Search results for "Mining"
showing 10 items of 1730 documents
Statistical analysis of life history calendar data
2016
The life history calendar is a data-collection tool for obtaining reliable retrospective data about life events. To illustrate the analysis of such data, we compare the model-based probabilistic event history analysis and the model-free data mining method, sequence analysis. In event history analysis, we estimate instead of transition hazards the cumulative prediction probabilities of life events in the entire trajectory. In sequence analysis, we compare several dissimilarity metrics and contrast data-driven and user-defined substitution costs. As an example, we study young adults' transition to adulthood as a sequence of events in three life domains. The events define the multistate event…
Serial Measurement of Static and Dynamic Cerebrovascular Autoregulation After Brain Injury
2011
In patients with neuronal injury, the knowledge of the status of cerebrovascular autoregulation can help to optimize the management of the cerebral perfusion pressure. This study characterizes dynamic and static cerebrovascular autoregulation during the first 7 days after severe traumatic brain injury or intracranial hemorrhage.After approval from the IRB, 16 patients were studied. Cerebral blood flow velocity (CBFV) was measured daily for the assessment of dynamic (10 patients) and static (16 patients) cerebrovascular autoregulation in both the middle cerebral arteries using the transcranial Doppler sonography. Dynamic cerebrovascular autoregulation (dAR) was measured using the cuff-deflat…
Diagnostic performance of qualitative and radiomics approach to parotid gland tumors: which is the added benefit of texture analysis?
2021
Objective: To investigate whether MRI-based texture analysis improves diagnostic performance for the diagnosis of parotid gland tumors compared to conventional radiological approach. Methods: Patients with parotid gland tumors who underwent salivary glands MRI between 2008 and 2019 were retrospectively selected. MRI analysis included a qualitative assessment by two radiologists (one of which subspecialized on head and neck imaging), and texture analysis on various sequences. Diagnostic performances including sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) of qualitative features, radiologists’ diagnosis, and radiomic models were evaluated. Result…
Ischemic-type biliary lesions after liver transplantation: a retrospective analysis of risk factors and outcome.
2013
BACKGROUND Ischemic-type biliary lesions (ITBL) are the most troublesome complications after liver transplantation. Their cause remains unknown and, although some risk factors have been identified, results from different research groups are often conflicting. The goal of this study was to investigate potential risk factors for ITBL. METHODS 565 transplantations performed between September 1997 and August 2010 were identified and divided into two cohorts: 77 in which the patient developed ITBL and 488 in which no ITBL occurred. The following factors were analyzed: donor age, patient Child-Pugh score, cold ischemia time, total ischemia time, type of perfusion solution, shipped versus non-ship…
The Role of Diffusion-Weighted Magnetic Resonance Imaging in Cholesteatoma Diagnosis and Follow-up: Study With the Diffusion PROPELLER Technique
2012
Abstract Introduction and objectives The diagnosis of cholesteatoma is based on clinical evaluation and computed tomography. New non-echo-planar diffusion-weighted magnetic resonance imaging (MRI) techniques, without intravenous contrast, are capable of differentiating cholesteatoma from inflammatory tissue, cholesterol granuloma and granulation tissues. The technique is very helpful in differential diagnosis of cholesteatoma, mainly after canal wall-up tympanoplasty surgery, to avoid routine second-look surgery in these patients. Congenital cholesteatoma and difficult cases can be detected and correctly diagnosed as well. The aim of this study was to evaluate sensitivity, specificity, posi…
Survival and recurrence after liver transplantation versus liver resection for hepatocellular carcinoma: a retrospective analysis.
1998
Objective This study compares the results of liver transplantation (LTx) and liver resection (LR) for hepatocellular carcinoma (HCC) to test the widespread hypothesis that LTx is the preferable approach for small HCCs. Summary Background Data With respect to scarcity of donor organs and poor results, LTxs for large HCCs are obsolete. Small HCC transplantations have been reported to result in an excellent survival rate. However, the data of comparative studies are controversial. Methods Patients who were treated curatively by LTx (n = 50) or LR (n = 52) for HCC were included in this retrospective study. Survival and freedom from recurrence were analyzed. Patients were stratified according to…
The diagnostic performance of renal function-adjusted D-dimer testing in individuals suspected of having venous thromboembolism
2019
Renal impairment, a source of chronic hypercoagulability[1][1] and inflammation,[2][2] is known to reduce the specificity of the D-dimer test in the diagnosis of venous thromboembolism (VTE).[3][3] This leads to many false positives in such patients and consequently to additional costs, as well as
Characterization of BOLD-fMRI signal during a verbal fluency paradigm in patients with intracerebral tumors affecting the frontal lobe.
2002
Previous studies have indicated that the BOLD-fMRI signal can be modified by tumor processes in close vicinity to functional brain areas. This effect has been investigated primarily for the perirolandic area but there is only a limited number of studies concerning frontal cortical regions. Therefore, the aim of the current study was to characterize BOLD-fMRI signal and activation patterns in patients with frontal brain tumors while performing a verbal fluency task. Six patients (ages 31-56 years) suffering from frontal (5 left sided and 1 right sided) intracerebral tumors were examined with fMRI while performing a verbal fluency task in a blocked paradigm design. Eight healthy volunteers se…
Vascular mapping of the face: B-mode and doppler ultrasonography study.
2015
Background To analyze the face vascularization pattern using B-mode and Doppler ultrasonography, and also propose an arterial vessel mapping. Material and Methods The investigation was performed on 20 ultrasonography exams of facial vessels through linear and endocavitary transducers. We analyzed and determined the average values for diameters, peak systolic velocity and resistive index of the following arteries: external carotid, lingual, deep lingual, sublingual, facial, submental, inferior labial, superior labial, angular, maxillary inferior alveolar, mental, buccal, greater palatine, infraorbital, superficial temporal, transverse facial and frontal. Results Data was obtained allowing th…
Perforator-plus flaps: a new concept in traditional flap design.
2007
Conventional fasciocutaneous flaps in reconstructive surgery, especially in the lower extremities, have limited utility. Traditional flaps are essentially random pattern, often require delays, and are limited in mobility and reach. Islanded fasciocutaneous flaps pedicled on perforators can be raised anywhere on the body and have a reliable blood supply and greater freedom of movement. However, venous compromise is a common problem.A new approach to raising conventional fasciocutaneous flaps while including and retaining perforators in their substance was used to offset these disadvantages. This concept offers a dual blood supply to the flap from the dissected perforator plus the flap base. …