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J Link

Publications and source records attributed to J Link.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Volume-artifact reduction technique by spiral CT in the anterior, middle and posterior cranial fossae. Comparison with conventional cranial CT].

PURPOSE: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). METHODS: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. RESULTS: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosal bone, at the internal occipital crest, and at the level of the transverse sinus (p < 0.005). CONCLUSIONS: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae.

Adolescent↗
PubMed2000

[Therapy of iliac artery lesions with a new premounted balloon-expandable stent ("Flexible Iliac Bridge Stent")].

PURPOSE: Evaluation of the handling, technical success rate and six month patency rate of a new, premounted balloon-expandable stent in iliac artery lesions. MATERIALS AND METHODS: In a prospective study 26 stenoses and 3 occlusions of the iliac arteries were primary treated in 24 patients (Fontaine IIa-III, mean age 60.4 year) with the "Flexible Iliac Bridge Stent" (Medtronic AVE, Düsseldorf). Five patients had bilateral stenoses. The ankle-brachial index (ABI) in rest and after exercise was determined before the intervention as well as 1-3 days, 1 and 6 months after the Intervention. The handling and visibility of the stent was scored on a three grade scale by the operators. Follow-up angiography including intraarterial pressure measurement was performed in 17 out of 24 patients (21 out of 29 lesions) after 6 months. RESULTS: All 29 lesions were treated with technical success by implantation of 36 stents. The mean degree of the stenoses before intervention was 72.7 +/- 13.8% (+/- 1 standard deviation) and less than 5% in all cases postinterventionally. The mean pressure gradient before and after stent placement was 21 +/- 13.1 mm Hg and 0.8 +/- 2.3 mm Hg, respectively. The Fontaine stage improved by at least one in all patients. The mean ABI at rest improved from 0.63 +/- 0.15 to 0.89 +/- 0.16, and after exercise from 0.46 +/- 0.17 to 0.8 +/- 0.2, respectively. At 6 months 2 lesions out of 21 (9.5%) showed a restenosis of 55% and 70% with an intraarterial pressure gradient of 16 mm Hg and 27 mm Hg, respectively. After 6 months the mean ABI at rest decreased to 0.83 +/- 0.13, and to 0.72 +/- 0.14 after exercise. Handling and visibility was scored as good by all operators. CONCLUSION: Endoluminal therapy of iliac artery lesions with the used stent is safe and effective. The six month patency rate is comparable to the published data of other stents.

Adult↗
PubMed2000

[Contrast media-enhanced 3D MR angiography before endovascular treatment of aneurysm in the abdominal aorta, iliac artery and peripheral vessels].

PURPOSE: The value of DSA for the measurement of aortic and peripheral arterial aneurysm dimensions before endovascular treatment is limited by projection effects. It was evaluated if additional gadolinium-enhanced three-dimensional MR angiography (3D-CEMRA) could compensate for the disadvantages of DSA. MATERIALS AND METHODS: 21 patients with 35 aneurysms in the abdominal aorta (14), iliac (9) and femoropopliteal vessels (12) were assessed with DSA (7 with calibrated catheter, 14 with yardstick) and 3D-CEMRA (TR/TE 7.8/2.1 ms, flip-angle 40 degrees, Matrix 512 x 224, FOV 500 mm, eff. slice 1.8 mm). We measured and compared aneurysm dimensions on both modalities. 3D-CEMRA was regarded as the reference method to evaluate the dimension of DSA-projection effects. RESULTS: Diameter and length of aneurysms were underestimated on DSA with the yardstick as reference. The deviation ranged from 15% (+/- 5%) in the aorta to 21% (+/- 10%) in the iliac vessels. Only with calibrated catheters as reference (7/21 DSA), were the distances on DSA correlated well with MRA. In 2/35 aneurysms 3D-CEMRA detected thrombosis with difference between length of inner lumen dilatation on DSA and whole aneurysm length. 2/5 accessory renal arteries found on DSA were not detected on 3D-CEMRA. CONCLUSIONS: 3D-CEMRA is a valuable adjunct to DSA for pre-interventional diagnostics of aortic and peripheral arterial aneurysms. It provides exact evaluation of aneurysm dimensions and information about partial thrombosis.

