Cardiac Magnetic Resonance in the Assessment of Chagas Disease and its Complications

Abstract The well-known occurrence of Chagas disease in endemic areas has become a worldwide problem, and cardiac magnetic resonance allows the early detection of cardiac involvement and complications of this disease. Cardiac magnetic resonance is a useful tool in all phases of Chagas disease, and new promising techniques using T1 mapping and extracellular volume measurements are able to detect cardiac involvement even earlier than conventional techniques.

Role of Myocardial Extracellular Volume Fraction Measured with Magnetic Resonance Imaging in the Prediction of Left Ventricular Functional Outcome after Revascularization of Chronic Total Occlusion of Coronary Arteries

OBJECTIVE: The purpose of this study was to prospectively investigate the value of the myocardial extracellular volume fraction (ECV) in predicting myocardial functional outcome after revascularization of coronary chronic total occlusion (CTO). MATERIALS AND METHODS: Thirty patients with CTO underwent cardiovascular magnetic resonance (CMR) before and 6 months after revascularization. Three baseline markers of functional outcome were evaluated in the dysfunctional segments assigned to the CTO vessels: ECV, transmural extent of infarction (TEI), and unenhanced rim thickness (RIM). At the global level, the ECV values of the whole myocardium with and without a hyperenhanced region (global and remote ECV) were respectively measured. RESULTS: In per-segment analysis, ECV was superior to TEI and RIM in predicting functional recovery (area under receiver operating characteristic curve [AUC]: 0.86 vs. 0.75 and 0.73, all p values < 0.010), and it emerged as the only independent predictor of regional functional outcome (odds ratio [OR] = 0.83, 95% confidence interval [CI]: 0.77–0.89; p < 0.001) independent of collateral circulation. In per-patient analysis, global baseline ECV was indicative of ejection fraction (EF) at the follow-up examination (β = −0.61, p < 0.001) and changes in EF (β = −0.57, p = 0.001) in multivariate regression analysis. A patient with global baseline ECV less than 30.0% (AUC, 0.93; sensitivity 94%, specificity 80%) was more likely to demonstrate significant EF improvement (OR: 0.38; 95% CI: 0.17–0.85; p = 0.019). CONCLUSION: Extracellular volume fraction obtained by CMR may provide incremental value for the prediction of functional recovery both at the segmental and global levels in CTO patients, and may facilitate the identification of patients who can benefit from revascularization.

Application progresses of new cardiovascular MR techniques on valvular heart disease / 中国医学影像技术

Valvular heart disease (VHD) is one kind of the main causes of cardiovascular events in the elderly patients. Cardiac imaging evaluation plays a critical role in the diagnosis and selection of treatment options for VHD. New cardiovascular MR (CMR) techniques have been increasingly used for VHD patients, of which 4D Flow MRI-derived hemodynamic parameters can be used to estimate transvalvular blood flow velocities, pressure gradients, wall shear stress and flow patterns, T1 mapping and extracellular volume fraction enable quantification of changes of early ventricular remodeling secondary to VHD, strain analysis can be used to assess early myocardial dysfunction. The application progresses of new CMR techniques on VHD were reviewed in this article.

The value of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced T1 mapping MRI in the quantitative evaluation of hepatic fibrosis in patients with hepatitis B / 中华放射学杂志

