PubMed Health⌕ Search

Biomedical subjects

James H Thrall

Publications and source records attributed to James H Thrall.

At least 19 recordsLinked to original sources
PubMed2005

Using imaging biomarkers to accelerate drug development and clinical trials.

There is increasing evidence that human medical imaging can help answer key questions that arise during the drug development process. Imaging modalities such as magnetic resonance imaging, computed tomography and positron emission tomography can offer significant insights into the bioactivity, pharmacokinetics and dosing of drugs, in addition to supporting registration applications. In this review, examples from oncology, neurology, psychiatry, infectious diseases and inflammatory diseases are used to illustrate the role imaging can play. We conclude with some remarks concerning new developments that will be required to significantly advance the field of pharmaco-imaging.

Animals↗
PubMed2005

Imaging angiogenesis: applications and potential for drug development.

Recognition of the importance of angiogenesis to tumor growth and metastasis has led to efforts to develop new drugs that are targeted to angiogenic vasculature. Clinical trials of these agents are challenging, both because there is no agreed upon method of establishing the correct dosage for drugs whose mechanism of action is not primarily cytotoxic and because of the long time it takes to determine whether such drugs have a clinical effect. Therefore, there is a need for rapid and effective biomarkers to establish drug dosage and monitor clinical response. This review addresses the potential of imaging as a way to accurately and reliably assess changes in angiogenic vasculature in response to therapy. We describe the advantages and disadvantages of several imaging modalities, including positron emission tomography, x-ray computed tomography, magnetic resonance imaging, ultrasound, and optical imaging, for imaging angiogenic vasculature. We also discuss the analytic methods used to derive blood flow, blood volume, empirical semiquantitative hemodynamic parameters, and quantitative hemodynamic parameters from pharmacokinetic modeling. We examine the validity of these methods, citing studies that test correlations between data derived from imaging and data derived from other established methods, their reproducibility, and correlations between imaging-derived hemodynamic parameters and other pathologic indicators, such as microvessel density, pathology score, and disease outcome. Finally, we discuss which imaging methods are most likely to have the sensitivity and reliability required for monitoring responses to cancer therapy and describe ways in which imaging has been used in clinical trials to date.

Angiogenesis Inhibitors↗
PubMed2005

Multidetector-row CT: economics and workflow.

With rapid evolution of multidetector-row CT (MDCT) technology and applications, several factors such as technology upgrade and turf battles for sharing cost and profitability affect MDCT workflow and economics. MDCT workflow optimization can enhance productivity and reduce unit costs as well as increase profitability, in spite of decrease in reimbursement rates. Strategies for workflow management include standardization, automation, and constant assessment of various steps involved in MDCT operations. In this review article, we describe issues related to MDCT economics and workflow.

Economics, Medical↗
PubMed2005

Small incidental pulmonary nodules: how useful is short-term interval CT follow-up?

PURPOSE: To determine whether short-term (<6 month) follow-up imaging by thoracic CT is necessary to evaluate small (< or =4 mm) noncalcified nodules (NCN) in patients with no history of malignancy or acute lung disease. MATERIALS AND METHODS: We reviewed serial thoracic helical CT scans between 1999-2000 obtained for the evaluation or follow-up imaging of small NCNs. CT scans were performed at 5-mm collimation. Patients were excluded if they had a history of neoplasm, infection, pulmonary fibrosis, or immune deficiency; also excluded if nodule(s) > or =5 mm at intake, or no follow-up scan within 1 year. NCNs were evaluated for number, size, configuration, and change in size over time. Exact 95% Confidence Intervals were used to estimate chances of nodule growth in 3-, 6-, and 12- month intervals. RESULTS: A total of 1826 patients received a CT for NCNs. Four hundred fourteen patients met inclusion criteria (221 women, 193 men; mean age, 65.6 years). Eighty-five patients had a single NCN, 329 had multiple NCNs. One hundred seventy-three patients had additional > or =5 mm nodules. One hundred twenty-seven patients were lost to follow up within the 1-year period. Eight nodules cleared. None of the < or =4 mm NCNs grew on follow-up imaging within 12 months. Three patients developed lung cancer in other nodules > or =5 mm (5-10 mm). These nodules grew on follow up intervals of 3-13 months. One patient had a 19 mm benign hamartoma that grew in 9 months. The calculated chance that a NCN < or =4 mm will grow within 3, 6, and 12 months (95% CI) is < or =0.89%, 1.01%, and 1.28%, respectively. CONCLUSION: The chance of growth in < or =4 mm NCNs in a 3- to 6-month period in patients with no previous history of malignancy or immune disorder is small; therefore, short-term follow-up imaging (<12 month) for nodules < or =4 mm is not necessary.

Adult↗
PubMed2005

The business of PET/CT.

OBJECTIVE: This chapter discusses how to market to and educate the referral community and third party payers about the benefits of the emerging PET/CT technology. CONCLUSION: Clearly, the fusion of PET and CT into one piece of equipment will present challenges for years to come. It is important for providers to be involved with all of the administrators, managers, referring and interpreting physicians, and the payer communities in their market to clearly understand individual payer business practices and to identify opportunities to educate and influence changes in payment and coverage policies.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed2004

Application of recently developed computer algorithm for automatic classification of unstructured radiology reports: validation study.

