI taken by independent rates was very high, with the smallest differences between raters observed when the thinnest tendon was analyzed.

Quantification of Optic Nerve Cross Sectional Area on MRI: A Novel Protocol using Fiji Software

10.3791/62752 ◽  
2021 ◽  
Author(s):  
Nosaiba Al-Ryalat ◽  
Saif Aldeen AlRyalat ◽  
Lna Malkawi ◽  
Muayad Azzam ◽  
Sana Mohsen
Keyword(s):  
Optic Nerve ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional

scholarly journals INDIRECT DECOMPRESSION BY LATERAL FUSION: ANALYSIS OF SAGITAL ALIGNMENT

2021 ◽  
Vol 20 (1) ◽  
pp. 50-54
Author(s):  
Thyago Guirelle Silva ◽  
Rodrigo Augusto do Amaral ◽  
Raphael Rezende Pratali ◽  
Luiz Pimenta
Keyword(s):  
Magnetic Resonance ◽  
Pelvic Incidence ◽  
Magnetic Resonance Images ◽  
Cross Sectional Area ◽  
Disc Height ◽  
Lower Limbs ◽  
Sectional Area ◽  
Cross Sectional ◽  
Indirect Decompression ◽  
The Mean

ABSTRACT Objective: To verify the effectiveness of indirect decompression after lateral access fusion in patients with high pelvic incidence. Methods: A retrospective, non-comparative, non-randomized analysis of 22 patients with high pelvic incidence who underwent lateral access fusion, 11 of whom were male and 11 female, with a mean age of 63 years (52-74), was conducted. Magnetic resonance exams were performed within one year after surgery. The cross-sectional area of the thecal sac, anterior and posterior disc heights, and bilateral foramen heights, measured pre- and postoperatively in axial and sagittal magnetic resonance images, were analyzed. The sagittal alignment parameters were measured using simple radiographs. The clinical results were evaluated using the ODI and VAS (back and lower limbs) questionnaires. Results: In all cases, the technique was performed successfully without neural complications. The mean cross-sectional area increased from 126.5 mm preoperatively to 174.3 mm postoperatively. The mean anterior disc height increased from 9.4 mm preoperatively to 12.8 mm postoperatively, while the posterior disc height increased from 6.3 mm preoperatively to 8.1 mm postoperatively. The mean height of the right foramen increased from 157.3 mm in the preoperative period to 171.2 mm in the postoperative period and that of the left foramen increased from 139.3 mm in the preoperative to 158.9 mm in the postoperative. Conclusions: This technique is capable of correcting misalignment in spinal deformity, achieving fusion and promoting the decompression of neural elements. Level of evidence III; Retrospective study.

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