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W Bautz

Publications and source records attributed to W Bautz.

At least 73 records · Page 4Linked to original sources
PubMed1999

[The morphological and functional diagnosis of the head-neck area with multiplanar spiral CT].

PURPOSE: To evaluate the improvement of multislice-spiral CT in the assessment of head and neck tumors. MATERIAL AND METHODS: 80 patients with suspected tumor in the head and neck region were examined with MSCT (Somatom Plus 4 VZ) after the administration of i.v. contrast material. Slice collimation was 4 x 1 mm with a pitch factor of 6. Additional multiplanar reformations were calculated in each case. RESULTS: The specific anatomy and pathways of tumor spread is difficult to demonstrate in cross-sectional imaging. Tumor infiltration of the base of the skull or the palate could be depicted or excluded on coronal MPR, additional coronal scanning was not necessary. The detection of pathologic lymph nodes was improved with MPR in 7 patients. DISCUSSION: The exact determination of tumor margins is mandatory for modern therapy concepts of limited surgery. High resolution datasets are basis for reformations in arbitrary planes, making additional coronal scanning not necessary. Functional imaging of the larynx and hypopharynx improve the diagnostic accuracy of CT, a short scan time is necessary to reduce motion artifacts. Conclusive assessment of tumor infiltration, lymphatic spread and functional alterations is improved with MSCT.

Contrast Media↗
PubMed1999

[Multiplanar spiral CT in the diagnosis of pancreatic tumors].

PURPOSE: Investigation of the capabilities of MSCT and its value for the staging of pancreatic carcinomas. METHODS: 50 Patients with suspected pancreatic carcinoma were examined with a biphasic multislice-spiral-CT protocol: slice collimation 4 x 1 mm, Pitch 3.5-4 mm. After administration of 120 ml contrast medium and 50 ml NaCl with a flow rate of 3.0 ml/s the examination was started with a delay of 40 s (pancreatic phase) and 80 s (portal venous phase). RESULTS: Multislice spiral CT allows the examination of the whole upper abdomen with nearly isotropic data sets. This is the premise for the optimal assessment of the tumor extent in all planes, excellent demarcation of the tumor against the adjacent vessels and organs and the demarcation of small peripancreatic lymph nodes. CONCLUSIONS: Multislice spiral CT and the use of interactive multiplanar reconstructions improve the staging of pancreatic cancer.

Administration, Oral↗
PubMed1999

[Image quality and radiation exposure in digital mammography with storage phosphor screens in a magnification technic].

PURPOSE: Comparison of image quality between digital phosphor storage plate mammography in magnification technique and a conventional film screen system regarding the special aspect of radiation exposure. MATERIALS AND METHODS: Radiograms of a RMI-mammography phantom were acquired using a conventional film screen system and two digital storage plate systems. Additionally, the radiograms of one digital system were post-processed emphasizing contrast and included in the comparison. RESULTS: The detectability of details in storage plate mammographies with magnification technique is almost equal to that of film screen mammographies. Thereby, lower radiation exposures were necessary using the digital systems. CONCLUSIONS: Based on these results, storage plate mammography in magnification technique is used in clinical routine at our institution. The correct parameters in image postprocessing are of elementary importance for detail detectability. Future studies must show, whether the lower radiation exposure in digital radiograms of the breast, revealing much higher background noise, will allow the same detail detectability as film screen mammographies.

Female↗
PubMed1999

[Dosage reduction in computed tomography by anatomy-oriented attenuation-based tube-current modulation: the first clinical results].

PURPOSE: To examine the feasibility of reducing exposition in CT examinations by applying a prototype device for tube current modulation with the image quality remaining unchanged. PATIENTS AND METHODS: The prototype device for tube current modulation was integrated into a Somatom Plus 4 CT scanner (Siemens). The method is based on anatomy-oriented modulation of the tube current. The attenuation of the X-ray beam by the patient's body was determined online, the tube current was adapted to changing anatomy after a delay of 180 degrees. In ten patients undergoing radiotherapy, four identical scans of the shoulder region were carried out with and without tube current modulation. For determining dose reduction, mAs product of both scans were compared. The evaluation of noise artifacts, low contrast detectability and overall image quality was performed by four radiologists in a blinded fashion. RESULTS: Patient doses could be reduced by 38% on an average. Scans with tube current modulation were superior to scans without it as to noise (75%), low contrast detectability (51%), artifacts (69%), and overall image quality (71%). CONCLUSIONS: A significant reduction in exposition during CT can be achieved by anatomy-oriented tube current modulation without image degradation.

Artifacts↗
PubMed1999

Contrast enhanced MRA of peripheral arteries with the automatic "floating table".

