-
Theodoros D Karamitsos,
Stefan K Piechnik,
Sanjay M Banypersad,
Marianna Fontana,
Ntobeko B Ntusi,
Vanessa M Ferreira,
Carol J Whelan, Saul G Myerson,
Matthew D Robson,
Philip N Hawkins,
Stefan Neubauer,
James C Moon
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVES: This study sought to explore the potential role of noncontrast myocardial T1 mapping for detection of cardiac involvement in patients with primary amyloid light-chain (AL) amyloidosis. BACKGROUND: Cardiac involvement carries a poor prognosis in systemic AL amyloidosis. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is useful for the detection of cardiac amyloid, but characteristic LGE patterns do not always occur or they appear late in the disease. Noncontrast characterization of amyloidotic myocardium with T1 mapping may improve disease detection. Furthermore, quantitative assessment of myocardial amyloid load would be of great value. METHODS: Fifty-three AL amyloidosis patients (14 with no cardiac involvement, 11 with possible involvement, and 28 with definite cardiac involvement based on standard biomarker and echocardiographic criteria) underwent CMR (1.5-T) including noncontrast T1 mapping (shortened modified look-locker inversion recovery [ShMOLLI] sequence) and LGE imaging. These were compared with 36 healthy volunteers and 17 patients with aortic stenosis and a comparable degree of left ventricular hypertrophy as the cardiac amyloid patients. RESULTS: Myocardial T1 was significantly elevated in cardiac AL amyloidosis patients (1,140 ± 61 ms) compared to normal subjects (958 ± 20 ms, p < 0.001) and patients with aortic stenosis (979 ± 51 ms, p < 0.001). Myocardial T1 was increased in AL amyloid even when cardiac involvement was uncertain (1,048 ± 48 ms) or thought absent (1,009 ± 31 ms). A noncontrast myocardial T1 cutoff of 1,020 ms yielded 92% accuracy for identifying amyloid patients with possible or definite cardiac involvement. In the AL amyloidosis cohort, there were significant correlations between myocardial T1 time and indices of systolic and diastolic dysfunction. CONCLUSIONS: Noncontrast T1 mapping has high diagnostic accuracy for detecting cardiac AL amyloidosis, correlates well with markers of systolic and diastolic dysfunction, and is potentially more sensitive for detecting early disease than LGE imaging. Elevated myocardial T1 may represent a direct marker of cardiac amyloid load. Further studies are needed to assess the prognostic significance of T1 elevation.
JACC. Cardiovascular imaging 03/2013; · 14.29 Impact Factor
-
Sacha Bull,
Steven K White,
Stefan K Piechnik,
Andrew S Flett,
Vanessa M Ferreira,
Margaret Loudon,
Jane M Francis,
Theodoros D Karamitsos,
Bernard D Prendergast,
Matthew D Robson,
Stefan Neubauer,
James C Moon, Saul G Myerson
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Aortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition. OBJECTIVE: To test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent. DESIGN, SETTING AND PATIENTS: A prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls. METHODS: CMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look-Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement. RESULTS: There was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972±33 ms in severe asymptomatic, 1014±38 ms in severe symptomatic) than in normal controls (944±16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=-0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis. CONCLUSIONS: Non-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future.
Heart (British Cardiac Society) 01/2013; · 4.22 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVES: Infective endocarditis (IE) is a severe complication in Staphylococcus aureus bacteraemia (SAB) and recent guidelines from the BSAC recommend all patients undergo echocardiography. We assessed the use of echocardiography at a major tertiary referral centre and sought to identify those patients most likely to have positive findings. METHODS: We retrospectively evaluated all cases of SAB at Oxford University Hospitals NHS Trust between September 2006 and August 2011. RESULTS: Three-hundred-and-six out of 668 patients with SAB underwent cardiac imaging on average 9.8 ± 1.3 days from the first culture. Thirty-one patients (10.1%) had echocardiographic evidence of IE. Risk factors for observing evidence of IE on scanning included the presence of prosthetic heart valves (32% versus 4%, P < 0.001) or cardiac rhythm management (CRM) devices (16% versus 3%, P < 0.004). On excluding patients with prosthetic valves or CRM devices from the analysis, no patient with a line-related bacteraemia and only one patient (an intravenous drug user) with no/mild regurgitation on transthoracic echocardiography had echo evidence of IE. CONCLUSIONS: We propose that the use of scarce echocardiography resources could be prioritized. Patients with prosthetic heart valves or a CRM device should receive early cardiological input and transoesophageal echocardiography. In patients with a clearly defined line-related bacteraemia who do not have a prosthetic valve or CRM device or clinical features of IE, response to treatment could be closely monitored and imaging deferred. Patients without a line-related infection or prosthetic valve/device could receive a transthoracic echocardiogram as a screening tool.
