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Biomedical subjects

M Spahn

Publications and source records attributed to M Spahn.

14 recordsLinked to original sources
PubMed2005

Bladder carcinoma during pregnancy.

INTRODUCTION: We report 3 cases of bladder cancer during pregnancy and give a review of the literature in an attempt to evaluate tumor at presentation, characteristics, maternal and fetal outcome. MATERIALS AND METHODS: The case history of 3 pregnant women treated for bladder cancer in 2001 together with the results of a MEDLINE search from 1966 to 2003. RESULTS: Out of 27 cases of nonbilharzial bladder carcinoma, 74% presented with transitional cell carcinoma. Five patients had muscle-invasive tumors. Major symptom was hematuria in 81%, which was initially mistaken as vaginal bleeding in 22%. Only half of the tumors were identified by ultrasonography. Although superficial bladder carcinoma was transurethrally resected alone, outcome and prognosis are good. But the prognosis of locally advanced bladder carcinoma is poor. None of the fetuses delivered before 30 weeks of gestation survived. Two of the 5 patients died from the disease and follow-up is only short in the rest. CONCLUSION: Any doubtful genital bleeding during pregnancy without definite proof of vaginal/cervical origin should be investigated by both ultrasonography of the upper urinary tract and urethrocystoscopy. Superficial bladder tumors can be most effectively treated by transurethral resection followed by cystoscopy, whereas the prognosis of muscle-invasive bladder carcinoma is poor and demands more radical treatment, depending on the stage of pregnancy.

Adult↗
PubMed2003

[Flat-panel detectors in X-ray systems].

For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography,mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method. For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction potentials. These improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex image processing algorithms have the potential to enlarge the present diagnostic range of applications. Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic angiography. Characteristics of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution, the large dynamic range, the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods.

Angiography↗
PubMed2003

[Postoperative evaluation in uroradiology. Part 1: Nephrolithiasis, renal tumors and diseases ot the ureter].

Therapeutic strategies and operative techniques in urology develop rapidly. In particular, surgery becomes more and more differentiated and complex. Radiologists, especially uroradiologists wil have to provide special knowledge about urologic therapy and operative techniques in order to critically look at postoperative changes. Part I of this review will cover therapy and postoperative evaluation in nephrolitiasis, renal tumors and disease of the ureter. Using the appropriate modality at the appropriate time in postoperative course is discussed. Typical postoperative changes are shown. There is a focus on evaluation and typical radiologic findings in postoperative complications.

Humans↗
PubMed2003

[Postoperative radiologic evaluation in uroradiology. Part 2: Bladder, prostate, and testis].

Radiologists, especially uroradiologists, must retain abreast of rapid developments in urologic therapy and operative techniques in order to critically assess postoperative changes. Part 2 of this review will cover therapy and postoperative evaluation in bladder surgery, surgery in prostate cancer, and retroperitoneal disease associated with testicular tumors. Using the appropriate modality at the appropriate time during the postoperative course is discussed. A variety of alternatives are available to perform urinary diversion after radical cystectomy. Knowledge of operative techniques and postoperative anatomy are mandatory for interpretation of postoperative radiologic findings.

Adult↗
PubMed2003

[Penile fractures: controversy of surgical vs. conservative treatment].

This paper reviews the current status of information on diagnostic and therapeutic management of penile fractures, focusing on the controversy between surgical vs. conservative treatment of this uncommon injury. Penile fracture, commonly defined as a rupture of the tunica albuginea and corpus cavernosum, is a serious urological disorder demanding surgical management. The diagnostic procedure classically consists of history taking, physical examination and urinary status. Determination of the extent of severity and location of the rupture in the tunica albuginea takes foremost priority and requires additional imaging procedures, such as ultrasound or cavernosography, which will impart enough diagnostic information for the correct choice of treatment. In some cases, the urethra is injured as well. Immediate surgical repair offers complete recovery for patients with penile fracture in most cases, even in the presence of urethral injury. Although penile fracture is easily recognized and can therefore be classified as a "first-look diagnosis", therapy remains controversial to date. The correct therapeutical approach is a vital factor in management, as the associated significant morbidity can result in complete loss of erectile function, painful erections or penis deviation. Early surgical treatment is strongly recommended because of the excellent results, shorter hospitalization, less morbidity and an early return to sexual activity.

Anti-Bacterial Agents↗
PubMed2001

[Fibromyxoid pseudosarcoma of the urinary bladder. Case report and review of the literature of a rare disease].