Magnetic resonance angiography (MRA) is increasingly used as a non-invasive alternative to digital subtraction angiography (DSA). Besides plain time-of-flight (TOF) and phase contrast (PC) MRA a new MRA technique using positive contrast agent has been introduced recently. A fast 3D gradient-echo sequence is applied to reach a significant reduction of measurement time for acquisition of the MRA within the first pass of the contrast agent, thereby avoiding venous overlap. A significant progress was yielded by MR systems allowing manual table movement for examination of the pelvis and the lower limbs in one examination with a single contrast agent bolus. However, in this case it is necessary to have a coworker in the examination room moving the table manually. In this paper we report a prototype system which allows automatic table movement ("floating table"). Using this novel system we examined a patient with an aneurysm of the abdominal aorta and peripheral arterial occlusive disease (PAOD). Diagnostic results of contrast enhanced MRA and DSA were equivalent. In summary, the automatic floating table system introduced in this paper allows comfortable non-invasive examination of pelvic and lower limb arteries. The value of this technique in comparison to DSA has to be determined in future studies.

Arterial Occlusive Diseases↗
PubMed1999

Gd-BOPTA: "the MRA contrast agent of choice"?

Gd-BOPTA is a new positive MR contrast agent for intravenous application. In comparison to other gadolinium-chelates it has a nearly two-fold increased relaxivity due to weak protein binding with plasmatic macromolecules. In the papers published yet it has been evaluated to be useful for liver imaging. The purpose of this study was to evaluate, whether Gd-BOPTA is suited as an "magnetic resonance angiography (MRA) contrast agent". We examined four patients (aortic dissection, carotid artery stenosis, portal vein stenosis, exclusion of subclavian artery stenosis) with Gd-BOPTA with a dosage of 0.05 mmol/kg body weight. Furthermore, peripheral MRA of the pelvis and lower extremities was acquired in two healthy volunteers comparing 0.1 mmol Gd-DTPA/kg with 0.1 mmol Gd-BOPTA/kg. There was a delay of one week between the Gd-DTPA and the Gd-BOPTA examinations. In another volunteer Gd-BOPTA was reduced to 0.05 mmol/kg. The patient examinations revealed sufficient quality comparable with Gd-DTPA examinations despite of reduced dosage. In the volunteers Gd-BOPTA proved to be superior especially in the delineation of small pedal arteries which is important for surgical planning. These preliminary results demonstrate the potential of Gd-BOPTA to become a useful contrast agent for MRA. Its efficacy for this purpose has to be evaluated in future prospective studies.

Aortic Valve Stenosis↗
PubMed1998

Low-field magnetic resonance imaging of the pelvis in patients with anal dynamic graciloplasty: initial experience.

The aim of this study was to determine whether low-field magnetic resonance (MR) imaging can safely and accurately depict inflammatory changes in patients with anal dynamic graciloplasty, in whom high-field MR imaging is contraindicated and ultrasonography and computed tomography are inadequate. A 0.2-T field-strength MR examination was performed in six patients with anal dynamic graciloplasty malfunction in whom reoperation was contemplated. The following sequences were applied: T2-weighted turbo spinecho with fat saturation, T1-weighted conventional spin-echo, and contrast-enhanced T1-weighted conventional spin-echo with fat saturation. Results indicated that none of the patients experienced relevant discomfort, pacemaker malfunction, or electrode dislocation with low-field MR imaging. Inflammatory pelvic changes were visualized in four patients and atrophy of the transposed gracilis muscle in another. Surgery was thus avoided in the four, who underwent conservative treatment for their pelvic inflammation. It was concluded that these preliminary results demonstrate the feasibility of MR imaging with a low field strength in patients with anal dynamic graciloplasty. In such patients, in whom diagnostic imaging had been problematic, the potential for safe and accurate visualization will be a boon to treatment planning.

Adult↗
PubMed1998

[Pelvic wall recurrence of cervix carcinomas. Combined surgical-radio-chemotherapeutic procedure (CORCT)].

PURPOSE: The prognosis of patients with pelvic wall recurrences after primary therapy of cervical cancer is bad. In selected patients treated exclusively by surgery as primary therapy the 5-year survival rate was between 5 and 25%. Additionally the combination of operation and radiotherapy (CORT) improved the survival so far. We developed a new concept for the treatment of pelvic wall recurrences. This concept includes the combination of radical surgery, interstitial radiation and chemotheray--CORCT (combined operative- and radiochemotherapy). PATIENTS AND METHODS: After radical surgery, interstitial HDR (Ir-192) brachytherapy in afterloading technique (2.5 Gy, 2 fractions/day in 5 days) was performed. Additionally a chemotherapy with cisplatin 25 mg/m2/day in 5 days and 5-fluorouracil 1000 mg/day in 5 days was applicated. RESULTS: After combined operative- and radiotherapy 3 of 3 patients died after treatment within 8 months (median) because of distant metastases. After additive radiochemotherapy 3 of 4 patients had no evidence of disease (NED) after a follow-up period of 14 (12 to 30) months. CONCLUSION: The first treatment results of the new designed combined operative- and radiochemotherapy concept (CORCT) led us to expect an improvement of the prognosis of patients with recurrences of cervical cancer at the pelvic wall.

