Combined 5‐minute double‐echo in steady‐state with separated echoes and 2‐minute proton‐density‐weighted 2D FSE sequence for comprehensive whole‐joint knee MRI assessment

Abstract

Background Clinical knee MRI protocols require upwards of 15 minutes of scan time. Purpose/Hypothesis To compare the imaging appearance of knee abnormalities depicted with a 5‐minute 3D double‐echo in steady‐state (DESS) sequence with separate echo images, with that of a routine clinical knee MRI protocol. A secondary goal was to compare the imaging appearance of knee abnormalities depicted with 5‐minute DESS paired with a 2‐minute coronal proton‐density fat‐saturated (PDFS) sequence. Study Type Prospective. Subjects Thirty‐six consecutive patients (19 male) referred for a routine knee MRI. Field Strength/Sequences DESS and PDFS at 3T. Assessment Five musculoskeletal radiologists evaluated all images for the presence of internal knee derangement using DESS, DESS+PDFS, and the conventional imaging protocol, and their associated diagnostic confidence of the reading. Statistical Tests Differences in positive and negative percent agreement (PPA and NPA, respectively) and 95% confidence intervals (CIs) for DESS and DESS+PDFS compared with the conventional protocol were calculated and tested using exact McNemar tests. The percentage of observations where DESS or DESS+PDFS had equivalent confidence ratings to DESS+Conv were tested with exact symmetry tests. Interreader agreement was calculated using Krippendorff's alpha. Results DESS had a PPA of 90% (88–92% CI) and NPA of 99% (99–99% CI). DESS+PDFS had increased PPA of 99% (95–99% CI) and NPA of 100% (99–100% CI) compared with DESS (both P < 0.001). DESS had equivalent diagnostic confidence to DESS+Conv in 94% of findings, whereas DESS+PDFS had equivalent diagnostic confidence in 99% of findings (both P < 0.001). All readers had moderate concordance for all three protocols (Krippendorff's alpha 47–48%). Data Conclusion Both 1) 5‐minute 3D‐DESS with separated echoes and 2) 5‐minute 3D‐DESS paired with a 2‐minute coronal PDFS sequence depicted knee abnormalities similarly to a routine clinical knee MRI protocol, which may be a promising technique for abbreviated knee MRI. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Utility of deep learning super‐resolution in the context of osteoarthritis MRI biomarkers

“…While the reader study assessed cartilage image quality, an analysis of cartilage lesions may have been useful. However, the DESS sequence used in the OAI has low sensitivity to cartilage lesions, likely due to the combination of the two separate DESS echo contrasts . Future studies separating the two DESS echoes, akin to qDESS, may provide an improved estimate of structural abnormalities.…”

Preoperative MRI of Articular Cartilage in the Knee: A Practical Approach

“…24,25 The quantitative T2 measurements and morphological details depicted through qDESS have been utilized to differentiate between subjects with varying grades of osteoarthritis and in a diagnostic imaging setting. 26,27 Clinically, the morpholog-ical qDESS images can depict regions of degeneration with similar conspicuity as routine clinical MRI, but the addition of T2 maps may depict regions of early chondral degeneration, even prior to morphological changes (►Fig. 20).…”

Rapid Knee MRI Acquisition and Analysis Techniques for Imaging Osteoarthritis

“…Reducing this duration will be essential for pervasive adoption. For qDESS, the primary challenges are unfamiliarity of contrasts and an underestimation of the size of bone marrow edema (BME) 48 . However, this could be addressed with abbreviated protocols where an accelerated 2D FSE sequence can be paired with qDESS to maintain familiarity with image contrasts and to garner the benefits of qDESS 48 …”