Clinical implications of compromised Rb PET data acquisition.

Background: We wished to document the prevalence and quantitative effects of compromised Rb PET data acquisitions on myocardial flow reserve (MFR).

Methods And Results: Data were analyzed retrospectively for 246 rest and regadenoson-stress studies of 123 patients evaluated for known or suspected CAD. An automated injector delivered pre-determined activities of Rb.

Early onset of left ventricular regional asynchrony in arteries with sub-clinical stenosis.

Background: Asynchrony has been reported to be a marker of ischemic-induced left ventricular dysfunction, the magnitude of which correlates with extent of epicardial coronary disease. We wished to determine whether normal-appearing arterial territories with mild degrees of asynchrony have lower Rb PET absolute myocardial blood flow (MBF) and/or lower myocardial flow reserve (MFR).

Methods And Results: Data were examined retrospectively for 105 patients evaluated for known/suspected CAD who underwent rest/regadenoson-stress Rb PET/CT and quantitative coronary angiography.

Vessel-specific quantification of absolute myocardial blood flow, myocardial flow reserve and relative flow reserve by means of fused dynamic NH PET and CCTA: Ranges in a low-risk population and abnormality criteria.

Objectives: The goal of the present work is to present a novel methodology for the extraction of MBF, MFR and RFR along coronary arteries by means of multimodality image fusion of dynamic PET and CCTA images.

Background: FFR is the reference standard to identify flow-limiting lesions, but its invasiveness limits broad application. New noninvasive methodologies are warranted to stratify patients and guide treatment.

Relationship of Rb PET territorial myocardial asynchrony to arterial stenosis.

Objective: Rb PET/CT rest/regadenoson-stress data enable quantification of left ventricular rest and stress function, perfusion, and asynchrony. Our study was conducted to determine which parameters best identify patients with multi-vessel disease (MVD) and individual stenosed arteries.

Methods: PET/CT data were reviewed retrospectively for 105 patients referred for evaluation of CAD, who also underwent angiography.

Motion Correction and Its Impact on Absolute Myocardial Blood Flow Measures with PET.

Purpose Of Review: Motion artifacts, due to cardiac and respiratory cycles, myocardial cardiac creep, or gross patient movements, have been extensively investigated in the context of relative myocardial perfusion imaging with SPECT and PET. These movements have been identified as a major source of errors in image quantification and diagnosis. Recently, as dynamic PET quantification for myocardial blood flow assessment has entered clinical practice, similar questions have arisen on the impact of motion on final blood flow values.

Technical aspects of acquiring and measuring myocardial blood flow: Method, technique, and QA.

Measuring absolute myocardial blood flow (MBF) is becoming a common aid for diagnosing patients suspected to have coronary artery disease. An MBF study, however, requires a scanner with high count rate capability, is more susceptible to artifacts, and is much more technically involved than static imaging, which leads to a greater risk of artifactual results contaminating the final result. This technical note gives the reader an introductory understanding of the method for calculating MBF.

Compartmental modeling of [(11)C]MENET binding to the norepinephrine transporter in the healthy human brain.

Introduction: Dysregulation of the noradrenergic system has been implicated in a number of neurological conditions such as Parkinson's and Alzheimer's. [(11)C]MENET is a novel PET radiotracer with high affinity and selectivity for the norepinephrine transporter. The applicability of different kinetic models on [(11)C]MENET PET image quantification in healthy population is evaluated.

Quantitative outcome of registration methods for correcting cardiac drift in cardiac PET/CT imaging.

Myocardial perfusion studies suffer from artifacts caused by misalignment of the transmission and emission data due to the influences of voluntary and involuntary patient motion. Regardless of 68Ge or respiratory-averaged CT based attenuation correction and good patient cooperation, approximately 21% of perfusion studies exhibit artifacts arising from misalignment that cannot be corrected by manipulating the attenuation acquisition protocol. This misalignment, termed cardiac drift, is caused by slow-moving abdominal cavity contents that reposition the heart in the thorax and appear as myocardial uptake overlying the left CT lung in fused PET/CT images.

Patient Preferences Regarding Colorectal Cancer Screening: Test Features and Cost Willing to Pay Out of Pocket.

The purpose of this investigation was to evaluate whether test features would make an individual more or less likely to undergo colorectal cancer screening and how much an individual would be willing to pay out of pocket for a screening test. The methods include an administration of a survey to consecutive adult patients of a general medicine clinic. The survey consisted of Likert-scale questions assessing the patients' likelihood of choosing a screening test based on various test characteristics.

Colorectal Cancer Initial Diagnosis: Screening Colonoscopy, Diagnostic Colonoscopy, or Emergent Surgery, and Tumor Stage and Size at Initial Presentation.

Introduction/background: Rates of colorectal cancer screening are improving but remain suboptimal. Limited information is available regarding how patients are diagnosed with colorectal cancer (for example, asymptomatic screened patients or diagnostic workup because of the presence of symptoms). The purpose of this investigation was to determine how patients were diagnosed with colorectal cancer (screening colonoscopy, diagnostic colonoscopy, or emergent surgery) and tumor stage and size at diagnosis.

