[Minimally invasive therapy of adrenal gland metastasis].
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Publications and source records attributed to R Felix.
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PURPOSE: Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal tract with an increasing detection rate due to improved differentiating methods in current diagnostic pathology. This study evaluates the radiologic characteristics of these neoplasms to discover specific signs leading to an earlier diagnosis. MATERIALS AND METHODS: As part of a randomized phase III clinical trial of the European Organization for Research and Treatment of Cancer (EORTC), 72 patients with advanced stage GIST were treated with the selective tyrosine-kinase-inhibitor imatinib (Glivec, Novartis, Switzerland). For initial staging, 60 patients underwent MRI and 12 patients underwent CT. RESULTS: GISTs are mesenchymal tumors that grow submucosally and exophytically and become multiple, nodular or ovoid in the advanced stage. The predominant findings are peripheral solid structures with strong contrast enhancement and a central necrosis. Metastases are primarily located in the liver, where they appear as oval or round, sharply delineated solitary lesions with central necrosis. CT demonstrates the primary tumors and local recurrences as nearly isodense with the liver. On MRI, the lesions are hypointense on T 1 -weighted sequences and hyperintense on T 2 -weighted sequences, compared to the liver. CONCLUSION: Immunopathology now enables the exact histologic separation of GISTs from other mesenchymal tumors. The radiological morphology is not sufficiently specific to differentiate GISTs from other mesenchymal tumors. In view of new therapeutic options, cognizance of their typical manifestations is of increasing importance for radiologists.
PURPOSE: The determination of tumor volume in ocular tumors is very important for the planning and success of radiation therapy. This study uses an animal model to evaluate the accuracy of MR-based volumetry of ocular tumors. MATERIALS AND METHODS: In a total of 25 porcine eyes obtained from the slaughterhouse, ocular tumors were produced by injecting a mixture of hand creme and Gd-DTPA under ophthalmoscopic guidance. The injected volume varied between 0.05 ml and 2.7 ml. The eyes were examined with a 1.5 Tesla scanner and a 4 cm circular surface coil especially developed for ocular MRI. After data transfer to a separate workstation, volumetric analysis was carried out by three independent radiologists using semiautomated software. The determined volume was compared with the injected volume. RESULTS: Of the 25 prepared porcine eyes, 23 were suitable for volumetric analysis. The injection of the mixture of hand creme and Gd-DTPA produced two different types of tumors. Ophthalmoscopically, 14 ellipsoid and 9 lobulated to mushroom-shaped tumors were found and confirmed by MRI. Minor deviation was found between injected volume and volume calculated by MRI, with a correlation coefficient of 0.96. CONCLUSION: Using appropriate technique, MRI is capable of determining small tumor volumes with high accuracy in an animal model. Minor differences can be expected when transferring the results to clinical studies.
PURPOSE: To determine the correlation of the extent of lesions of the supraspinatus tendon in MRI's of the shoulder with surgical or arthroscopic findings using the classification of Snyders and Batemann, respectively. MATERIALS AND METHODS: The preoperative MRI's of 80 patients (age: 16 - 76/47.4 +/- 14.0 years) which were performed due to various complaints of the shoulder were analyzed retrospectively by two experienced and blinded radiologists. We evaluated the incidence and the extent of partial or complete ruptures of the supraspinatus tendon. After MRI, an arthroscopic or open surgical intervention was performed (= gold standard). Various MR-scanners were used with a field strength of 1.0 T (17 cases), or 1.5 T (63 cases) and flexible or inflexible arthro coils. Additionally to plain MRI, 38 of 80 patients underwent contrast enhanced MRI. The MR and the surgical or arthroscopic findings were compared and statistically analyzed. RESULTS: Neglecting the localization and the extent of discontinuity of the supraspinatus tendon, the sensitivity of the 80 MRI's was 0.93, the specificity 0.69, and the accuracy 0.85. The sensitivity increased to 0.96 with constant specificity and an accuracy of 0.83 excluding the lesions with an extent below 1 cm. Compared with non-enhanced examinations, the contrast enhanced MRI revealed higher sensitivity (+ 7 %, 0.89 vs. 0.96), higher specificity (+ 11 %, 0.64 vs. 0.75), and higher accuracy (+ 8 %, 0.81 vs. 0.89) in depicting lesions of the supraspinatus tendon at all. On T 1 -weighted images, the detection of lesions at all and the differentiation between partial and complete ruptures were improved significantly by contrast enhancement, especially in lesions with an extent below 1 cm. Diagnostic failures were seen in examinations without intravenous contrast application, artifacts, extent of the lesion below 1 cm, differentiating between degeneration and partial rupture of the tendon, differentiating between severely degenerated tendons with partial rupture and complete rupture, and covered ruptures. CONCLUSIONS: The performance and consecutively the analysis of the widely used MRI of the shoulder is often not sufficiently reliable in its present routine form. To be able to compete with other imaging modalities such as sonography, standardized MR protocol, contrast enhancement as needed, avoiding the described source of failure, and an exact analysis should be applied.