Pseudosarcomatous fibromyxoidtumors (PSF) of the bladder are rare, benign tumors consisting of myofibroblastoid bladder wall proliferations of unknown etiology. Misinterpretation as a sarcoma is common and due to infiltrative growth and cellular pleomorphism and may leaed to false radical treatment. We present a 27 year old man with PSF presenting with microhematuria. Results of clinical, radiological and histopathological examinations and therapy are presented. A. review of the literature data of the to our knowledge 73 cases that have been reported in the literature is given.

Adult↗
PubMed2001

Color Duplex sonography vs. computed tomography: accuracy in the preoperative evaluation of renal cell carcinoma.

PURPOSE: Accurate imaging is essential for correct operative planning and successful surgical intervention in renal cell carcinoma (RCC). Our objective was the comparison of color duplex sonography with spiral computed tomography (CT) and surgical-pathological findings in the evaluation of renal masses to determine tumor localization, size, tumor thrombus extent and lymph node metastases. METHODS: We evaluated 60 patients with a renal mass in a prospective study. Both color duplex sonography and CT were performed by different investigators without knowledge of the supposed diagnosis. The color Doppler findings were compared to CT and surgical pathological findings. RESULTS: The sensitivity of color duplex sonography in the detection of RCC and lymph node metastases is comparable to that of CT (100%). Color duplex sonography was superior in the detection of renal vein involvement. Color duplex sonography alone allowed correct planning of the surgical procedure without intraoperative changes in all patients. CONCLUSION: Duplex sonography provides exactly the same information as CT. Although duplex sonography is less expensive with lower exposure to radiation, most surgeons will still probably demand CT for diagnosis, especially as this method is unerring and duplex sonography highly depends on the expertise of the person using it.

Aged↗
PubMed2000

Digital radiography with a large-area, amorphous-silicon, flat-panel X-ray detector system.

RATIONALE AND OBJECTIVES: To investigate the image quality of a digital radiography system with an amorphous-silicon, large-area, digital flat-panel detector. METHODS: A flat-panel detector based on a matrix of amorphous silicon was integrated into a projection radiography system. The scintillator consisted of a layer of structured cesium iodide. The active matrix size of 30002 pixels together with a pixel size of 143 microm provided a large image area of 43 x 43 cm2. Basic image quality parameters such as detective quantum efficiency (DQE) and modulation transfer function (MTF) were measured and compared with those obtained with conventional systems. RESULTS: The measurement of DQE yielded a high value of 70% at zero spatial frequency. At a system dose equivalent to 400 speed, the DQE of the digital system was a factor of two larger than the DQE of a storage phosphor or screen-film system within the entire spatial frequency range between zero and the Nyquist limit of 3.5 line pairs per millimeter. The flat-panel detector furthermore has an MTF that is superior to that in regular screen-film systems and also provides a substantially larger dynamic range. CONCLUSIONS: This new technology demonstrates its potential to provide equal or superior image quality to conventional screen-film systems and to reduce patient exposure to radiation dose. The advantages of digital radiography systems, based on a flat-panel detector as an instant image display, facilitation of work flow in the radiology department, and digital networking and archiving, are well in sight.

Humans↗
PubMed2000

[Diagnosis and therapeutic options for prolonged erection and priapism: up-date review].

OBJECTIVE: To review the pathophysiology, diagnostic methods and treatments of priapism, with special reference to alternative treatment options. METHODS: The different surgical options are presented and discussed, with special emphasis on the oral drugs and intracavernous therapy for priapism. The advantages and inconveniences of the different agents and surgical techniques are discussed. The publications in MEDLINE 1980-2000, our experience and the results of our studies previously reported in the literature were reviewed. RESULTS/CONCLUSIONS: Complete detumescence and recovery of normal arterial blood flow can be achieved in a majority of the cases by systematic and standardized management. Sedatives, alpha-adrenergic agents or oral ketamine hydrochlorate can be utilized. However, due to the importance of the time factor, intracavernosal therapy should be the priority for persistent erection, using alpha-adrenergic agonists or other alternatives, such as methylene blue, which do not have the well-recognized risks of the conventional agents. The etiology of the priapism should be clearly established by metabolic and hemodynamic studies, since treatment will be based on the underlying disorder. In veno-occlusive low flow priapism, surgical shunting should be performed if aspiration of intracavernosal blood and other treatments are not successful. Arterial embolization and surgical ligation should be performed for high flow persistent priapism.

Humans↗
PubMed1999

Self-normalizing method to measure the detective quantum efficiency of a wide range of x-ray detectors.

The detective quantum efficiency (DQE) is widely accepted as the most relevant parameter to characterize the image quality of medical x-ray systems. In this article we describe a solid method to measure the DQE. The strength of the method lies in the fact that it is self-normalizing so measurements at very low spatial frequencies are not needed. Furthermore, it works on any system with a response function which is linear in the small-signal approximation. We decompose the DQE into several easily accessible quantities and discuss in detail how they can be measured. At the end we lead the interested reader through an example. Noise equivalent quanta and normalized contrast values are tabulated for standard radiation qualities.

