Search PubMed⌕ Search

Biomedical subjects

W Bautz

Publications and source records attributed to W Bautz.

At least 37 records · Page 2Linked to original sources
PubMed2003

Experimental investigations of image quality in X-ray mammography with a conventional screen film system (SFS) and a new full-field digital mammography unit (DR) with a-Se-detector.

PURPOSE: Determination of image quality of a new digital mammography system with an a-Se-detector. MATERIAL AND METHOD: Radiograms of the Wisconsin Mammographic Random Phantom, Modell 152 A (Radiation Measurements Inc., Wisconsin) were acquired using a conventional film screen and a digital system. RESULTS: With the conventional film screen system there were detected 191/a 38.2 and with the digital mammography 219/a 43.8 of 225 possible details. CONCLUSION: Based on these results there is the possibility to replace the conventional film screen system by the digital mammography with a-Se-detector--this has to be confirmed in further clinical trials.

Breast Neoplasms↗
PubMed2003

[Film-screen mammography versus digital storage plate mammography: hard copy and monitor display of microcalcifications and focal findings--a retrospective clinical and histologic analysis].

PURPOSE: A retrospective clinical-histological study to determine the diagnostic accuracy of mammography using conventional screen-film cassettes (hard copy), high-resolution digital phosphor storage plates (hard copy) and monitor display (soft copy) for microcalcifications and focal lesions (BI-RADS (TM) category 4 or 5). MATERIALS AND METHODS: From April to November 2001, 76 patients underwent conventional film-screen mammography and, after diagnosis and preoperative wire localization, digital mammography with the same exposure parameters. Five investigators retrospectively determined the diagnosis after the operation from randomly distributed mediolateral views (hard-copy reading) and from the monitor display (soft-copy reading). These results were correlated with the final histology. RESULTS: The accuracy of conventional screen-film mammography, digital mammography and monitor-displayed mammography was 67%, 65% and 68% for all findings, (n = 76), 59%, 59% and 68% for microcalcifications (n = 44) and 75%, 72% and 63% for focal lesions (n = 32). The overall results showed no difference. CONCLUSION: Our findings indicate equivalence of conventional screen-film mammography, high-resolution digital phosphor storage plate mammography and monitor-displayed mammography.

Adenocarcinoma↗
PubMed2003

[First experiences with a new vacuum-assisted device for breast biopsy].

OBJECTIVE AND METHODS: Stereotaxic and sonographically guided vacuum biopsies are standard methods in interventional breast procedures. We report about the newly developed sonographically guided and vacuum-assisted VacuFlash (VF) method for breast biopsy. In comparison to the Mammotome system, all components for vacuum biopsy are integrated in the hand-held gun of the VF biopsy system. Our first preliminary results in 5 patients are reported. RESULTS: VF was performed in five patients with a nonpalpable, sonographically detectable lesion. The histopathological examination diagnosed a fibroadenoma in 4 patients and established unremarkable breast parenchyma in 1 patient. Subsequent sonography immediately after the biopsy revealed that 3 of the 5 lesions were completely removed. CONCLUSION: The VF biopsy system is a new, technically perfected and applicable diagnostic method. Its costs, risks and accuracy have to be compared with high-speed core cut biopsy, hand-held Mammotome system and open surgical biopsy. Indications for the VF-biopsy are lesions that are too small, superficial or deep for conventional core biopsy as well as abnormalities where wide sampling is considered important. Complete removal can only be expected when the lesion is small and plays a secondary role in a diagnostic process. High-speed core cut biopsy remains the standard procedure in percutaneous breast interventions to clarify sonographically detected breast lesions.

Biopsy↗
PubMed2003

[Improvement of the image quality of MSCT of the pelvis with a raw data-based, multidimensional filter].

PURPOSE: To evaluate the potential of raw data-based multidimensional adaptive filtering (MAF) by determining its effects on image noise and image quality in multi-slice spiral CT (MSCT) of the pelvis. MATERIALS AND METHODS: Fifty patients with rectal and bladder cancer were examined with MSCT using a high-resolution protocol. Reconstructions were performed with dedicated reconstruction software and a standard algorithm, both without and with MAF, with four different modification fractions selected from 5 % to 20 %. The noise was measured at six anatomic sites of the pelvis. Image quality and image noise were rated on a 5-point-scale. RESULTS: Modification fractions of 15 % (15 % MAF) and 20 % (20 % MAF) significantly reduced the noise level at all measurement points in comparison with lower modification fractions (p < 0.05). Overall quality of the reconstructed images was rated better with 15 % MAF and 20 % MAF than with other modification fractions (p < 0.05). No further improvement of the image quality was observed by changing from 15 % MAF to 20 % MAF (p > 0.05). 15 % MAF achieved a mean noise reduction of 33 %. All examinations showed an improved visualization of the rectal wall and perirectal lymph nodes. CONCLUSIONS: MAF improves the image quality by reducing the noise level and by removing noise structures. This technique offers new perspectives to radiation dose reduction in CT.

