MRI DISC SPECTROSCOPY vs INVASIVE DISCOGRAPHY FOR IDENTIFYING PAINFUL DISCS

MRI Disc Spectroscopy is an emerging non-invasive MRI technique requiring no invasive injection or contrast dye, which involves spectroscopic analysis of the biochemical composition of intervertebral discs using advanced MRI techniques and specialised software to non-invasively identify pain-generating discs. Studies have demonstrated a high correlation between non invasive MRI Disc Spectroscopy and traditional Invasive Provocative Discography, an often painful procedure first used in 1941 to identify pain-generating discs.

MRI Disc Spectroscopy allows spectral analysis of the biochemical composition of an intervertebral disc to quantify the breakdown of various biomarkers and their ratios, including collagen, proteoglycan, lactate, alanine and relative acidity. Key biomarkers indicating disc degeneration and pain include the breakdown of structural matrix elements such as collagen and proteoglycans, and high levels of pain-generating acids such as Lactate.

MRI Disc Spectroscopy involves performing a baseline MRI scan, performing selective spectroscopic analysis of individual discs to create a spectroscopic chart with biochemical peaks indicating the relative content of specific molecules. The spectroscopic data is then analysed and post-processed to generate a Normalised MRS Score for each disc, from 0 to 1.0, giving an indication of the relative content of pain-generating elements within each disc. Discs higher in Lactate and Propionate (compounds associated with pain generation), typically produce a higher MRS Score (closer to 1), and conversely, discs with lower Lactate and Propionate content typically produce lower scores.

Historically, an invasive procedure know as Invasive Discography (also known as Provocative Discography) has been commonly performed to assess whether an intervertebral discs as a potential pain generator. Invasive discography was first performed in 1941, and involves imaging guided injection of a disc with contrast to determine if discogenic back pain is reproduced at a specific level, and to define intradisc anatomy. The procedure is used to aid localisation of discogenic pain and as an aid to surgical planning. Invasive Discography is often accompanied by significant patient discomfort, despite liberal use of anaesthesia and conscious sedation, and carries the risk of various complications including nerve root injury and infection (discitis).

A 2019 study published in the European Spinal Journal (Gornet et al) compared the results of MRI Disc Spectroscopy with invasive Provocative Discography in 275 lumbar intervertebral discs.

MRI spectroscopy was used to measure the key biomarker composition including acidity ratios to calculate an overall MRS-SCORE, graded 0 to 10, indicating the probability of discogenic pain at that level.

The study demonstrated a high correlation between a high MRI Disc Spectroscopy MRS-SCORE and a positive Provocative Discogram, including 85% accuracy, 82% sensitivity and 88% specificity.

Post operatively, at 6-12 months following surgical management, MRS +ve discs treated surgically had a high correlation with a successful outcome (>90%), and conversely MRS -ve discs treated surgically had a low correlation with a successful outcome (around 50%).

Key Points

• Research suggests that MRI Disc Spectroscopy (MRS) is a safe, painless, non-invasive alternative to traditional Invasive Provocative Discography to identify pain-generating discs, involving no injection or contrast dye.
• MRI Disc Spectroscopy has a high correlation with Invasive Provocative Discography (85% overall) by non-invasively identifying pain-generating discs containing high levels of pain-generating compounds such as Lactate.
• MRI Disc Spectroscopy +ve discs (with a high MRS Score) treated surgically have a high operative success rate (>90%).

Ref : “Magnetic Resonance Spectroscopy (MRS) can identify painful lumbar discs and may facilitate improved clinical outcomes of lumbar surgeries for discogenic pain” ; G. Gornet, J. Peacock, J. Lotz et al; European Spinal Journal; 2019.

Panorama Radiology Specialists offer MRI Discography (MRI Disc Spectroscopy) to aid localisation of discogenic lower back pain.

PRS process MRS data in collaboration with the Siemens research team using specialised syngo.via software. We do not send MRS cases to the USA for data processing, which may be the case in other centres.

PRS accept all MRI Disc Spectroscopy referrals.