A Cross-Sectional Piecewise Constant Model for Segmenting Highly Curved Fiber Tracts in Diffusion MR Images

Abstract Objectives To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions. Methods A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative. Results The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images. Conclusions The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

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Verbal memory deficits associated with fornix atrophy in carbon monoxide poisoning

Journal of the International Neuropsychological Society ◽

10.1017/s1355617701005112 ◽

2001 ◽

Vol 7 (5) ◽

pp. 640-646 ◽

Cited By ~ 36

Author(s):

SHELLI R. KESLER ◽

RAMONA O. HOPKINS ◽

LINDELL K. WEAVER ◽

DUANE D. BLATTER ◽

HOLLY EDGE-BOOTH ◽

...

Keyword(s):

Carbon Monoxide ◽

Verbal Memory ◽

Visual Memory ◽

Carbon Monoxide Poisoning ◽

Neuropsychological Testing ◽

Mr Images ◽

Cross Sectional ◽

Memory Processing ◽

Within Subjects ◽

And Gender

Magnetic resonance (MR) images and neuropsychological testing data of 69 carbon monoxide (CO) poisoned patients were prospectively obtained within 1 day of CO poisoning, two weeks and six months. CO patients' Day 1 cross-sectional fornix surface area measurements, corrected for head size by using a fornix-to-brain ratio (FBR), were compared to normal age and gender-matched controls. Additionally, a within-subjects analysis was performed comparing the mean areas between CO patients' Day 1, 2 weeks and 6-month FBR. The FBR was correlated with patients' neuropsychological data. There were no significant differences between CO patients' Day 1 fornix measurements compared to normal control subjects. However, significant atrophic changes in the fornix of CO poisoned patients occurred at two weeks with no progressive atrophy at 6 months. By 6 months, CO patients showed significant decline on tests of verbal memory (when practice effects were taken into account), whereas visual memory, processing speed and attention/concentration did not decline. This study indicates that CO results in brain damage and cognitive impairments in the absence of lesions and other neuroanatomic markers. (JINS, 2001, 7, 640–646.)

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Musculoskeletal MRI Findings of Haematological Diseases

QJM ◽

10.1093/qjmed/hcab106.057 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

Sameh Mohammed Abdelwahab ◽

Hazem Ibrahim Abdelrahman ◽

Pola Ibrahim Said

Keyword(s):

Bone Marrow ◽

Signal Intensity ◽

Cross Sectional Study ◽

Mr Images ◽

University Hospitals ◽

Mri Findings ◽

Cross Sectional ◽

Hematological Diseases ◽

Musculoskeletal Mri ◽

Normal Composition

Abstract Background Hematologic diseases are a group of prevalent and clinically diverse diseases that can affect any organ system. Hematologic disorders frequently involve bone and associated tissues causing significant alterations in the bone marrow and may have relevant side effects on the skeleton. In order to evaluate findings in bone marrow on MR imaging, it is essential to understand the normal composition and distribution of bone marrow and the changes in marrow that occur with age, as well as the basis for the MR signals from marrow and the factors that affect those signals. Aim of the Work To describe the musculoskeletal MRI findings in patients with hematological diseases. Patients and Methods cross sectional study was conducted in Ain Shams University hospitals on patients confirmed with hematological disease undergoing musculoskeletal MRI. Conclusion Magnetic resonance imaging is very beneficial noninvasive modality to evaluate bone marrow and detecting marrow lesions due to its ability to provide information at the level of cellular and chemical composition. Knowing normal marrow components and composition and their variation, as well as of factors that affect MR signal intensity, is important for optimal interpretation of MR images. The signal intensity, morphology, and location of marrow findings on MRI can be used to provide accurate diagnoses and to guide treatment of the discussed hematological diseases.

