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ABSTRACT: The medical reports of 113 patients operated upon for renal tumors were retrospectively reviewed to assess the value of preoperative embolization. Coils or ethanol were used preoperatively in 55 patients while 58 patients underwent nephrectomy without embolization. The tumors were staged according to the TNM and the Robson staging classification. T1 and T2 tumors as well as T3 and T4 tumors were grouped together for statistical evaluation. There was no significant difference in intraoperative blood loss, operation time and survival rate between patients undergoing preoperative embolization and those who had only nephrectomy. Duration of hospital stay was always longer in the preoperatively embolized group. Preoperative embolization of renal tumors neither improved the patients' outcome nor reduced the surgical risk. Robson's classification, stage III/IV, did not show any significant differences for embolized patients or for those nephrectomized without embolization.
Acta Radiologica 01/2010; 28(3):303-6. · 1.37 Impact Factor
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ABSTRACT: Survival of patients with lung carcinoma is very poor, particularly for patients with advanced disease. There are no early clinical symptoms, and screening with chest radiography has not been recommended. Computed tomography (CT) is superior to radiography for detection of pulmonary nodules but usually is associated with relatively high radiation exposure. Recently, accuracy of low dose CT has been shown to be similar to conventional dose CT. The goal of the current study was to assess the findings of low dose CT of the chest in heavy smokers.
More than 700 heavy smokers (> 20 pack years; age: > 40 years) underwent unenhanced low dose CT of the chest. Detected nodules were classified according to their density (soft tissue, calcified, fat) and size (< 6 mm, 6-10 mm, > 10 mm). In nodules larger than 10 mm with no CT features to suggest a benign lesion, histology was obtained.
In approximately 40% of smokers, nodules smaller than or equal to 10 mm were detected. None was resected. In less than 3% of individuals, lesions larger than 10 mm were detected; 8 were bronchogenic carcinoma. All eight carcinomas were resectable. Lesions for which no histology was obtained were followed with low dose CT.
Low dose CT detected 8 bronchogenic carcinomas in more than 700 heavy smokers. All eight were resectable. Pulmonary nodules measuring up to 10 mm were found in 40% of smokers. The significance of these small lesions has remained unclear.
Cancer 12/2000; 89(11 Suppl):2483-4. · 4.77 Impact Factor
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ABSTRACT: Introduction The increasing use of digital modalities in radiology, technical developments and lower costs of computer systems make PACS now feasible. For economical and organizational reasons the implementation of a PAC system demands a filmless radiology department. However, one problem is still the viewing system. Monitors employed in a digital radiology department have a reduced observer performance compared to regular lightboxes.This is caused by low brightness and contrast, different image sizes and flickering of monitors. In this study a new digital projector, orginally build for High Definition Television (HDTV) was tested as an alternative display station. Observer performance was examined using ROC analysis in comparison to digital radiographs (hard copies) on viewing screens. Material and Methods The new LCD-projector (XH-L 100, Sharp, Japan) worked with the HDTV standard (Muse, NHK), and had a high resolution (1920 x 1035 pixel, landscape mode) and
11/1999;
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ABSTRACT: To compare the number of pulmonary nodules detected at helical low- and standard-dose computed tomography (CT) and to investigate the diagnostic value of low-dose CT with a radiation exposure equivalent to that used at chest radiography.
Two radiologists recorded pulmonary nodules at standard-dose (250 or 100 mA, pitch of 1; 200 mA, pitch of 2) or low-dose CT (50 or 25 mA, pitch of 1 or 2) in five postmortem specimens and 75 patients. Nodules were assessed by size (5 mm or smaller, 6-10 mm, or larger than 10 mm) and by diagnostic confidence ("definite nodule," "definite lesion, not classic nodule," or "questionable lesion, possibly representing a vessel") with the Wilcoxon signed rank test. Artifacts depicted at low-dose CT were recorded.
