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Biomedical subjects

F Schellhammer

Publications and source records attributed to F Schellhammer.

At least 19 recordsLinked to original sources
PubMed2007

[Nonocclusive ischemia of the right colon].

BACKGROUND: Nonocclusive disease (NOD) is known to be a common cause of ischemic colitis, which is frequently underestimated. MATERIAL AND METHODS: A computer-assisted search of radiological reports at our institute over a period of 18 months, describing ischemic colitis of the ascending colon with an unimpaired perfusion of the superior mesenteric artery, was performed. RESULTS: A retrospective analysis of the clinical and radiological data of 14 patients was performed. In ten cases colonic ischemia was confirmed clinically or intraoperatively. Most of our patients needed intravenous catecholamines due to severe hypotension. However, no significant radiographic predictors could be identified. CONCLUSION: Awareness of NOD seems to be crucial. Especially in cases of acute abdominal pain associated with severe hypotension, renal insufficiency, or pancreatitis, one should include NOD as a differential diagnosis at an early stage.

Abdominal Pain↗
PubMed2005

Asymptomatic aneurysm of the subclavian vein.

Venous aneurysms are rare entities whose etiology remains unknown. We report an incidental observation of an asymptomatic, saccular aneurysm of the subclavian vein and discuss the possible origin and clinical impact, with special remarks on venous interventions.

Adult↗
PubMed2003

Do radiologists want/need training in cardiopulmonary resuscitation? Results of an Internet questionnaire.

PURPOSE: Prompt and effective cardiopulmonary resuscitation (CPR) decreases morbidity and mortality following cardiopulmonary arrest. Radiologists are frequently confronted with severely ill patients, who may deteriorate at any time. Furthermore, they have to be aware of life-threatening reactions towards contrast media. This study was designed to assess experience and self-estimation of German-speaking radiologists in CPR and cardiac defibrillation (CD). MATERIAL AND METHODS: 650 German-speaking radiologists were audited by a specially designed questionnaire, which was sent via e-mail. The answers were expected to be re-mailed within a 2-month period. RESULTS: The response rate was 12.6%. 72.8% of the responders had performed at least 1 CPR (range 9.5 +/- 13.1) and 37% at least 1 CD. 67.9% had had opportunities to attend training courses, which had been utilized by 41.8% of them. The last training of the responders was more than 2 years ago in 69.2% and more than 5 years ago in 37%. Of all responders 75.6% expressed the need for further education. CONCLUSION: The small response rate indicates the small importance of CPR in the subpopulation surveyed. The vast majority of the responders, however, showed interest in basic and advanced life support and advocated regular updates. It seems reasonable that radiological departments themselves should organize courses in order to cope with their specific situations.

Attitude of Health Personnel↗
PubMed2002

Combined stent implantation and embolization with liquid 2-polyhydroxyethyl methacrylate for treatment of experimental canine wide-necked aneurysms.

The purpose of the study was the evaluation of 2-polyhydroxyethyl methacrylate (2-P-HEMA) for endovascular liquid embolization of experimental side-wall aneurysms following stent protection in a canine model. The swelling behaviour and polymerization characteristics of 2-P-HEMA in different solutions were investigated in vitro. Different methods for applications were tested in a latex aneurysm model under pulsatile flow conditions. Twenty broad-based carotid side-wall aneurysms were microsurgically produced in five dogs. Four weeks after surgery self-expandable nitinol stents were placed, covering the orifice of the aneurysms. 2-P-HEMA was injected via a microcatheter, which was positioned through the meshwork of the stent. Control angiography was performed immediately after treatment and after 1, 6 and 9 months. In-vivo stent placement succeeded in all but one case. Two aneurysms occluded spontaneously after stent placement. Combined embolization of 17 aneurysms using a stent and 2-P-HEMA was performed. Eleven aneurysms could be primarily completely occluded (65%). A small remaining neck was evident in six aneurysms. Efflux of 2-P-HEMA during the process of embolization was observed in seven aneurysms, due to an excess volume of 2-P-HEMA. The excessive 2-P-HEMA led to significant vessel stenosis in two cases. Two carotid arteries (three treated aneurysms) occluded after 1 month, due to insufficient anticoagulation management. Histological examination of embolized aneurysms revealed no foreign-body or inflammatory reaction. A smooth neo-intimal layer covered the stented vessel segment. Liquid embolization of side-wall aneurysms with 2-P-HEMA is technically feasible. Embolotherapy of aneurysms with liquid agents still has the risk that embolic material will exit even when it is stent-protected. To avoid this problem, stents with smaller strut diameter and/or additional balloon-protection are required. The inert 2-P-HEMA seems to be a promising agent for combining techniques of aneurysm treatment.