PURPOSE: To assess the new method of 3-dimensional echocardiography in comparison to the "gold standard" MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. MATERIALS AND METHODS: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8 +/- 9.7) with a geometrically abnormal left ventricle were examined using a 1.5T scanner with a fast gradient-echo sequence (TR = 14 ms, TE = 2.6 - 2.9 ms, FOV = 300 - 400 mm, flip angle = 20 degrees, matrix = 128 : 256, slice thickness = 5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec (Munich, Germany) system for 3D reconstruction. RESULTS: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 of 18 patients (61 %) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, the correlation was r = 0.97 for the end-systolic volumes, r = 0.98 for the end-diastolic volumes, r = 0.79 for the end-systolic muscle mass and r = 0.77 for the end-diastolic muscle mass. The agreement between both methods was considered good for the calculated end-diastolic volumes and sufficient for the calculated end-systolic volumes. The muscle mass calculations showed larger differences especially for the end-systolic mass. Mean intraobserver variability was 18.6 % for end-systolic and 8.3 % for end-diastolic volumes. CONCLUSION: In patients with an abnormal left ventricular configuration due to congenital heart disease, the new method of 3D-echocardiography is sufficient for volume calculations in preselected patients. The high intraobserver variability is still a limitation of transthoracic 3D-echocardiography in comparison to MRI.
PURPOSE: Implementation of a self-designed, web-based digital image archive incorporating the existing DICOM infrastructure to assure distribution of digital pictures and reports and to optimize work flow. Assessment after three years. MATERIALS AND METHODS: Open-source software was used to guarantee highest reliability and cost effectiveness. In view of rapidly increasing capacity and decreasing costs of hard discs (HDs), HDs were preferred over slower and expensive magneto-optical disk (MOD) or tape storage systems. The number of installed servers increased from one to 12. By installing HDs with increased capacities, the number of servers should be kept constant. Entry and access of data were analyzed over two 4-month periods (after 1.5 and 2 years of continuous operations). RESULTS: Our digital image archive was found to be very reliable, cost effective and suitable for its designated tasks. As judged from the measured access volume, the average utilization of the system increased by 160 %. In the period from January to April 2002, the users accessed 239.8 gigabyte of the stored 873.7 gigabyte image data (27 %). The volume of the stored data added 20%, mainly due to an increase in cross-section imaging. CONCLUSION: The challenge of developing a digital image archive with limited financial resources resulted in a practicable and expandable solution. The utilization, number of active users and volume of transferred data have increased significantly. Our concept of utilizing HDs for image storage proved to be successful.
