Biomedical subjects
C Düber
Publications and source records attributed to C Düber.
[Negative endoscopy and MSCT findings in patients with acute lower gastrointestinal hemorrhage. Value of (99m)Tc erythrocyte scintigraphy].
PURPOSE: To evaluate the clinical use of (99m)Tc red blood cell imaging (RBC imaging) in patients presenting with acute lower gastrointestinal (GI) bleeding and negative endoscopy and multislice computed tomography (MSCT) findings. PATIENTS AND METHODS: In 31 consecutive patients with acute lower GI bleeding in whom the endoscopy findings were negative or the procedure was not feasible, dual-phase MSCT of the abdomen was performed [collimation 4x1 mm (arterial phase), 4x2.5 mm (venous phase)]. MSCT was followed by a (99m)Tc red blood cell scan in patients in whom no active bleeding was visible by CT. Images were created within 24 h after administration of the tracer, depending on the clinical symptoms. The results of the imaging modalities were correlated with clinical course and surgical treatment. RESULTS: In 20 of 31 patients MSCT showed no active bleeding and a (99m)Tc red blood cell scan was performed. In 8 of 20 patients RBC imaging was also negative. Of these eight patients five were stable and did not require further diagnostic work-up; in the other three bleeding persisted and these patients required surgical treatment. In 12 of 20 patients active bleeding was demonstrated using a (99m)Tc red blood cell scan. Of 12 patients with positive RBC scintigraphy findings, 8 underwent surgery, where the site of bleeding was confirmed. CONCLUSION: In patients with acute lower GI bleeding with negative or nondiagnostic endoscopy or MSCT findings, (99m)Tc red blood cell imaging is a useful tool in an emergency algorithm, improving the overall bleeding detection rate.
[Main symptoms of acute abdomen].
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[Second reading of breast imaging at the hospital department of radiology: reasonable or waste of money?].
PURPOSE: To assess the effect of a second diagnostic reading of breast imaging at a university department of radiology. MATERIAL AND METHODS: The diagnostic reports of first readers from different private radiology practices and the reports of second readers from the university department of radiology were compared with the histological results (n = 214) and outcome of follow-ups for 4 years (n = 74) in 236 patients (mean age 55 years). BI-RADS categories were used for this purpose. The initial examinations had been performed because of symptoms (n = 117), early detection outside an organized screening program (n = 102), evaluations following breast cancer therapy (n = 13) and unknown primary tumors (n = 4). In addition, the number of complementary examinations and the influence of a second reading on patient management were evaluated. RESULTS: A total of 140 lesions were malignant and 148 were benign. Of the 288 lesions, 49 % were classified identically in the second reading; 36 % (79/217) of the lesions initially classified as BI-RADS 4 and 5 were downgraded to benign; and 41 % (29/71) of the lesions classified as BI-RADS 1 to 3 were upgraded as suspected of being malignant. The kappa value between the first and second readers was 0.34 with respect to each BI-RADS category separately and 0.18 with respect to categories 1 to 3 (benign) versus 4 and 5 (malignant). A second reading increased the sensitivity from 81 % (114/140) to 96 % (135/140) and the specificity from 30 % (45/148) to 78 % (116/148). Second readers detected 23 additional malignant lesions, changed two lesions correctly classified as malignant to benign categories and caused 6 additional false-positive findings. In all, 38 surgical biopsies could be prevented, one biopsy was erroneously delayed and three unnecessary excisional biopsies were initiated. In the study group, 49 MRI examinations revealed 5 additional malignant lesions and positively influenced surgical planning in 28 patients. In addition to these MRI examinations, 221 patients were examined using ultrasonography, 62 patients using complementary mammography, and 7 using galactography. CONCLUSION: The benefit of a second reading outweighs the expenditure.
[Quantification of pulmonary emphysema in multislice-CT using different software tools].