Aneurysm↗
PubMed2002

[Palmar lunate dislocation].

UNLABELLED: Palmar lunate dislocation as the end stage of a perilunate dislocation is a very uncommon injury. Having treated 19,534 hospitalized patients between 1 January 1986 and 1 October 2001 the diagnosis was recorded in four male trauma patients (33, 36, 37 and 62 years old). Among the operatively treated carpal dislocations and carpal fracture dislocations those of the lunate were seen in five per cent. The dislocation was caused in by an acute hyperextension injury resulting of falls from heights in three cases, and of a motorcycle accident in a further case. In two of these cases a complete palmar lunate dislocation was analysed that were produced by fall from seven meters heights of a young craftsman and by accident of a motorcyclist. First using a longitudinal palmar approach in both cases a revision of the hemorrhagic carpal canal was performed urgently, the largely denuded lunate was reduced and the repair of identified ligamentous structures was performed by means of sutures respectively suture anchors. Reduction was stabilized with Kirschner wires. Afterwards performed computed tomography identified the result of reduction and associated defects (subluxation distal radioulnar joint). In one patient a soft tissue infection prevented the dorsal ligamentous repair. In spite of a consequent after-treatment and a good functional result a scapho-lunate dissociation was proved. An avascular defect of the lunate could be excluded by magnetic resonance imaging. In case of a secondary performed dorsal repair a persisting carpal stabilization with a satisfactory functional result could achieved. At second hand an advanced carpal collapse was proved. CONCLUSIONS: If reduction cannot be achieved by closed manipulation or a loss of reduction is shown, open reduction is indicated first by a palmar approach. An additional dorsal ligamentous repair seems to be necessary. Transfixation by Kirschner wires and suture anchors stabilize the restored anatomic relationships. Wrist immobilization in a cast for at least eight weeks is recommended. Although ligamentous insufficiency, osteoarthrosis and avascular necrosis are often proved, functional results are satisfactory.

Adult↗
PubMed2002

Nitinol micro-forceps for retrieval of intravascular objects: first in vitro experiences.

RATIONALE AND OBJECTIVE: With the progress of interventional procedures the need for retrieval of iatrogenic materials increases. Here we introduce a new nitinol micro-forceps for retrieval of intravascular objects and report our first in-vitro experiences. MATERIALS AND METHODS: In a tube model simulating arterial anatomy a total of eight endovascular coils were removed from the "carotid artery" using a "trans-femoral" approach. Additionally, the withdrawal of grasped coils through vascular sheaths of F-5, F-6, F-8, F-12 was observed (n = 4/seize). RESULTS: Seven of 8 coils were successfully grasped. Loss of one coil occurred during retrieval. Withdrawal of coils through a vascular sheath was possible only when the coil was grasped at one of its ends. DISCUSSION: The nitinol micro-forceps proved to be a potential tool in endovascular retrieval of foreign objects especially in small caliber vessels. However, further technical modifications are necessary to improve maneuverability and grasping strength.

Alloys↗
PubMed2001

In vitro evaluation of intravascular stent artifacts in three-dimensional MR angiography.

