Assessment and optimisation of the image quality of chest-radiography systems.

A complete evaluation strategy had been developed for thoracic X-ray imaging. It has been validated by investigating five chest-radiography systems, two of these systems after optimising image processing. The systems were a screen-film combination, a selenium drum, a conventional and a transparent imaging plate and a Cs/I-based flat panel detector (the two latter ones have been optimised using different post processing). At first all detectors have been characterised using physical parameters like DQE and MTF. After that all systems have been evaluated by human observer studies using anatomy in clinical images (VGA, ICS) and added pathological structures in thoracic phantom images (ROC). The ranking of the image quality of the systems was nearly the same in all studies. There was a similar assessment of main image quality parameters like spatial resolution, dynamic range and MTF. The modification of image post processing changed the visibility of pathological structures more than the visualisation of the anatomical criteria. The assessment of the clinical image quality has to be done for anatomical structures, and the recognition of pathological structures has to be evaluated.

Digital selenium radiography: anti-scatter grid for chest radiography in a clinical study.

The purpose of this study was to evaluate the diagnostic performance of an additional stationary anti-scatter grid in digital selenium radiography (DSR) compared with images acquired with only an air gap. Chest radiographs were obtained with DSR in 100 patients with and without an anti-scatter grid. Four observers scored 12 anatomical landmarks, catheters and wire cerclages for their visualization in both subsets of images. Statistical analysis was performed using a paired t-test. Anatomical landmarks, catheters and wire cerclages were statistically better visualized in regions of high attenuation when the images were performed with an anti-scatter grid. No statistically significant difference was noted for peripheral regions, nor for sex and weight of the patient between the two modalities. Therefore, an anti-scatter grid is not recommended for chest radiography as it increases the radiation exposure of patients without having a significant impact on visualization for all regions of the chest.

Diagnostic potential of virtual bronchoscopy: advantages in comparison with axial CT slices, MPR and mIP?

The aim of this study was to evaluate the diagnostic potential of virtual endoscopy (VE) and to compare it with axial CT slices, multiplanar reconstructions (MPR), minimal intensity projections (mIP), and bronchoscopy in patients diagnosed with bronchogenic carcinoma. Thirty patients underwent a spiral CT. Axial CT images were transferred to an Onyx workstation (Silicon Graphics, Sun Microsystems, Mountain View, Calif.) for performing virtual endoscopy. Accuracy for this procedure was tested by three radiologists on a monitor in comparison with axial CT slices, MPR, mIP, and bronchoscopy concerning the localization and degree of stenoses. Endoluminal tumors were identified by virtual bronchoscopy with no statistically significant difference of localization or grading of stenosis in comparison with bronchoscopy, axial CT slices, MPR and mIP. Axial CT slices, MPR, and mIP showed poorer results with over- or underestimation of stenoses compared with VE and bronchoscopy. Passing of stenoses was only possible with VE in 5 patients. Virtual endoscopy is a non-invasive method for identification of endoluminal tumors and is comparable to real bronchoscopy.

Prefrontal enlargement of CSF spaces in agoraphobia: a qualitative CT-scan study.

1. This CT study was designed to assess brain morphology in 21 patients with agoraphobia and 21 normal control subjects matched for age and sex. 2. Internal and external CSF spaces were evaluated by qualitative assessment on a 3-point scale (normal, questionable, abnormal). 3. Patients showed bilateral enlargement of prefrontal CSF spaces (p < .05). The rating abnormal" was given in the left hemisphere to 6 (28.6%) of the patients, to 4 (19%) of the patients in the right hemisphere, but to none (0%) of the normal controls. 4. These findings suggest that alterations in brain morphology are involved in the etiology of agoraphobia.

Surgical experience with left atrial myxomas.

Between 1974 and 1982, 16 patients (four men, twelve women, mean age 50.5 years) underwent surgery for left atrial myxoma at the Hannover Medical School. Clinical features encompassed cardiac murmurs (100%) and findings compatible with mitral stenosis (87%), chest pain (37%), arrhythmias (37%), syncope (18%) and malaise (37%). Arterial tumor embolism (to the right leg) occurred in one case. The sedimentation rate was consistently elevated. Sinus rhythm was present in 14 and atrial flutter in two patients. In all but one case, the diagnosis was documented through cardiac catheterization. In recent years, however, noninvasive methods such as echocardiography and computer tomography have proved to be accurate and reliable diagnostic methods such that cardiac catheterization would now appear indicated primarily for patients with additional heart disease and for those over the age of 40 years to rule out the presence of asymptomatic coronary artery disease. Surgery was performed with cardiopulmonary bypass and all patients survived the procedure. In 13 cases the tumor was removed through a right atrial approach with septal incision, in two through the left atrium and in one case both approaches were used. Complete removal of the tumor was achieved in all patients. The tumors were found to arise from the atrial septum in 15 and from the inferior wall of the left atrium in one patient. The size of the tumors ranged from 30 mm in diameter up to 100 mm X 60 mm X 40 mm with weights between 4.8 and 125 grams. Although no residual tumors have been seen during an average observation period of 29.2 months (range nine to 56 months), long-term follow-up, readily accomplished with noninvasive methods, is warranted for such patients.

[CT scan of an extensive cardiac lipoma (author's transl)]. / Computertomographische Darsteilung eines ausgedehnten kardialen Lipoms.

Cardiac primary tumors are rare, and their pattern of signs is often hardly characteristic. This makes diagnosis rather difficult. Surgery well in time - which will usually result in complete cure - is always indicated, since even benign neoplasias may lead to considerable complications. Generally, cardiac lipomas remain small, but in some cases the lipomas may be large and even result in death of the patient. Early diagnosis is now possible via angiocardiography, echocardiography and recently also computed tomography. The advantages of CT scanning are, among others, presentation of an image which can be appreciated at a glance with regard to both the intracavitary and the extracavitary parts of the tumour and their relation to the adjacent organs.