Aneurysm↗
PubMed2000

[Contrast media-enhanced MR angiography of the lower extremity arteries using a dedicated peripheral vascular coil system. First clinical results].

PURPOSE: To evaluate contrast enhanced magnetic resonance angiography (ceMRA) of the pelvic and peripheral arteries with a dedicated peripheral vascular coil system and automated table-feed technique in patients with arterial occlusive disease. METHODS: Three-dimensional gadolinium-enhanced MR angiography in a two-step automatic table feed technique was performed in 45 patients using a 1.5 Tesla imager (Magnetom Symphony, Siemens). The pelvic arteries were imaged with a single injection of contrast material. The upper and the lower leg were imaged with a second injection of contrast material in an automated table feed technique using a dedicated vascular coil system. In 20 patients ceMRA was compared with digital subtraction angiography (DSA) as the standard of reference and in 25 patients ceMRA was performed solely. RESULTS: Sensitivity and specificity for grading significant stenoses > or = 50% and occlusions (in parenthesis) were in the pelvic arteries 94.7%, 96.8%, (100%, 100%), in the arteries of the upper leg 92.3%, 93.3% (87.5%, 100%) and in the arteries of the lower leg 96.5%, 95.8%, (95.2%, 96.8%), respectively. Depiction of the runoff vessels of the lower leg was excellent in ceMRA. CeMRA was of diagnostic quality in all the patients. CONCLUSION: Contrast-enhanced MRA using a dedicated peripheral vascular coil system increases the diagnostic quality of the lower leg. The runoff vessels can be evaluated. Thus, ceMRA in the presented technique is a diagnostic alternative to arterial angiography.

Adult↗
PubMed2000

Magnetic resonance monitoring of stent deployment: in vitro evaluation of different stent designs and stent delivery systems.

RATIONALE AND OBJECTIVES: To evaluate MR imaging features of commercially available stents before, during, and after in vitro deployment as a step toward MR-guided stent deployment. METHODS: Fourteen stents were deployed in a phantom under MR monitoring at 1.5 T by using a gradient-echo sequence. Device visibility was rated on a four-point scale (excellent, fair, poor, not visible). RESULTS: The Memotherm stent and the rolling membrane (RM) Wallstent showed excellent stent visibility and at least fair scores for artifact-induced narrowing of the stent lumen. Three stents (Palmaz, AVE, Easy Wallstent) showed excellent visibility of the stent but no visible lumen. Five stents (Strecker, Accuflex, Hemobahn, Passager, Sinus) displayed fair visibility. The delivery catheters of four stent systems (Smart, Vascucoil, Symphony, ZA) displayed severe black hole artifacts. CONCLUSIONS: The imaging features of several stent systems might be suitable for MR-guided intervention. The Memotherm and the Wallstent RM combine good visibility of the stent and the lumen.

Blood Vessel Prosthesis↗
PubMed2000

Chest radiography with a large-area detector based on cesium-iodide/amorphous-silicon technology: image quality and dose requirement in comparison with an asymmetric screen-film system.

The purpose of this study was to evaluate a large-area, flat-panel X-ray detector, which uses cesium-iodide (CsI) and amorphous silicon (a-Si). Conventional images were compared with digital images acquired with equal dose (2.5 microGy) and with 50% dose reduction. Fifteen consecutive patients were studied prospectively using an asymmetric screen-film system (detector dose, 2.5 microGy). Digital images were taken from the same patients in a posteroanterior view with detector doses of 2.5 and 1.25 microGy, respectively. The CsI/a-Si active-matrix imager had a panel-size of 43 x 43 cm, a matrix of 3 x 3k, and a pixel-pitch of 143 microm. Hard copies were presented in a random order to eight independent observers, who rated image quality according to six subjective quality criteria. Statistical significance of differences was evaluated with Student's t test for paired samples (confidence level, 95%). Digital radiographs with 2.5 and 1.25 microGy were superior to conventional images regarding all quality criteria. Statistically significant differences were observed for five of six criteria at a detector dose of 2.5 microGy and for only one quality feature at 1.25 microGy. Flat-panel digital imagers based on CsI/a-Si technique have the potential to replace conventional systems and might allow a reduction of radiation dose by 50% without loss of image quality.

