REDCap on FHIR: Clinical Data Interoperability Services.

BACKGROUND: Despite widespread use of electronic data capture (EDC) systems for research and electronic health records (EHR), most transfer of data between EHR and EDC systems is manual and error prone. Increased adoption of Health Level Seven Fast Healthcare Interoperability Resource (FHIR) application programming interfaces (APIs) in recent years by EHR systems has increased the availability of patient data for external applications such as REDCap. OBJECTIVE: Describe the development of the REDCap Clinical Data Interoperability Services (CDIS) module that provides seamless data exchange between the REDCap research EDC and any EHR system with a FHIR API. CDIS enables end users to independently set up their data collection projects, map EHR data to fields, and adjudicate data transfer without project-by-project involvement from Health Information Technology staff. METHODS: We identified two use cases for EHR data transfer into REDCap. Clinical Data Pull (CDP) automatically pulls EHR data into user-defined REDCap fields and replaces the workflow of having to transcribe or copy and paste data from the EHR. Clinical Data Mart (CDM) collects all specified data for a patient over a given time period and replaces the process of importing EHR data for registries from research databases. With an iterative process, we designed our access control, authentication, variable selection, and mapping interfaces in such a way that end users could easily set up and use CDIS. RESULTS: Since its release, the REDCap CDIS has been used to pull over 19.5 million data points for 82 projects at Vanderbilt University Medical Center. Software and documentation are available through the REDCap Consortium. CONCLUSIONS: The new REDCap Clinical Data and Interoperability Services (CDIS) module leverages the FHIR standard to enable real-time and direct data extraction from the EHR. Researchers can self-service the mapping and adjudication of EHR data into REDCap. The uptake of CDIS at VUMC and other REDCap consortium sites is improving the accuracy and efficiency of EHR data collection by reducing the need for manual transcription and flat file uploads.

A Pilot Study of Femoropopliteal Artery Revascularisation with a Low Dose Paclitaxel Coated Balloon: Is Predilatation Necessary?

OBJECTIVE/BACKGROUND: The objective was to compare 2 year outcomes in patients treated with or without predilatation prior to drug coated balloon (DCB) angioplasty for symptomatic femoropopliteal lesions. METHODS: This prospective multicentre pilot study was conducted at three sites in Germany. It compared claudicants undergoing predilatation with a bare percutaneous transluminal angioplasty (PTA) balloon before DCB (predilatation group) with patients undergoing direct DCB (direct DCB group). Patients were followed for 2 years. Outcomes included late lumen loss at 6 months, and ankle brachial index (ABI), major adverse events, and primary patency at 2 years. A Clinical Events Committee and core laboratories analysed adverse events and angiographic/duplex images, respectively. RESULTS: Between December 2011 and November 2012, 50 patients were enrolled to the predilatation group (12% total occlusions) and 28 to the direct DCB group (5% total occlusions). Follow-up compliance at the 2 year visit was 88% (n = 44) and 86% (n = 24), respectively. Late lumen loss at 6 months was lower in the direct DCB group (0.03 ± 0.68 mm vs. 0.54 ± 0.97 mm; p = .01). Major adverse events over 2 years occurred in seven (15%) patients who underwent predilatation and in five (19%) after direct DCB. Mean ABI at 2 years was 0.94 ± 0.15 after predilatation and 1.0 ± 0.12 after direct DCB. Over 2 years, primary patency (80.3% vs. 78.2%; p = .55) was not statistically different between the groups. After propensity score adjustments, 2 year findings remained unchanged. CONCLUSION: Paclitaxel coated PTA, with or without bare predilatation, is effective over 2 years in symptomatic patients with femoropopliteal stenotic lesions. Adequately powered randomised controlled comparisons are required to confirm these preliminary results.

[Comparison of regional distribution of cancellous bone in osteoporotic and non-osteoporotic distal radii]. / Vergleich der lokalen Spongiosadichte osteoporotischer und nichtosteoporotischer distaler Radii.

BACKGROUND: In cases of distal radius fractures information about the regional distribution of cancellous bone is essential for adequate fixation of osteosynthesis material. MATERIALS AND METHODS: Using quantitative computed tomography (qCT) measurements 12 distal radii were divided into 2 groups (good and bad bone quality). High-resolution CT scans were obtained at 13 locations (1-40 mm distant from radial styloid processes). The resulting cross-sections were divided into 4 quadrants and the cancellous bone density was assessed in each of them. RESULTS: In both groups regional cancellous bone density was highest immediately beneath the joint surface and decreased towards the metaphyseal region. Comparing the radial with the ulnar quadrants significant differences were found between distances of 4 mm and 12 mm from the joint surface in both groups. The comparison of the palmar and the dorsal quadrants resulted in an almost identical cancellous bone distribution. CONCLUSION: In osteoporotic distal radii cancellous bone density decrease occurs homogeneously in all regions and is least pronounced beneath the joint surface. Comparing the regional cancellous bone density (radial versus ulnar and palmar versus dorsal) significant differences were mainly found near the joint surface in both groups.

