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Biomedical subjects

U Mödder

Publications and source records attributed to U Mödder.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Possibilities of the use of MR tomography-based cerebral blood volume maps in the diagnosis of brain tumors].

PURPOSE: Today contrast enhanced MR imaging is a reliable method for detecting mostly distinguishing between different histological types of tumours. In this study we use a MR-based method to measure the regional cerebral blood volume (rCBV). Using this technique we try to judge the grading and vitality of the tumours. METHODS: 26 patients with various types of brain tumours were examined. To calculate rCBV-maps of one slice, low-dosed Gd-DTPA was injected as a bolus. Using the relaxation effect the obtained signal intensity-time curves were converted pixel-wise into rCBV images. For the tumours rCBV-ratios were calculated relative to the corresponding area in the contralateral hemisphere. RESULTS: In the investigated group all tumours were detected on the basis of a raised rCBV-ratio. Since only vital parts of the tumour are perfused, the rCBV maps may be used to determine the place of biopsy. CONCLUSIONS: The differential diagnosis of all histological tumour types was not possible on the basis of rCBV values. Distinction between low grade and high grade gliomas was also not significant. However, a low grade glioma can be excluded if the morphological images definitely indicate an astrocytoma and if the rCBV-ratio was higher than 2.

Adult↗
PubMed1995

[Intraarterial digital subtraction angiography (i.a. DSA) of the lower limb using fine needle technique].

PURPOSE: Severe peripheral arterial occlusive disease (pAOD) requires adequate diagnostic imagery of poststenotic and postocclusive vascular regions. This study was designed to evaluate the validity of i.a. DSA using fine-needle technique (FNA) especially concerning the vascular area of the lower limb. MATERIAL AND METHODS: 206 FNA of the lower limb wer evaluated retrospectively. Besides evaluation of the image quality of the 1119 angiographic image series, main points of interest were the determination of accuracy of the FNA in comparison to the operative findings, the average radiocontrast agent consumption and the rate of complication. RESULTS: In all cases the image quality was rated either very good or good in the pelvic, femoral and popliteal vessels. 94% of the image series of the lower leg and foot could be rated as well as very good/good although 75% of all patients demonstrated an advanced stage of pAOD. Accuracy of FNA compared to operative findings came up to 82%. The average radiocontrast consumption amounted to 69 ml per examination. Overall, two major complications were seen. CONCLUSION: I.a. DSA of the lower limb using fine-needle-technique is an easily applied angiographic method of low radiocontrast agent consumption and a low complication rate. Essential information can be acquired preoperatively in planning far peripheral bypass anastomoses. Postoperative vascular complications can be safely assessed.

Angiography, Digital Subtraction↗
PubMed1994

[The spectrum of the findings of arterial digital subtraction angiography in patients following kidney transplantation].

Digital subtraction angiography (DSA) was performed in 53 of 417 patients with renal transplants. The incidence of clinical apparent vascular complications was 9.1% of all patients with renal transplants (38/417). The most frequent vascular disorders were formed by arterial stenoses at 5.0% of the cases followed by arterial obstructions in 1.7% of the patients. Rare vascular complications were arteriovenous fistulas (0.7%), aneurysms (0.5%) and venous thromboses (0.2%). Because of the high diagnostic value of intraarterial DSA, all patients with renal transplants with a complicated postoperative course should be eligible for angiographic control. In case of a suspected vascular disorder intraarterial DSA should be performed at an early stage.

Adult↗
PubMed1994

[The computed tomographic diagnosis of inflammatory abdominal aortic aneurysms].

Amongst 1599 patients undergoing surgery for abdominal aortic aneurysm, there were 89 patients (5.6%) who showed typical features of inflammatory aneurysms of the abdominal aorta (IAAA). 37 of the 89 patients had been examined preoperatively by CT. In 73% of the cases (27/37) a correct diagnosis had been made. Localisation, width and extent of the IAAA was correctly diagnosed in all patients. Involvement of the renal arteries by the inflammatory process, the extent of thrombus and of mural calcification were accurately shown. The inflammatory tissues were typically ventral and lateral to the aorta. Frequently, there were adhesions to neighbouring structures. Aortic rupture, aortic dissection and retroperitoneal lymphoma may produce similar CT appearances; nevertheless, CT remains at present the method of choice for the diagnosis of IAAA because of its high sensitivity.

Adult↗
PubMed1994

Possible transmission of sarcoidosis via allogeneic bone marrow transplantation.

Allogeneic bone marrow transplantation (BMT) was performed in a 34-year-old man for non-Hodgkin's lymphoma. Two years before bone marrow harvest, pulmonary sarcoidosis was diagnosed in the donor. After steroid therapy, disease of the donor was in clinical remission with only minor radiological signs at the time of BMT. On day 90 after BMT, active sarcoidosis was diagnosed in the recipient. Besides radiologic signs and increased angiotensin converting enzyme levels, diagnosis was proved by characteristic histologic changes in lung and liver biopsies. Immunosuppressive therapy was changed from high dose cyclosporine to high dose methylprednisolone and symptoms promptly resolved within 10 weeks. This case indicates the possibility of transmission of sarcoidosis by marrow transplantation.