Objective@#To investigate the quantitative evaluation efficiency of gadolinium- ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) enhanced T1 mapping in staging hepatic fibrosis caused by viral hepatitis B.@*Methods@#One hundred and fifty patients with chronic hepatitis B were prospectively enrolled in Shanghai Public Health Clinical Center, Fudan University from August 2016 to August 2018.These patients underwent liver aspiration biopsy were divided into four subgroups: S1 (n=38), S2 (n=30), S3 (n=33), S4 (n=49) according to Scheuer-Ludwig scoring system. Non-enhanced and Gd-EOB-DTPA-enhanced MRI were performed in all subjects. Look-Locker sequences were performed to acquire T1 mapping of pre and post-contrast at 20 minutes after Gd-EOB-DTPA administration. The T1 value after 20 minutes of Gd-EOB-DTPA administration (T1 20 min), the reduction rate of T1 value (ΔT1 20 min%), the increase of 1/T1 value (ΔR1 20 min%) were measured and calculated. The one-way ANOVA was applied to compare the difference in T1 20 min, ΔT1 20 min%, ΔR1 20 min% of various fibrosis stages. ROC curves were used to assess the efficacy of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing ≥ S2, ≥ S3, ≥ S4. P<0.05 was considered to be statistically significant.@*Results@#The T1 20 min raised with fibrosis stage increased, ΔT1 20 min% and ΔR1 20 min% reduced with fibrosis stage increased. Areas under the curves of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing ≥ S2 were 0.844, 0.905, 0.869; and diagnosing ≥ S3 were 0.832, 0.907, 0.862; and diagnosing ≥ S4 were 0.853, 0.897, 0.873, respectively. The diagnostic efficiency of ΔT1 20 min% was the best.@*Conclusion@#Gd-EOB-DTPA-enhanced T1 mapping could be regarded as a reliable diagnostic tool for the evaluation of hepatic fibrosis caused by viral hepatitis B.

Late gadolinium enhancement and T1 mapping for the diagnosis of cardiac amyloidosis / 中华危重病急救医学

Objective@#To explore the role of late gadolinium enhancement (LGE) and T1 mapping for detection of cardiac amyloidosis.@*Methods@#Nine cases of cardiac amyloidosis who had diagnosed by renal biopsy diagnosed type light-chain (AL) amyloidosis and acute heart failure suspected involvement of the heart in Tianjin First Central Hospital from May 2018 to March 2019 were enrolled, and at the same time 14 cases of non-obstructive hypertrophic cardiomyopathy patients, 12 cases of healthy physical examination at the same period were enrolled as the control. All patients underwent Philips 3.0-T including plain scan as cine, T2WI, native T1 mapping and enhanced scan as perfusion, LGE imaging, post T1 mapping. For LGE cardiac magnetic resonance imaging (CMRI), a bolus of 0.1 mL/kg of gadolinium-based contrast followed by a 20 mL saline flush was administered. After a 7-minutes delay, ECG-gated images were acquired in 3 long-axis and a stack of short-axis slices identical to those of cine images using a breath-hold gradient recalled echo phase-sensitive or magnitude only inversion recovery sequence. LGE and T1 mapping CMRI observation, including cardiac function index [left ventricle end-diastolic volume (LVEDV), left ventricle end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), valvular regurgitation], cardiac morphological index [including left ventricular wall thickness, left ventricular weight (LVM)], myocardial histological characteristics and markers N-terminal pro-brain natriuretic peptide (NT-proBNP) and accompanying signs (including pericardial effusion, pleural effusion) were performed.@*Results@#The predominant LGE pattern in amyloidosis was diffuse left ventricular sub endocardial enhancement (3/9), diffuse in left ventricular wall enhancement (3/9), and transmural delayed enhancement in left ventricular (2/9) and non-typical delayed enhancement (1/9). Myocardial T1 was significantly elevated in cardiac AL amyloidosis patients compared to normal subjects and hypertrophic cardiomyopathy (ms: 1 497.3±22.0 vs. 1 273.3±30.1, 1 329.3±42.6, both P < 0.05). Myocardial T1 was increased in AL amyloid before LGE. A post-contrast myocardial T1 was significantly elevated in cardiac AL amyloidosis patients compared to normal subjects and hypertrophic cardiomyopathy (ms: 476.7±44.2 vs. 516.1±41.5, 569.9±12.3, both P > 0.05). Three of 9 amyloidosis patients with review images showing T1 value and cardiac function was no significantly different with the first check (ms: 1 484.8±6.5 vs. 1 497.3±22.0, P = 0.11).@*Conclusions@#One-stop CMRI can improve the diagnosis of cardiac amyloidosis, LGE can display the myocardial scarring and fibrosis, and T1 mapping is sensitive to myocardial edema and diffuse fibrosis. LGE and T1 mapping can improve the diagnostic accuracy, which is very meaningful for diagnosis and follow-up of patients.

