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C Paetzel

Publications and source records attributed to C Paetzel.

15 recordsLinked to original sources
PubMed2006

In vitro evaluation of stent patency and in-stent stenoses in 10 metallic stents using MR angiography.

In vitro study to investigate the suitability of contrast enhanced magnetic resonance angiography (CEMRA) for determination of stent patency and grading of in-stent stenoses in 10 metallic stents. The Acculink carotid, DynaLink, Easy Wallstent, JostentSelfX XF, Luminexx, Omnilink, sinus-SuperFlex, SMART, Symphony and ZA stent were separately placed in a vascular phantom. Dedicated stenoses inside the stents generated a concentric lumen narrowing of 50%. CEMRA was performed for each stent. Signal loss inside the stents and artificial lumen narrowing were assessed objectively using the evaluation software of the MR imager. Moreover, three blinded observers determined visibility of stent patency and in-stent stenoses subjectively on a 3-point scale and graded in-stent stenoses. Loss of signal intensity within the stent lumen ranged between 90% (Wallstent) and 5% (ZA), artificial lumen narrowing between 56% (Symphony) and 22% (ZA). For the Symphony and Wallstent, visibility of patency and in-stent stenoses was impaired and the observers' grading exaggerated the degree of stenoses (by 23% and 33%, respectively). For the remainder of stents, patency and stenoses were visible and stenoses were graded accurately (less than 10% discrepancy from reference standard). In this in vitro study, eight of 10 stents presented with MRI characteristics which enabled determination of stent patency and accurate grading of clinically relevant in-stent stenoses.

Artifacts↗
PubMed2006

Intra-arterial MR angiography in the iliac system: initial clinical experience with 25 patients.

The aim of this study was to evaluate intra-arterial magnetic resonance angiography (MRA) of the iliac arteries. Therefore, 25 consecutive patients (17 male, 8 female) suffering from symptomatic occlusive disease of the lower limbs were investigated prospectively. Catheter angiography was performed before MRA and served as the standard of reference. Contrast-enhanced intra-arterial MRA was performed using a 1.5 Tesla MRI system. Contrast agent (gadodiamide) was injected by a conventional pigtail-shaped angiography catheter placed in the abdominal aorta. Vascular lesions were assessed by four investigators. The degree of stenosis was compared with the findings of conventional catheter angiography. Additionally, the diagnostic quality of the MR angiograms was assessed by the investigators using a semi quantitative five-point scale. All lesions shown by catheter angiography were detected and correctly localized by intra-arterial MRA. MR angiograms exhibit a specificity of 95% and a sensitivity of 96% for stenoses of 50% or more. The diagnostic quality of the images was judged from good to excellent, on average. Intra-arterial MRA exhibits a specificity and sensitivity comparable with intravenous angiography. The image quality appears to be adequate for supporting MR-guided vascular intervention.

Adult↗
PubMed2005

Intra-arterial magnetic resonance angiography of the iliac arteries: clinical experience using two different protocols.

PURPOSE: To assess the feasibility of intra-arterial magnetic resonance angiography (iaMRA) with two different protocols. MATERIAL AND METHODS: Twenty patients were prospectively examined after digital subtraction angiography. Contrast-enhanced iaMRA was performed using a 1.5T magnetic resonance imaging (MRI) system. Contrast agent (gadodiamide) was injected through a conventional angiography catheter placed in the abdominal aorta. The patients were randomized into two groups each comprising 10 patients. Group 1 was examined with a FLASH-3D (fast low-angle shot) sequence, allowing the center of the k-space to be acquired 0.5 s after initiation of the measurement. Group 2 was examined with the identical sequence, but the center of the k-space was acquired after 8.7 s. The increase in the intravascular signal intensity was determined and the diagnostic value of the angiograms was independently scored by 4 investigators using a 5-point scale. RESULTS: Nineteen of 20 MRAs were scored as diagnostic; only 1 was scored as non-diagnostic by 2 observers. The diagnostic value of the angiograms of group 2 was judged superior to that of group 1 owing to a more homogeneous intravascular contrast distribution. CONCLUSION: Intra-arterial MRA is feasible. The diagnostic value of angiograms using a flash sequence with center of the k-space acquisition after 8.7 s ranged from good to excellent. This sequence is appropriate for iaMRA of iliac arteries to support MR guided intervention.

