Dobutamine cardiovascular magnetic resonance

Dobutamine stress cardiovascular magnetic resonance (CMR) is a new diagnostic tool for the noninvasive detection of coronary artery disease. With technological advances, CMR has evolved to become an adequate alternative to standard cardiac stress tests such as ECG exercise stress testing, stress echocardiography, and perfusion scintigraphy. Magnetic resonance imaging technology is widely available, possible in nearly every patient, and not associated with exposure to ionizing radiation. Its high reproducibility and high image quality of the anatomical features of the left ventricle and left ventricular function at rest and during stress make it an ideal technique for the comprehensive evaluation of patients with suspected coronary artery disease. Besides its ability to detect myocardial ischaemia, CMR has proved to be diagnostic for myocardial viability as well. A recent technical refinement in CMR using myocardial tagging has improved the diagnostic accuracy for myocardial ischaemia even further. This article reviews the pathophysiology and methodology of dobutamine stress CMR. The recent literature is discussed.</p

Dobutamine cardiovascular magnetic resonance

Dobutamine stress cardiovascular magnetic resonance (CMR) is a new diagnostic tool for the noninvasive detection of coronary artery disease. With technological advances, CMR has evolved to become an adequate alternative to standard cardiac stress tests such as ECG exercise stress testing, stress echocardiography, and perfusion scintigraphy. Magnetic resonance imaging technology is widely available, possible in nearly every patient, and not associated with exposure to ionizing radiation. Its high reproducibility and high image quality of the anatomical features of the left ventricle and left ventricular function at rest and during stress make it an ideal technique for the comprehensive evaluation of patients with suspected coronary artery disease. Besides its ability to detect myocardial ischaemia, CMR has proved to be diagnostic for myocardial viability as well. A recent technical refinement in CMR using myocardial tagging has improved the diagnostic accuracy for myocardial ischaemia even further. This article reviews the pathophysiology and methodology of dobutamine stress CMR. The recent literature is discussed.</p

The vascular nature of COVID-19

A potential link between mortality, D-dimer values and a prothrombotic syndrome has been reported in COVID-19 patients. The National Institute for Public Health of the Netherlands published a report for guidance on diagnosis, prevention and treatment of thromboembolic complications in COVID-19 with a new vascular disease concept. The analysis of all available current medical, laboratory and imaging data on COVID-19 confirms that symptoms and diagnostic tests can not be explained by impaired pulmonary ventilation. Further imaging and pathological investigations confirm that the COVID-19 syndrome is explained by perfusion disturbances first in the lung, but consecutively in all organs of the body. Damage of the microvasculature by SARS 1 and SARS 2 (COVID-19) viruses causes microthrombotic changes in the pulmonary capillaries and organs leading to macrothrombosis and emboli. Therefore anticoagulant profylaxis, close lab and CT imaging monitoring and early anticoagulant therapy are indicated

Early detection of heart function abnormality by native T1:a comparison of two T1 quantification methods

Objective To compare the robustness of native T1 mapping using mean and median pixel-wise quantification methods. Methods Fifty-seven consecutive patients without overt signs of heart failure were examined in clinical routine for suspicion of cardiomyopathy. MRI included the acquisition of native T1 maps by a motion-corrected modified Look-Locker inversion recovery sequence at 1.5 T. Heart function status according to four established volumetric left ventricular (LV) cardio MRI parameter thresholds was used for retrospective separation into subgroups of normal (n = 26) or abnormal heart function (n = 31). Statistical normality of pixel-wise T1 was tested on each myocardial segment and mean and median segmental T1 values were assessed. Results Segments with normally distributed pixel-wise T1 (57/58%) showed no difference between mean and median quantification in either patient group, while differences were highly significant (p <0.001) for the respective 43/42% non-normally distributed segments. Heart function differentiation between two patient groups was significant in 14 myocardial segments (p <0.001-0.040) by median quantification compared with six (p <0.001-0.042) by using the mean. The differences by median quantification were observed between the native T1 values of the three coronary artery territories of normal heart function patients (p = 0.023) and insignificantly in the abnormal patients (p = 0.053). Conclusion Median quantification increases the robustness of myocardial native T1 definition, regardless of statistical normality of the data. Compared with the currently prevailing method of mean quantification, differentiation between LV segments and coronary artery territories is better and allows for earlier detection of heart function impairment

Effects of Caffeine on Myocardial Blood Flow:A Systematic Review

Background. Caffeine is one of the most widely consumed stimulants worldwide. It is a well-recognized antagonist of adenosine and a potential cause of false-negative functional measurements during vasodilator myocardial perfusion. The aim of this systematic review is to summarize the evidence regarding the effects of caffeine intake on functional measurements of myocardial perfusion in patients with suspected coronary artery disease. Pubmed, Web of Science, and Embase were searched using a predefined electronic search strategy. Participantshealthy subjects or patients with known or suspected CAD. Comparisonsrecent caffeine intake versus no caffeine intake. Outcomesmeasurements of functional myocardial perfusion. Study designobservational. Fourteen studies were deemed eligible for this systematic review. There was a wide range of variability in study design with varying imaging modalities, vasodilator agents, serum concentrations of caffeine, and primary outcome measurements. The available data indicate a significant influence of recent caffeine intake on cardiac perfusion measurements during adenosine and dipyridamole induced hyperemia. These effects have the potential to affect the clinical decision making by re-classification to different risk-categories

