[Process management and controlling in diagnostic radiology in the hospital]. / Prozessmanagement und Controlling in der Diagnostischen Radiologie im Krankenhaus.

Systematic process management and efficient quality control is rapidly gaining importance in our healthcare system. What does this mean for diagnostic radiology departments? To improve efficiency, quality and productivity the workflow within the department of diagnostic and interventional radiology at the University Hospital of Essen were restructured over the last two years. Furthermore, a controlling system was established. One of the pursued aims was to create a quality management system as a basis for the subsequent certification according to the ISO EN 9001:2000 norm. Central to the success of the workflow reorganisation was the training of selected members of the department's staff in process and quality management theory. Thereafter, a dedicated working group was created to prepare the reorganisation and the subsequent ISO certification with the support of a consulting partner. To assure a smooth implementation of the restructured workflow and create acceptance for the required ISO-9001 documentation, the entire staff was familiarized with the basic ideas of process- and quality-management in several training sessions. This manuscript summarizes the basic concepts of process and quality management as they were taught to our staff. A direct relationship towards diagnostic radiology is maintained throughout the text.

Prospective randomized study for an injection protocol for intravenous contrast media in abdominal and pelvic helical CT.

OBJECTIVE: To develop an injection protocol for intravenous administration of contrast media in abdominal and pelvic helical CT which provides optimal contrast enhancement of arterial and venous vessels. MATERIAL AND METHODS: For the study on a Somatom Plus 4 unit, a standard helical CT examination procedure of abdomen and pelvis consisted firstly of a native helical examination of the liver, a second one of the liver after intravenous injection of 120 ml nonionic contrast medium with a constant start delay of 50 s, and subsequently a third helical CT of the lower abdomen and pelvis. 125 patients were randomized for examination under different protocols, varying the injection flow from 2.0-4.0 ml/s and the time delay between the second and the third helical examinations from an additional 20-40 s. The efficacy of the contrast injection was checked by region of interest (ROI) measurements of HUs in aorta, inferior vena cava, and in femoral arteries and veins. The results were compared by t-test statistics. RESULTS: A slow flow rate of 2.0 ml/s led to a higher contrast enhancement in the aorta than a flow rate of 3.0 and 4.0 ml/s. The difference between 2.0 ml/s and 4.0 ml/s was statistically significant. In the inferior vena cava, a flow of 3.0 ml/s caused a better contrast than a flow of 2.0 ml/s or 4.0 ml/s, but the measurements did not reach statistical significance. The measurements in the femoral arteries and veins did not show any significant differences. Maximal enhancement in the pelvic vessels was achieved when the third helical examination was started immediately after the second one had ended. Adding any delay (20 s, 40 s) led to a reduced contrast in the pelvic vessels, with a significant reduction in aorta and femoral arteries. CONCLUSION: For routine abdominal and pelvic helical CT, we recommend an injection of 120 ml contrast medium with a flow rate of 3.0 ml/s. Contrast-enhanced examination of the liver should be started after 50 s, and examination of the lower abdomen and pelvis region should be performed without any further delay. This gives an appropriate contrast in the major vessels.

[Osteitis diagnosis in a group of angiology patients: a comparison of X-ray and nuclear medicine studies]. / Osteitisdiagnostik in einem angiologischen Patientengut: Vergleich von röntgen- und nuklearmedizinischen Untersuchungen.

PURPOSE: Of the study was to examine the ranking of radiographs and bone scans in the diagnosis of osteitis. PATIENTS AND METHODS: 115 patients with arterial occlusive disease in stage Fontaine i.v. were referred for examination of the peripheral skeletal parts of the lower extremity. 126 radiographs and bone scans were taken. The time between the two examinations was 10 days maximum to enable direct comparison. Leukocyte scintigraphy was employed as gold standard. RESULTS: The sensitivity of radiographs was 47% with a specificity of 91%. Sensitivity and specificity of bone scans was 78% for both values. The positive predictive values for radiographs and bone scans were 88% and 85%, the negative predictive values were between 80% and 97%. CONCLUSION: In the majority of cases osteitis can be diagnosed with relatively inexpensive methods such as conventional x-rays and bone scans. Only in unclear cases further examinations such as leukocyte scintigraphy or magnetic resonance imaging should supplement the diagnosis.

[Value of lung filter, asymmetric film-screen technique and digital storage screen radiography in diagnosis of coin lesion]. / Zur Wertigkeit von Lungenfilter, asymmetrischer Film-Folien-Technik under digitaler Speicherfolienradiographie in der Rundherddiagnostik.

