Prognostic Value of Left Ventricular Longitudinal Function and Myocardial Fibrosis in Patients With Ischemic and Non-Ischemic Dilated Cardiomyopathy Concomitant With Type 2 Diabetes Mellitus: A 3.0 T Cardiac MR Study.

BACKGROUND: Poorly controlled type 2 diabetes mellitus (T2DM) is known to result in left ventricular (LV) dysfunction, myocardial fibrosis, and ischemic/nonischemic dilated cardiomyopathy (ICM/NIDCM). However, less is known about the prognostic value of T2DM on LV longitudinal function and late gadolinium enhancement (LGE) assessed with cardiac MRI in ICM/NIDCM patients. PURPOSE: To measure LV longitudinal function and myocardial scar in ICM/NIDCM patients with T2DM and to determine their prognostic values. STUDY TYPE: Retrospective cohort. POPULATION: Two hundred thirty-five ICM/NIDCM patients (158 with T2DM and 77 without T2DM). FIELD STRENGTH/SEQUENCE: 3T; steady-state free precession cine; phase-sensitive inversion recovery segmented gradient echo LGE sequences. ASSESSMENT: Global peak longitudinal systolic strain rate (GLPSSR) was evaluated to LV longitudinal function with feature tracking. The predictive value of GLPSSR was determined with ROC curve. Glycated hemoglobin (HbA1c) was measured. The primary adverse cardiovascular endpoint was follow up every 3 months. STATISTICAL TESTS: Mann-Whitney U test or student's t-test; Intra and inter-observer variabilities; Kaplan-Meier method; Cox proportional hazards analysis (threshold = 5%). RESULTS: ICM/NIDCM patients with T2DM exhibited significantly lower absolute value of GLPSSR (0.39 ± 0.14 vs. 0.49 ± 0.18) and higher proportion of LGE positive (+) despite similar LV ejection fraction, compared to without T2DM. LV GLPSSR was able to predict primary endpoint (AUC 0.73) and optimal cutoff point was 0.4. ICM/NIDCM patients with T2DM (GLPSSR < 0.4) had more markedly impaired survival. Importantly, this group (GLPSSR < 0.4, HbA1c ≥ 7.8%, or LGE (+)) exhibited the worst survival. In multivariate analysis, GLPSSR, HbA1c, and LGE (+) significantly predicted primary adverse cardiovascular endpoint in overall ICM/NIDCM and ICM/NIDCM patients with T2DM. CONCLUSIONS: T2DM has an additive deleterious effect on LV longitudinal function and myocardial fibrosis in ICM/NIDCM patients. Combining GLPSSR, HbA1c, and LGE could be promising markers in predicting outcomes in ICM/NIDCM patients with T2DM. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: 5.

Quantification of Early Diffuse Myocardial Fibrosis Through 7.0 T Cardiac Magnetic Resonance T1 Mapping in a Type 1 Diabetic Mellitus Mouse Model.

BACKGROUND: Diffuse myocardial interstitial fibrosis (DMIF) is a key factor for heart failure (HF) in diabetic cardiomyopathy. MRI T1-mapping technique can quantitatively evaluate DMIF. PURPOSE: To evaluate of early DMIF in a type 1 diabetes mellitus (T1DM) mouse model through 7.0 T MRI T1 mapping. STUDY TYPE: Prospective. ANIMAL MODEL: A total of 50 8-week-old C57Bl/6J male mice were divided into control (n = 20) and T1DM (n = 30) groups. FIELD STRENGTH/SEQUENCE: A 7.0 T small animal MRI; gradient echo Look-Locker inversion recovery T1-mapping sequence; cine MRI. Scans were acquired in control and T1DM mice every 4 weeks until 24 weeks. ASSESSMENT: End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), left ventricle (LV) mass, fractional shortening (FS), and E/A ratio. They were evaluated through echocardiography and cine MRI. The extracellular volume fraction (ECV) was calculated. Sirius Red staining was performed and calculated collagen volume fraction (CVF). STATISTICAL TESTS: Differences in ECV and CVF between two groups were analyzed using one-way analysis of variance. The correlation between ECV and CVF was assessed using Pearson's correlations. RESULTS: Compared with the control group, a progressive decrease in FS, EF, and E/A ratio was observed in the T1DM group. Both ECV and CVF values gradually increased during diabetes progression. A significant increase in ECV and CVF values was observed at 12 weeks (ECV: 32.5% ± 1.6% vs. 28.1% ± 1.8%; CVF: 6.9% ± 1.8% vs. 3.3% ± 1.1%). ECV showed a strong correlation with CVF (r = 0.856). DATA CONCLUSION: ECV is an accurate and feasible imaging marker that can be used to quantitatively assess DMIF changes over time in T1DM mice. ECV has potential to accurately detect DMIF in the early stage and may be a useful imaging tool to assess the need for early intervention in T1DM mice. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 3.