PURPOSE: Due to the shortage of cadaver donors, living related liver donation (LRLD) has emerged as an alternative to cadaver donation. The expected graft weight is one of the main determinants for donor selection. This study investigates the accuracy of preoperatively performed CT-volumetry to predict the actual weight of the right liver lobe graft. MATERIALS AND METHODS: In a prospective study the weight of the right hepatic lobe was calculated by volumetric analysis based on CT in 33 patients (21 females, 12 males, mean age 42.1 years, median age 41 years) prior to living related liver donation. Graft weight was calculated as the product of CT-based graft volume and 1.00 g/ml (the approximated density of healthy liver parenchyma). The calculated weight was compared with the intraoperatively measured weight of the harvested right hepatic lobe. The difference was used to determine a correction factor for estimating the actual graft weight. RESULTS: Based on the assumption of a parenchymal density of 1.00 g/ml, the preoperatively estimated graft weight (mean 980 g +/- 168 g) deviated +33 % from the intraoperatively measured right hepatic lobe weight (mean 749 g +/- 170 g). By reducing the preoperatively predicted weight of the right hepatic lobe with a correction factor of 0.75, the actual graft weight can be calculated. CONCLUSION: Preoperative estimation of the weight of the right hepatic lobe based on CT of living related liver donors predicts the weight of the right lobe graft with sufficient accuracy by applying a single correction factor. Intraoperative fluid loss (i.e., blood, bile) from the harvested liver as well as variations in parenchymal density may contribute to the observed preoperative overestimation of the actual graft volume by CT-based volumetry.
PURPOSE: The superparamagnetic iron oxide (SPIO) Resovist is a contrast media with shortening of both T(1) and T(2) relaxation time. This study evaluates the impact of SPIO-enhanced T(1)- and T(2)-weighted images for the differentiation of liver lesions. MATERIALS AND METHODS: SPIO-enhanced MRI examinations (1.5 T, Symphony Quantum) of 61 patients were analyzed. Thirty-seven patients had malignant liver lesions (metastases n = 32, HCC n = 5) proven by biopsy or laparotomy, 11 patients had benign liver lesions (FNH n = 2, hemangiomas n = 4, benign cysts n = 5, normal liver on laparoscopy n = 13). After unenhanced T(1)- and T (2)-weighted imaging, a bolus injection of 1.4 ml SPIO (Resovist) was given, followed by T(1)-weighted imaging at 20 s, 60 s, and 5 min and T(2)-weighted imaging at 10 min post injection. A score from 1 (benign) to 5 (malignant) was used by three blinded radiologist for the ROC analysis of the unenhanced T(1)-/T(2)-weighted images (set 1) and of the combinations of unenhanced T(1)/T(2)-weighted and SPIO T(1)-weighted images (set 2), unenhanced T(1)/T(2) and SPIO T(2)-w images (set 3) and all images (set 4). RESULTS: The accuracy of plain MRI (set 1: 56 %) was increased by SPIO-enhanced T(1)-weighted images (set 2: 81 %) and SPIO-enhanced T(2)-weighted images (set 3: 90 %). Best results were obtained using unenhanced T(1)-weighted, unenhanced T(2)-weighted and both SPIO T(1)-weighted and T(2)-weighted images (set 4: 93%). The accuracy of predicting histopathologic diagnosis was 91%. CONCLUSION: For the differentiation of liver lesions, SPIO-enhanced T(2)-weighted images had a greater impact on the accuracy of MRI than T (1)-weighted images, but SPIO-enhanced T(1)-weighted images provided additional information in some patients and should not be deleted.
