Chronic fatigue syndrome in women assessed with combined cardiac magnetic resonance imaging

Objective

In chronic fatigue syndrome (CFS), only a few imaging and histopathological studies have previously assessed either cardiac dimensions/function or myocardial tissue, suggesting smaller left ventricular (LV) dimensions, LV wall motion abnormalities and occasionally viral persistence that may lead to cardiomyopathy. The present study with cardiac magnetic resonance (CMR) imaging is the first to use a contrast-enhanced approach to assess cardiac involvement, including tissue characterisation of the LV wall.

Methods

CMR measurements of 12 female CFS patients were compared with data of 36 age-matched, healthy female controls. With cine imaging, LV volumes, ejection fraction (EF), mass, and wall motion abnormalities were assessed. T2-weighted images were analysed for increased signal intensity, reflecting oedema (i. e. inflammation). In addition, the presence of contrast enhancement, reflecting fibrosis (i. e. myocardial damage), was analysed.

Results

When comparing CFS patients and healthy controls, LVEF (57.9 ± 4.3 % vs. 63.7 ± 3.7 %; p < 0.01), end-diastolic diameter (44 ± 3.7 mm vs. 49 ± 3.7 mm; p < 0.01), as well as body surface area corrected LV end-diastolic volume (77.5 ± 6.2 ml/m² vs. 86.0 ± 9.3 ml/m²; p < 0.01), stroke volume (44.9 ± 4.5 ml/m² vs. 54.9 ± 6.3 ml/m²; p < 0.001), and mass (39.8 ± 6.5 g/m² vs. 49.6 ± 7.1 g/m²; p = 0.02) were significantly lower in patients. Wall motion abnormalities were observed in four patients and contrast enhancement (fibrosis) in three; none of the controls showed wall motion abnormalities or contrast enhancement. None of the patients or controls showed increased signal intensity on the T2-weighted images.

Conclusion

In patients with CFS, CMR demonstrated lower LV dimensions and a mildly reduced LV function. The presence of myocardial fibrosis in some CFS patients suggests that CMR assessment of cardiac involvement is warranted as part of the scientific exploration, which may imply serial non-invasive examinations.

Contrast-enhancement cardiac magnetic resonance imaging beyond the scope of viability

The clinical applications of cardiovascular magnetic resonance imaging with contrast enhancement are expanding. Besides the direct visualisation of viable and non-viable myocardium, this technique is increasingly used in a variety of cardiac disorders to determine the exact aetiology, guide proper treatment, and predict outcome and prognosis. In this review, we discuss the value of cardiovascular magnetic resonance imaging with contrast enhancement in a range of cardiac disorders, in which this technique may provide insights beyond the scope of myocardial viability.

The importance of cardiac MRI as a diagnostic tool in viral myocarditis-induced cardiomyopathy

Myocarditis is an acute or chronic inflammatory disease of the myocardium which can be viral, postinfectious immune or primarily organ-specific autoimmune. Clinical manifestations of acute and chronic myocarditis are extremely varied, ranging from mild to severe. Affected patients may recover or develop (dilated) cardiomyopathy (DCM) with life-threatening symptoms including heart failure, conduction disturbances, arrhythmias, cardiogenic shock or sudden cardiac death.The diagnosis of myocarditis is a challenging process and not only because of a diverse presentation; other problems are limited sensitivity of endomyocardial biopsies (EMB) and overlapping symptoms. Furthermore, the diagnosis is not well defined. However, early diagnosis is mandatory to address specific aetiology-directed therapeutic management in myocarditis that influences patient morbidity and mortality.Currently, EMB remains the only way to confirm the presence of a viral genome and other histopathological findings allowing proper treatment to be implemented in cases of myocarditis. Increased recognition of the role of myocardial inflammatory changes has given rise to interest in noninvasive imaging as a diagnostic tool, especially cardiovascular magnetic resonance imaging (CMR). In this review we discuss the current role of CMR in the evaluation of myocarditis-induced inflammatory cardiomyopathies. (Neth Heart J 2009;17:481-6.).

Arrhythmogenic right ventricular dysplasia as a possible cause of sudden cardiac death: a case report and clinical review

Sudden cardiac death can be described as an unexplained natural death due to a cardiac cause. It occurs within a short period, one hour or less, after onset of symptoms in a person without any prior medical history. Among the many causes of unexplained sudden cardiac death, we would like to specifically discuss arrhythmogenic right ventricular dysplasia as a rare cause in otherwise healthy and usually young individuals.

A practical approach to MRI of coronary artery bypass graft patency and flow

Direct visualization of coronary artery bypass grafts can be obtained non-invasively by magnetic resonance imaging. Several studies demonstrated a high sensitivity and somewhat lower specificity for detection of vein-graft patency, using the conventional spin-echo and gradient-echo techniques. In addition, the true functional status can be assessed by determining the flowrate within the graft using phase velocity mapping. Important limitations of the previously applied techniques include the inability to accurately evaluate the different segments of jump grafts and the presence of graft stenoses. Further improvement is to be expected from the recent introduction of breath-hold imaging sequences and the forthcoming introduction of bloodpool-avid contrast agents.