Adult↗
PubMed2004

Feasibility of MR-guided angioplasty of femoral artery stenoses using real-time imaging and intraarterial contrast-enhanced MR angiography.

PURPOSE: To show the feasibility of magnetic resonance (MR) for guided interventional therapy of femoral and popliteal artery stenoses with commercially available materials supported by MR real-time imaging and intraarterial MR angiography. MATERIALS AND METHODS: Three patients (1 female, 2male), suffering from symptomatic arterial occlusive disease with stenoses of the femoral (n = 2) or popliteal (n = 1) arteries were included. Intraarterial digital subtraction angiography was performed in each patient pre- and post-interventionally as standard of reference to quantify stenoses. The degree of the stenoses reached from 71 - 88 %. The MR images were acquired on a 1.5 T MR scanner (Magnetom Sonata; Siemens, Erlangen, Germany). For MR-angiography, a Flash 3D sequence was utilized following injection of 5 mL diluted gadodiamide (Omniscan; Amersham Buchler, Braunschweig, Germany) via the arterial access. Two maximum intensity projections (MIP) were used as road maps and localizer for the interactive positioning of a continuously running 2D-FLASH sequence with a temporal solution of 2 images per second. During the intervention, an MR compatible monitor provided the image display inside the scanner room. Safety guidelines were followed during imaging in the presence of a conductive guidewire. The lesion was crossed by a commercially available balloon catheter (Wanda, Boston Scientific; Ratingen, Germany), which was mounted on a 0.035" guidewire (Terumo; Leuven, Belgium). The visibility was provided by radiopaque markers embedded in the balloon and was improved by injection of 1 mL gadodiamide into the balloon. After dilation, the result was checked by intraarterial MR angiography and catheter angiography. RESULTS: The stenoses could be correctly localized by intraarterial MR angiography. There was complete correlation between intraarterial MR angiography and digital subtraction angiography. The combination of guidewire and balloon was visible and the balloon was placed correctly to cover the entire stenoses. Balloon dilation reduced the degree of stenosis about 45 % on average. A prolonged dilation was necessary in one patient due to a relevant residual stenosis, which was recognized by intraarterial MR angiography. CONCLUSION: MR-guided balloon dilatation of femoral and popliteal artery stenoses supported by real time imaging and intraarterial MR angiography is feasible with commercially available materials in the above mentioned way.

Aged↗
PubMed2004

Clinical and angiographic outcome after interventional treatment of the iliac arteries with a new carbofilm coated stent: preliminary results.

PURPOSE: To evaluate the handling, the procedural success rate and the six-month outcome of a new Carbofilm coated balloon-expandable stent in iliac artery lesions. MATERIALS AND METHODS: In a prospective study, 46 stenoses and 2 occlusions of the iliac arteries were primarily stented in 30 patients with the Isthmus CarboStent (Sorin Biomedica Cardio S.p. A., Saluggia, Italy). The ankle-brachial index (ABI) at rest was determined before intervention and at the six-month follow-up visit. Iliac angiography, including intraarterial pressure measurement, was performed before intervention, post-procedurally and at the follow-up visit. RESULTS: All lesions were treated with procedural success. The mean degree of all stenoses was 73.9 % +/- 14.6 before and 2.4 % +/- 8.2 after intervention. The mean pressure gradient was 15.6 mm Hg +/- 10.1 before and 2.5 mm Hg +/- 2.7 after treatment. No or only a mild restenosis developed in 27 patients. The mean ABI increased from 0.64 +/- 0.21 to 0.86 +/- 0.33 and the mean pressure gradient was 2.7 mm Hg +/- 5.4 at the six-month visit. The six-month patency rate was 97.9 %. Three patients showed acute stent thrombosis due to an insufficient postprocedural antiplatelet regimen. DISCUSSION: The Isthmus CarboStent is a safe and easy to handle balloon-expandable stent for interventional therapy of iliac artery lesions. The six-month patency rate is good. Despite its Carbofilm coating, postprocedural antiplatelet therapy is necessary.

Administration, Oral↗
PubMed2003

[Evaluation of radiological teaching programs in the Internet].

