Preoperative cardiac screening using NT-proBNP in obese patients 50 years and older undergoing bariatric surgery: a study of 310 consecutive patients.

BACKGROUND: Obesity is associated with cardiovascular (CV) risk factors and diseases. Because bariatric surgery is increasingly performed in relatively elderly patients, a risk for pre- and postoperative CV complications exists. OBJECTIVES: We aimed to assess the value of plasma N-terminal-probrain natriuretic peptide (NT-proBNP) as a CV screening tool. SETTING: High-volume bariatric center. METHODS: Between June 2019 and January 2020, all consecutive bariatric patients 50 years and older underwent preoperative NT-proBNP assessment in this cohort study to screen for CV disease. Patients with elevated NT-proBNP (≥125 pg/mL) were referred for further cardiac evaluation, including electrocardiography and echocardiography. RESULTS: We included 310 consecutive patients (median age, 56 years; 79% female; body mass index = 43±6.5 kg/m2). A history of CV disease was present in 21% of patients, mainly atrial fibrillation (7%) and coronary artery disease (10%). A total of 72 patients (23%) had elevated NT-proBNP levels, and 67 of them underwent further cardiac workup. Of these 67 patients, electrocardiography (ECG) showed atrial fibrillation in 7 patients (10%). On echocardiography, 3 patients had left ventricular ejection fraction (LVEF) <40%, 9 patients had LVEF 40%-49%, and 13 patients had LVEF ≥50% with structural and/or functional remodeling. In 2 patients, elevated NT-proBNP prompted workup leading to a diagnosis of coronary artery disease and consequent percutaneous coronary intervention in 1 patient. CONCLUSIONS: Elevated NT-proBNP levels are present in 23% of patients 50 years and older undergoing bariatric surgery. In 37% of them, there was echocardiographic evidence for structural and/or functional remodeling. Further studies are needed to assess if these preliminary results warrant routine application of NT-proBNP to identify patients at risk for CV complications after bariatric surgery.

Acute to chronic pain transition in extremity trauma: A narrative review for future preventive interventions (part 2).

BACKGROUND: The first part of this series of 2 articles revealed that chronic pain is an important issue post extremity trauma (ET) involving permanent biological transformations. Interventions aimed at preventing chronic pain in ET patients are therefore required. OBJECTIVE: To conduct a comprehensive analysis of literature on risk and protective factors for chronic pain post-ET to guide the development of relevant preventive interventions. METHODS: A narrative review of the literature was undertaken. Databases were searched to identify studies on chronic pain prognostic factors in ET patients. RESULTS: Demographic, injury-related and psychological factors were shown to either contribute to or limit acute to chronic pain transition. High-intensity acute pain hasconsistently been identified as an important chronic pain risk factor. Other significant documented risk factors include: female gender, older age, less than college education, lower limb injury, symptoms of anxiety and depression and pain catastrophizing. Pain self-efficacy and pain acceptance have been shown to protect individuals against chronic pain. CONCLUSIONS: This narrative review highlights factors placing ET patients at higher risk of chronic pain or protecting them against this problem. Determining how these factors could be addressed in preventive interventions is the next step before undertaking their development.

Acute to chronic pain transition in extremity trauma: A narrative review for future preventive interventions (part 1).

BACKGROUND: Several studies have been conducted over the last decade that describe the issue of pain and prognostic factors of acute to chronic pain transition post extremity trauma (ET). However, no thorough interventions to prevent chronic pain development in ET patients have yet been proposed. OBJECTIVES: This first part of a series of two articles aimed to provide a comprehensive analysis of literature on the epidemiology of pain post-ET, the impact of persistent pain on ET patients and the relevant biological transformations involved in acute to chronic pain transition. The second article will focus on risk and protective factors relating to chronic pain that could potentially assist in the development of preventive interventions. METHODS: A narrative review of the literature was undertaken. Databases were searched to identify relevant studies and seminal works on the topics of interest. RESULTS: The review revealed that acute pain converts to chronic pain in up to 86% of ET patients. Analysis of study findings also indicated that chronic pain interferes with activities of daily living and capacity to work. Weak associations between chronic pain and anxiety as well as depression have been demonstrated. Anxiety and depression have been identified as important predictors of chronic pain post-ET. Neuro-immunological transformations, genetics and an emotional shift in the brain circuitry involved in nociception have been shown to contribute to the transition towards chronic pain. CONCLUSIONS: This narrative review supports the view that acute to chronic pain transition is a prevalent and significant issue post-ET. It also provides information about patients who present a higher risk of chronic pain and features that should be integrated in preventive interventions as well as methodological considerations pertaining to the evaluation of such interventions.