Models, Theoretical↗
PubMed1998

[Vascular surgery, implant surgery and vacuum erectile aids. Review-overview-prospects of 3 therapy options in erectile dysfunction].

Vascular surgery or penile prosthesis implantation are the main surgical options for erectile dysfunction. In this category, penile revascularization is the only causal therapy for selected patients: males younger than 50 years of age at time of surgery, maximum of two risk factors, exclusion of diabetes mellitus. Long-term success decreased to 53% to 55% in comparison to first encouraging reports of 80% success. Venous surgery resulted in an even more distinct decline of success the longer the elapse of time after surgery. Long-term success dropped under 40%, leaving only a few indications for penile venous ligation. In contrast, penile prosthesis implantation results in high satisfaction rates. Despite this, it is not generally recommended as first choice surgical management as it is linked to irreversible damage of the cavernosal bodies. Among numerous types of penile implants, preference is nowadays mostly given to the three-piece hydraulic models. However, such complications as defective or perforated cylinders in up to 35% after 5 years have arisen, depending on the type of implant. In a selected patient group, vacuum constriction devices with a mean patient acceptance of 75% (50% to 90%) seldom result in complications and are thus considered to be a well-established therapeutical option.

Arteriovenous Shunt, Surgical↗
PubMed1998

Amorphous silicon, flat-panel, x-ray detector versus screen-film radiography: effect of dose reduction on the detectability of cortical bone defects and fractures.

RATIONALE AND OBJECTIVES: The purpose of this phantom study was to assess the diagnostic performance of a self-scanning, solid-state amorphous silicon (a-Si) detector in skeletal radiography using different exposure parameters. METHODS: A flat-panel detector (15 cm x 15 cm), based on a-Si technology with 143 microm x 143 microm pixel size, 1k x 1k matrix, and 12 bit digital output was used. State-of-the-art screen-film radiography (SFR; speed 400, detector dose 2.5 microGy) was compared with a-Si images taken at doses that were equivalent to a speed of 400, 800, 1,250, and 1,600, respectively. A total of 232 segments of long tubular deer-bones (femur, tibia, humerus, radius) had 110 artificial fractures and 112 cortical defects simulating osteolytic lesions. Receiver operating characteristic analysis was performed for 9,280 observations made by four independent observers. Two-tailed Student's paired t test was used for statistical analysis (95% confidence level). RESULTS: Receiver operating characteristic analysis yielded equivalent results of the a-Si and SFR system. Even at the lowest dose there were no statistically significant differences between both imaging modalities with respect to the detectability of fractures and cortical defects. CONCLUSIONS: The results of this study indicate that a-Si detector technology holds promise in terms of dose reduction in skeletal radiography without loss of diagnostic accuracy.

Animals↗
PubMed1997

Flat-panel x-ray detector using amorphous silicon technology. Reduced radiation dose for the detection of foreign bodies.

RATIONALE AND OBJECTIVES: The authors evaluate a new flat-panel x-ray detector (FD) with respect to foreign body detection and reduction of radiation dose compared with screen-film radiography. METHODS: Flat-panel x-ray detector is based on amorphous silicon technology and uses a 1 k x 1 k photo-detector matrix with a pixel size of 143 x 143 microns and 12-bit digital output. A thallium-dotted cesium iodide scintillation layer converts x-rays into light. An ex vivo experimental model was used to determine the detectability of foreign bodies. Foreign bodies with varying sizes were examined: glass with and without addition of lead, bone, aluminium, iron, copper, gravel fragments, and graphite. Four hundred observation fields were examined using conventional radiography (speed, 400; system dose: 2.5 microGy) as well as FD with a simulated speed of 400, 800, 1200, and 1600, corresponding to a detector dose of 2.5 microGy, 1.25 microGy, 0.87 microGy, and 0.625 microGy, respectively. Four independent radiologists performed receiver operating characteristic analysis of 8000 observations. RESULTS: Flat-panel x-ray detector with a simulated speed of 400 was significantly superior (P = 0.012) to screen-film radiography (speed, 400). At a simulated speed of 800 and 1200 FD yielded results equivalent to screen-film radiography. Flat-panel x-ray detector was significantly inferior to screen-film radiography at a simulated speed of 1600 (P = 0.012). CONCLUSIONS: Flat-panel x-ray detector technology allows significant reduction in radiation dose compared with screen-film radiography without loss of diagnostic accuracy.

Foreign Bodies↗