Anja Wagner

Contrast-enhanced MRI and routine single photon emission computed tomography (SPECT) perfusion imaging for detection of subendocardial myocardial infarcts: an imaging study

BACKGROUNDnMyocardial infarcts are routinely detected by nuclear imaging techniques such as single photon emission computed tomography (SPECT) myocardial perfusion imaging. A newly developed technique for infarct detection based on contrast-enhanced cardiovascular magnetic resonance (CMR) has higher spatial resolution than SPECT. We postulated that this technique would detect infarcts missed by SPECT.nnnMETHODSnWe did contrast-enhanced CMR and SPECT examinations in 91 patients with suspected or known coronary artery disease. All CMR and SPECT images were scored, using a 14-segment model, for the presence, location, and spatial extent of infarction. To compare each imaging modality to a gold standard, we also acquired contrast-enhanced CMR and SPECT images in 12 dogs with, and three dogs without, myocardial infarction as defined by histochemical staining.nnnFINDINGSnIn animals, contrast-enhanced CMR and SPECT detected all segments with nearly transmural infarction (>75% transmural extent of the left-ventricular wall). CMR also identified 100 of the 109 segments (92%) with subendocardial infarction (<50% transmural extent of the left-ventricular wall), whereas SPECT identified only 31 (28%). SPECT and CMR showed high specificity for the detection of infarction (97% and 98%, respectively). In patients, all segments with nearly transmural infarction, as defined by contrast-enhanced CMR, were detected by SPECT. However, of the 181 segments with subendocardial infarction, 85 (47%) were not detected by SPECT. On a per patient basis, six (13%) individuals with subendocardial infarcts visible by CMR had no evidence of infarction by SPECT.nnnINTERPRETATIONnSPECT and CMR detect transmural myocardial infarcts at similar rates. However, CMR systematically detects subendocardial infarcts that are missed by SPECT.

Cardiovascular Magnetic Resonance Assessment of Human Myocarditis. A Comparison to Histology and Molecular Pathology

Background—Myocarditis can occasionally lead to sudden death and may progress to dilated cardiomyopathy in up to 10% of patients. Because the initial onset is difficult to recognize clinically and the diagnostic tools available are unsatisfactory, new strategies to diagnose myocarditis are needed. Methods and Results—Cardiovascular MR imaging (CMR) was performed in 32 patients who were diagnosed with myocarditis by clinical criteria. To determine whether CMR visualizes areas of active myocarditis, endomyocardial biopsy was taken from the region of contrast enhancement and submitted to histopathologic analysis. Follow-up was performed 3 month later. Contrast enhancement was present in 28 patients (88%) and was usually seen with one or several foci in the myocardium. Foci were most frequently located in the lateral free wall. In the 21 patients in whom biopsy was obtained from the region of contrast enhancement, histopathologic analysis revealed active myocarditis in 19 patients (parvovirus B19, n=12; human herpes virus type 6 [HHV 6], n=5). Conversely, in the remaining 11 patients, in whom biopsy could not be taken from the region of contrast enhancement, active myocarditis was found in one case only (HHV6). At follow-up, the area of contrast enhancement decreased from 9±11% to 3±4% of left ventricular mass as the left ventricular ejection fraction improved from 47±19% to 60±10%. Conclusions—Contrast enhancement is a frequent finding in the clinical setting of suspected myocarditis and is associated with active inflammation defined by histopathology. Myocarditis occurs predominantly in the lateral free wall. Contrast CMR is a valuable tool for the evaluation and monitoring of inflammatory heart disease.

Presentation, Patterns of Myocardial Damage, and Clinical Course of Viral Myocarditis

Background— Enteroviruses and adenoviruses have been considered the most common causes of viral myocarditis, but parvovirus B19 (PVB19) and human herpesvirus 6 (HHV6) are increasingly found in endomyocardial biopsy samples. Methods and Results— Consequently, our aim was to evaluate the prevalence and clinical presentation of cardiac PVB19 and/or HHV6 infection in a cohort of myocarditis patients and to follow its clinical course. In addition, we sought to demonstrate patterns of myocardial damage and to determine predictors for chronic heart failure. Our study design consisted of a cardiovascular magnetic resonance protocol as well as endomyocardial biopsies in the myocardial region affected as indicated by cardiovascular magnetic resonance. One hundred twenty-eight patients were enrolled by clinical criteria. In the group of myocarditis patients (n=87), PVB19 (n=49), HHV6 (n=16), and combined PVB19/HHV6 infections (n=15) were detected most frequently. The remaining patients were diagnosed with healing myocarditis (n=15) or did not have myocarditis (n=26). Patients with PVB19 presented in a manner similar to that of myocardial infarction; most had typical subepicardial late gadolinium enhancement in the lateral wall and recovered within months. Conversely, patients with HHV6 and especially with HHV6/PVB19 myocarditis presented with new onset of heart failure, had septal late gadolinium enhancement, and frequently progressed toward chronic heart failure. Conclusions— Our data indicate that PVB19 and HHV6 are the most important causes for viral myocarditis in Germany and that the clinical presentation is related to the type of virus. Furthermore, clinical presentation, type of virus, and pattern of myocardial damage are related to the clinical course.