Rehabilitation after lower limb injury: development of a predictive score (RALLI score).

BACKGROUND: The purpose of our study was to identify the risk factors associated with the need for inpatient rehabilitation after lower limb injury to develop a predictive scoring tool for early identification of such patients. METHODS: We followed a prospective cohort of patients admitted to a level 1 trauma centre. Data were collected through chart review and a self-administered questionnaire on sociodemographics, patient living environment, pretrauma status, injury and treatment received. We compared patients who were discharged home with those going to rehabilitation after acute care. Analysis consisted of bivariate comparisons and logistic regression. RESULTS: Our study included 160 patients with a mean age of 56 years. A total of 40% were discharged to an inpatient rehabilitation centre. Factors associated with inpatient rehabilitation were low preinjury physical health status, concomitant injury of the upper limbs, bilateral lower limb injury, the use of a walking aid before injury, head injury and femur or pelvic fractures. We created a predictive score using the top 3 risk factors: upper limb injury, bilateral lower limb injury and presence of femoral or pelvic fractures. The chance of needing inpatient rehabilitation rose from 14% with 0 factors to 47% with 1 factor and 96% with 2 factors. CONCLUSION: Rehabilitation planning should begin for patients exhibiting at least of 3 risk factors at the time of admission to acute care. Prospective validation of the tool is needed, but it has the potential to orient the multidisciplinary team's decision on rehabilitation needs postdischarge.

CONTEXTE: Notre étude avait pour but de recenser les facteurs de risque associés à un séjour en établissement de réadaptation pour les patients victimes de traumatismes aux membres inférieurs, afin de concevoir un outil de classification prédictive pour l'identification précoce de ces patients. MÉTHODES: Nous avons suivi une cohorte prospective de patients admis dans un centre de traumatologie de niveau 1. Les données proviennent d'une revue des dossiers et de questionnaires auto-administrés sur les caractéristiques sociodémographiques, le milieu de vie des patients, leur statut prémorbide, le traumatisme subi et le traitement reçu. Nous avons comparé les patients qui ont reçu leur congé pour retourner à la maison à ceux qui devaient faire un séjour en centre de réadaptation après des soins actifs. L'analyse a reposé sur des comparaisons bivariées et la régression logistique. RÉSULTATS: Notre étude a regroupé 160 patients âgés en moyenne de 56 ans. En tout, 40 % ont été transférés dans des centres de réadaptation où ils ont séjourné. Les facteurs associés au transfert dans un centre de réadaptation étaient : piètre état de santé physique avant le traumatisme, traumatisme concomitant aux membres supérieurs, traumatisme aux 2 membres inférieurs, utilisation d'un dispositif d'aide à la marche avant le traumatisme, traumatisme crânien et fractures du fémur ou du bassin. Nous avons créé un score prédictif sur la base des 3 principaux facteurs, soit traumatisme concomitant aux membres supérieurs, traumatisme aux 2 membres inférieurs et fractures du fémur ou du bassin. Le risque de devoir séjourner en centre de réadaptation est passé de 14 % en l'absence de ces facteurs à 47 % en présence de l'un des facteurs et à 96 % en présence de 2 facteurs. CONCLUSION: La planification de la réadaptation devrait commencer dès leur admission en centre de soins actifs pour les patients qui présentent au départ au moins 3 facteurs de risque. Il faudra valider l'outil de façon prospective, mais il pourrait orienter les décisions de l'équipe multidisciplinaire quant aux besoins de réadaptation lorsque le patient reçoit son congé.

Using drug response data to identify molecular effectors, and molecular "omic" data to identify candidate drugs in cancer.

