Search PubMed⌕ Search

Biomedical subjects

F Fischbach

Publications and source records attributed to F Fischbach.

At least 19 recordsLinked to original sources
PubMed2005

Magnetic resonance imaging of hyaline cartilage defects at 1.5T and 3.0T: comparison of medium T2-weighted fast spin echo, T1-weighted two-dimensional and three-dimensional gradient echo pulse sequences.

PURPOSE: To evaluate and compare the diagnostic accuracy of appropriate magnetic resonance (MR) sequences in the detection of cartilage lesions at 1.5T and 3.0T. MATERIAL AND METHODS: Twelve chondral defects of varying depths, widths, and locations were created in the retropatellar hyaline cartilage in six sheep cadaver limbs. Axial images employing three fat-suppressed imaging sequences--(1) a T2-weighted fast spin-echo (FSE) sequence, (2) a two-dimensional (2D) and (3) three-dimensional (3D) gradient-echo (GE) sequence at 1.5T and 3.0T using an extremity quadrature coil--were evaluated by three experienced radiologists. Statistical analysis of the results consisted of receiver operating characteristics (ROC) and significant testing using the bivariate chi-square test. In addition, signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were evaluated with significance testing using the Wilcoxon test. RESULTS: The 3D GE sequence compared favorably with other sequences at 3.0T and 1.5T (Az=0.88 at 3.0T and Az=0.85 at 1.5T) missing only one small grade 2 lesion. 2D GE imaging was inferior to 3D imaging at both field strengths (P<0.05) in general. However, compared to 1.5T, lesion detectability was improved at the higher magnetic field of 3.0T (Az=0.81 and 0.73 at 3.0T and 1.5T, respectively). FSE images showed significantly inferior sensitivity and less anatomical detail compared to the GE sequences at both field strengths (Az=0.64 and 0.72 at 3.0T and 1.5T, respectively; P<0.05). However, compared to 1.5T, lesion detectability SNR and CNR values were superior in all sequences tested at 3.0T. CONCLUSION: MRI at 3.0T improves SNR and CNR significantly in the most common sequences for cartilage MRI, resulting in an improvement in chondral lesion detection. GE imaging therefore allows resolution to be increased in an acceptable time manner for patient comfort, and the 3D GE fat-suppressed sequence at 3.0T appears to be best suited for cartilage imaging in a clinical setting.

Animals↗
PubMed2005

Effect of dose on image quality in a detector-based dual-exposure, dual-energy system for chest radiography.

PURPOSE: To assess the image quality of subtracted soft tissue and bone images of a CsI-detector-based dual-energy system for chest radiography at varying dose levels. MATERIAL AND METHODS: We evaluated a CsI-detector-based, dual-exposure, dual-energy prototype system; 126 patients were categorized into groups of small, medium, and large. Fixed values were applied for mAs and mA. The patients were randomized into two groups with intended higher and lower speed pairs of approximately 400/1000 (high and low energy shot) and 200/500, respectively. True speed equivalents were calculated retrospectively using the detector dose. Image quality was evaluated by two highly experienced radiologists in consensus applying a rating scale of 1 to 5 for quality indicators such as image noise, residual bone structures, motion artifacts, and others. RESULTS: Significantly decreased noise and a significant improvement for display of bone details in the bone image were noted with the higher dose, whereas a significant increase in motion artifacts reduced image quality at the higher dose. CONCLUSION: Radiation dose did not significantly influence the perception of dual-energy image quality. Dual-energy subtraction, as described, has the potential to become a future routine application in chest radiography.

Aged↗
PubMed2005

Colon dissection: a new three-dimensional reconstruction tool for computed tomography colonography.

PURPOSE: To improve the sensitivity of computed tomography (CT) colonography in the detection of polyps by comparing the 3D reconstruction tool "colon dissection" and endoluminal view (virtual colonoscopy) with axial 2D reconstructions. MATERIAL AND METHODS: Forty-eight patients (22 M, 26 F, mean age 57 +/- 21) were studied after intra-anal air insufflation in the supine and prone positions using a 16-slice helical CT (16 x 0.625 mm, pitch 1.7; detector rotation time 0.5 s; 160 mAs und 120 kV) and conventional colonoscopy. Two radiologists blinded to the results of the conventional colonoscopy analyzed the 3D reconstruction in virtual-endoscopy mode, in colon-dissection mode, and axial 2D slices. RESULTS: Conventional colonoscopy revealed a total of 35 polyps in 15 patients; 33 polyps were disclosed by CT methods. Sensitivity and specificity for detecting colon polyps were 94% and 94%, respectively, when using the "colon dissection", 89% and 94% when using "virtual endoscopy", and 62% and 100% when using axial 2D reconstruction. Sensitivity in relation to the diameter of colon polyps with "colon dissection", "virtual colonoscopy", and axial 2D-slices was: polyps with a diameter >5.0 mm, 100%, 100%, and 71%, respectively; polyps with a diameter of between 3 and 4.9 mm, 92%, 85%, and 46%; and polyps with a diameter < 3 mm, 89%, 78%, and 56%. The difference between "virtual endoscopy" and "colon dissection" in diagnosing polyps up to 4.9 mm in diameter was statistically significant. CONCLUSION: 3D reconstruction software "colon dissection" improves sensitivity of CT colonography compared with the endoluminal view.

