Ultrashort echo time mri on cartilaginous endplates in lumbar spine / 中国医学影像技术

Objective: To explore the application value of MR ultrashort echo time (UTE) sequence and conventional sequence imaging for displaying lumbar intervertebral disc (IVD) cartilage endplate (CEP) injury. Methods: Totally 87 volunteers underwent conventional and UTE lumbar spine MRI. The correlation between UTE sequence of lumbar IVD CEP injury and vertebral Modic changes classification, Pfirrmann disc degeneration grade were analyzed. Results: UTE showed linear hyperintense uncalcified CEP and hypointense calcified CEP between nucleus pulposus and vertebral body. There was a positive correlation between cartilage endplate injury in L1-S1 and vertebral Modic changes classification, Pfirrmann disc degeneration grade (all P<0.001). Conclusion: MR UTE can clearly show the lamination and damage of CEP, and there is certain relationship between cartilage endplate injury and lumbar degeneration.

Ultrashort Echo Time MRI (UTE-MRI) Quantifications of Cortical Bone Varied Significantly at Body Temperature Compared with Room Temperature

PURPOSE: To investigate the temperature-based differences of cortical bone ultrashort echo time MRI (UTE-MRI) biomarkers between body and room temperatures. Investigations of ex vivo UTE-MRI techniques were performed mostly at room temperature however, it is noted that the MRI properties of cortical bone may differ in vivo due to the higher temperature which exists as a condition in the live body. MATERIALS AND METHODS: Cortical bone specimens from fourteen donors (63 ± 21 years old, 6 females and 8 males) were scanned on a 3T clinical scanner at body and room temperatures to perform T1, T2*, inversion recovery UTE (IR-UTE) T2* measurements, and two-pool magnetization transfer (MT) modeling. RESULTS: Single-component T2*, IR-T2*, short and long component T2*s from bi-component analysis, and T1 showed significantly higher values while the noted macromolecular fraction (MMF) from MT modeling showed significantly lower values at body temperature, as compared with room temperature. However, it is noted that the short component fraction (Frac1) showed higher values at body temperature. CONCLUSION: This study highlights the need for careful consideration of the temperature effects on MRI measurements, before extending a conclusion from ex vivo studies on cortical bone specimens to clinical in vivo studies. It is noted that the increased relaxation times at higher temperature was most likely due to an increased molecular motion. The T1 increase for the studied human bone specimens was noted as being significantly higher than the previously reported values for bovine cortical bone. The prevailing discipline notes that the increased relaxation times of the bound water likely resulted in a lower signal loss during data acquisition, which led to the incidence of a higher Frac1 at body temperature.

Detection of Repair of the Zone of Calcified Cartilage with Osteoarthritis through Mesenchymal Stem Cells by Ultrashort Echo Time Magnetic Resonance Imaging / 中华医学杂志(英文版)

<p><b>Objective</b>Currently, magnetic resonance imaging (MRI) is the most commonly used imaging modality for observing the growth and development of mesenchymal stem cells (MSCs) after in vivo transplantation to treat osteoarthritis (OA). However, it is a challenge to accurately monitor the treatment effects of MSCs in the zone of calcified cartilage (ZCC) with OA. This is especially true in the physiological and biochemical views that are not accurately detected by MRI contrast agents. In contrast, ultrashort time echo (UTE) MRI has been shown to be sensitive to the presence of the ZCC, creating the potential for more effectively observing the repair of the ZCC in OA by MSCs. A special focus is given to the outlook of the use of UTE MRI to detect repair of the ZCC with OA through MSCs. The limitations of the current techniques for clinical applications and future directions are also discussed.</p><p><b>Data Sources</b>Using the combined keywords: "osteoarthritis", "mesenchymal stem cells", "calcified cartilage", and "magnetic resonance imaging", the PubMed/MEDLINE literature search was conducted up to June 1, 2017.</p><p><b>Study Selection</b>A total of 132 published articles were initially identified citations. Of the 132 articles, 48 articles were selected after further detailed review. This study referred to all the important English literature in full.</p><p><b>Results</b>In contrast, UTE MRI has been shown to be sensitive to the presence of the ZCC, creating the potential for more effectively observing the repair of the ZCC in OA by MSCs.</p><p><b>Conclusions</b>The current studies showed that the ZCC could be described in terms of its histomorphology and biochemistry by UTE MRI. We prospected that UTE MRI has been shown the potential for more effectively observing the repair of the ZCC in OA by MSCs in vivo.</p>