The current convergence of molecular and pharmacological data provides unprecedented opportunities to gain insights into the relationships between the two types of data. Multiple forms of large-scale molecular data, including but not limited to gene and microRNA transcript expression, DNA somatic and germline variations from next-generation DNA and RNA sequencing, and DNA copy number from array comparative genomic hybridization are all potentially informative when one attempts to recognize the panoply of potentially influential events both for cancer progression and therapeutic outcome. Concurrently, there has also been a substantial expansion of the pharmacological data being accrued in a systematic fashion. For cancer cell lines, the National Cancer Institute cell line panel (NCI-60), the Cancer Cell Line Encyclopedia (CCLE), and the collaborative Genomics of Drug Sensitivity in Cancer (GDSC) databases all provide subsets of these forms of data. For the patient-derived data, The Cancer Genome Atlas (TCGA) provides analogous forms of genomic information along with treatment histories. Integration of these data in turn relies on the fields of statistics and statistical learning. Multiple algorithmic approaches may be chosen, depending on the data being considered, and the nature of the question being asked. Combining these algorithms with prior biological knowledge, the results of molecular biological studies, and the consideration of genes as pathways or functional groups provides both the challenge and the potential of the field. The ultimate goal is to provide a paradigm shift in the way that drugs are selected to provide a more targeted and efficacious outcome for the patient.

Atherosclerotic renal artery stenosis is prevalent in cardiorenal patients but not associated with left ventricular function and myocardial fibrosis as assessed by cardiac magnetic resonance imaging.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is common in cardiovascular diseases and associated with hypertension, renal dysfunction and/or heart failure. There is a paucity of data about the prevalence and the role of ARAS in the pathophysiology of combined chronic heart failure (CHF) and chronic kidney disease (CKD). We investigated the prevalence in patients with combined CHF/CKD and its association with renal function, cardiac dysfunction and the presence and extent of myocardial fibrosis. METHODS: The EPOCARES study (ClinTrialsNCT00356733) investigates the role of erythropoietin in anaemic patients with combined CHF/CKD. Eligible subjects underwent combined cardiac magnetic resonance imaging (cMRI), including late gadolinium enhancement, with magnetic resonance angiography of the renal arteries (MRA). RESULTS: MR study was performed in 37 patients (median age 74 years, eGFR 37.4 ± 15.6 ml/min, left ventricular ejection fraction (LVEF) 43.3 ± 11.2%), of which 21 (56.8%) had ARAS (defined as stenosis >50%). Of these 21 subjects, 8 (21.6%) had more severe ARAS >70% and 8 (21.6%) had a bilateral ARAS >50% (or previous bilateral PTA). There were no differences in age, NT-proBNP levels and medication profile between patients with ARAS versus those without. Renal function declined with the severity of ARAS (p = 0.03), although this was not significantly different between patients with ARAS versus those without. Diabetes mellitus was more prevalent in patients without ARAS (56.3%) against those with ARAS (23.8%) (p = 0.04). The presence and extent of late gadolinium enhancement, depicting myocardial fibrosis, did not differ (p = 0.80), nor did end diastolic volume (p = 0.60), left ventricular mass index (p = 0.11) or LVEF (p = 0.15). Neither was there a difference in the presence of an ischemic pattern of late enhancement in patients with ARAS versus those without. CONCLUSIONS: ARAS is prevalent in combined CHF/CKD and its severity is associated with a decline in renal function. However, its presence does not correlate with a worse LVEF, a higher left ventricular mass or with the presence and extent of myocardial fibrosis. Further research is required for the role of ARAS in the pathophysiology of combined chronic heart and renal failure.

Control of upper limb prostheses: terminology and proportional myoelectric control-a review.

The recent introduction of novel multifunction hands as well as new control paradigms increase the demand for advanced prosthetic control systems. In this context, an unambiguous terminology and a good understanding of the nature of the control problem is important for efficient research and communication concerning the subject. Thus, one purpose of this paper is to suggest an unambiguous taxonomy, applicable to control systems for upper limb prostheses and also to prostheses in general. A functionally partitioned model of the prosthesis control problem is also presented along with the taxonomy. In the second half of the paper, the suggested taxonomy has been exploited in a comprehensive literature review on proportional myoelectric control of upper limb prostheses. The review revealed that the methods for system training have not matured at the same pace as the novel multifunction prostheses and more advanced intent interpretation methods. Few publications exist regarding the choice of training method and the composition of the training data set. In this context, the notion of outcome measures is essential. By definition, system training involves optimization, and the quality of the results depends heavily on the choice of appropriate optimization criteria. In order to further promote the development of proportional myoelectric control, these topics need to be addressed.

Progressive osteolysis of the radius after distal biceps tendon repair with the bioabsorbable screw.

BACKGROUND: Several complications have been reported with the use of the PLLA (poly-L-Lactide) bioabsorbable screw in orthopedic surgery. The hypothesis was that the use of a bioabsorbable screw in distal biceps tenodesis results in significant osteolysis of the radial bone. The correlation between osteolysis and functional and clinical outcomes was also studied. METHODS: All consecutive patients who underwent anatomic repair of the distal biceps tendon with a bioabsorbable screw were included. From the x-ray taken immediately after the surgery, the ratio between the volume of the bone tunnel and the volume of the radius bone section was measured. This relation was calculated at different follow-up periods to obtain the percentage of tunnel enlargement over time. Complications, as well as functional and clinical outcomes, were also assessed. Mayo Elbow Performance Score (MEPS), the quick-Disability Arm Shoulder Hand (DASH), and the Short-Form 12 (SF-12) were used. RESULTS: Nineteen consecutive patients were available for follow-up. The average initial relative volume occupied by the screw tunnel was 49% of the bone section and increased to 61% at the last follow-up at an average of 22 months (range, 3-62 months). Eight of the 19 patients presented postoperative complications. There was only 1 case of complete bone filling of the tunnel, which was observed at a 5-year and 2-months follow-up. There was no significant correlation between the volume of bone resorption and functional and clinical outcomes. DISCUSSION: No correlation was found between the volume of bone tunnel and the functional outcome. However, the results indicate that the use of a bioabsorbable screw in distal biceps tendon repair results in significant bone osteolysis.

RedundancyMiner: De-replication of redundant GO categories in microarray and proteomics analysis.

BACKGROUND: The Gene Ontology (GO) Consortium organizes genes into hierarchical categories based on biological process, molecular function and subcellular localization. Tools such as GoMiner can leverage GO to perform ontological analysis of microarray and proteomics studies, typically generating a list of significant functional categories. Two or more of the categories are often redundant, in the sense that identical or nearly-identical sets of genes map to the categories. The redundancy might typically inflate the report of significant categories by a factor of three-fold, create an illusion of an overly long list of significant categories, and obscure the relevant biological interpretation. RESULTS: We now introduce a new resource, RedundancyMiner, that de-replicates the redundant and nearly-redundant GO categories that had been determined by first running GoMiner. The main algorithm of RedundancyMiner, MultiClust, performs a novel form of cluster analysis in which a GO category might belong to several category clusters. Each category cluster follows a "complete linkage" paradigm. The metric is a similarity measure that captures the overlap in gene mapping between pairs of categories. CONCLUSIONS: RedundancyMiner effectively eliminated redundancies from a set of GO categories. For illustration, we have applied it to the clarification of the results arising from two current studies: (1) assessment of the gene expression profiles obtained by laser capture microdissection (LCM) of serial cryosections of the retina at the site of final optic fissure closure in the mouse embryos at specific embryonic stages, and (2) analysis of a conceptual data set obtained by examining a list of genes deemed to be "kinetochore" genes.

Staphylococcus aureus pericardial abscess presenting as a localized bulge of the heart contour.

Purulent pericarditis usually presents as an acute illness with diffuse involvement of the whole pericardium, but can rarely present as a localized effusion. Here, we present a patient with a pericardial abscess caused by Staphylococcus aureus. After surgical drainage of the abscess, the patient made a good recovery. To the best of our knowledge, this is the first case of a pericardial abscess presenting as a localized bulge of the heart contour on the chest X-ray.

Multifactorial regulation of E-cadherin expression: an integrative study.

E-cadherin (E-cad) is an adhesion molecule associated with tumor invasion and metastasis. Its down-regulation is associated with poor prognosis for many epithelial tumor types. We have profiled E-cad in the NCI-60 cancer cell lines at the DNA, RNA, and protein levels using six different microarray platforms plus bisulfite sequencing. Here we consider the effects on E-cad expression of eight potential regulatory factors: E-cad promoter DNA methylation, the transcript levels of six transcriptional repressors (SNAI1, SNAI2, TCF3, TCF8, TWIST1, and ZFHX1B), and E-cad DNA copy number. Combined bioinformatic and pharmacological analyses indicate the following ranking of influence on E-cad expression: (1) E-cad promoter methylation appears predominant, is strongly correlated with E-cad expression, and shows a 20% to 30% threshold above which E-cad expression is silenced; (2) TCF8 expression levels correlate with (-0.62) and predict (P < 0.00001) E-cad expression; (3) SNAI2 and ZFHX1B expression levels correlate positively with each other (+0.83) and also correlate with (-0.32 and -0.30, respectively) and predict (P = 0.03 and 0.01, respectively) E-cad expression; (4) TWIST1 correlates with (-0.34) but does not predict E-cad expression; and (5) SNAI1 expression, TCF3 expression, and E-cad DNA copy number do not correlate with or predict E-cad expression. Predictions of E-cad regulation based on the above factors were tested and verified by demethylation studies using 5-aza-2'-deoxycytidine treatment; siRNA knock-down of TCF8, SNAI2, or ZFHX1B expression; and combined treatment with 5-aza-2'-deoxycytidine and TCF8 siRNA. Finally, levels of cellular E-cad expression are associated with levels of cell-cell adhesion and response to drug treatment.

Elective versus urgent laparoscopic appendectomy for complicated appendicitis.

AIM: Urgent appendectomy in patients with acute appendicitis (AA) complicated by abscess or phlegmon is associated with a high rate of complications. Recent developments in CT scanning have allowed patients with complicated appendicitis to be better identified. We choose to treat these patients with initial antibiotic therapy followed by elective appendectomy. We reported the results of this strategy and compared it with urgent appendectomy. METHODS: A retrospective analysis of patients diagnosed with complicated acute appendicitis (CAA) between 1998 and 2007 treated either by urgent appendectomy or with antibiotic therapy and elective appendectomy was performed. We assessed the efficacy of antibiotic therapy for CAA. We compared the postoperative course between urgent and elective appendectomy. RESULTS: We treated 56 patients with CAA: 40 by urgent appendectomy and 16 by antibiotics. All 16 patients improved with no need for urgent surgery, with 15 undergoing elective appendectomy. Postoperative complications were significantly lower in the elective group. Conversion rate and mean operative time were also lower but not significantly different. However, the duration of total hospital stay, antibiotic therapy and sick leave were higher. CONCLUSIONS: Initial antibiotic therapy followed by elective appendectomy may be proposed in patients diagnosed with CAA.

The additive prognostic value of perfusion and functional data assessed by quantitative gated SPECT in women.

BACKGROUND: The aim of this study was to assess the prognostic value of technetium-99m tetrofosmin gated SPECT imaging in women using quantitative gated single photon emission computed tomography (SPECT) imaging. METHODS: We followed 453 consecutive female patients. Average follow-up was 1.33 years (max. 2.55). Hard endpoints were cardiac death, acute myocardial infarction, or documented ventricular fibrillation. Event-free survival curves were obtained. Optimal cutoff values for left ventricular (LV) volumes, LV ejection fraction (LVEF), and perfusion data to predict outcome were determined by ROC curve analysis. RESULTS: A total of 236 patients had an abnormal study, of whom 27 patients experienced hard events (16 deaths) and 47 patients soft events. For hard events summed stress score (SSS) and LVEF, and for any cardiac event SSS showed independent incremental prognostic value. The survival curves were maximally separated when using cutoff values for SSS of > or = 22 and LVEF < 52% (P < 0.001, HR 4.61 and P < 0.001 HR 5.24 for SSS and LVEF resp.), and SSS > or = 14 (P < 0.001 HR 3.76) for any cardiac event. CONCLUSION: In women, perfusion and functional parameters derived from quantitative gated technetium-99m tetrofosmin SPECT imaging can adequately be used for cardiac risk assessment. Using quantitative gated SPECT, female patients with an LVEF < 52% or an SSS > or = 22 are at increased risk for subsequent hard events. Furthermore, patients with an SSS > or = 14 are at increased risk for any cardiac events.