There were no statistically significant differences in the number of nodules detected at standard- or low-dose CT except in nodules 5 mm or smaller that were assessed as definite nodules at standard- or low-dose CT (25 mA, pitch of 2) (472 vs 397, P < .05). Artifacts that possibly interfered with nodule detection were observed exclusively at CT with 25 mA and a pitch of 2.
Pulmonary nodules were detected reliably at CT with 50 mA and pitch of 2 or with 25 mA and a pitch of 1. However, further reduction of the dose to that used at chest radiography was associated with a significant decrease in the number of nodules 5 mm or smaller that were detected, possibly due to artifacts.
Radiology 10/1999; 213(1):289-98. · 5.73 Impact Factor
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ABSTRACT: Arthroscopic procedures have a low complication rate regarding vascular injury. This report describes a pseudoaneurysm of the right popliteal artery with an arteriovenous shunt following arthroscopic resection of remnants of the posterior horn of the medial meniscus, a complication not previously reported.
CardioVascular and Interventional Radiology 04/1999; 12(3):142-4. · 2.09 Impact Factor
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ABSTRACT: To investigate the field strength dependency of relaxivity values with SH U 555 A, concentration-dependent T1 effects, and findings at dynamic T1-weighted magnetic resonance (MR) imaging in patients with focal liver lesions.
Longitudinal relaxivity (r1) with SH U 555 A was measured in human plasma (0.02-300.00 MHz), and transverse relaxivity (r2) was measured at 10, 20, and 40 MHz. Second, a dilution series in human plasma was used at 1-T, T1-weighted, spin-echo or fast low-angle shot (FLASH) imaging. In 22 patients with focal liver lesions, imaging with the latter sequence was performed with a dose of SH U 555 A of 10 mumol Fe/kg.
The r1 of SH U 555 A decreased with increasing field strength, but was higher at high field strengths than r1 values for gadolinium chelates. Enhancement calculations for different iron concentrations in human plasma demonstrated positive enhancement at concentrations less than 700 mumol Fe/L. Enhancement increased with the degree of T1 weighting and was highest for the FLASH sequence with the shortest TE (+81.4% with 300 mumol Fe/L). Enhancement was positive in the liver for at least 30 seconds and in the spleen for at least 480 seconds.
Signal intensity changes at dynamic T1-weighted MR imaging after bolus injection of SH U 555 A can be explained by dynamic changes in iron-plasma concentration.
Radiology 01/1999; 209(3):831-6. · 5.73 Impact Factor
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Pediatric Radiology 05/1998; 28(4):259. · 1.67 Impact Factor
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ABSTRACT: Evaluation of the diagnostic usefulness of the T1-effect of Resovist (SPIO) for dynamic MRI of the liver.
In-vitro measurements of a dilution series with T1-weighted FLASH and SE sequences and investigation of 25 patients with known focal liver lesions with a T2-weighted TSE sequence and a dynamic T1-FLASH sequence.
T1-weighted MRI with Resovist in vitro showed a positive enhancement at low concentrations and a negative enhancement at higher concentrations. In-vivo T1-weighted dynamic MRI liver parenchyma demonstrated a positive enhancement 30 s post contrast, followed by a continuous slope of signal intensity and a negative enhancement (> or = 60 s). Spleen, portal venous vessels and haemangiomas showed an early increase in signal intensity followed by a decreasing positive enhancement, but without negative enhancement. During the perfusion phase metastases showed a small but not significant increase in signal intensity. In 80% a positive ring enhancement could be observed around metastases.
Resovist exhibits a diagnostically useful T1-effect. An evaluation of the perfusion of focal liver lesions during the distribution phase is possible with dynamic T1-weighted MRI. This approach may further improve characterisation of focal liver lesions.
RöFo - Fortschritte auf dem Gebiet der R 03/1998; 168(3):228-36. · 2.76 Impact Factor
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ABSTRACT: To develop a strategy for the complete work-up of vessel lumen and vessel wall for planning and follow-up of radiological interventions of lower extremity arteries.
