Heart lung axis in acute pulmonary embolism: Role of CT in risk stratification.

Pulmonary embolism (PE) remains a significant cause of mortality requiring prompt diagnosis and risk stratification. This review focuses on the role of computed tomography (CT) in the risk stratification of acute PE, highlighting its impact on patient management. We will explore basic pathophysiology of pulmonary embolism (PE) and review current guidelines, which will help radiologists interpret images within a broader clinical context.

The Application of Conditional Probability to Harmonize Nuclear Cardiology Test Results.

Both exercise single photon emission computed tomography (SPECT) imaging and myocardial perfusion imaging with positron emission tomography produce multiple outcome variables. These include the stress electrocardiogram (ECG), visual perfusion assessment and quantitative myocardial blood flow. Bayes' analysis using conditional probability allows the distillation of multiple test results into a single probability of disease for individual patients.

The chest pain guidelines revisited: cherry picking from the frequentist tree.

The new chest pain guideline document was recently released. The biggest changes are in the recommendations for intermediate and high-risk patients with known and unknown CAD. Coronary CT angiography has been recommended as the preferred imaging test for patients < 65 years old with chest pain.

Harmonizing multimodality imaging results using Bayesian analysis: the case of CT coronary angiography and CT-derived fractional flow reserve.

Coronary computed tomographic angiography (CCTA) may provide both anatomic and CT fractional flow reserve data (CTFFR). The objective is to use Bayesian analysis to develop a model wherein the probability of significant coronary artery disease (CAD) by CTFFR can be determined given the prior probability (P) of the combined clinical and CCTA result. 172 patients referred for CCTA and subsequently underwent coronary angiography were automatically referred to CTFFR analysis.

High dose intracoronary N-acetylcysteine in a porcine model of ST-elevation myocardial infarction.

We sought to evaluate the safety and efficacy of N-acetylcysteine (NAC) on ischemia and reperfusion in a pig model focusing on cardio-renal protection. High doses of NAC may provide protection from contrast induced nephropathy (CIN). NAC has also been demonstrated to reduce myocardial infarction size and improve left ventricular function after ischemia in both humans and animals studies.

Myocardial perfusion imaging with first-pass computed tomographic imaging: Measurement of coronary flow reserve in an animal model of regional hyperemia.

Background: The accurate assessment of myocardial blood flow (MBF) is a potential adjunct to the anatomy of CT coronary angiography.

Purpose: To compare semi-quantitative parameters from first-pass CT (FP CT) imaging with absolute measures of MBF in an animal model of altered MBF.

Methods: A pig model of intracoronary adenosine (n = 8) was used during FP CT.

Accuracy of cardiac magnetic resonance of absolute myocardial blood flow with a high-field system: comparison with conventional field strength.

Objectives: The aim of this study was to determine the accuracy of cardiac magnetic resonance (CMR) first pass (FP) perfusion measures of absolute myocardial blood flow (MBF) with a 3.0-T magnet and compare these measures with FP perfusion at 1.5-T with absolute MBF by labeled microspheres as the gold standard.

Estimation of absolute myocardial blood flow during first-pass MR perfusion imaging using a dual-bolus injection technique: comparison to single-bolus injection method.

Purpose: To compare the dual-bolus to single-bolus quantitative first-pass magnetic resonance myocardial perfusion imaging for estimation of absolute myocardial blood flow (MBF).

Materials And Methods: Dogs had local hyperemia of MBF in the left anterior descending (LAD) coronary artery (intracoronary adenosine). Animals (n = 6) had sequential single- and dual-bolus perfusion studies with microsphere determination of absolute MBF.

Gated SPECT imaging to detect changes in myocardial blood flow during progressive coronary occlusion.

Background: The ability to track dynamic changes in myocardial blood flow (MBF) and wall motion with serial gated perfusion imaging may be a limiting factor in assessing new therapies. The purpose of this study was to determine whether gated Tc-99 m sestamibi (MIBI) SPECT imaging can track small changes in MBF in a model of progressive ischemia.