PURPOSE: Evaluation of web based training programs, which can be contacted from the homepages of radiological departments of German universities. MATERIAL AND METHOD: From June 2000 to January 2002 the 75 web based training programs of 57 providers,which can be contacted from the web pages of the radiological departments of German universities were evaluated in a prospective study. A medical student experienced in using the world wide web examined each training program three times in an interval of six months using the following criteria: availability of the web sites, target group, kind of training program, contents and structure and the technical solution. RESULTS: 51 of the 57 the homepages were fully available at each visit. 64 of the 75 web based training programs which could be connected from these sites were available at all three visits.One program was only partially available at one spot check. 8 of the 75 programs were designed for physicians and medically trained personal, 23 were made for medical students and 44 addressed both target groups (partially more than once mentioned). The number of the presented cases ranged between one single and 3700. In 31 of 75 training programs links to other teaching files were found. A complete presentation of cases was presented by 48 of the 75 web sites.5 of the 75 web sites offered physiological images for comparison. In 20 training programs the pathological changes were optically marked in the x-ray images. A logical and didactical structure was found in 24 teaching files, 14 gave the possibility to check the learning results. No provider made use of the possibility to pass credits to the students or physicians account with regard to official training programs. Multimedia techniques were used in 15 training programs.43 sites used data reduced preview images (thumbnails). The latest update of the site is mentioned in 55 of the 75 web sites. 19 of 57 providers had either no possibility of contact or did not answer to an e-mail. CONCLUSION: From the homepages of the departments of diagnostic radiology of German universities 75 teaching files can be contacted. There is a great variety in quantity and quality. Most sites offer collections of cases. A web based training program which is comparable in quality to a CD-ROM teaching program could not be found. No program used the possibility to give credits to the users with regard to official training programs.

Computer-Assisted Instruction↗
PubMed2003

[Evaluation of a hemostatic device with percutaneous collagen application (VasoSeal) compared to a mechanical compression system (Compressar) after transfemoral catheterization of patients suffering from arterial occlusive disease].

PURPOSE: Comparison of the efficacy of VasoSeal and a mechanical compression system (Compressar) for percutaneous hemostasis after femoral arterial catheterization of patients with arterial occlusive disease. MATERIALS AND METHODS: 60 patients underwent either diagnostic angiography or interventional procedures. The level of anticoagulation, blood pressure, and activation clotting time were recorded, and the time to hemostasis after sheath removal was measured. VasoSeal application was considered "successful" if the compression time was less than two minutes. On the subsequent day as well as 4 months later, color coded Doppler ultrasound was performed to register treatment success and potential (late) complications. RESULTS: 57 patients qualified for inclusion in this study. In 21 of the 26 patients who underwent the procedure with the VasoSeal, immediate hemostasis was achieved within 1.75 minutes. In all 31 patients who had the Compressar applied, hemostasis was successful with a mean compression time of 17.4 minutes. Thus, VasoSeal significantly reduced hemostasis time irrespective of anticoagulation status, but it had a much higher incidence of minor local complications (bleeding, hematoma) compared to the control group (34.6 % vs. 5.8 %). The technical success was lower with VasoSeal than with Compressar (81 % vs. 100 %). Both groups had no severe or late complications. CONCLUSION: According to our results, VasoSeal does not provide a suitable alternative compared to the effective, safe and cheap application of Compressar as a hemostatic device.

Adult↗
PubMed2003

[Indirect MR-arthrography of the shoulder-value in the detection of SLAP-lesions].

PURPOSE: A prospective study to assess the value of indirect magnetic resonance-arthrography (MR-Arthro) in the detection of lesions of the superior labrum (SLAP-lesions). MATERIALS AND METHODS: Unenhanced magnetic resonance imaging (MRI) and indirect MR-Arthro of the shoulder were performed in 35 patients (9 females and 26 males) with a history of acute or chronic shoulder disorder. The images of unenhanced MRI and indirect MR-Arthro were analyzed independently from each other for the occurrence of SLAP-lesions and the findings correlated with the arthroscopic results. For arthroscopy, MRI and MR-Arthro, the SLAP-lesions were categorized based on the classification system of Snyder. RESULTS: SLAP-lesions were diagnosed by arthroscopy in 22 of 35 patients (63 %). 9 of the 22 lesions (41 %) were classified as type 1, 9 (41 %) as type 2, three (13.5 %) as type 3 and one (4.5 %) as type 4. Using unenhanced MRI sensitivity, specificity and accuracy in the detection of SLAP-lesions were calculated to be 73 %, 85 % and 77 %. Indirect MR-Arthro showed a sensitivity of 91 %, a specificity of 85 % and an accuracy of 89 %. Unenhanced MRI revealed correlation to the arthroscopic classification in 9 of 22 cases (41 %) and indirect MR-Arthro in 18 of 22 cases (82 %). CONCLUSION: Indirect MR-Arthro is a non-invasive method which offers excellent sensitivity in the diagnosis of SLAP-lesions. It provides important preoperative informations with regard to the exact location and extent of a tear.