A total of 36 patients (21 pre-, 8 post- and 7 pre- and postinterventional) were studied. MRA studies were performed using an ECG-triggered phase contrast technique for the demonstration of intraluminal flow and an axial high resolution time-of-flight technique to assess the vascular wall. All MRA studies were analysed by intraindividual DSA comparison for the assessment of flow and wall structures.
Combined MRA techniques provided a good correlation with DSA for the assessment of vascular flow. The kappa test revealed a value of greater than 0.61 for most on the vessel segments proving a good correlation of both methods. Orthogonal high-resolution TOF-MRA provided additional information for the assessment postinterventional wall haematomas and hard plaques.
Combination of PCA to study flow and axial TOF to study wall pathology improves the usefulness of peripheral MRA.
RöFo - Fortschritte auf dem Gebiet der R 03/1998; 168(3):243-9. · 2.76 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the sensitivity of gradient-and-spin-echo (GRASE) sequences to susceptibility effects. GRASE sequences with 21 and 33 echoes per echo train were compared with a T2-weighted FSE sequence with an echo train length of 5 by means of MRI in phantoms, volunteers (n = 10), and patients (n = 19) with old hemorrhagic brain lesions. All experiments were performed on a 1.0-T clinical MR system (Impact Expert, Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations, of brain areas with physiological iron deposition (red nucleus, substantia nigra), and of areas of old brain hemorrhage were calculated for FSE and GRASE pulse sequences. Areas of old brain hemorrhage were also qualitatively analyzed for the degree of visible susceptibility effects by blinded reading. The CNR of iron oxide tubes and iron-containing brain areas decreased with increasing echo trains of GRASE sequences. The CNR of GRASE sequences decreased when compared with CNR of their FSE counterparts (GRASE 21 echo trains 23.8 +/- 0.8, FSE 5 echo trains 26.7 +/- 0.9; p </= 0.01). Qualitative analysis confirmed these measurements. FSE with an ETL of 5 demonstrated significantly stronger susceptibility effects than their GRASE counterpart with an ETL of 21. The results demonstrate that GRASE sequences do not necessarily compensate for the reduced sensitivity of FSE to susceptibility effects. The complex signal behavior of GRASE makes conventional SE, gradient echo, or FSE sequences containing shorter echo trains preferable when patients with intracranial hemorrhage are clinically evaluated.
European Radiology 02/1998; 8(5):834-8. · 3.22 Impact Factor
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ABSTRACT: To investigate whether phase-contrast MRA is a clinically suited approach to examine arteries of the pelvis and lower extremities.
The study was divided into two parts, a volunteer study and patient study. Three MRA techniques-2D TOF with venous saturation, 3D magnitude contrast and 2D phase contrast with ECG triggering-were intraindividually compared in 15 volunteers and evaluated by three blinded readers. Subsequently, a total of 230 vessel segments of 45 MRA studies using ECG-triggered phase contrast were compared with intraarterial DSA. All vessel segments were scored by three blinded readers using a five-point scale with DSA serving as the gold standard.
ECG-triggered phase contrast provided better image quality than the other MRA techniques as assessed by the Friedman test. Clinical studies demonstrated a significant correlation of DSA and MRA as assessed by the Spearman correlation and kappa statistics for individual readers.
MRA of the pelvis and lower extremities may be performed with 2D ECG-triggered phase-contrast MRA within a reasonable time frame (< 30 min). MRA slabs provide orientation similar to that with DSA projections and good to very good correlation of vessel pathology as shown by kappa statistics.