Value of magnetic resonance imaging in assessing patency and function of coronary artery bypass grafts. An angiographically controlled study

BACKGROUND

Previous studies have demonstrated the high sensitivity and moderate specificity of standard magnetic resonance (MR) spin-echo (SE) and gradient-echo (GE) techniques in predicting the patency of coronary artery bypass grafts. These techniques, however, do not provide quantitative information. Therefore, the objectives of this study were first to investigate whether MR cine GE images, performed in addition to standard SE images, have additional value for the assessment of graft patency and second to assess the graft function by measuring the flow pattern and flow rate with MR phase velocity imaging.

METHODS AND RESULTS

Forty-seven patients with previous histories of coronary artery bypass grafting underwent angiography and MR SE and cine GE phase velocity imaging. SE and GE images were evaluated by three independent observers blinded to the angiographic results. The spatial mean velocity and volume flow were measured and repeated for each image at consecutive 50-millisecond intervals throughout the cardiac cycle. The 47 patients had 98 proximal aortotomies, of which 60 were single and 38 sequential grafts. Seventy-three grafts were patent; 25 were occluded. Eighty-four grafts (86%) were eligible for comparison of the results of SE and GE images. Assessment of patency was inconclusive on SE images in 7 grafts (5 occluded by angiography) and on GE images in 7 grafts (2 occluded). A comparison of the results of contrast angiography and SE and GE MR imaging techniques showed that both techniques had a high sensitivity (both 98%) and somewhat lower specificity (85% and 88%, respectively) for graft patency. Combined analysis of the SE and GE images did not improve the accuracy. The strength of the interobserver agreement on GE images was good (kappa = 0.66), whereas on SE images the agreement was moderate (kappa = 0.51). Adequate MR phase velocity profiles were obtained in 62 (85%) of the 73 angiographically patent grafts. Graft flow was characterized by a balanced biphasic forward flow pattern. The volume flow of sequential grafts to 3 regions (136 +/- 106 mL/min) was significantly higher than in single grafts (63 +/- 41 mL/min, P < .01).

CONCLUSIONS

Considering the good interobserver agreement and the 85% success rate of quantitative flow measurements, cine GE phase velocity mapping is a promising clinical tool in the noninvasive assessment of graft patency and function.

Quantification of coronary artery bypass graft flow by magnetic resonance phase velocity mapping

OBJECTIVES

Determination of the true coronary artery bypass graft function requires quantification of the flow rate within the graft. The purpose of the present study was to assess the feasibility of characterizing and quantifying graft flow by magnetic resonance phase velocity mapping.

MATERIALS AND METHODS

Twenty-seven patients with 41 angiographically patent coronary artery bypass grafts underwent electrocardiographically gated magnetic resonance phase velocity mapping. Imaging was performed at 0.6 Tesla using a surface coil. Velocity maps of the bypass grafts were obtained throughout the cardiac cycle with a temporal resolution of 50 ms and a spatial resolution of 1.9 x 1.2 x 5 mm3, allowing calculation of phasic and mean graft flow.

RESULTS

Adequate flow measurements were obtained in 84% (41 out of 49) of the grafts. Coronary artery bypass graft flow was characterized by a biphasic pattern with a first peak during systole and a second peak during diastole. Average maximum systolic and diastolic velocities over the cross-section of the grafts were 14 +/- 8 cm/s and 15 +/- 9 cm/s, respectively. Mean coronary artery bypass graft cross-sectional area was 0.28 +/- 0.13 cm2. Mean volume flow was 87 +/- 59 ml/min.

CONCLUSION

Flow in coronary artery bypass grafts can be characterized and measured noninvasively by magnetic resonance phase velocity mapping.

Magnetic resonance imaging of the pulmonary venous flow pattern in mitral regurgitation. Independence of the investigated vein

OBJECTIVES

The aim of the present study was two-fold: first, to quantify characteristic parameters of the pulmonary venous flow pattern in patients with mitral regurgitation by using magnetic resonance phase velocity mapping; second, to determine whether this pattern is dependent on the vein being investigated and the direction of the regurgitant jet.

BACKGROUND

Echocardiographic findings threw doubt on whether the pulmonary venous flow pattern is independent of the vein being investigated and whether the flow velocities in the pulmonary veins have a linear relationship with the volume flow.

SUBJECTS AND METHODS

Flow patterns were assessed in all four pulmonary veins by magnetic resonance velocity mapping in healthy volunteers and in 17 patients with echocardiographically mild and 13 patients with severe regurgitation.

