Artifacts in musculoskeletal magnetic resonance imaging: identification and correction

Peh, Wilfred C.G.; Chan, J. H. M.

doi:10.1007/s002560100341

Cited by 103 publications

(106 citation statements)

References 42 publications

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“…16 The quality was judged as adequate if main structures in the pelvis (bladder, urethra, vagina) could be identified and differentiated. The quality was judged as inadequate if urethral and pelvic floor structures could not be differentiated.…”

Section: Methodsmentioning

confidence: 99%

The axial location of structural regions in the urethra: a magnetic resonance study in nulliparous women*1

Umek

Kearney

Morgan

et al. 2003

Obstetrics & Gynecology

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OBJECTIVE-To define and quantify the appearance and location of distinct regions of the bladder neck and urethra by using axial magnetic resonance images from healthy, continent, nulliparous women.METHODS-Seventy-eight asymptomatic, healthy, nulliparous women (mean age 29.2 ± 5.4 years) volunteered for this study. All women were proven continent on urodynamic examination. Axial proton density magnetic resonance images of the pelvic floor were analyzed at 5-mm intervals. A geometric origin was established at the internal urethral meatus. The presence or absence of each of six structural regions-the bladder base, bladder neck, striated urethral sphincter, compressor urethrae and urethrovaginal sphincter, perineal membrane, and distal urethra-was then noted in each more distal image. The proportion of women in whom a structural region was seen at each 5-mm interval was recorded.RESULTS-The striated urogenital sphincter was observed at 5-25 mm distal to the bladder base. It was observed 10 and 15 mm below the bladder base in 91% (95% confidence interval [CI] 85%, 98%) and 99% (95% CI 97%, 100%), respectively, of all women. The perineal membrane, marking the distal end of the muscular urethra, was located 20-35 mm distal to the bladder base. The length of the muscular region of the urethra ranged from 20 to 35 mm (mean 24 mm, 95% CI 24, 25 mm).CONCLUSION-Magnetic resonance images allow the normal appearance and location of urethral and bladder neck structures to be quantified in healthy, continent, nulliparous women.To identify the anatomic changes that might be associated with impaired urethral function, it is important first to describe the normal variation in urethral morphology in healthy, continent individuals.Histologic studies have been used to describe this variation in vitro 1-5 ; however, interpretation of the results is complicated by the unknown continence status of the donors. When ultrasound, 6-8 computed tomography, 9 and magnetic resonance 10 are used to study urethral morphology in vivo, along with urodynamic studies of the same individuals, they offer the possibility of correlating structure-function relationships in a way that is not usually possible with in-vitro studies.

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Section: Methodsmentioning

confidence: 99%

The axial location of structural regions in the urethra: a magnetic resonance study in nulliparous women*1

Umek

Kearney

Morgan

et al. 2003

Obstetrics & Gynecology

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“…This suggests that they are caused primarily by local variations (i.e., subvoxelar or between neighboring voxels) in magnetic susceptibility that reflect the heterogeneity of local anatomy and physiology. For example, small blood vessels or sharp transitions in tissue composition (12) cause shifts in resonance frequency that may produce distinguishable components of the water resonance . Spectral resolution higher than that of the present data (ϳ8 Hz) might show more detail than is present in the current images, albeit at the cost of decreased SNR.…”

Section: Discussionmentioning

confidence: 99%

Structure of the water resonance in small voxels in rat brain detected with high spectral and spatial resolution MRI

Fan

MacEneaney

et al. 2002

Magnetic Resonance Imaging

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Purpose: To acquire high spectral and spatial resolution (HiSS) MR images of the water resonance in rat brain, evaluate the lineshape of the water resonance in small voxels, and compare images derived from HiSS data with conventional images. Materials and Methods:Spectroscopic images of rat brain were obtained at 4.7 Tesla using phase encoding gradients only. Spectral resolution in each voxel was ϳ8 Hz and bandwidth was 1000 Hz. Spatial resolution was ϳ250 microns in 1-mm slices. Images were synthesized to show the water signal integral, peak height, linewidth, resonance frequency, and asymmetry.Results: Two or more resolved components of the water resonance were detected in ϳ14% Ϯ 6% of voxels in the brains of eight rats. The water resonances in ϳ20% Ϯ 10% of voxels (n ϭ 8) were highly asymmetric. Images with intensity proportional to water signal peak height, T 2 *, or to selected components of the water resonance showed features that were not evident in conventional images. Conclusions:The complexity of the water signal reflects the anatomy and physiology of the sub-voxelar environment, and may be a useful source of image contrast. HiSS imaging of brain provides accurate anatomic information, and may improve image contrast and delineation of subtle anatomic features.

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“…In some surgically-induced OA animal models, the metal debris remaining in the tissue after surgery can cause significant artefacts and distort the images. For detailed discussion of MR artefacts in musculoskeletal imaging, see Peh et al 2001.…”

Section: Imaging Artefactsmentioning

confidence: 99%

In vivo magnetic resonance imaging of animal models of knee osteoarthritis

Wáng

2008

Lab Anim

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SummaryRecent technical developments in high-field magnetic resonance (MR) scanners, improvement in radio frequency coil design and gradient performance along with the development of efficient pulse sequences and new methods of enhancing contrast have made high-quality imaging of animal arthritis models feasible. MR can provide high-resolution structural information about the osteoarthritic changes in animal models, and also information about the biophysical properties of cartilage. This paper reviews the MR techniques available for animal knee imaging, and the various MR-derived readouts of knee osteoarthritis in animal models. Pitfalls in interpreting animal joint anatomy and joint composition are highlighted.

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Artifacts in musculoskeletal magnetic resonance imaging: identification and correction

Cited by 103 publications

References 42 publications

The axial location of structural regions in the urethra: a magnetic resonance study in nulliparous women*1

The axial location of structural regions in the urethra: a magnetic resonance study in nulliparous women*1

Structure of the water resonance in small voxels in rat brain detected with high spectral and spatial resolution MRI

In vivo magnetic resonance imaging of animal models of knee osteoarthritis

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