Deep Learning for Diagnosis of Chronic Myocardial Infarction on Nonenhanced Cardiac Cine MRI.

Background Renal impairment is common in patients with coronary artery disease and, if severe, late gadolinium enhancement (LGE) imaging for myocardial infarction (MI) evaluation cannot be performed. Purpose To develop a fully automatic framework for chronic MI delineation via deep learning on non-contrast material-enhanced cardiac cine MRI. Materials and Methods In this retrospective single-center study, a deep learning model was developed to extract motion features from the left ventricle and delineate MI regions on nonenhanced cardiac cine MRI collected between October 2015 and March 2017. Patients with chronic MI, as well as healthy control patients, had both nonenhanced cardiac cine (25 phases per cardiac cycle) and LGE MRI examinations. Eighty percent of MRI examinations were used for the training data set and 20% for the independent testing data set. Chronic MI regions on LGE MRI were defined as ground truth. Diagnostic performance was assessed by analysis of the area under the receiver operating characteristic curve (AUC). MI area and MI area percentage from nonenhanced cardiac cine and LGE MRI were compared by using the Pearson correlation, paired t test, and Bland-Altman analysis. Results Study participants included 212 patients with chronic MI (men, 171; age, 57.2 years ± 12.5) and 87 healthy control patients (men, 42; age, 43.3 years ± 15.5). Using the full cardiac cine MRI, the per-segment sensitivity and specificity for detecting chronic MI in the independent test set was 89.8% and 99.1%, respectively, with an AUC of 0.94. There were no differences between nonenhanced cardiac cine and LGE MRI analyses in number of MI segments (114 vs 127, respectively; P = .38), per-patient MI area (6.2 cm2 ± 2.8 vs 5.5 cm2 ± 2.3, respectively; P = .27; correlation coefficient, r = 0.88), and MI area percentage (21.5% ± 17.3 vs 18.5% ± 15.4; P = .17; correlation coefficient, r = 0.89). Conclusion The proposed deep learning framework on nonenhanced cardiac cine MRI enables the confirmation (presence), detection (position), and delineation (transmurality and size) of chronic myocardial infarction. However, future larger-scale multicenter studies are required for a full validation. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Leiner in this issue.

Second-generation motion correction algorithm improves diagnostic accuracy of single-beat coronary CT angiography in patients with increased heart rate.

OBJECTIVE: To assess the effect of a second-generation motion correction algorithm on the diagnostic accuracy of coronary computed tomography angiography (CCTA) using a 256-detector row CT in patients with increased heart rates. METHODS: Eighty-one consecutive symptomatic cardiac patients with increased heart rates (≥ 75 beats per min) were enrolled. All patients underwent CCTA and invasive coronary angiography (ICA). CCTA was performed with a 256-detector row CT using prospectively ECG-triggered single-beat protocol. Images were reconstructed using standard (STD) algorithm, first-generation intra-cycle motion correction (MC1) algorithm, and second-generation intra-cycle motion correction (MC2) algorithm. The image quality of coronary artery segments was assessed by two experienced radiologists using a 4-point scale (1: non-diagnostic and 4: excellent), according to the 18-segment model. Diagnostic performance for segments with significant lumen stenosis (≥ 50%) was compared between STD, MC1, and MC2 by using ICA as the reference standard. RESULTS: The mean effective dose of CCTA was 1.0 mSv. On per-segment level, the overall image quality score and interpretability were improved to 3.56 ± 0.63 and 99.2% due to the use of MC2, as compared to 2.81 ± 0.85 and 92.5% with STD and 3.21 ± 0.79 and 97.2% with MC1. On per-segment level, compared to STD and MC1, MC2 improved the sensitivity (92.2% vs. 79.2%, 80.7%), specificity (97.8% vs. 82.1%, 90.8%), positive predictive value (89.9% vs. 48.4%, 65.1%), negative predictive value (98.3% vs. 94.9%, 95.7%), and diagnostic accuracy (96.8% vs. 81.5%, 89.0%). CONCLUSION: A second-generation intra-cycle motion correction algorithm for single-beat CCTA significantly improves image quality and diagnostic accuracy in patients with increased heart rate. KEY POINTS: • A second-generation motion correction (MC2) algorithm can further improve the image quality of all coronary arteries than a first-generation motion correction (MC1). • MC2 algorithm can significantly reduce the number of false positive segments compared to standard and MC1 algorithm.

