The impact of water exchange on estimates of myocardial extracellular volume calculated using contrast enhanced T1 measurements: A preliminary analysis in patients with severe aortic stenosis.

PURPOSE: Guidelines recommend measuring myocardial extracellular volume (ECV) using T1 -mapping before and 10-30 min after contrast agent administration. Data are then analyzed using a linear model (LM), which assumes fast water exchange (WX) between the ECV and cardiomyocytes. We investigated whether limited WX influences ECV measurements in patients with severe aortic stenosis (AS). METHODS: Twenty-five patients with severe AS and 5 healthy controls were recruited. T1 measurements were made on a 3 T Siemens system using a multiparametric saturation-recovery single-shot acquisition (a) before contrast; (b) 4 min post 0.05 mmol/kg gadobutrol; and (c) 4 min, (d) 10 min, and (e) 30 min after an additional gadobutrol dose (0.1 mmol/kg). Three LM-based ECV estimates, made using paired T1 measurements (a and b), (a and d), and (a and e), were compared to ECV estimates made using all 5 T1 measurements and a two-site exchange model (2SXM) accounting for WX. RESULTS: Median (range) ECV estimated using the 2SXM model was 25% (21%-39%) for patients and 26% (22%-29%) for controls. ECV estimated in patients using the LM at 10 min following a cumulative contrast dose of 0.15 mmol/kg was 21% (17%-32%) and increased significantly to 22% (19%-35%) at 30 min (p = 0.0001). ECV estimated using the LM was highest following low dose gadobutrol, 25% (19%-38%). CONCLUSION: Current guidelines on contrast agent dose for ECV measurements may lead to underestimated ECV in patients with severe AS because of limited WX. Use of a lower contrast agent dose may mitigate this effect.

Update on muscle imaging in myositis.

PURPOSE OF REVIEW: Imaging techniques such as MRI, ultrasound and PET/computed tomography (CT) have roles in the detection, diagnosis and management of myositis or idiopathic inflammatory myopathy (IIM). Imaging research has also provided valuable knowledge in the understanding of the pathology of IIM. This review explores the latest advancements of these imaging modalities in IIM. RECENT FINDINGS: Recent advancements in imaging of IIM have seen a shift away from manual and qualitative analysis of the images. Quantitative MRI provides more objective, and potentially more sensitive characterization of fat infiltration and inflammation in muscles. In addition to B-mode ultrasound changes, shearwave elastography offers a new dimension to investigating IIM. PET/CT has the added advantage of including IIM-associated findings such as malignancies. SUMMARY: It is evident that MRI, ultrasound and PET/CT have important roles in myositis. Continued technological advancement and a quest for more sophisticated applications help drive innovation; this has especially been so of machine learning/deep learning using artificial intelligence and the developing promise of texture analysis.

First pilot study of extracellular volume MRI measurement in peripheral muscle of systemic sclerosis patients suggests diffuse fibrosis.

OBJECTIVES: Peripheral muscle involvement in SSc may comprise myositis or a non-inflammatory myopathy. There is little understanding of the nature of SSc myopathy. This pilot study aimed to evaluate the presence of diffuse fibrosis in the peripheral muscle of patients with SSc by determining extracellular volume (ECV) MRI measurement. METHODS: SSc patients, with either suspected myopathy or no muscle involvement, and healthy controls (HCs) had native T1 and ECV MRI quantification of the thigh and creatine-kinase (CK) measured. Suspected myopathy was defined as current / history of minimally raised CK (>320; <600 IU/l) ± presence of clinical signs/symptoms (including proximal lower-limb muscle weakness and/or myalgia) ± a Manual Muscle Testing (MMT) 8 score of <5 in the thighs. RESULTS: Twelve SSc patients and 10 HCs were recruited. Of the 12 patients, 9 had limited cutaneous SSc, 4 had interstitial lung disease, and 7 had suspected myopathy. The higher skeletal muscle ECV was recorded for SSc patients compared with HCs [mean (s.d.) 23 (11)%, vs 11 (4)%, P = 0.04]. Peripheral muscle ECV was associated with CK (rho = 0.554, P = 0.061) and was higher in SSc patients with myopathy than in those with no myopathy [mean (s.d.) 28 (10) vs 15 (5), P = 0.023]. It was determined that an ECV of 22% best identified myopathy (with a sensitivity of 71% and a specificity of 80%). CONCLUSION: This hypothesis-generating study showed higher ECV in SSc patients compared with HCs, as well as association of ECV with suspected myopathy, suggesting the presence of diffuse fibrosis in the peripheral muscle of SSc patients. Further studies are needed to understand the nature of SSc myopathy.