PURPOSE: To validate the accuracy of Lexicon Mediated Entropy Reduction (LEXIMER), a new information theory-based computer algorithm developed by the authors for independent analysis and classification of unstructured radiology reports based on the presence of clinically important findings (F(T), where (T) represents "true") and recommendations for subsequent action (R(T)). MATERIALS AND METHODS: The study was approved by the Human Research Committee of the institutional review board. Consecutive de-identified radiology reports (n = 1059) comprising results of barium studies (n = 99), computed tomography (n = 107), mammography (n = 90), magnetic resonance imaging (n = 108), nuclear medicine (n = 99), positron emission tomography (n = 106), radiography (n = 212), ultrasonography (n = 131), and vascular procedures (n = 107) were independently analyzed by two radiologists and then with LEXIMER to categorize the reports into F(T) and F(T)0 (containing or not containing clinically important findings) categories and R(T) and R(T)0 (containing or not containing recommendations for subsequent action) categories. Accuracy, sensitivity, specificity, and positive and negative predictive values of LEXIMER for placing reports into F(T) and F(T)0 and R(T) and R(T)0 categories were assessed by using appropriate statistical tests. RESULTS: There was strong interobserver concordance between the two radiologists for placing radiology reports into F(T) and R(T) categories (kappa = 0.9, P < .01). For the LEXIMER program, accuracy, sensitivity, specificity, and positive and negative predictive values, respectively, were 97.5% (95% confidence interval [CI]: 96.6%, 98.5%), 98.9% (95% CI: 97.9%, 99.6%), 94.9% (95% CI: 93.1%, 96.0%), 97.5% (95% CI: 96.6%, 98.0%), and 97.7% (95% CI: 95.8%, 98.8%) for placing radiology reports into F(T) and F(T)0 categories and 99.6% (95% CI: 99.2%, 99.9%), 98.2% (95% CI: 95.0%, 99.6%), 99.9% (95% CI: 99.4%, 99.99%), 99.4% (95% CI: 96.3%, 99.9%), and 99.7% (95% CI: 98.9%, 99.9%) for placing reports into R(T) and R(T)0 categories. CONCLUSION: LEXIMER is an accurate automated engine for evaluating the percentage positivity of clinically important findings and rates of recommendation for subsequent action in unstructured radiology reports.

Algorithms↗
PubMed2004

Trends in thoracic radiology over a decade at a large academic medical center.

OBJECTIVE: To investigate thoracic radiology usage over and above the secular trends associated with hospital-wide changes in the number of patients over a decade. MATERIALS AND METHODS: We retrospectively reviewed administrative data from our 905-bed tertiary-care hospital between January 1, 1992, to December 31, 2001. Three points of entry to the radiology department were identified: inpatient (IP), outpatient (OP), and the emergency room (ER). The total numbers of patients, imaging studies, chest radiographs, chest CTs, CTs for pulmonary embolism, pulmonary angiograms, ventilation/perfusion scintigrams (V/Qs), lung biopsies, cardiac and chest MRIs, and FDG-PET scans for lung nodules and masses were collected. The significance of trends using linear regression analysis was evaluated. RESULTS: IP and OP numbers have significantly increased over a decade (P = 0.04 and P = 0.01 respectively); ER patient numbers have not. There has been an increase in the ratio of chest radiographs per patient arising from the ER area (P = 0.0002). All 3 areas demonstrated an increase in the ratio of chest CTs per patient: IP (P = 0.0002), OP (P = <0.0001), and ER (P = <0.0001). IP and ER areas demonstrated an increase in the ratio of CTs for pulmonary embolism per patient (P = 0.006, P = 0.04 respectively). There was a decrease in the ratios of pulmonary angiograms and V/Qs per IP (P = 0.02 & P = 0.0003 respectively). Cardiac MRIs per patient demonstrated an increase (IP P = 0.01, OP P = 0.02). FDG-PET for lung nodules and masses per patient demonstrated an increase in IP (P = 0.03) and OP (P = 0.003) areas. The total number of chest imaging studies divided by the total number of imaging studies demonstrated an increase in IP and ER areas (P = 0.02 and P = 0.02 respectively). CONCLUSION: There has been an increase in thoracic radiology usage above secular trends, particularly in the regions of chest CT and FDG-PET. CT is replacing more traditional techniques to diagnose pulmonary embolism for inpatients.

Academic Medical Centers↗
PubMed2004

Enhancing research in academic radiology departments: recommendations of the 2003 Consensus Conference.

Opportunities for funded radiologic research are greater than ever, and the amount of federal funding coming to academic radiology departments is increasing. Even so, many medical school-based radiology departments have little or no research funding. Accordingly, a consensus panel was convened to discuss ways to enhance research productivity and broaden the base of research strength in as many academic radiology departments as possible. The consensus panel included radiologists who have leadership roles in some of the best-funded research departments, radiologists who direct other funded research programs, and radiologists with related expertise. The goals of the consensus panel were to identify the attributes associated with successful research programs and to develop an action plan for radiology research based on these characteristics.

Academic Medical Centers↗