Michael Nelles MD, Presenter: Nothing to Disclose

Wolfgang Block PhD, Abstract Co-Author: Nothing to Disclose

Frank Traeber PhD, Abstract Co-Author: Nothing to Disclose

Ullrich Wuellner MD,PhD, Abstract Co-Author: Nothing to Disclose

Hans Heinz Schild MD, Abstract Co-Author: Nothing to Disclose

Horst Urbach MD, Abstract Co-Author: Nothing to Disclose

To assess the diagnostic accuracy of combined 3T 1H-MR-Spectroscopy (MRS) and Diffusion Tensor Imaging (DTI) in patients with suspected motor neuron disease versus EMG, TMS and the El-Escorial scale as a gold standard.

12 patients (9 male, mean age 64 (50 to 81) years) with suspected motor neuron disease were studied with MRS and DTI. For MRS, absolute NAA and relative NAA/Cho ratios of corresponding 40x30x25 mm cubic VOIs within the primary motor cortex were calculated. For DTI, the corticospinal tracts (CST) were tracked using a 3 point seed technique. Fractional anisotropy (FA) values were measured bilaterally at the level of the precentral gyrus, corona radiata, internal capsule, cerebral peduncles, pons and pyramid and compared to a control group of 20 age-matched volunteers. FA statistics were additionally averaged on the CSTs as a whole. Patients were clinically assessed according to the El Escorial and ALSFRS scales.

Clinically, there were 4 "definite”, 2 "probable", and 3 "possible" ALS patients according to the El-Escorial score. Three patients had different diagnoses (Kennedy Syndrome 1, cervical myelopathy 1, polyneuropathy 1). Sensitivity and specificity for detecting upper motor neuron degeneration were 83% and 75% for MRS and 85% and 60% for DTI, repectively. The combination of both methods yielded 85% sensitivity and 80% specificity. MRS and DTI were congruent at the level of the precentral gyrus and corona radiata in all but three cases: one belonged to the “definite” El-Escorial category (DTI indicated first motor neuron degeneration, MRS did not), one was correctly excluded from motor neuron disease by DTI (Kennedy syndrome was proven by genetic analysis) whereas MRS indicated CST involvement. DTI tended to be false-positive for CST affection in a case with lower motor neuron involvement only.

Combined MRS and DTI at 3T effectively adds to classical more invasive procedures to detect and to exclude motor neuron disease.

MRS and DTI at 3T are a means of intensified investigation in the workup of complex pathology and differential diagnoses of lateral sclerosis.

Nelles, M, Block, W, Traeber, F, Wuellner, U, Schild, H, Urbach, H, 3T-Diffusion Tensor Tractography and 1H-MR-Spectroscopy in Motor Neuron Disease.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4437363.html