MRA in patients with cerebrovascular disease: Considerations of clinical effectiveness

Objective: To establish in which clinical contexts cerebral MR angiography (MRA) is routinely carried out in a neurological university department and to describe its clinical impact.

Material and Methods: Medical records, reports of findings and documentation of imaging examinations carried out in all 69 patients referred to the Department of Radiology from the Department of Neurology between 1995 and 1998 for cerebral MRA were evaluated. The clinical impact of all imaging findings was assessed on the basis of the medical records.

Results: Circulatory disturbances in the vertebrobasilor arteries (n=4) were the most frequent indication for investigation. MRA followed CT or duplex sonography in 66 of the 69 patients with a mean delay of 8 days. MRA was considered diagnostically inferior to conventional MR in 11 cases, comparable in 30 and superior in 25. Comparing MRA and duplex sonography, the corresponding figures were 12, 29 and 23. In retrospect, 56 MRAs were judged unnecessary.

Conclusion: Controlled clinical studies on optimal use of MRA are needed to avoid wasting resources and to exploit the method's full diagnostic potential in appropriate cases.

Open-source hardware and software and web application for gamma dose rate network operation

The German Federal Office for Radiation Protection operates a network of about 1800 gamma dose rate stations as a part of the national emergency preparedness plan. Each of the six network centres is capable of operating the network alone. Most of the used hardware and software have been developed in-house under open-source license. Short development cycles and close cooperation between developers and users ensure robustness, transparency and fast maintenance procedures, thus avoiding unnecessary complex solutions. This also reduces the overall costs of the network operation. An easy-to-expand web interface has been developed to make the complete system available to other interested network operators in order to increase cooperation between different countries. The interface is also regularly in use for education during scholarships of trainees supported, e.g. by the 'International Atomic Energy Agency' to operate a local area dose rate monitoring test network.

From dose rate to websites: making measurements accessible, understandable and helpful to the lay public

The key role of public information in emergency preparedness has more recently been corroborated by the experience of the Great Eastern Japan Earthquake and Tsunami and the subsequent nuclear accident at the Fukushima NPP. Information should meet quality criteria such as openness, accessibility and authenticity. Existing information portals of radiation monitoring networks were frequently used even in Europe, although there was no imminent radiation risk. BfS responded by increasing the polling frequency, publishing current data not validated, refurbishing the website of the BfS 'odlinfo.bfs.de' and adding explanatory text. Public feedback served as a valuable input for improving the site's design. Additional services were implemented for developers of smart phone apps. Websites similar to 'ODLInfo' are available both on European and international levels. NGOs and grass root projects established platforms for uploading and visualising private dose rate measurements in Japan after 11 March 2011. The BfS site is compared with other platforms. Government information has to compete with non-official sources. Options on information strategies are discussed.

A new approach to estimate nuclide ratios from measurements with activities close to background

Measurements of low-level radioactivity often give results of the order of the detection limit. For many applications, interest is not only in estimating activity concentrations of a single radioactive isotope, but focuses on multi-isotope analyses, which often enable inference on the source of the activity detected (e.g. from activity ratios). Obviously, such conclusions become questionable if the measurement merely gives a detection limit for a specific isotope. This is particularly relevant if the presence of an isotope, which shows a low signal only (e.g. due to a short half-life or a small transition probability), is crucial for gaining the information of interest. This paper discusses a new approach which has the potential to solve these problems. Using Bayesian statistics, a method is presented which allows statistical inference on nuclide ratios taking into account both prior knowledge and all information collected from the measurements. It is shown that our method allows quantitative conclusion to be drawn if counts of single isotopes are low or become even negative after background subtraction. Differences to the traditional statistical approach of specifying decision thresholds or detection limits are highlighted. Application of this new approach is illustrated by a number of examples of environmental low-level radioactivity measurements. The capabilities of our approach for spectrum interpretation and source identification are demonstrated with real spectra from air filters, sewage sludge and soil samples.

[Sporadic adult form of nemaline myopathy--a difficult differential diagnosis]

We report on a 79 years old female patient with slowly progressive painful weakness of the proximal upper and lower limbs. CK was slightly elevated (242 U 7 l). MRI guided biopsy of the proximal lower limbs revealed the rare findings of nemaline myopathy.

Statistical analysis of uncertainties of gamma-peak identification and area calculation in particulate air-filter environment radionuclide measurements using the results of a Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) organized intercomparison, Part I: assessment of reliability and uncertainties of isotope detection and energy precision using artificial spiked test spectra, Part II: assessment of the true type I error rate and the quality of peak area estimators in relation to type II errors using large numbers of natural spectra

In this paper, the uncertainties of gamma-ray small peak analysis have been examined. As the intensity of a gamma-ray peak approaches its detection decision limit, derived parameters such as centroid channel energy, peak area, peak area uncertainty, baseline determination, and peak significance are statistically sensitive. The intercomparison exercise organized by the CTBTO provided an excellent opportunity for this to be studied. Near background levels, the false-positive and false-negative peak identification frequencies in artificial test spectra have been compared to statistically predictable limiting values. In addition, naturally occurring radon progeny were used to compare observed variance against nominal uncertainties. The results infer that the applied fit algorithms do not always represent the best estimator. Understanding the statistically predicted peak-finding limit is important for data evaluation and analysis assessment. Furthermore, these results are useful to optimize analytical procedures to achieve the best results.

