Optimization of MRI pulse sequences to visualize the normal pars interarticularis

doi:10.1016/S0009-9260(99)91242-4

Clinical Radiology

Volume 54, Issue 1, January 1999, Pages 63-68

https://doi.org/10.1016/S0009-9260(99)91242-4 Get rights and content

Abstract

Magnetic resonance imaging (MRI) is a potentially useful means of detecting acute pars stress fractures. However, recent publications have highlighted the deficiencies of routine MRI in evaluating the pars interarticularis. Twenty-nine volunteers underwent thin section, multi-planar MR examinations of the lumbar spine to evaluate whether the normal pars could be more reliably demonstrated. MRI examinations were performed with sagittal and reserve angle oblique axial T1W images, and also 3D sagittal gradient echo images with reverse angle reconstructions. Sagittal STIR images were also acquired in 14 cases. Two hundred and ninety pars were evaluated, of which 66% were deemed definitely intact (type I) on the sagittal T1W images alone (continuous marrow throughout the pars). However 93% were deemed intact when all images were reviewed together. The majority of pars defects occur at L4/L5, and 74% of these were intact on the sagittal T1W sequence alone, and 90% on combined sequences. Eighteen pars (6%) were considered to be hypointense (type II) after review of all sequences, but appeared otherwise intact. One volunteer had bilateral definite pars defects (type IV) at L5 on all sequences. This study indicates that improved visualization of the normal pars interarticularis can be achieved with optimized MRI.

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Citation Excerpt :
MRI was more accurate at lower lumbar levels, especially L5, and also L4, and those levels constitute 94% of all fractures. It has been previously reported that greater inter-observer variation occurred in the evaluation of intact pars interarticularis at upper lumbar levels, which reinforces the present findings.14 At the lower lumbar levels, the orientation of the pars interarticularis in the sagittal plane differs from that of the upper lumbar levels.
To compare the diagnostic accuracy of magnetic resonance imaging (MRI) with computed tomography (CT) in stress fractures of the lumbar spine.
Radiological and clinical data from 57 adolescents and young adults with a diagnosis of stress injury of the lumbar spine were retrospectively reviewed. All cases had undergone both 1.5 T MRI and 16-section CT examinations. All MRI and CT images were retrospectively reviewed and evaluated in separate sessions. The fracture morphology (complete/incomplete, localization) and vertebral levels were noted at both the CT and MRI examinations. Bone marrow/peri-osseous soft-tissue oedema was also determined at MRI.
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Original paperOptimization of MRI pulse sequences to visualize the normal pars interarticularis

Abstract

Clinical Radiology

Classification of spondylolysis and spondylolisthesis

Clinical Orthopaedics and Related Research

Painful spondylolysis or spondylolisthesis studied by radiography and single-photon emission computed tomography

Radiology

Stress injuries of the pars interarticularis: radiologic classification and indications for scintigraphy

American Journal of Radiology

Spondylolysis with computed tomography

Radiology

Spondylolysis of the lumbar spine: demonstration of defects and laminal fragmentation

Radiology

Scintigraphy of spinal disorders in adolescents

Skeletal Radiology

Oblique lumbar spine radiographs: importance in young patients

Radiology

Original paper
Optimization of MRI pulse sequences to visualize the normal pars interarticularis