Adult↗
PubMed1994

[Intracranial MR angiography].

Magnetic resonance angiography (MRA) is gaining wide acceptance as a screening modality for the intracranial vasculature. Previous reports have demonstrated that MRA is capable of accurately depicting the normal vascular anatomy and anatomic variants. To date various techniques have been applied in the evaluation of vaso-occlusive disease, aneurysms, arteriovenous malformations and venous sinus thrombosis. Recent technical developments have significantly improved spatial resolution and vascular contrast and will further enhance its routine clinical use. The purpose of this essay is to summarize the technical approaches, clinical role and limitations of MRA as they apply to the intracranial circulation.

Blood Flow Velocity↗
PubMed1994

[Infratentorial brain tumors in childhood and adolescence--value of MRT in initial and recurrence diagnosis].

MRI is the current method of choice for the diagnosis of infratentorial tumors in children and adolescents. The present article discusses the individual tumor entities on the basis of their magnetic resonance imaging characteristics in the patient pool of 1991/1992. New magnetic resonance imaging procedures are considered for infratentorial vascular anomalies. In addition to its use in the primary diagnosis, the significance of MRI for the detection of recurrences is discussed. Problems arising after prior surgery and irradiation as well as metastasization through CSF pathways are also mentioned.

Adolescent↗
PubMed1994

[Hypodense oral intestinal contrasting for the diagnostic optimization of abdominal computed tomograms in children].

37 children were examined for diagnostic improvement of the oral intestinal contrasting images in abdominal computed tomography with a hypodense solution of mannitol (n = 23) in comparison with a suspension of BaSO4 (n = 14). Because of the hypodense intestinal contrasting images the artifacts of the images induced by the bordering surface could be reduced, the condition of fullness of the intestine and the judgement of the intestinal wall improved. The parenchymatous organs and points of abdominal lymph nodes could be defined and judged more easily through the hypodense contrasting images. On the whole the picture quality of the computed tomography of the young child could be increased with the hypodense solution of mannitol.

Administration, Oral↗
PubMed1994

[Cytomegalovirus infection of the intestinal tract. Computed tomographic findings in AIDS patients].

To check the value of computed tomography (CT) in the diagnosis of cytomegalovirus (CMV) infection of the intestine, CT findings in ten patients with coloscopically proven CMV infection were reviewed. All patients were chronically ill men with AIDS. In nine of the ten cases CT scans of the small intestine and/or colon disclosed abnormalities. The predominant alteration (9/9) was a symmetric wall thickening in the bowel segments involved (10-30 mm). The location and extent showed good agreement with the inflammatory areas seen on coloscopy. The cecum and terminal ileum were the regions most frequently affected. In seven of the nine patients with CT abnormalities CT revealed pericolonic inflammation, particularly around the cecum. Lymph nodes were increased but not enlarged. Comparison of the findings in intestinal CMV infection with those in other AIDS-related diseases suggests that CT may be to limit the differential diagnosis. Abdominal CT serves as suitable primary imaging modality for the initial evaluation of patients with AIDS and abdominal symptoms of unknown etiology.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Optic neuropathy in type-1 diabetes and acetylsalicylic acid-refractory thrombocyte activation].

A 26-year-old female with severe complications from type I diabetes mellitus of 17 years' duration (proliferative retinopathy, nephropathy with renal failure and nephrotic syndrome) developed rapid deterioration of vision in the right eye to 6/60 over a period of several weeks. There were no other neurological signs. Ophthalmological examination showed no worsening of the diabetic retinopathy, but the presence of bilateral optic atrophy, confirmed by visual evoked potentials. CT scan did not reveal any retrobulbar process, and MR scans of both the optic nerves and the visual pathways were unremarkable. The clinical features and the investigations pointed towards ischaemic optic atrophy. Detailed platelet studies showed intravascular platelet activation and an ADP-inducible increase in aggregation, although thromboxane formation was almost absent because of cyclooxygenase inhibition by acetylsalicylic acid. These findings suggest that the ischaemia was due to microcirculatory disturbances secondary to diabetic microangiopathy and platelet hyperreactivity.

Adult↗
PubMed1993

[Functional imaging of the brain using low dose gadolinium-DTPA and Turbo-FLASH sequences].

A method for measuring regional blood volume and flow is described based on the reduced relaxation time following intravenous injection of Gd-DTPA. The optimal Gd dose and other parameters were first determined using turbo-flash sequences and a dilution phantom. A single maximum was found for a Gd-DTPA concentration of 4 mmol/l. Taking account of normal heart/time volumes and in order to stay below this arterial value Gd-DTPA was injected as a bolus at the rate of 1 mmol/sec. From the phantom measurements there appears to be a functional connection between measured signal intensity and Gd concentration. The method was applied to 15 patients with cerebral tumours, using altogether 26 perfusion examinations. The results from 4 patients are given as examples; in these, blood volume and flow were calculated for each pixel in a 128 x 128 matrix. It was found that the Gd-DTPA injected is sufficient to be shown with certainty in the grey and white matter and that this is able to demonstrate pathological changes in a functional manner. Comparison with Gd-DTPA doses such as are used for morphological imaging (typically, 10 mmol corresponding to 0.1 mmol/kg body weight) has shown that doses above 1.6 mmol may lead to distortion of the concentration curves.