PURPOSE: Comparison of the performance of virtual and conventional colonoscopy for the detection of colorectal polyps and inflammatory colon diseases using a 16-slice spiral CT scanner. Furthermore, presentation of the first experiences with a new three-dimensional reconstruction mode ("colon-dissection") that dissects the colonic wall like a pathologic-anatomic preparation to increase the sensitivity. MATERIALS AND METHODS: Forty patients were studied using a 16-slice spiral CT (Lightspeed 16, General Electric Medical Systems, Milwaukee, Wisconsin 53201, USA). The examination was performed after standard oral preparation for colonoscopy. The colonic distension was achieved with room air and intravenous butylscopolamine. Images were obtained in supine and prone position using a detector configuration of 16 x 0.625 mm, pitch 1.7, rotation time 0.5 s, 160 mAs and 120 kV. Axial reconstruction with a slice thickness of 0.625 mm. The CT data were assessed by two radiologists on an Advantage Workstation (Volume Analysis 2, USA) using a software with the capabilities of axial, multiplanar and volume rendering, virtual endoscopy, and colon dissection. Conventional colonoscopy was used to determine the sensitivity. RESULTS: A total of 30 polyps were found in 8 patients and a carcinoma was detected in two patients. Colonography identified 4 polyps with a diameter of 10 mm or more, 6 polyps with a diameter of 5 mm to 9.9 mm, 11 polyps with a diameter of 3 to 4.9 mm and 9 polyps with a diameter of 3.0 mm or less. There were two false negative findings (one polyp of 3 mm and one of 4 mm had been overseen) and two false positive findings for polyps (polyps of 4 mm and 6 mm). The sensitivity and specificity for the detection of colonic polyps were 93% and 94% with the "colonic-dissection" mode, 87 % and 94 % with the "virtual-endoscopy" mode and 63 % and 97 % with multi-planar reconstruction, respectively. Depending on the diameter of the colonic polyps, the "colon-dissection" mode ("virtual-coloscopy") had a sensitivity and specificity of 100 % and 100 % for polyps with a diameter over 5.0 mm, 91 % and 82 % for polyps with a diameter from 3.0 to 4.9 mm and 89 % and 78 % for polyps with a diameter under 3.0 mm, respectively. Inflammatory colon diseases presented as thickening of the colon wall over 5 mm. CONCLUSIONS: Virtual colonoscopy with 16-slice spiral CT allows accurate detection of colonic polyps, including small polyps below a diameter of 3 mm. In comparison with the 2D- and 3D-"virtual-endoscopic" reconstruction, the 3D-reconstruction software "colon-dissection" achieves the highest sensitivity for the detection of colonic masses. Therefore, the combination of a 16-slice spiral CT and the "colon-dissection" reconstruction software provides a high resolution in the z-axis for detecting colonic masses and polyps down to a diameter of less than 2 mm, with a sensitivity of about 90 %. This sensitivity is much higher than the sensitivity achievable with 4-slice spiral CT and without "colon-dissection" mode. A thickened colon wall over 5 mm indicates inflammatory colon disease.
OBJECTIVE: Assessment of the value of ultrasound examination in the determination of extracapsular neoplastic infiltration and soft tissue infiltration of cervical lymph nodes. MATERIAL AND METHODS: In a prospective study the results of ultrasound studies in 110 patients with squamous cell carcinoma in the head-neck region were compared with the findings of the histologic examination after neck dissection. RESULTS: Ultrasound examination showed a specificity of 81.8 % in the determination of extracapsular neoplastic infiltration. The sensitivity was only 78.6 % - this was mainly caused by microscopic extracapsular growth, which gave false-negative results. Infiltration of blood vessels were identified in all patients. There was only one false negative diagnosis of muscle infiltration. CONCLUSION: The specificity (81.8 %) and sensitivity (78.6 %) of ultrasound examinations in the diagnosis of extracapsular infiltration in patients with lymph nodes metastasis is promising. But the examiner has to keep in mind that especially microscopic extracapsular neoplastic infiltration cannot be seen in ultrasound.
PURPOSE: Evaluation of the diagnostic value of three-dimensional CT-reconstruction in the pre-operative evaluation of traumatic fractures of the spine, compared with axial slices and two-dimensional reconstruction. MATERIALS AND METHODS: The CT image data of 65 patients with 85 different acute traumatic spine fractures (C 2 through L 5) were collected in a period of 42 months. Retrospectively performed 2D- and 3D-reconstructions were analyzed independently by three CT-experienced readers using the Magerl classification and the readings compared with intraoperative findings or the final diagnoses. RESULTS: The fractures were classified according to the AO-classification as 56 compression, 16 distraction and 13 rotation fractures. Axial slices alone incorrectly classified 2 (1.2 %) of 168 (56 fractures x 3 readers) type A fractures. The CT classification was incorrect in 17 (35.4 %) of 48 (16 fractures x 3 readers) type B fractures and in 31 (79.5 %) of 39 (13 fractures x 3 readers) type C fractures. The 2D-reconstruction increased the percentage of incorrect diagnoses to 13 (7.7 %) type A, to 26 (54.2 %) type B and to 27 (69.2 %) type C fractures. The 3D-mode incorrectly classified 2 of 168 type A fractures (1.2 %), 6 of 48 type B fractures (12.5 %), and 1 of 39 type C fractures (2.6 %). The axial mode was superior to the 2D-reconstructions in type A and type B fractures, but inferior in type C fractures. The percentage of correctly classified type B fractures was significantly higher (p < 0.05) with 3D-reconstruction than with the 2D-mode. In type C fractures, this percentage was significantly higher (p < 0.001) with the 3D-mode than with axial slices or 2D-reconstruction. The interactive monitor analysis of the 3D-reconstructions with additional virtual cutting by the reader improved the analysis, especially the evaluation of the spinal canal. CONCLUSION: The 3D-reconstruction in traumatic spine fractures significantly improves the diagnostic outcome, especially the visualization and classification of rotation fractures. Its disadvantages are a slight increase in artifacts and impaired visualization of small details. Interactive monitor analysis and post-processing of the 3D-mode proved to be advantageous.