Muscle deterioration due to rheumatoid arthritis: assessment by quantitative MRI and strength testing.

OBJECTIVES: RA patients often present with low muscle mass and decreased strength. Quantitative MRI offers a non-invasive measurement of muscle status. This study assessed whether MRI-based measurements of T2, fat fraction, diffusion tensor imaging and muscle volume can detect differences between the thigh muscles of RA patients and healthy controls, and assessed the muscle phenotype of different disease stages. METHODS: Thirty-nine RA patients (13 'new RA'-newly diagnosed, treatment naïve, 13 'active RA'-persistent DAS28 >3.2 for >1 year, 13 'remission RA'-persistent DAS28 <2.6 for >1 year) and 13 age and gender directly matched healthy controls had an MRI scan of their dominant thigh. All participants had knee extension and flexion torque and grip strength measured. RESULTS: MRI T2 and fat fraction were higher in the three groups of RA patients compared with healthy controls in the thigh muscles. There were no clinically meaningful differences in the mean diffusivity. The muscle volume, handgrip strength, knee extension and flexion were lower in all three groups of RA patients compared with healthy controls. CONCLUSION: Quantitative MRI and muscle strength measurements can potentially detect differences within the muscles between RA patients and healthy controls. These differences may be seen in RA patients who are yet to start treatment, those with persistent active disease, and those who were in clinical remission. This suggests that the muscles in RA patients are affected in the early stages of the disease and that signs of muscle pathology and muscle weakness are still observed in clinical remission.

Predictors of subclinical systemic sclerosis primary heart involvement characterised by microvasculopathy and myocardial fibrosis.

OBJECTIVES: SSc primary heart involvement (SSc-pHI) is a significant cause of mortality. We aimed to characterize and identify predictors of subclinical SSc-pHI using cardiovascular MRI. METHODS: A total of 83 SSc patients with no history of cardiovascular disease or pulmonary arterial hypertension and 44 healthy controls (HCs) underwent 3 Tesla contrast-enhanced cardiovascular MRI, including T1 mapping and quantitative stress perfusion. High-sensitivity troponin I and N-terminal pro-brain natriuretic peptide were also measured. RESULTS: Cardiovascular MRI revealed a lower myocardial perfusion reserve in the SSc patients compared with HCs {median (interquartile range (IQR)] 1.9 (1.6-2.4) vs 3 (2-3.6), P < 0.001}. Late gadolinium enhancement, indicating focal fibrosis, was observed in 17/83 patients but in none of the HCs, with significantly higher extracellular volume (ECV), suggestive of diffuse fibrosis, in SSc vs HC [mean (s.d.) 31 (4) vs 25 (2), P < 0.001]. Presence of late gadolinium enhancement and higher ECV was associated with skin score [odds ratio (OR) = 1.115, P = 0.048; R2 = 0.353, P = 0.004], and ECV and myocardial perfusion reserve was associated with the presence of digital ulcers at multivariate analysis (R2 = 0.353, P < 0.001; R2 = 0.238, P = 0.011). High-sensitivity troponin I was significantly higher in patients with late gadolinium enhancement, and N-terminal pro-brain natriuretic peptide was associated with ECV (P < 0.05). CONCLUSION: Subclinical SSc-pHI is characterized by myocardial microvasculopathy, diffuse and focal myocardial fibrosis but preserved myocardial contractile function. This subclinical phenotype of SSc-pHI was associated with high-sensitivity troponin I, N-terminal pro-brain natriuretic peptide, SSc disease severity and complicated peripheral vasculopathy. These data provide information regarding the underlying pathophysiological processes and provide a basis for identifying individuals at risk of SSc-pHI.

A randomized, open-label, active comparator trial assessing the effects of 26 weeks of liraglutide or sitagliptin on cardiovascular function in young obese adults with type 2 diabetes.