Der Radiologe 07/1997; 37(7):572-8. · 0.61 Impact Factor
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RöFo - Fortschritte auf dem Gebiet der R 05/1997; 166(4):361-3. · 2.76 Impact Factor
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ABSTRACT: 21 years after radiotherapy for breast cancer, a 63-year-old woman developed a malignant mesenchymoma of the chest wall. The total irradiation dose was 132 Gy. The first clinical symptom of this second malignancy was a slight irregular calcification around the implanted silicon protheses observed in a conventional chest X-ray. Radiation-induced sarcoma is a very rare complication of radiotherapy. In cases of chest wall calcification after radiation therapy further investigation should be carried out, because some patients with radiation-induced sarcoma could be saved, if an early diagnosis is reached.
British Journal of Radiology 05/1997; 70(832):424-6. · 1.31 Impact Factor
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ABSTRACT: To determine the value of MR imaging in differentiating the various causes of human renal allograft dysfunction.
A total of 123 human renal allografts (normal n = 20, acute rejection n = 57, acute tubular necrosis n = 14, interstitial fibrosis n = 11, chromic allograft glomerulopathy n = 11, cyclosporine nephrotoxicity n = 3, cortical necrosis n = 7) were investigated by means of MR imaging. Axial T1-weighted spin-echo images and coronal T1-weighted gradient-echo images were obtained before and after Gd-DTPA injection. Diagnostic parameters included corticomedullary contrast and allograft size and shape on the pre-contrast sequences.
None of the diagnostic parameters used could differentiate among the various diagnostic groups. Diagnostic of cortical necrosis could be made only on post-contrast scans. Contrast-enhanced scans were superior to pre-contrast images in detection of focal allograft lesions. Otherwise, contrast-enhanced scans did not provide any more information than pre-contrast studies. Spin-echo and gradient-echo sequences displayed the same diagnostic value.
MR imaging has a limited value in differentiating the various causes of renal allograft dysfunction.
Der Radiologe 04/1997; 37(3):225-32. · 0.61 Impact Factor
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ABSTRACT: The authors used direct magnification radiographs, combines with texture analysis, to investigate the trabecular structure of human vertebral specimens and compared these techniques with measurement of bone mineral density (BMD) by using quantitative computed tomography to predict bone strength.
Direct magnification radiographs and BMD measurements were obtained from 38 motion segments from the thoracolumbar spines of 11 female human cadavers. Maximum compressive strength (MCS) was determined with a materials testing machine. Morphologic parameters, digital skeletons, and fractal dimension were obtained from the radiographs in three different regions of interest.
Correlations between BMD and MCS were statistically significant (r = .81, P < .01). With morphologic parameters, correlation coefficients of up to .64 (P < .01) were obtained. Use of multivariate regression analysis with one morphologic parameter (the width of the black pixels, or thicknessB) in addition to BMD improved correlations versus MCS (P < .01).
In an experimental setting, BMD showed statistically significant correlation with bone strength, whereas the structural parameters demonstrated only modest correlations. BMD together with one of these measures (thicknessB), however, showed the highest correlation.
Academic Radiology 04/1997; 4(3):167-76. · 1.69 Impact Factor
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ABSTRACT: This report deals with radiologic examinations outside official working hours in a German university hospital and the influence of new government regulations. A total of 65,113 radiologic examinations were requested and performed outside official working hours between 1 July 1990 and 30 Juni 1994. The data were analyzed according to the age and sex of this patient population compared with the entire population studied within this 4-year period. Further analysis included the time of the study, the organ systems investigated, and the radiologic technique. About one-third of requests occurred between 16.00 and 20.00 hours on normal working days and, thus, could be taken care of by late shifts. Another third covers the time between 20.00 and 08.00 hours in the morning, which requires inhouse staff (medical and technical). The remainder of the requests occurred during holidays and weekends in the daytime. The most common request in this analysis was for portable chest examination. About 50% of all portable chest examinations were performed outside regular working hours. In all, 17.2% of all requests involved CT and MRT studies. Government regulation did not change the number, technique, and frequency of radiologic examinations outside official working hours.