Adult↗
PubMed2002

[Contrast-enhanced MR angiography in the routine work-up of the lower extremity arteries].

PURPOSE: Prospective evaluation of the effectiveness of contrast-enhanced moving-table magnetic resonance angiography (CE-MRA) as the sole routine tool for the diagnosis of peripheral arterial occlusive disease and determination whether it can replace catheter arteriography. SUBJECTS AND METHODS: In a time period of 23 weeks, 100 consecutive patients were evaluated. A total of 112 contrast-enhanced moving-table MR angiograms were performed at 1.5 Tesla. A dedicated vascular coil system was used. It was evaluated in which cases MR angiography was sufficient to determine the treatment plan and in which cases limited quality required additional examinations. RESULTS: In 93.75 % (105/112) of all examinations, the treatment plan was determined by MRA as the sole diagnostic tool. Twenty-two patients underwent surgery or percutaneous angioplasty based on MRA findings. Additional examinations due to impaired quality were performed in seven (6.25 %) cases: two MR angiographies of the pelvic arteries, one MR angiography of the calf, and four selective arteriographies because of venous overlay at the calf. CONCLUSION: Contrast-enhanced MR angiography can take the place of catheter angiography in the routine work-up of patients with peripheral arterial occlusive disease. Further assessment might be necessary in five to ten percent of the cases when the diagnostic quality is inadequate, mostly due to venous overlay in the lower leg.

Adult↗
PubMed2002

[Percutaneous therapy of inoperable biliary stenoses and occlusions with a new self-expanding nitinol stent (SMART)].

OBJECTIVE: To evaluate the treatment of malignant biliary stenoses and occlusions using a new stent. METHODS: In a prospective study, 25 patients with malignant obstructive jaundice were treated with SMART(R) stents. The handling and the quality of stent expansion were documented. Stent function was assessed 2 - 4 days after intervention by cholangiography and laboratory tests. A follow-up was performed three months, after stent placement. RESULTS: All lesions were treated successfully, with a total of 35 stents implanted. In 14 patients a further balloon dilatation was performed after stent placement (8 - 10 mm diameter/ 40 - 80 mm length). The mean serum bilirubin level decreased significantly from 11.6 mg/dl to 4.6 mg/dl after intervention (p < 0.05). The follow-up showed a mean serum bilirubin level at 4.0 mg/dl. In 4 cases (16 %) a further intervention (PTCD or stent) was performed. Six patients died due to tumor progression. The stents proved to be patent in 79 % (n = 15) of patients alive at the time of follow-up. CONCLUSIONS: Placement of the SMART stent for the therapy of malignant biliary lesions yields good technical and clinical results.

Aged↗
PubMed2001

Dynamic magnetic resonance imaging defecography: a diagnostic alternative in the assessment of pelvic floor disorders in proctology.

PURPOSE: Standard diagnostic proctologic procedures in the assessment of pelvic floor disorders include clinical evaluation and endoscopy. Particular aspects of combined pelvic floor disorders, especially those involving more than one pelvic compartment, may remain undetected without additional technical diagnostic procedures such as videoproctoscopy, cinedefecography, or colpocystodefecography. The aim of the study was to review the potentials of dynamic magnetic resonance imaging defecography to elucidate the underlying anatomic and pathophysiologic background of pelvic floor disorders in proctologic patients. PATIENTS AND METHODS: Dynamic magnetic resonance imaging defecography was performed in 20 Patients (13 females) with main diagnoses such as rectal prolapse or intussusception, rectocele, descending perineum, fecal incontinence, outlet obstruction, and dyskinetic puborectalis muscle after clinical evaluation. The investigation was performed on a 1.5 T-magnetic resonance imaging machine in supine position. The rectum was filled with Gd-DTPA enriched ultrasound gel. First a T1/T2 weighted investigation of the pelvis was performed, followed by defecography with evacuation of the rectum. Images were obtained in a sagittal plane in a frequency of 1 image/second (true FISP) at rest and during straining. The obtained magnetic resonance imaging video tapes were analyzed off-line with cinematographic evaluation of bladder base, uterus, and anal canal position in relation to the pubococcygeal line by a blinded radiologist. Investigation time was 20 minutes. RESULTS: In dynamic magnetic resonance imaging defecography of the pelvic floor, 12 patients with descending perineum, 10 rectoceles (10 females), 6 cystoceles (6 females), 4 enteroceles (4 females), 8 intussusceptions (5 females), and a dyskinetic puborectalis muscle in 3 males were detected. In 11 females and 3 males multifocal disorders were found, involving more than one compartment in females, whereas in males complex defects were restricted to the posterior compartment. Magnetic resonance imaging defecography revealed diagnoses consistent with clinical results in 77.3 percent and defects in addition to clinical diagnoses in combined pelvic floor disorders in 34 percent. CONCLUSIONS: In complex pelvic floor disorders, involving more than a single defect, dynamic magnetic resonance imaging represents a convenient diagnostic procedure in females and to a lesser extent in males, in particular in terms of dynamic imaging of pelvic floor organs during defecation. In addition to the clinical assessment, dynamic magnetic resonance imaging had clinical impact in proctologic and interdisciplinary treatment.