PURPOSE: The data records of thin-section MSCT of the lung with approx. 300 images are difficult to use in manual evaluation. A computer-assisted pre-diagnosis can help with reporting. Furthermore, post-processing techniques, for instance, for quantification of emphysema on the basis of three-dimensional anatomical information might be improved and the workflow might be further automated. MATERIALS AND METHODS: The results of 4 programs (Pulmo, Volume, YACTA and PulmoFUNC) for the quantitative analysis of emphysema (lung and emphysema volume, mean lung density and emphysema index) of 30 consecutive thin-section MSCT datasets with different emphysema severity levels were compared. The classification result of the YACTA program for different types of emphysema was also analyzed. RESULTS: Pulmo and Volume have a median operating time of 105 and 59 minutes respectively due to the necessity for extensive manual correction of the lung segmentation. The programs PulmoFUNC and YACTA, which are automated to a large extent, have a median runtime of 26 and 16 minutes, respectively. The evaluation with Pulmo and Volume using 2 different datasets resulted in implausible values. PulmoFUNC crashed with 2 other datasets in a reproducible manner. Only with YACTA could all graphic datasets be evaluated. The lung volume, emphysema volume, emphysema index and mean lung density determined by YACTA and PulmoFUNC are significantly larger than the corresponding values of Volume and Pulmo (differences: Volume: 119 cm(3)/65 cm(3)/1 %/17 HU, Pulmo: 60 cm(3)/96 cm(3)/1 %/37 HU). Classification of the emphysema type was in agreement with that of the radiologist in 26 panlobular cases, in 22 paraseptalen cases and in 15 centrilobular emphysema cases. CONCLUSION: The substantial expenditure of time obstructs the employment of quantitative emphysema analysis in the clinical routine. The results of YACTA and PulmoFUNC are affected by the dedicated exclusion of the tracheobronchial system. These fully automatic tools enable not only fast quantification without manual interaction, but also a reproducible measurement without user dependence.
[MDCT after balloon kyphoplasty: analysis of vertebral body architecture one year after treatment of osteoporotic fractures].
PURPOSE: To evaluate the value of MDCT in the monitoring of vertebral body architecture after balloon kyphoplasty and observe morphological changes of the vertebral body. MATERIAL AND METHODS: During a period of 26 months, 66 osteoporotic fractures of the vertebral bodies were treated with percutanous balloon kyphoplasty. The height of the vertebral body, width of spinal space, sagittal indices, kyphosis und COBB angle, and cement leakage were evaluated by computed tomography before and after treatment and in a long-term follow up. Statistical analysis was performed by calculating quantitative constant parameters of descriptive key data. In addition, parametric and distribution-free procedures were performed for all questions. RESULTS: After kyphoplasty, the treated vertebral bodies showed a significant gain in the height of the leading edge (0.15 cm; p < 0.0001) and in the central part of the vertebral body (0.17 cm; p < 0.0001). The height of the trailing edge did not change significantly. A corresponding gain in the sagittal index was found. The index remained stable during follow-up. Treated vertebral bodies as well as untreated references showed a comparable loss of height over the period of one year. The shape of the vertebral bodies remained stable. In comparison to these findings, treated vertebral bodies showed a reduced loss of height. A significant change in kyphosis und the COBB angle was noted. In total, pallacos leakage was detected in 71 % of cases. CONCLUSION: MDCT is an accurate method for evaluating vertebral body architecture after treatment with balloon kyphoplasty. Morphological changes in the vertebral bodies, and complications such as pallacos leakage and progression of osteoprosis can be accurately documented. The significant increase in the vertebral body height after treatment is closely correlated with a gain in the sagittal index and reduced kyphosis and COBB angle.
Diagnostic evaluation of magnetic resonance imaging with turbo inversion recovery sequence in head and neck tumors.