Humans↗
PubMed2003

[Experimental investigations at the new digital mammographic system].

PURPOSE: Experimental investigations of a new digital mammography system. MATERIALS AND METHODS: The digital mammography system SenoScan (Fischer Imaging) is based on 4 charged coupled devices (CCD) (slot detector). The pixel size is 50 micro m, field of view 21 x 29 cm (2), effective quantum efficiency (DQE) (0) 50 %, spatial resolution 10 lp/mm, and memory depth 12 bit. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152 A (Radiation Measurements Inc., Wisconsin). The radiograms were acquired using the digital mammography system. RESULTS: The digital mammography detected 225 of 225 possible details. The surface dose was 6.95 mGy. CONCLUSIONS: These experimental results support the use of the digital mammography in practice. This has to be confirmed in further clinical trials.

Female↗
PubMed2002

[Indications and diagnostic sensitivity of CT and MRI in the otorhinolaryngology field].

Of all malignant tumors, 4-5% affect the head and neck region. Computed tomography (CT) and magnetic resonance imaging (MRI) provide the means for us to determine the precise extent and depth of infiltration of space-occupying lesions, detect submucosal growth, stage lymph nodes preoperatively, and thus facilitate better preoperative planning. Thinner collimations of sections and shorter examination times are possible with modern multilayer spiral CT. Two-dimensional and three-dimensional images can be calculated from the volume specifications to assess the skull base (coronal and sagittal sections) and the midline crossover of tumors as well as staging of lymph nodes (coronal section). Examination of laryngeal and hypopharyngeal function as well as determination of tumor perfusion are also possible. Detection of tumors that do not absorb any contrast medium (approximately 15%) is more difficult with CT. In addition to providing a high degree of tissue contrast, MRI makes it possible to directly acquire images in any number of planes. In contrast to CT, metallic artefacts hardly come into play. Infiltration of the dura and the cerebrum can be depicted better with MRI than with CT. The long examination time with MRI carries the risk of movement artefacts. In the head and neck region, it is important to suppress fat in T2-weighted sequences and in T1-weighted sequences after administration of contrast media. Inflammations in the head and neck region are only exceptionally clarified with CT or MRI. It is imperative that CT be performed before functional endoscopic operations of the paranasal sinuses. Further indications for CT and MRI in cases of inflammation are the diagnosis of retrotonsillar and parapharyngeal abscesses and ensuing complications as well as the diagnosis of osteomyelitis. Since conventional sialography is contraindicated in acute inflammation in sialolithiasis, magnetic resonance sialography can be employed.

Humans↗
PubMed2002

[CT and MRI of the petrous bone].

Diseases of the petrous bone should now be diagnosed by means of high-resolution multislice spiral computed tomography (MSCT) and/or magnetic resonance imaging (MRI). The first step in the process of diagnosis, however, must be conventional X-ray photographs (according to Schüller, Mayer, Stenvers) for screening purposes, because of the high cost of the other procedures mentioned. Because of the excellent imaging of bone structures with MSCT, this technique is especially suitable for the diagnosis both of acquired pathologies and of congenital abnormalities of the external auditory meatus, the middle ear and the mastoid, of trauma-induced pathologies of the entire petrous bone, and of osteogenic diseases. MRI is the method of choice for examination of the labyrinthine system, the interior auditory meatus and the cerebellopontine angle because it gives much the best depiction of soft tissue. Sometimes when questions remain unsolved after computed tomography (CT) examination of the middle ear MRI can be applied to complement CT, and it can yield additional information. Lesions affecting the apex of the petrous pyramid should be examined by MRI. High-resolution CT through the bone window and thin-layer MRI are both components of the presurgical diagnosis before cochlear implant (CI) surgery. For postoperative monitoring a conventional transorbital X-ray of the petrous bone is sufficient; CT is indicated only in complicated cases, and MRI is absolutely contraindicated after CI.

Artifacts↗
PubMed2002

[Value of CAD systems].

