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The present eye-movement study assessed the effect of expertise on eye-movement behaviour during image perception in the medical domain. To this end, radiologists, computed-tomography radiographers and psychology students were exposed to nine volumes of multi-slice, stack-view, axial computed-tomography images from the upper to the lower part of the abdomen with or without abnormality. The images were presented in succession at low, medium or high speed, while the participants had to detect enlarged lymph nodes or other visually more salient abnormalities. The radiologists outperformed both other groups in the detection of enlarged lymph nodes and their eye-movement behaviour also differed from the other groups. Their general strategy was to use saccades of shorter amplitude than the two other participant groups. In the presence of enlarged lymph nodes, they increased the number of fixations on the relevant areas and reverted to even shorter saccades. In volumes containing enlarged lymph nodes, radiologists’ fixation durations were longer in comparison to their fixation durations in volumes without enlarged lymph nodes. More salient abnormalities were detected equally well by radiologists and radiographers, with both groups outperforming psychology students. However, to accomplish this, radiologists actually needed fewer fixations on the relevant areas than the radiographers. On the basis of these results, we argue that expert behaviour is manifested in distinct eye-movement patterns of proactivity, reactivity and suppression, depending on the nature of the task and the presence of abnormalities at any given moment.

To explore the possibility to use 1.5 T MRI in imaging of accumulating gadolinium (Gd) into inflamed endocrine pancreas (insulitis), we compared intravenously delivered IL-2-Gd-DTPA and Gd-DTPA (Magnevist®) in phenotypically healthy 12 weeks old female non-obese diabetic (NOD) mice. At 1 to 48 h after the injection mice were sacrificed and the pancreas-to-background ratio was determined using MRI. In addition Gd concentration of the pancreas and plasma were measured. The pancreas-to-plasma ratio of Gd was 25-fold 24 h after the i.v. injection of IL-2-Gd-DTPA. At the same time the pancreas-to-background ratio measured with 1.5T MRI was 1.5-times higher in the NOD mice receiving IL-2-Gd-DTPA than Magnevist ® (271 ± 37 vs. 183 ± 0,1, P = 0.04) indicating that sufficient differences may exist between IL-2-Gd-DTPA accumulating in the pancreas and in the surrounding tissues to support the use of MRI for imaging of pancreatic insulitis.

The objective of the study was to test the hypothesis that resorbable radio-opaque bioactive glass markers can be used in radiostereometric analysis (RSA). Cones made from (1) bioactive glass 1-06 with 2.5 wt.% BaSO(4), (2) glass 1-06 with 10 wt.% BaSO(4), (3) glass 1-06 without any additives and (4) nearly inert glass were created. The in vitro surface reactivity, as a surrogate of bioactivity, was analyzed using a simulated body fluid (SBF) immersion test. The in vivo performance was evaluated in the rat femur using biomechanical testing as well as histological and microcomputed tomography analysis of marker incorporation into bone. A phantom model RSA study using a porcine radius with a soft tissue envelope was carried out to determine the accuracy and precision of spherical markers for the measurement of fracture micromotion. SBF immersion studies and bone implantation studies showed that the addition of BaSO(4) slightly reduced surface reactivity in vitro and the bone-bonding properties of the bioactive glass in vivo. In the simulated RSA study with the selected resorbable marker composition (bioactive glass with 10 wt.% BaSO(4)), the accuracy of translation and rotation measurements in the longitudinal axis was +/-51 microm and +/-0.87 degrees , respectively. The precision of translation and rotation measurements in the longitudinal axis were 9 microm and 0.18 degrees , respectively. Bioactive glass markers with BaSO(4) additive appear to have adequate bone-bonding properties for marker stability and sufficient radio-opacity for RSA, but further preclinical comparison studies with tantalum markers are necessary.

