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A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images.

Kim S, Lee JW, Chai JW, Yoo HJ, Kang Y, Seo J, Ahn JM, Kang HS - Korean J Radiol (2015)

Bottom Line: The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement.The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, Seongnam 13620, Korea.

ABSTRACT

Objective: The purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS).

Materials and methods: Cervical NFS at bilateral C4/5, C5/6, and C6/7 was classified into the following three grades based on the T2-weighted axial images: Grade 0 = absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root (EFNR); Grade 1 = the narrowest width of the neural foramen the same or less than (but more than 50% of) the width of the EFNR; Grade 2 = the width of the neural foramen the same or less than 50% of the width of the EFNR. The MRIs of 96 patients who were over 60 years old (M:F = 50:46; mean age 68.4 years; range 61-86 years) were independently analyzed by seven radiologists. Interobserver and intraobserver agreements were analyzed using the percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC).

Results: For the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.

Conclusion: The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

No MeSH data available.


Related in: MedlinePlus

Schematic diagrams of grading system for cervical neural foraminal stenosis in axial scans at intervertebral disc level in cervical spine.A, B. Grade 0, normal-absence of neural foraminal stenosis with narrowest width of neural foramen (arrowheads) more than extraforaminal nerve root (black arrows). A shows no narrowing of neural foramen, and B shows mild narrowing. C. Grade 1, non-severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than (but more than 50% of) extraforaminal nerve root width. D. Grade 2, severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than 50% of extraforaminal nerve root width.
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Figure 1: Schematic diagrams of grading system for cervical neural foraminal stenosis in axial scans at intervertebral disc level in cervical spine.A, B. Grade 0, normal-absence of neural foraminal stenosis with narrowest width of neural foramen (arrowheads) more than extraforaminal nerve root (black arrows). A shows no narrowing of neural foramen, and B shows mild narrowing. C. Grade 1, non-severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than (but more than 50% of) extraforaminal nerve root width. D. Grade 2, severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than 50% of extraforaminal nerve root width.

Mentions: Cervical NFS was classified into one of the following three grades by the MR findings on routinely obtained axial T2-weighted images at the cervical disc level (Fig. 1). Grade 0 refers to the absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root at the level of the anterior margin of the superior articular process (Fig. 2). Grade 1 refers to moderate cervical NFS: the narrowest width of the neural foramen is 51-100% of the width of the extraforaminal nerve root at the level of the anterior margin of the superior articular process (Fig. 3). Grade 2 refers to severe cervical NFS, when the width of the neural foramen is the same as or less than 50% of the width of the extraforaminal nerve roots (Fig. 3). The cases that showed nearly complete obliteration of the neural foramen were classified as Grade 2 regardless of the extraforaminal nerve root. In cases of an unclear ipsilateral extraforaminal nerve root on MR axial images, the width of the contralateral extraforaminal nerve root at the level of the superior articular process or the width between the posterior margin of the vertebral artery and the anterior margin of the superior articular process were alternatively used. Because the vertebral arteries are located in the transverse foramen of each cervical vertebra, the posterior margin of the vertebral artery was used as an alternative standard reference for the anterior margin of the extraforaminal nerve root space for the grading system. In addition, the anterior margin of the superior articular process was used as a standard reference for the posterior margin of the extraforaminal nerve root space because of the low prevalence of anatomical variation.


A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images.

Kim S, Lee JW, Chai JW, Yoo HJ, Kang Y, Seo J, Ahn JM, Kang HS - Korean J Radiol (2015)

Schematic diagrams of grading system for cervical neural foraminal stenosis in axial scans at intervertebral disc level in cervical spine.A, B. Grade 0, normal-absence of neural foraminal stenosis with narrowest width of neural foramen (arrowheads) more than extraforaminal nerve root (black arrows). A shows no narrowing of neural foramen, and B shows mild narrowing. C. Grade 1, non-severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than (but more than 50% of) extraforaminal nerve root width. D. Grade 2, severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than 50% of extraforaminal nerve root width.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644751&req=5

Figure 1: Schematic diagrams of grading system for cervical neural foraminal stenosis in axial scans at intervertebral disc level in cervical spine.A, B. Grade 0, normal-absence of neural foraminal stenosis with narrowest width of neural foramen (arrowheads) more than extraforaminal nerve root (black arrows). A shows no narrowing of neural foramen, and B shows mild narrowing. C. Grade 1, non-severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than (but more than 50% of) extraforaminal nerve root width. D. Grade 2, severe cervical neural foraminal stenosis, including narrowest width of neural foramen (arrowheads) same or less than 50% of extraforaminal nerve root width.
Mentions: Cervical NFS was classified into one of the following three grades by the MR findings on routinely obtained axial T2-weighted images at the cervical disc level (Fig. 1). Grade 0 refers to the absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root at the level of the anterior margin of the superior articular process (Fig. 2). Grade 1 refers to moderate cervical NFS: the narrowest width of the neural foramen is 51-100% of the width of the extraforaminal nerve root at the level of the anterior margin of the superior articular process (Fig. 3). Grade 2 refers to severe cervical NFS, when the width of the neural foramen is the same as or less than 50% of the width of the extraforaminal nerve roots (Fig. 3). The cases that showed nearly complete obliteration of the neural foramen were classified as Grade 2 regardless of the extraforaminal nerve root. In cases of an unclear ipsilateral extraforaminal nerve root on MR axial images, the width of the contralateral extraforaminal nerve root at the level of the superior articular process or the width between the posterior margin of the vertebral artery and the anterior margin of the superior articular process were alternatively used. Because the vertebral arteries are located in the transverse foramen of each cervical vertebra, the posterior margin of the vertebral artery was used as an alternative standard reference for the anterior margin of the extraforaminal nerve root space for the grading system. In addition, the anterior margin of the superior articular process was used as a standard reference for the posterior margin of the extraforaminal nerve root space because of the low prevalence of anatomical variation.

Bottom Line: The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement.The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, Seongnam 13620, Korea.

ABSTRACT

Objective: The purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS).

Materials and methods: Cervical NFS at bilateral C4/5, C5/6, and C6/7 was classified into the following three grades based on the T2-weighted axial images: Grade 0 = absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root (EFNR); Grade 1 = the narrowest width of the neural foramen the same or less than (but more than 50% of) the width of the EFNR; Grade 2 = the width of the neural foramen the same or less than 50% of the width of the EFNR. The MRIs of 96 patients who were over 60 years old (M:F = 50:46; mean age 68.4 years; range 61-86 years) were independently analyzed by seven radiologists. Interobserver and intraobserver agreements were analyzed using the percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC).

Results: For the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.

Conclusion: The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

No MeSH data available.


Related in: MedlinePlus