PURPOSE: Early detection of breast cancer enables for the reduction of mortality. The purpose of this article is to describe commercially available systems for computer-aided diagnosis (CAD) for mammograms and to analyze their diagnostic potential and utility. MATERIALS AND METHODS: Up to now, there are three CAD-systems available, the Image Checker M 1000 (R2-Technology, USA), the Second Look-system (CADx Medical Systems) and the Mammex TR (Scanis Inc., USA). Most of the present studies are done with the R2-system. The mammographies have been digitalized secondarily. Different algorithms recognized microcalcifications and masses. The connection between full field digital mammography systems and DICOM-networks is possible. RESULTS: In retrospective and one large prospective study with 12.860 patients it could be shown that sensitivity of the investigator with CAD could be improved up to 19%, microcalcifications are yielded with CAD in 100%, masses in up to 80%. CONCLUSION: Double-reading with CAD-systems can increase early breast cancer detection effectively. Regarding the development of full field digital mammography we are looking forward to further innovations.

Algorithms↗
PubMed2002

[Do tissue marker clips after sonographically or stereotactically guided breast biopsy improve follow-up of small breast lesions and localisation of breast cancer after chemotherapy?].

PURPOSE: We wanted to determine if tissue marker clips after sonographically or stereotactically guided breast biopsy improve the follow-up of small breast lesions classified BI-RADS 4/5 and the localisation of breast cancer (TNM stage 2 or 3) after neoadjuvant chemotherapy. MATERIAL AND METHODS: Prospective analysis was performed of 108 breast lesions 1 cm or smaller mammographically classified as BI-RADS 4/5 and 14 breast lesions larger than 2 cm mammographically classified as BI-RADS 5. 33 of the 108 breast lesions 1 cm or smaller underwent sonographic core cut breast biopsy (group 1) and 75 stereotactic vacuum-assisted breast biopsy (group 2). All 14 lesions greater than 2 cm were stereotactically vacuum-assisted breast biopsied (group 3). The centre of the lesion was marked by a clip after the biopsy. Mammographies were performed in all patients of group 1 and 2 with a histologically benign finding (n = 31, n = 69, respectively) and in all patients of group 3 directly after clip placement and after 6 and 12 months. Clip localisation and possible divergence from the original position were verified by a grid. RESULTS: Two patients of group 1 and 6 patients of group 2 had breast conservative surgery (BET) because of the histological diagnosis of a ductal carcinoma in situ or invasive breast cancer. The tissue marker clips of the remaining 31 patients of group 1 and 69 patients of group 2 diverged with a mean value of 0.4 cm (standard deviation +/- 0.23 cm; range 0.1 cm to 0.9 cm) from their placement position after 6 months. After 12 months the marker clips deviated with a mean value of 0.4 cm (standard deviation +/- 0.21 cm; range 0.1 cm to 0.9 cm) in 94 patients and 0.8 cm (standard deviation +/- 0.25 cm; range 0.1 cm to 0.9 cm) in 6 patients from their original location. No tumour progression of the benign lesions in group 1 and 2 was diagnosed in follow-up mammograms. In all patients of group 3 the tissue marker clips were the only possibility to localize the tumour after neoadjuvant chemotherapy as all other diagnostic methods showed inconsistent results. CONCLUSION: Positioning a tissue marker clip in the tumour centre seems to be reasonable after interventional biopsy of breast lesions of 1.0 cm or smaller and before neoadjuvant chemotherapy.

Antineoplastic Agents↗
PubMed2002

[VIBE with parallel acquisition technique - a novel approach to dynamic contrast-enhanced MR imaging of the liver].

PURPOSE: The VIBE (volume interpolated breath-hold examination) sequence in combination with parallel acquisition technique (iPAT: integrated parallel acquisition technique) allows dynamic contrast-enhanced MRI of the liver with high temporal and spatial resolution. The aim of this study was to obtain first clinical experience with this technique for the detection and characterization of focal liver lesions. MATERIALS AND METHODS: We examined 10 consecutive patients using a 1.5 T MR system (gradient field strength 30 mT/m) with a phased-array coil combination. Following sequences were acquired: T 2 -w TSE and T 1 -w FLASH, after administration of gadolinium, 6 VIBE sequences with iPAT (TR/TE/matrix/partition thickness/time of acquisition: 6.2 ms/ 3.2 ms/256 x 192/4 mm/13 s), as well as T 1 -weighted FLASH with fat saturation. Two observers evaluated the different sequences concerning the number of lesions and their dignity. Following lesions were found: hepatocellular carcinoma (5 patients), hemangioma (2), metastasis (1), cyst (1), adenoma (1). RESULTS: The VIBE sequences were superior for the detection of lesions with arterial hyperperfusion with a total of 33 focal lesions. 21 lesions were found with T 2 -w TSE and 20 with plain T 1 -weighted FLASH. Diagnostic accuracy increased with the VIBE sequence in comparison to the other sequences. CONCLUSION: VIBE with iPAT allows MR imaging of the liver with high spatial and temporal resolution providing dynamic contrast-enhanced information about the whole liver. This may lead to improved detection of liver lesions, especially hepatocellular carcinoma.