Colon↗
PubMed2004

[(1)H magnetic resonance spectroscopy (MRS) of the liver and hepatic malignant tumors at 3.0 Tesla].

Use of whole-body MRI beyond 1.5 Tesla (T) has initiated a renaissance in spectroscopic procedures (MRS). The superior signal-to-noise ratio of clinical 3T tomographs allows reliable acquisition of MR spectra not only in fixed organs but also in targets moved by breathing such as the liver. The following contribution describes the principles of (1)H MRS and our own initial experiences with spectroscopy of the liver and hepatic malignant tumors with 3T whole-body MRI.

Humans↗
PubMed2004

[Comparison of different MRI sequences with and without application of Gd-BOPTA as follow-up after LITT].

PURPOSE: Comparison of various MR imaging techniques without and with the application of Gd-BOPTA for the follow-up of thermal tumor ablations by means of laser-induced therapy (LITT). MATERIALS AND METHODS: Thermal tumor ablations were performed with LITT in 19 patients showing a local recurrence. The metastases were from colorectal carcinoma in 15 cases (78.9 %) and from cervix, bronchial, gastric and renal carcinoma respectively in one patient each. The size of the metastases before ablation was on average 38.5 mm (min = 25 mm, max = 58 mm). The MRI protocol consisted of T2 UTSE FS, T1 w GRE without and with Gd-BOPTA at an early (20 s post injection) and late stage (> 120 min post injection). Two independent radiologists evaluated image contrast of the local relapse and necrosis in comparison to the surrounding healthy liver parenchyma on a scale from - 10 to + 10. Liver parenchyma was in any sequence 0. Recurrences were confirmed with follow-up examinations in all patients. Statistical analysis was performed by means of Wilcoxon and Kendall's W-test. RESULTS: Both radiologists found absolute ratios for contrast differences between thermal necrosis and local recurrence, with an average of 10.95 for T2 w UTSE FS and of 6.58 for T1 w GRE without, and of 4.05 for T1 w GRE with Gd-BOPTA in the early and of 2.26 in the late stage. Superiority for UTSE FS was significant (p < 0.05). The statistical analysis showed a high agreement for both radiologists for all values (p < 0.001). CONCLUSION: For early detection of local recurrences after thermal ablation T2 w UTSE FS is most suitable. For the detection of new foci, the use of liver specific contrast media is advisable.

Contrast Media↗
PubMed2004

[Value of various MR sequences using 1.5 and 3.0 Tesla in analyzing cartilaginous defects of the patella in an animal model].

PURPOSE: Comparison of MRI and macropathologic evaluation using various sequences and field strengths in the detection, localization and measurement of cartilage defects in an animal model. MATERIALS AND METHODS: After open creation of retropatellar cartilage defects of various widths, depths and locations in 8 cadaveric sheep knee joints, the knees were examined using a fat-suppressed (FS), proton density-weighted (PD) fast spin echo (FSE), and 2D and 3D gradient echo (GE) sequences on 1.5 T and 3.0 T MR scanners. The images were analyzed by two independent radiologists in a blinded manner, by dividing the patella into 15 virtual segments. The results were correlated with the macropathologic findings with regards to location, width, and depth of the defects. RESULTS: The highest sensitivity (67.1 %), diagnostic accuracy (85.4 %), positive (87.3 %), and negative (84.7 %) predictive values in detecting defects were obtained using the 3.0 T FS-3D-GE sequence. The highest specificity (95.6 %) yielded the 3.0 T FS-2D-GE sequence, with the other sequences inferior by no more than 2.6 %. In general, FS-3D-GE sequences were superior to FS-2D-GE (3.0 T: p < 0.05; 1.5 T: p < 0.05) and especially to FS-PD-FSE sequences (3.0 T: p < 0.01; 1.5 T: p < 0.05). In determining the defects' widths, the 3.0 T FS-3D-GE sequence was superior to all other sequences (correct measurements: 50.0 %), with only slight superiority to the 1.5 T FS-3D-GE sequence (46.9 %, p > 0.05) but clear superiority to the other sequences (28.1 - 40.6 %, vs. 1.5 T FS-PD-FSE: p < 0.05, vs. other sequences: p > 0.05). To determine the defects' depths, the 1.5 T FS-3D-GE sequence was most reliable (correct measurements: 53.1 %), followed by the 3.0 T FS-3D-GE sequence (50.0 %, significance of difference: p > 0.05). CONCLUSION: In detecting cartilage defects, the field strength of 3.0 Tesla was only superior to 1.5 T MRI using fat-saturated 3D- or 2D-GE-sequences but not in fat-saturated proton density-weighted SE-sequences. In determination of depth and length of the defects, the higher field strength was not advantageous.