Aged↗
PubMed1993

[Diabetic osteoarthropathy (DO) of the forefoot].

In patients suffering from diabetic osteoarthropathy, a total of 97 forefeet were evaluated concerning their bone tissue and soft tissue transformations. The most prevalent forms of demineralisation were circumscribed osteoporosis (21%) and diffuse osteoporosis (20%). Subluxations (6.2%), dislocations (2.1%), erosions (8.3%), marginal usures (11.3%) or cysts of the bone (11.3%) were seen only rarely. Extensions of the articular space (10.3%) were more prevalent than disappearances of the articular space (4.1%). The MTP (26.8%) and PIP joints (10.3%) were confirmed to be preferred localisations. A sudden loss of articular surface (25%) and a fast transition to mutilation (23.5%) show the increasing tendency of the fast transition to advanced stages of destruction by omitting the earlier stages.

Adult↗
PubMed1993

[The hemodynamics and anatomy of the circle of Willis. The technic and clinical value of selective MR angiography].

This study evaluates the usefulness of MR angiography in analysing the individual collateral flow dynamics and anatomy of the circle of Willis in 56 patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar area was performed by means of presaturation up to the brain-supplying arteries at the level of the middle neck (angled presaturation slabs). Results obtained with selective and non-selective MRA in 56 consecutive patients were compared with the findings at transcranial Doppler ultrasonography and arterial angiography. Ischaemic cerebral infarctions were classified by computerized tomography and correlated with the results of collateral flow analysis: Sensitivity of selective MRA in detecting intracranial collateral flow via anterior or posterior communicating artery was 96 and 97%, respectively; sensitivity in depicting extracranial transorbital flow was lower (71%). Non-selective MRA was 100% sensitive in detecting a non-filling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Slow flow infarctions occurred more frequently in patients with transorbital and posterior-to-anterior collateral flow than in patients with collateral flow via anterior communicating artery.

Angiography↗
PubMed1993

[Bilateral pneumothorax, pneumomediastinum and pneumoperitoneum following unilateral percutaneous lung biopsy].

Case report on a 53-year old male patient; after transthoracic resection of the oesophagus a unilateral percutaneous biopsy of a newly developed round focus of the lung led to a bilateral pneumothorax (as well as a pneumomediastinum and a pneumoperitoneum). After transthoracic surgery the described alterations have also to be taken into account as possible complications of a unilateral percutaneous lung-biopsy.

Biopsy↗
PubMed1992

[Renal stent implantation. The current indications, 2-year results and the possibilities for percutaneous stent recovery].

Use of the Strecker flexible balloon-expandable tantalum stent for treatment of renal artery stenosis after failed angioplasty or transaortic thrombendarterectomy was evaluated in 18 patients (17 hypertensive, 1 normotensive). Right (n = 10) and left (n = 6) renal arteries were involved; in 2 patients renal artery stenosis had developed after kidney transplantation. Indications for stent placement were inadequate immediate postangioplasty response (n = 16), and obstructing intimal flaps following transaortic endarterectomy (n = 2). Stent placement was technically successful (less than 20% residual stenosis) and patency was preserved in 14 patients. Mid-term results (mean, 12-13 months) of 11 patients showed restenoses (greater than 50%) in 2 patients, and improvement of hypertension in 8 patients. The Strecker stent may be helpful in treating residual stenosis after failed revascularization procedures of the renal arteries, although long-term efficacy of stent placement will not be known until trials with more subjects and longer follow-up periods are completed.

Adult↗
PubMed1992

[Color-coded duplex sonography (angiodynography)].

Colour-coded duplex sonography is a relatively new method of diagnostic imaging. Compared with conventional duplex sonography it has advantages in respect of simplicity and speed in several applications. The main application of colour-coded duplex sonography is for the detailed demonstration of a limited area. A comprehensive demonstration of blood vessels remains the province of angiography. Clinical applications include vessels in the neck, lateral soft tissue anatomy of the neck, arteries and veins in the extremities, haemodialysis shunts, transplanted kidneys and acute abnormalities in the scrotum. In the abdomen the method is of only limited application.

Abdomen↗
PubMed1992

[The value of 2- and 3-dimensional computed tomography in the diagnosis and classification of midfacial and orbital fractures].

The value of 2D- and 3D-computed assisted tomography in detecting and classifying midfacial fractures and craniofacial deformities acquired by gunshot injuries was assessed in 123 resp. 26 patients and compared with the postoperative results. In a comparative study 37 patients were prospectively examined by pluridirectional tomography. Examinations of a macerated skull were performed to optimize 3D investigation technique. High resolution CT proved to be the most reliable technique in detecting midfacial fractures and associated soft tissue injuries. 3D-imaging of bony surfaces allowed clear demonstration of fraction extent and fragment displacement without offering additional detail information. 3D-based computer-assisted manufacturing of individual models facilitated surgical planning of complex midfacial injuries.

Adolescent↗