Additive value of 3T cardiovascular magnetic resonance coronary angiography for detecting coronary artery disease.

BACKGROUND: The purpose of the work was to evaluate the incremental diagnostic value of free-breathing, contrast-enhanced, whole-heart, 3 T cardiovascular magnetic resonance coronary angiography (CE-MRCA) to stress/rest myocardial perfusion imaging (MPI) and late gadolinium enhancement (LGE) imaging for detecting coronary artery disease (CAD). METHODS: Fifty-one patients with suspected CAD underwent a comprehensive cardiovascular magnetic resonance (CMR) examination (CE-MRCA, MPI, and LGE). The additive diagnostic value of MRCA to MPI and LGE was evaluated using invasive x-ray coronary angiography (XA) as the standard for defining functionally significant CAD (≥ 50% stenosis in vessels > 2 mm in diameter). RESULTS: 90.2% (46/51) patients (54.0 ± 11.5 years; 71.7% men) completed CE-MRCA successfully. On per-patient basis, compared to MPI/LGE alone or MPI alone, the addition of MRCA resulted in higher sensitivity (100% vs. 76.5%, p < 0.01), no change in specificity (58.3% vs. 66.7%, p = 0.6), and higher accuracy (89.1% vs 73.9%, p < 0.01) for CAD detection (prevalence = 73.9%). Compared to LGE alone, the addition of CE-MRCA resulted in higher sensitivity (97.1% vs. 41.2%, p < 0.01), inferior specificity (83.3% vs. 91.7%, p = 0.02), and higher diagnostic accuracy (93.5% vs. 54.3%, p < 0.01). CONCLUSION: The inclusion of successful free-breathing, whole-heart, 3 T CE-MRCA significantly improved the sensitivity and diagnostic accuracy as compared to MPI and LGE alone for CAD detection.

A Preliminary Study of Computed Tomography Coronary Angiography Within a Single Cardiac Cycle in Patients With Atrial Fibrillation Using 256-Row Detector Computed Tomography.

OBJECTIVE: The purpose of this study was to evaluate the image quality and radiation dose of computed tomography (CT) coronary angiography using a 256-row detector CT scanner in a single cardiac cycle in patients with atrial fibrillation (AF). METHODS: Seventy consecutive patients (41 men and 29 women; age range was from 37 to 84 years, mean age was 61.7 ± 10.2 years; body mass index range was from 15.08 to 36.45 kg/m, mean body mass index was 25.9 ± 3.5 kg/m) with persistent or paroxysmal AF during acquisition, who were not receiving any medications for heart rate (HR) regulation, were imaged with a 256-row detector CT scanner (Revolution CT, GE healthcare). According to the HR or HR variability (HRV) the patients were divided into 4 groups: group A (HR, ≥75 bpm; n = 36), group B (HR, <75 bpm; n = 34), group C (HRV, ≥50 bpm; n = 26), and group D (HRV, <50 bpm; n = 44). The snapshot freeze algorithm reconstruction was used to reduce motion artifacts whenever necessary. Two experienced radiologists, who were blinded to the electrocardiograph and reconstruction information, independently graded the CT images in terms of visibility and artifacts with a 4-grade rating scale (1, excellent; 2, good; 3, poor; 4, insufficient) using the 18-segment model. Subjective image quality scores and effective dose (ED) were calculated and compared between these groups. RESULTS: The HR during acquisition ranged from 47 to 222 bpm (88.24 ± 36.80 bpm). A total of 917 in 936 coronary artery segments were rated as diagnostically evaluable (98.2 ± 0.04%). There was no significant linear correlation between mean image quality and HR or HRV (P > 0.05). Snapshot freeze reconstruction technique was applied in 28 patients to reduce motion artifacts and thus showed image quality was improved from 93.2% to 98.4%. The ED was 3.05 ± 2.23 mSv (0.49-11.86 mSv) for all patients, and 3.76 ± 2.22 mSv (0.92-11.17 mSv), 2.30 ± 2.02 mSv (0.49-11.86 mSv), 3.89 ± 2.35 mSv (1.18-11.86 mSv), and 2.56 ± 2.03 mSv (0.49-11.17 mSv) for groups A, B, C, and D, respectively. There were significant differences in mean ED between groups A and B, as well as C and D (P <0.05). CONCLUSIONS: This study shows that CT coronary angiography with use of a new 256-row detector CT in single cardiac cycle achieves diagnostic image quality but with lower radiation dose in patients with AF. Heart rate or HRV has no significant effect on image quality.