Adult↗
PubMed2001

[Dynamic MR defecography for diagnosis of combined functional disorders of the pelvic floor in proctology].

PURPOSE: Evaluation of magnetic resonance defecography in the diagnosis of pelvic floor disorders were examined prospectively. MRI was performed on a 1.5 T scanner. The rectum was opacified with 200 ml of ultrasound transmission gel. A sagittal single section T2-weighted gradient echo sequence with a temporal resolution of 1.1 second was performed. Changes of the anorectal angle and the position of the pelvic organs in relation to the pubococcygeal line were registered at rest, during straining, and during evacuation of the rectum. RESULTS: Patients with obstructed defecation (n = 15) showed prolapse of the rectal mucosa (n = 5), anterior rectocele (n = 8), pelvic floor descent (n = 5), enterocele (n = 2), and anorectal dyscoordination (n = 3). Individuals with stool incontinence (n = 15) had an anterior rectocele (n = 10), pelvic floor descent (n = 11), enterocele (n = 2), prolapse of rectal mucosa (n = 1), and a puborectal insufficiency (n = 1). Urine incontinence was associated with cystocele (n = 10) or normal findings (n = 4). In patients with unspecific symptoms (n = 6), anorectal dyscoordination (n = 4) and prolapse of the rectal mucosa (n = 2) were found. MRI was superior for the detection of enteroceles, cystoceles and pelvic floor descent compared with clinical investigation. CONCLUSION: Dynamic MR imaging supplies complex information in anorectal disease and thus improves proctoscopy.

Adolescent↗
PubMed1999

Multiple hepatic angiolipomas: a case report and review of literature.

Follow-up of two hepatic angiolipomas in a patient without evidence of tuberous sclerosis is reported. Initially, the lesions presented as homogenously enhancing masses, which were nearly isodense to normal liver tissue on plain CT scans. Focal nodular hyperplasia was assumed. One year later, fat was detected in the growing tumors and percutaneous core biopsy revealed hepatic angiolipomas. Natural history of these rare lesions is unknown, and this is to the best of our knowledge the first observation of fatty metamorphosis in such a benign, mesenchymal hepatic neoplasm.

Adult↗
PubMed1997

[Computer tomography-guided gastrostomy, jejunostomy and gastrojejunostomy. A reliable non-surgical method also for contraindications and failure of percutaneous endoscopic gastrostomy].

OBJECTIVE: To analyse retrospectively the results of CT (computed tomography)-guided gastrostomy or gastroenterostomy where an endoscopic procedure was not possible or had failed. PATIENTS AND METHODS: Between August 1993 and March 1997, CT-guided gastrostomy (n = 50) or gastroenterostomy (n = 8) was performed in 58 patients (mean age 56 +/- 6 years; 51 males, 7 females). An endoscopic or fluoroscopic method had been contraindicated in 52 and had failed in 6 patients. RESULTS: Technical success was achieved in all patients. Three patients needed intravenous sedation. There were no procedure related complications requiring treatment. Three patients had a mild infection at the site of the skin puncture. CONCLUSION: CT-guided gastrostomy or gastroenterostomy is a safe and simple procedure which provides a minimally invasive alternative also in patients with contraindications to the established percutaneous method.

Adult↗