The value of gadolinium?ethoxybenzyl?diethylenetriamine pentaacetic acid enhanced T1 mapping MRI in the quantitative evaluation of hepatic fibrosis in patients with hepatitis B / 中华放射学杂志

Objective To investigate the quantitative evaluation efficiency of gadolinium?ethoxybenzyl?diethylenetriamine pentaacetic acid (Gd?EOB?DTPA) enhanced T1 mapping in staging hepatic fibrosis caused by viral hepatitis B. Methods One hundred and fifty patients with chronic hepatitis B were prospectively enrolled in Shanghai Public Health Clinical Center, Fudan University from August 2016 to August 2018.These patients underwent liver aspiration biopsy were divided into four subgroups: S1 (n=38), S2 (n=30), S3 (n=33), S4 (n=49) according to Scheuer?Ludwig scoring system. Non?enhanced and Gd?EOB?DTPA?enhanced MRI were performed in all subjects. Look?Locker sequences were performed to acquire T1 mapping of pre and post?contrast at 20 minutes after Gd?EOB?DTPA administration. The T1 value after 20 minutes of Gd?EOB?DTPA administration (T1 20 min), the reduction rate of T1 value (ΔT1 20 min% ), the increase of 1/T1 value (ΔR1 20 min% ) were measured and calculated. The one?way ANOVA was applied to compare the difference in T1 20 min, ΔT1 20 min%, ΔR1 20 min% of various fibrosis stages. ROC curves were used to assess the efficacy of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing≥S2,≥S3,≥S4. P<0.05 was considered to be statistically significant. Results The T1 20 min raised with fibrosis stage increased, ΔT1 20 min% and ΔR1 20 min% reduced with fibrosis stage increased. Areas under the curves of T1 20 min, ΔT1 20 min%, ΔR1 20 min% for diagnosing≥S2 were 0.844, 0.905, 0.869; and diagnosing≥S3 were 0.832, 0.907, 0.862; and diagnosing≥S4 were 0.853, 0.897, 0.873, respectively. The diagnostic efficiency of ΔT1 20 min% was the best. Conclusion Gd?EOB?DTPA?enhanced T1 mapping could be regarded as a reliable diagnostic tool for the evaluation of hepatic fibrosis caused by viral hepatitis B.

Late gadolinium enhancement and T1 mapping for the diagnosis of cardiac amyloidosis / 中华危重病急救医学

Objective To explore the role of late gadolinium enhancement (LGE) and T1 mapping for detection of cardiac amyloidosis. Methods Nine cases of cardiac amyloidosis who had diagnosed by renal biopsy diagnosed type light-chain (AL) amyloidosis and acute heart failure suspected involvement of the heart in Tianjin First Central Hospital from May 2018 to March 2019 were enrolled, and at the same time 14 cases of non-obstructive hypertrophic cardiomyopathy patients, 12 cases of healthy physical examination at the same period were enrolled as the control. All patients underwent Philips 3.0-T including plain scan as cine, T2WI, native T1 mapping and enhanced scan as perfusion, LGE imaging, post T1 mapping. For LGE cardiac magnetic resonance imaging (CMRI), a bolus of 0.1 mL/kg of gadolinium-based contrast followed by a 20 mL saline flush was administered. After a 7-minutes delay, ECG-gated images were acquired in 3 long-axis and a stack of short-axis slices identical to those of cine images using a breath-hold gradient recalled echo phase-sensitive or magnitude only inversion recovery sequence. LGE and T1 mapping CMRI observation, including cardiac function index [left ventricle end-diastolic volume (LVEDV), left ventricle end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), valvular regurgitation], cardiac morphological index [including left ventricular wall thickness, left ventricular weight (LVM)], myocardial histological characteristics and markers N-terminal pro-brain natriuretic peptide (NT-proBNP) and accompanying signs (including pericardial effusion, pleural effusion) were performed. Results The predominant LGE pattern in amyloidosis was diffuse left ventricular sub endocardial enhancement (3/9), diffuse in left ventricular wall enhancement (3/9), and transmural delayed enhancement in left ventricular (2/9) and non-typical delayed enhancement (1/9). Myocardial T1 was significantly elevated in cardiac AL amyloidosis patients compared to normal subjects and hypertrophic cardiomyopathy (ms: 1497.3±22.0 vs. 1273.3±30.1, 1329.3±42.6, both P < 0.05). Myocardial T1 was increased in AL amyloid before LGE. A post-contrast myocardial T1 was significantly elevated in cardiac AL amyloidosis patients compared to normal subjects and hypertrophic cardiomyopathy (ms: 476.7±44.2 vs. 516.1±41.5, 569.9±12.3, both P > 0.05). Three of 9 amyloidosis patients with review images showing T1 value and cardiac function was no significantly different with the first check (ms: 1484.8±6.5 vs. 1497.3±22.0, P = 0.11). Conclusions One-stop CMRI can improve the diagnosis of cardiac amyloidosis, LGE can display the myocardial scarring and fibrosis, and T1 mapping is sensitive to myocardial edema and diffuse fibrosis. LGE and T1 mapping can improve the diagnostic accuracy, which is very meaningful for diagnosis and follow-up of patients.