Adult↗
PubMed2000

Stent appearance at contrast-enhanced MR angiography: in vitro examination with 14 stents.

PURPOSE: To evaluate signal intensity changes influencing assessment of stent patency at contrast material-enhanced magnetic resonance (MR) angiography. MATERIALS AND METHODS: By using an in vitro model, 14 stents-nine nitinol, one tantalum, two stainless steel, and two cobalt alloy-were investigated regarding their appearance at MR imaging. A vascular phantom consisting of tubes filled with 2.00 mmol/L gadopentetate dimeglumine in saline solution was studied in different orientations within the magnetic field. Imaging was performed with a fast three-dimensional gradient-echo sequence (4. 70/1.89 [repetition time msec/echo time msec]). Relative signal intensity reduction within the stents and the degree of artificial narrowing of the stent lumen were calculated. RESULTS: The stent lumen was visible within 13 stents. A total signal void inside the stent lumen appeared in only one cobalt alloy stent. Artificial narrowing of the diameter was less than 33% in 10 of 14 stents. The tantalum stent and four nitinol stents seemed best suited for contrast-enhanced MR angiography. A bandlike artifact occurred at the ends of the stents when positioned along the readout direction. CONCLUSION: To differentiate between artifacts and stenoses, knowledge of the degree of signal intensity reduction and artificial lumen narrowing within vascular stents is essential. Stent geometry, relative orientation to the magnetic field, and alloy composition influence signal intensity alteration within the stent lumen.

Contrast Media↗
PubMed2000

Time-resolved contrast-enhanced MR angiography of renal artery stenosis: diagnostic accuracy and interobserver variability.

OBJECTIVE: The purpose of this study was to evaluate diagnostic accuracy and interobserver variability of time-resolved three-dimensional gadolinium-enhanced MR angiography in the detection of renal artery stenosis in comparison with intraarterial digital subtraction angiography as the standard of reference. SUBJECTS AND METHODS: Forty consecutive patients (age range, 25-81 years; mean, 62.9 +/- 11.9 years) with suspected renal artery stenosis underwent intraarterial digital subtraction angiography and gadolinium-enhanced MR angiography, performed on a 1.5-T system with fast low-angle shot three-dimensional imaging (3.8/1.49 [TR/TE], 25 degrees flip angle, 10-sec acquisition time, and 1.5-mm partition thickness). Three time-resolved phases were obtained in a single breath-hold. Digital subtraction angiography and gadolinium-enhanced MR angiography were evaluated by four observers who studied 80 main renal arteries and 19 accessory vessels to evaluate the degree of stenosis. A stenosis reducing the intraarterial diameter by more than 50% was regarded as hemodynamically significant. Interobserver variability was calculated. RESULTS: Only one gadolinium-enhanced MR angiography study was not of diagnostic quality, as a result of failure of the power injector. All main branches were of diagnostic quality in 38 (97.4%) of the remaining 39 gadolinium-enhanced MR angiography studies. Seventeen (89.5%) of 19 accessory renal arteries were depicted with gadolinium-enhanced MR angiography. The overall sensitivity for significant stenoses was 92.9%. The overall specificity was 83.4%, and the overall accuracy was 85.9%. Interobserver variability of gadolinium-enhanced MR angiography exceeded that of digital subtraction angiography. CONCLUSION: Time-resolved three-dimensional gadolinium-enhanced MR angiography is a useful noninvasive method of screening suspected renal artery stenosis because of its easy application, short examination time, and high sensitivity despite of its higher interobserver variability.