Three years of operational experience from Schauinsland CTBT monitoring station

Data from three years of operation of a low-level aerosol sampler and analyzer (RASA) at Schauinsland monitoring station are reported. The system is part of the International Monitoring System (IMS) for verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The fully automatic system is capable to measure aerosol borne gamma emitters with high sensitivity and routinely quantifies 7Be and 212Pb. The system had a high level of data availability of 90% within the reporting period. A daily screening process rendered 66 tentative identifications of verification relevant radionuclides since the system entered IMS operation in February 2004. Two of these were real events and associated to a plausible source. The remaining 64 cases can consistently be explained by detector background and statistical phenomena. Inter-comparison with data from a weekly sampler operated at the same station shows instabilities of the calibration during the test phase and a good agreement since certification of the system.

Digital amorphous silicon flat-panel detector radiography at different exposure doses versus mammography film: possibility of radiation dose reduction in detecting rheumatologic bone defects

BACKGROUND

Radiographic examinations of the skeleton are the most commonly performed radiologic procedures, even outnumbering examinations of the chest. The imaging systems used in skeletal radiography must meet high standards in terms of contrast and spatial resolution to effectively visualize the high contrast between bone and soft tissue as well as fine bone structures.

PURPOSE

To determine the performance of amorphous silicon flat-panel detector radiography compared to mammography film in detecting rheumatologic bone defects at different exposure doses.

MATERIAL AND METHODS

The study enrolled 44 patients with known or presumed skeletal changes of the hand associated with inflammatory rheumatic diseases. Following a clinically indicated radiographic examination of the peripheral extremities using mammography film, a survey radiograph of one hand was taken in the posteroanterior (PA) view by digital radiography, at the same exposure dose and at a dose reduced to one quarter of the mammography film doses. Four independent radiologists scored the resultant images using the Sharp/van der Heijde and Ratingen scoring methods. The study received University of Cologne Ethics Committee and German Federal Radiation Protection Agency approval.

RESULTS

Compared to mammography film, digital flat-panel detector radiography produced a significantly better image quality at identical uptake doses. A greater number of erosions were detected with the digital flat-panel detector than with mammography film at the same and at reduced doses.

CONCLUSION

Although the spatial resolution of the digital flat-panel system used in this study was poorer than mammography film, this was compensated for by its wider dynamic range and improved contrast resolution, even at the reduced dose.

Die sonographisch gezielte Implantation von Portkathetersystemen über die laterale Vena subclavia

PURPOSE

Retrospective analysis of the success and complication rates of chest port implantation via the lateral subclavian vein.

MATERIALS AND METHODS

Between January 2003 and June 2004, the lateral subclavian vein in 271 patients (186 women, 85 men, mean age 53.2 years) was punctured guided by ultrasound. This access was used to insert a port system, and the catheter tip was placed at the cavoatrial junction. The port reservoir was implanted in a subcutaneous infraclavicular pocket and fixed to the fascia of the pectoralis muscle. Indications for port implantation were chemotherapy (n = 239), total parenteral nutrition (n = 2) and intravenous medication (n = 30). The patient follow-up was mainly performed either by the oncology division of the department of gynecology or by the department of internal medicine.

RESULTS

A chest port catheter system was successfully implanted in all patients. The catheter remained in place for a mean duration of 269.4 days (SD 192.3 days). No complications occurred during implantation. In the post-interventional period, 6 catheter dysfunctions were found (thrombotic 0.09 per 1000 catheter days; mechanic 0.05 per 1000 catheter days). While one local infection occurred in the early post-interventional period, 3 local and 15 systemic infections were independent of the port catheter placement (0.39 per 1000 catheter days). The rate of port catheter ex-plantation due to dysfunction or infection was 0.07 per 1000 catheter days.

CONCLUSION

Ultrasound-guided puncture of the lateral subclavian vein is a safe procedure for the insertion of central venous port catheter systems and had a very low complication rate in our study. For further evaluation of our port placement technique, prospective studies compared to placement through the internal jugular vein are necessary.

[Digital X-ray mammography: comparison of the image quality achievable with a wet laser imager, a dry infrared laser imager and a dry laser imager using direct thermography]

PURPOSE

To compare the image quality of digital X-ray mammographies obtained with wet imagers with that of standard dry imaging technology.

MATERIAL AND METHODS

Beginning 03/08/2003, 200 X-ray mammographies with a digital fullfield mammography system (Lorad Selenia, Lorad/Hologic) were prospectively and consecutively documented with a wet laser imager (Scopix LR 5200, Agfa), a dry infrared laser imager (DryView 8610, Kodak) and a dry imager using the principle of direct thermography (Drystar 4500M, Agfa, N = 166). One X-ray exposure was systematically chosen from each examination and was presented in an anonymous and randomized form to three radiologists who evaluated the films using a structured questionnaire.

RESULTS

The visualization of normal anatomic structures was considered being good to excellent for all imagers with the mean assessments 1.0 - 2.4 for the Drystar 4500M, 1.0 - 2.1 for the DryView 8610 and 1.1 - 2.0 for the Scopix LR 5200. The mean assessments were 0.1 - 0.6 points lower in dense than in normal parenchyma, thus, the parenchymal density is the predominant factor for image quality.

CONCLUSION

In view of the comparable image quality obtained with the different imagers used in the study, individual decisions to purchase a specific imager will be based on economics rather than on diagnostic points of view.

Radiosurgery for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia

The authors evaluated the efficacy of radiosurgery (RS) for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia (HHT AVMs). Two patients with seven HHT AVMs were treated by linear accelerator-RS. Complete obliteration was achieved 18 to 24 months post-treatment without side effects. Because HHT AVMs are small and multiple, RS is superior to microsurgery because it is noninvasive and all AVMs can be treated in one session regardless of their location.

MR-Koronarangiographie: Vergleich von SSFP- und gespoilter GRE-Sequenz (Brightblood-Technik) und TSE-Sequenz (Blackblood-Technik) bei gesunden Probanden

PURPOSE

Comparison of a free breathing steady-state free precession (SSFP), a spoiled gradient-echo (GRE) and a turbo spin-echo sequence (TSE) for imaging of the coronary arteries (MRCA) in healthy volunteers.

MATERIALS AND METHODS

Twenty-two healthy volunteers were imaged with a standard clinical scanner (1.5 T, Intera, Philips), with the right coronary system imaged in 11 and the left coronary system in the other 11 volunteers. Images were obtained with a 3D-SSFP (balanced TFE, TR 6.2 ms, TE 3.1 ms, alpha 65 degrees ), a 3D-GRE (TFE, TR 7.2 ms, TE 2.2 ms, alpha 30 degrees ) and a 2D-TSE (Dual-IR, TR 2RR, TE 25 ms) sequence. The in plane resolution was 0.7 x 0.8 mm for both the SSFP and GRE sequence with an effective slice thickness of 1.5 mm. For the TSE sequence, an in-plane resolution of 0.7 x 0.9 mm and a slice thickness of 3.0 mm were used. All investigations were performed using prospective navigator gating and slice-following technique. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for the blood pool to myocardium and blood pool to epicardial fat were calculated. Image quality and measurement artifacts were assessed for all sequences by 5 independent investigators using a 4- and 5-point grading scale.

RESULTS

CNR was significantly higher for the GRE sequence compared with the SSFP sequence and TSE sequence (mean 20.8 +/- 4.8 vs. 14.6 +/- 5.0 and 10.1 +/- 3.7 for blood pool to myocardium; mean 27.5 +/- 6.3 vs. 16.4 +/- 5.4 and 18.1 +/- 5.7 for blood pool to fat). The SNR revealed no significant differences between the SSFP and GRE sequences. The SSFP and the TSE sequences showed significantly more artefacts than the spoiled GRE sequence. Image quality was graded slightly higher for the GRE than for the SSFP sequence for the right coronary system, while there was no substantial difference in the left coronary system (median 2.1 +/- 0.6 and 2.5 +/- 0.6 vs. 2.5 +/- 0.8 and 2.6 +/- 0.7 for the right and left coronary system). In comparison, image quality was lower with the TSE sequence (median 2.9 +/- 0.5 for the right coronary system with p < 0.05 vs. GRE sequence and 3.0 +/- 0.3 for the left coronary system).

CONCLUSION

For the scan parameters chosen in this study, the GRE-sequence represents the most robust technique for imaging of the coronary arteries. Currently, the TSE sequence is no alternative.

Computed-tomography-guided percutaneous core needle biopsies of suspected malignant lymphomas: impact of biopsy, lesion, and patient parameters on diagnostic yield

PURPOSE

To investigate the diagnostic yield of core needle biopsy in patients with malignant lymphoma.

MATERIAL AND METHODS

Computed-tomography-guided core needle biopsies in patients with malignant lymphoma performed in the period 1996 to 2001 were evaluated retrospectively. A biopsy was considered as "fully diagnostic" if a histological diagnosis, including the histologic subtype in the event of malignant lymphoma, was achieved and the clinical course and CT follow-up of at least 6 months confirmed the biopsy results. A biopsy was regarded as "partly diagnostic" if histological work-up defined malignant lymphoma but not the histological subtype, and if histological diagnosis bore therapeutic relevance. Diagnostic yield was correlated with features such as size of specimen, location and depth of the target lesion, and experience of the investigator.

RESULTS

45 biopsies were performed in 40 patients. With respect to definite histopathological diagnosis, 31 biopsies (68.9%) were diagnostic and 14 (31.1%) non-diagnostic. In 4 cases (8.8%), biopsies yielded partly diagnostic results, since therapy could be scheduled after biopsy without final sub-classification. Statistical analysis of biopsy parameters revealed that sample sizes were significantly larger in the diagnostic group.

CONCLUSION

CT-guided biopsy can be considered as an alternative for lymphoma diagnosis and should be the first interventional procedure. The most important parameter for diagnostic success is the size of the specimen.

Reducing the Radiation Dose During Excretory Urography:Flat-Panel Silicon X-Ray Detector Versus Computed Radiography

OBJECTIVE

The purpose of the study was to examine the possibilities for reducing radiation exposure in uroradiology using digital flat-panel silicon X-ray detector radiography. We compared the subjectively determined image quality of abdominal radiographs and urograms obtained on a digital flat-panel detector radiography system with those obtained on a computed radiography system. SUBJECTS AND METHODS. Fifty patients who had a clinical indication for urography underwent unenhanced abdominal imaging that was alternately performed using flat-panel silicon X-ray detector radiography or computed radiography. For patients who required a second radiograph with contrast medium, the examination modality was changed to avoid exposing the patients to excess radiation. The images obtained on flat-panel X-ray detector radiography were obtained at half the radiation dose of the images obtained on computed radiography (800 speed vs 400 speed). The resulting 50 pairs of images were interpreted by four independent observers who rated the detectability of structures of bone and the efferent urinary tract relevant to diagnosis and compared the image quality.

RESULTS

At half the radiation dose, digital flat-panel X-ray detector radiography provided equivalent image quality of the liver and spleen, lumbar vertebrae 2 and 5, pelvis, and psoas margin on abdominal radiographs. The image quality obtained with digital flat-panel X-ray detector radiography of the kidneys, the hollow cavities of the upper efferent urinary tract, and the urinary bladder was judged to be statistically better than those obtained with computed radiography.

CONCLUSION

With half the exposure dose of computed radiography, the flat-panel X-ray detector produced urograms with an image quality equivalent to or better than computed radiography.

Current indication for endovascular treatment of thoracic aneurysms

The morbidity and mortality for open treatment of thoracic aortic aneurysms have declined over the years, but it is still a major clinical problem. The reason for the mortality is in almost 50% of the cases cardiac failure. Endoluminal treatment of abdominal aortic aneurysm is widely distributed and with promising results, although not as free from complications as expected 10 years ago. This technique has also been adopted for the thoracic aortic aneurysm as the trauma is much less than in open surgery. In our own personal series no specific workup for coronary heart disease has been made and the mortality of stentgrafting of the thoracic aorta was 2.4%. A survey of the world literature, including elective and acute dissections and aneurysms revealed 642 patients treated with stentgraft with a mortality of 6.2%, although no cardiologic work up had been performed. These numbers compete well with those of open surgery, but a systematic prospective comparison would be needed in order to state the real mortality in both groups.

[Stent prostheses in abdominal aortic aneurysm--pre-interventional exclusion of aneurysms of the internal iliac artery]

The technical success of endoluminal grafting in AAAs depends on the complete apposition of the fixation points of the stent graft with the proximal and distal aneurysm neck. Approximately 20% of patients presenting with AAAs have concomitant iliac artery aneurysms. To achieve a complete apposition at the distal landing zone without endoleak, intentional occlusion of the internal iliac artery is needed. To evaluate the inherent complications, our results of ELG were compared to those of the bibliography.

Does celiac trunk stenosis correlate with anastomotic leakage of esophagogastrostomy after esophagectomy?

The formation of a gastric tube for esophageal replacement requires partial devascularization of the stomach and induces microcirculatory changes in the anastomotic region of the gastric fundus. The additional influence of celiac trunk stenosis on anastomotic healing has not been investigated. In total, 23 patients with an esophageal carcinoma underwent transthoracic esophagectomy. Reconstruction was performed by a gastric tube (x22) with cervical or thoracic esophagogastrostomy or colon interposition (x1). All patients had a selective mesenterico-celiacography preoperatively via puncture of the right femoral artery. Preoperative cardiovascular and pulmonary risk factors were assessed. Angiographic findings were correlated to postoperative anastomotic leakage of esophagogastrostomy (x22). In seven out of 23 patients (30.4%), a stenosis of the celiac trunk could be demonstrated (x3 stenosis of 50%, x4 stenosis > 80%). Except for one patient with an additional stenosis of the superior mesenteric artery of > 80%, none of the patients with celiac trunk stenosis developed a postoperative anastomotic leakage of the esophagogastrostomy. Coronary artery disease was the only preoperative risk factor to predict a stenosis of the celiac trunk. Isolated stenosis of the celiac trunk does not seem to impair circulation of the gastric tube.

[Quality control of outpatient imaging examinations in North Rhine-Westphalia, Part II]

PURPOSE

In the state of North Rhine-Westphalia (NRW), Germany, a survey was conducted on radiologic examinations ordered by general practitioners (GPs). Part II of this study aims to determine the quality of the process and outcome. The reference standard is the assessment of both radiologists and physicians without board certification in radiology working at a university hospital and in outpatient facilities.

MATERIALS AND METHODS

AllGPs in NRW were asked to cooperate. Participating GPs filled out a questionnaire for each patient. The patients recorded the symptoms prompting the imaging examinations. The radiologists or other physicians performing the examinations were asked to provide the images and written reports and to complete a questionnaire. A file was created for each of the 394 patients with image documentation of at least one examination. Each file, which included medical history, physical findings, imaging documentation and written report, was sequentially forwarded to a board-certified radiologist and to a physician without board certification in radiology working in a university hospital and in an outpatient facility. All physicians were requested to complete a structured questionnaire for each file.

RESULTS

The referral diagnoses were rated as medically plausible in 81%, the indications for imaging found correct in 76%, the examination techniques considered appropriate in 69%, the clinical question answered in 63%, the interpretation judged medically correct in 50% and all incidental findings documented in 49%. In retrospect, 32 % of the examinations were judged superfluous. The sequence of multiple examinations performed on a particular patient was rated as appropriate in 51%. The interpretation revealed specialty-related differences. The plausibility of the referral diagnoses had a significant impact on the appropriateness of subsequent diagnostic investigations. Marked deficits showed sonography, performance by non-radiologists, self-referrals by GPs, gastroenterologic radiology and the ICD-10 coding (suspicion of cardiovascular disease).

CONCLUSION

In the "best-case" scenario, the process quality proved to have moderate deficiencies and the outcome quality severe deficiencies. In consequence, GPs and radiologists should be more communicative by sharing information and exchanging opinions. GP self-referrals should be restricted. Sonography and examinations performed by physicians without board certification in radiology should undergo stricter quality controls. A more intensive interdisciplinary collaboration is needed to determine the optimum implementation of diagnostic imaging of gastroenterologic and cardiovascular diseases.

[Internal carotid artery dissection at the carotid canal after blunt trauma: case report of endovascular repair and literature review]

Symptomatic dissecting aneurysms of the extracranial internal carotid artery after blunt trauma are not frequent. Medical treatment of these lesions can be ineffective and surgical options present high morbidity. We describe a case successfully treated with endovascular therapy, using a self-expanding stent. The advantages of the endovascular treatment are outlined, the literature on carotid artery injuries by blunt trauma and management strategies are reviewed.

[Quality control of outpatient imaging examinations in North Rhine-Westphalia, part I]

PURPOSE

In the state of North-Rhine Westphalia (NRW), Germany, a survey was conducted on radiologic examinations ordered by general practitioners (GPs). Part I of this study aims to collect characteristic epidemiological data and to assess structural quality.

MATERIALS AND METHODS

All GPs in NRW were asked to cooperate. Participating GPs filled out a questionnaire for each patient. The patients recorded the symptoms prompting the imaging examinations. The radiologists or other physicians performing the examinations were asked to provide the images and written reports and to complete a questionnaire. Two university radiologists documented the pertinent test data from the submitted images and written records. Independently of each other, five university radiologists anonymously reviewed the image quality of each examination using structured questionnaires.

RESULTS

A total of 920 patients gave their informed consent and participated. Questionnaires from 787 patients, 852 GPs and 611 radiologists or other interpreting physicians as well as the complete survey data from 530 examinations were available. Of 1503 examinations, conventional radiography made up 52 %, sonography 17 %, computed tomography (CT) 13 % and magnetic resonance imaging (MRI) 5 %. Most indications involved the musculoskeletal (37 %) and respiratory systems (24 %). Physicians without board certification in radiology interpreted 1 % of the CT examinations, 26 % of the radiographic examinations and 71 % of the sonographic examinations. Of the 174 self-referrals, 1 % involved CT, 33 % conventional radiography and 66 % sonography. Written reports were available for 95 % of all 469 examinations performed by radiologists and 74 % of all 127 examinations conducted by non-radiologists. Only 44 % of the 23 sonographic studies were self-referrals by the patient's GP. On average, the radiographic techniques were acceptable in terms of diagnostic information and radiation hygiene. Conventional radiographs were better exposed when obtained by radiologists than by non-radiologists (p = 0.038). The delineation of anatomical structures was rated as good to acceptable for MRI, CT and conventional radiography, while the image quality was rated as diagnostically insufficient for sonography (p < 0.0001). The image quality of radiographic and sonographic examinations performed by radiologists was superior in comparison to examinations performed by physicians without board certification in radiology (p < 0.0001).

CONCLUSION

Examination technique and imaging quality of MRI, CT and conventional radiography performed on outpatients were in an acceptable diagnostic range, whereas the quality of sonography was inadequate.

[Intravascular ultrasound thrombolysis for recanalization of peripheral arteries: evaluation of an in vitro model and results of a pilot-study]

OBJECTIVES

To evaluate the effectiveness of ultrasound thrombolysis in vitro in comparison with thrombectomy, and in vivo as a pilot-study for the treatment of thrombotic occlusions of peripheral arteries.

METHODS

Under standardized conditions, one-day-old and five-day-old thrombi of whole blood, thrombin-induced thrombi and old organized thrombi of human blood were treated with ultrasound thrombolysis and Amplatz thrombectomy device (ATD). Four patients with arterial occlusive disease of Fontaine stage IIb-III underwent intraarterial ultrasound-thrombolysis, applied to long segmental occlusions of the superficial femoral or iliac artery ranging in duration from three days to one year.

RESULTS

The weight of the thrombi after ultrasound thrombolysis was 1.5 g +/- 0.53 (ATD: 0 g) compared to 3.65 g +/- 0.34 without treatment, with more weight reduction in five-day-old thrombi than in one-day-old thrombi. In vivo, partial recanalization was achieved in a three-day-old femoral occlusion. There was no effect in the other three patients. Urokinase thrombolysis with subsequent PTA and stenting resulted in complete recanalization in three patients.

CONCLUSIONS

Ultrasound thrombolysis in vitro was significantly less effective than ATD. The results of ultrasound thrombolysis were influenced by the age of the thrombus and its in vitro formation. Intravascular ultrasound thrombolysis alone was insufficient to treat occluded peripheral arteries in vivo.

[Development of ultrasonography in a radiological university department from 1994 to 2001]

BACKGROUND

In 1994, 5 % of a total of 25 718 examinations and 7 % of all 4630 B-mode sonograms performed in the Radiology Department, University of Cologne was classified as not indicated. In light of these results, the health care policy guidelines for sonographic indications have been amended.

PURPOSE

The aim of this study was to establish the current rate of non-indicated sonographic examinations performed in routine diagnostics by radiology departments at university hospitals, to determine the reasons for such over-diagnosis and identify which regulatory mechanisms can be implemented to prevent his.

METHOD

We counted the number of 1) B-mode and 2) color-flow Doppler ultrasound imaging procedures carried out in patients who had had no change in symptoms within the previous 4 weeks or who were scheduled without reference to an existing sonogram (double examinations). 3) The reasons for over-diagnosis were analyzed. 4) The 1994 survey was repeated in 2000 with an identical protocol and 5) additionally, a modified survey of the diagnostic questions was conducted.

RESULTS

1) Out of 4,119 patients presenting for the first time to receive a B-mode sonogram, 443 prior sonograms (11 %), 305 CT scans (7 %) and 57 MRI scans (1 %) were documented. 2) Double sonograms were carried out in 6 % of the 1,118 patients presenting for the first time for color-flow Doppler ultrasounds and in 16 % of the 651 patients assigned to receive catheter angiographies with arterial color-flow Doppler. 2) 41 out of 55 (75 %) prior sonograms from non-university settings stated by 94 surgery patients were listed in the medical records. 36 out of 43 (84 %) prior sonograms from the university hospital were repeated in the same patients despite the fact that the medical report with the findings was available. None of the 48 sonograms indicated to confirm a plausible finding yielded any information that was additionally relevant to therapy. 4) In the period April - June, 2000, 12 % of all 15,921 tests and interventions, 26 % of 3,569 B-mode sonograms and 58 % of 1,033 abdominal sonograms performed in adults were classified as having not been indicated. 5) Staging and follow-up were stated as the most common reasons that a sonography was carried out in 46 % of the 1,017 adults who were given B-mode sonograms conducted from Jan - Mar, 2000 and comprised 62 % of the 410 sonograms classified as not or probably not medically indicated.

CONCLUSION

The results showed that a multidisciplinary consensus was required to establish the diagnostic value of sonographic procedures. Therefore, this research group drafted a hospital-internal interdisciplinary guideline for "abdominal transcutaneous B-mode sonography in oncological questions".

[Comparison of flat-panel radiography and computed radiography in urography]

PURPOSE

To evaluate the diagnostic value of digital flat-panel radiography in uroradiology the i. v. urograms of patients who had been examined with computed radiography and digital flat-panel radiography were compared regarding image quality.

METHODS

50 patients who underwent clinically indicated i. v. urography were examined with digital flat-panel radiography and computed radiography. In order to avoid unnecessary double exposure to X-rays, patients were examined either by flat-panel or computed radiography before injection of contrast media. Each further clinically indicated exposure after administration of contrast media was done by alternating the other examination technique. The digital images were compared by 4 radiologists regarding image quality for the detection of defined anatomic structures.

