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Registration of dynamic CT image sequences is a crucial preprocessing step for clinical evaluation of multiple physiological determinants in the heart such as global and regional myocardial perfusion. In this work, we present a deformable deep learning-based image registration method for quantitative myocardial perfusion CT examinations, which in contrast to previous approaches, takes into account some unique challenges such as low image quality with less accurate anatomical landmarks, dynamic changes of contrast agent concentration in the heart chambers and tissue, and misalignment caused by cardiac stress, respiration, and patient motion. The introduced method uses a recursive cascade network with a ventricle segmentation module, and a novel loss function that accounts for local contrast changes over time. It was trained and validated on a dataset of n = 118 patients with known or suspected coronary artery disease and/or aortic valve insufficiency. Our results demonstrate that the proposed method is capable of registering dynamic cardiac perfusion sequences by reducing local tissue displacements of the left ventricle (LV), whereas contrast changes do not affect the registration and image quality, in particular the absolute CT (HU) values of the entire CT sequence. In addition, the deep learning-based approach presented reveals a short processing time of a few seconds compared to conventional image registration methods, demonstrating its application potential for quantitative CT myocardial perfusion measurements in daily clinical routine.

The aims of this study were to measure the size of Lister’s Tubercle, the extent of the extensor pollicis longus (EPL) groove and the dihedral angle of the distal dorsal radius. Computer tomography scans of 30 forearms were performed by using a 64-slice Siemens SOMATOM Sensation®CT system (Resolution 0.6 mm). DICOM raw data were calculated to 3D by MIMICS®software (Materialise, Leuven, Belgium). The size of Lister’s Tubercle varied from 1.4 to 6.6 mm (average 3.3 mm) in height radial to the tubercle, and from 5.6 to 18.6 mm (average 13.2 mm) in length. The depth of the EPL groove varied from 0.6 to 3.2 mm (average 1.6 mm). The height on the ulnar side, between the depth of the groove and the tip of the tubercle, varied from 2.2 to 5.8 mm (average 3.4 mm). The dihedral angle of the distal dorsal radius varied from 110° to 135° (average 123°). The variations in height of Lister’s Tubercle and in depth of the EPL groove are considerable. This needs to be taken into account when performing volar plating of distal radius fractures otherwise screws may inadvertently penetrate the dorsal cortex of the radius potentially leading to EPL rupture.

The diagnosis and therapy of pericardial diseases are still a physician's challenge. Advanced CT and MR imaging technologies can display the complete morphology of the heart and the pericardium and of the adjacent thoracic structures with a spatial and contrast resolution below 1 mm. All the macromorphologic determinants of pericardial constriction and their functional sequels may be identified by these remarkable technologies. A careful systematic image analysis defines not only a precise diagnosis but also determines the optimal surgical or conservative therapy for the individual patient and minimizes the risk of perisurgical mortality.

In accidents resulting in severe injuries, a clinical forensic examination is generally abandoned in the initial phase due to high-priority clinical needs. However, in many cases, data from clinical computed tomography (CT) examinations are available. The goals of this prospective study were (a) to evaluate clinical CT data as a basis for forensic reconstruction of the sequence of events, (b) to assess if forensic radiological follow-up reading improves the forensic diagnostic benefit compared to the written clinical radiological reports, and (c) to evaluate if full data storage including additional reconstructed 0.6-mm slices enhances forensic analysis. Clinical CT data of 15 living individuals with imaging of at least the head, thorax, and abdomen following polytrauma were examined regarding the forensic evaluation of the sequence of events. Additionally, 0.6-mm slices and 3D images were reconstructed for forensic purposes and used for the evaluation. At the forensic radiological readings, additional traumatic findings were observed in ten of the 15 patients. The main weakness of the clinical reports was that they were not detailed enough, particularly regarding the localization of injuries and description of wound morphology. In seven cases, however, forensic conclusions were possible on the basis of the written clinical reports, whereas in five cases forensic reconstruction required specific follow-up reading. The additional 0.6-mm slices were easily available and with improved 3D image quality and forensic diagnostics. In conclusion, the use of clinical CT data can considerably support forensic expertise regarding reconstruction issues. Forensic follow-up reading as well as the use of additional thin slices for 3D analysis can further improve its benefit for forensic reconstruction purposes.