Adult↗
PubMed2003

[CT-colonography with the 16-slice CT for the diagnostic evaluation of colorectal neoplasms and inflammatory colon diseases].

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.

Colonic Polyps↗
PubMed2003

Comparison of indirect CsI/a:Si and direct a:Se digital radiography. An assessment of contrast and detail visualization.

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.

Cesium↗
PubMed2000

[Actinomycosis of the pelvis with an indwelling IUD].

Infection with actinomycosis israeli (an anaerobic, gram-positive bacterium) presents as chronic inflammation with tendency to fibrosis and suppuration with formation of external sinuses. Cervicofacial, thoracic and abdominal forms of the disease made up 95% of cases of actinomycosis. A 53-year-old woman was admitted to the hospital because of a pelvic mass which was thought to be malignant. A laparotomy was performed and the histologic examination showed actinomycosis. The patient first received penicillin followed by tetracyclin and the pelvic mass shrunk. One year later no more mass was detectable. We think that the IUP in place over years is the source for this infection.

Actinomycosis↗
PubMed1999

Evaluation of IS1245-based PCR for detection of mycobacterium avium bacteraemia in AIDS patients.

A PCR method based on the repetitive IS1245 sequence was evaluated for the detection of Mycobacterium avium bacteraemia in AIDS patients. Two blood preparation methods were applied: lysis of erythrocytes using a hypotonic buffer and Ficoll density centrifugation. Results were compared with culture and PCR amplification of the non-repetitive pMav22 sequence. Fifty-one of 251 tested samples grew M. avium. Bacterial densities lower than 10 cfu/ml blood were frequent, they occurred in 59% of blood samples from patients with mycobacteraemia. Inhibitory substances were detected more frequently with the lysis method (36%) than the Ficoll processed samples (19%). While specificity of PCR was high, sensitivities varied according to the methods used and the load of infection in the bloodstream. False-negative PCR results were attributable to low level bacteraemia and inhibition of PCR. Moreover, 1 of 186 and 9 of 51 M. avium strains investigated lacked the IS1245 and the pMav22 sequence, respectively. Sensitivities of culture, IS1245- and pMav22-based PCR were 88, 64 and 58%, within the lysis processed samples and 95, 86 and 50% using Ficoll prepared samples, respectively. Thus, we conclude that IS1245-based PCR is a rapid and specific method for diagnosing M. avium bacteraemia and shows a higher sensitivity than single copy gene targets, but that the sensitivity is inferior to culture.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Ciprofloxacin/metronidazole vs. cefoxitin/doxycycline: comparison of two therapy schedules for treatment of acute pelvic infection].

The efficacy and safety of two antibiotic regimens for the treatment of acute pelvic inflammatory disease (PID) was compared in a prospective and randomised study. 57 patients received either 0.2 gms ciprofloxacin intravenously b.i.d. in combination with 0.5 g metronidazole intravenously t.i.d. (n = 26), or alternatively 2 g cefoxitin intravenously t.i.d. in combination with doxycycline 0.1 g b.i.d. (n = 31). After commencing therapy intravenously, medication with ciprofloxacin, metronidazole and doxycycline was continued orally after two or three days. In the ciprofloxacin/metronidazole group, PID was found to be severe in 7, moderate in 12 and mild in 7 patients. The numbers in the cefoxitin/doxycycline group were 8, 20 and 3 respectively. The clinical result after treatment with ciprofloxacin/metronidazole was resolution of all symptoms in 24 patients and improvement in 2 others. In the cefoxitin/doxycycline treated group, resolution was found in 27 patients, improvement in 2 others. Failure occurred in 2 patients. 53 different microorganisms as the suspected cause of PID were isolated in the ciprofloxacin/metronidazole group and 56 in the cefoxitin/doxycycline group. According to our clinical and bacteriological criteria, treatment for PID was successful in 97% of the ciprofloxacin/metronidazole group and in 87% of the cefoxitin/doxycycline group. Adverse reactions were found in 4 patients in the ciprofloxacin/metronidazole treated group. Therapy had to be terminated in 3 of these patients. In the cefoxitin/doxycycline group 2 patients had adverse reactions, and therapy had to be terminated in one of these patients. According to our results, both antibiotic regimens can be recommended for the treatment of PID.