The clinical outcome of patients with head and neck cancer depends on many factors such as tumor size, metastatic involvement and angioarchitecture of the tumor. The correct staging of tumor extension, presence of cervical lymph node metastases and evaluation of vascular infiltration are essential diagnostic steps before treatment. The aim of this study was to evaluate the accuracy of turbo inversion recovery magnitude (TIRM) magnetic resonance imaging (MRI) in the diagnosis of head and neck tumors with special attention to tumor size and tumor spread according to the current TNM classification. TIRM sequence with short T1 relaxation and long TE (echo time) improves imaging contrast because of the increased T1-weighting and the inherent fat suppression. In a prospective clinical study, 32 patients underwent preoperative MRI. Diagnosis was confirmed histologically in all cases. Scanning was performed on a 1.0-T unit applying TIRM as well as T1- and T2-weighted turbo spin echo (TSE) sequences. In all sequences, tumor size was overestimated due to reactive inflammatory changes surrounding the tumor tissue. The least overestimation was documented on TIRM and post-contrast T1 TSE. The highest values of relative tumor signal intensities were obtained in TIRM (3.5+/-0.9) and T2 TSE (3.5+/-0.8) followed by post-contrast T1 TSE (1.6+/-0.7) and pre-contrast T1 TSE (1.2+/-0.3). Due to the inherent fat suppression, tumor delineation was most obvious in TIRM. In patients with suspected cancer of the head and neck, TIRM should be considered as a standard and a diagnostically relevant sequence in the MRI staging protocol.
[Classification and treatment of endoleaks after endovascular treatment of abdominal aortic aneurysms].
This article describes the classification of endoleaks after endovascular treatment of abdominal aortic aneurysms, thereby summarizing the most important problems of this endovascular technique. The correct classification of endoleaks is a prerequisite for interdisciplinary discussion. It is indispensable for professional reporting of the pathological findings and for the decision making as to the adequate treatment of endoleaks. Irrespective of the types of stent graft and property of the material, five endoleak types are defined in the literature: leakage at the anchor sites (type I); leakage due to collateral arteries (type II); defective stent grafts (type III); leakage due to porosity of the graft material (type IV); and endotension (type V). The causes of endoleaks are discussed and treatment options are reviewed for the diverse pathologic findings.
[Direct percutaneous radiologic jejunostomy (PR) and duodenostomy: a retrospective analysis].
PURPOSE: To present our experience with direct percutaneous radiologic duodenostomy and jejunostomy (PRJ) for alimentation. MATERIALS AND METHODS: A retrospective study identified 24 patients who had undergone percutaneous jejunostomy or duodenostomy guided by CT and fluoroscopy over a period of 9 years. Whenever possible, the jejunum was inflated with a 5 French diagnostic catheter and jejunopexy was performed using Cope anchors (T-fasteners). A 12 to14 French locking pigtail drain was inserted for alimentation. In 8 patients, percutaneous direct jejunostomy was performed using only fluoroscopy. In 9 patients, both CT and fluoroscopy were used to guide the jejunostomy. In all 7 patients who underwent duodenostomy, a combination of CT and fluoroscopy was used. The reports were reviewed for complications and the technical success rate. The technical success rate was determined. RESULTS: Percutaneous radiologic jejunostomy was attempted in 17 patients and failed in 5 patients. PRJ was successful in all 8 procedures guided by fluoroscopy and in 4 of 9 procedures guided by CT and fluoroscopy. Direct percutaneous duodenostomy guided by CT and fluoroscopy was successful in all 7 cases. There were no procedure-related laparotomies and no mortality related to the jejunostomy. Minor complications were infection of the abdominal wall (n = 1), lingering pain requiring a new jejunostomy (n = 1) and aspiration because of persistent reflux (n = 1). CONCLUSION: PRJ is a safe procedure even in critically ill patients. It is technically difficult and may fail if the jejunum cannot be distended. Percutaneous radiologic duodenostomy and jejunostomy are recommended for prolonged alimentation of malnourished patients following esophageal or gastric surgery.
[Correlation of duplex sonographic stenosis grading by means of cross-sectional analysis and MR-tomographic blood volume flow quantification in unilateral stenosis of the internal carotid artery].
