Zero echo time MRI with deep learning reconstruction and chemical shift correction for detecting osteolytic myeloma lesions

OBJECTIVE: We compared three magnetic resonance imaging (MRI) sequences-native zero echo time (ZTE), deep learning (DL)-chemical shift correction (CSC) reconstructed ZTE (ZTE-DLCSC), and gradient-echo black bone (BB)-in detecting osteolytic multiple myeloma (MM) lesions, using computed tomography (CT) as reference. MATERIALS AND METHODS: F-fluorodeoxiglucose-positron emission tomography/CT were prospectively enrolled at a single-center and underwent 3-T whole-body MRI with ZTE and BB sequences covering the lumbar spine, pelvis, and proximal femurs. ZTE-DLCSC images were reconstructed from raw data. Ten bone regions were assessed for lesion presence and number by a senior radiologist with 26 years' experience and two junior readers (a radiology fellow and a resident). Repeatability and reproducibility (Gwet's agreement coefficients AC1 and AC2), differences in quantitative counts, and accuracy were evaluated per-sequence/region/reader. RESULTS: Ten patients, aged 67 ± 12 years (mean ± standard deviation), were enrolled. Considering all regions, repeatability was at least moderate for ZTE (AC1 ≥ 0.45), good for ZTE-DLCSC and BB (AC1 ≥ 0.60) and very good for CT (AC1 ≥ 0.80). Reproducibility was at least fair for ZTE and BB (AC2 ≥ 0.20), good for ZTE-DLCSC (AC2 ≥ 0.60) and very good for CT (AC2 ≥ 0.80). Accuracy of ZTE-DLCSC ranged 80‒93%; compared to ZTE, accuracy increased by 23% and 25% for junior readers (p = 0.010 and p = 0.002 respectively) and by 32% for the senior reader (p < 0.001). ZTE-DLCSC detected more lesions than ZTE/BB (+30%, p = 0.011; +25%, p = 0.024). CONCLUSION: DL-driven DLCSC reconstruction improves the reliability and accuracy of the ZTE sequence for detecting MM lesions. RELEVANCE STATEMENT: The combination of deep learning reconstruction and chemical shift correction improves the accuracy of zero echo time MRI for detecting myeloma lesions. TRIAL REGISTRATION: This study was approved by the institutional ethics committee and registered at ClinicalTrials.gov (NCT05381077). KEY POINTS: The performance of ZTE-DLCSC for detecting osteolytic MM lesions was compared with that of native ZTE and BB sequences using CT as reference. ZTE-DLCSC showed better intra-reader agreement (repeatability) and inter-reader agreement (reproducibility) than ZTE and BB sequences. ZTE-DLCSC had fewer false positives and false negatives than ZTE and BB sequences. ZTE-DLCSC detected more lesions than ZTE and BB sequences.