2 research outputs found
Time-efficient combined morphologic and quantitative joint MRI based on clinical image contrasts -- An exploratory in-situ study of standardized cartilage defects
OBJECTIVES: Quantitative MRI techniques such as T2 and T1 mapping are
beneficial in evaluating cartilage and meniscus. We aimed to evaluate the
MIXTURE (Multi-Interleaved X-prepared Turbo-Spin Echo with IntUitive
RElaxometry) sequences that provide morphologic images with clinical turbo
spin-echo (TSE) contrasts and additional parameter maps versus reference TSE
sequences in an in-situ model of human cartilage defects.
MATERIALS AND METHODS: Prospectively, standardized cartilage defects of 8mm,
5mm, and 3mm diameter were created in the lateral femora of 10 human cadaveric
knee specimens (8110 years, nine male/one female). Using a clinical 3T MRI
scanner and knee coil, MIXTURE sequences combining (i) proton-density weighted
fat-saturated (PD-w FS) images and T2 maps and (ii) T1-weighted images and
T1 maps were acquired before and after defect creation, alongside the
corresponding 2D TSE and 3D TSE reference sequences. Defect delineability, bone
texture, and cartilage relaxation times were quantified. Inter-sequence
comparisons were made using appropriate parametric and non-parametric tests.
RESULTS: Overall, defect delineability and texture features were not
significantly different between the MIXTURE and reference sequences. After
defect creation, relaxation times increased significantly in the central femur
(for T2) and all regions combined (for T1).
CONCLUSION: MIXTURE sequences permit time-efficient simultaneous morphologic
and quantitative joint assessment based on clinical image contrasts. While
providing T2 or T1 maps in clinically feasible scan time, morphologic
image features, i.e., cartilage defect delineability and bone texture, were
comparable between MIXTURE and corresponding reference sequences.Comment: 12 pages (main body), 3 tables, 6 figure
Two for One -- Combined Morphologic and Quantitative Knee Joint MRI Using a Versatile Turbo Spin-Echo Platform
Introduction: Quantitative MRI techniques such as T2 and T1\r{ho} mapping are
beneficial in evaluating knee joint pathologies; however, long acquisition
times limit their clinical adoption. MIXTURE (Multi-Interleaved X-prepared
Turbo-Spin Echo with IntUitive RElaxometry) provides a versatile turbo
spin-echo (TSE) sequence platform for simultaneous morphologic and quantitative
joint imaging yet lacks comparative evaluation in basic and translational
research contexts.
Methods: Two MIXTURE sequences were designed along clinical requirements: (i)
MIX1, combining proton density (PD)-weighted fat-saturated (FS) images and
quantitative T2 mapping (acquisition time: 4:59 min), and (ii) MIX2, combining
T1-weighted images with quantitative T1\r{ho} mapping (6:38 min). MIXTURE
sequences and their reference 2D and 3D TSE counterparts were acquired from ten
human cadaveric knee joints using a clinical 3T MRI scanner and knee coil.
Contrast, contrast-to-noise ratios, and coefficients of variation were
comparatively evaluated using parametric tests. Clinical radiologists (n=3)
assessed diagnostic quality as a function of sequence and anatomic structure
using 5-point Likert scales and ordinal regression. The significance level was
set to {\alpha}=0.01.
Results: MIX1 and MIX2 had at least equal diagnostic quality compared to the
2D and 3D TSE sequences of the same image weighting. Contrast,
contrast-to-noise ratios, and coefficients of variation were largely similar
for the PD-weighted FS and T1-weighted images.
Discussion: In clinically feasible scan times, the MIXTURE sequence platform
yields (i) morphologic images of diagnostic quality and adjustable TSE-based
contrasts and (ii) quantitative parameter mapping with additional insights on
soft tissue composition and ultrastructure.Comment: 13 pages (main text), 7 figures, 3 table