Ultrashort echo time adiabatic T (UTE-Adiab-T) is sensitive to human cadaveric knee joint deformation induced by mechanical loading and unloading.

PURPOSE

The development of ultrashort echo time (UTE) MRI sequences has led to improved imaging of tissues with short T relaxation times, such as the deep layer cartilage and meniscus. UTE combined with adiabatic T preparation (UTE-Adiab-T) is an MRI measure with low sensitivity to the magic angle effect. This study aimed to investigate the sensitivity of UTE-Adiab-T to mechanical load-induced deformations in the tibiofemoral cartilage and meniscus of human cadaveric knee joints.

METHODS

Eight knee joints from young (42 ± 12 years at death) donors were evaluated on a 3 T scanner using the UTE-Adiab-T sequence under four sequential loading conditions: load = 0 N (Load0), load = 300 N (Load1), load = 500 N (Load2), and load = 0 N (Unload). UTE-Adiab-T was measured in the meniscus (M), femoral articular cartilage (FAC), tibial articular cartilage (TAC), articular cartilage regions uncovered by meniscus (AC-UC), and articular cartilage regions covered by meniscus (AC-MC) within region of interests (ROIs) manually selected by an experienced MR scientist. The Kruskal-Wallis test, with corrected significance level for multiple comparisons, was used to examine the UTE-Adiab-T differences between different loading conditions.

RESULTS

UTE-Adiab-T decreased in all grouped ROIs under both Load1 and Load2 conditions (-18.7% and - 16.9% for M, -18.8% and - 12.6% for FAC, -21.4% and - 10.7% for TAC, -26.2% and - 13.9% for AC-UC, and - 16.9% and - 10.7% for AC-MC). After unloading, average UTE-Adiab-T increased across all ROIs and within a lower range compared with the average UTE-Adiab-T decreases induced by the two previous loading conditions. The loading-induced differences were statistically non-significant.

CONCLUSIONS

While UTE-Adiab-T reduction by loading is likely an indication of tissue deformation, the increase of UTE-Adiab-T within a lower range by unloading implies partial tissue restoration. This study highlights the UTE-Adiab-T technique as an imaging marker of tissue function for detecting deformation patterns under loading.