Journal of Antimicrobial Chemotherapy 10/2012; · 5.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Current indications for surgery in patients with significant aortic regurgitation (AR) focus on symptoms and left ventricular dilation/dysfunction. However, prognosis is already reduced by this stage, and earlier identification of patients for surgery could be beneficial. Quantifying the regurgitation may help, but there are limited data on its link with outcome. Cardiovascular magnetic resonance (CMR) can accurately quantify AR, and we examined whether this was associated with the future need for surgery.
One hundred thirteen patients with echocardiographic moderate or severe AR were monitored for up to 9 years (mean 2.6±2.1 years) following a CMR scan, and the progression to symptoms or other indications for surgery was monitored. AR quantification identified outcome with high accuracy: 85% of the 39 subjects with regurgitant fraction >33% progressed to surgery (mostly within 3 years) in comparison with 8% of 74 subjects with regurgitant fraction ≤33% (P<0.0001); the area under the curve on receiver operating characteristic analysis was 0.93 (P<0.0001). This ability remained strong on time-dependent Kaplan-Meier survival curves. CMR-derived left ventricular end-diastolic volume >246 mL had good, although lower, discriminatory ability (area under the curve 0.88), but the combination of this measure with regurgitant fraction provided the best discriminatory power.
High degrees of CMR-quantified AR were associated with the development of symptoms or other indications for surgery. Quantifying AR showed slightly better discriminatory ability than "gold standard" CMR ventricular volume assessment. This could provide a new paradigm for the timing of surgical intervention but requires confirmation in a clinical trial.
Circulation 08/2012; 126(12):1452-60. · 14.74 Impact Factor
-
Sacha Bull,
Alex Pitcher,
Jane M Francis,
Joseph Suttie,
Jubin Joseph,
Joanna D’Arcy,
Bernard Prendergast,
Harald Becher,
Theo D Karamitsos,
Stefan Neubauer, Saul G Myerson
Journal of Cardiovascular Magnetic Resonance 05/2012; 13:1-2. · 3.72 Impact Factor
-
Alex Pitcher,
Tom E Cassar,
Joseph Suttie,
Jane M Francis,
Paul Leeson,
Edward Blair,
B Paul Wordsworth,
Colin J Forfar, Saul G Myerson,
Michael Markl,
Stefan Neubauer,
Steffen E Petersen
Journal of Cardiovascular Magnetic Resonance 05/2012; 13:1-3. · 3.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: IntroductionAdenosine is the most widely used vasodilator stress agent for Cardiovascular Magnetic Resonance (CMR) perfusion studies.
With the standard dose of 140 mcg/kg/min some patients fail to demonstrate characteristic haemodynamic changes: a significant
increase in heart rate (HR) and mild decrease in systolic blood pressure (SBP). Whether an increase in the rate of adenosine
infusion would improve peripheral and, likely, coronary vasodilatation in those patients is unknown. The aim of the present
study was to assess the tolerance and safety of a high-dose adenosine protocol in patients with inadequate haemodynamic response
to the standard adenosine protocol when undergoing CMR perfusion imaging.
Methods98 consecutive patients with known or suspected coronary artery disease (CAD) underwent CMR perfusion imaging at 1.5 Tesla.
Subjects were screened for contraindications to adenosine, and an electrocardiogram was performed prior to the scan. All patients
initially received the standard adenosine protocol (140 mcg/kg/min for at least 3 minutes). If the haemodynamic response was
inadequate (HR increase < 10 bpm or SBP decrease < 10 mmHg) then the infusion rate was increased up to a maximum of 210 mcg/kg/min
(maximal infusion duration 7 minutes).
