Computed Tomography Research Papers - Academia.edu (original) (raw)

Objective To examine the effects of positive end-expiratory pressure (PEEP) on extravascular lung water (EVLW), lung tissue, and lung volume. Design and setting Experimental animal study at a university research facility. Subjects Fifteen... more

Objective To examine the effects of positive end-expiratory pressure (PEEP) on extravascular lung water (EVLW), lung tissue, and lung volume. Design and setting Experimental animal study at a university research facility. Subjects Fifteen adult sheep. Interventions All animals were studied before and after saline washout-induced lung injury while ventilated with sequentially increasing PEEP (0, 7, 14, or 21 cmH2O). Measurements and results Lung volume was determined by computed tomography and EVLW by the thermal dye dilution technique. Saline washout significantly increased lung tissue volume (21±3 to 37±5 ml/kg) and EVLW (9±2 to 36±9 ml/kg). While increasing levels of PEEP reduced EVLW (30±7, 24±8, and 18±4 ml/kg), lung tissue volume remained constant. Total lung volume significantly increased (50±8 ml/kg at PEEP 0 to 77±12 ml/kg at PEEP 21). Nonaerated lung volume significantly decreased and was closely correlated with the changes in EVLW (r=0.67). In addition, a highly significant correlation was found between PEEP-induced decrease in nonaerated lung volume and decrease in transpulmonary shunt (r=0.83). Conclusions The main findings are as follows: (a) PEEP effectively decreases EVLW. (b) The decrease in EVLW is closely correlated with the PEEP-induced decrease in nonaerated lung volume, making EVLW a valuable bedside parameter indicating alveolar recruitment, similar to measurements of transpulmonary shunt. (c) As excess tissue volume remained constant, however, EVLW may not be suitable to reflect overall severity of lung disease

Aim Automatic CT dataset classification is important to efficiently create reliable database annotations, especially when large collections of scans must be analyzed. Method An automated segmentation and labeling algorithm was developed... more

Aim Automatic CT dataset classification is important to efficiently create reliable database annotations, especially when large collections of scans must be analyzed. Method An automated segmentation and labeling algorithm was developed based on a fast patient segmentation and extraction of statistical density class features from the CT data. The method also delivers classifications of image noise level and patient size. The approach

Subarachnoid hemorrhage (SAH) is a medical emergency which can lead to death or severe disability. Misinterpretation of computed tomography (CT) in patients with SAH is a common problem. How to improve the accuracy of diagnosis is a great... more

Subarachnoid hemorrhage (SAH) is a medical emergency which can lead to death or severe disability. Misinterpretation of computed tomography (CT) in patients with SAH is a common problem. How to improve the accuracy of diagnosis is a great challenge to both the clinical physicians and medical researchers. In this paper we proposed a method for the automatic detection of SAH on clinical non-contrast head CT scans. The novelty includes approximation of the subarachnoid space in head CT using an atlas based registration, and exploration of support vector machine to the detection of SAH. The study included 60 patients with SAH and 69 normal controls from clinical hospitals. Thirty patients with SAH and 30 normal controls were used for training, while the rest were used for testing to achieve a testing sensitivity of 100% and specificity of 89.7%. The proposed algorithm might be a potential tool to screen the existence of SAH.

We propose a new hierarchical approach to resolution scalable lossless and near-lossless (NLS) compression. It combines the adaptability of DPCM schemes with new hierarchical oriented predictors to provide resolution scalability with... more

We propose a new hierarchical approach to resolution scalable lossless and near-lossless (NLS) compression. It combines the adaptability of DPCM schemes with new hierarchical oriented predictors to provide resolution scalability with better compression performances than the usual hierarchical interpolation predictor or the wavelet transform. Because the proposed hierarchical oriented prediction (HOP) is not really efficient on smooth images, we also

To study the impact of fused (18)F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiation therapy (CRT) planning for patients with esophageal carcinoma.... more

To study the impact of fused (18)F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiation therapy (CRT) planning for patients with esophageal carcinoma. Thirty-four patients with esophageal carcinoma were referred for concomitant radiotherapy and chemotherapy with radical intent. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. PET-images were coregistered using five fiducial markers. Target delineation was initially performed on CT images and the corresponding PET data were subsequently used as an overlay to CT data to define the target volume. FDG-PET identified previously undetected distant metastatic disease in 2 patients, making them ineligible for curative CRT. The Gross Tumor Volume (GTV) was decreased by CT and FDG image fusion in 12 patients (35%) and was increased in 7 patients (20.5%). The GTV reduction was >or=25% in 4 patients due ...