PURPOSE: Correlation of duplex ultrasonographic grading of unilateral internal carotid artery (ICA) stenosis and ICA blood volume flow (BVF) quantification. MATERIALS AND METHODS: Using a 2D cine phase-contrast MR technique, 62 patients with unilateral ICA stenosis at the level of the bifurcation between 50 % and 98 % and 20 age-matched normal controls were examined. BVF was measured in the stenosed ICA. Ultrasonographic grading of stenoses was based on cross-sectional duplex sonography (color Doppler flow imaging [CDFI], real-time compound imaging) and compared to the changes in BVF in the stenosed ICA. RESULTS: There was no statistically significant difference in BVF in stenoses of the ICA up to 70 % and in normal controls. ICA stenoses greater 70 % began to be hemodynamically relevant. With increasing stenosis, a decrease in BVF in the ipsilateral ICA was determined with a high and linear correlation of r = - 0.83. Normal controls showed a BVF in an ICA of 247.0 +/- 32.0 ml/min, patients with 70 % stenosis a mean BVF of 225.3 +/- 32.2 ml/min (P = 0.4) without significant reduction, patients with 80 % stenosis a significant reduction of BVF to a mean flow of 184.0 +/- 53.8 ml/min (P < 0.005), patients with 90 % stenosis a reduction of the mean BVF in the stenosed ICA to 84.6 +/- 41.9 ml/min (P < 0.0005) and patients with stenoses > 95 % a mean BVF of only 26.0 +/- 4.0 ml/min (P < 0.0005). In patients with unilateral ICA stenosis greater than 81 %, a significant decrease of BVF in the stenosed ICA was documented. CONCLUSION: Comparison of ultrasonographic grading of unilateral ICA stenosis and BVF determination in patients with ICA stenoses demonstrate a high correlation between increase in the stenosis and decrease in the ipsilateral blood flow beginning at 70 % stenosis. ICA stenoses greater than 80 % are significantly hemodynamically relevant.
[Correlation of MRI and histopathology of bone marrow in patients with multiple myeloma].
PURPOSE: To compare MRI findings and histological plasmacellular infiltration of the bone marrow in patients with multiple myeloma (MM). MATERIAL AND METHODS: Twenty-four patients with different stages of MM underwent 1.5T MRI of the pelvic bone before iliac crest punch biopsy. Precontrast T1wSE and STIR and postcontrast (Gd-DTPA) T1wSE-fatsat were acquired using axial slices. Immediately after the biopsy, T1wSE was repeated to locate the biopsy canal. The corresponding region in the examination before punch biopsy was assessed for bone marrow involvement using a three-point score (0: negative, 1: suspect, 2: definite). RESULTS: Two patients were not included because the location of the biopsy canal was unclear. Of 7 patients without histological plasmacellular infiltration, MRI was false positive in one case (suspect). Of 15 patients with histological infiltration, MRI was positive in 10 cases (4 suspect, 6 definite). The T1wSE was positive in 9 cases, STIR in 8 cases, and postcontrast T1wSE-fatsat in 7 cases. In 10 of the 15 patients, the infiltration was histologically graded as low (5 - 20 % of bone marrow). In this group, MRI was only positive in 5 cases (3 suspect, 2 definite). Of five patients with the infiltration histologically graded as high (> 20 % of bone marrow), MRI was positive in all cases (1 suspect, 4 definite). CONCLUSION: Only advanced bone marrow infiltration in MM can be reliably detected by MRI. None of the used sequences proved to be significantly superior or inferior.
[Localization of bleeding using 4-row detector-CT in patients with clinical signs of acute gastrointestinal hemorrhage].
PURPOSE: There is no gold-standard regarding the diagnostic work-up and therapy of an acute gastrointestinal (GI) hemorrhage. In most cases endoscopy provides the diagnosis but in a low percentage this modality is not feasible or negative. Purpose of this study was to evaluate the role of multi-phase Multi-Slice-Computertomography (MSCT) as a modality to diagnose and locate the site of acute GI hemorrhage in case of unfeasible or technically difficult endoscopy. MATERIALS AND METHODS: 58 patients, presenting with clinical signs of lower GI hemorrhage, were examined through a 24-month period. Preliminary endoscopy was either negative or unfeasible. Images were obtained with a four-detector row CT with an arterial (4 x 1 mm collimation, 0.8 mm increment, 1.25 mm slice width, 120 kV, 165 mAs) and portal venous series (4 x 2,5 mm collimation, 2 mm increment, 3 mm slice width, 120 kV, 165 mAs). Time interval between endoscopy and CT varied between 30 minutes and 3 hours. The results of the MSCT were correlated with clinical course and surgical or endoscopical treatment. RESULTS: 20 of the 58 patients (34 %) undergoing MSCT had a bleeding site identified, thus providing decisive information for the following intervention. In case of a following therapeutic intervention there was 100 % correlation regarding the bleeding site. In 38 of the 58 patients (66 %), a bleeding site was not identified by MSCT. Twenty of these 38 patients (53 %) were stable and required no further treatment. In 18 of these 38 patients further interventional therapy was required due to continuing hemorrhage and in all of those patients the bleeding site was detected by intervention. CONCLUSION: Compared to other diagnostic methods MSCT is a fast, widely-available and low-risk technique for the localization of active GI hemorrhage. The clinical use seems to be justified since in more than one third of the patients, MSCT demonstrates the site of bleeding and provides decisive information for further interventional therapy. Concerning those patients, in whom MSCT is negative (38 out of 58 patients), only every second patient requires any additional diagnostic work-up.