ResultsAll patients successfully completed the CMR scan. Of a total of 98 patients, 18 (18%) did not demonstrate evidence of a significant
increase in HR or decrease in SBP under the standard adenosine infusion rate. Following the increase in the rate of infusion,
16 out of those 18 patients showed an adequate haemodynamic response. One patient of the standard infusion group and two patients
of the high-dose group developed transient advanced AV block. Significantly more patients complained of chest pain in the
high-dose group (61% vs. 29%, p = 0.009). On multivariate analysis, age > 65 years and ejection fraction < 57% were the only
independent predictors of blunted haemodynamic responsiveness to adenosine.
ConclusionsA substantial number of patients do not show adequate peripheral haemodynamic response to standard-dose adenosine stress during
perfusion CMR imaging. Age and reduced ejection fraction are predictors of inadequate response to standard dose adenosine.
A high-dose adenosine protocol (up to 210 mcg/kg/min) is well tolerated and results in adequate haemodynamic response in nearly
all patients.
Journal of Cardiovascular Magnetic Resonance 04/2012; 12(1):1-8. · 3.72 Impact Factor
-
Progress in Nuclear Magnetic Resonance Spectroscopy 10/2011; 59(3):213-22. · 5.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The diagnostic evaluation of patients with isolated left bundle branch block (LBBB) is challenging due to limitations of several non-invasive tests. Our aim was to evaluate the diagnostic value of cardiovascular magnetic resonance (CMR) in asymptomatic patients with LBBB. Sixty-one asymptomatic patients with complete LBBB who were referred for CMR from January 2005 to November 2010 were identified. 29 patients (18 men) had normal echocardiograms (echo) whereas 25 (18 men) had abnormal findings on echo. Six had no echo and one had poor echo windows, and these patients were excluded from further analysis. Patients with cardiac symptoms or known coronary artery disease at the time of referral were also excluded. Of the 29 patients with normal echo, 9 (31%) were found to have pathological findings on CMR. The most common abnormalities were dilated cardiomyopathy-DCM (n = 6, 21%) followed by left ventricular hypertrophy (n = 2, 7%). Of the 25 patients who had an abnormal echo, CMR confirmed the diagnosis in 19 (76%) and provided clinically relevant additional information in 13 (52%) subjects. Of these 13 patients, 9 (69%) had characteristic patterns of myocardial late gadolinium enhancement (8 mid-wall and 1 patchy distribution consistent with DCM and cardiac sarcoid, respectively). CMR detects sub-clinical cardiomyopathy in a third of asymptomatic patients with LBBB despite normal echocardiograms. In those with abnormal echocardiograms, CMR provides additional clinically relevant information in over 50% of patients, including a high prevalence of mid-wall fibrosis in patients with impaired left ventricular function. These findings support the use of CMR as a valuable adjunct to conventional investigations in asymptomatic LBBB.
The international journal of cardiovascular imaging 07/2011; 28(5):1133-40. · 2.15 Impact Factor
-
The international journal of cardiovascular imaging 04/2011; 27(4):571. · 2.15 Impact Factor
-
Circulation 03/2011; 123(10):e370-2. · 14.74 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Stress perfusion CMR can provide both excellent diagnostic and important prognostic information in the context of a comprehensive assessment of cardiac anatomy and function. This coupled with the high spatial resolution, and the lack of both attenuation artefacts and ionising radiation, make CMR stress perfusion imaging a highly attractive stress imaging modality. It is now in routine use in many centres, and shows promise in evaluating patients with clinical problems beyond those of epicardial coronary disease.