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PURPOSE: Quantification of expected savings of work load and personnel costs after implementation of a digital infrastructure in an ultrasound division of a radiology department. MATERIALS AND METHODS: The work flow of an ultrasound examination was simulated by means of a computer model. After validation, the computer model was modified to represent a work flow with PACS, electronic patient record, and automatic scheduling. The simulation results of work load, equipment utilization, and personnel costs were compared for both scenarios. RESULTS: The total number of work steps was reduced from 29 in the conventional scenario to 14 work steps in the scenario with digital infrastructure. The work load of administrative activities decreased by 89 % whereas the work load of activities directly related to the ultrasound examination remained unchanged. The productive personnel costs declined from euro; 24 to euro; 16 per examination. The gross labor costs declined from euro; 33 to euro; 20 per examination. Given unchanged equipment and number of patients, the required number of physicians can be reduced from 3 to 2 and that of technicians from 2 to 1 by use of a digital infrastructure. CONCLUSION: A digital infrastructure possesses a great potential for efficiency provided that it is implemented comprehensively and the work flow is adapted utilizing the capabilities of automation in all work processes.
PURPOSE: To report our experience with flexible applicators in radiofrequency ablation (RFA) of hepatic tumors. MATERIALS AND METHODS: In 6 liver tumors in 6 patients, a flexible RFA-applicator system (RITA StarBurst FLEX, RITA Medical Systems, Mountain View, CA, USA) was placed under CT guidance. The Seldinger technique with an 11G access system (RITA StarBurst Access) was used to place the application system into the liver. Before and within a week after the ablation, all tumors were investigated with contrast-enhanced MRI. RESULTS: The Seldinger technique accommodated the placement of a thin 17.5-gauge needle for the initial puncture, enabling easy adjustment of the position of the needle. The flexible applicator of the RFA system could be placed in 4.5 (+/- 1.8) minutes on average. CONCLUSION: Flexible applicators facilitate CT-guided RFA and can be placed using the Seldinger technique.
PURPOSE: To assess and quantify the image quality at two dose levels for an amorphous Silicon (a:Si) Cesium Iodide (CsI) flat panel system compared with a direct amorphous Selenium (a:Se) digital radiography system. MATERIAL AND METHODS: A contrast detectability test was performed employing the CDRAD-phantom at mAs-values leading to approximately equal phantom entrance doses of 41.4, 57.9, 75.1 and 120.8 micro Gy for the a:Se and 39.9, 58.4, 75.6 and 117.9 micro Gy for the CsI system. Images were presented to 4 independent observers. For quantitative comparison, the image quality figure (IQF) was calculated. Statistical analysis was performed using Pearson's correlation and the Wilcoxon test. A ROC-analysis was performed employing the TRG-phantom in a high- and a low-dose setting leading to entrance doses of 126.2 and 35 micro Gy for the direct, and 125.9 and 34.4 micro Gy for the indirect system. Statistical significance was evaluated using the Wilcoxon test. RESULTS: The flat panel a:Si digital system provided superior results compared with the a:Se drum digital system with respect to low-dose settings for CDRAD-phantom and ROC-analysis, ensuring a better image quality with respect to contrast and detail detectability. Higher-dose settings provided similar results for both systems. CONCLUSION: Image quality of a:Si flat panel digital radiography proved to be superior to a:Se drum digital radiography using low-dose settings. If the primary target is dose reduction indirect flat panel technology should be used.