Gadoxetic disodium-enhanced MRI to characterize T1 relaxation values and expression level of organic anion transporters and multidrug resistance protein on hepatocyte surface membrane of normal C57BL/6 mice / 中华肝脏病杂志

Objective@#The characteristics of T1 relaxation values and the expression levels of organic anion transport system (OATP) and multidrug resistance protein carrier (MRP) on hepatocyte surface membrane were quantitatively studied to evaluate liver function in normal C57BL/6 mice with gadoxetic disodium-enhanced MRI.@*Methods@#Ten 6-weeks-old, normal C57BL/6 mice were included in this study. Gadoxetic disodium- enhanced MRI examination was performed. Longitudinal relaxation time images before and 20 min after contrast injection (hepatobiliary-specific phase) were acquired. T1-relaxation time, T1 relaxation time decline rate (△T) and rapid initial enhancement slope percentage in the first-pass study of the liver parenchyma before and after administration of gadoxetate disodium were measured. Liver parenchyma specimens were detected by Western blotting and the values ​​of OATP1, MRP2, and MRP3 were recorded. Statistical results were expressed in mean.@*Results@#The mean T1 relaxation time of 10 normal C57BL/6 mice before and after enhancement was 659.13 ± 24.07, and 408.87 ± 27.21 ms. The mean T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study was 37.12% ± 4.95% and 4.14% ± 0.96% ms. Furthermore, the mean value of OATP1, MRP2 and MRP3 were 29 952.1 ± 11 475.2, 34 376.4 ± 33 228.4 and 357 308.9 ± 64 646.5.@*Conclusion@#T1-relaxation values, T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study before and after gadoxetic disodium-enhanced MRI were determined in normal C57BL/6 mice as well as quantitative values of OATP1, MRP2 and MRP3 at the molecular level on the hepatocyte surface membrane were helpful for liver injury model with control study.

RE: Prediction of the Left Ventricular Functional Outcome by Myocardial Extracellular Volume Fraction Measured Using Magnetic Resonance Imaging: Methodological Issue

No abstract available.

The value of contrast?enhanced T1 mapping technique in differentiating recurrence and radiation necrosis of brain metastases after gamma knife treatment / 中华放射学杂志