Adult↗
PubMed1999

A phase I study of a HER2/neu bispecific antibody with granulocyte-colony-stimulating factor in patients with metastatic breast cancer that overexpresses HER2/neu.

A phase I study of escalating doses of humanized bispecific antibody (bsAb) MDX-H210 with granulocyte-colony-stimulating factor (G-CSF) was conducted in patients with metastatic breast cancer that overexpressed HER2/neu. The main objectives of the study were to define the maximal tolerated dose (MTD) of MDX-H210 when combined with G-CSF, to measure the pharmacokinetics of MDX-H210 when administered with G-CSF, and to determine the toxicity, biological effects and possible therapeutic effect of MDX-H210 with G-CSF. MDX-H210 is a F(ab)' x F(ab)' humanized bispecific murine antibody that binds to both HER2/neu and the FcgammaR1 receptor (CD64), and was administered intravenously weekly for three doses followed by a 2-week break and then three more weekly doses. A total of 23 patients were treated, and doses were escalated from 1 mg/m2 to 40 mg/m2 with no MTD reached. The toxicity of the bsAb + G-CSF combination was modest, with no dose-limiting toxicity noted: 19 patients had fevers, 7 patients had diarrhea, and 3 patients had allergic reactions that did not limit therapy. The beta-elimination half-life varied from 4 h to 8 h at doses up to 20 mg/m2. Significant release of cytokines interleukin-6, G-CSF, and tumor necrosis factor alpha was observed after administration of bsAb. Circulating monocytes disappeared within 1 h of bsAb infusion, which correlated with binding of bsAb, noted by flow-cytometric analysis. Significant levels of human anti-(bispecific antibody) were measured in the plasma of most patients by the third infusion. No objective clinical responses were seen in this group of heavily pre-treated patients.

Adult↗
PubMed1999

[Rotational digital subtraction angiography of carotid bifurcation stenosis].

PURPOSE: A prospective study was designed to evaluate, whether multiplanar imaging with rotational digital subtraction angiography (R-DSA) could improve assessment of carotid artery bifurcation stenosis. PATIENTS AND METHODS: 45 patients with suspected stenosis of the ICA were examined with DSA in standard projections (0 degree-(45 degrees)-90 degrees) and additional R-DSA of each ICA from 0-90 degrees in 10 degrees steps. We compared imaging quality and degree of stenosis as well as exposure of the patients to radiation and contrast media. RESULTS: 79/82 R-DSA (96%) were suitable for evaluation of stenosis, 58/82 (70%) matched the quality standard of single projection DSA. Specificity and sensitivity of the R-DSA to diagnose high grade ACI stenosis were 100% and 94%, respectively. 7/79 R-DSA revealed a higher and 3/79 a lower degree of stenosis than the corresponding DSA. Regarding the degree of stenosis there was no significant difference between the two modalities (p > 0.05), but R-DSA detected 4 stenoses greater than 60% that were estimated to be lower than 60% by DSA. Radiation dose for R-DSA was equivalent to one DSA run (170 cGycm2). The average amount of contrast media (25 ml) was slightly higher than for 2-3 single-projection DSA (19.8 ml). CONCLUSIONS: R-DSA provides high quality imaging of the carotid bifurcation with multiplanar projections facilitating exact grading of vessel stenosis. The number of cases (n = 2) is to small to judge the value of R-DSA as to (tandem-) stenosis of the distal ICA. Still, diagnostic value and low radiation exposure justify the use of R-DSA as additional series to standard protocols.

Adult↗
PubMed1999

[Contrast medium-enhanced MR angiography of the pelvic and leg vessels with an automated table-feed technique].

