Four-and-one-half years' experience in monitoring of reproducibility of an MR spectroscopy system--application of in vitro results to interpretation of in vivo data.

[canavan disease]

The primary purpose of this work was to assess long -term in vitro reproducibility of metabolite levels measured using 1 H MRS (proton magnetic resonance spectroscopy ). The secondary purpose was to use the in vitro results for interpretation of 1 H MRS in vivo spectra acquired from patients diagnosed with Canavan disease . 1 H MRS measurements were performed in the period from April 2006 to September 2010 . 118 short and 116 long echo spectra were acquired from a stable phantom during this period . Change-point analysis of the in vitro N-acetylaspartate levels was exploited in the computation of fT factor (ratio of the actual to the reference N-acetylaspartate level normalized by the reciprocity principle ). This coefficient was utilized in the interpretation of in vivo spectra analyzed using absolute reference technique . The monitored time period was divided into six time intervals based on short echo in vitro data (seven time intervals based on long echo in vitro data ) characterized by fT coefficient ranging from 0 .97 to 1 .09 (based on short echo data ) and from 1 .0 to 1 .11 (based on long echo data ). Application of this coefficient to interpretation of in vivo spectra confirmed increased N-acetylaspartate level in Canavan disease . Long -term monitoring of an MRS system reproducibility , allowing for absolute referencing of metabolite levels , facilitates interpretation of metabolic changes in white matter disorders .

Diseases
Validation

Diseases presenting "white matter disorders" symptom

alexander disease

canavan disease

pyruvate dehydrogenase deficiency

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