Impact of SSF on Diagnostic Performance of Coronary Computed Tomography Angiography Within 1 Heart Beat in Patients With High Heart Rate Using a 256-Row Detector Computed Tomography.

OBJECTIVE: The aim of this study was to investigate the impact of a motion-correction algorithm on diagnostic accuracy of coronary computed tomography angiography (CCTA) within 1 heart beat in patients with high heart rate (HR) using a 256-row detector CT. METHOD: Sixty-four consecutive patients with known or suspected coronary artery disease (symptomatic) and with HR of 75 beats per minute or greater (mean [SD] HR, 82.6 [7.3] beats per minute) undergoing CCTA and invasive coronary angiography within 4 weeks were prospectively enrolled. Coronary computed tomography angiography was performed with a 256-row detector CT (Revolution CT, GE Healthcare) using prospectively electrocardiography-triggered volume scan in 1 heart beat. All images were reconstructed using standard (STD) algorithm and a motion-correction algorithm reconstruction (Snapshot Freeze SSF; GE Healthcare) technique. The image quality of coronary artery segments was evaluated by 2 experienced radiologists using a 4-point scale based on the 18-segment model. Diagnostic accuracy was compared between STD and SSF for significant lumen stenosis (≥50%) of each segment with invasive coronary angiography as the reference standard for determining significant stenosis. RESULTS: The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value with STD and SSF were 93.7%, 85.1%, 50.2%, and 98.8% versus 91.9%, 95.8%, 77.9%, and 98.7% on per-segment assessment; 98.7%, 74.0%, 62.9%, and 99.2% versus 96.2%, 94.4%, 77.9%, and 98.7% on per-artery assessment; and 100%, 14.3%, 70.5%, and 100% versus 100%, 85.7%, 93.5%, and 100% on per-patient assessment, respectively. There was a significant difference in accuracy between STD and SFF on per-patient level 71.9% versus 95.3%, on per-artery level 81.6% versus 94.9%, and per-segment level 86.3% versus 95.3%, respectively. The area under receiver operating characteristics curve analysis also showed a significant improvement on diagnostic performance with the SSF technique versus with the STD algorithm on per-patient level (P < 0.001), with corresponding area under the curve being 0.91 (95% confidence interval, 0.79-1.00) and 0.60 (95% confidence interval, 0.44-0.75). The mean effective dose was 2.0 mSv. CONCLUSIONS: Coronary computed tomography angiography can be performed in patients with high HR within 1 heart beat yielding low radiation dose. The use of SSF technique reconstruction for 1 heart beat CCTA achieves significant improvements in image quality and diagnostic value.

Early Detection of Postoperative Acute Kidney Injury in Acute Stanford Type A Aortic Dissection With Doppler Renal Resistive Index.

OBJECTIVES: This study aimed to evaluate the early efficiency of Doppler renal resistive index (DRRI) in prediction of acute kidney injury (AKI) after surgery in acute Stanford Type A aortic dissection (AAAD) patients. METHODS: Sixty-one AAAD patients who planned to receive Sun's surgical management were prospectively enrolled. The DRRI was measured by ultrasonography Doppler on the day before surgery (DRRIpre ), on admission to the intensive care unit (DRRIT0 ), 6 hours after surgery (DRRIT6 ), 24 hours after surgery (DRRIT24 ), and 48 hours after surgery (DRRIT48 ). The maximum DRRI value (DRRImax ) was recorded. The AKI was evaluated according to the classifications of the Acute Kidney Injury Network. The DRRI and serum creatinine (sCr) were compared between the pre- and postoperative time stations, as well as between the AKI and no-AKI groups. RESULTS: Thirty-nine (63.9%) patients suffered from AKI, and 12 (19.6%) patients received dialysis. No significant difference was found in DRRIpre (0.63 ± 0.04 versus 0.65 ± 0.06, P = .059) and sCrpre (84.13 ± 23.77 versus 94.29 ± 51.11, P = .383) between the two groups with and without AKI. Both the DRRI and sCr increased significantly after surgery in the AKI groups (P < .001). However, the DRRI reached its maximum 6 hours after surgery, whereas the sCr reached its maximum after 24 hours. Both the DRRI and sCr improved 48 hours after surgery. The area under the receiver operating characteristic curve for DRRImax (0.864, 95% confidence interval: 0.770-0.957) and DRRIT6 (0.861, 95% confidence interval: 0.766-0.957) was larger than the other three DRRIs measured at different time points. The cutoff value of DRRImax was 0.71, a sensitivity of 76.9% and specificity of 95.5%. CONCLUSIONS: Postoperative DRRI predicts the AKI earlier than sCr after AAAD surgery. The best time to detect DRRI was 6 hours after surgery.