AIM: To compare the effects of a glucagon-like peptide-1 receptor agonist and a dipeptidyl peptidase-4 inhibitor on magnetic resonance imaging-derived measures of cardiovascular function. MATERIALS AND METHODS: In a prospective, randomized, open-label, blinded endpoint trial liraglutide (1.8 mg) and sitagliptin (100 mg) were compared in asymptomatic, non-insulin treated young (aged 18-50 years) adults with obesity and type 2 diabetes. The primary outcome was difference in circumferential peak early diastolic strain rate change (PEDSR), a biomarker of cardiac diastolic dysfunction 26 weeks after randomization. Secondary outcomes included other indices of cardiac structure and function, HbA1c and body weight. RESULTS: Seventy-six participants were randomized (54% female, mean ± SD age 44 ± 6 years, diabetes duration 4.4 years, body mass index 35.3 ± 6.1 kg m-2 ), of whom 65% had ≥1 cardiovascular risk factor. Sixty-one participants had primary outcome data available. There were no statistically significant between-group differences (intention-to-treat; mean [95% confidence interval]) in PEDSR change (-0.01 [-0.07, +0.06] s-1 ), left ventricular ejection fraction (-1.98 [-4.90, +0.94]%), left ventricular mass (+1.14 [-5.23, +7.50] g) or aortic distensibility (-0.35 [-0.98, +0.28] mmHg-1 × 10-3 ) after 26 weeks. Reductions in HbA1c (-4.57 [-9.10, -0.37] mmol mol-1 ) and body weight (-3.88 [-5.74, -2.01] kg) were greater with liraglutide. CONCLUSION: There were no differences in cardiovascular structure or function after short-term use of liraglutide and sitagliptin in younger adults with obesity and type 2 diabetes. Longer studies in patients with more severe cardiac dysfunction may be necessary before definitive conclusions can be made about putative pleiotropic properties of incretin-based therapies.

Incidental significant arrhythmia in scleroderma associates with cardiac magnetic resonance measure of fibrosis and hs-TnI and NT-proBNP.

OBJECTIVES: To screen for significant arrhythmias with an implantable loop recorder (ILR) in patients with SSc and no known cardiovascular disease, and identify associated disease phenotype, blood and cardiovascular magnetic resonance (CMR) biomarkers. METHODS: Twenty patients with SSc with no history of primary SSc heart disease, traditional cardiovascular disease, diabetes or maximum one traditional cardiovascular risk factor underwent clinical assessment, contrast-enhanced CMR and ILR insertion. RESULTS: ILR data were available for 19 patients: 63% female, mean (s.d.) age of 53 (12) years, 32% diffuse SSc. Eight patients had significant arrhythmias over 3 years: one complete heart block, two non-sustained ventricular tachycardia [all three dcSSc, two anti-topoisomerase antibodies (Scl70) positive, three interstitial lung disease and two previous digital ulceration] and five atrial arrhythmias of which four were with limited SSc. These required interventions with one permanent pacemaker implantation, four anti-arrhythmic pharmacotherapy, one anticoagulation.Patients with significant arrhythmia had higher baseline high-sensitivity troponin I and N-terminal pro-brain natriuretic peptide [mean difference (95% CI) 117 (-11, 245) and 92 (-30, 215) ng/l, respectively], and CMR-extracellular volume [mean (s.d.) 32 (2) vs 29 (4)%]. Late gadolinium enhancement was observed in five patients, only one with significant arrhythmia. CONCLUSION: This first ILR study identified potentially life-threatening arrhythmias in asymptomatic SSc patients attributable to a primary SSc heart disease. Disease phenotype, CMR-extracellular volume (indicating diffuse fibrosis) and cardiac biomarkers may identify at-risk patients that would benefit from ILR screening. Future studies can inform a risk model and provide insights into SSc-associated arrhythmia pathogenesis.

A comparison of cardiovascular magnetic resonance and single photon emission computed tomography (SPECT) perfusion imaging in left main stem or equivalent coronary artery disease: a CE-MARC substudy.