Relationships between left ventricular asynchrony and myocardial blood flow.

Objective: Rb PET protocols enable determination of left ventricular asynchrony (LVAS) at rest and stress, along with myocardial blood flow (MBF). We hypothesized that in patients with resting LVAS, MBF differs between those with stress-induced LVAS improvement and those with stress-induced LVAS deterioration.

Methods: We retrospectively analyzed Rb rest/regadenoson stress PET studies of 195 patients evaluated for known or suspected coronary artery disease.

Long-Term Consequences of Early Trauma on Coronary Heart Disease: Role of Familial Factors.

Early childhood trauma has been associated with increased risk for subsequent coronary heart disease (CHD), but little is known regarding what role genetic and shared familial factors play in this relationship. Early trauma was measured retrospectively in 562 male middle-aged twins with the Early Trauma Inventory. CHD was assessed by history and by myocardial perfusion imaging with positron emission tomography [(13)N] ammonia.

Research Resources Survey: Radiology Junior Faculty Development.

Rationale And Objectives: To assess resources available to junior faculty in US academic radiology departments for research mentorship and funding opportunities and to determine if certain resources are more common in successful programs.

Materials And Methods: An anonymous survey covering scientific environment and research mentorship and was sent to vice-chairs of research of radiology departments. Results were evaluated to identify practices of research programs with respect to mentorship, resources, and opportunities.

Magnetic resonance imaging of rectal cancer: staging and restaging evaluation.

Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning.

Optimal section thickness for detection of polyps at MR: resolution phantom study.

Purpose: To determine (1) the sensitivity for detection of small polyps with varying MR slice thicknesses using a resolution phantom; (2) reader confidence in polyp detection; and (3) image acquisition time.

Methods: A resolution phantom was created using a 3D printer. Polyp morphologies were sessile (height = diameter), flat (height = 1/2 diameter of the base), and pedunculated (stalk length = polyp diameter).

Endothelial Dysfunction is Associated with Occult Coronary Artery Disease Detected by Positron Emission Tomography.

Objective: Silent myocardial ischemia is common in asymptomatic subjects without a prior history of coronary artery disease (CAD) and is associated with increased morbidity and mortality. Our objective was to determine whether endothelial dysfunction is associated with silent myocardial ischemia and whether the association is independent of genetic and familial factors.

Material And Methods: We examined 416 male monozygotic and dizygotic twins aged 47 to 63 years, free of symptomatic CAD.

Quantification of dopamine transporter density with [18F]FECNT PET in healthy humans.

Introduction: Fluorine-18 labeled 2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-fluoroethyl)nortropane ([(18)F]FECNT) binds reversibly to the dopamine transporter (DAT) with high selectivity. [(18)F]FECNT has been used extensively in the quantification of DAT occupancy in non-human primate brain and can distinguish between Parkinson's and healthy controls in humans. The purpose of this work was to develop a compartment model to characterize the kinetics of [(18)F]FECNT for quantification of DAT density in healthy human brain.

Accuracy Evaluation of a 3D Ultrasound-guided Biopsy System.

Early detection of prostate cancer is critical in maximizing the probability of successful treatment. Current systematic biopsy approach takes 12 or more randomly distributed core tissue samples within the prostate and can have a high potential, especially with early disease, for a false negative diagnosis. The purpose of this study is to determine the accuracy of a 3D ultrasound-guided biopsy system.

The relationship between ischemia-induced left ventricular dysfunction, coronary flow reserve, and coronary steal on regadenoson stress-gated (82)Rb PET myocardial perfusion imaging.

Background: Gated rubidium-82 ((82)Rb) positron emission tomography (PET) imaging studies are acquired both at rest and during pharmacologic stress. Stress-induced ischemic left ventricular dysfunction (LVD) can produce a significant decrease in left ventricular ejection fraction (LVEF) from rest to stress. We determined the prevalence on PET of stress LVD with reduced ejection fraction (EF) and its association with absolute global and regional coronary flow reserve (CFR), and with relative perfusion defect summed difference score (SDS).

Differences in neural activation for object-directed grasping in chimpanzees and humans.

The human faculty for object-mediated action, including tool use and imitation, exceeds that of even our closest primate relatives and is a key foundation of human cognitive and cultural uniqueness. In humans and macaques, observing object-directed grasping actions activates a network of frontal, parietal, and occipitotemporal brain regions, but differences in human and macaque activation suggest that this system has been a focus of selection in the primate lineage. To study the evolution of this system, we performed functional neuroimaging in humans' closest living relatives, chimpanzees.

Tissue-type plasminogen activator mediates neuronal detection and adaptation to metabolic stress.

Adenosine monophosphate-activated protein kinase (AMPK) is an energy sensor that regulates cellular adaptation to metabolic stress. Tissue-type plasminogen activator (tPA) is a serine proteinase found in the intravascular space, where its main role is as thrombolytic enzyme, and in neurons, where its function is less well understood. Here, we report that glucose deprivation induces the mobilization and package of neuronal tPA into presynaptic vesicles.

Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

Objectives: The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD.

Background: It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited.

Methods: We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry.