Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 ...Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 yrs to 74 yrs were enrolled, gagCEST was acquired using a single-slice TSE sequence on a 3T. Saturation used a continuous rectangular RF pulse with B1=0.8 I^T and a fixed duration time =1100 ms. Sagittal image was obtained firstly without saturation pulse, and then saturated images were acquired at 52 offsets ranging from ＋0.i25 to ＋_7 parts per million （ppm）. MR T2 relaxivity map was acquired at the identical location. Six subjects were scanned twice to assess scan-rescan reproducibility. Results GagCEST intraclass correlation coefficient （ICC） of six subjects was 0.759 for nucleus pulposus （NP） and 0.508 for annulus fibrosus （AF）. Bland-Altman plots showed NP had a mean difference of 0.10% （95% limits of agreement： -3.02% to 3.22%）; while that of AF was 0.34% （95% limits of agreement： -2.28% to 2.95%）. For the 25 subjects, gag CEST in NP decreased as disc degeneration increased, with a similar trend to T2 relaxivity. Gag CEST of AF showed a better correlation with disc degeneration than T2 relaxivity. Conclusion GagCEST in NP and AF decreased as disc degeneration increased, while gagCEST in AF showed a better correlation than T2 relaxivity.展开更多
Attrition and eventual loss of articular cartilage are important elements in the pathophysiology of osteoarthritis(OA).Preventing the breakdown of cartilage is believed to be critical to preserve the functional integr...Attrition and eventual loss of articular cartilage are important elements in the pathophysiology of osteoarthritis(OA).Preventing the breakdown of cartilage is believed to be critical to preserve the functional integrity of a joint.Chondral injuries are also common in the knee joint,and many patients benefit from cartilage repair.Magnetic resonance imaging(MRI) and advanced digital post-processing techniques have opened possibilities for in vivo analysis of cartilage morphology,structure,and function in healthy and diseased knee joints.Techniques of semi-quantitative scoring of human knee cartilage pathology and quantitative assessment of human cartilage have been developed.Cartilage thickness and volume have been quantified in humans as well as in small animals.MRI detected cartilage loss has been shown to be more sensitive than radiographs detecting joint space narrowing.It is possible to longitudinally study knee cartilage morphology with enough accuracy to follow the disease-caused changes and also evaluate the therapeutic effects of chondro-protective drugs.There are also several MRI methods that may allow evaluation of the glycosaminoglycan matrix or collagen network of articular car-tilage,and may be more sensitive for the detection of early changes.The clinical relevance of these methods is being validated.With the development of new therapies for OA and cartilage injury,MR images will play an important role in the diagnosis,staging,and evaluation of the effectiveness of these therapies.展开更多
基金partially by grants from the Research Grants Council of the Hong Kong SAR,China(Project No.SEG_CUHK02)
文摘Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 yrs to 74 yrs were enrolled, gagCEST was acquired using a single-slice TSE sequence on a 3T. Saturation used a continuous rectangular RF pulse with B1=0.8 I^T and a fixed duration time =1100 ms. Sagittal image was obtained firstly without saturation pulse, and then saturated images were acquired at 52 offsets ranging from ＋0.i25 to ＋_7 parts per million （ppm）. MR T2 relaxivity map was acquired at the identical location. Six subjects were scanned twice to assess scan-rescan reproducibility. Results GagCEST intraclass correlation coefficient （ICC） of six subjects was 0.759 for nucleus pulposus （NP） and 0.508 for annulus fibrosus （AF）. Bland-Altman plots showed NP had a mean difference of 0.10% （95% limits of agreement： -3.02% to 3.22%）; while that of AF was 0.34% （95% limits of agreement： -2.28% to 2.95%）. For the 25 subjects, gag CEST in NP decreased as disc degeneration increased, with a similar trend to T2 relaxivity. Gag CEST of AF showed a better correlation with disc degeneration than T2 relaxivity. Conclusion GagCEST in NP and AF decreased as disc degeneration increased, while gagCEST in AF showed a better correlation than T2 relaxivity.
文摘Attrition and eventual loss of articular cartilage are important elements in the pathophysiology of osteoarthritis(OA).Preventing the breakdown of cartilage is believed to be critical to preserve the functional integrity of a joint.Chondral injuries are also common in the knee joint,and many patients benefit from cartilage repair.Magnetic resonance imaging(MRI) and advanced digital post-processing techniques have opened possibilities for in vivo analysis of cartilage morphology,structure,and function in healthy and diseased knee joints.Techniques of semi-quantitative scoring of human knee cartilage pathology and quantitative assessment of human cartilage have been developed.Cartilage thickness and volume have been quantified in humans as well as in small animals.MRI detected cartilage loss has been shown to be more sensitive than radiographs detecting joint space narrowing.It is possible to longitudinally study knee cartilage morphology with enough accuracy to follow the disease-caused changes and also evaluate the therapeutic effects of chondro-protective drugs.There are also several MRI methods that may allow evaluation of the glycosaminoglycan matrix or collagen network of articular car-tilage,and may be more sensitive for the detection of early changes.The clinical relevance of these methods is being validated.With the development of new therapies for OA and cartilage injury,MR images will play an important role in the diagnosis,staging,and evaluation of the effectiveness of these therapies.