Adenoma↗
PubMed2002

[MR imaging of pancreatic lesions with Mn-DPDP. A histopathologic correlation].

PURPOSE: To examine the diagnostic accuracy of pancreatic lesions using mangafodipir-trisodium (Mn-DPDP) enhanced MR imaging. The imaging results were correlated with the histopathological results. MATERIAL AND METHODS: 40 patients with suspicion of pancreatic carcinoma were examined with MRI before and after i. v. administration of Mn-DPDP (Philips Gyroscan ACS NT 1.5 T, phased array body-coil: TSE T 2 with and without SPIR, TR 2000 ms, TE 120ms; FFE T 1 breathhold, TR 115 ms, TE 4.6 ms; MRCP, TR 6000 ms, TE 1200 ms; Teslascan i. v. 5 micromol Mn/kg; FFE T 1 breathhold SPIR, TR 140 ms, TE 4,6 ms). Two observers evaluated in consensus the number and characteristics of focal pancreatic lesions. The MR findings were correlated with histopathological findings retrospectively. RESULTS: The following lesions were found: adenocarcinoma (19), pancreatitis (8), adenocarcinoma within pancreatitis (3), insulinoma (2), hematoma (1), papillitis stenosans (1), signet ring cell carcinoma (1), metastasis of rectal carcinoma (1), papillary mesothelioma (1). In three patients there was no pathological finding. Mn-DPDP enhanced MRI showed a sensitivity of 100 % and a specificity of 56 %. CONCLUSION: Mn-DPDP enhanced MRI in conjunction with MRCP showed a high sensitivity for the detection of pancreatic lesions. However, the specificity is low, thus recommending Mn-DPDP enhanced MRI only as a complementary imaging method.

Ampulla of Vater↗
PubMed2002

[Galactoscopy--is it a new interventional method for breast diagnosis?].

Based on experimental studies with animals we examined 22 patients with pathological (bloody) nipple discharge by cytology, ultrasonography, galactography and the newly developed galactoscopy [Endoscopic-System EndoGnost(R) (Polydiagnost)]. The duct's cannula has an outer/inner diameter of 0.45 mm/0.36 mm and a working length of 30 mm, the endoscope a length of 1200 mm, adapted to a CCD-camera (2500 pixel). All patients underwent surgery and histo-pathological diagnosis. The best diagnostic results were received with galactoscopy (21/22). By using an additional cutter it is possible to obtain a histological sample for diagnosis endoscopically. Galactoscopy is an emerging technique and will expand the spectrum of interventional methods in breast diagnosis.

Biopsy↗
PubMed2002

[Experiences with phantom measurements in different mammographic systems].

PURPOSE: Determination of image quality between conventional film screen system, digital phosphor storage plate mammography (high resolution) and digital mammography. MATERIALS AND METHODS: Mammograms of the Wisconsin Mammographic Random Phantom, Model 152 A (Radiation Measurements Inc., Wisconsin) were acquired using a conventional film-screen system, a digital storage phosphor plate system and a digital system. RESULTS: Of 225 possible details, 191/a 38.2, 193/a 38.6, and 202/a 40.4 details were detected with conventional film-screen system, digital phosphor storage plate mammography and digital mammography, respectively. There was no significant difference (p < 0,058). The entrance surface air kerma was 9.64 mGy, 7.60 mGy and 7.02 mGy, respectively. CONCLUSIONS: Based on these results, conventional film-screen system can be replaced with both digital phosphor storage plate mammography and digital mammography, to be confirmed with further clinical trials.

Female↗
PubMed2002

[Scar or recurrence--comparison of MRI and color-coded ultrasound with echo signal amplifiers].