Myocardial scarring in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy

OBJECTIVESnWe sought to ascertain whether myocardial scarring occurs in living unselected patients with hypertrophic cardiomyopathy (HCM).nnnBACKGROUNDnMyocardial scarring is known to occur in select HCM patients, who were highly symptomatic prior to death or who died suddenly. The majority of HCM patients, however, are minimally symptomatic and have not suffered sudden death.nnnMETHODSnCine and gadolinium-enhanced magnetic resonance imaging was performed in 21 HCM patients who were predominantly asymptomatic. Gadolinium hyperenhancement was assumed to represent myocardial scar, and the extent of scar was compared to left ventricular (LV) morphology and function.nnnRESULTSnScarring was present in 17 patients (81%). Scarring occurred only in hypertrophied regions (> or =10 mm), was patchy with multiple foci, and predominantly involved the middle third of the ventricular wall. All 17 patients had scarring at the junction of the interventricular septum and the right ventricular (RV) free wall. On a regional basis, the extent of scarring correlated positively with wall thickness (r = 0.36, p < 0.0001), and inversely with wall thickening (r = -0.21, p < 0.0001). On a per patient basis, the extent of scarring (mean, 8 +/- 9% of LV mass) was minimally related to maximum wall thickness (r = 0.40, p = 0.07) and LV mass (r = 0.33, p = 0.15), and correlated inversely with ejection fraction (r = -0.46, p = 0.04).nnnCONCLUSIONSnMyocardial scarring is common in asymptomatic or mildly symptomatic HCM patients who have not suffered sudden death. When present, scarring occurs in hypertrophied regions, is consistently localized to the junctions of the septum and RV free wall, and correlates positively with regional hypertrophy and inversely with regional contraction.

Myocardial scar visualized by cardiovascular magnetic resonance imaging predicts major adverse events in patients with hypertrophic cardiomyopathy.

OBJECTIVESnWe sought to establish the prognostic value of a comprehensive cardiovascular magnetic resonance (CMR) examination in risk stratification of hypertrophic cardiomyopathy (HCM) patients.nnnBACKGROUNDnWith annual mortality rates ranging between 1% and 5%, depending on patient selection, a small but significant number of HCM patients are at risk for an adverse event. Therefore, the identification of and prophylactic therapy (i.e., defibrillator placement) in patients with HCM who are at risk of dying are imperative.nnnMETHODSnTwo-hundred forty-three consecutive patients with HCM were prospectively enrolled. All patients underwent initial CMR, and 220 were available for clinical follow-up. The mean follow-up time was 1,090 days after CMR. End points were all-cause and cardiac mortality.nnnRESULTSnDuring follow-up 20 of the 220 patients died, and 2 patients survived sudden cardiac death due to adequate implantable cardioverter-defibrillator discharge. Most events (n = 16) occurred for cardiac reasons; the remaining 6 events were related to cancer and accidents. Our data indicate that the presence of scar visualized by CMR yields an odds ratio of 5.47 for all-cause mortality and of 8.01 for cardiac mortality. This might be superior to classic clinical risk factors, because in our dataset the presence of 2 risk factors yields an odds ratio of 3.86 for all-cause and of 2.20 for cardiac mortality, respectively. Multivariable analysis also revealed the presence of late gadolinium enhancement as a good independent predictor of death in HCM patients.nnnCONCLUSIONSnAmong our population of largely low or asymptomatic HCM patients, the presence of scar indicated by CMR is a good independent predictor of all-cause and cardiac mortality.

