nitinol and iopromide

To compare the value of inversion recovery with on-resonant water suppression (IRON) to conventional T1-weighted (T1w) MRA and computed tomography angiography (CTA) for visualization of peripheral nitinol stents. We visualized 14 different peripheral nitinol stents in vitro both using Gadolinium (Gd) and ultrasmall superparamagnetic iron nanoparticles (USPIOs) for conventional T1w and IRON-MRA using clinical grade 1.5T MR scanner and iodinated contrast material for CTA using a 256-slice CT scanner. Parameter assessment included signal- and contrast-to-noise ratio (S/CNR), relative in-stent signal and artificial lumen narrowing. X-ray angiography served as gold standard for diameter assessment. Gd-enhanced IRON-MRA exhibited highest in-stent SNR and CNR values compared to conventional T1w MRA (IRON (Gd/USPIO): SNR = 30 ± 3/21 ± 2, CNR = 23 ± 2/14 ± 1; T1w: SNR = 16 ± 1/14 ± 2, CNR = 12 ± 1/10 ± 1, all p < 0.05). Furthermore, IRON-MRA achieved highest relative in-stent signal both using Gd and USPIO (IRON (Gd/USPIO): 121 ± 8 %/103 ± 6 %; T1w: 73 ± 2 %/66 ± 4 %; CTA: 84 ± 6 %, all p < 0.05). However, artificial lumen narrowing appeared similar in all imaging protocols (IRON (Gd/USPIO): 21 ± 3 %/21 ± 2 %; T1w: 16 ± 4 %/17 ± 3 %; CTA: 19 ± 2 %, all p = NS). Finally, IRON-MRA provided improvement of the in-stent lumen visualization with an 'open-close-open' design, which revealed a complete in-stent signal loss in T1w MRA. IRON-MRA improves in-stent visualization in vitro compared to conventional T1w MRA and CTA. In light of the in vitro results with Gd-enhanced IRON-MRA, the clinical implementation of such an approach appears promising.

Topics: Alloys; Artifacts; Blood Vessels; Computed Tomography Angiography; Contrast Media; Dextrans; Gadolinium DTPA; Iohexol; Magnetic Resonance Angiography; Magnetite Nanoparticles; Models, Anatomic; Models, Cardiovascular; Multidetector Computed Tomography; Observer Variation; Predictive Value of Tests; Prosthesis Design; Reproducibility of Results; Stents

To evaluate the clinical efficacy and safety of radiologic management for the treatment of benign tracheal strictures caused by tracheostomy.. We retrospectively reviewed of 13 patients with benign tracheal stricture caused by tracheostomy that was treated with balloon dilation or stent placement. Balloon dilation had initially been performed. Stent placement was indicated in patients who showed a poor response to balloon dilation. Outcomes were assessed according to the following variables: technical and clinical success, Hugh-Jones classification scale before and after the procedures, and complications.. Balloon dilation and stent placement were technically successful in all patients. Nine of the 13 patients (69 %) showed no response to balloon dilation, and the remaining the four patients showed a positive response to initial balloon dilation. Six of the nine (67 %) patients showed a good response to temporary stent placement and required no further treatment. Mean Hugh-Jones grades improved from 3.6 ± 0.8 to 1.8 ± 1.1 (P < 0.001). During a follow-up period of 2.6-40.8 months (mean 16.5), overall clinical success was achieved in 10 patients (77 %) after a single balloon dilation (n = 4) and temporary stent placement (n = 6). The remaining three patients with clinical failure underwent tracheal resection (n = 3).. Radiologic management can be a safe and effective therapeutic option for treating benign tracheal stricture caused by tracheostomy. Temporary stent placement can be effective in patients with symptoms recurring soon after balloon dilation.

Topics: Adolescent; Adult; Aged; Alloys; Bronchoscopy; Contrast Media; Female; Fluoroscopy; Humans; Iohexol; Male; Middle Aged; Radiography, Interventional; Retrospective Studies; Stents; Tomography, X-Ray Computed; Tracheal Stenosis; Tracheostomy

