压缩感知技术在踝关节 2D MR 成像中的应用.

BACKGROUND: At present, there are few reports on the application of compressed sensing technology in ankle MRI. OBJECTIVE: To investigate the effect of different acceleration factors in compressed sensing (CS) on image quality and scanning time of conventional 2D-MRI of the ankle joint. METHODS: Totally 24 healthy volunteers (38 ankles) underwent conventional 2D-TSE sequence scanning at 3.0T MR. Based on SENSE parallel imaging (S group) and compressed sensing technique (CS group), sequence images of T1WI-TRA (S1.3, CS1.3, CS1.9, CS2.7), PDWI-Dixon-SAG (S1.8, CS1.8, CS2.6, CS3.2) and PDWI-SPAIR-COR (S1.3, CS1.3, CS1.6, CS2.0) were obtained separately. Other scan parameters of each sequence remained consistent. The tendon, cartilage, ligament and muscle structures of the ankle joint images were subjectively scored by 5 points. The standard deviation of background noise and signal intensity of bone, cartilage, ligament, tendon, muscle, effusion and fat structures were measured, and the signal-to-noise ratio and contrast-to-noise ratio were calculated. The subjective score and objective evaluation of different acceleration factor images were statistically analyzed. SENSE group was used as the standard reference for the image quality of each sequence. RESULTS AND CONCLUSION: (1) When acceleration factor was the same, there were no statistically significant differences in subjective score, signal-to-noise ratio and contrast-to-noise ratio between the S group and the CS group (P > 0.05). (2) The acceleration factor of CS (TRA), CS (SAG) and CS (COR) sequences at CS1.9, CS2.6 and CS1.6 showed no significant difference in the image quality of cartilage, tendon, ligament and other main observed structures of the ankle joint (P > 0.05), and the scanning time was 1 minute and 32 seconds, 1 minute and 42 seconds, 1 minute and 48 seconds, respectively. When the acceleration factor of CS (TRA), CS (SAG) and CS (COR) sequences increased to CS2.7, CS3.2 and CS2.0, respectively, the subjective scores of all anatomical structures were still greater than 3, but signal-to-noise ratio and contrast-to-noise ratio of each sequence decreased significantly (P < 0.05). (3) These findings confirm that when acceleration factor is the same, compared with CS group, the image quality obtained by CS group is generally higher than that of S group. When acceleration factor increases, the scanning time of CS sequence decreases gradually, and the image quality also decreases. On a 3.0T MR, CS technology recommended CS1.9, CS2.6, and CS1.6 accelerators for conventional 2D sequences T1WI-TRA, PDWI-Dixon-SAG, and PDWI-SPAIR-COR, respectively, reducing the overall time by about 27% (1 minute and 53 seconds). [ABSTRACT FROM AUTHOR]