To determine the value of digital storage-phosphor radiography (SR) on the detection and identification of subtle lung nodules, postero-anterior (PA) and lateral (LAT) film-screen (FR) chest radiographs were compared with isodose SR images of 45 patients with metastatic malignancies. The SR postprocessing was done with a particular mode previously optimized for routine chest radiography. Pulmonary metastases were found in 34 patients and were proved or excluded by CT (n = 28) or longterm follow-up FR (n = 17). Chest images were divided into four regions for evaluation of image quality, number of lung nodules per region and marked pulmonary structures by receiver-operating characteristics (ROC) analysis (45 patients; 125 nodules; 2810 observations; five readers). Of the nodules selected for an ROC study 82 % were 0.5–1.0 cm in diameter. Overall image quality was rated better for FR concerning lung fields (PA) and mediastinum/hilum (LAT). More lung-field nodules were detected on FR than on SR chest images (P < 0.05). Use of FR was superior to SR in the general identification of nodules (PA chest), especially concerning intermediate (P < 0.01) and subtle abnormalities (P < 0.05), whereas there was no significant difference for LAT chest images. Our results show, that currently FR still has advantages over SR in the detection and identification of subtle lung nodules in routine clinical radiography.

Functional evaluation of swallowing disorders requires rapid imaging modalities. Videofluorography and cinematography are the gold standard, but they have their limitations: no transverse plane imaging is achieved and structural resolution for exact topographic analysis is limited. Three cases preselected by videofluorography were studied to evaluate whether electron beam tomography (EBT) permits more detailed dynamic imaging of swallowing disorders focusing on the mesonasopharyngeal segment, the hypopharynx and the upper esophageal sphincter (UES). Immediately after videofluorographic examination of the oropharyngeal deglutition, EBT is performed. The patient is in a supine position and while the patient swallows a 20 ml bolus of water or diluted iodine containing contrast agent, a sequence of 20 images per level is scanned. The levels, which are determined by using the scout view, are oriented parallel to the hard palate either at the level of the hard palate to image the mesonasopharyngeal segment or just above the hyoid bone to focus on the hypopharynx or at the location of the UES. The scan technique is a single-slice cinemode with a slice thickness of 3 mm (exposure time 100 ms, interscan delay 16 ms, 130 kV, 620 mA). The following structural interactions that we have so far been unable to image can be clearly demonstrated with EBT: (1) during normal swallowing, the mesonasopharyngeal segment is completely and symmetrically closed by the soft palate and Passavant's cushion; (2) lateral hypopharyngeal pouches can be located more precisely; and (3) disorders of the UES can be differentiated into functional or morphologically caused disorders (e.g., goiter or cervical osetophytes). Videofluorography and cinematography are still the gold standard in functional evaluation of swallowing disorders. However, EBT permits dynamic imaging of pharyngeal deglutition in a preselected transverse plane and can give useful additional information concerning functional anatomical changes in the pharynx during swallowing. Further clinical evaluation is needed.

Using electron-beam computed tomography (EBCT) with short exposure times of 100 or 50 ms and the capability of acquiring up to 2 x 17 images/s it is possible to study most of the important morphological and functional determinants of the heart. Various examples of studies in acute and chronic cardiac diseases are shown to demonstrate the use of EBCT to determine quantitatively left ventricular volumes (ml), myocardial mass (g), wall thickness changes over the cardiac cycle (mm/s), myocardial perfusion (ml/ 100 g/min) and the extent of coronary calcification (calcium score) and qualitatively the state of the proximal 4-6 cm of the subepicardial coronary arteries. The knowledge of these determinants seems very useful in excluding cardiac dysfunction, in the early recognition of cardiac disease and in the evaluation of the haemodynamic severity of coronary artery stenotic lesions. Further interdisciplinary studies are necessary to assess the clinical validity of these cardiac determinants, especially myocardial perfusion, using this advanced CT technology.

