Hunter's angle

Last revised by Andrew Murphy on 2 Apr 2020

Hunter's angle (HA) is a term coined from a neurosurgeon, C Hunter Shelden, at Huntington Medical Research Institutes. He placed his comb on the spectrum at approximately a 45° angle and connected several of the peaks. If the angle and peaks roughly corresponded to the 45° angle, the curve was considered probably normal. If the peaks strayed off the comb's angle, the curve was abnormal. This is a quick and useful visual method to read MRS and determine normal from abnormal. It is important to remember, however, that this angle was used with STEAM spectra from the brain 2.

Hunter's angle is the line formed by the metabolites in MR spectroscopy.

Metabolites myo-inositol, cholinecreatine, and N-acetyl aspartate (NAA) peaks are ascending in a normal spectrum (Figure 1), any alteration in the ascending nature of the peaks means the spectrum is abnormal.

Hunter's angle is an alternative of doing complex ratios and analysis of the spectra.

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