RESULTS

No differences were found between the use of velocity or volume flow for characterizing individual curves. The pulmonary venous flow pattern in controls was characterized by six points, a biphasic systolic wave (maximum systolic volume flow: 29 +/- 18 ml.s-1), and end-systolic descent (24 +/- 18 ml.s-1), a biphasic diastolic wave (maximum diastolic volume flow: 69 +/- 22 ml.s-1) and an end-diastolic reversed flow. Reversed end-systolic flow was a characteristic sign of severe regurgitation (-10 +/- 18 ml.s-1). The systolic-to-diastolic flow ratio was lower in severe regurgitation (0.5 +/- 0.6) than in mild regurgitation (1.4 +/- 0.9), P < 0.0001). In severe regurgitation, the normalized time intervals from Q wave to the highest systolic peak and end-systolic descent were of less prolonged duration than in mild regurgitation and controls (P < 0.01). Flow patterns between veins were similar and the median of the correlation coefficients between the curves was the same in patients with or without an eccentric jet, 0.80 and 0.81, respectively.

CONCLUSION

Magnetic resonance velocity mapping is helpful in determining and understanding pulmonary venous flow characteristics. It is demonstrated that the pulmonary venous flow pattern is independent of the vein being investigated irrespective of the regurgitant jet direction, and that it is useful in grading mitral regurgitation.

The role of magnetic resonance in the evaluation of functional results after CABG/PTCA

Magnetic resonance imaging (MRI) is a non-invasive modality which can be used for direct visualization of coronary artery bypass grafts. Spin-echo and gradient-echo (cine-MRI) techniques are now available on standard MR machines and provide information on graft morphology and graft patency with a 90% accuracy. By combining the standard techniques with MR phase velocity mapping, the flow rate in the graft can be measured, thereby offering a unique non-invasive assessment of the graft function. Newer techniques include MR coronary angiography, pharmacologically induced stress MRI, ultrafast MRI of the first-pass (perfusion) of a paramagnetic contrast agent through the myocardium, and 31P MR spectroscopy of high-energy phosphate metabolism of the myocardium. All of these may develop into valuable diagnostic tools for the assessment of functional results after CABG or PTCA, but still require clinical validation. At present, MRI is a useful screening procedure for assessment of graft patency and function in post-operative pain syndromes and in late graft occlusion or stenosis.

The prognostic value, clinical, and angiographic characteristics of patients with early postinfarction angina after a first myocardial infarction

To evaluate the prognostic value of early postinfarction angina and its relationship to clinical and angiographic variables, 231 consecutive patients who had a first myocardial infarction were studied. All underwent cardiac catheterization within 10 weeks after admission to the hospital. There were no differences in basic characteristics or in ejection fraction, extent or severity of coronary artery disease, or collateral circulation between the patients with early postinfarction angina (n = 27) and those without early postinfarction angina (n = 204) except for the incidence of angina before myocardial infarction. Patients with early postinfarction angina had exercise-induced angina (42% vs 21%; p < 0.025) more frequently and shorter exercise duration (6.9 +/- 2.5 minutes vs 8.3 +/- 2.5 minutes; p = 0.007). Early postinfarction angina was associated with a significantly higher event rate (15% vs 4%; p < 0.025) and a significantly higher mortality rate (15% vs 3%; p < 0.005) in the first year after infarction but not during the subsequent 4-year follow-up. In patients with early postinfarction angina, stress test results had no predictive value for future cardiac events in contrast to patients without early postinfarction angina in whom ST-segment depression as observed on the stress test ECG and exercise duration had predictive value for future cardiac events. In patients with early postinfarction angina there was no relationship between the incidence of events and the number of diseased vessels in contrast to patients without early postinfarction angina who had a high incidence of events when three-vessel disease was present (16% vs 62%; p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Global left ventricular perfusion: noninvasive measurement with cine MR imaging and phase velocity mapping of coronary venous outflow

Velocity and volumetric flow of left ventricular venous outflow in the distal coronary sinus were measured with magnetic resonance (MR) velocity mapping techniques in 24 healthy men. A total of 16-21 velocity maps were acquired throughout the cardiac cycle. To determine the accuracy of the MR velocity-mapping pulse sequence, measurements were obtained with a flow phantom. Mean blood flow was 144 mL/min +/- 62 (standard deviation); mean velocity, 2.1 cm/sec +/- 1.0; and mean cross-sectional area, 1.2 cm2. Phasic measurements revealed a biphasic flow pattern in the coronary sinus, with a first peak in systole (257 mL/min +/- 174) and a second peak in early diastole (1,090 mL/min +/- 487). The cross-sectional area varied between 0.5 cm2 +/- 0.2 at end diastole and 1.9 cm2 +/- 0.6 in systole, a finding that suggests a capacitance function for venous outflow. Mean blood flow measurements were in agreement with measurements obtained invasively in previous studies. It is concluded that MR velocity mapping can enable noninvasive measurement of coronary venous outflow and global left ventricular perfusion and may become clinically useful in assessment of coronary blood flow reserve.