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Magnetic Resonance Imaging (MRI) of the Lumbosacral Plexus with Intravenous Contrast

Published: August 9, 2026Updated: August 16, 2026

An MRI that uses intravenous contrast to examine the lumbosacral spinal nerve plexus in the lower back and pelvis.

Quick summary

["This imaging test helps evaluate the nerves of the lower back and pelvis when symptoms suggest nerve injury, compression, or inflammation."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
105159-8
Short code
MR Lumbosacral plexus W contr IV
Synonyms
MR Lumbosacral plexus W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
44
Ref high
147
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
CPT
84075
SNOMED
27550007
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

Magnetic resonance imaging of the lumbosacral plexus produces detailed pictures of the network of spinal nerves in the lower back and pelvis. Intravenous contrast is given to improve the visibility of tissues, inflammation, and certain abnormalities.

Why might I need this test?

This test may be recommended for pain, numbness, tingling, weakness, or other symptoms that could come from nerve compression, injury, inflammation, or another abnormality affecting the lower spinal nerves.

How is the test performed?

You lie on a table while the MRI scanner creates images using a strong magnetic field and radio waves. A vein is usually used to inject contrast, and the scan may take 30 to 60 minutes. MRI does not use ionizing radiation.

How do I prepare for the test?

Follow the imaging center's instructions, including telling staff about contrast allergies, kidney disease, pregnancy, and any implanted medical devices. You may be asked to remove jewelry and metal objects, and you should be able to remain still during the scan.

Reference range

Adult: 44-147 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lumbosacral plexus MRI with IV contrast

Frequently asked questions

Is this the same as a routine lower-back MRI?
Not necessarily. A lumbosacral plexus MRI focuses on the network of nerves in the lower back and pelvis, and contrast may be used to evaluate inflammation or other abnormalities more clearly.
Does the test involve radiation?
No. MRI uses a magnetic field and radio waves rather than ionizing radiation, although the injected contrast is a medication that can occasionally cause an allergic-like reaction.
How long does the test take?
The scan often takes 30 to 60 minutes, depending on the imaging protocol and whether contrast is needed. Arrival, screening, and recovery time may make the overall visit longer.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy