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Biomedical subjects

Joan M Lacomis

Publications and source records attributed to Joan M Lacomis.

12 recordsLinked to original sources
PubMed2006

A novel two-dimensional echocardiographic image analysis system using artificial intelligence-learned pattern recognition for rapid automated ejection fraction.

OBJECTIVES: We sought to test the hypothesis that a novel 2-dimensional echocardiographic image analysis system using artificial intelligence-learned pattern recognition can rapidly and reproducibly calculate ejection fraction (EF). BACKGROUND: Echocardiographic EF by manual tracing is time consuming, and visual assessment is inherently subjective. METHODS: We studied 218 patients (72 female), including 165 with abnormal left ventricular (LV) function. Auto EF incorporated a database trained on >10,000 human EF tracings to automatically locate and track the LV endocardium from routine grayscale digital cineloops and calculate EF in 15 s. Auto EF results were independently compared with manually traced biplane Simpson's rule, visual EF, and magnetic resonance imaging (MRI) in a subset. RESULTS: Auto EF was possible in 200 (92%) of consecutive patients, of which 77% were completely automated and 23% required manual editing. Auto EF correlated well with manual EF (r = 0.98; 6% limits of agreement) and required less time per patient (48 +/- 26 s vs. 102 +/- 21 s; p < 0.01). Auto EF correlated well with visual EF by expert readers (r = 0.96; p < 0.001), but interobserver variability was greater (3.4 +/- 2.9% vs. 9.8 +/- 5.7%, respectively; p < 0.001). Visual EF was less accurate by novice readers (r = 0.82; 19% limits of agreement) and improved with trainee-operated Auto EF (r = 0.96; 7% limits of agreement). Auto EF also correlated with MRI EF (n = 21) (r = 0.95; 12% limits of agreement), but underestimated absolute volumes (r = 0.95; bias of -36 +/- 27 ml overall). CONCLUSIONS: Auto EF can automatically calculate EF similarly to results by manual biplane Simpson's rule and MRI, with less variability than visual EF, and has clinical potential.

Aged↗
PubMed2006

Direct comparison of computed tomography and magnetic resonance imaging for characterization of posterior left atrial morphology.

OBJECTIVE: Accumulating evidence points to the central importance of the posterior left atrium (PLA) for atrial fibrillation (AF). Catheter ablation intended to cure AF is increasingly practiced; performance and assessment of this procedure is enhanced by accurate imaging of PLA anatomy. Prior reports have suggested that both computed tomographic (CT) and magnetic resonance (MR) imaging techniques provide accurate PLA images. These techniques have never been compared directly. MATERIALS AND METHODS: Twenty patients referred for catheter ablation underwent preoperative imaging using both CT and MR. Each technique was used to create a multidimensional image of the PLA. RESULTS: Within patients, morphologic and dimensional PLA indices, including number of individual pulmonary venoatrial junctions, presence of ostial branches, circumference of each venoatrial junction, venoatrial junction "non-circularity", and distance between ipsilateral superior and inferior venoatrial junctions, were well correlated. CONCLUSIONS: CT and MR-based images of the PLA appear comparable. Technique selection should involve considerations of toxicity, tolerance, and local resources.

Adult↗
PubMed2005

Revised curriculum on cardiothoracic radiology for diagnostic radiology residency with goals and objectives related to general competencies.

This document is a revision of a previously published cardiothoracic curriculum for diagnostic radiology residency, and reflects interval changes in the clinical practice of cardiothoracic radiology and changes in the Accreditation Council for Graduate Medical Education (ACGME) requirements for diagnostic radiology training programs. The revised ACGME Program Requirements for Residency Education in Diagnostic Radiology went into effect December 2003.

Clinical Competence↗
PubMed2005

3D-multidetector CT angiography in the evaluation of potential donors for living donor lung transplantation.

INTRODUCTION: In living donor lung transplant, donor lobectomies from 2 donors provide right and left lower lobes for transplantation. In the past, routine evaluation of pulmonary anatomy was not performed preoperatively. Intraoperatively, surgeons were often forced to sacrifice the lingular artery or right middle lobe segmental artery to obtain an adequate arterial cuff for safe reimplantation. This study was performed to evaluate the utility of preoperative 3D-multidetector CT angiography (3D-MDCTA) as a noninvasive method of assessing pulmonary arteries to improve donor selection and surgical planning for living lung donors. SUBJECTS AND METHODS: Five potential lung donors for 2 recipients were included in the study. CT scanning with 4 channel multidetector-row CT was performed, using a modified pulmonary embolism protocol. Post-processing was performed using volume rendering techniques on a commercially available workstation. RESULTS: 3D-MDCT demonstrated that there are a number of variations in pulmonary arterial anatomy and that ideal anatomy was seldom encountered. Comparison of different donors determined which lower lobes were most favorable for transplantation. Surgery confirmed the accuracy of 3D-MDCTA. There were no pulmonary arterial complications, and no vessels were sacrificed. CONCLUSION: Safely explanting lower lobes from living donors for lung transplantation poses challenges not encountered in harvesting cadaveric donors or performing lobectomies for malignancy. 3D-MDCTA of pulmonary arteries can noninvasively delineate the often-complex pulmonary anatomy, which may assist in donor selection as well as reduce donor intraoperative and postoperative vascular complications.

Adult↗
PubMed2005

Incidental finding on MDCT of patent ductus arteriosus: use of CT and MRI to assess clinical importance.

OBJECTIVE: The purpose of this article is to describe the imaging features of patent ductus arteriosus (PDA) identified on chest MDCT performed for other indications and to describe the additional functional information that cardiac MRI can provide about these lesions. CONCLUSION: The daily use of MDCT studies for the evaluation of pulmonary embolic disease or aortic abnormalities can reveal incidental PDAs. Small incidental PDAs can be identified on chest MDCT angiography timed for either the pulmonary arteries or the aorta. Using multiplanar reformations, one can assess PDA location, caliber, length, and presence of calcifications. The presence of a "positive" or a "negative contrast jet" verifies a patent shunt. Cardiac MRI shows the detailed anatomic and morphologic features of a PDA. Hemodynamic information revealing the presence and severity of a significant shunt is obtainable using velocity-encoded MRI, allowing accurate shunt calculation. Using MDCT and MRI, information regarding the clinical significance of an incidental PDA can influence management decisions. The imaging information was used to determine that one PDA required intervention.

Aged↗
PubMed2004

Diagnosis of pulmonary embolism by acute right heart morphologic and hemodynamic changes observed during exercise stress echocardiography.

In addition to the conventional means of diagnosing pulmonary embolism, resting echocardiography has sometimes been useful. We describe the case of a patient with a normal resting transthoracic echocardiogram, but with a markedly abnormal posttreadmill exercise echocardiogram revealing acute right ventricular dilatation, marked ventricular septal shift, and acute pulmonary hypertension. Pulmonary embolism was suspected and subsequently confirmed by chest computed tomographic angiography.

Acute Disease↗
PubMed2003

Prevalence effect in a laboratory environment.

PURPOSE: To measure observer performance at various levels of prevalence. MATERIALS AND METHODS: A multiobserver multiabnormality receiver operating characteristic (ROC) study to assess the effect of prevalence on observer performance was conducted. Fourteen observers, including eight faculty members, two fellows, and four residents, interpreted 1,632 posteroanterior chest images with five prevalence levels by using a nested study design. Performance comparisons were accomplished by using a multireader multicase approach to assess the effect of prevalence from 28% (69 of 249) to 2% (31 of 1,577) on diagnostic accuracy. The mean times required to review and report a case were analyzed and compared for different levels of prevalence and readers' experience. RESULTS: Area under the ROC curve demonstrated that, with the study experimental conditions, no significant effect could be measured as a function of prevalence (P >.05) for any abnormality, group of cases, or readers. There were no significant differences (P >.05) in the mean times required to review and report cases at different prevalence levels and with different groups of readers. CONCLUSION: The consistency in the results and the size of this study suggest that with laboratory conditions, if a prevalence effect exists, it is quite small in magnitude; hence, it will not likely alter conclusions derived from such studies.

Laboratories↗
PubMed2003

Multi-detector row CT of the left atrium and pulmonary veins before radio-frequency catheter ablation for atrial fibrillation.

Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins and posterior left atrium is increasingly being used to treat recurrent or refractory atrial fibrillation that resists pharmacologic therapy or cardioversion. Successful RFCA of atrial fibrillation requires resolution of abnormal rhythms while minimizing complications and can be achieved with precise, preprocedural, three-dimensional (3D) anatomic delineation of the target, the atriopulmonary venous junction. Three-dimensional multi-detector row computed tomography (CT) of the pulmonary veins and left atrium provides the necessary anatomic information for successful RFCA, including (a) the number, location, and angulation of pulmonary veins and their ostial branches unobscured by adjacent cardiac and vascular anatomy, and (b) left atrial volume. The 3D multi-detector row CT scanning and postprocessing techniques used for pre-RFCA planning are straightforward. Radiologists must not only understand these techniques but must also be familiar with atrial fibrillation and the technical considerations and complications associated with RFCA of this condition. In addition, radiologists must be familiar with anatomic variants of the left atrium and distal pulmonary veins and understand the importance of these variants to the referring cardiac interventional electrophysiologist.

Atrial Fibrillation↗
PubMed2002

Radiologists' performance in the diagnosis of liver tumors with central scars by using specific CT criteria.

PURPOSE: To determine the performance of radiologists with differing levels of expertise in the diagnosis of the most common types of liver tumors with central scars (ie, focal nodular hyperplasia [FNH], fibrolamellar hepatocellular carcinoma [HCC], and large hepatic hemangioma) by using specific computed tomographic (CT) findings. MATERIALS AND METHODS: Review of medical records at the University of Pittsburgh Medical Center identified patients with a total of 64 liver tumors that had central scars-including 29 cases of FNH, 20 fibrolamellar HCCs, and 15 large (>3.5 cm in diameter) hemangiomas-and with CT scans available for review. Retrospective review of these scans was performed individually by six radiologists who were blinded to the diagnosis, including two faculty abdominal radiologists, one abdominal imaging fellow, and three radiology residents. Individual performance was evaluated by means of receiver operating characteristic analysis, and interobserver agreement was measured by using the Cronbach alpha. Individual CT findings that may allow differentiation of tumor types were identified with the Kruskal-Wallis test. RESULTS: CT allowed good to excellent interobserver agreement in the diagnosis of tumor type and in recognition of differential findings among the three types. The individual accuracy of diagnosis was very good, with the average area under the receiver operating characteristic curve ranging from 0.81 to 0.90. Although the faculty radiologists performed the best, the differences in performance between the subgroups of readers and the levels of confidence in diagnosis were not statistically significant. The diagnosis of fibrolamellar HCC was the most accurate and had the highest sensitivity, followed by FNH and large hemangioma. Clinical and CT findings that were found to be statistically significant in differentiating tumor types were patient age and sex, tumor size larger than 10 cm, width of tumor scars, invasion of vessels, nodular centripetal enhancement, marked hyperattenuation on arterial phase images, lymphadenopathy, heterogeneity, extrahepatic metastases, surface lobulation, calcification, and isoattenuation with liver tissue on portal venous phase images. CONCLUSION: CT allows accurate differentiation of the most common types of liver tumors with central scars, including FNH, fibrolamellar HCC, and large hemangioma.

Adolescent↗
PubMedDate not supplied

Myocardial bridging: noninvasive diagnosis with multidetector CT.

An epicardial segment of a coronary artery that courses through the myocardium is termed "myocardial bridging". Generally, this is a benign condition but it may lead to angina, ischemia or infarction. The current diagnostic standard of reference is coronary catheter angiography. Intravascular ultrasound (IVUS) and intracoronary Doppler (ICD) have been recently introduced as well. These are all invasive imaging modalities. We describe the utilization of gated multidetector CT (MDCT) as a non-invasive alternative for diagnosis of this anomaly. Information regarding the tunneled coronary artery including its length, depth, precise location and surrounding myocardium is easily obtainable.

Contrast Media↗