BACKGROUND: Assessment of left main stem (LMS) stenosis has prognostic and therapeutic implications. Data on assessment of LMS disease by cardiovascular magnetic resonance (CMR) and single photon emission computed tomography (SPECT) are limited. CE-MARC is the largest prospective comparison of CMR and SPECT against quantitative invasive coronary angiography (QCA) for detection of coronary artery disease (CAD), and provided the framework for this evaluation. The aims of this study were to compare diagnostic accuracy of visual and quantitative perfusion CMR to SPECT in patients with LMS stable CAD. METHODS: Fifty-four patients from the CE-MARC study were included: 27 (4%) with significant LMS or LMS-equivalent disease on QCA, and 27 age/sex-matched patients with no flow-limiting CAD. All patients underwent multi-parametric CMR, SPECT and QCA. Performance of visual and quantitative perfusion CMR by Fermi-constrained deconvolution to detect LMS disease was compared with SPECT. RESULTS: Of 27 patients in the LMS group, 22 (81%) had abnormal CMR and 16 (59%) had abnormal SPECT. All patients with abnormal CMR had abnormal perfusion by visual analysis. CMR demonstrated significantly higher area under the curve (AUC) for detection of disease (0.95; 0.85-0.99) over SPECT (0.63; 0.49-0.76) (p = 0.0001). Global mean stress myocardial blood flow (MBF) by CMR in LMS patients was significantly lower than controls (1.77 ± 0.72 ml/g/min vs. 3.28 ± 1.20 ml/g/min, p < 0.001). MBF of <2.08 ml/g/min had sensitivity of 78% and specificity of 85% for diagnosis of LMS disease, with an AUC (0.87; 0.75-0.94) not significantly different to visual CMR analysis (p = 0.18), and more accurate than SPECT (p = 0.003). CONCLUSION: Visual stress perfusion CMR had higher diagnostic accuracy than SPECT to detect LMS disease. Quantitative perfusion CMR had similar performance to visual CMR perfusion analysis.

Sensitivity of quantitative myocardial dynamic contrast-enhanced MRI to saturation pulse efficiency, noise and t1 measurement error: Comparison of nonlinearity correction methods.

PURPOSE: To compare methods designed to minimize or correct signal nonlinearity in quantitative myocardial dynamic contrast-enhanced (DCE) MRI. METHODS: DCE-MRI studies were simulated and data acquired in eight volunteers. Signal nonlinearity was corrected using either a dual-bolus approach or model-based correction using proton-density weighted imaging (conventional or dual-sequence acquisition) or T1 data (native or bookend). Scanning of healthy and infarcted myocardium at 3 T was simulated, including noise, saturation imperfection and T1 measurement error. Data were analyzed using model-based deconvolution with a one-compartment (mono-exponential) model. RESULTS: Substantial variation between methods was demonstrated in volunteers. In simulations the dual-bolus method proved stable for realistic levels of saturation efficiency but demonstrated bias due to residual nonlinearity. Model-based methods performed ideally in the absence of confounding error sources and were generally robust to noise or saturation imperfection, except for native T1 based correction which was highly sensitive to the latter. All methods demonstrated large variation in accuracy above an over-saturation level where baseline signal was nulled. For the dual-sequence approach this caused substantial bias at the saturation efficiencies observed in volunteers. CONCLUSION: The choice of nonlinearity correction method in myocardial DCE-MRI impacts on accuracy and precision of estimated parameters, particularly in the presence of nonideal saturation.

Comparison of the Diagnostic Performance of Four Quantitative Myocardial Perfusion Estimation Methods Used in Cardiac MR Imaging: CE-MARC Substudy.

PURPOSE: To compare the diagnostic performance of four tracer kinetic analysis methods to quantify myocardial perfusion from magnetic resonance (MR) imaging cardiac perfusion data sets in terms of their ability to lead to the diagnosis of myocardial ischemia. MATERIALS AND METHODS: The study was approved by the regional ethics committee, and all patients gave written consent. A representative sample of 50 patients with suspected ischemic heart disease was retrospectively selected from the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease trial data set. Quantitative myocardial blood flow (MBF) was estimated from rest and adenosine stress MR imaging perfusion data sets by using four established methods. A matching diagnosis of both an inducible defect as assessed with single photon emission computed tomography and a luminal stenosis of 70% or more as assessed with quantitative x-ray angiography was used as the reference standard for the presence of myocardial ischemia. Diagnostic performance was evaluated with receiver operating characteristic (ROC) curve analysis for each method, with stress MBF and myocardial perfusion reserve (MPR) serving as continuous measures. RESULTS: Area under the ROC curve with stress MBF and MPR as the outcome measures, respectively, was 0.86 and 0.92 for the Fermi model, 0.85 and 0.87 for the uptake model, 0.85 and 0.80 for the one-compartment model, and 0.87 and 0.87 for model-independent deconvolution. There was no significant difference between any of the models or between MBF and MPR, except that the Fermi model outperformed the one-compartment model if MPR was used as the outcome measure (P = .02). CONCLUSION: Diagnostic performance of quantitative myocardial perfusion estimates is not affected by the tracer kinetic analysis method used.