Background: A very-low-energy diet (VLED) can result in sub- stantial,rapidweightlossandisincreasinglyprescribedbeforeobe- sitysurgerytominimizeriskanddifficultybyreducingliversizeand... more

Background: A very-low-energy diet (VLED) can result in sub- stantial,rapidweightlossandisincreasinglyprescribedbeforeobe- sitysurgerytominimizeriskanddifficultybyreducingliversizeand abdominaladiposity.Despiteitsgrowingpopularity,aVLEDinthis setting has received little attention. Objective:The aim of this study was to investigate the efficacy and acceptability of a preoperative VLED. Design: In a prospective observational study, 32 subjects (n 19 men and 13 women) with a mean (SD) age of 47.5 8.3 y and a body mass

Biopsy of the musculoskeletal system is useful in the management of bone lesions particularly in oncology but they are often challenging procedures with a significant risk of complications. Computed tomography (CT)-guided needle biopsies... more

Biopsy of the musculoskeletal system is useful in the management of bone lesions particularly in oncology but they are often challenging procedures with a significant risk of complications. Computed tomography (CT)-guided needle biopsies may decrease these risks but doubts still exist about their diagnostic accuracy. This retrospective analysis of the experience of a single institution with percutaneous CT-guided biopsy of musculoskeletal lesions evaluates the results of these biopsies for bone lesions either in the appendicular skeleton or in the spine, and defines indications. We reviewed the results of 2027 core needle biopsies performed over the past 18 years at the authors' institution. The results obtained are subject of this paper. In 1567 cases the correct diagnosis was made with the first CT-guided needle biopsy (77.3% accuracy rate), in 408 cases the sample was not diagnostic and in 52 inadequate. Within 30 days these 408 patients underwent another biopsy, which was diagnostic in 340 cases with a final diagnostic accuracy of 94%. Highest accuracy rates were obtained in primary and secondary malignant lesions. Most false negative results were found in cervical lesions and in benign, pseudotumoral, flogistic, and systemic pathologies. There were 22 complications (18 transient paresis, 3 haematomas, 1 retroperitoneal haematoma) which had no influence on the treatment strategy, nor on patient outcome. This technique is reliable and safe and should be considered nowadays the gold standard for biopsies of the musculoskeletal system.

Neuroimaging plays a major role in the evaluation of patients with neurologic disorders. The utility of various neuroimaging studies is rapidly increasing in both clinical and research settings. Neurologists should learn about the... more

Neuroimaging plays a major role in the evaluation of patients with neurologic disorders. The utility of various neuroimaging studies is rapidly increasing in both clinical and research settings. Neurologists should learn about the technical aspects, indications, and ...

Congenital nasolacrimal duct mucocele (CNDM) is a very rare condition in newborns. Prolapse or expansion of the mucocele into the nose may lead to respiratory distress and difficulty in feeding. The triad of cystic medial canthal mass,... more

Congenital nasolacrimal duct mucocele (CNDM) is a very rare condition in newborns. Prolapse or expansion of the mucocele into the nose may lead to respiratory distress and difficulty in feeding. The triad of cystic medial canthal mass, dilatation of the nasolacrimal duct and a contiguous sub-mucosal nasal mass on computed tomography (CT) is indicative in the diagnosis of CNDM. The case of a five-week-old girl with infected CNDM is described. The authors aim to emphasize the very rare incidence of CNDM in Polish newborns, delayed diagnosis in the case described and the paramount importance of CT of the head for the correct diagnosis and treatment.

We studied the role of duplex Doppler ultrasonography in the diagnosis of renal obstruction caused by ureteral calculi. Using duplex Doppler sonography, we evaluated the intrarenal hemodynamics of 27 patients who presented to the... more

We studied the role of duplex Doppler ultrasonography in the diagnosis of renal obstruction caused by ureteral calculi. Using duplex Doppler sonography, we evaluated the intrarenal hemodynamics of 27 patients who presented to the emergency department with renal colic. We performed Doppler ultrasonography on patients in whom US did not reveal any pathology causing renal colic and calculated and compared mean RI values of normal and obstructed kidneys and ΔRI values of each group. Threshold levels for the diagnosis of urinary tract obstruction (mean RI ≥ 0.70 and ΔRI ≥ 0.08) were used to determine the sensitivity and specificity of Doppler sonography for the diagnosis of urinary tract obstruction. Patients were investigated for revealing calculi diagnosis either by stone excretion history, intravenous pyelography or non contrast enhanced urinary computed tomography. A total of 162 intrarenal arterial Doppler recordings were made on 54 kidneys. Of the 16 patients with urinary obstruction, 11 (68%) had sonographic evidence of pelvicalyceal dilatation. The mean RI of the 16 obstructed and 11 unobstructed kidneys was 0.69 ± 0.04 and 0.61 ± 0.06 (mean ± standard deviation), respectively. The difference between the mean RI values for each group was statistically significant (P P P

A method for automatic segmentation of pulmonary lobes from computed tomography (CT) scans is presented that is robust against incomplete fissures. The method is based on a multiatlas approach in which existing lobar segmentations are... more

A method for automatic segmentation of pulmonary lobes from computed tomography (CT) scans is presented that is robust against incomplete fissures. The method is based on a multiatlas approach in which existing lobar segmentations are deformed to test scans in which the fissures, the lungs, and the bronchial tree have been automatically segmented. The key element of our method is a cost function that exploits information from fissures, lung borders, and bronchial tree in an effective way, such that less reliable information (lungs, airways) is only used when the most reliable information (fissures) is missing. To cope with the anatomical variation in lobe shape, an atlas selection mechanism is introduced. The method is evaluated on two test sets of 120 scans in total. The results show that the lobe segmentation closely follows the fissures when they are present. In a simulated experiment in which parts of complete fissures are removed, the robustness of the method against different ...