[Whole-body MSCT of patients after polytrauma: abdominal injuries].
PURPOSE: The goal of this retrospective study was to evaluate the spectrum of abdominal injuries and the reliability of computed tomography-based diagnosis in patients after polytrauma. MATERIAL AND METHODS: CT findings and clinical reports for 177 patients after polytrauma were evaluated with regard to abdominal injuries. Clinical patient reports at the time of discharge from the hospital were utilized as the standard of reference. Abdominal injuries resulting from an accident, frequent additional traumas and following therapeutic procedures were recorded. In the case of discrepancies in the reports, the CT scans were viewed retrospectively. RESULTS: In 30 out of 177 patients, 42 abdominal injuries were detected. 69 % of the injuries were caused by traffic accidents while 31 % resulted from falls. Liver and spleen injuries were the most common. 50 % of the cases were treated surgically, and the other half of the cases underwent non-surgical conservative therapy. Massive chest traumas, pelvic injuries, cerebral traumas and injuries to extremities were commonly associated with abdominal injuries. Evaluation of the discrepancies in the clinical reports showed that injury to the pancreas and the small intestine were not successfully detected on CT, thus resulting in a false negative diagnosis. Early stages of organ parenchyma laceration were also initially misdiagnosed on CT. CONCLUSION: Contrast-enhanced whole-body MSCT is a reliable and rapid method for diagnosing abdominal injuries in patients after polytrauma. Only very few patterns of injury are not detected on CT. The appearance of fluid collection in the abdomen is an indicator of possible parenchyma injury and requires further evaluation in cases of clinically suspected organ trauma.
[Unilateral eyelid swelling after a simple nose blowing].
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Extracranial-intracranial arterial bypass surgery improves total brain blood supply in selected symptomatic patients with unilateral internal carotid artery occlusion and insufficient collateralization.
It remains controversial whether extracranial-intracranial (EC-IC) arterial bypass surgery leads to a significant increase in brain blood supply, allowing the reversal of regional cerebral hypoperfusion in symptomatic patients with occlusive cerebrovascular disease and hemodynamic impairment. The aim of the present study was to determine the effects of EC-IC bypass surgery on cerebral brain-supplying blood volume flow (BVF; ml/min) from a purely hemodynamic point of view, using 2D cine phase-contrast MR imaging. Twenty-five patients with symptomatic, unilateral internal carotid artery (ICA) occlusion and hemodynamic compromise received EC-IC arterial bypass surgery. All patients underwent quantitative BVF measurements of brain-supplying arteries preoperatively and postoperatively, including the direct BVF measurement in the established EC-IC bypass after surgery. Preoperatively, total brain BVF was reduced in comparison to normal controls (595 +/- 89 vs 663 +/- 49 ml/min; [mean +/- SEM]; p = 0.039). Mean BVF through the EC-IC bypass reached 84 +/- 32 ml/min (range: 14-177 ml/min), leading to a significant net increase in total BVF of 78 +/- 43 ml/min (range: 7-136 ml/min) when compared with BVF prior to surgery (p < 0.001), with resulting postoperative BVF reaching values obtained in normal controls. EC-IC arterial bypass surgery increases total brain blood supply, allowing restoration of local perfusion in hemodynamically compromised brain tissue in patients with symptomatic ICA occlusion.