Reproducibility of Chronic Infarct Size Measurement by Contrast-Enhanced Magnetic Resonance Imaging

Background—The reproducibility of contrast-enhanced MRI has not been established. We compared MRI reproducibility for infarct size determination with that of 99mTc-sestamibi (MIBI) single photon emission computed tomography (SPECT). Methods and Results—Patients with chronic myocardial infarction defined by enzymes (peak creatine kinase-MB 173±119 U/L) were scanned twice by MRI (MRI I and MRI II, n=20) and twice by SPECT (SPECT I and SPECT II, n=15) on the same day. The MRI contrast agent was injected during MRI I but not MRI II to test the effect of imaging time after contrast. Resting Tc-MIBI SPECT images were acquired and infarct size was determined with commercial software. Infarct size in patients scanned by MRI and SPECT was 14±6% of left ventricular mass (%LV) by MRI (range 4%LV to 27%LV) and 14±7%LV by SPECT (range 4%LV to 26%LV). MRI I and II scans were performed 10±2 and 27±3 minutes after contrast, respectively. For MRI, the difference in infarct size between scans I and II (bias) was −0.1%LV, and the coefficient of repeatability was ±2.4%LV. For SPECT, bias was −1.3%LV, and the coefficient of repeatability was ±4.0%LV. Within individual patients, no systematic differences in infarct size were detected when the 2 MRI scans were compared, the 2 SPECT scans were compared, or MRI was compared to SPECT. Conclusion—The size of healed infarcts measured by contrast-enhanced MRI does not change between 10 and 30 minutes after contrast. The clinical reproducibility of contrast-enhanced MRI for infarct size determination compares favorably with that of routine clinical SPECT.

Long-Term Follow-Up of Biopsy-Proven Viral Myocarditis Predictors of Mortality and Incomplete Recovery

OBJECTIVESnThis study sought to evaluate the long-term mortality in patients with viral myocarditis, and to establish the prognostic value of various clinical, functional, and cardiovascular magnetic resonance (CMR) parameters.nnnBACKGROUNDnLong-term mortality of viral myocarditis, as well as potential risk factors for poor clinical outcome, are widely unknown.nnnMETHODSnA total of 222 consecutive patients with biopsy-proven viral myocarditis and CMR were enrolled. A total of 203 patients were available for clinical follow-up, and 77 patients underwent additional follow-up CMR. The median follow-up was 4.7 years. Primary endpoints were all-cause mortality and cardiac mortality.nnnRESULTSnWe found a relevant long-term mortality in myocarditis patients (19.2% all cause, 15% cardiac, and 9.9% sudden cardiac death [SCD]). The presence of late gadolinium enhancement (LGE) yields a hazard ratio of 8.4 for all-cause mortality and 12.8 for cardiac mortality, independent of clinical symptoms. This is superior to parameters like left ventricular (LV) ejection fraction, LV end-diastolic volume, or New York Heart Association (NYHA) functional class, yielding hazard ratios between 1.0 and 3.2 for all-cause mortality and between 1.0 and 2.2 for cardiac mortality. No patient without LGE experienced SCD, even if the LV was enlarged and impaired. When focusing on the subgroup undergoing follow-up CMR, we found an initial NYHA functional class >I as the best independent predictor for incomplete recovery (p = 0.03).nnnCONCLUSIONSnAmong our population with a wide range of clinical symptoms, biopsy-proven viral myocarditis is associated with a long-term mortality of up to 19.2% in 4.7 years. In addition, the presence of LGE is the best independent predictor of all-cause mortality and of cardiac mortality. Furthermore, initial presentation with heart failure may be a good predictor of incomplete long-term recovery.

CMR imaging predicts death and other adverse events in suspected cardiac sarcoidosis.

OBJECTIVESnThis study aimed to demonstrate that the presence of late gadolinium enhancement (LGE) is a predictor of death and other adverse events in patients with suspected cardiac sarcoidosis.nnnBACKGROUNDnCardiac sarcoidosis is the most important cause of patient mortality in systemic sarcoidosis, yielding a 5-year mortality rate between 25% and 66% despite immunosuppressive treatment. Other groups have shown that LGE may hold promise in predicting future adverse events in this patient group.nnnMETHODSnWe included 155 consecutive patients with systemic sarcoidosis who underwent cardiac magnetic resonance (CMR) for workup of suspected cardiac sarcoid involvement. The median follow-up time was 2.6 years. Primary endpoints were death, aborted sudden cardiac death, and appropriate implantable cardioverter-defibrillator (ICD) discharge. Secondary endpoints were ventricular tachycardia (VT) and nonsustained VT.nnnRESULTSnLGE was present in 39 patients (25.5%). The presence of LGE yields a Cox hazard ratio (HR) of 31.6 for death, aborted sudden cardiac death, or appropriate ICD discharge, and of 33.9 for any event. This is superior to functional or clinical parameters such as left ventricular (LV) ejection fraction (EF), LV end-diastolic volume, or presentation as heart failure, yielding HRs between 0.99 (per % increase LVEF) and 1.004 (presentation as heart failure), and between 0.94 and 1.2 for potentially lethal or other adverse events, respectively. Except for 1 patient dying from pulmonary infection, no patient without LGE died or experienced any event during follow-up, even if the LV was enlarged and the LVEF severely impaired.nnnCONCLUSIONSnAmong our population of sarcoid patients with nonspecific symptoms, the presence of myocardial scar indicated by LGE was the best independent predictor of potentially lethal events, as well as other adverse events, yielding a Cox HR of 31.6 and of 33.9, respectively. These data support the necessity for future large, longitudinal follow-up studies to definitely establish LGE as an independent predictor of cardiac death in sarcoidosis, as well as to evaluate the incremental prognostic value of additional parameters.

