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Biomedical subjects

R W Günther

Publications and source records attributed to R W Günther.

At least 19 recordsLinked to original sources
PubMed1995

Gadopentetate-dimeglumine-enhanced MR imaging of osteonecrosis and osteochondritis dissecans of the elbow: initial experience.

Magnetic resonance imaging (MRI) was performed on seven patients with aseptic osteonecrosis (n = 4) and osteochondritis dissecans (OCD; n = 3) of the elbow. Precontrast MRI was superior to plain radiographs, which did not show any abnormality in three cases of osteonecrosis. On gadopentetate-dimeglumine-enhanced T1-weighted images, which were obtained in three patients with osteonecrosis and three patients with OCD, all cases of osteonecrosis demonstrated homogeneous enhancement of the lesions. All cases of OCD were diagnosed on plain radiographs. On MRI one showed significant enhancement of the loose body. In another case an incompletely enhancing loose body was surrounded by a diffusely enhancing region. In the third patient only a small marginal enhancement of the defect was observed. Our results suggest that MRI can improve the accuracy in diagnosis of aseptic osteonecrosis of the elbow. The use of gadopentetate dimeglumine allows the viability of the lesions or the loose bodies to be demonstrated and reparative tissue to be detected.

Adolescent↗
PubMed1995

[Functionally determined area changes in the oro-pharyngo-laryngeal vocal tract of singers as shown by magnetic resonance tomography].

The oro-pharyngeal-laryngeal resonating spaces were studied in 12 singers at varying stages of their training by means of medio-sagittal MRI images, and the results were compared. The singers were requested to sing /a/ /u/ and /i/ at various pitches and with increasing loudness. The total oro-pharyngo-laryngeal areas were integrated by means of the MRI sections. The relationship between the oro-pharyngeal and pharyngo-laryngeal areas was determined, as well as their ratio to total area. With increasing volume there was increase in the area of the oro-pharyngeal component with no change in the pharyngo-laryngeal component. The relationship of the partial areas depends on the extent of training of the singer.

Adult↗
PubMed1995

[The percutaneous CT-guided treatment of osteoid osteomas: a combined procedure with a biopsy drill and subsequent ethanol injection].

PURPOSE: The purpose of this study was the clinical evaluation of a percutaneous treatment modality in patients with an osteoidosteoma. PATIENTS AND METHODS: 6 patients with an osteoidosteoma of the upper (n = 1) and lower (n = 5) extremity which were confirmed on plain film radiographs and computed tomography underwent CT controlled drill biopsy of the nidus with subsequent injection of 96% ethanol into the biopsy channel to sclerose probably remaining remnants of the nidus. The procedure was started under local anaesthesia, but drilling of the nidus was carried out under a short general anaesthesia using ketamine. RESULTS: The intervention was successful in all patients. No postinterventional infection occurred and no recurrence was observed in any of the patients in a follow-up time between 0.5 and 2 years. CONCLUSION: Although only 6 patients were treated until now, we conclude that this combined procedure using a bone biopsy system and the subsequent injection of alcohol is a safe and successful procedure for percutaneous treatment of osteoidosteoma.

Adolescent↗
PubMed1995

[Percutaneous treatment possibilities in thrombotic occlusion of Brescia-Cimino dialysis shunts].

PURPOSE: Acute thrombotic occlusion of Brescia-Cimino forearm fistulae is a severe complication. Aspects of percutaneous therapy include balloon dilatation, thrombolysis and mechanical thrombectomy. We report on 21 cases with obstructed shunts. Clinical evaluation and palpation helped to select each shunt for an individual therapeutic approach. PATIENTS AND METHODS: One patient presented with a proximal arterial occlusion, three patients with a small occluding thrombus, 4 patients with a severe stenosis but only a small amount of thrombus and 13 patients with an extended amount of clot material. RESULTS: 7 patients underwent balloon dilatation alone, three patients thrombolysis with rtPA and 11 patients hydrodynamic thrombectomy. Arterialized shunt flow was reestablished in 20 of 21 cases. The shunt was reused for dialysis in 17 cases. Reobstruction within two weeks after intervention occurred in two cases. CONCLUSIONS: With regard to the individual clot size, different percutaneous methods are available for successful shunt recanalisation.