Objective To explore the value of contrast?enhanced T1 mapping technique in differentiating between recurrence and radiation necrosis of brain metastases after gamma knife treatment. Methods From March 2016 to June 2017,56 patients with brain metastases treated by gamma knife and confirmed by pathology or follow?up in Shandong Provincial Hospital were prospectively collected. Routine MRI and contrast?enhanced T1 mapping sequence scan were performed. T1 value was obtained 5 mins (T1 5 min) and 60 mins (T1 60 min) after injection of contrast agent. The Differences betweenT1 60 min and T1 5 min (T1 differ) was calculated,and relative cerebral blood volume (rCBV) value was obtained. Patients were divided into radiation necrosis group and tumor recurrence group according to imaging follow?up results or pathological results. Two?sides unpaired t test was used to compare the differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups. Pearson correlation analysis was used to evaluate the correlation between T1 differ and rCBV, and the receiving operating curve (ROC) was used to evaluate the diagnostic efficiency of MRI quantitative parameters,and Z test was used to compare the differences of area under curve (AUC) between T1 differ and rCBV values. Results Of the 56 patients,27 had tumor recurrence and 29 had radiation necrosis. The differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups was statistically significant (P<0.05). T1 differ and rCBV values were significantly correlated, r=0.58, P<0.01. The differential diagnosis of AUC between radiation necrosis and tumor recurrence were 0.66,0.73,0.97 and 0.95 respectively in T1 5 min,T1 60 min, T1 differ and rCBV, and there was no significant differences between AUC in T1 differ and rCBV (P=0.274). Conclusion The contrast?enhanced T1 mapping image can be used for differential diagnosis between radiation necrosis and recurrence after gamma knife treatment of brain metastases. T1 differ value has high differential efficiency.

Value of gadoxetate disodium-enhanced magnetic resonance on hepatobiliary phase T1 mapping for predicting liver injury / 中华肝脏病杂志

Objective@#To evaluate the measured value of gadoxetic disodium - enhanced T1-weighted magnetic resonance for the prediction of liver damage (LD) including liver fibrosis and inflammation.@*Methods@#Retrospectively analyzed laboratory data of 115 patients with pathological results including prothrombin time (PT), albumin, serum total bilirubin level (TBil), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and magnetic resonance measurements (T1 measurement before and after enhancement and hepatobiliary specific phase T1pre, T1post, and changes in T1 relaxation time before and after enhancement were measured). The correlation between LD and magnetic resonance measurements was assessed by Spearman’s correlation. All cases were divided into two groups: LD < 1 and LD≥1 (n1 = 26, n2 = 89), and the mean value of both groups was compared by t-test or Mann-Whitney U test. The independent influence factors of LD were obtained by binary logistic regression model. The area under receiver operating characteristics (AUROC) curve was performed on T1pre, T1post, and variation values.@*Results@#Spearman's correlation test showed that T1post and variation values ​​were significantly associated with LD, and the correlation coefficients were 0.435, -0.353 and P < 0.05, respectively. The mean values ​​of T1post, variation values, PT, albumin, ALT and AST were statistically significant (P < 0.05). Binary logistic regression model showed T1post (P = 0.006), PT (P = 0.003), and AST (P = 0.032) were independent influencing factors of LD. T1- post contrast was good predictor of liver damage (AUC = 0.800).@*Conclusion@#T1-post contrast predicts the existence of liver damage and provides useful information for clinical diagnosis and treatment.

Contour-based Registration for Left Ventricular Myocardial Extracellular Volume Fraction Using T1 Mapping in Healthy Adults / 中山大学学报(医学科学版)

[Objective]We aimed to evaluate the role of contour-based registration in quantification of myocardial extracellular volume fraction(ECV)based on T1 mapping technique.[Methods]T1 mapping images of the basal,mid-cavity and apical short axis slices of 26 healthy volunteers(16 males and 10 females)were obtained before and after administration of contrast agent using Modified Look-Locker Inversion Recovery(MOLLI)on a 3.0T Magnetic Resonance Imaging system.ECV was calculated by routine method and registered method.For each slice,subjects were divided into the deformation subgroup and the control subgroup.Routine ECVs and registered ECVs were compared for each subgroup.[Results]Left ventricular deformation among T1 mapping images occurred in 16 subjects(61.5%). In all three slices, registered ECV maps had better image quality and more highest grade images than routine ECV maps. Routine ECVs[(26.81 ± 2.78)%,(25.38 ± 3.05)%,(28.66 ± 4.10)%]were statistically different from registered ECVs in global [(25.75±2.42)%,P=0.001],mid-cavity[(24.30±2.45)%,P=0.016]and apical slices[(27.22±3.38)%,P=0.010]. In deformation subgroups of all the 3 slices,registered ECVs were lower than routine ECVs with smaller SDs(P=0.038, 0.012,0.016).The apical ECVs were higher with larger SDs than the other two slices and the global ECVs(routine:F=4.799,P=0.004;registered:F=4.822,P=0.003).[Conclusions]Contour-based registration can improve the image qual-ity and precision of ECV quantification in cases with ventricular shape deformation among source images.