Heart Lung & Circulation 12/2010; 19(12):697-705. · 1.20 Impact Factor
-
Journal of the American College of Cardiology 11/2010; 56(23):1961. · 14.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Adenosine is the most widely used vasodilator stress agent for cardiovascular magnetic resonance (CMR) perfusion studies. With the standard dose of 140 mcg/kg/min some patients fail to demonstrate characteristic haemodynamic changes: a significant increase in heart rate (HR) and mild decrease in systolic blood pressure (SBP). Whether an increase in the rate of adenosine infusion would improve peripheral and, likely, coronary vasodilatation in those patients is unknown. The aim of the present study was to assess the tolerance and safety of a high-dose adenosine protocol in patients with inadequate haemodynamic response to the standard adenosine protocol when undergoing CMR perfusion imaging.
98 consecutive patients with known or suspected coronary artery disease (CAD) underwent CMR perfusion imaging at 1.5 Tesla. Subjects were screened for contraindications to adenosine, and an electrocardiogram was performed prior to the scan. All patients initially received the standard adenosine protocol (140 mcg/kg/min for at least 3 minutes). If the haemodynamic response was inadequate (HR increase < 10 bpm or SBP decrease < 10 mmHg) then the infusion rate was increased up to a maximum of 210 mcg/kg/min (maximal infusion duration 7 minutes).
All patients successfully completed the CMR scan. Of a total of 98 patients, 18 (18%) did not demonstrate evidence of a significant increase in HR or decrease in SBP under the standard adenosine infusion rate. Following the increase in the rate of infusion, 16 out of those 18 patients showed an adequate haemodynamic response. One patient of the standard infusion group and two patients of the high-dose group developed transient advanced AV block. Significantly more patients complained of chest pain in the high-dose group (61% vs. 29%, p = 0.009). On multivariate analysis, age > 65 years and ejection fraction < 57% were the only independent predictors of blunted haemodynamic responsiveness to adenosine.
A substantial number of patients do not show adequate peripheral haemodynamic response to standard-dose adenosine stress during perfusion CMR imaging. Age and reduced ejection fraction are predictors of inadequate response to standard dose adenosine. A high-dose adenosine protocol (up to 210 mcg/kg/min) is well tolerated and results in adequate haemodynamic response in nearly all patients.
Journal of Cardiovascular Magnetic Resonance 11/2010; 12:66. · 3.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To determine the accuracy of visual analysis of left ventricular (LV) function in comparison with the accepted quantitative gold standard method, cardiac magnetic resonance (CMR). Cine CMR imaging was performed at 1.5 T on 44 patients with a range of ejection fractions (EF, 5-80%). Clinicians (n = 18) were asked to visually assess EF after sequentially being shown cine images of a four chamber (horizontal long axis; HLA), two chamber (vertical long axis; VLA) and a short axis stack (SAS) and results were compared to a commercially available analysis package. There were strong correlations between visual and quantitative assessment. However, the EF was underestimated in all categories (by 8.4% for HLA, 8.4% for HLA + VLA and 7.9% for HLA + VLA + SAS, P all < 0.01) and particularly underestimated in mild LV impairment (17.4%, P < 0.01), less so for moderate (4.9%) and not for severe impairment (1%). Assessing more than one view of the heart improved visual assessment of LV, EF, however, clinicians underestimated EF by 8.4% on average, with particular inaccuracy in those with mild dysfunction. Given the important clinical information provided by LV assessment, quantitative analysis is recommended for accurate assessment.
The international journal of cardiovascular imaging 10/2010; 27(4):563-9. · 2.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: CMR is a comprehensive non-invasive tool capable of evaluating all aspects of valvular heart disease. It has advantages over echo including direct quantification of regurgitant lesions, highly accurate assessment of ventricular size and function, visualisation myocardial scar, and interrogation of extracardiac abnormalities. Although these gains can be realised with current scanning techniques, CMR's full potential has yet to be realised, and further studies of clinical outcomes are needed before CMR data can be integrated into the management algorithms for patients with significant valvular lesions.
Heart Lung & Circulation 10/2010; 20(2):73-82. · 1.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Quantifying mitral regurgitation with cardiovascular magnetic resonance (CMR) involves indirect calculation, which increases the potential for error. We examined a direct quantification method using velocity mapping across the mitral valve, which may be less susceptible to error, and also examined the effect of heart rate variability on both techniques.