PURPOSE: MRI is the most reliable method to differentiate scar and recurrent carcinoma of the breast after surgical treatment. This study compares MRI and color-coded ultrasound with and without echo signal amplifier (ESA). MATERIALS AND METHODS: Forty-two patients with suspected recurrent tumors were enrolled in this prospective study, with 38 patients after breast conserving therapy and 4 after mastectomy. All patients had a clinical examination, mammography (n = 38), real time ultrasound (US), color-coded ultrasound without and with ESA (Levovist(R), Schering, Berlin), and dynamic MRI. The criteria used for duplex ultrasound were tumor vascularisation and flow pattern. The results were compared with histologic findings or the results of follow-up examinations for at least 12 months. RESULTS: The detection of penetrating or central vessels proved to be an accurate sign of malignancy in duplex ultrasound. With the application of ESA, additional vessels were detected within the lesions, increasing the diagnostic accuracy (83 % with ESA versus 79 % without ESA). The sensitivity of color-coded ultrasound improved from 64 % to 86 % with echo signal amplifier. The specificity was 86 % without and 82 % with echo signal amplifier. MRI was found to have a sensitivity of 100 % and a specificity of 82 %. The same 5 lesions were false positive on MRI and color-coded US after Levovist(R). No lesion without signs of vascularity within or in its vicinity was malignant. CONCLUSION: Color-coded ultrasound seems to be a promising method in the differentiation between scar and recurrence. Lesions with penetrating or central vessels have a high probability of being malignant, whereas lesions without any signs of vascularity inside or nearby have a high probability of being benign. Advantage of contrast-enhanced US is its ubiquitous availability.

Breast↗
PubMed2001

Detection of coronary artery stenoses by contrast-enhanced, retrospectively electrocardiographically-gated, multislice spiral computed tomography.

BACKGROUND: Multislice spiral computed tomography (MSCT) with retrospectively ECG-gated image reconstruction permits coronary artery visualization. We investigated the method's ability to identify high-grade coronary artery stenoses and occlusions. METHODS AND RESULTS: A total of 64 consecutive patients were studied by MSCT (4x1 mm cross-sections, 500-ms rotation, table feed 1.5 mm/rotation, intravenous contrast agent, retrospectively ECG-gated image reconstruction). All coronary arteries and side branches with a luminal diameter >/=2.0 mm were assessed concerning evaluability and the presence of high-grade stenoses (>70% diameter stenosis) or occlusions. Results were compared with quantitative coronary angiography. Of 256 coronary arteries (left main, left anterior descending, left circumflex and right coronary artery, including their respective side branches), 174 could be evaluated (68%). In 19 patients (30%), all arteries were evaluable. Artifacts caused by coronary motion were the most frequent reason for unevaluable arteries. Overall, 32 of 58 high-grade stenoses and occlusions were detected by MSCT (58%). In evaluable arteries, 32 of 35 lesions were detected, and the absence of stenosis was correctly identified in 117 of 139 arteries (sensitivity, 91%; specificity, 84%). If analysis was extended to all stenoses with >50% diameter reduction, sensitivity was 85% (40 of 47) and specificity was 76% (96 of 127). CONCLUSIONS: MSCT with retrospective ECG gating permits the detection of coronary artery stenoses with high accuracy if image quality is sufficient, but its clinical use may presently be limited due to degraded image quality in a substantial number of cases, mainly due to rapid coronary motion.

Aged↗
PubMed2001

[Mammography/stereotactically controlled vacuum excisional biopsy. Interventional methods in breast diagnosis].

As well as in the complementary mamma diagnosis (clinical examination, mammography, sonography) including the dynamic MRI and the mammography screening projects the interventional methods like mammographically/stereotactically guided vacuumbiopsy/excisional biopsy are established methods to avoid unnecessary open operations and they are integrated in the clinical routine. By using strict criterias it is a way to improve the specificity and the negative predictive value in the mamma diagnosis. In addition the interventional methods requires less costs, less time and reduces the morbidity in comparison to an open operation.

Biopsy↗
PubMed2001

MRI appearance of radiation-induced changes of normal cervical tissues.

Irradiation causes specific MRI changes in anatomic morphology and signal intensity. To avoid misinterpretation, it is important to consider the potential radiation changes of normal tissue in MRI. The aim of this study was to describe the detected radiation effects on normal cervical tissues in MRI. Pretreatment and posttreatment MRI of 52 patients with primary neck tumors were evaluated retrospectively. The MR imaging was performed before initiating radiotherapy and at the end of the treatment period. Patients underwent follow-up studies within 24 months after the end of irradiation. Edema was the main radiation-induced effect. It was detected in the epiglottis, larynx, pharynx wall, retro- and parapharyngeal space, salivary glands, muscles, and subcutaneous tissue. In some cases the bone marrow of the mandible showed edema, due to osteonecrosis. We additionally detected fluid accumulation in the mastoid cells. Radiation caused volume reduction of the parotid gland, thickening of the pharynx wall, and fatty degeneration of bone marrow. Magnetic resonance imaging is an excellent method of depicting radiation-induced changes of normal tissue. Especially T2-weighted sequences allow the detection of even slight edema. It is important to be aware of the most common radiation-induced changes in MRI and to take them into account when assessing an examination.

Adult↗