Diagnostic Performance of Self-navigated Whole-Heart Contrast-enhanced Coronary 3-T MR Angiography.

Purpose To evaluate the diagnostic performance of self-navigated whole-heart coronary 3-T magnetic resonance (MR) angiography by using conventional invasive coronary angiography (ICA) as the reference gold standard. Materials and Methods This study was approved by the local ethics committee. Written informed consent was obtained from each patient before the study. Thirty-nine consecutive patients underwent coronary MR angiography and later underwent ICA. Coronary MR angiography was performed with a 3-T imager with contrast agent enhancement during free breathing with self-navigated affine motion correction reconstruction. Coronary segments with reference diameters larger than 1.5 mm were included in the comparison between coronary MR angiography and ICA. The coronary MR angiography images were evaluated by two experienced readers blinded to the ICA results to identify significant luminal narrowing (>50% diameter reduction in reference ICA). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were performed to detect significant coronary artery stenosis. Results Coronary MR angiography examinations were successfully performed in all 39 patients. A total of 327 coronary segments had reference luminal diameter larger than 1.5 mm. Of these 327 coronary segments, 303 (92.7%) segments had a quality score greater than 1 at coronary MR angiography and were included in the analysis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 78.2%, 75.0%, 81.8%, 70.6%, and 76.9%, respectively, on a per-patient basis. Conclusion Contrast-enhanced self-navigated coronary 3-T MR angiography is a promising technique for the noninvasive detection of clinically significant coronary stenosis. © RSNA, 2016.

External Magnetic Field-Induced Targeted Delivery of Highly Sensitive Iron Oxide Nanocubes for MRI of Myocardial Infarction.

Magnetic field responsive nanocubes (MFRFs) are synthesized as nanoplatforms for external magnetic field-induced selective targeting of macrophages in the infarcted tissue and magnetic resonance imaging (MRI) monitoring. MFRFs have uniform size, favorable colloidal stability, and high magnetic properties. Under the influence of external magnetic field, MFRFs perform qualitative and quantitative MRI of myocardial infarction.

Histological validation of cardiac magnetic resonance T1 mapping for detecting diffuse myocardial fibrosis in diabetic rabbits.

PURPOSE: To pathologically verify the correlation between native T1 mapping, postcontrast T1 mapping, and extracellular volume fraction (ECV) and myocardial diffuse fibrosis, as determined by collagen volume fraction (CVF). MATERIALS AND METHODS: Thirty New Zealand white rabbits were randomly divided into the control group (n = 6), diabetes 3 months group (n = 8), diabetes 6 months group (n = 8), and diabetes 9 months group (n = 8). All the rabbits underwent clinical 3.0T magnetic resonance (MR) examinations with pre- and postcontrast modified Look-Locker inversion recovery T1 mapping. For the histological study, each rabbit was sacrificed after MR scanning, hematoxylin and eosin and Masson staining of the left ventricular myocardium were performed, and CVF was calculated. Pre- and postcontrast T1 values and ECV were compared to CVF using Pearson's correlation coefficients. RESULTS: Two rabbits died in each diabetes group, thus each group included six rabbits. ECV calculated from pre- and postcontrast T1 values showed a very strong correlation with CVF (r = 0.876, P < 0.001), whereas postcontrast T1 values exhibited a moderate correlation with CVF (r = -0.564, P = 0.004). In contrast, precontrast T1 values showed no correlation with CVF (r = 0.311, P = 0.139). CONCLUSION: ECV has a very strong correlation with pathological CVF, and can be used to assess the degree of diffuse myocardial fibrosis better than the postcontrast T1 value. Precontrast T1 value has no significant correlation with diffuse myocardial fibrosis. J. Magn. Reson. Imaging 2016;44:1179-1185.

DANTE-prepared three-dimensional FLASH: A fast isotropic-resolution MR approach to morphological evaluation of the peripheral arterial wall at 3 Tesla.