Due to the restricted accessibility of pancreatic tissue in living man, direct analysis of the events preceding development of autoimmune changes in the pancreas has been problematic. In vivo imaging of insulitis might markedly increase understanding of the events and timing of the events that are necessary for the progression toward overt type 1 diabetes.To evaluate possibilities to visualize insulitis in man in vivo with positron emission tomography, we studied 12 male patients (age 26 +/- 7 yr) with newly diagnosed type 1 diabetes (duration range 0-7 months) and nine age- and sex-matched healthy controls after an overnight fast using 2-[(18)F]fluoro-2-deoxy-D-glucose and [(11)C]methionine. For definition of the regions of interest, pancreas was localized with magnetic resonance imaging or computed tomography-positron emission tomography.Glucose uptake to the pancreas was markedly higher in the patients with type 1 diabetes than in the healthy controls (22.9 +/- 6.4 vs. 17.8 +/- 6.0 micromol/kg.min, P = 0.039). Glucose uptake to the pancreas of the patients was inversely associated with the duration of diabetes (r = -0.58; P = 0.024), so that in patients with newly diagnosed type 1 diabetes, glucose uptake was higher than in the healthy controls or patients with long duration of diabetes. Methionine uptake to the pancreas of the patients was similar as in the controls (3.7 +/- 1.9 vs. 4.6 +/- 2.4 micromol/kg.min, P = 0.21).In patients with type 1 diabetes, glucose uptake to the pancreas is enhanced at or soon after the time of diagnosis.

The value of compression sonography was assessed to reduce the number of phlebographies otherwise necessary when deep venous thrombosis (DVT) is suspected among hospital patients. Compression sonography was used to study 119 prospective hospital patients who were suspected of having DVT of the lower extremity. The results were compared to those by phlebography. There were 44 DVTs detected by phlebography; ten of these were located only in the calf, below the knee. Of the remaining 34 femoropopliteal DVTs 33 were detected by the compression sonography technique. It is concluded that the use of compression sonography for primary investigation of suspected DVT reduces the number of patients who require phlebography to those whose results by compression sonography are negative. In our study, this would have represented a decrease of 28%, corresponding to a reduction of the total diagnostic costs by 10%.

A new fluoroscopic imaging device consisting of an AT-micro-computer and a digital image memory unit has been used in experimental and clinical ventilation studies during a 2-year period. Digital images with 256 shades of gray were collected during one to 3 ventilation cycles at the rate of 6 to 25 images/s and stored on an optical laser disc. Both subtracted time interval difference (TID-) images and images relative, for example, to the mean image of the cycle (REL-images) were produced. The series of images could also be evaluated dynamically using animation sequences or analyzed using region of interest calculations. The method gave dynamic information with adequate spatial resolution and was easy to use in clinical practice. The radiation dose was kept low due to the high kilovoltage and heavy beam filtration technique. In experimental studies the software enabled flexible measurements of physiological pulmonary parameters.

Neonatal meconium aspiration frequently produces severe respiratory distress, which is associated with patchy pulmonary neutrophil influx and inflammatory injury. To examine the effects of pentoxifylline (PTX), a potent anti-inflammatory agent, on regional pulmonary inflammation and ventilation after meconium aspiration, we studied 17 anesthetized and ventilated neonatal piglets (age

The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion analysis. According to perfusion properties, we first devise a novel mathematical function to form a perfusion model. A simple yet accurate approach is further introduced to extract cardiac systolic and diastolic phases from the heart, so that this cardiac information may be utilized to accelerate the perfusion analysis and improve its sensitivity in detecting pulmonary perfusion abnormalities. This makes perfusion analysis not only fast but also robust in computation; consequently, perfusion analysis becomes computationally feasible without using contrast media. Our clinical case studies with 52 patients show that this technique is effective for pulmonary embolism even without using contrast media, demonstrating consistent correlations with computed tomography (CT) and nuclear medicine (NM) studies. This fluoroscopical examination takes only about 2 seconds for perfusion study with only low radiation dose to patient, involving no preparation, no radioactive isotopes, and no contrast media.

