Short/Ultra-Short TE MRI Sequences Comparable to CT and Superior to Standard MRI Sequences for Canine Skull Imaging

Magnetic resonance imaging often needs to be complemented with CT for complete assessment of bony structures due to CTs increased spatial resolution and discrimination of cortical bone margins. The aims of this prospective method comparison study were to perform qualitative and quantitative comparisons of standard MR sequences with three short/ultra-short TE MR sequences using CT as the gold standard. Eight healthy research dogs of similar size had CT and MR of the head performed. Three short/ultra-short TE sequences, VIBE, PETRA, and UTE, alongside standard T2W, PD, and T1W TSE sequences of the head were obtained. Slice thickness of CT and short TE MR sequences were matched. A qualitative scale was used to assess the visibility of cortical margins and skull foramina. For the quantitative assessment, predetermined osseous structures and foramina on designated slices were measured. Levene's test and post hoc folded F tests with false discovery rate adjustments were applied to the residuals from these models to compare precision relative to CT across the sequence types. The short/ultra-short TE MR sequences were significantly better than the standard MR sequences for quantitative assessment of bone thickness of smaller structures and overall qualitative assessment. Any of these short/ultra-short TE sequences may be viable to incorporate into a clinical setting as an alternative to CT to help further evaluate the skull and reduce anesthesia time and client cost. VIBE, PETRA, and UTE sequences have diagnostic image quality and provide a consistent quantitative and qualitative assessment of the cortical bone of the skull when compared with CT.