BACKGROUND: To develop and assess a sequence using DANTE dark-blood preparation combined with FLASH readout (DANTE-FLASH) for rapid isotropic-resolution three-dimensional (3D) peripheral vessel wall imaging at 3 Tesla (T). METHODS: Numerical simulations were first conducted to optimize imaging parameters for maximizing the wall-lumen contrast. The sequence, implemented at 3T, was then assessed in the bilateral superficial femoral arteries of eight healthy volunteers and three patients who were undergoing non-contrast-enhanced MRA due to known peripheral artery disease. Conventional 2D dark-blood turbo spin echo (DB-TSE) was performed as a reference in all subjects. Image quality on a 5-point scale, apparent wall signal-to-noise ratio, apparent wall-lumen contrast-to-noise ratio, wall thickness, wall area and lumen area were assessed or measured in all healthy subjects. Additionally, the agreement in the depiction of wall thickening or luminal stenosis between DANTE-FLASH and DB-TSE, or MRA was assessed using a 4-point scale in the patient study. RESULTS: DANTE-FLASH allowed for a 30-cm-long coverage within 4 min, whereas DB-TSE took approximately 7 min for a 9-cm-long coverage. Good image quality was obtained by DANTE-FLASH (score > 3). The wall thickness, wall area, and lumen area were all comparable (t-test; P = 0.334, 0.224 and 0.136) and showed excellent agreement between DANTE-FLASH and DB-TSE (intra-class correlation = 0.81, 0.85, and 0.98). The atherosclerotic plaques and luminal stenosis identified by DANTE-FLASH were in accordance with the findings by 2D DB-TSE or MRA. CONCLUSION: DANTE-FLASH is a 3D dark-blood MR sequence allowing for rapid isotropic-resolution imaging of the peripheral vessel wall at 3T.

Noncontrast MR angiography (MRA) of infragenual arteries using flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP) at 3.0 Tesla: Comparison with contrast-enhanced MRA.

BACKGROUND: To evaluate the feasibility and diagnostic performance of flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP) MR angiography (MRA) for imaging infragenual arteries at 3.0T, with contrast enhanced MR angiography (CE MRA) as reference. METHODS: Twenty consecutive patients with suspicion of lower extremity arterial disease undergoing routine CE MRA were recruited. FSD MRA was performed at calf before CE MRA. Image quality and stenosis degree of infragenual arteries from both techniques were independently evaluated and compared. Six patients in this study underwent DSA examination. RESULTS: Three undiagnostic segments were excluded with severe venous contamination in CE MRA. A total of 197 calf arterial segments images were analyzed. No significant difference existed in the relative signal intensity (rSI) of arterial segments between FSD MRA and CE MRA techniques (0.92 ± 0.09 versus 0.93 ± 0.05; P = 0.207). However, the subjective image quality score was slightly higher in FSD MRA (3.66 ± 0.81 versus 3.49 ± 0.87; P = 0.050). With CE MRA images as reference standard, slight overestimation existed in FSD MRA (2.19 ± 1.24 versus 2.09 ± 1.18; P = 0.019), with total agreement of 84.3% on the basis of all arterial segments. The sensitivity, specificity, negative predictive value, and positive predictive value of FSD MRA was 96.4%, 93.0%, 98.5%, and 84.1%. No significant difference in the stenosis degree score was detected between MRA (FSD MRA and CE MRA) and DSA (P > 0.05). CONCLUSION: FSD MRA performed on at 3.0T without the use of contrast medium provides diagnostic images allowing for arterial stenosis assessment of calf arteries that was highly comparable with CE MRA. Moreover, venous contamination was less problematic with FSD MRA.

Systolic MOLLI T1 mapping with heart-rate-dependent pulse sequence sampling scheme is feasible in patients with atrial fibrillation.