Myocardial perfusion is one of the most important functional parameters of the heart. Presently various indirect methods are used to determine coronary blood flow or myocardial perfusion as inertgas-, thermodilution-, Doppler catheter- and radiopharmacological techniques. Electron-beam-computed-tomographical technology is able to perform CT data acquisition with a very short exposure time of 50 ms. Using this method it is not only possible to determine left ventricular volumes but also to measure myocardial perfusion in ml/100 g/min. The measurement of the left myocardial perfusion is performed using the short axis view. This position is obtained by moving the table 25 degrees to the patient's right and 15 degrees caudally. To determine the position of the left ventricle, a localization scan is obtained in multi-slice-mode using all for target-rings, thus obtaining 8 tomographic levels over 68 mm (each tomographic level having a slice thickness of 7 mm, with an interslice gap of 4 mm between each two adjacent tomographic levels). In this short axis position, using the multi slice flow mode with 3 target-rings and after administration of 50 ml of contrast medium intravenously with a flow of 3 ml/s, 6 tomographic levels are imaged. Each tomographic level is obtained 13 times at 80% of the R-R-interval at each 2 or 3 heart beat (ECG-gated). The left ventricular myocardial contrast enhancement is measured by drawing manually the outline of the left ventricular myocardium using time-density-software of the Imatron workstation. For calculation of the myocardial perfusion the so-called "slope method" is used and the results are expressed as the maximum slope of enhancement of the myocardium divided by the difference of the precontrast and peak CT-value in the left ventricle. The global myocardial perfusion is calculated as a mean of all evaluated tomographic levels. In this study left ventricular volumes as enddiastolic volume endsystolic volume and stroke volume were measured and ejection fraction and cardiac output calculated. The measurements were performed in the log axis view. This view is obtained by moving the table 15 degrees to the patients left in a horizontal position. In this long axis position 6 tomographic levels are imaged using the multi-slice-cine-mode with 3 target-rings after administration of 50 ml of contrast medium intravenously with a flow of 3 ml/s. Each tomographic level is obtained 13 times starting at 0% of the R-R-interval (ECG-triggering). The exposure time is 50 ms with an interscan time delay of 8 ms. In 9 studied patients of whom one had 3 significant coronary artery stenotic lesions (50%), 2 patients had each 2 non significant stenotic lesions (50%) and 6 revealed nearly normal coronary angiograms. The mean global myocardial perfusion was 70 ml/100 g/min (min.32 and max. 116 ml/100 g/min). This mean value of 70 ml/100 g/min is reflecting 5% of the cardiac output supposing that the mean heart weight of these patients was 300 g. In this study the mean of the left ventricular muscle mass determined by the use of EBCT was 130 g. A comparative evaluation of coronary angiographic findings in these patients with the measured myocardial perfusion values revealed, that is not sufficient to look only at the absolute values of the measured myocardial perfusion. Furthermore it seems to be necessary to interpret these perfusion values with respect to the calculated cardiac output. Additional studies of well defined patients groups are necessary to determine normal values of myocardial perfusion at rest in patients with and without coronary artery disease. This seems to be important as comparative analysis of myocardial scintigraphic and EBCT-studies is difficult because of methodical inherent differences. The results of this study suggest that despite the presence of some beam hardening artifacts it is possible to measure myocardial perfusion using EBCT in patients with suspected coronary artery disease in the