PURPOSE: To evaluate contrast enhanced magnetic resonance angiography (ceMRA) with an automated table-feed technique in patients with arterio-occlusive disease for imaging of the pelvic and peripheral arteries. METHODS: Twenty-two patients underwent three-dimensional gadolinium-enhanced MR angiography in a three-step automatic table-feed technique on a Magnetom Symphony operating at 1.5 Tesla. Maximum intensity projection images (MIP) were generated from the subtracted and original studies. Image quality and venous contrast were evaluated by two groups of observers. 304 vessels (17 patients) were compared with DSA as the standard of reference. RESULTS: All examinations were performed without any technical problems. Diagnostic quality of the MIP of subtracted data sets was superior to that of the unsubtracted images. Venous overlay was 61% in the lower leg. In a total of 599 observations, a sensitivity of 96% (95%, 82%) and a specificity of 87% (88%, 99%) were high compared to DSA in the detection of significant stenoses > or = 50% (> or = 75%, occlusions). Interobserver correlation was good (linear correlation 0.9). CONCLUSION: Stepping-table digital subtraction contrast enhanced MRA is a promising technique in the diagnosis of peripheral arterio-occlusive disease.

Aged↗
PubMed1999

[Digital 3D rotational angiography for the preoperative and preinterventional clarification of cerebral arterial aneurysms].

OBJECTIVE: Does the recently introduced 3D angiography provide additional information beyond standard angiography (DSA) for the diagnosis of cerebral aneurysms? METHODS: During a 3-months period DSA and 3D-angiography were performed in 40 patients harbouring a total of 49 aneurysms. Vascular regions that presented an aneurysm diagnosed by DSA were reevaluated by 3D-angiography. RESULTS: In two patients, vessel-loops previously described as aneurysms by DSA could be identified by 3D-angiography. In one patient, an aneurysm was diagnosed that could not be detected by DSA. In another case, the definitive diagnosis of an aneurysm was obtained only with 3D-angiography. In one patient, an aneurysm was diagnosed that could not be detected by DSA. In another case, the diagnosis of an aneurysm was obtained only with 3D-angiography. In two cases, aneurysms could be definitively excluded by 3D-angiography, whereas in another aneurysm a vessel originating from this lesion was identified. The size of the aneurysms measured by both methods was identical. CONCLUSIONS: Multiple projections of 3D-angiography provide a better evaluation of the anatomic situation regarding the base of the aneurysm as well as the relationship of an aneurysm to neighbouring vessels. Further, an exact differentiation between a vessel loop and an aneurysm can be made. Therefore, 3D-angiography is a valuable tool when used in conjunction with DSA.

Adult↗
PubMed1999

Iliofemoral arterial occlusive disease: contrast-enhanced MR angiography for preinterventional evaluation and follow-up after stent placement.

PURPOSE: To evaluate the efficacy of contrast material-enhanced magnetic resonance (MR) angiography for the diagnosis of peripheral arterial occlusion and follow-up after stent placement. MATERIALS AND METHODS: Sixty-seven patients (21 women, 46 men; mean age, 64.6 years) were examined. Digital subtraction angiography and contrast-enhanced MR angiography were performed in 28 patients for preinterventional evaluation of iliofemoral arterial occlusion and in 39 patients for follow-up after stent placement in the iliac or femoral arteries, which had been performed several months before. RESULTS: All 24 occlusions were correctly diagnosed with contrast-enhanced MR angiography. Of the 59 stenoses, 36 were greater than 50% and 23 were 50% or less. Sensitivity and specificity for the detection of stenoses greater than 50% were 100% and 83%, respectively. Patency of the different stents was determined correctly with contrast-enhanced MR angiography. Some stents caused signal intensity dropout, which made MR evaluation of stents difficult. Generally, these signal intensity artifacts were most severe in stainless steel stents and mild in some nitinol stents. CONCLUSION: Contrast-enhanced MR angiography is comparable to digital subtraction angiography for the detection of stenosis greater than 50% and occlusion in the iliofemoral arteries. Stent patency can be determined, but contrast-enhanced MR angiography is not suitable for stent evaluation owing to signal intensity dropout; however, it provides information about the vascular anatomic areas proximal and distal to the stent.