AIM: To evaluate the image quality of an asymmetric film-screen combination (a-FSC), a conventional screen-film combination (FSC) at speed class 200, a lung filter, and digital luminescence radiograms in detecting pulmonary nodules. METHODS: Detail perception studies were carried out with an anthropomorphic phantom. The image systems were exposed under standardised conditions with 125 kVp. The systems' perception efficiency was evaluated on the basis of 12.240 single observations with ROC analysis. RESULTS: In the overall evaluation the a-FSC and the filter achieved equally high assessments of 0.878 +/- 0.018 and 0.860 +/- 0.21 respectively (p > 0.05). The 200 speed FSC and the storage phosphor screen radiograms did not differ significantly. In the mediastinum all the tested systems were clearly superior to the 200 speed FSC (p < 0.05). In the lung fields on the other hand the 200 speed system was given a higher assessment of 0.866 +/- 0.026. The a-FSC had slight advantages over the lung filter and the digital imagining modes (p > 0.05). CONCLUSIONS: The a-FSC and digital luminescence radiograms provide significantly more diagnostic information in the mediastinum, together with high detail detectability in the lung fields and without requiring additional dosage.

Bilateral inferior vena cava with azygos continuation but without congenital heart disease complicates routine venous cannulation for cardiopulmonary bypass in an adult.

Attempted venous cannulation with a dual-stage cannula for cardiopulmonary bypass in routine coronary revascularization led to the discovery of an abnormal inferior vena cava in a 65-year-old patient. The operative and postoperative course of the patient were not affected by the inferior caval anomaly. The detailed infradiaphragmatic venous anatomy was elucidated later by MRI and showed bilateral inferior caval veins with azygos continuation. Although this malformation of the inferior cava is rare in adults, the occurrence should be known. Quick recognition and handling should be achieved if detected during cannulation for cardiopulmonary bypass.

Detection of radiographic findings in lung fibrosis using storage phosphor plates.

The aim of this work was to examine the influence of the filter kernel size on the detectability of differing radiological findings in interstitial lung disease. In 97 patients with confirmed pulmonary fibrosis chest radiographs were obtained with a filmscreen system of speed class 200 and with correspondingly exposed storage phosphorous plates. The size of the filter kernel used for the image postprocessing varied between sigma 5 and sigma 70. The detectability of interstitial lung changes was evaluated independently by eight readers on the basis of a defined rating system. The results were analysed using multifactorial analysis of variance with Scheffé test at a significance level of p = 0.05. Small kernel sizes (S 5, S 10) combined with high edge enhancement were only of benefit in the imaging of septal lines, but reduced the detectability of nodular and reticular structures. Good detail detectability of both micronodules and septal lines was obtained with a medium kernel size of sigma 40. Storage phosphor radiography utilizing the appropriate choice of postprocessing parameters provides equivalent image quality for evaluating interstitial lung changes compared with a modern filmscreen technique.

ROC-analysis of detection performance by analogue and digital plain film systems in chest radiography.

PURPOSE: To compare the performances of 4 imaging systems in the diagnostic radiology of the chest: an asymmetric screen-film combination (a-SFC); a conventional screen-film combination of speed class 200 (SFC); a screen-film combination of speed class 200 with an aluminium lung filter; and digital luminescence radiographs (DLR). MATERIAL AND METHODS: Object detectability studies were carried out using an anthropomorphic chest phantom. The images were obtained under standard exposure conditions at 125 kVp. The detection performance of the various systems was evaluated by receiver operating characteristic (ROC) analysis on the basis of a total of 12,240 observations. RESULTS: In the overall evaluation the a-SFC and the SFC plus lung filter received equally high ratings of 0.878+/-0.018 and 0.860+/-0.21, respectively (p>0.05). There was no significant difference between the 200-speed SFC and the storage phosphor radiographs. In the mediastinum all the tested systems were clearly superior to the 200-speed SFC (p<0.05) while in the lung fields the 200-speed SFC received a high rating of 0.866+/-0.026. The a-SFC had slight advantages over the SFC plus lung filter and the 2 digital imaging modes (p>0.05). CONCLUSION: The a-SFC and the digital luminescence radiographs provide a significant gain in diagnostic information in the mediastinum without diminishing detail detectability in the lung fields and without additional radiation exposure.

Effects of varying filter kernel sizes on the image quality of interstitial lung diseases.

PURPOSE: The aim of the study was to optimize the postprocessing of digital luminescence radiographs of interstitial infiltrates of the lung. MATERIAL AND METHODS: Ninety-seven patients with established diseases of the lung parenchyma were examined: 514 pathological details were investigated, using a 200-speed screen-film system and a storage phosphor plate. In digital postprocessing, the size of the filter kernel (S) varied between S 5 and S 70. Based upon 32896 individual evaluations, the image quality was evaluated in multifactorial variance analyses. RESULTS: The digital standards were significantly inferior to the tested screen-film system. The large filter kernel S 70 and the small filter kernels S 5 and S 10, as well as an algorithm for edge enhancement, showed selective advantages in the depiction of nodular or small linear structures. For micronodular and linear structures, kernel sizes of S 20 and S 40 produced equally good results (p > 0.05). CONCLUSION: Whenever optimized postprocessing is involved, storage phosphor radiography is equal to a modern screen-film system and can be substituted for the latter without any loss of image quality; this is especially valid for the imaging of interstitial infiltrates of the lung.