Adult↗
PubMed1994

[The personal computer as a rehabilitation aid for severely handicapped patients].

The case example presented outlines the efforts of a quadriplegic young man who has succeeded in finding himself an occupational basis through training as an expert in electronic desktop publishing (DTP). Due to his severe mobility handicaps, computerized workstations for DTP training had been put up both in the training company and in his own home. These Desktop Publishing systems enable even very severely disabled persons to perform at a par with non-disabled persons. If this adapted workplace is connected to a communication network, the work results need not be delivered materially to the place where they are needed or further worked on, but can be dispatched electronically to the addressee. Communication networks enable the disabled person to easily exchange data with other workstations, or, through the use of modems to access the public telephone system, to send messages from his private environment (e.g., for sending fax messages or placing information in his partners' electronic mailboxes).

Adult↗
PubMed1993

[Importance of plasma PMN granulocyte elastase concentration determination in pregnant patients with premature rupture of fetal membranes].

The aetiology of preterm rupture of membranes is not yet completely understood. Local infections of the vagina and cervix have attracted special attention during the last years. Ascending infection with subsequent chorioamnionitis is a common complication of preterm rupture of membranes. Recognition of the beginning of a chorioamnionitis is usually based on clinical symptoms and laboratory findings like white blood cell count and C-reactive protein. The purpose of this study was to find out the diagnostic value of elastase, a protease of polymorphonuclear granulocytes, which is known to be involved in inflammatory processes. Fifteen out of thirty-three patients with preterm rupture of membranes developed a chorioamnionitis. Elastase plasma concentration levels > or = 32 ng/ml one day before delivery showed a significant correlation (p = 0.02) to the development of a chorioamnionitis. At this time neither white blood cell count, nor rectal body temperature showed significant correlations. Low elastase levels do not exclude an infection, whereas high levels indicate an infectious process. We conclude that elastase is a relevant marker of chorioamnionitis.

Adult↗
PubMed1993

Efficacy of clindamycin vaginal cream versus oral metronidazole in the treatment of bacterial vaginosis.

OBJECTIVE: To compare the efficacy and tolerance with 2% clindamycin vaginal cream versus oral metronidazole for the treatment of bacterial vaginosis. METHODS: This was a multicenter, randomized, double-blind study in which patients were randomly assigned to one of the following two regimens in a 1:1 ratio: clindamycin phosphate vaginal cream 2% (5 g intravaginally at bedtime for 7 days) plus two placebo capsules (twice a day for 7 days) or metronidazole 500 mg (two 250-mg capsules orally twice a day for 7 days) plus placebo vaginal cream (5 g intravaginally at bedtime for 7 days). The patients were seen for follow-up at 5-10 days and 25-39 days after completion of therapy. RESULTS: Seven investigators, four in Germany, two in Austria, and one in Switzerland, enrolled 407 patients. Four patients never received either protocol drug, leaving 403 evaluable for safety. Two hundred thirty-four patients were evaluable for efficacy. The analysis for all evaluable patients showed no significant difference between treatment groups. The cure or improvement rate at 1 month after therapy was 83% in the clindamycin group versus 78% in the metronidazole group. The incidence of drug-related adverse medical events was approximately 12% in both groups. CONCLUSIONS: Oral metronidazole and intravaginal clindamycin cream had a similar efficacy of 78 to 83%. Both drugs were tolerated, with vaginal candidiasis developing in 8.5 and 4.7% of the patients in the clindamycin and metronidazole groups, respectively.

Administration, Intravaginal↗
PubMed1989

[Producing technical drawings using the feet--a special work site for a thalidomide-damaged technical draftswoman].

Persons with upper limb deficiency do not find it easy to lead a somewhat "normal" private, occupational and social life. True, society offers many kinds of assistance and support; it nevertheless is very much a matter of how the individual concerned reacts to the positive and negative influences and imponderabilities encountered. The present report sets out the efforts of a thalidomide-affected young woman who, in the face of numerous obstacles, left nothing untried to create a life basis of her own by obtaining a good vocational qualification as a technical draftswoman, regardless of her congenital upper limb amputation. Her success is proof enough that she chose the right course. This example, in more general terms, should perhaps be considered a prompting for society, on the one hand, to undertake the endeavour of providing quality assistance even in extreme situations and, on the other, to be prepared to have confidence even in those with very severe physical disablement to be able to accomplish goals which at the first glance may appear "nonsensical", such as a desire to be trained as a technical draftswoman even though one's hands are missing. The account not least shows the positive impact help and self-help may have in the rehabilitation of very severely disabled persons. The disabled person's reward primarily lies in the sense of independence achieved and in financial self-reliance, which in turn generate a sense of feeling free inwardly and outwardly.

Adult↗