In a patient with refractory ascites after right hemihepatectomy TIPS was created between the left hepatic vein and the left portal vein via a transjugular approach. The puncture was guided only by sonography from the epigastrium. Portosystemic pressure gradient was reduced from 28 to 7 mm Hg and ascites disappeared. This case shows that TIPS can be created with technical and clinical success after right hemihepatectomy as left hepatic vein to left portal vein shunt under sonographic guidance.
BACKGROUND/AIMS: Diagnosis of retinoblastoma is mainly based on indirect ophthalmoscopy, but additional imaging techniques are indispensable for the staging of the disease. A new high resolution magnetic resonance imaging (MRI) technique for the examination of the eye was evaluated. A new surface coil with a diameter of 5 cm allows a field of view of 60 mm with an in-plane resolution of 0.8 mm. We compared preoperative MRI scans with the histology after enucleation in 21 cases of retinoblastoma. Parameters studied were appearance of retinoblastoma, choroidal and scleral infiltration, extraocular extension, optic nerve infiltration, and vitreous seeding. RESULTS: All retinoblastomas could be visualised as hypointense to vitreous on T2 weighted images and slightly hyperintense to vitreous on plain T1 weighted images with a moderate enhancement after contrast application. Histology revealed seven cases with infiltration of the optic disc or optic nerve. Preoperative MRI scans depict juxtapapillary tumour masses, but it was impossible to differentiate between a juxtapapillary retinoblastoma, a prelaminar infiltration of the optic disc, or a just postlaminar optic nerve infiltration. In five of 14 cases with a proved tumour infiltration of the choroid, MRI scans showed an inhomogeneous contrast enhancement of the choroid in enhanced T1 weighted sequences beneath the retinoblastoma. Whether this sign is specific for a choroidal infiltration or is just an artefact remains unclear. High resolution MRI scans did not allow the exclusion of this form of intraocular tumour extension. All nine cases with proved vitreous seeding were not detected by MRI scans. None of these cases showed scleral infiltration or orbital tumour extension. Therefore, it is not possible to judge the rank of this technique in detecting orbital tumour growth. CONCLUSION: The new MRI technique is of limited value in visualisation of prelaminar or postlaminar infiltration of the optic nerve. Advanced choroidal infiltration might be visualised by contrast enhanced T1 weighted MRI scans, but the available spatial resolution did not allow the exclusion this critical form of tumour growth by MRI scans. Nevertheless, high resolution MRI with the new surface coil has superior contrast and spatial resolution compared to computed tomograph (CT) or other available imaging techniques. MRI cannot replace CT in detecting tumour calcification but with increasing experience with this new technique it should be possible to renounce CT scans in the majority of cases of retinoblastoma.
Between 1987 and 2000, 111 patients with epidermoid anal cancer (T1-T4 Nx M0) were assigned to primary simultaneous radiochemotherapy (RCT) with a radiation dose of 45 Gy, performed either as a split course with 2-Gy single fractions (schedule A, 1987-1996, n = 65 patients) or continuously with fractions of 1.8 Gy (schedule B, 1996-2000; n = 38 patients). The chemotherapy consisted of continuous infusions of 5-fluorouracil (5-FU; 800/1,000 mg/m(2)/day, on 4/5 consecutive days, during weeks 1 and 5) together with one (schedule A) or two (schedule B) short infusions of mitomycin C (10 mg/m(2)) during the first course of 5-FU. Associations between clinical outcome and various prognostic factors were assessed in 103 patients who completed these schedules. For both patient groups combined, 5-year local control rate was 67% and 5-year survival rate 71%. Advanced tumor stage, size, and nodal status significantly decreased the 5-year local control rate as well as the overall treatment time (OTT) >41 days (58% for OTT >41 days vs. 79% for OTT < or =41 days; p = 0.04). However, we did not find a correlation with the prescribed radiotherapy schedule (A or B). In conclusion, in patients with anal carcinomas treated with RCT with a radiation dose of 45 Gy, the predominant determinant of local control is the resulting OTT and not the administration schedule (split course or continuous radiotherapy).