Acute Disease↗
PubMed1995

[Color-coded duplex ultrasonography in the diagnosis of renal artery stenosis].

PURPOSE: Colour-coded duplex sonography was performed for diagnosis of renal artery stenosis to define standards and criteria for stenosis. MATERIAL AND METHODS: In 20 normotensive volunteers and 123 patients with arterial hypertension, bilateral intrarenal Doppler spectra were examined and the following parameters including side ratios were calculated: pulsatility index (PI), resistance index (RI), acceleration time index (AT) and acceleration index (AI). RESULTS: In 29 of the 123 patients, angiography showed unilateral renal artery stenosis. Acceleration index (AI) was found as the most reliable parameter with a sensitivity of 100% and a specificity of about 94% for stenoses grading at least 70%. CONCLUSIONS: Colour-coded duplex sonography can depict relevant stenoses reliably, but anatomical variations may limit its value as a single screening method. Colour-coded duplex sonography can be, therefore, recommended as an adjunct to angiography for assessment of haemodynamic relevance.

Adolescent↗
PubMed1995

[The computed tomographic morphology of Crohn's disease and ulcerative colitis].

PURPOSE: To assess the value of computed tomography for the diagnosis of Crohn's disease and ulcerative colitis. METHOD: We analysed the CT examinations of 109 patients with 197 involved bowel locations. 81 patients suffered from Crohn's disease, 28 from ulcerative colitis. Diagnosis was based on the combination of clinical, endoscopic and histopathologic findings. Three radiologists evaluated the CT series concerning the presence of morphologic changes analogous to conventional radiographic findings. RESULTS: In Crohn's disease, we found irregular outer contours in 26% of cases. The bowel wall was thickened in 82%. In acute phases, the bowel wall was thickened in 100%. Abscess and fistula as complications of inflammatory disease were present in 26 and 14% respectively. In ulcerative colitis, a target sign of the bowel wall was present in 40%, whereas in Crohn's disease a homogeneous wall density was present in all but two cases. Reduced attenuation due to submucosal fat deposits was found in 16% and mucosal tunneling in 27% of cases with ulcerative colitis. Even if severe mucosal destructions were found, the outer contour of the gut was smooth and regular in 95% of the ulcerative colitis cases. CONCLUSION: CT can provide additional information on acuity, extent and complications in inflammatory bowel disease. In combination with conventional radiographic findings a three-step classification for Crohn's disease and ulcerative colitis (early changes, acute and chronic phase) can be proposed.

Adolescent↗
PubMed1995

[Intrarenal duplex sonography in detecting flow changes after renal PTA].

PURPOSE: Changes of the intrarenal Doppler signal were analysed before and after renal balloon dilatation to assess the technical success of PTRA. MATERIALS AND METHOD: In 33 patients, intrarenal Doppler signal was depicted before and after renal PTA. Doppler flow curve was analysed by using the acceleration index (AI), acceleration time index (AT) and resistance index (RI); for all indices side ratios (AI-R, AT-R and RI-R) were calculated. Balloon dilatation was angiographically successful in all cases. Average stenosis graded 71% before and 21% after PTA. RESULTS: By definition of limits for all indices used, a single patient was graded as non-stenotic before balloon dilatation by application of AI/AI-R and no patient was graded nonstenotic by AI/RI-R. After renal PTA, all indices significantly changed towards normal findings and by application of both AI/AI-R and AI/RI-R, only a single patient was graded stenotic after PTA. CONCLUSION: Intrarenal Doppler signal analysis reliably allows to detect flow changes following renal PTA in patients with renal artery stenosis. It may therefore be used as a noninvasive method to monitor flow improvement after renal PTA and during follow-up.

Adolescent↗
PubMed1995

[The rheolytic thrombectomy of an iliac vein].

As an alternative to thrombolysis, a patient with recent rethrombosis of the right iliac vein was successfully recanalized by using a 5 F rheolytic catheter system. The patient had undergone bilateral stent recanalisation of the pelvic veins after iliocaval thrombosis due to retroperitoneal fibrosis three months earlier.