This study addressed the question of whether there are any differences in the size and collapsibility of the upper airway measured by digital fluoroscopy, between snorers and controls whilst they were awake and breathing normally; and whether there are any correlations between these measurements and other clinical data. The dynamic changes of the upper airway size were evaluated using digital fluoroscopy in 33 patients and 16 normal controls. The measurements were compared with findings in an overnight sleep study, including a static-charge-sensitive bed (SCSB) and oximeter recordings. The minimum anteroposterior dimension at the velopharyngeal level was smaller in patients with partial upper airway obstruction than in controls (p

Postnatal response of the gall bladder to feeding was studied in 28 preterm infants (gestational age 24-37 weeks) by ultrasonography immediately before feeding and one hour after feeding. Nineteen of the infants were studied once during the first week of life, and nine infants were studied weekly from a postconceptional age of 27-31 until a postprandial gall bladder contraction was seen. A contraction index was calculated as a percentage decrement of the surface area of the gall bladder from its initial value. All preterm infants of more than 33 weeks' gestation showed a gall bladder response to feeding with a contraction index of at least 50%. Very preterm infants (gestational age 27-32 weeks) showed no postprandial gall bladder contraction or the contraction index was under 50%. In a follow up study of nine very preterm infants, the contraction index exceeded 50% at a postconceptional age of 29 to 32 weeks. One infant with prolonged feeding problems had no postprandial gall bladder response before the postconceptional age of 38 weeks. The contraction index increase was dependent on gestational age at birth and on the bolus volume of feeds.

Objective To study bacteria and viruses in maxillary sinuses of patients with primary hypogammaglobulinemia receiving immunoglobulin therapy. Design Prospective cross-sectional study during 6 months. Setting Tertiary care university hospital. Patients Seventeen patients with primary hypogammaglobulinemia (10 males and 7 females; mean age, 39 years [age range, 11-71 years]). Sixteen patients had common variable immunodeficiency, and 1 patient had X-linked agammaglobulinemia. Main Outcome Measures Magnetic resonance imaging and x-ray imaging of paranasal sinuses when patients did not have signs of acute infection and reevaluation 6 months later. Maxillary sinus aspiration and lavage were performed at a follow-up visit. Sinus fluid analysis for bacteria and viruses was performed by culture and by polymerase chain reaction. A questionnaire on symptoms related to sinusitis was administered during the follow-up period. Results Among 17 patients, 9 (53%) had radiologically defined sinusitis without subjective symptoms at study enrollment. At reevaluation 6 months later, radiological findings remained unchanged in two thirds of the patients. Among 15 patients, bacteria were found in sinus lavage samples from 13 patients, and viruses were found in samples from 7 patients. Eight patients had 2 pathogens or more on bacterial culture. Rhinovirus was identified from sinus lavage samples in 5 patients (33%), enterovirus in 3 patients (20%), and respiratory syncytial virus in 1 patient (7%). Pathogenic bacteria were found in maxillary sinuses of all patients who tested positive for rhinovirus and enterovirus. No fungi were found. During the follow-up period, 6 patients reported mucopurulent drainage. Conclusions Bacteria and viruses were commonly found in maxillary sinuses of patients with primary hypogammaglobulinemia. Yearly evaluation by an ear, nose, and throat surgeon is recommended.

In order to evaluate the functional maturity of biliary tract at birth, repeated ultrasound scannings were carried out in 13 healthy newborn infants. All infants were nursed on breast from the age of 2 hours. The gallbladder was full in all infants immediately after birth (longitudinal ellipsoid surface area 1.02 cm2(0.44) (mean(sd)). No response was found to the first nursing. In 3 infants out of 9 (33%) there was a full respose (100% emptying) during the first day of life, while in 2 (22%) the response was partial (47-88% emptying from the initial volume). In the rest 4 (44%) the gallbladder remained full during the first day of life. One of the infants showed no response during the first 3 days of life. The biliary tract dynamics is highly variable after birth, possibly reflecting functional immaturity.

Flexion and extension radiographs of 75 young males with low back pain disclosed abnormal segmental motion of the lumbar spine in 16 patients with translational movements in 20 intervertebral segments. These 16 patients were further investigated by magnetic resonance imaging to assess disc degeneration in the unstable segments. On T2-weighted images of the 20 segments, the disc was normal in 13 and degenerated in only 7 patients. Thus, the initial factor in lumbar instability in young patients with low back pain is not always degeneration of the disc.