[Use of digital luminescence radiography in voiding cystourethrography]. / Einstaz der digitalen Lumineszenzradiographie bei der Miktionszystourethrographie.

PURPOSE: Optimization of image quality by use of digital luminescence radiography (DLR) in voiding cystoureterography (VCU) instead of a conventional screen film system. PATIENTS AND METHODS: 53 patients with a suspected vesicouretral reflux were examined with a VCU in analogous and digital technique. The X-rays were taken in a sitting position while simultaneously measuring the bladder pressure. An intraindividual comparison was omitted for X-ray saving reasons. In the follow-up 3 patients were examined with the other system. Two radiologists and two urologists compared 60 VCU of 53 patients--30 VCU in conventional screen film and 30 in DLR technique presented in standard and edge-enhanced images--with regard to image quality according to 3-step score (A--good image quality, B--sufficient image quality, C--insufficient image quality). RESULTS: The 59 conventional films were scored 72 times with an A, 76 times with a B, and 72 times with a C, whereas the DLR films were scored 116 times with an A, 72 times with a B, and only 8 times with a C. Hereby the edge-enhanced images were the most useful for distinguishing the bladder shadow from the soft tissue of the thigh and for detecting reflux. Furthermore, the exposure dose when applying DLR could be decreased to 75% in grown-ups and to 57% in children without any significant loss of information. CONCLUSION: The DLR is highly superior to the conventional film screen system because of its relatively high tolerance towards wrong exposures, especially with respect of the sitting position during MCU. With the DLR we obtained 96% and with the conventional system only 63% films usable for diagnosis.

[The use of an asymmetric film-screen combination for the imaging of round pulmonary foci]. / Einsatz einer asymmetrischen Film-Folien-Kombination zur Abbildung pulmonaler Rundherde.

PURPOSE: To examine the diagnostic advantages of an asymmetric film-screen system (a-FSS) compared to a conventional 200-speed FSS with and without anatomical lung filter. METHODS: Standard radiographs were obtained from an anthropomorphic chest phantom with simulated pulmonary nodules. The existence or non-existence of nodules was assessed in 7344 individual observations. The results were evaluated using ROC analysis. RESULTS: In an overall evaluation the a-FSS with an ROC area of 0.873 +/- 0.018 was not significantly superior (p > 0.05) to the lung filter but significantly superior (p < 0.05) to the 200-speed FSS. In the mediastinum the a-FSS and the lung filter were significantly superior (p < 0.05) to the 200-speed FSS. In the lung areas the 200-speed FSS and the a-FSS attained equivalent results (p > 0.05), whereas the lung filter was rated significantly lower (p < 0.05). CONCLUSIONS: Asymmetric FSS improves chest diagnostics, because it yields significantly more diagnostic information in the mediastinum using equivalent x-ray exposure without reducing the image quality in the lung areas in respect of simulated pulmonary nodules.

[ROC analysis in post-processing of image data in digital thoracic radiography]. / ROC-Analyse zur Bildnachverarbeitung digitaler Thoraxaufnahmen.

PURPOSE: To examine the extent to which digital luminescence radiography (DLR) can be used for the imaging of pulmonary nodules and interstitial lung disease in chest radiography without any loss of image quality. Additionally: to examine whether post-processing of image data can optimise the recognizability of varied image details. MATERIALS AND METHODS: Detail perceptibility studies were performed on an anthropomorphic thorax phantom with simulated nodules and small linear and reticular details. Under standard conditions, digital luminescence radiographs were obtained in 7 different image modes, and these were compared with a 200-speed screen-film system. The detection of these systems was evaluated in an ROC analysis on the basis of 19,200 individual observations. RESULTS: Edge enhancement or application of high-frequency-enhancing small filter kernels (S 5) slightly improves the detection of linear structures; however, the illustration of nodular details is markedly reduced. Larger filter kernels (S 20, S 40) make a definitive detection possible--not only of circular, but also of linear details. CONCLUSIONS: Storage phosphor radiographs are equal to the tested analog screen-film-system. The optimization of post-processing can be helpful in the prevention of routine multiple documentations.

Radiological aspects of arteriosclerosis: follow-up study of 588 patients in two different groups.

The authors retrospectively compared two groups of patients who had undergone angiography over a twenty-one-year period. The first group consisted of 348 patients who had angiography in the years 1965-1967. The second group was made up of 222 patients who had had angioplasty in the years 1975-1986. Special risk factors such as diabetes and nicotine abuse were singled out together with localization of lesions and gender distribution.