RESULTS

Digital flat-panel radiography showed an image quality of the liver, spleen and both kidneys that was similar to computed radiography. The urinary tract, lumbar spine, pelvis and psoas muscle were significantly better visible on flat-panel radiography images.

CONCLUSIONS

Compared to computed radiography there is no loss of image information by using digital flat-panel radiography in uroradiology. On the contrary, some anatomic structures on abdominal survey images show better image quality. In conclusion, digital flat-panel radiography has the potential to replace computed radiography in uroradiologic examinations.

[Endovascular gamma-irradiation for prevention or restenosis after angioplasty of femoropopliteal de-novo-stenoses-long-term results of a feasibility study]

OBJECTIVES

To evaluate the performance and efficacy of endovascular irradiation after percutaneous transluminal angioplasty (PTA) of de-novo femoropopliteal stenoses in a pilot study.

METHODS

6 patients received non-centered endovascular irradiation (12 Gray at surface of the vessel wall) immediately after angioplasty of de-novo femoropopliteal stenosis, 1 patient was given centered endovascular irradiation using 192-iridium (12 Gray at surface of the vessel wall) Centered irradiation was considered for two other patients. Duplex sonographies and interviews were performed the day before and after PTA and after 1, 3, 6, 9, 12, 18, 24 months up to 4 years. Intraarterial angiography was performed in symptomatic patients.

RESULTS

Non-centered endovascular irradiation was possible in all patients without problems or complications. Centered irradiation was not possible in two patients with the cross-over approach. One thromboembolic complication occurred during centered irradiation. Both restenosis and new stenosis at the edge of irradiated distance occurred in 1/7 patients. No other side effects were observed during follow-up.

CONCLUSIONS

In our pilot study endovascular irradiation after angioplasty of de-novo femoropopliteal stenosis was possible with low rates of complications and restenosis and taking vessel anatomy into account.

Detection of porcine bone lesions and fissures: comparing digital selenium, digital luminescence, and analog film-screen radiography

OBJECTIVE

The purpose of our study was to compare the diagnostic performance of a digital selenium detector (Thoravision) with that of analog film-screen systems and digital luminescence radiography in skeletal radiography for the detection of fissures and lesions in porcine bones.

MATERIALS AND METHODS

One hundred bones taken from domestic pigs (50 ribs and 50 femurs) were divided into two equal groups. Fissures and bone lesions were created in 50 bones and 50 served as controls. The bones were examined using film-screen systems, digital luminescence radiography, and digital selenium radiography at various doses. Digital selenium radiography exposure values were adapted to the image geometry differing from the reference methods with a detector focus distance of 2.15 m. Four radiologists independently evaluated image quality and detectability of fissures and lesions on a five-point scale of confidence. Statistical evaluation was based on receiver operating characteristic curve analysis.

RESULTS

Fissures and bone lesions were detected most reliably using the mammography film-screen system, but the difference in the results of the analog and digital reference images did not achieve statistical significance.

CONCLUSION

Compared with analog film-screen systems, the lower spatial resolution of the digital selenium and digital luminescence radiography systems does not affect detectability of fissures and bone lesions in porcine bone. Selenium is effective in skeletal radiography for detecting fissures and bone lesions. With digital selenium and digital luminescence radiography, the surface dose can be cut to half that required for 200-speed film-screen systems without losing any diagnostically relevant information.

Superselective embolization as palliative treatment of recurrent hemorrhage in advanced carcinoma of the head and neck

We report a case of recurrent major hemorrhage in a patient with advanced head and neck squamous cell carcinoma. Before and between the bleeding episodes, the functional level of the patient was remarkably high. Therefore, an attempt at bleeding control with superselective embolization with Ethibloc was made. Because of its specific characteristics, this substance is almost ideal for the purpose of palliative embolization. The material used and the technique of application are described in detail. After the procedure, no hemorrhage occurred for more than 4 months. We recommend superselective embolization, preferably with Ethibloc, for minimally invasive control of recurrent bleeding as palliative treatment in selected patients with advanced head and neck carcinoma, since significant benefit in terms of the quality of life may result.

[Comparison of digital selenium radiography with an analog screen-film system in the diagnostic process of pneumoconiosis according to ILO classification]

Comparison of digital selenium radiography with an analog screen-film system in the diagnostic process of pneumoconiosis according to ILO classification.

PURPOSE

The aim of the study was to determine the diagnostic value of digital selenium radiography in patients with pneumoconiosis. For this purpose chest x-rays by digital selenium radiography and analog screen-film system were compared according to the ILO classification of pneumoconiosis.

METHOD

After approval of the study by the local ethic commission and the Federal German Office for Radiation Protection 50 patients were subjected to x-rays by digital selenium radiography (Thoravision; Philips Medical Systems, Hamburg, Germany) and analog screen-film system of the same day within the scope of an industrial medicine preventive checkup. Four investigators rated the chest x-rays according to the ILO classification of pneumoconiosis.

