J Korean Soc Spine Surg.  2013 Mar;20(1):28-33. 10.4184/jkss.2013.20.1.28.

Usefulness of the ProSet MRI for Diagnosis of the Extraforaminal Disc Herniation

• Ahn MW
• Kim US
• Kim GB

• KMID: 2209498
• DOI: http://doi.org/10.4184/jkss.2013.20.1.28

Abstract

STUDY DESIGN: This is a retrospective study.
OBJECTIVES
The purpose of this study is to confirm the clinical usefulness of utilizing ProSet imaging for checking the nerve root compression and swelling in extraforaminal disc herniation. SUMMARY OF LITERATURE REVIEW: Diagnosing extraforaminal disc herniations can be neglected with using a conventional MRI.
MATERIALS AND METHODS
A retrospective analysis was performed on 25 patients, who underwent both conventional & Principles of the selective excitation technique (ProSet) MR imaging for the evaluation of extraforaminal disc herniation, from April 2008 to October 2010. Radiographic analysis was based on the notion that the degree of nerve root compression and swelling was decided by Pfirrmann's classification.
RESULTS
Severe compression in the ProSet 3D rendering image was observed in 21 subjects, as compared with 8 subjects in the conventional axial image. Especially, nothing was ever detected in the conventional sagittal image. Severe compression in the ProSet 3D rendering image was observed in 4 subjects, while their nerve root compression was not clear in the conventional axial image. Severe compression and severe swelling in the ProSet 3D & coronal image was observed in 15 subjects, while their nerve root compression was none or not clear in the conventional sagittal image. The swelling degree of the ProSet coronal image turned out bigger than the swelling degree of conventional axial image, and the signal intensity change was also obvious.
CONCLUSIONS
ProSet imaging is regarded useful to investigate the symptom triggering nerves, because ProSet image not only observes better nerve root compression, but also identifies the swelling degree more easily than that of the conventional magnetic resonance imaging (MRI).

Keyword

Extraforaminal disc herniation; MRI; Principles of the selective excitation technique (ProSet) MRI

MeSH Terms

Humans
Magnetic Resonance Imaging
Radiculopathy
Retrospective Studies

Figure

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  Fig. 1. Schematic diagram of a system for grading lumbar nerve root compromise in coronal plane and axial plane. (A) No compromise of the nerve root. (B) Contact of disc material with the right exiting nerve root. The nerve root is in the normal position and is not dorsally deviated. (C) Dorsal deviation of the right exiting nerve root caused by contact with disc material. (D) Compression of the right exiting nerve root between disc material and the surrounding structure (e.g. pedicle). It may be ap-pear flattened or be indistinguished from disc material.

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  Fig. 2. Comparison of conventional MRI axial view and Proset coronal view, extraforaminal herniation extended to the foramen at L5-S1. (A) Axial T2-weighted image shows left extraforaminal disc herniation with extension to foramen at L5-S1. (B,C) Swelling of the L5 nerve root(arrow) on Proset coronal view and 3D MR radiography is seen.

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  Fig. 3. Comparison of conventional MRI axial view and Proset coronal view of right extraforaminal herniation at L4-5. (A) Axial T2-weighted image shows contact of disc material with the right L4 exiting nerve root. The nerve root is in the normal position and is not dorsally deviated. (Pfirmann stage 1). (B,C) Swelling and compression of the right L4 exiting nerve root (arrow) between disc material and surrounding structure on Proset coronal view and 3D MR radiography is seen (Pfirmann stage 3).

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