Quantitative analysis of left ventricle myocardial fibrosis in patients with atrial fibrillation by cardiac MRI / 中国医学影像技术

Objective To evaluate the diffuse myocardial fibrosis of the left ventricle (LV) in patients with atrial fibrillation (AF) by cardiac MR (CMR) T1 mapping methods.Methods Totally 60 subjects (30 paroxysmal AF patients and 30 persistent AF patients) and 59 normal control underwent MR cardiac cine,late gadolinium enhancement,and LV T1 mapping.For T1 mapping,modified Look-Locker inversion recovery sequence was used.Compared with control,pre-contrast ventricular T1 times were quantified and extracellular volume (ECV) was calculated.Results All subjects completed the CMR exam,no myocardial delay enhanced lesion was found.Pre-contrast ventricular T1 time in healthy controls was lower than that in patients with persistent and paroxysmal AF,and the pre-comrast ventricular T1 time in persistent AF patients was higher than that of paroxysmal AF patients (all P＜0.05).The mean LV myocardial ECV had no statistical difference between healthy controls and paroxysmal AF patients (P＞ 0.05),while lower than persistent AF patients (P ＜ 0.05).The mean LV myocardial ECV in patients with persistent AF was larger than that in patients with paroxysmal AF (P＜0.05).LV functional indexes were positive correlated with pre-contrast ventricular T1 time and ECV in patients with AF (all P＜0.05).Conclusion There is LV myocardial fibrosis in patients with AF,and the degree in patients with persistent AF is more severe than that in patients with paroxysmal AF.

Experimental study on acute hypertensive cerebral edema at 7.0T MR / 实用放射学杂志

Objective To verify the feasibility of a rat model of acute hypertension, and to observe the imaging findings at 7.0T MR scanner of the model.Methods In experimental group, the rats were scanned at 7.0T Bruker MR scanner when phenylephrine was injected continuously to evoke an acute hypertension state.The real time blood pressure was monitored through a femoral arterial catheter connected to a pressure transducer.The control group was infused with saline.T2WI, DWI and T1 mapping were performed in the two rat groups.ADC maps and T1 maps were acquired after image post-processing, and a voxel wise analysis and a ROI analysis were applied.The brain morphology change was evaluated by HE staining.The blood-brain barrier permeability was evaluated by Evans blue staining.Results The T2 images and DWI images of the experiment group showed no abnormal signal intensity changes observed by naked eyes.But ROI analysis of the ADC maps showed that the brain ADC values of the experiment group was higher than the control group (t=3.291,P0.05).The blue dye region was only performed in the experimental group,the results of HE staining corresponded with vasogenic brain edema.Conclusion Continuous infusing of phenylephrine hydrochloride can induce a rat model of acute hypertension.Vasogenic edema and blood-brain barrier permeability change can be observed in the rat model, and the imaging distribution of vasogenic edema can be detected by MRI.

Myocardial T1 and T2 Mapping: Techniques and Clinical Applications

Cardiac magnetic resonance (CMR) imaging is widely used in various medical fields related to cardiovascular diseases. Rapid technological innovations in magnetic resonance imaging in recent times have resulted in the development of new techniques for CMR imaging. T1 and T2 image mapping sequences enable the direct quantification of T1, T2, and extracellular volume fraction (ECV) values of the myocardium, leading to the progressive integration of these sequences into routine CMR settings. Currently, T1, T2, and ECV values are being recognized as not only robust biomarkers for diagnosis of cardiomyopathies, but also predictive factors for treatment monitoring and prognosis. In this study, we have reviewed various T1 and T2 mapping sequence techniques and their clinical applications.