Functional evaluation of swallowing disorders requires rapid imaging modalities. Videofluorography and cinematography are the gold standard, but they have their limitations: no transverse plane imaging is achieved and structural resolution for exact topographic analysis is limited. Three cases preselected by videofluorography were studied to evaluate whether electron beam tomography (EBT) permits more detailed dynamic imaging of swallowing disorders focusing on the mesonasopharyngeal segment, the hypopharynx and the upper esophageal sphincter (UES). Immediately after videofluorographic examination of the oropharyngeal deglutition, EBT is performed. The patient is in a supine position and while the patient swallows a 20 ml bolus of water or diluted iodine containing contrast agent, a sequence of 20 images per level is scanned. The levels, which are determined by using the scout view, are oriented parallel to the hard palate either at the level of the hard palate to image the mesonasopharyngeal segment or just above the hyoid bone to focus on the hypopharynx or at the location of the UES. The scan technique is a single-slice cinemode with a slice thickness of 3 mm (exposure time 100 ms, interscan delay 16 ms, 130 kV, 620 mA). The following structural interactions that we have so far been unable to image can be clearly demonstrated with EBT: (1) during normal swallowing, the mesonasopharyngeal segment is completely and symmetrically closed by the soft palate and Passavant's cushion; (2) lateral hypopharyngeal pouches can be located more precisely; and (3) disorders of the UES can be differentiated into functional or morphologically caused disorders (e.g., goiter or cervical osetophytes). Videofluorography and cinematography are still the gold standard in functional evaluation of swallowing disorders. However, EBT permits dynamic imaging of pharyngeal deglutition in a preselected transverse plane and can give useful additional information concerning functional anatomical changes in the pharynx during swallowing. Further clinical evaluation is needed.

Noninvasive in vivo assessment of lung density and structure by quantitative computed tomography (QCT) has a long tradition in the scientific literature. Early efforts were limited, however, as reproducibility was insufficient due to a lack of respiratory control during scanning and appropriate evaluation software was missing (e.g. Goddard et al. 1982; Gilman et al. 1983; Van Dyk and Hill 1983; Mueller et al. 1988; Rienmoller et al. 1988). We have worked on the respective methodology to improve both accuracy and precision and to provide specific evaluation capabilities. Decisive steps were the design of spirometric control and gating for the CT scan process (Kalender et al. 1990a, b; Rienmoller et al, 1990), dedicated evaluation algorithms (Kalender et al. 1991; Rienmoller et al. 1991) and quality control measures as described below. All these steps were incorporated into the PULMO CT option on the SOMATOM PLUS which meanwhile is in broad clinical use. Reference data on lung density and histograms in a healthy population for comparison purposes are still missing, however. It is the purpose of this paper to present first results of a multicenter study established to gather such data. These results still have to be considered preliminary. An extended publication is intended when all participating centers will have acquired the planned numbers of examinations.

The spectrum of diagnostic procedures in cardiology has been decisively extended by magnetic resonance (and also by ultrafast computed tomography) because of its superior visualization of morphological (myocardium, pericardium) and functional (LVMM/EDV) parameters. The continuous development of faster echo sequences makes it possible to perform heart studies over a shorter time and to reduce the frequency of movement and ECG-induced image artefacts. This means that magnetic resonance studies will be simplified, the image quality will be improved, and therefore the numbers of heart studies can be expected to increase. With respect to the range of diagnostic procedures available, magnetic resonance can be seen between echocardiography and heart catheter studies. Coronary angiography cannot be replaced at this time. The true potential of magnetic resonance (and also of ultrafast computed tomography), however, cannot be exploited without evaluation of the prognostic parameters that determine the form and the optimal timing for a conservative and/or surgical treatment of defined cardiac diseases. Therefore, systematic interdisciplinary studies are necessary.

Although echocardiography is mostly applied for the diagnosis of heart tumors there are restrictions concerning the representation of the mediastinal and cardial topography in spite of the usage of transoesophageal echocardiography. Computed tomography (CT) and magnetic resonance imaging (MR) are able to give a full representation of the heart and also the thorax with mediastinum, pleura, and lungs. Not only for the diagnosis of various kinds of heart tumors but also for decisions concerning the therapy, the detection of postoperative complications and development are CT and MR very valuable procedures. The ability to deliver a complete cross-section of all cardial, mediastinal, pulmonal and thoracic structures--in contrast to angiocardiography--and without any anatomic restrictions in contrast to echocardiography--is another advantage of CT and MR. Because of the fullness of information CT and MR supply these procedures are especially used for the detailed planning of operative procedures. They are also a big help in determining whether surgery might have to be excluded because a complete tumor resection is not possible anymore.