BACKGROUND: T1 mapping enables assessment of myocardial characteristics. As the most common type of arrhythmia, atrial fibrillation (AF) is often accompanied by a variety of cardiac pathologies, whereby the irregular and usually rapid ventricle rate of AF may cause inaccurate T1 estimation due to mis-triggering and inadequate magnetization recovery. We hypothesized that systolic T1 mapping with a heart-rate-dependent (HRD) pulse sequence scheme may overcome this issue. METHODS: 30 patients with AF and 13 healthy volunteers were enrolled and underwent cardiovascular magnetic resonance (CMR) at 3 T. CMR was repeated for 3 patients after electric cardioversion and for 2 volunteers after lowering heart rate (HR). A Modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired before and 15 min after administration of 0.1 mmol/kg gadopentetate dimeglumine. For AF patients, both the fixed 5(3)3/4(1)3(1)2 and the HRD sampling scheme were performed at diastole and systole, respectively. The HRD pulse sequence sampling scheme was 5(n)3/4(n)3(n)2, where n was determined by the heart rate to ensure adequate magnetization recovery. Image quality of T1 maps was assessed. T1 times were measured in myocardium and blood. Extracellular volume fraction (ECV) was calculated. RESULTS: In volunteers with repeated T1 mapping, the myocardial native T1 and ECV generated from the 1st fixed sampling scheme were smaller than from the 1st HRD and 2nd fixed sampling scheme. In healthy volunteers, the overall native T1 times and ECV of the left ventricle (LV) in diastolic T1 maps were greater than in systolic T1 maps (P < 0.01, P < 0.05). In the 3 AF patients that had received electrical cardioversion therapy, the myocardial native T1 times and ECV generated from the fixed sampling scheme were smaller than in the 1st and 2nd HRD sampling scheme (all P < 0.05). In patients with AF (HR: 88 ± 20 bpm, HR fluctuation: 12 ± 9 bpm), more T1 maps with artifact were found in diastole than in systole (P < 0.01). The overall native T1 times and ECV of the left ventricle (LV) in diastolic T1 maps were greater than systolic T1 maps, either with fixed or HRD sampling scheme (all P < 0.05). CONCLUSION: Systolic MOLLI T1 mapping with heart-rate-dependent pulse sequence scheme can improve image quality and avoid T1 underestimation. It is feasible and with further validation may extend clinical applicability of T1 mapping to patients with atrial fibrillation.

Diagnostic performance of computed tomography for detection of concomitant coronary disease in hypertrophic cardiomyopathy.

OBJECTIVES: To evaluate the diagnostic performance of computed tomography (CT) in patients with hypertrophic cardiomyopathy (HCM) and suspected coexistent coronary artery diseases (CADs). METHODS: Sixty patients were enrolled in this study. Cardiac CT examination included CT coronary angiography (CTCA) and delayed enhancement CT. CT performance in evaluation of the coronary artery was assessed and compared with that of catheter-based coronary angiography (CA). The left ventricle (LV) wall thickness, functional indices and myocardial delayed enhancement (MDE) were measured via cardiac magnetic resonance (CMR) and CT images. RESULTS: Compared with catheter-based CA, CTCA produced a 100 % (24/24) sensitivity, a 94.4 % (34/36) specificity, a 92.3 % (24/26) positive predictive value and a 100 % (34/34) negative predictive value. CT-measured LV wall thickness and functional indices were correlated with those measured via CMR (P < 0.01), though the CT-measured values were smaller than the CMR-measured values. Bland-Altman analysis showed the volume of the focal MDE determined via CT was slightly smaller than that determined using CMR (mean difference: 0.3 cm(3)). CONCLUSIONS: For patients with HCM and suspected coexistent CAD, this comprehensive cardiac CT protocol can be helpful in ruling out coronary stenosis and can provide information regarding morphology, function and tissue characterization of the LV myocardium.

Coronary computed tomographic angiography in coronary artery bypass grafts: comparison between low-concentration Iodixanol 270 and Iohexol 350.

OBJECTIVE: The aim of this study was to evaluate the feasibility of low-concentration iso-osmolar Iodixanol 270 compared with Iohexol 350 in patients with coronary artery bypass grafts (CABGs) undergoing coronary computed tomographic angiography (CCTA). METHODS: A total of 80 consecutive patients undergoing CABG follow-up with the use of CCTA were prospectively enrolled, with 40 patients assigned to Iodixanol 270 and 40 patients assigned to Iohexol 350. In both groups, the contrast medium was injected at an injection rate of 4.5 mL/s in the patients with a body mass index of greater than 24 kg/m2 and 3.5 mL/s in the patients with a body mass index of 24 kg/m2 or lower. The contrast volume was determined by the flow rate and scan time. Image quality score and visualization of bypass grafts were evaluated. Subjective assessment of image quality for each coronary artery segment was determined using a 4-point grading scale by 2 reviewers, whereas objective evaluation of image quality was conducted by measuring the mean CT attenuation values (hounsfield unit [HU]) in terms of SD, contrast-noise ratio, and signal-noise ratio in the ascending aorta. RESULTS: The mean (SD) contrast volume for the Iodixanol 270 and Iohexol 350 groups was 66.28 (12.00) and 64.98 (8.12) mL, respectively, with no significant difference (P = 0.57). The mean (SD) CT attenuation value in the Iodixanol 270 group was 414.72 (101.47), which was lower than in the Iohexol 350 group, which was 478.85 (108.73) (P = 0.01). The subjective image quality for the Iodixanol 270 group was superior to that for the Iohexol 350 group in the arterial graft vessels (P = 0.027), whereas there was no significant difference between the 2 groups in the venous graft vessels (P = 0.377). There was no significant difference in terms of SD of the ascending aorta, signal-noise ratio, and contrast-noise ratio between the 2 groups. CONCLUSIONS: Low-concentration iso-osmolar Iodixanol 270 provides image quality comparable with that of Iohexol 350, allowing diagnostic CCTA follow-up of patients with CABGs.