Effect of Levothyroxine Replacement Therapy on Improving Diffused Left Ventricular Myocardial Lesions in Patients With Hypothyroidism / 中国循环杂志

Objective: To study the effect of levothyroxine replacement therapy on improving diffused left ventricular myocardial lesions and cardiac function in patients with hypothyroidism. Methods: Our research included 2 groups: Hypothyroidism group,n=20 newly diagnosed patients and Control group, n=17 normal healthy subjects. Diffused left ventricular myocardial lesions were quantitatively evaluated by non-invasive cardiac MRI T1 mapping technique. Left ventricular myocardial T1 value and left ventricular function before and after levothyroxine replacement therapy were compared; the relationship between T1 value and thyroid function and the relationship between T1 value and the indicators of left ventricular function were analyzed. Results:①Compared with Control group, Hypothyroidism group had increased left ventricular myocardial T1 value, P<0.01, while decreased cardiac index (CI) and left ventricular peak filling rate (PFR), allP<0.05.②In patients with hypothyroidism, left ventricular myocardial T1 value was negatively related to serum FT3 level (r=-0.52,P=0.0006) and PFR (r=-0.43,P=0.0085).③Compared with pre-therapeutic condition, the patients with recovered normal thyroid function showed obviously decreased left ventricular myocardial T1 value and improved CI, PFR. Conclusion: Levothyroxine replacement therapy may improve diffused left ventricular myocardial lesions in patients with hypothyroidism, and therefore improve the cardiac function.

Progress of myocardial T1 mapping technique and clinical applications / 医学研究生学报

T1 mapping is a new magnetic resonance imaging technique .By which the longitudinal relaxation time constant ( T1) of the myocardium can be measured to detect and quantitatively assess various focal or diffuse diseases .T1 mapping has various scan sequences , such as LL sequence , MOLLI sequence and ShMOLLI sequence .T1 mapping can be classified into two groups:pre--contrast and post-contrast T1 mapping.In addition, by measuring post-contrast T1 mapping and pre-contrast T1 mapping, myocardial extra-cellular volume (ECV) can be derived, which has been applied to assess myocardial edema and myocardial fibrosis with great clinical value .This review focuses on the techniques , methods and clinical application of cardiac magnetic resonance T 1 mapping technology .

Relationship between Myocardial Extracellular Space Expansion Estimated with Post-Contrast T1 Mapping MRI and Left Ventricular Remodeling and Neurohormonal Activation in Patients with Dilated Cardiomyopathy

OBJECTIVE: Post-contrast T1 values are closely related to the degree of myocardial extracellular space expansion. We determined the relationship between post-contrast T1 values and left ventricular (LV) diastolic function, LV remodeling, and neurohormonal activation in patients with dilated cardiomyopathy (DCM). MATERIALS AND METHODS: Fifty-nine patients with DCM (mean age, 55 +/- 15 years; 41 males and 18 females) who underwent both 1.5T magnetic resonance imaging and echocardiography were enrolled. The post-contrast 10-minute T1 value was generated from inversion time scout images obtained using the Look-Locker inversion recovery sequence and a curve-fitting algorithm. The T1 sample volume was obtained from three interventricular septal points, and the mean T1 value was used for analysis. The N-Terminal pro-B-type natriuretic peptide (NT-proBNP) level was measured in 40 patients. RESULTS: The mean LV ejection fraction was 24 +/- 9% and the post-T1 value was 254.5 +/- 46.4 ms. The post-contrast T1 value was significantly correlated with systolic longitudinal septal velocity (s'), peak late diastolic velocity of the mitral annulus (a'), the diastolic elastance index (Ed, [E/e']/stroke volume), LV mass/volume ratio, LV end-diastolic wall stress, and LV end-systolic wall stress. In a multivariate analysis without NT-proBNP, T1 values were independently correlated with Ed (beta = -0.351, p = 0.016) and the LV mass/volume ratio (beta = 0.495, p = 0.001). When NT-proBNP was used in the analysis, NT-proBNP was independently correlated with the T1 values (beta = -0.339, p = 0.017). CONCLUSION: Post-contrast T1 is closely related to LV remodeling, diastolic function, and neurohormonal activation in patients with DCM.