The following is based on an experimental animal study of Javanese macaques examined by high resolution CT at the end of 27 months exposure to defined amount of quartz and/or high atmospheric pressure [1].

Video-densitograms of the heart of 46 patients were obtained in three projections; these patients had clinically and angiocardiographically confirmed coronary disease of varying severity, or suffered from cardiomyopathy or were normal. The results were compared with levocardiography. The purpose of the investigation was to determine to what extent abnormalities of movement, seen on levocardiography, can also be demonstrated by video-densitometry. Our results show that video-densitometry, compared with levocardiography, has a sensitivity of 97%, a specificity of 44% and an accuracy of 86%. Video-densitometry provides definite proof of abnormal cardiac movement. The differentiation of hypokinesia from akinesia by the two methods is discussed.

150 patients were examined by the double contrast-technique in drug-induced hypotonia of the stomach. They were examined gastroscopically and at the same time biopsies were taken. Comparison of histological and radiological results was performed. There was found an agreement of 82% in the performance of areae gastricae and the histological diagnosis of chronic gastritis.

Das enddiastolische Volumen des linken Ventrikels (LV) wurde bei 23 Patienten aus dem untergrundkorrigierten enddiastolischen Zählrateninhalt (ROI-Technik) bestimmt. Als Grundlage für die Berechnung in Volumeneinheiten diente die Messung einer definierten Menge von venösem Patientenblut (50 ml) in einer Spritze vor der Gammakamera. Die Zählratenabschwächung im Körper wurde durch Berechnung der Weichteilabsorption (Thoraxwand und Ventrikelwand) sowie der LV-Bluteigenabsorption (Rotationsellipsoid mit einer Ventrikeltiefe von l,5mal der Ventrikelbreite der LV-ROI) korrigiert. Weiterhin wurde der Einfluß verschiedener Modelle (homogener, parabolischer und kein Untergrund) für die LV-Untergrundüberlagerung auf die Volumenberechnung überprüft. Die beste Korrelation (r = 0,92) mit kineventrikulographisch (KVG) gewonnenen Volumina (Einebenen-KVG, Flächen-Längen-Methode) ergab sich für die parabolisch gewichtete Untergrundkorrektur, bei der für jedes Bildelement des Ventrikels ein separater Wert für die Untergrundüberlagerung errechnet wird. Die nach Absorptionskorrektur errechneten Volumina zeigten gute Übereinstimmung mit den aus KVG-Daten abgeleiteten Volumina (VMUGA = 0,997 × VKVG − 12,6 ml).

In the bovine, the uterus shows prominent circular folds during early pregnancy. These folds protrude into the lumen nearly at right angles to the uterine wall and, reaching a height of about 2-3 cm in some cases, often reach the center of the uterine lumen. Thus the uterus becomes apparently divided into a number of pocket-like chambers. Endometrial folds are usually found in the pregnant as well as the contralateral uterine horn. Intra-uterine features can be well demonstrated on exenterated bovine uteri without injuring the organ by means of nuclear magnetic resonance imaging with a high resolution performance. This technique was used to examine the uteri of 4 heifers on day 26, 28, 32 and 55 of pregnancy, respectively. The 3-dimensional imaging of these uteri demonstrated the presence of crescent-shaped folds usually at right angles to the long axis of the uterine horn. These endometrial folds explain why the allantochorionic vesicle cannot be demonstrated in toto by transrectal sonography during early pregnancy, apparently being subdivided by the protrusions from the uterine wall. It has been found that the uterus is characterized by 2-3 echo-weak compartments around day 25 of pregnancy and by about 4-6 by day 30. The number may yet increase with progressing pregnancy. Histological sections out of the wall of the pregnant and the contralateral uterine horn have revealed that the folds are composed mainly of the endometrium (Tunica mucosa) and the circular muscle (Stratum circulare).