Fifty-five patients underwent mitral regurgitation quantification with CMR by the direct method and two indirect methods-the standard method subtracting aortic flow (assessed by velocity mapping) from left ventricular stroke volume (assessed by cine imaging) and the 'volumetric' method using the difference between left and right ventricular stroke volumes. The methods were compared using Bland-Altman analyses.
Patients with low heart rate variability (beat-to-beat variability <30 bpm; n = 44) showed good agreement between direct and indirect methods (95% confidence limits for the difference between measurements +/-16.7 ml/11.8% regurgitant fraction for the standard method; +/-21.7 ml/15.4% for the volumetric method), with no significant offset (mean difference +2.8 ml/+1.9% for standard and +3.1 ml/+2.3% for volumetric methods). Patients with high heart rate variability (>30 bpm; n = 11) showed poor agreement between techniques (95% limits +/-80.3 ml/56.0%) and significant offset (mean difference +31.7 ml/+19.5%).
Direct quantification of mitral regurgitation with CMR compares well with indirect methods for patients with low heart rate variability, involves fewer calculations and is quick. All CMR measurements that use velocity mapping may be inaccurate, however, in patients with highly irregular rhythms and should be avoided in these patients.
MAGMA Magnetic Resonance Materials in Physics Biology and Medicine 09/2010; 23(4):243-9. · 1.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study assessed 3-dimensional fusion echocardiography (3DFE), combining several real-time 3-dimensional echocardiography (RT3DE) full volumes from different transducer positions, for improvement in quality and completeness of the reconstructed image.
The RT3DE technique has limited image quality and completeness of datasets even with current matrix transducers.
RT3DE datasets were acquired in 32 participants (mean age 33.7 +/- 18.8 years; 27 men, 5 women). The 3DFE technique was also performed on a cardiac phantom. The endocardial border definition of RT3DE and 3DFE segments was graded for quality: good (2), intermediate (1), poor (0), or out of sector. Short-axis and apical images were compared in RT3DE and 3DFE, yielding 2,048 segments. The images were processed to generate 3DFE and then compared with cardiac magnetic resonance.
In the heart phantom, fused datasets showed improved contrast to noise ratio from 49.4 +/- 25.1 (single dataset) to 125.4 +/- 25.1 (6 datasets fused together). In subjects, more segments were graded as good quality with 3DFE (805 vs. 435; p < 0.0001) and fewer as intermediate (184 vs. 283; p = 0.017), poor (31 vs. 265; p < 0.0001), or out of sector (4 vs. 41; p < 0.001) compared with the single 3-dimensional dataset. End-diastolic volume (EDV) and end-systolic volume (ESV) obtained from 3-dimensional fused datasets were equivalent to those from single datasets (EDV 118.2 +/- 39 ml vs. 119.7 +/- 43 ml; p = 0.41; ESV 48.1 +/- 30 ml vs. 48.4 +/- 35 ml; p = 0.87; ejection fraction [EF] 61.0 +/- 10% vs. 61.8 +/- 10%; p = 0.44). Bland-Altman analysis showed good 95% limits of agreement for the nonfused datasets (EDV +/-46 ml; ESV +/-36 ml; EF +/-14%) and the fused datasets (EDV +/-45 ml; ESV +/-35 ml; EF +/-16%), when compared with cardiac magnetic resonance.
Fusion of full-volume datasets resulted in an improvement in endocardial borders, image quality, and completeness of the datasets.
JACC. Cardiovascular imaging 07/2010; 3(7):682-90. · 14.29 Impact Factor
-
Clinical medicine (London, England) 04/2010; 10(2):172-6. · 1.15 Impact Factor
-
Saul G Myerson
[show abstract]
[hide abstract]
ABSTRACT: Cardiovascular magnetic resonance is able to provide a comprehensive assessment of valvular and hemodynamic function, including quantification of valve regurgitation and other flows, and accurate cardiac volumes and mass for assessing the effect on both ventricles. Combined with the ability to image all areas of the heart (including difficult areas, such as the right ventricle and pulmonary veins), it is an ideal technique for investigating patients who have heart failure in whom these areas need to be examined.
Heart Failure Clinics 08/2009; 5(3):389-400, vi-vii.