Accurate late gadolinium enhancement prediction by early T1-based quantitative synthetic mapping

OBJECTIVES: Early synthetic gadolinium enhancement (ESGE) imaging from post-contrast T1 mapping after adenosine stress-perfusion cardiac magnetic resonance (CMR) was compared to conventional late gadolinium enhancement (LGE) imaging for assessing myocardial scar. METHODS: Two hundred fourteen consecutive patients suspected of myocardial ischaemia were referred for stress-perfusion CMR. Myocardial infarct volume was quantified on a per-subsegment basis in both synthetic (2-3 min post-gadolinium) and conventional (9 min post-gadolinium) images by two independent observers. Sensitivity, specificity, PPV and NPV were calculated on a per-patient and per-subsegment basis. RESULTS: Both techniques detected 39 gadolinium enhancement areas in 23 patients. The median amount of scar was 2.0 (1.0-3.1) g in ESGE imaging and 2.2 (1.1-3.1) g in LGE imaging (p=0.39). Excellent correlation (r=0.997) and agreement (mean absolute difference: -0.028±0.289 ml) were found between ESGE and LGE images. Sensitivity, specificity, PPV and NPV of ESGE imaging were 96 (78.9-99.9), 99 (97.1-100.0)%, 96 (76.5-99.4) and 99.5 (96.6-99.9) in patient-based and 99 (94.5-100.0), 100 (99.9-100.0)%, 97.0 (91.3-99.0) and 100.0 (99.8-100.0) in subsegment-based analysis. CONCLUSION: ESGE based on post-contrast T1 mapping after adenosine stress-perfusion CMR imaging shows excellent agreement with conventional LGE imaging for assessing myocardial scar, and can substantially shorten clinical acquisition time. KEY POINTS: • Synthetic gadolinium enhancement images can be used for detection of myocardial scar. • Early synthetic gadolinium enhancement images can substantially shorten clinical acquisition time. • ESGE has high diagnostic accuracy as compared to conventional late gadolinium enhancement. • Quantification of myocardial scar with ESGE closely correlates with conventional LGE. • ESGE after stress perfusion CMR avoids need for additional gadolinium administration

The additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress cardiac MRI for the detection of myocardial ischemia

Purpose of this study was to assess the additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress Cardiac-MR (CMR). Dobutamine Stress CMR was performed in 115 patients with an inconclusive diagnosis of myocardial ischemia on a 1.5 T system (Magnetom Avanto, Siemens Medical Systems). Three short-axis cine and grid series were acquired during rest and at increasing doses of dobutamine (maximum 40 μg/kg/min). On peak dose dobutamine followed immediately by a first pass myocardial perfusion imaging sequence. Images were graded according to the sixteen-segment model, on a four point scale. Ninety-seven patients showed no New (Induced) Wall Motion Abnormalities (NWMA). Perfusion imaging showed absence of perfusion deficits in 67 of these patients (69%). Perfusion deficits attributable to known previous myocardial infarction were found in 30 patients (31%). Eighteen patients had NWMA, indicative for myocardial ischemia, of which 14 (78%) could be confirmed by a corresponding perfusion deficit. Four patients (22%) with NWMA did not have perfusion deficits. In these four patients NWMA were caused by a Left Bundle Branch Block (LBBB). They were free from cardiac events during the follow-up period (median 13.5 months; range 6–20). Addition of first-pass myocardial perfusion imaging during peak-dose dobutamine stress CMR can help to decide whether a NWMA is caused by myocardial ischemia or is due to an (inducible) LBBB, hereby preventing a false positive wall motion interpretation

Prognostic value of the coronary artery calcium score in suspected coronary artery disease: a study of 644 symptomatic patients

Aim: The long-term value of coronary artery calcium (CAC) scanning has not been studied extensively in symptomatic patients, but was evaluated by us in 644 consecutive patients referred for stable chest pain. Methods: We excluded patients with a history of cardiovascular disease and with a CAC score of zero. CAC scanning was done with a 16-row MDCT scanner. Endpoints were: (a) overall mortality, (b) mortality or non-fatal myocardial infarction and (c) the composite of mortality, myocardial infarction or coronary revascularisation. Revascularisations within 1 year following CAC scanning were not considered. Results: The mean age of the 320 women and 324 men was 63 years. Follow-up was over 8 years. There were 58 mortalities, while 22 patients suffered non-fatal myocardial infarction and 24 underwent coronary revascularisation, providing 104 combined endpoints. Cumulative 8‑year survival was 95% with CAC score 100 and 100 and ≥400 units was 2.6 [95% confidence interval (CI) 1.23–5.54], and 4.6 (95% CI 2.1–9.47) respectively. After correction for clinical risk factors, CAC score remained independently associated with increased risk of cardiac events. Conclusions: Risk increased with increasing CAC score. Patients with CAC >100 or ≥400 Agatston units were at increased risk of major adverse cardiac events and are eligible for preventive measures. CAC scanning provided incremental prognostic information to guide the choice of diagnostic and therapeutic options in many subjects evaluated for chest pain