The aim of the present study was to compare left ventricular myocardial changes due to infarcts, as seen by computed tomography (CT), with the clinically well recognised methods, such as electrocardiography and angiocardiography. Our first group consisted of 57 patients with a clinical diagnosis of coronary heart disease, the second group comprised 19 patients with various cardiac abnormalities. The two groups were included in 530 CT examinations of the heart. The sensitivity of CT, compared with the other methods, was 77-100%, its specificity 50-100% in the first group, which had an infarct frequency of 71-82%. In this group a positive predictive value was found in 80-100%. The second group of patients had an infarct prevalence of 13-18% and a positive predictive value of 50-100%. Sensitivity in this group rose to 100% and specificity to 86-100%.

30 patients with myocardial infarction older than three weeks were examined by MRI prior and following intravenous injection of 0.1-0.2 mmol/kg Gd-DTPA, 201TL-SPECT and cineventriculography. Gd-DTPA did not cause any significant change (p less than 0.05) of T2-values for infarcted or non-infarcted myocardium. Compared with this, signal intensity for T1-weighted images increased after the application of the contrast agent both for normal (26 +/- 14%) and infarcted myocardium (33 +/- 16%). The intraindividual signal intensity ratio for infarcted and normal myocardium increased from 1.06 +/- 0.07 to 1.12 +/- 0.09 after the injection of Gd-DTPA. The diagnosis of myocardial infarction by visual analysis of signal intensity was not possible in individual cases. Myocardial infarction could only be visualized indirectly by morphological changes such as wall thinning and aneurysm.

Infection, hemorrhage and adult respiratory distress syndrome (ARDS) are pulmonary complications occurring after remission induction therapy for acute leukemia. The aim of this study was to analyze the incidence of these causes by serial roentgenogram, clinical, microbiological and laboratory tests in 21 patients (pts) with relapsed acute leukemia (18 x myeloid, 3 x lymphoblastic), an AML-pt (acute myeloid leukemia) suffering from secondary leukemia, and three pts with primary refractory leukemia following treatment with intermediate (IM) and high-dose cytosine arabinoside (HD-Ara C), in combination with amsacrine (AMSA) (n = 19), etoposide (VP 16) (n = 5) or Mitoxantrone (n = 1). Eleven out of 25 pts developed pulmonary complications, one of them with massive hemoptysis and roentgenographic signs of pulmonary bleecling, one suffering from protracted shock after a tumor lysis syndrome, two pts showing symptoms of a cardiogenic pulmonary edema complicating severeCandida pneumonia in one case and legionnaires’ disease in the other. Seven of the eleven pts had a noncardiogenic pulmonary edema with respiratory failure 1–14 days after cessation of induction or consolidation therapy. In six of the seven, there were no signs of cardiogenic, infectious or metabolic reasons, inclucling fluid overload, for the pulmonary edema, one had as a contributing factor aCandida infection of the lung. Three of the seven patients recovered, four died (two following IM and two after HD-Ara C). Other adverse side effects, clearly attributable to HD-Ara C, included delirious state (n = 3), generalized erythema (n = 3), acute pancreatitis (n = 2), acute abdomen (n = 1) and conjunctivitis in almost all patients. In conclusion, the most frequent (7/25) and serious complication following HD-Ara C treatment in our series was a toxic, non-cardiogenic edema of the lung. In our opinion, the clinical evidence for this type of toxicity might have been misinterpreted in many instances in the past, and it should draw close attention in the future.