To evaluate the technical success and initial clinical safety and effectiveness of the use of a Y-shaped metallic stent for complex stenoses involving the carina.. Thirty-five consecutive patients with complex tracheobronchial stenoses involving the carina were treated with an integrated self-expandable inverted Y-shaped metallic stent and delivery system. The Y-shaped metallic stents were placed in the tracheobronchial tree with fluoroscopic guidance. Technical success, clinical success, Hugh-Jones classification, and complications were assessed during follow-up.. The delivery of the integrated self-expandable Y-shaped metallic stent in the carinal areas was technically successful and well-tolerated in all patients. Clinical success was achieved in 31 patients (89%) 1-7 days after stent placement; the procedure failed in four patients (11%). The improvement between pre- and postoperative Hugh-Jones classification grade was statistically significant (P<.001). During follow-up (mean follow-up, 192 days+/-169), all stenoses were resolved, and general physical examination of the 31 patents showed improvement with no obvious dyspnea or bleeding. Twenty-one patients were healthy without evidence of dyspnea, and the remaining 14 patients died (mean survival, 189 days+/-172) at the time of this report. The mean and median survival periods were 217 days+/-30 and 215 days+/-108, respectively. The mean and median stent patency periods were 216 days+/-30 and 215 days+/-119, respectively.. Deployment of an integrated, self-expandable inverted Y-shaped metallic stent with the delivery system was a safe and effective procedure for the treatment of complex tracheobronchial stenoses involving the carina.

Topics: Aged; Aged, 80 and over; Alloys; Bronchial Diseases; Constriction, Pathologic; Contrast Media; Female; Fluoroscopy; Humans; Iohexol; Male; Middle Aged; Prosthesis Design; Radiography, Interventional; Stents; Tracheal Stenosis; Treatment Outcome

The objective of this study was to compare contrast-enhanced magnetic resonance angiography (CE MRA) and multislice computed tomographic angiography (MS CTA) in the follow-up of thoracic stent-graft placement. The CE MRA and MS CTA were performed following nitinol stent-graft treatment due to thoracic aneurysm ( n=4), intramural bleeding ( n=2) and type-B aortic dissection ( n=5). Corresponding evaluation of arterial-phase imaging characteristics focused on the stent-graft morphology and leakage assessment. Stent-graft and aneurysm extensions were comparable between both techniques. Complete exclusion (aneurysm, n=4; dissection, n=2) was assessed with high confidence with CE MRA and MS CTA. Incomplete exclusion (intramural bleeding, n=2; dissection, n=3) was assigned to lower confidence scores on CE MRA compared with MS CTA. On CE MRA the stent-graft lumen demonstrated an inhomogeneous signal, the stent struts could not be assessed. The CE MRA can be used as alternative non-invasive imaging for follow-up of nitinol stent grafts. Arterial-phase leak assessment can be less evident in CE MRA compared with MS CTA studies; therefore, the use of late-phase imaging seems to be necessary. The diagnostic gap of stent-graft fracture evaluation using MRA may be filled with plain radiographs.

Topics: Aged; Alloys; Angiography; Aortic Aneurysm, Thoracic; Aortic Dissection; Blood Vessel Prosthesis Implantation; Contrast Media; Female; Follow-Up Studies; Gadolinium; Humans; Imaging, Three-Dimensional; Iohexol; Magnetic Resonance Angiography; Male; Organometallic Compounds; Stents; Tomography, X-Ray Computed

To determine the technical feasibility and clinical outcome of juxtarenal placement of covered stent-grafts for endovascular treatment of abdominal aortic aneurysms with a proximal neck less than 15 mm long.. In seven patients, abdominal aortic aneurysms with infrarenal necks 3-14 mm long were excluded with juxtarenal implantation of polyester-nitinol coknit stent-grafts. The proximal uncovered portion of the stent-graft (length, 12 mm) was placed across one or both orifices of the renal arteries. Seven patients underwent standard infrarenal stent-graft placement. Clinical outcome in all 14 patients was determined with computed tomography (CT) and laboratory values and also with captopril renography in the patients who underwent juxtarenal placement. The mean follow-up was 10.1 months.. Findings from serial follow-up CT and laboratory analysis performed in all patients and captopril renography performed in five of the patients who underwent juxtarenal stent-graft placement did not reveal impaired renal function or perfusion.. Successful exclusion of abdominal aortic aneurysms located closer than 15 mm to the orifices of the renal arteries is possible with juxtarenal placement of the uncovered portion of the stent in the abdominal portion of the aorta.

Topics: Aged; Alloys; Angiography, Digital Subtraction; Aortic Aneurysm, Abdominal; Blood Vessel Prosthesis Implantation; Contrast Media; Feasibility Studies; Female; Follow-Up Studies; Humans; Iohexol; Male; Polyesters; Prosthesis Design; Radioisotope Renography; Renal Artery; Stents; Time Factors; Tomography, X-Ray Computed; Treatment Outcome