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Objective:To explore the feasibility of cardiac T 2 weighted dark blood sequence (T 2W-DB) based on artificial intelligence assisted compression-sensing(ACS) in clinical cardiac MR examination, compared with the conventional cardiac fast spin-echo T 2W-DB sequence. Methods:A total of 38 patients referred for cardiac MR examination in Tongji Hospital were enrolled prospectively from August to December 2021. The conventional T 2W-DB scan and the single-shot ACS T 2W-DB scan were acquired at continuous short-axial slices covering the whole left ventricle in all patients, and the acquisition time of each scan was recorded. The image quality of the two sequences was evaluated by the objective quantitative parameters and the subjective scoring methods, respectively. The signal to noise ratio (SNR), the contrast to noise ratio of the interventricular septum to blood pool (CNR), and the sharpness of the images were calculated. The subjective scoring was to evaluate the overall image quality, the effect of blood pool suppression, the visibility of right ventricular free wall, left ventricular free wall, and interventricular septum with a 5-point Likert scale. The intraclass correlation coefficient and Kendall W were calculated to evaluate the interobserver agreement of the objective quantitative parameters and subjective scoring. The paired t-test or Wilcoxon test was used to compare the difference in acquisition time, objective quantitative parameters and subjective scoring between the conventional T 2W-DB and the single-shot ACS T 2W-DB. Results:The inter-observer agreement between the single-shot ACS T 2W-DB and conventional T 2W-DB was good in all the objective quantitative parameters and subjective scoring of image quality ( P<0.05 for all). Compared with conventional T 2W-DB, acquisition time of single-shot ACS T 2W-DB was remarkably shortened [(85.8±14.7) s vs. (16.9±3.0) s, t=35.42, P<0.001]. Compared with SNR (66.4±29.0) and CNR(61.8±28.6) of conventional T 2W-DB, single-shot ACS T 2W-DB had significantly higher SNR(110.8±36.8, t=-8.13, P?0.001) and CNR(88.2±31.1, t=-5.89, P?0.001). Compared with conventional T 2W-DB, single-shot ACS T 2W-DB had better blood pool inhibition effect (4.6±0.6 vs. 4.7±0.5, Z=-2.64, P=0.008). There was no significant difference in overall image quality, visibility of right ventricular free wall, left ventricular free wall, and interventricular septum between the two sequences( P>0.05 for all). Conclusions:In cardiac MR examination, compared with the conventional T 2W-DB sequence, the single-shot ACS T 2W-DB sequence can significantly shorten the acquisition time and obtain better image quality.
RESUMO
Objective To study the diagnostic value of non-contrast T1mapping in left ventricular hypertrophy(LVH).Methods Forty LVH patients(LVH group)including 11 cardiac amyloidosis(CA),19 hypertrophic cardiomyopathy (HCM) and 10 hypertensive heart disease (HHD) patients, and 14 healthy volunteers (control group) were enrolled in this retrospective study between November 2015 and October 2016.All subjects underwent cardiac magnetic resonance(CMR)on a 3 T scanner.The CMR scan protocol included cine sequences, first-pass perfusion, late Gadolinium enhancement (LGE) and non-contrast T1 mapping(MOLLI)prototype sequences.The cardiac morphology was assessed by cine,first-pass perfusion as well as LGE.Left-ventricular end-diastolic wall thickness(EDTH)was assessed for 16 segments,native T1 values were measured in hypertrophic segments. The differences in EDTH and native T1values between LVH group and control group were evaluated using t test. The ANOVA and LSD were used in the comparison of differences among four sub-groups.Sensitivity,specificity,cut-off values and area under the curve (AUC) were derived using receiver-operating characteristics curve (ROC) analysis. Results The EDTH and native T1values in LVH group were significantly higher than those of control group[(16.5±5.2)mm vs.(6.3±1.8)mm,(1 388.6±119.8)ms vs.(1 248.4±58.1)ms,t=28.8 16.4,both P<0.01].Moreover,CA showed significantly higher T1value [(1 495.5 ± 100.9)ms] than that of HCM [(1 342.0 ± 69.2)ms] and HDD [(1 290.7±45.5)ms](F=300.5,P<0.01),and T1values in HCM were also higher than HDD(P<0.01).HCM showed significantly higher EDTH than that of CA and HDD (P<0.01), and EDTH in CA was also higher than HDD (P<0.01). The native T1showed good diagnostic performance between CA and HCM with AUC 0.914,sensitivity 90.1%%,and specificity 84.3%,and cutoff value 1 382.8 ms,between CA and HHD with AUC 0.989,sensitivity 97.0%,specificity 93.5% and cutoff value 1 359.5 ms.Conclusion The elevated native T1values were useful for quantitatively differential diagnosis of LVH.