ObjectiveTo investigate the value of proton magnetic resonance spectroscopy (1H-MRS), gradient dual-echo, and triple-echo sequences in the quantitative evaluation of treatment effect of fatty liver at 3.0T MR.MethodsThirty patients with fatty liver diagnosed by CT or ultrasound who admitted in Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital between August 2017 and May 2018, were enrolled and undergone gradient dual-echo, triple-echo, and 1H-MRS examination before and 3 months after treatment. The fat index (FI) and relative lipid content (RLC) were measured. Fatty liver index (FLI) was calculated from blood biochemical indicators, waist circumference, and BMI at the same time. With the reference standard of FLI, the results before and after treatment measured from MRI were analyzed.ResultsThere were significantly differences of FLI, FIdual, FItriple, and RLC before and after treatment (t=5.281, P<0.001; Z=–3.651, P<0.001; Z=–3.630, P<0.001; Z=–4.762, P<0.001), all indexes decreased after treatment. FIdual and FItriple were positively correlated with FLI before (rs=0.413, P=0.023; rs=0.396, P=0.030) and after treatment (rs=0.395, P=0.031; rs=0.519, P=0.003), the highest correlation factor was FItriple to FLI after treatment. There were no significant correlation between RLC and FLI before and after treatment (P>0.05).ConclusionsIt is feasible to quantitatively evaluate the treatment effect of fatty liver by using 1H-MRS, gradient dual-echo, and triple-echo sequences. Gradient triple-echo sequences has better accuracy, which is technically easy to implement and more suitable for clinical development.
ObjectiveTo study the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting and evaluating the efficacy of neoadjuvant chemoradiotherapy (NCRT) in the middle-low locally advanced rectal cancer (LARC).MethodsThe patients were included prospectively who were clinically diagnosed as the LARC and were scheduled to undergo the NCRT and total mesorectal excision (TME) in the Sichuan Provincial People’s Hospital from February 2018 to November 2019. The routine MRI and DCE-MRI were performed before and after the NCRT, then the TME was performed. According to the score of tumor regression grade (TRG), the patients with TGR score of 0, 1 or 2 were classified as the response to NCRT group, and those with TRG score of 3 were classified as the non-response to NCRT group; in addition, the patients with TGR score of 0 or 1 were classified as the good-response group, with TRG score of 2 or 3 were classified as the poor-response group. The differences of quantitative perfusion parameters of DCE-MRI between two groups were compared, including the volume transfer constant (Ktrans), flux rate constant (Kep), and extravascular extracellular volume fraction (Ve) and the change rates of these parameters (ΔKtrans, ΔKep, and ΔVe).ResultsForty-one patients who met the inclusion criteria were included in this study, including 27 cases in the response to NCRT group and 14 cases in the non-response to NCRT group; 11 cases in the the good-response group and 30 cases in the poor-response group. ① The values of Ktrans before the NCRT and the ΔKtrans in the response to NCRT group were higher than those in the non-response to NCRT (P<0.05), while the other indexes had no significant differences between these two groups (P>0.05). The area under the receiver operating characteristic curve (AUCs) of Ktrans and ΔKtrans in predicting the efficacy of NCRT were 0.954 and 0.709, respectively. When the optimal thresholds of Ktrans and ΔKtrans were 0.122/min and –24.2%, the specificity and sensitivity were 85.7%, 96.3% and 100%, 51.7%, respectively. ② The Ktrans value in the good-response group was higher before NCRT and which was lower after NCRT as compared with the poor-response group (P<0.05). The absolute value of the the ΔKtrans and ΔKep in the good-response group were higher than those in the poor-response group (P<0.05). The other indexes had no significant differences between these two groups (P>0.05). The AUC of Ktrans before NCRT in predicting the efficacy of NCRT was 0.953. When the optimal thresholds of Ktrans before NCRT was 0.158 /min, the specificity and sensitivity were 88.7% and 90.9%, respectively. The AUC of ΔKtrans in predicting the efficacy of NCRT was higher than that of the ΔKep (0.952 versus 0.764, Z=2.063, P=0.039). When the optimal threshold of ΔKtrans was –38.8%, the specificity and sensitivity were 76.7% and 100%, respectively.ConclusionsDCE-MRI can predict and evaluate the effect of NCRT in patients with middle-low LARC, especially Ktrans and ΔKtrans (change rate before and after NCRT) have a high diagnostic efficiency.