Der Radiologe 03/1997; 37(2):124-9. · 0.61 Impact Factor
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ABSTRACT: Um den Stellenwert der MRT bei der Klärung der Fehlfunktion von Nierentransplantaten zu untersuchen, wurden 123 menschliche
Nierentransplantate (unauffällig: n = 20, akute Rejektion: n = 57, akute tubuläre Nekrose: n = 14, interstitielle Fibrose:
n = 11, Transplantatglomerulopathie: n = 11, Cyclosporinschaden: n = 3, kortikale Nekrose: n = 7) MR-tomographiert. An einem
1,5-T-Gerät wurden axiale T1-gewichtete Spinecho- und koronare T1-gewichtete Gradientenechoaufnahmen vor und nach Gabe von
Gd-DTPA akquiriert. Als Beurteilungskriterien wurden der kortikomedulläre Kontrast sowie die Größe und Form des Transplantatorganes
in der Nativuntersuchung herangezogen. Keines der Kriterien ermöglichte die Differenzierung der verschiedenen Diagnosegruppen.
Abgesehen von der kortikalen Nekrose, die nur anhand der kontrastmittelunterstützten Sequenzen erkennbar war, lieferte die
Gd-DTPA-Applikationen für die Differenzierung der verschiedenen parenchymalen Komplikationen keine Zusatzinformationen. Beim
Nachweis fokaler Parenchymläsionen war die Kontrastmittelserie der Nativuntersuchungen überlegen. Die Spinecho- und Gradientenechoaufnahmen
führten zu ähnlichen Resultaten. Schlußfolgernd kann davon ausgegangen werden, daß die statische MRT bei der Klärung der Fehlfunktion
einer Transplantatniere eine untergeordnete Rolle spielt.
Purpose: To determine the value of MR imaging in differentiating the various causes of human renal allograft dysfunction.
Methods: A total of 123 human renal allografts (normal n = 20, acute rejection n = 57, acute tubular necrosis n = 14, interstitial fibrosis n = 11, chronic allograft glomerulopathy n = 11, cyclosporine nephrotoxicity n = 3, cortical necrosis n = 7) were investigated by means of MR imaging. Axial T1-weighted spin-echo images and coronal T1-weighted gradient-echo images
were obtained before and after Gd-DTPA injection. Diagnostic parameters included corticomedullary contrast and allograft size
and shape on the pre-contrast sequences.
Results: None of the diagnostic parameters used could differentiate among the various diagnostic groups. Diagnosis of cortical necrosis
could be made only on post-contrast scans. Contrast-enhanced scans were superior to pre-contrast images in detection of focal
allograft lesions. Otherwise, contrast-enhanced scans did not provide any more information than pre-contrast studies. Spin-echo
and gradient-echo sequences displayed the same diagnostic value.
Conclusions: MR imaging has a limited value in differentiating the various causes of renal allograft dysfunction.
