CEST MRI Method for Lactate Imaging

A CEST MRI method detects lactate in vivo by comparing lactate maps before and after administering a metabolic precursor contrast agent.
Problem:
Lactate levels in tissue can be difficult to image directly with MRI. Conventional MRI does not specifically map lactate exchange effects in tissue. A method is needed to indicate lactate expression with spatial imaging.  method is also needed to compare tissue response before and after contrast administration.
Solution:
The technology applies a lactate-mediated CEST saturation pulse protocol around lactate exchangeable proton frequencies and matching offsets opposite water resonance. It acquires an initial lactate CEST MRI map of a body slice. After administering a metabolic precursor of lactate, it acquires a second lactate CEST MRI map. A contrast image derived from the two maps indicates the level of lactate expression.
Technology:
The method uses saturation pulses at frequency offsets around lactate exchangeable protons and corresponding offsets opposite water resonance. It determines contrast from subtraction images and an image acquired without saturation. The pulse protocol can use variable pulse numbers, shapes, amplitudes, durations, and delays. The protocol can also be adjusted based on the exchange rate of lactate protons.
Advantages:

• Uses MRI to indicate lactate expression in tissue
• Compares pre-administration and post-administration lactate CEST maps
• Uses a contrast image derived from positive and negative saturation offsets
• Allows pulse settings to be adjusted for lactate proton exchange behavior

Applications:

• Tumor imaging: Measures lactate-related changes in tumor tissue using lactate-mediated CEST MRI before and after contrast administration.
• Tissue differentiation: Distinguishes suspected abnormal tissue from normal tissue based on differences in lactate-mediated CEST contrast.
• Treatment monitoring: Monitors the effectiveness of a pharmaceutical agent by comparing lactate-mediated CEST images over time.

Intellectual Property:

• US 10,901,058

Stage of Development:

• Demonstrated in in-vivo animal and human testing.

Desired Partnerships:

• Licensing
• Research collaboration

Reference Media:

• DeBrosse, C., et al.; Sci Rep 2016 Jan 22; 6: 19517

In-Vivo Lactate Chemical Exchange Saturation Transfer (LATEST) a) anatomical image of human calf muscle, (b) two pre-exercise, resting-state CEST maps showing ~1% LATESTasym at 0.5ppm and (c) after 3 minutes of exhaustive exercise, ten post-exercise images acquired over 18 minutes: the first image (c1) obtained 3 minutes after cessation of exercise shows a CEST asymmetry increase in the medial gastrocnemius (MG) and lateral gastrocnemius (LG) muscles of ~4–6%. Each of the subsequent images (c2–10), acquired with a resolution of 1.8 minutes, shows lactate recovery in the MG and LG. All LATEST images acquired using B1rms = 0.73 μT and 3 s duration; Asymmetry plots, corrected for B0 and B1, for pre- and post-exercise LATEST of the (d) medial gastrocnemius (MG) and (e) lateral gastrocnemius muscles from a representative subject, acquired with B1rms = 0.73 μT, 3 s duration.