Application Of The Magnetic Resonance BLADE Sequence And A Small FOV Surface Coil In Talus Cartilage Imaging

Objective:To explore the application value of a small FOV surface coil combined with the BLADE sequence in the magnetic resonance imaging of osteochondral lesions of the talar dome.Materials and Methods:From January 2017 to March 2019,20 volunteers and 43 patients underwent MRI scanning on the Avanto 1.5T MR.Application of coronal MR scan by the five different types of sequences:I – the routine FOV sequence of FSE-PD with a boot coil.II-the small FOV sequence of FSE-PD with a boot coil.III-the small FOV sequence of FSE-PD-BLADE with a boot coil.IV-the small FOV sequence of FSE-PD with a small FOV coil.V-the small FOV sequence of FSE-PD-BLADE with a small FOV coil.The imaging quality is compared from two aspectsObjective comparison: SNR and CNR of the talar cartilage were compared by 5 different kinds of MRI sequences of 20 ankle joints in the healthy volunteer group;Subjective comparison: ⑴Overall imaging differences between the volunteer group and the patient group: Whether there were differences in the overall display of cartilage MRI with five different kinds of MRI sequences using a four grade system;⑵Differences in detail display between five different kinds of MRI sequences: artifacts、the shape of bone edema、the degree of OLT、the location of OLT、the display of subchondral bone,these details on MR imaging in 43 OLT of ankle joints were compared using a five grade system.All MR images were evaluated independently by two radiologists.Results:In objective comparison,the highest SNR and CNR was sequence I using a routine FOV,followed by the small FOV sequence V,and the lowest values of cartilage SNR and CNR were sequence II,statistical significant differences were found between the each two comparisons for all sequences(p<0.05).In subjective comparison,(1)Overall display between the two groups,the scoring in the volunteer group were higher than the patient group except sequence II,and there were no statistical differences between the each corresponding sequence of two groups(p> 0.05).(2)The details of display between 5 sequences: The subjective score of two radiologists was kappa = 0.87,sequence IV,sequence V(small coil)were better than sequence II,sequence III(boot coil);Sequence III,sequence V(BLADE)were superior to sequence II,sequence IV(non-BLADE);Sequence V scored the highest in all aspects of imaging quality.For sequence V,there was no statistical difference(p= 0.838)only in the artifacts of Sequence III,and there were statistical differences compared any other sequences in all aspects of imaging quality(p< 0.05).Conclusion:Selection of the imaging parameters of a small FOV combined with the BLADE sequence using a small FOV surface coil can show the talar cartilage better.Objective:To compare the accuracy,sensitivity and specificity of fat suppressed proton density weighted imaging(FS PDWI)between a small FOV coil using blade sequences and a boot coil using routine sequences in displaying the OLT of ankle joints.Materials and Methods:This study included 101 patients,the clinical manifestations in 101 patients with ankle pain over six weeks and normal on the radiographs between January 2017 and October 2019.All patients were prepared to receive arthroscopic treatment for ankle joints after the scanning of MR.All patients were scanned by two different methods:(a)a coronal fat saturation FSE-PD blade sequence with a small FOV surface coil,(b)a coronal fat saturation FSE-PD routine sequence with a boot coil.In this study,the results of arthroscopy were regarded as the gold standard for the OLT,and were used to compare the accuracy,sensitivity and specificity of OLT between the two different MRI methods.Results:57 cases with cartilage injury and 44 cases without cartilage injury were confirmed by arthroscopy in 101 patients.In 57 patients of cartilage injury,the results were consistent with the findings of arthroscopy 48 patients in the blade sequence with a small FOV surface coil,and 37 patients in the routine FOV sequence with a boot coil.In the total of 101 cases,the weighted kappa = 0.803,accuracy = 90.10%,sensitivity = 84.21%,specificity = 97.73% between arthroscopy and the blade sequence with a small FOV coil,and weighted kappa = 0.515,accuracy = 75.25%,sensitivity = 64.91%,specificity = 88.64% between arthroscopy and the routine FOV sequence with a boot coil.The accuracy,sensitivity and specificity of the blade sequence with a small FOV coil were higher than the routine FOV sequence with a boot coil,and Mc Nemar test showed a significant difference between the two methods(p < 0.001).Conclusion:Compared with the scanning method of routine sequences in ankle joints,the blade sequence with a small FOV surface coil has higher accuracy,sensitivity and specificity in displaying the OLT.