Der Radiologe 02/1997; 37(3):225-232. · 0.61 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate different magnetic resonance imaging (MRI) pulse sequences in the detection of artificial cartilage lesions in small joints using an animal model. A total of 32 artificial cartilage lesions were created in the knee joints of 20 rabbits. Twenty lesions were produced 4 weeks and 12 lesions 1 h before the MRI examination, performed in an extremity coil at 1.0 T. All joints were examined with five imaging sequences: (1) a conventional T1-weighted spin-echo (SE)-sequence (repetition time [TR] 600 ms, echo time [TE] 15 ms), (2) a T2-weighted turbo-SE-sequence (TR 2000 ms, TE 85 ms), (3) a two-dimensional (2D) gradient echo (GE)-sequence (TR 440 ms, TE 10 ms, flip angle 60 degrees) and (4,5) two three-dimensional (3D) GE-sequences (TR 40 ms, TE 7 ms, flip angle 40 degrees, with fat suppression (FS) and TR 30 ms, TE 9 ms, flip angle 40 degrees). Two examinations had to be excluded because of insufficient image quality and the remaining examinations were analyzed by two experienced radiologists. The MRI images were correlated with the pathologic findings and anatomical structures were scored according to a 5-level scale. Direct comparison of the pathological and MRI findings showed that 19 of the 30 artificially induced cartilage lesions were detected with the FS 3D GE-sequence, 13 with the 2D GE-sequence, 11 with the 3D GE-sequence, 3 with the T1-weighted SE-sequence, and 2 with the T1-weighted SE-sequence. The highest percentage of artificial cartilage lesions was demonstrated using a fat-suppressed 3D GE-sequence. However, the analysis of cartilage defects in small joints with optimized sequences as well as clinical routine hardware and software had limitations. Therefore a pilot study was performed analyzing newly developed high resolution FS 3D GE images obtained from 5 rabbit knees with 10 cartilage lesions at 1.5 T. Two sequences were used with 1.0 and 0.5 mm slice thickness, a matrix of 256 x 256 and 512 x 256 and a field of view of 12 x 6 and 8 x 6 cm. In this small subset detection rates were substantially higher than in the 30 rabbit knees examined before.
Magnetic Resonance Imaging 02/1997; 15(8):949-56. · 1.99 Impact Factor
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Der Radiologe 02/1997; 37(1):95-7. · 0.61 Impact Factor
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ABSTRACT: In der Zeit vom 01. Juli 1990 bis zum 30. Juni 1994 wurden 65 113 Untersuchungen außerhalb der Regeldienstzeit durchgeführt.
Die vorliegende Analyse schlüsselt die Leistungen auf nach Alter und Geschlecht im Vergleich zum Gesamtkollektiv dieser Vierjahresperiode,
nach dem Zeitpunkt der Untersuchung, nach den untersuchten Organen und nach der eingesetzten Technik. Ca. 1/3 der Leistungen fallen in den Zeitraum zwischen 16.00 und 20.00 Uhr und könnten durch einen versetzten Tagdienst aufgefangen
werden. Ein weiteres Drittel entfällt auf den Zeitraum zwischen 20.00 und 8.00 Uhr am Folgetag. Der Rest entfällt auf Feiertage
und Wochenenden. Die häufigste Anforderung betrifft Thoraxaufnahmen auf den Intensivstationen. Etwa die Hälfte dieser Untersuchungen
werden außerhalb der Dienstzeit angefertigt; 17,2 % der Untersuchungen im Nacht- und Bereitschaftsdienst betreffen Computer-
und Magnetresonanztomographie. Das am 01. 01. 93 in Kraft getretene Gesundheitsstrukturgesetz führte zu keinen nennenswerten
Verschiebungen hinsichtlich Art, Umfang und Häufigkeit der Untersuchungen im Nacht- und Bereitschaftsdienst.
This report deals with radiologic examinations outside official working hours in a German university hospital and the influence
of new government regulations. A total of 65,113 radiologic examinations were requested and performed outside official working
hours between 1 July 1990 and 30 Juni 1994. The data were analyzed according to the age and sex of this patient population
compared with the entire population studied within this 4-year period. Further analysis included the time of the study, the
organ systems investigated, and the radiologic technique.
About one-third of requests occurred between 16.00 and 20.00 hours on normal working days and, thus, could be taken care
of by late shifts.
Another third covers the time between 20.00 and 08.00 hours in the morning, which requires in-house staff (medical and technical).
The remainder of the requests occurred during holidays and weekends in the daytime.
The most common request in this analysis was for portable chest examination. About 50 % of all portable chest examinations
were performed outside regular working hours.
In all, 17.2 % of all requests involved CT and MRT studies. Government regulation did not change the number, technique, and
frequency of radiologic examinations outside official working hours.
Der Radiologe 01/1997; 37(2):124-129. · 0.61 Impact Factor