Cardiac MR imaging to measure myocardial blood flow response to the cold pressor test in healthy smokers and nonsmokers.

PURPOSE: To determine if myocardial perfusion cardiac magnetic resonance (MR) imaging can show changes in myocardial blood flow (MBF) during the cold pressor test (CPT) and can allow identification of the differing endothelial function of smokers and nonsmokers when compared during adenosine stress. MATERIALS AND METHODS: The study was approved by the institutional ethics review board and all participants gave informed written consent. Twenty-nine healthy volunteers (19 nonsmokers, 10 smokers; mean age ± standard deviation, 22 years ± 4) underwent 1.5-T MR imaging and analysis. Myocardial perfusion was assessed during rest, peak CPT, and adenosine hyperemia with a saturation-recovery gradient-echo pulse sequence (spatial resolution, 2.4 × 2.4 × 10 mm). Global, endocardial, and epicardial MBF were calculated by using Fermi-constrained deconvolution. Paired and independent t test statistical analyses were used to compare the responses between tests and groups. Regression analysis was performed to identify predictors of MBF change. RESULTS: MBF at rest was similar between the nonsmoking and smoking groups (0.97 mL/g/min ± 0.4 vs 0.96 mL/g/min ± 0.3, respectively; P = .96). Nonsmokers responded to CPT with a 47% increase in MBF (1.43 mL/g/min ± 0.5) and smokers responded with a 27% increase (1.22 mL/g/min ± 0.4; P < .001). An endocardial-to-epicardial gradient existed at rest (nonsmokers, 1.10 [P = .002]; smokers, 1.30 [P = .01]) and CPT (nonsmokers, 1.19 [P < .001] smokers, 1.28 [P = .04]) but reversed during adenosine stress (nonsmokers, 0.89 [P = .03]; smokers, 0.92 [P = .42]). CONCLUSION: Myocardial perfusion cardiac MR imaging during CPT can allow assessment of changes in MBF globally and in the separate myocardial layers in healthy smokers and nonsmokers. This allows the combined assessment of endothelium-dependent (CPT) and endothelium-independent (adenosine stress test) MBF reserve in a single study.

Susceptibility-weighted cardiovascular magnetic resonance in comparison to T2 and T2 star imaging for detection of intramyocardial hemorrhage following acute myocardial infarction at 3 Tesla.

BACKGROUND: Intramyocardial hemorrhage (IMH) identified by cardiovascular magnetic resonance (CMR) is an established prognostic marker following acute myocardial infarction (AMI). Detection of IMH by T2-weighted or T2 star CMR can be limited by long breath hold times and sensitivity to artefacts, especially at 3T. We compared the image quality and diagnostic ability of susceptibility-weighted magnetic resonance imaging (SW MRI) with T2-weighted and T2 star CMR to detect IMH at 3T. METHODS: Forty-nine patients (42 males; mean age 58 years, range 35-76) underwent 3T cardiovascular magnetic resonance (CMR) 2 days following re-perfused AMI. T2-weighted, T2 star and SW MRI images were obtained. Signal and contrast measurements were compared between the three methods and diagnostic accuracy of SW MRI was assessed against T2w images by 2 independent, blinded observers. Image quality was rated on a 4-point scale from 1 (unusable) to 4 (excellent). RESULTS: Of 49 patients, IMH was detected in 20 (41%) by SW MRI, 21 (43%) by T2-weighted and 17 (34%) by T2 star imaging (p = ns). Compared to T2-weighted imaging, SW MRI had sensitivity of 93% and specificity of 86%. SW MRI had similar inter-observer reliability to T2-weighted imaging (κ = 0.90 and κ = 0.88 respectively); both had higher reliability than T2 star (κ = 0.53). Breath hold times were shorter for SW MRI (4 seconds vs. 16 seconds) with improved image quality rating (3.8 ± 0.4, 3.3 ± 1.0, 2.8 ± 1.1 respectively; p < 0.01). CONCLUSIONS: SW MRI is an accurate and reproducible way to detect IMH at 3T. The technique offers considerably shorter breath hold times than T2-weighted and T2 star imaging, and higher image quality scores.