RESULTS

The findings demonstrated by chest x-rays according to ILO classification were rated similar by digital selenium radiography and analog screen film systems. Image quality of the digital pictures was rated significantly better.

CONCLUSION

The use of digital selenium radiography in evaluating chest x-rays according to the ILO classification does not result in over- or underestimation of pulmonary pathologies. Hence, in the diagnosis of pneumoconiosis, digital selenium radiography can replace the tested analog screen-film system.

Image quality of digital chest X-rays: wet versus dry laser printers

The aim of this study was to compare the image quality of digital chest x-rays (Thoravision) obtained with 2 "wet" laser imagers of different matrix sizes and a "dry" system. Fifty chest x-rays in 2 planes were printed out in normal (100%) and reduced (61%) format using 3 different systems: 2 "wet" laser imagers (Agfa Matrix LR 3300, 4256 x 5174 pixels, 315 dpi; Agfa Scopix LR 5200, 8512 x 10348 pixels, 630 dpi), and one "dry" system (Agfa Drystar 3000,4352 x 5295 pixels, 330 dpi). All tests yielded normal findings. Anonymous images were evaluated by 4 independent reviewers on record forms rating the detectability of predefined anatomic structures. When the image quality of diagnosis-relevant, anatomic structures was evaluated on digital chest x-rays reproduced in normal and reduced format, the wet laser imagers did not show significant advantages over the dry system, Agfa Drystar 3000. The Agfa Drystar 3000 system is a feasible alternative for reproducing digital images, particularly for decentralized archives.

Abdominal lymphoma staging: is MR imaging with T2-weighted turbo-spin-echo sequence a diagnostic alternative to contrast-enhanced spiral CT?

PURPOSE

To evaluate the diagnostic value of MR imaging in abdominal lymphoma staging, in comparison with that of the established spiral CT, within the context of a prospective study.

METHODS

50 patients with non-Hodgkin (n = 27) and Hodgkin lymphoma (n = 23) were examined with a plain T2-weighted TSE sequence (parameters: TE 90 ms, TR >2.500 ms, slice thickness 8 mm, slice interval 0.8 mm, ETL 20, NEX 4), and with spiral CT following oral and intravenous administration of contrast agent.

RESULTS

Both CT and MR imaging agreed in showing abdominal lymphomas in 34/50 cases. The size of the detected lymphomas was between 1.5-9 cm (mean: 4.3 +/-2.2 cm). In the analysis of the individual lymph node sites, CT showed involvement of the paraaortic lymph nodes in 29/50 patients, compared with 28/50 in MRI, and involvement of the portal lymph nodes in 15/50, compared with 12/50. Both techniques showed the iliac lymph nodes in 21/50 patients, the inguinal lymph nodes in 10/50, and the mesenteric lymph nodes in 11/50. Both techniques also showed focal organ lesions in 12/50 cases.

CONCLUSIONS

In the staging of abdominal lymphomas, MR imaging with a T2-weighted TSE sequence can be regarded as equal to spiral CT in the detection of lymph adenopathy and the demonstration of focal organ lesions. In addition to the absence of ionizing radiation, the advantage of MR imaging is that there is no necessity for oral or intravenous administration of contrast agent.

[Magnetic resonance tomography in the diagnosis of intra-articular tibial plateau fractures: value of fracture classification and spectrum of fracture associated soft tissue injuries]

PURPOSE

To compare magnetic resonance imaging (MRI) and X-ray tomography in assessing the type of fracture, degree of comminution and amount of articular surface depression in acute tibial condylar fractures and to describe the associated soft tissue injuries diagnosed with MRI.

METHOD

27 patients with acute tibial plateau fractures were investigated using linear X-ray tomography and MRI employing T1-weighted and proton density turbo spin echo, STIR, and T2-weighted gradient echo images. Fractures were classified according to the AO classification system. The degrees of depression and comminution were measured and soft tissue injuries were recorded.

RESULTS

Fractures were classified as type B1 in 7, as B2 in 6, and as B3 in 6 cases by MRI. More complex C-type fractures were diagnosed in 8 cases. MR and X-ray grading were consistent with the exception of two B3 fractures, which were graded as B1 by X-ray tomography. X-ray tomography under-estimated the degree of comminution 63% of the patients had either meniscal tears or complete ruptures of their cruciate or collateral ligaments. Ten meniscal tears were diagnosed in 9 of 27 patients. Complete tears of the anterior cruciate ligament were seen in 4, and avulsions of the posterior cruciate ligament in 2 patients.

CONCLUSION

MRI allows a detailed assessment of acute tibial plateau fractures and can replace conventional X-ray tomography. The high rate of fracture-associated soft tissue lesions makes MRI an especially valuable tool.