Adult↗
PubMed1998

Virtual cisternoscopy of intracranial vessels: a novel visualization technique using virtual reality.

This paper introduces a different visualization method which we call "virtual cisternoscopy" using 3D MRA data sets. Virtual cisternoscopy uses well known tools, such as perspective volume rendering (pVR), fly-through techniques, and interactive visualization and combines them to a new approach featuring motion to resolve spatial relationships of intracranial vessels and vascular malformations. With a dedicated flight protocol extraluminal topography of intracranial arteries was analyzed using pVR. For evaluation of difficult vascular malformations extraluminal views are necessary. Therefore, movies of pVR views were produced simulating virtual tracks of neurosurgical flexible endoscopes, by flying around the intracranial vessels and vascular malformations within the cisterns. Endoluminal views were acquired additionally for precise evaluation of cases with complex vessel topography. Two healthy volunteers and three patients were examined. Comparing MIP and pVR images relevant advantages of pVR were found, such as depth information, perspective, lighting, and color. In contrast to MIP and source images of the MRA data set, virtual cisternoscopy of an aneurysm of the left middle cerebral artery demonstrated clearly an early origin of an artery in the region of the aneurysm neck/sac. In this case only virtual cisternoscopy led to the correct therapeutical decision. In a newborn, the type of a vein of Galen aneurysmal malformation could only be evaluated reliably by means of virtual cisternoscopy. The third case of a patient with a clipped aneurysm was evaluated more easily with virtual cisternoscopy than with DSA. In conclusion, virtual cisternoscopy may improve the pretherapeutic visualization of intracranial vascular malformations.

Adult↗
PubMed1998

[Postoperative pulmonary torsion and hemorrhagic lung infarct--report of a case].

Lung or lobe torsion may occur after thoracic surgery, chest trauma, pneumothorax, pneumonia or even spontaneously. Lung infarction is a possible complication. The characteristic radiological signs on plain radiographs are opacification and/or displacement of lobes and hilus structures. CT-signs of haemorrhagic infarction are opacification and multiple punctate gas accumulations. The bronchus could be interrupted at the level of the torsion ("bronchus-cutoff").

Aged↗
PubMed1998

[What is the role of Doppler color sonography associated with echo-signal enhancing levovist in complementary breast diagnosis?].

At the women's hospital of the University of Erlangen we performed a prospective clinical study to evaluate the use of color Doppler imaging supported by the new echo contrast agent Levovist in comparison to clinical examination, B-mode sonography, mammography, and MRI. In 40 patients the sensitivity and specificity of each method was estimated in predicting the dignity of palpable or mammographically detectable tumors of the breast. Prior to and after administration of Levovist we recorded the number of vessels, the PI, RI, SD-ratio, and maximum flow velocity after correction of the angle. Color Doppler imaging of the tumor and the surrounding tissue was documented on video tape for five minutes after the administration of Levovist. We measured the time until an increase and decrease in color signal was detectable. The following sensitivities/specificities were found: clinical examination 57.1% (12/21)/73.7% (14/19), B-mode sonography 100% (21/21)/84.2% (16/19), mammography 100% (21/21)/89.5% (17/19) and MRI 92.3% (14/15)/78.6% (15/18). Without the contrast agent color Doppler imaging could not differentiate between malignant and benign lesions. There was no significant difference in the perfusion of benign and malignant tumors. However, after the administration of Levovist, there appeared to be a significant difference for SD-ratio. With a cut-off-level of 3.5 we found a sensitivity/specificity of 85% (17/ 20)/78.6% (11/14) for the Doppler method. There was a weak correlation between the time of appearance of the augmented Signal in color Doppler and the velocity of enhancement of the contrast agent in MRI (n = 24, r = 0.47, p = 0.02). Only with the use of a contrast agent was color Doppler ultrasound able to support the other methods in pre-operative differentiation of benign and malignant lesions in the breast.

Adult↗
PubMed1998

[Diagnosis and staging of lunate necrosis. A current review].

Recently, early diagnosis and staging of Kienböck's disease was mainly influenced by imaging techniques (CT and MRI). New findings led to the staging classification of Lichtman and Ross (1994) which is recommended in the following. MRI allows diagnosis of the reversible bone marrow edema (stage I), which often is equivocal in conventional radiography. High-resolution CT facilities a more precise imaging of later stages in Kienböck's disease including spongiosal sclerosis (stage II), fractures at the proximal pole (stage III A), and initial osteoarthrosis (stage IV). For therapeutic considerations, contrast-enhanced MRI is extremely useful in stages II and III A, whereas MRI is redundant in stages III B and IV. Carpal instability (stage III B) is sufficiently visualized using conventional radiograms exposed in the neutral position. This review article reveals the value and indications of CT and MRI.

Diagnosis, Differential↗