Myocardial blood flow at rest and stress measured with dynamic contrast-enhanced MRI: comparison of a distributed parameter model with a Fermi function model.

PURPOSE: To assess the feasibility of simultaneously measuring blood flow (Fb ), Gd-DTPA extraction fraction (E), and distribution volume (vd ) in healthy myocardium at rest and under adenosine stress using dynamic contrast-enhanced MRI. METHODS: Sixteen volunteers were examined at 1.5 T and 11 returned for a repeat study. The data were analyzed using a distributed parameter (DP) 2-region model to arrive at estimates of Fb , E, blood volume, and interstitial volume. For comparison, estimates of Fb were also obtained using a Fermi function model. RESULTS: DP model fits were successful in 49 of the 54 data sets. Estimates obtained using DP and Fermi models did not differ for either rest Fb or myocardial perfusion reserve though DP estimates of stress Fb were lower than Fermi estimates. The repeatability of the DP parameters Fb , E, and vd was better than or equal to the repeatability of Fermi-Fb . E at rest and under stress was estimated to be 66% and 57%, respectively. CONCLUSION: The results suggest that characteristics of the microvasculature of healthy myocardium can be reliably determined using dynamic contrast-enhanced MRI at rest and under stress and that delivery of Gd-DTPA to the myocardium is not flow-limited.

Reproducibility of first-pass cardiovascular magnetic resonance myocardial perfusion.

PURPOSE: To assess the reproducibility of semiquantitative and quantitative analysis of first-pass myocardial perfusion cardiovascular magnetic resonance (CMR) in healthy volunteers. MATERIALS AND METHODS: Eleven volunteers underwent myocardial perfusion CMR during adenosine stress and rest on 2 separate days. Perfusion data were acquired in a single mid-ventricular section in two cardiac phases to permit cardiac phase reproducibility comparisons. Semiquantitative analysis was performed to derive normalized upslopes of myocardial signal intensity profiles (myocardial perfusion index, MPI). The quantitative analysis estimated absolute myocardial blood flow (MBF) using Fermi-constrained deconvolution. The perfusion reserve index was calculated by dividing stress by rest data. Two observers performed all the measurements independently. One observer repeated all first scan measurements 4 weeks later. RESULTS: The reproducibility of perfusion CMR was highest for semiquantitative analysis with an intraobserver coefficient of variability (CoV) of 3%-7% and interobserver CoV of 4%-10%. Semiquantitative interstudy comparison was less reproducible (CoV of 13%-27%). Quantitative intraobserver CoV of 10%-18%, interobserver CoV of 8%-15% and interstudy CoV of 20%-41%. Reproducibility of systolic and diastolic phases and the endocardial and epicardial myocardial layer showed similar reproducibility on both semiquantitative and quantitative analysis. CONCLUSION: The reproducibility of CMR myocardial perfusion estimates is good, but varies between intraobserver, interobserver, and interstudy comparisons. In this study semiquantitative analysis was more reproducible than quantitative analysis.

Subclinical Systemic Sclerosis Primary Heart Involvement by Cardiovascular Magnetic Resonance Shows No Significant Interval Change.