Left ventricular (LV) enddiastolic volume (EDV) was calculated in 23 patients from background-corrected enddiastolic count rates (ROI technique). The calculation in volume units (ml) was based on the measurement of a well-defined amount of patients' venous blood (50 ml in a syringe) counted by the gamma camera. Decrease in count rate due to tissue attenuation was corrected for by calculation of soft-tissue absorption in the thoracic and LV wall as well as the blood self-absorption within the LV, applying a rotational ellipsoid with an assumed LV depth of 1.5 times that of the LV width within the LV ROI. Furthermore, the influence of various models of LV background superimposition (homogeneous, parabolic and no background) were tested correlatively for calculations of volume. Best correlation with cineventriculographically measured volumes (r = 0.92) was found with a parabolically weighed background correction, determining an individual value of background superimposition for each LV pixel. This approach was chosen because a homogeneous superimposition is an inadequate model to correct for background due to the geometric extension of the LV. Volumes, parabolically corrected were found to correlate most closely to cineventriculography (CVG) (VMUGA = 0.997 X VCVG - 12.6 ml).

Serum ACE activity measured fluorimetrically was found to be 2.95 +/- (SD) 1.76 mu mol/ml x h in 31 untreated patients with sarcoidosis. It was significantly elevated (p less than 0.001) in comparison to 38 healthy controls 0.97 +/- (SD) 0.30 mu mol/ml x h), 81 subjects with miscellaneous lung diseases, 20 corticosteroid treated patients with sarcoidosis and 15 subjects with resolved sarcoidosis. Resolution of sarcoidosis spontaneously or induced by corticosteroids was accompanied in all 17 cases by a decrease of serum ACE activity, in most cases, to normal values. On the other hand 7 out of 9 untreated patients with a chronic course of sarcoidosis did not show a comparable change of ACE. Our results reveal a close relationship between the activity of the disease and the level of ACE in the serum. The determination of the serum activity of ACE and its variations with time is quite useful in the diagnosis and follow-up of sarcoidosis and contributes to a further restriction of necessary operative procedures in the diagnosis of sarcoidosis.

The term "Digital Radiography" covers all x-ray techniques which produce a projected image with the help of digital imaging techniques, which are very similar to a conventional x-ray film image. The advantage of "Digital Radiography" is the possibility of digital image processing, like the subtraction technique, the selective material filtering technique and the quantitative image plotting technique. With the equipments now in use, the digital projected image is produced by the line or on an even level. One example of the in-line projected image is the so-called "topogram", produced via computed tomography equipment. With the help of an x-ray video chain, it is possible to produce digital images on an even level. This technique is used, for example, for "digital video subtraction angiography" (DVSA). Today, digital radiography is clinically used only in the "DVSA" and the "topogram" systems. A survey of the clinical use and the improved future possibilities of digital radiography is given, and the special features of the method are discussed.

With the introduction of the third generation of CT-Scanners with scanning times of 1 to 6 seconds, CT became a well accepted method in the diagnostics of thoracic and mediastinal diseases. The CT changed and partly replaced some of the well established diagnostic procedures of the mediastinum [8, 10, 17]. To differentiate vascular from nonvascular structures in the mediastinum by CT it is mostly necessary to enhance the blood density by means of an intravenously applied contrast agent. By this means cardiac structures [5] like the interventricular septum, the myocardium, the heart chambers, the coronary arteries, the coronary sinus, the peri-epicardium and the subepicardial space will also become visible.

The aim of the present study was to compare left ventricular myocardial changes due to infarcts, as seen by computed tomography (CT), with the clinically well recognised methods, such as electrocardiography and angiocardiography. Our first group consisted of 57 patients with a clinical diagnosis of coronary heart disease, the second group comprised 19 patients with various cardiac abnormalities. The two groups were included in 530 CT examinations of the heart. The sensitivity of CT, compared with the other methods, was 77-100%, its specificity 50-100% in the first group, which had an infarct frequency of 71-82%. In this group a positive predictive value was found in 80-100%. The second group of patients had an infarct prevalence of 13-18% and a positive predictive value of 50-100%. Sensitivity in this group rose to 100% and specificity to 86-100%.