The dumb ErbB receptor helps healing.

ErbB3 receptor is a member of the epidermal growth factor (EGF) receptor (ErbB1) family. Okwueze et al. have transfected this receptor in a pig model of wounds and demonstrate that it accelerates the resurfacing of the wounds when combined with epiregulin or heparin-binding EGF. Currently, only hypotheses can be proposed to explain the observations.

Detailed DNA methylation profiles of the E-cadherin promoter in the NCI-60 cancer cells.

E-cadherin (E-cad) is a transmembrane adhesion glycoprotein, the expression of which is often reduced in invasive or metastatic tumors. To assess E-cad's distribution among different types of cancer cells, we used bisulfite-sequencing for detailed, base-by-base measurement of CpG methylation in E-cad's promoter region in the NCI-60 cell lines. The mean methylation levels of the cell lines were distributed bimodally, with values pushed toward either the high or low end of the methylation scale. The 38 epithelial cell lines showed substantially lower (28%) mean methylation levels compared with the nonepithelial cell lines (58%). The CpG site at -143 with respect to the transcriptional start was commonly methylated at intermediate levels, even in cell lines with low overall DNA methylation. We also profiled the NCI-60 cell lines using Affymetrix U133 microarrays and found E-cad expression to be correlated with E-cad methylation at highly statistically significant levels. Above a threshold of approximately 20% to 30% mean methylation, the expression of E-cad was effectively silenced. Overall, this study provides a type of detailed analysis of methylation that can also be applied to other cancer-related genes. As has been shown in recent years, DNA methylation status can serve as a biomarker for use in choosing therapy.

Prognostic value of gated SPECT in patients with left bundle branch block.

BACKGROUND: The aim of this study was to assess the prognostic value of quantitative gated technetium 99m tetrofosmin single photon emission computed tomography (SPECT) imaging in patients with left bundle branch block (LBBB). METHODS AND RESULTS: We followed up 101 consecutive patients with LBBB using Tc-99m tetrofosmin gated SPECT imaging. The mean follow-up was 1.24 years (maximum, 2.48 years). Hard endpoints were all-cause death and acute myocardial infarction. Event-free survival curves were obtained. Optimal cutoff points for left ventricular (LV) volumes and LV ejection fraction (EF) to predict outcome were determined by receiver operating characteristic curve analysis. Of the patients, 94 had an abnormal study. Fifteen hard events occurred (thirteen deaths). Perfusion abnormalities were similar for patients with or without events. For LV function parameters, the survival curves were maximally separated when we used cutoff values of 160 mL or greater for end-diastolic volume (P = .019 and hazard ratio [HR] of 1.04 for hard events, P = .024 and HR of 1.04 for all-cause death), 100 mL or greater for end-systolic volume (P = .043 and HR of 1.04 for hard events, P = .062 and HR of 1.04 for all-cause death), and lower than 35% for LVEF (P = .013 and HR of 0.81 for hard events, P = .047 and HR of 0.81 for all-cause death). CONCLUSION: By use of quantitative gated SPECT imaging, LBBB patients with an end-diastolic volume of 160 mL or greater, end-systolic volume of 100 mL or greater, or LVEF lower than 35% are at increased risk for subsequent cardiac events.

Effects of acetylation, polymerase phosphorylation, and DNA unwinding in glucocorticoid receptor transactivation.