OBJECTIVE: Subclinical systemic sclerosis (SSc) primary heart involvement is commonly described. Whether these findings progress over time is not clear. The study aimed to investigate cardiovascular magnetic resonance (CMR) interval change of subclinical SSc primary heart involvement. METHODS: Patients with SSc with no cardiovascular disease underwent two CMR scans that included T1 mapping and quantitative stress perfusion. The CMR change (mean difference) and association between CMR measures and clinical phenotype were assessed. The study had a prospective design. RESULTS: Thirty-one patients with SSc participated, with a median (interquartile range) follow-up of 33 (17-37) months (10 [32%] in the diffuse subset, 16 [52%] with interstitial lung disease [ILD], and 11 [29%] who were Scl-70+). Four of thirty-one patients had focal late gadolinium enhancement (LGE) at visit 1; one of four had an increase in LGE scar mass between visits. Two patients showed new focal LGE at visit 2. No change in other CMR indices was noted. The three patients with SSc with increased or new LGE at visit 2 had diffuse cutaneous SSc with ILD, and two were Scl-70+. A reduction in forced vital capacity and total lung capacity was associated with a reduction in left ventricular ejection fraction (ρ = 0.413, P = 0.021; ρ = 0.335, P = 0.07) and myocardial perfusion reserve (MPR) (ρ = 0.543, P = 0.007; ρ = 0.627, P = 0.002). An increase in the N-terminal pro-brain natriuretic peptide level was associated with a reduction in MPR (ρ = -0.448, P = 0.042). Patients on disease-modifying antirheumatic drugs (DMARDs) had an increase in native T1 (mean [SD] 1208 [65] vs. 1265 [56] milliseconds, P = 0.008). No other clinically meaningful CMR change in patients receiving DMARDs or vasodilators was noted. CONCLUSION: Serial CMR detects interval subclinical SSc primary heart involvement progression; however, this study suggests abnormalities remain largely stable with follow-up.

Systolic versus diastolic acquisition in myocardial perfusion MR imaging.

PURPOSE: To compare myocardial blood flow (MBF) at systole and diastole and determine the diagnostic accuracy of both phases in patients suspected of having coronary artery disease (CAD). MATERIALS AND METHODS: The study was approved by the regional ethics committee, and all patients gave written informed consent. After coronary angiography, 40 patients (27 men; mean age, 64 years ± 8) underwent stress-rest perfusion magnetic resonance (MR) imaging at 1.5 T, with images aquired simultaneously at end systole and middiastole. Patients were classified as having CAD (stenosis .70%) or no significant CAD. In patients with CAD, myocardial segments were classified as stenosis-dependent (downstream of significant stenosis) or remote. MBF and myocardial perfusion reserve (MPR) were calculated for each segment, and mean values in each phase were compared with paired t tests. The diagnostic accuracy of each phase was determined with receiver operating characteristic (ROC) analysis. RESULTS: Twenty-one of the 40 patients (53%) had CAD. Resting MBF was similar in both phases for patients with and patients without CAD (P > .05). Stress MBF was greater in diastole than systole in normal, remote, and stenosis-dependent segments (3.75 mL/g/min ± 1.50 vs 3.15 mL/g/min ± 1.10, respectively, for normal segments; 2.75 mL/g/min ± 1.20 vs 2.38 mL/g/min ± 0.99, respectively, for remote segments; 2.49 mL/g/min ± 1.07 vs 2.23 mL/g/min ± 0.90, respectively, for stenosis-dependent segments; P <.01). MPR was greater in diastole than systole in all segment groups (P < .05). The diagnostic accuracies at diastole and systole were similar (area under the ROC curve = 0.79 and 0.82, respectively; P = .30). CONCLUSION: Myocardial perfusion MR estimates of stress MBF and MPR were greater in diastole than systole in patients with and patients without CAD. However, both phases had similar diagnostic accuracy. These observations may be relevant to other dynamic perfusion methods, including computed tomography and echocardiography.

Cardiovascular magnetic resonance physics for clinicians: Part II.

This is the second of two reviews that is intended to cover the essential aspects of cardiovascular magnetic resonance (CMR) physics in a way that is understandable and relevant to clinicians using CMR in their daily practice. Starting with the basic pulse sequences and contrast mechanisms described in part I, it briefly discusses further approaches to accelerate image acquisition. It then continues by showing in detail how the contrast behaviour of black blood fast spin echo and bright blood cine gradient echo techniques can be modified by adding rf preparation pulses to derive a number of more specialised pulse sequences. The simplest examples described include T2-weighted oedema imaging, fat suppression and myocardial tagging cine pulse sequences. Two further important derivatives of the gradient echo pulse sequence, obtained by adding preparation pulses, are used in combination with the administration of a gadolinium-based contrast agent for myocardial perfusion imaging and the assessment of myocardial tissue viability using a late gadolinium enhancement (LGE) technique. These two imaging techniques are discussed in more detail, outlining the basic principles of each pulse sequence, the practical steps required to achieve the best results in a clinical setting and, in the case of perfusion, explaining some of the factors that influence current approaches to perfusion image analysis. The key principles of contrast-enhanced magnetic resonance angiography (CE-MRA) are also explained in detail, especially focusing on timing of the acquisition following contrast agent bolus administration, and current approaches to achieving time resolved MRA. Alternative MRA techniques that do not require the use of an endogenous contrast agent are summarised, and the specialised pulse sequence used to image the coronary arteries, using respiratory navigator gating, is described in detail. The article concludes by explaining the principle behind phase contrast imaging techniques which create images that represent the phase of the MR signal rather than the magnitude. It is shown how this principle can be used to generate velocity maps by designing gradient waveforms that give rise to a relative phase change that is proportional to velocity. Choice of velocity encoding range and key pitfalls in the use of this technique are discussed.

