Purpose To assess volumetric proton MR spectroscopic imaging of the human brain on multi-vendor MRI instruments. Methods Echo-planar spectroscopic imaging (EPSI) was developed on instruments from three manufacturers, with matched specifications and acquisition protocols that accounted for differences in sampling performance, RF power, and data formats. Inter-site reproducibility was evaluated for signal-normalized maps of N-acetylaspartate (NAA), Creatine (Cre) and Choline using phantom and human subject measurements. Comparative analyses included metrics for spectral quality, spatial coverage, and mean values in atlas-registered brain regions. Results Inter-site differences for phantom measurements were under 1.7% for individual metabolites and 0.2% for ratio measurements. Spatial uniformity ranged from 79% to 91%. The human studies found differences of mean values in the temporal lobe, but good agreement in other white-matter regions, with maximum differences relative to their mean of under 3.2%. For NAA/Cre, the maximum difference was 1.8%. In grey-matter a significant difference was observed for frontal lobe NAA. Primary causes of inter-site differences were attributed to shim quality, B0 drift, and accuracy of RF excitation. Correlation coefficients for measurements at each site were over 0.60, indicating good reliability. Conclusion A volumetric intensity-normalized MRSI acquisition can be implemented in a comparable manner across multi-vendor MR instruments.

Differences between KBD cartilage and the normal exhibited a similar pattern among the four pairs examined, indicating the presence of common mechanisms mainly including chondrocyte metabolism and apoptosis that contribute to cartilage destruction in KBD.

The aim of this study was to explore the feasibility and repeatability of amide proton transfer weighted (APTw) MRI for the head and neck on clinical MRI scanners. Six healthy volunteers and four patients with head and neck tumors underwent APTw-MRI scanning at 3T. The APTw signal was quantified by the asymmetric magnetization transfer ratio (MTRasym) at 3.5 ppm. Z-spectra of normal tissues in the head and neck (masseter muscle, parotid glands, submandibular glands and thyroid glands) were analyzed in healthy volunteers. Inter-scan repeatability of APTw-MRI was evaluated in six healthy volunteers. Z-spectra of head and neck tumor patients were produced and APTw signals in these tumors were analyzed. APTw-MRI scanning was successful for all ten subjects. The parotid glands showed the highest APTw signal (~7.6% averagely), while the APTw signals in other tissues were relatively moderate. The repeatability of APTw signals from the masseter muscle, parotid gland, submandibular gland and thyroid gland of healthy volunteers was established. Four head and neck tumors showed positive mean APTw ranging from 1.2% to 3.2%, distinguishable from surrounding normal tissues. APTw-MRI was feasible for the use in the head and neck regions at 3T. The preliminary results on patients with head and neck tumors indicated the potential of APTw-MRI for clinical applications.

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