[Long-term hemodynamic compromise in internal carotid artery dissection: quantitative blood volume flow evaluation using 2D Cine phase-contrast MR imaging].
PURPOSE: To use the magnetic resonance (MR) phase-contrast technique as a non-invasive method to determine blood volume flow in internal carotid artery (ICA) dissection, which has variable initial volume flow reduction and long term hemodynamic compromise. ICA dissection can lead to partial or complete recanalization or persistent occlusion, and strong clinical motivation exists for reliable assessment of the blood flow, in particular blood volume flow, in the carotid artery circulation after ICA dissection. MATERIALS AND METHODS: Blood volume flow in the carotid artery circulation was quantified in 28 patients with unilateral ICA dissection and 20 age-matched normal controls. Blood volume flow was measured in the ICAs and the common carotid arteries (CCAs) using 2D cine phase-contrast MR imaging. Final measurements were performed until after at least 6 months the hemodynamic compromise showed no changes by ultrasound and MRA. RESULTS: In long term follow up, 11/28 patients demonstrated remaining vessel occlusion, 10/28 partial and 7/28 complete recanalizations. Patients with ICA occlusion showed a significant contralateral volume flow increase (mean 56 %, p < 0.001) in comparison to normal controls. Patients with partial recanalization demonstrated volume flow rates between 24 ml/min and 188 ml/min in the dissected ICA and a less but significant (p < 0.001) increase in the contralateral volume flow. In patients with complete recanalization, normal volume flow conditions were found for both ICAs and CCAs. CONCLUSION: In ICA dissection, quantitative volume flow determination using 2D cine phase-contrast MR imaging is helpful in the initial assessment and long term follow-up of hemodynamic compromise. ICA dissection demonstrated a partial or complete recanalization in nearly (2/3) of the investigated patients and a persisting vessel occlusion in little more than (1/3). Compensatory contralateral increase in volume flow was found.
[Primary diagnostics of acute diverticulitis of the sigmoid].
AIM: The initial diagnostics of acute diverticulitis of the sigmoid should render the correct diagnosis as well as assisting in the decision on the options of conservative or surgical treatment by ruling out or demonstrating complications. At present, sonography or computed tomography (CT) are the two competing diagnostic options. This study was designed to demonstrate that sonography could be used as the method of choice. METHOD: 63 patients with clinical suspicion of acute diverticulitis of the sigmoid were examined initially by sonography or CT in a prospective study. RESULTS: Sonography and CT showed a 97 % sensitivity and specificity for reaching the accurate and clinically plausible diagnosis. As to the demonstration of complications of the disease, sensitivity and specificity were comparably high for both diagnostic methods. CONCLUSIONS: Sonography can compete with the more complex CT examination and therefore represents the recommended primary diagnostic procedure.
[Dynamic MRI of the bone marrow for monitoring multiple myeloma during treatment with thalidomide as monotherapy or in combination with CED chemotherapy].
PURPOSE: To quantify changes of bone marrow microcirculation in multiple myeloma (MM) using contrast enhanced dynamic MRI (dMRI) during thalidomide as antiangiogenic monotherapy or in combination with chemotherapy (cyclophosphamide, etoposide, dexamethasone). MATERIALS AND METHODS: The study includes 63 patients with refractory or relapsed MM, who underwent dMRI with high temporal resolution (T1w-turboFLASH) of the lumbar spine before and following treatment. The contrast uptake was quantified using a two compartment model with the output parameters amplitude and k (ep) (exchange rate constant). The evaluation considered the initial dMRI finding (pathological or non-pathological) and the clinical therapeutic response (response or no response). RESULTS: During monotherapy with thalidomide (n = 38), no significant changes of the dMRI parameters were found, even when considering the initial dMRI finding (positive n = 22) and the therapeutic response (responder n = 14). The combination with chemotherapy (n = 25) had a significant reduction of k (ep) (p = 0.01) in 18 patients with positive initial dMRI finding and therapeutic response. Reduction of the amplitude was seen in most cases, but in the end without any significance (p = 0.09). CONCLUSION: dMRI can quantify significant changes of bone marrow microcirculation solely during treatment with thalidomide combined with chemotherapy, not with thalidomide alone.