Role of quantification of hepatic steatosis and future remnant volume in predicting hepatic dysfunction and complications after liver resection for colorectal metastases: a pilot study.

OBJECTIVES: Accurate prediction of safe remnant liver volume to minimize complications following liver resection remains challenging. The aim of this study was to assess whether quantification of steatosis improved the predictive value of preoperative volumetric analysis. METHODS: Thirty patients undergoing planned right or extended right hemi-hepatectomy for colorectal metastases were recruited prospectively. Magnetic resonance imaging was used to assess the level of hepatic steatosis and future remnant liver volume. These data were correlated with data on postoperative hepatic insufficiency, complications and hospital stay. Correlations of remnant percentage, remnant mass to patient mass and remnant mass to body surface area with and without steatosis measurements were assessed. RESULTS: In 10 of the 30 patients the planned liver resection was altered. Moderate-severe postoperative hepatic dysfunction was seen in 17 patients. Complications arose in 14 patients. The median level of steatosis was 3.8% (range: 1.2-17.6%), but was higher in patients (n= 10) who received preoperative chemotherapy (P= 0.124), in whom the median level was 4.8% (range: 1.5-17.6%). The strongest correlation was that of remnant liver mass to patient mass (r= 0.77, P < 0.001). However, the addition of steatosis quantification did not improve this correlation (r= 0.76, P < 0.001). CONCLUSIONS: This is the first study to combine volumetric with steatosis quantifications. No significant benefit was seen in this small pilot. However, these techniques may be useful in operative planning, particularly in patients receiving preoperative chemotherapy.

Clinical associations with stage B heart failure in adults with type 2 diabetes.

BACKGROUND: There is a high prevalence of asymptomatic (American Heart Association Stage B) heart failure (SBHF) in people with type 2 diabetes (T2D). We aimed to identify associations between clinical characteristics and markers of SBHF in adults with T2D, which may allow therapeutic interventions prior to symptom onset. METHODS: Adults with T2D from a multi-ethnic population with no prevalent cardiovascular disease [n = 247, age 52 ± 12 years, glycated haemoglobin A1c (HbA1c) 7.4 ± 1.1% (57 ± 12 mmol/mol), duration of diabetes 61 (32, 120) months] underwent echocardiography and adenosine stress perfusion cardiovascular magnetic resonance imaging. Multivariable linear regression analyses were performed to identify independent associations between clinical characteristics and markers of SBHF. RESULTS: In a series of multivariable linear regression models containing age, sex, ethnicity, smoking history, number of glucose-lowering agents, systolic blood pressure (BP) duration of diabetes, body mass index (BMI), HbA1c, serum creatinine, and low-density lipoprotein (LDL)-cholesterol, independent associations with: left ventricular mass:volume were age (ß = 0.024), number of glucose-lowering agents (ß = 0.022) and systolic BP (ß = 0.027); global longitudinal strain were never smoking (ß = -1.196), systolic BP (ß = 0.328), and BMI (ß = -0.348); myocardial perfusion reserve were age (ß = -0.364) and male sex (ß = 0.458); and aortic distensibility were age (ß = -0.629) and systolic BP (ß = -0.348). HbA1c was not independently associated with any marker of SBHF. CONCLUSIONS: In asymptomatic adults with T2D, age, systolic BP, BMI, and smoking history, but not glycaemic control, are the major determinants of SBHF. Given BP and BMI are modifiable, these may be important targets to reduce the development of symptomatic heart failure.