Angiography, Digital Subtraction↗
PubMed1998

[Contrast-enhanced MR angiography in Leriche's syndrome].

PURPOSE: To determine the usefulness of contrast-enhanced MR angiography for the diagnosis of Leriche's syndrome. MATERIAL AND METHODS: Leriche's syndrome was seen in 7 patients via DSA. In addition, contrast-enhanced MR angiography was performed (TR 7.8 ms/TE 2.1 ms, flip angle 30 degrees, slab thickness 116 mm, slice thickness 1.82 mm, 64 partitions, FOV 500 x 438 mm, matrix 224 x 512). RESULTS: Diagnosis of Leriche's syndrome was possible by contrast-enhanced MR angiography in each case. Visualisation of the femoral arteries was not possible in two patients by intraarterial DSA, in three other patients there was an insufficient contrast in the femoral arteries with DSA. Contrast-enhanced MR angiography revealed good visualisation of the femoral arteries in these patients. In addition, contrast-enhanced MR angiography allowed complete visualisation of the patent lower limb arteries. In intraarterial DSA visualisation of the lower limb arteries was achieved reached in only one patient, but was incomplete. CONCLUSION: Contrast-enhanced MR angiography yielded the correct diagnosis of Leriche's syndrome in all 7 patients. Contrast-enhanced MR angiography was superior to DSA in the assessment of the distal run-off vessels in five of seven patients.

Adult↗
PubMed1998

[Treatment of arterial femoropopliteal obstructions with Palmaz midsize stents].

PURPOSE: To evaluate effectiveness, success and patency rates after endovascular treatment with mid-size Palmaz stents in high-grade stenoses or short-distance occlusions of femoral arteries. MATERIALS AND METHODS: 27 patients with 10 occlusions (average length 3.2 +/- 1.4 cm) and 17 severe stenoses of the superficial femoral artery were treated with 33 mid-size Palmaz stents. The follow-up included Doppler ultrasound at one, three, 6 and 12 months and an angiography at 6 months. Mean follow-up was 6.5 months. RESULTS: Technical success was 100%. The ankle-brachial index improved from 0.57 +/- 0.28 pretreatment to 0.87 +/- 0.13 within 24 hours. Acute stent thrombosis occurred in two patients (< 3 weeks). Angiography at 6 months revealed restenosis rates of 7.4% (> 50%, n = 2). Life-table analysis according to Kaplan-Meier revealed 6-month primary and secondary patency rates of 84% and 91%. CONCLUSION: With regard to our limited data, the implantation of mid-size Palmaz stents in femoral arteries seems promising in treatment of short-distance occlusions and stenoses of the femoral artery.

Aged↗
PubMed1998

MRI features of craniofacial fibrous dysplasia.

A 13-year-old female with a 4-year history of monostotic fibrous dysplasia had noticed a progressive proptosis of the right eye and diplopia on upward gaze for 4 weeks. A few years previously an incisional biopsy of the skull had verified the presumed diagnosis of fibrous dysplasia with recurrent bleeding into pathologic cystic bony structures of the skull. The patient was known to have craniofacial fibrous dysplasia with involvement of the frontal and intermediate cranial base, the posterior ethmoidal labyrinth, and the sphenoidal and maxillary sinuses. Eye examination showed a reduced visual acuity in the right eye without defects of the visual field. MR imaging showed a fluid-filled cystic cavity in the orbital frontal bone pushing the globe downwards. Four months later she developed similar symptoms on the other side while proptosis of the right eye was regressive. T2-weighted MRI revealed a large fluid-filled cystic cavity with a fluid-fluid level in the upper part of the left orbit. It is concluded that follow-up studies can be easily performed by MRI without additional exposure to radiation. The total extent of osseous involvement can be determined. Thus, MRI may be helpful in deciding between operative or conservative therapy.

Journal Article↗