CT characteristics of dehiscent sigmoid plates presenting as pulsatile tinnitus: a study of 23 patients.

BACKGROUND: Although some features of dehiscent sigmoid plates as a cause of pulsatile tinnitus (PT) have been reported, detailed imaging findings have not been evaluated. PURPOSE: To retrospectively evaluate the computed tomography (CT) features of dehiscent sigmoid plates associated with PT. MATERIAL AND METHODS: The CT images of 23 PT patients were assessed to evaluate the features of the dehiscent sigmoid plates, lateral sinuses, and temporal bone pneumatization. RESULTS: A total of 31 defects were found on the PT side. Twenty-five defects involved the superior curve or the descending segment, four involved above both sites, and only two involved the inferior curve. Twenty-six defects involved the anterior border or the anterolateral border, and only five involved the lateral border of the sigmoid sinus. The dehiscent sigmoid plate was on the dominant side in all 18 patients with a unilateral dominant lateral sinus, and on the right side in two patients and on the left side in three patients with co-dominant lateral sinuses. Fourteen patients had hyperpneumatization and nine had good pneumatization of temporal bone. Fifteen of the 17 patients with resolution of PT after surgery had a single defect. Four of the six patients with persistence of PT after surgery had more than one defect. CONCLUSION: Sigmoid plate dehiscence often involves the anterior or anterolateral border of the superior curve or the descending segment of the sigmoid sinus on the side of the dominant lateral sinus, which often coexists with extensive pneumatization of the temporal bone.

[Assessment of congenital vascular rings with MDCT on children].

OBJECTIVE: To evaluate the value of MDCT on diagnosis of congenital vascular rings on children. METHODS: Retrospective analysis on 43 cases of congenital vascular rings, which underwent MDCT during Oct 2008 to Dec 2014 in Beijing Anzhen hospital affiliated to capital medical university. 21 males, 22 females; age from 29 days to 8 years, mean age 1.46 years, 33 cases are not beyond 1 year. All the results were compared with that of the echocardiogram or record of the surgery. The CT data were read and reconstructed with multiplanar reconstruction (MPR), maximum intensity projection (MPR), minimum intensity projection (MinIP), volume rendering (VR). The image quality was evaluated and the diagnostic value and the standard diagnostic program were discussed. RESULTS: Of 43 cases of vascular rings:there were 6 cases of pulmonary artery sling (13.95%), 9 cases of right aortic arch /aberrant left subclavian artery(20.93%), 18 cases of left aortic arch/aberrant right subclavian artery (41.86%), 10 cases of double aortic arch (23.26%). Forty cases (93.02%) were combined with other cardiovascular or pulmonary malformations. Every malformation was revealed clearly and proved by echocardiogram. Of 3 cases (6.98%) without any other malformation, 2 cases were combined tracheal stenosis. A pulmonary artery sling was proved by surgery; the other 2 cases were double aortic arch. All the images of 43 cases could be reconstructed well. MPR and VR showed the origin, shape, and whole course of vascular rings directly; MinIP and VR could display the shape, width and development of trachea, revealed the relationship between vascular rings, trachea and esophagus. It was important to show and measure the component vascular of the ring. Attention should be paid to the whole course of trachea and esophagus, especially those segments which were close to the ring vascular. The tracheal stenosis as well as intra-cardio anatomy malformations should be measured on MPR images if existed. According to the segmental analysis method, comes the overall final diagnosis. A standard diagnostic program on vascular ring was proposed. CONCLUSION: MDCT axis images with various 3D post processing methods could reveal the compose of vascular rings and the relationship between vascular rings, trachea and esophagus.

A novel approach for hybrid repair of type B aortic dissection associated with coarctation of the aorta.

We report the case of an acute type B aortic dissection in association with an unknown isthmic coarctation in a 53-year-old man. An intimal tear was located just distal to the coarctation, and the intimal flap extended to the level of the renal arteries. Hybrid repair was performed successfully 4 months later, without deep hypothermic circulatory arrest. An extra-anatomic bypass connected the ascending aorta to the abdominal aorta. The coarctation was occluded using a ventricular septal defect occluder. The hybrid repair was safe and effective for the patient.