EuroCMR (European Cardiovascular Magnetic Resonance) Registry: Results of the German Pilot Phase

OBJECTIVESnDuring its German pilot phase, the EuroCMR (European Cardiovascular Magnetic Resonance) registry sought to evaluate indications, image quality, safety, and impact on patient management of routine CMR.nnnBACKGROUNDnCMR has a broad range of applications and is increasingly used in clinical practice.nnnMETHODSnThis was a multicenter registry with consecutive enrollment of patients in 20 German centers.nnnRESULTSnA total of 11,040 consecutive patients were enrolled. Eighty-eight percent of patients received gadolinium-based contrast agents. Twenty-one percent underwent adenosine perfusion, and 11% high-dose dobutamine-stress CMR. The most important indications were workup of myocarditis/cardiomyopathies (32%), risk stratification in suspected coronary artery disease/ischemia (31%), as well as assessment of viability (15%). Image quality was good in 90.1%, moderate in 8.1%, and inadequate in 1.8% of cases. Severe complications occurred in 0.05%, and were all associated with stress testing. No patient died during or due to CMR. In nearly two-thirds of patients, CMR findings impacted patient management. Importantly, in 16% of cases the final diagnosis based on CMR was different from the diagnosis before CMR, leading to a complete change in management. In more than 86% of cases, CMR was capable of satisfying all imaging needs so that no further imaging was required.nnnCONCLUSIONSnCMR is frequently performed in clinical practice in many participating centers. The most important indications are workup of myocarditis/cardiomyopathies, risk stratification in suspected coronary artery disease/ischemia, and assessment of viability. CMR imaging as used in the centers of the pilot registry is a safe procedure, has diagnostic image quality in 98% of cases, and its results have strong impact on patient management.

European cardiovascular magnetic resonance (EuroCMR) registry – multi national results from 57 centers in 15 countries

BackgroundThe EuroCMR registry sought to evaluate indications, image quality, safety and impact on patient management of clinical routine CMR in a multi-national European setting. Furthermore, interim analysis of the specific protocols should underscore the prognostic potential of CMR.MethodsMulti-center registry with consecutive enrolment of patients in 57 centers in 15 countries. More than 27000 consecutive patients were enrolled.ResultsThe most important indications were risk stratification in suspected CAD/Ischemia (34.2%), workup of myocarditis/cardiomyopathies (32.2%), as well as assessment of viability (14.6%). Image quality was diagnostic in more than 98% of cases. Severe complications occurred in 0.026%, always associated with stress testing. No patient died during or due to CMR.u2009In 61.8% CMR findings impacted on patient management. Importantly, in nearly 8.7% the final diagnosis based on CMR was different to the diagnosis before CMR, leading to a complete change in management.u2009Interim analysis of suspected CAD and risk stratification in HCM specific protocols revealed a low rate of adverse events for suspected CAD patients with normal stress CMR (1.0% per year), and for HCM patients without LGE (2.7% per year).ConclusionThe most important indications in Europe are risk stratification in suspected CAD/Ischemia, work-up of myocarditis and cardiomyopathies, as well as assessment of viability. CMR imaging is a safe procedure, has diagnostic image quality in more than 98% of cases, and its results have strong impact on patient management. Interim analyses of the specific protocols underscore the prognostic value of clinical routine CMR in CAD and HCM.Condensed abstractThe EuroCMR registry sought to evaluate indications, image quality, safety and impact on patient management of clinical routine CMR in a multi-national European setting in a large number of cases (nu2009>u200927000). Based on our data CMR is frequently performed in European daily clinical routine. The most important indications in Europe are risk stratification in suspected CAD/Ischemia, work-up of myocarditis and cardiomyopathies, as well as assessment of viability. CMR imaging is a safe procedure, has diagnostic image quality in more than 98% of cases, and its results have strong impact on patient management. Interim analyses of the specific protocols underscore the prognostic value of clinical routine CMR in CAD and HCM.