RATIONALE AND OBJECTIVES: To evaluate the intraluminal signal characteristics of various stents and stent-grafts in contrast-enhanced three-dimensional MR angiography (3D MRA) in vitro. METHODS: Fourteen stents made of different materials (steel, nitinol, tantalum, cobalt-based alloy, polyethylene) and six stent-grafts were implanted in plastic tubes simulating the common iliac artery. The tubes were filled with gadopentetate dimeglumine in water at a concentration of 25 mmol/L and positioned in a plastic container filled with water. For imaging, the container was placed in the center of the magnet, parallel, orthogonal, and diagonal to the z axis. A 3D gradient-echo sequence (T1-FFE) was acquired with the following parameters: repetition time 5.3 ms, echo time 1.6 ms, flip angle 50 degrees, slice thickness 1.5 mm, and acquisition matrix 256 with zero filling to 512. To evaluate the influence of the frequency-encoding gradient on the appearance of the artifacts, stents were examined with their axes oriented in all three directions both with the frequency-encoding gradient in the feet-head and right-left directions. The size and pattern of stent-related artifacts were evaluated semiquantitatively for each measurement. RESULTS: Five different components of artifacts could be distinguished: homogeneous signal reduction inside the stent, narrowing of the stent lumen, structures of various shapes inside the stents, signal reduction or signal increase at the ends of the stents, and shift of the intraluminal signal orthogonal to the longitudinal axis of the vessel. The size of the artifacts depended heavily on the material of the stent. The polyethylene stent showed no artifacts, the tantalum stent only minor artifacts. Nitinol stents were characterized by artifacts at both ends and signal reduction intraluminally. Stents made of steel demonstrated the strongest artifacts, characterized by almost complete signal loss intraluminally. The characteristics of the artifacts of all stents depended on the direction of the stent relative to the frequency-encoding gradient. CONCLUSIONS: Three-dimensional MRA follow-up after stent placement may be applicable for stent patency evaluation in all instances. However, grading of stenoses seems to be unrealistic in steel stents and in most nitinol stents.

Arteries↗
PubMed2000

[Indications and rate of repeat studies in the color duplex department of a radiology university clinic].

PURPOSE: Who refers patients for a color duplex ultrasonography (CDUS) in the routine work of a radiological university department and how frequent are repeat examinations? MATERIAL AND METHODS: 1110 patients had at least one CDUS examination between 5/97 and 5/98. The specialities of the referring physicians/primary examiners and the inpatient or outpatient status of the patients were documented at the first consultation. Additionally the patients were asked by the medical staff, whether, how often, and by whom ultrasonographic, CT, or MR examinations of the same organ system had been carried out during the last 4 weeks without evidence of any clinical changes. RESULTS: 97% of the 1118 patients were referred by one of the university departments. The arterial system was exclusively investigated in 58% and the venous system in 29% of the cases. 81% of the 651 arterial examinations were requested by the Departments of Vascular/Cardiac Surgery and Radiology. 75 repeated ultrasonographic examinations were documented in 67 (6%) of the 1118 consultations. Repetitions were documented in 8% of the arterial and in 3% of the venous examinations. X-ray angiographies were already done or planned in 105 of the 625 arterial CDUS (16%). Ultrasonographic referrals with parallel phlebographies (1% of 320 venous indications) as well as parallel CT and MR examinations (1% of the 1118 consultations, respectively) were the exception. CONCLUSIONS: In the described setting, CDUS was mainly used to assess the arterial vascular system prior to vascular surgery and radiological interventions. Repeat ultrasonographies alone (6%) and parallel examinations altogether (14%) were observed less frequently than expected.

Adolescent↗
PubMed2000

[Primary intracranial germinoma. Problems in determining the diagnosis exemplified by 4 cases].

Primary intracranial germinoma is a possible cause of "idiopathic" diabetes insipidus in childhood and adolescence. The histopathologic appearance can be similar to inflammation, and may delay the final diagnosis. Further diagnostic difficulties are demonstrated by the use of anamnestic and clinical data as well as diagnostic imaging findings in four children with histologically proven primary intracranial germinoma.

Adolescent↗
PubMed1999

[Frequency of repeated examinations in the ultrasonographic section of a radiological university department].

PURPOSE: What is the percentage of repeat examinations in the ultrasonographic section of a radiological university department? METHODS: All 4116 patients, who were first examined in the sonographic section of the Radiologic Department of the University of Cologne from 5/97 to 5/98, were asked by the medical staff, whether, how often and by whom ultrasonographic, CT or MR examinations of the same organ system had been carried out during the last 4 weeks without evidence of clinical changes. The data were documented using a structured questionnaire. RESULTS: Sonographic repeated examinations documented in 443 (10.8%) of the 4116 consultations. The proportion of in- to outpatients with repeat examinations was 26.0% to 74.0%. Contrarily, the repeated ultrasonographies were done by practitioners in 62.3% and by the university staff in 33.2% (radiology 48.2%). With regard to the 4116 consultations, the abdomen (81.1%) was the organ system most often examined repeatedly. Computed tomographies were already done or planned in 305 of 4116 patients (7.4%) and MR-tomographies were already done or planned in 57 patients (1.4%). CONCLUSION: The rate of repeated ultrasonographic examinations in a radiological university hospital was 19.6%.

Abdomen↗