Varying the concentration of selected factors alters the induction properties of steroid receptors by changing the position of the dose-response curve (or the value for half-maximal induction=EC(50)) and the amount of partial agonist activity of antisteroids. We now describe a rudimentary mathematical model that predicts a simple Michaelis-Menten curve for the multi-step process of steroid-regulated gene induction. This model suggests that steps far downstream from receptor binding to steroid can influence the EC(50) of agonist-complexes and partial agonist activity of antagonist-complexes. We therefore asked whether inhibitors of three possible downstream steps can reverse the effects of increased concentrations of two factors: glucocorticoid receptors (GRs) and Ubc9. The downstream steps (with inhibitors in parentheses) are protein deacetylation (TSA and VPA), DNA unwinding (CPT), and CTD phosphorylation of RNA polymerase II (DRB and H8). None of the inhibitors mimic or prevent the effects of added GRs. However, inhibitors of DNA unwinding and CTD phosphorylation do reverse the effects of Ubc9 with high GR concentrations. These results support our earlier conclusion that different rate-limiting steps operate at low and high GR concentrations versus high GR with Ubc9. The present data also suggest that downstream steps can modulate the EC(50) of GR-mediated induction, thus both supporting the utility of our mathematical model and widening the field of biochemical processes that can modify the EC(50).

Evaluation of the Quantitative Gated SPECT (QGS) software program in the presence of large perfusion defects.

OBJECTIVES: To evaluate the reproducibility and operator dependence for the quantitative regional left ventricular functional parameters (LVFP) assessed by Cedars-Sinai's Quantitative automated gated SPECT (QGS) software. METHODS: The QGS algorithm was reviewed in detail and potential operator dependencies were defined. Series of prototypes were selected, consisting of (a) normal perfusion, (b) perfusion defects in all perfusion regions, (c) perfusion studies of patients with angiographic confirmed normal coronary arteries, proximal (>or=70% stenoses) single and multiple vessel disease, and (d) spurious activity in close proximity. While defining and re-orienting the volume containing the left ventricle, the operator adjusted 8 variables/degrees of freedom (DF). The software was used without further operator interventions. Results were expressed as a coefficient of variation (COV). Separate COV were calculated per distinct DF. A segment was considered not robust when the COV did exceed 20% in a single DF, 15% in at least 2 DF, or 10% in at least 3 DF. RESULTS: Regional left ventricular EF and volumes showed excellent reproducibility. Normal perfusion and the vessel disease prototypes showed an excellent COV (for all re-orientation steps [33/prototype]) mostly below 5% for LVFP. However, regional wall motion and thickening became less reliable in the presence of large perfusion defects or artifacts. CONCLUSIONS: Quantitative estimates for regional left ventricular functional data show excellent reproducibility using automated gated SPECT. However, there may be substantial operator dependency in the presence of large defects or spurious activity in close proximity.

Pulmonary embolism: prospective comparison of iso-osmolar and low-osmolarity nonionic contrast agents for contrast enhancement at CT angiography.

PURPOSE: To prospectively evaluate contrast enhancement on pulmonary computed tomographic (CT) angiograms obtained by using an iso-osmolar versus a low-osmolarity contrast agent to exclude pulmonary embolism. MATERIALS AND METHODS: Written patient consent was obtained on a form approved by the institutional review board, and the board approved the study. This prospective, randomized, double-blinded clinical trial included 47 patients referred for multi-detector row CT angiography to exclude pulmonary embolism over a 5-month period. Patients received either iohexol or iodixanol as an intravenous contrast agent. Three radiologists independently evaluated enhancement homogeneity and quality in designated pulmonary artery branches at four consecutive levels in the lower lobe of the left lung from lobar to subsegmental arteries. This evaluation was performed at a workstation separately for homogeneity and quality with two different three-level scales established with consensus. Percentages of each given score were compared with the chi2 test. The mean attenuation (expressed in Hounsfield units) for each contrast agent was compared with Student t test, and interobserver agreement (kappa value) was calculated. RESULTS: The percentages of arteries graded as excellent or not diagnostic were not statistically different (P >.05), with comparison of the two contrast agents at all levels. The intensity of enhancement (quantitative evaluation of enhancement by using mean attenuation of vessel lumen) was similar (P >.05) in the two groups. The kappa values varied from 0.35 to 0.56 among readers. CONCLUSION: Use of an iso-osmolar contrast agent at multi-detector row CT angiography to exclude pulmonary embolism did not significantly improve enhancement quality when this feature was compared with that of a low-osmolarity contrast agent.