Methods: Eight pigs (20 kg) underwent lateral thoracotomy for placement of an ameroid constrictor on the left circumflex coronary artery (LCX) and indwelling femoral and left atrial catheters for serial microsphere determinations of absolute MBF.

Imaging and quantifying valvular heart disease using magnetic resonance techniques.

Echocardiography remains the cornerstone of noninvasive valvular heart disease evaluation. There are instances where MRI can be of use. Aside from the obvious advantage where limited acoustic windows are present, cardiac magnetic resonance (CMR) allows for imaging in any desired plane, and advantage can be taken of the ability to align with any regurgitant or stenotic flow jet.

Determining myocardial viability in chronic ischemic left ventricular dysfunction: a prospective comparison of rest-redistribution thallium 201 single-photon emission computed tomography, nitroglycerin-dobutamine echocardiography, and intracoronary myocardial contrast echocardiography.

Background: Detection of viable myocardium (VM) has important therapeutic implications for chronic ischemic left ventricular (LV) systolic dysfunction. We compared the ability of nitroglycerin-dobutamine echocardiography (NTG-DE), intracoronary myocardial contrast echocardiography (MCE), and rest-redistribution thallium 201 single-photon emission computed tomography (RRT-SPECT) to detect VM in this setting.

Methods: Patients with LV ejection fraction (LVEF) <40% and multivessel coronary disease suitable for revascularization underwent NTG-DE, MCE, RRT-SPECT, and radionuclide ventriculography to determine baseline LVEF.

Myocardial tagging and strain analysis at 3 Tesla: comparison with 1.5 Tesla imaging.

Purpose: To determine whether imaging at 3 T could improve and prolong the tag contrast compared to images acquired at 1.5 T in normal volunteers, and whether such improvement would translate into the ability to perform strain measurements in diastole.

Materials And Methods: Normal volunteers (N = 13) were scanned at 1.

Grade 3 ischemia on the admission electrocardiogram predicts rapid progression of necrosis over time and less myocardial salvage by primary angioplasty.

Background: Among patients with ST-elevation acute myocardial infarction, those with terminal QRS distortion (grade 3 ischemia) have higher mortality and larger infarct size (IS) than patients without QRS distortion (grade 2 ischemia).

Methods: We assessed the relation of baseline electrocardiographic ischemia grades to area at risk (AR) and myocardial salvage [100 (AR-IS)/AR] in 79 patients who underwent primary angioplasty for first ST-elevation acute myocardial infarction and had technetium Tc 99m sestamibi single-photon emission computed tomography before angioplasty (AR) and at predischarge (IS). Patients were classified as having grade 2 ischemia (ST elevation without terminal QRS distortion in any of the leads, n = 48), grade 2.

Manganese enhanced magnetic resonance imaging of normal and ischemic canine heart.

The ability of MnCl2 to enhance canine myocardium and to delineate ischemic areas is demonstrated. A dose-response curve was measured using T1 weighted images in 11 dogs. MnCl2 (36, 113, 360, and 3600 micromol) was infused over a period of 3 min.

3 Tesla MR imaging provides improved contrast in first-pass myocardial perfusion imaging over a range of gadolinium doses.

Purpose: To compare myocardial enhancement during first-pass myocardial perfusion imaging at 3.0 Tesla (T) and 1.5T.

Comparison between human and automated electrocardiographic waveform measurements for calculating the Anderson-Wilkins acuteness score in patients with acute myocardial infarction.

The Anderson-Wilkins (AW) electrocardiographic (ECG) acuteness score complements time from pain onset in prognostic stratification of patients with acute myocardial infarction (AMI). However, for the AW acuteness score to be of practical use in the acute situation, it must be an integral component of a commercial automated ECG analysis program. The objective of this study was to determine the concordance between human and computer measurements and calculation of the AW acuteness score.