Aged↗
PubMed1995

[The potentials of digital image-intensifier radiography exemplified by digital spot imaging (DSI)].

PURPOSE: We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. MATERIAL AND METHODS: Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. RESULTS: The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. CONCLUSION: The DSI system was well integrated in the daily routine of gastrointestinal examinations. Low dose imaging, direct availability of images and dynamic studies with a frame rate up to 8 images per second are the advantages of the DSI. The lower spatial resolution in some cases is a diagnostic disadvantage that can reduce the diagnostic information.

Contrast Media↗
PubMed1995

[The MR tomography of avascular necrosis of bone: the primary findings and the follow-up observations after core decompression].

PURPOSE: To assess the signal changes of avascular bone necrosis after core decompression. PATIENTS AND METHODS: 17 patients with avascular epiphyseal necrosis were examined by MRI using T1-weighted spin echo sequences before and after gadopentetate dimeglumine application, T2-weighted spin echo sequences and in some patients with fat-saturated 2D gradient echo sequences up to 22 months after core decompression. RESULTS: All patients but one recovered from symptoms after core decompression. Although the signal morphology of the necrotic area remained unchanged in the majority of the cases, a decrease of the joint effusion was observed as well as an ongoing signal increase after gadopentetate dimeglumine application. The last examinations displayed similar signal characteristics as on the preoperative scans; however, a reduction of the necrotic zone became evident. CONCLUSIONS: The decrease of joint effusion indicates successful core decompression, while a persistent signal increase after gadopentetate dimeglumine application reflects the viability of the necrotic area as well as an ongoing healing process.

Adult↗
PubMed1995

[The diagnosis of acute pulmonary embolism: a comparison between spiral CT and DSA in an animal experiment].

PURPOSE: The value of helical computed tomography (CT) for diagnosis of acute pulmonary embolism was assessed and compared with digital subtraction angiography (DSA) as a reference method. MATERIAL AND METHODS: In 11 dogs, lobar, segmental, and subsegmental occlusions of the pulmonary arteries were produced. Subsequent to selective pulmonary angiography, the animals were examined with contrast-enhanced helical CT. RESULTS: In the main and lobar pulmonary arteries there was a complete correlation between CT and DSA in documentation of total and partial embolic occlusions. Identification of segmental and subsegmental pulmonary emboli by CT required a second run with optimized parameters in 7 of 11 cases. Nevertheless, 18% of the peripheral arteries could not be classified. CONCLUSION: Helical CT as less invasive modality is competitive with DSA in demonstration of central pulmonary emboli. However, CT imaging of peripheral pulmonary emboli requires optimal bolus timing.

Acute Disease↗
PubMed1995

[The MRT of osteophytosis in experimental gonarthrosis].

PURPOSE: The value of MRI for the detection of knee osteophytosis was determined in an animal osteoarthritis model. METHODS: 10 dogs with experimentally induced unilateral osteoarthritis of the knee were investigated with MRI including 2-D-spin echo (SE) and 3-D-gradient echo (GE) imaging. The results were correlated with gross and histopathologic findings and with radiography. RESULTS: Osteophyte formation appeared early in the osteoarthritic process. Pathological analysis yielded 65 osteophytes. With 3-D-GE imaging, 91% of the osteophytes were detected, while 68% were visible on 2-D-SE images. With two-level radiography, 43% of the osteophytes were diagnosed. Additional use of tunnel view and conventional tomography increased the detection rate to 65%. Independent of the imaging technique, MRI revealed three different signal patterns of the osteophyte bone structure. Compared with the histologically evident fat marrow content and the grade of bone sclerosis, best agreement was achieved with 2-D-SE sequences. However, a discrepancy remained in 22%. A fibrocartilaginous layer at the osteophyte surface could be delineated especially on 3-D-GE images. CONCLUSIONS: MRI provides the highest standard in non-invasive diagnosis of osteophytes in the knee. 3-D-GE imaging in particular can demonstrate early and small osteophyte formation.

Animals↗