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Segmentation of Prostate in Diffusion MR Images via Clustering

Lecture Notes in Computer Science - Image Analysis and Recognition ◽

10.1007/978-3-319-59876-5_52 ◽

2017 ◽

pp. 471-478 ◽

Cited By ~ 1

Author(s):

Junjie Zhang ◽

Sameer Baig ◽

Alexander Wong ◽

Masoom A. Haider ◽

Farzad Khalvati

Keyword(s):

Mr Images ◽

Diffusion Mr

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Effect of unweighting on skeletal muscle use during exercise

Journal of Applied Physiology ◽

10.1152/jappl.1995.79.1.168 ◽

1995 ◽

Vol 79 (1) ◽

pp. 168-175 ◽

Cited By ~ 62

Author(s):

L. L. Ploutz-Snyder ◽

P. A. Tesch ◽

D. J. Crittenden ◽

G. A. Dudley

Keyword(s):

Lower Limb ◽

Weight Bearing ◽

Muscle Group ◽

Mr Images ◽

Cross Sectional ◽

Quadriceps Femoris Muscle ◽

Before And After ◽

Exercise Induced ◽

The Right ◽

Femoris Muscle

Exercise-induced spin-spin relaxation time (T2) shifts in magnetic resonance (MR) images were used to test the hypothesis that more muscle would be used to perform a given submaximal task after 5 wk of unweighting. Before and after unilateral lower limb suspension (ULLS), 7 subjects performed 5 sets of 10 unilateral concentric actions with the quadriceps femoris muscle group (QF) at each of 4 loads: 25, 40, 55, and 70% of maximum. T2-weighted MR images of the thigh were collected at rest and after each relative load. ULLS elicited a 20% decrease in strength of the left unweighted QF and a 14% decrease in average cross-sectional area (CSA) with no changes in the right weight-bearing QF. Average CSA of the left or right QF showing exercise-induced T2 shift increased as a function of exercise intensity both before and after ULLS. On average, 12 +/- 1, 15 +/- 2, 18 +/- 2, and 22 +/- 1 cm2 of either QF showed elevated T2 for the 25, 40, 55, and 70% loads, respectively, before ULLS. Average CSA of the left but not the right QF, showing elevated T2 after ULLS, was increased to 16 +/- 2, 23 +/- 3, 31 +/- 7, and 39 +/- 5 cm2, respectively. The results indicated that unweighting increased exercise-induced T2 shift in MR images, presumably due to greater muscle mass involvement in exercise after than before unweighting, suggesting a change in motor control.

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Imaging and reconstruction of the cytoarchitecture of axonal fibres: enabling biomedical engineering studies involving brain microstructure

10.21203/rs.3.rs-686577/v1 ◽

2021 ◽

Author(s):

Andrea Bernardini ◽

Marco Trovatelli ◽

Michal Klosowski ◽

Matteo Pederzani ◽

Davide Zani ◽

...

Keyword(s):

Focused Ion Beam ◽

Ion Beam ◽

Cell Organelles ◽

Convection Enhanced Delivery ◽

Cross Sectional ◽

Drug Molecules ◽

Fiber Tracts ◽

Brain Microstructure ◽

3D Volume ◽

The Brain

Abstract There is an increased need and focus to understand how local brain microstructure affects the transport of drug molecules directly administered to the brain tissue, for example in convection-enhanced delivery procedures. This study reports the first systematic attempt to characterize the cytoarchitecture of commissural, long association and projection fibers, namely: the corpus callosum, the fornix and the corona radiata. Ovine samples from three different subjects were stained with osmium tetroxide (to enhance contrast from cell organelles and the fibers), embedded in resin and then imaged using scanning electron microscope combined with focused ion beam milling to generate 3D volume reconstructions of the tissue at subcellular spatial resolution. Particular focus has been given to the characteristic cytological feature of the white matter: the axons and their alignment in the tissue. Via 2D images a homogeneous myelination has been estimated via detection of ~40% content of lipids in all the different fiber tracts. Additionally, for each tract, a 3D reconstruction of relatively large volumes (15μm x 15μm x 15μm – including a significant number of axons) has been performed. Namely, outer axonal ellipticity, outer axonal cross-sectional area and their relative perimeter have been measured. The study of well-resolved microstructural features provides useful insight into the fibrous organization of the tissue, whose micromechanical behaviour is that of a composite material presenting elliptical tortuous tubular fibers embedded in the extra-cellular matrix. Drug flow can be captured through microstructurally-based models, leading to a workflow to enable physically-accurate simulations of drug delivery to the targeted tissue.

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