HIV-related tuberculosis: mortality risk in persons without vs. with culture-confirmed disease.

BACKGROUND: Tuberculosis (TB) diagnosis in human immunodeficiency virus (HIV) positive persons is difficult, particularly in resource-limited settings. The relationship between TB culture status and mortality in HIV-positive persons treated for TB is unclear. METHODS: We evaluated HIV-positive adults treated for TB at or after their first HIV clinic visit in Argentina, Brazil, Chile, Honduras, Mexico or Peru from 2000 to 2015. Anti-tuberculosis treatment included 2 months of isoniazid, rifampicin (RMP)/rifabutin (RBT), pyrazinamide ± ethambutol, followed by continuation phase treatment with isoniazid + RMP/RBT. RESULTS: Of 759 TB-HIV patients, 238 (31%) were culture-negative, 228 (30%) had unknown culture status or did not undergo culture and 293 (39%) were culture-positive. The median CD4 at TB diagnosis was 96 (interquartile range 40-228); 636 (84%) received concurrent antiretroviral therapy (ART) and anti-tuberculosis treatment. There were 123 (16%) deaths: 90/466 (19%) with TB culture-negative, unknown or not performed vs. 33/293 (11%) who were TB culture-positive (P = 0.005). In Kaplan-Meier analysis, mortality in TB patients without culture-confirmed disease was higher (P = 0.002). In a Cox model adjusted for age, sex, CD4, ART timing, disease site and stratified by study site, mortality in persons without culture-confirmed TB was not significantly increased compared to those with culture-positive TB (hazard ratio 1.39, 95%CI 0.89-2.16, P = 0.15). CONCLUSION: Most HIV-positive patients treated for TB did not have culture-confirmed TB, and mortality tended to be higher in patients without culture-confirmed disease, although the association was not statistically different after adjusting for other variables. Accurate TB diagnosis in HIV-positive persons is crucial.

Prophylaxis of restenosis with (186)re-labeled stents in a rabbit model.

BACKGROUND: Intraluminal beta-irradiation has been shown to decrease neointimal proliferation after angioplasty in experimental models. The purpose of this study was to test the technical feasibility and biological effects of (186)Re-labeled stents. METHODS AND RESULTS: Thirty-four New Zealand White rabbits were fed a 0.5% cholesterol diet before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were killed 7 weeks after stent implantation. Two of 34 animals died prematurely (aortic leak, pneumonia). Control stents (n=7) were compared with (186)Re stents (2.6 MBq [n=6], 8.1 MBq [n=5], 16.0 MBq [n=6], and 25.3 MBq [n=8]). Stent application was successful in all cases. No thrombus occlusion was observed. After 7 weeks, neointima formation was 2.2+/-0.2 mm(2) in the control group. In the treatment groups, a dose-dependent neointima reduction was detectable (0.5+/-0.5 mm(2) [2.6 MBq], 0.4+/-0.4 mm(2) [8.1 MBq], and 0 mm(2) [16.0 MBq, 25.3 MBq]). No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed reendothelialization. CONCLUSIONS: (186)Re stents were capable of reducing neointima formation in a dose-dependent fashion. (186)Re stents did not cause late thrombosis or neointimal induction at the stent margins in the observation period of 7 weeks.

Massive pulmonary embolism: percutaneous emergency treatment by pigtail rotation catheter.

OBJECTIVES: This study was designed to assess the feasibility, efficacy and safety of mechanical fragmentation of pulmonary emboli using a new rotational pigtail catheter system. BACKGROUND: Acute massive pulmonary embolism associated with right ventricular dysfunction is frequently lethal, despite high-dose thrombolytic therapy. Adjunctive catheter fragmentation may prevent a fatal outcome. METHODS: In 20 patients (age 58.9+/-10.5 years) with severe hemodynamic impairment, massive pulmonary emboli were fragmented by mechanical action of the rotating pigtail. Fifteen patients received thrombolysis after embolus fragmentation or no thrombolysis at all (noninterference group). RESULTS: Prefragmentation pulmonary arterial occlusion was 68.6 +/- 11.3% for both lungs. Pulmonary placement and navigation of the fragmentation catheter was easy and rapid. Fragmentation time was 17+/-8 min. The noninterference group showed a decrease pre- to postfragmentation of shock index from 1.28+/-0.53 to 0.95+/-0.38 (p = 0.011), mean pulmonary artery pressure from 31+/-5.7 to 28+/-7.5 mm Hg (p = 0.02) and a recanalization by fragmentation of 32.9+/-11.8% (mean angiographic score per treated lung from 7.4 to 5.0). Overall mortality was 20%. CONCLUSIONS: Fragmentation by pigtail rotation catheter provided for a rapid and safe improvement of the hemodynamic situation and an average recanalization of about one-third of the pulmonary embolic occlusion. The method appears useful especially in high-risk patients threatened by right ventricular failure, to accelerate thrombolysis, and as a minimal-invasive alternative to surgical embolectomy.

Multiplex PCR for simultaneous detection of the most frequent T cell receptor-delta gene rearrangements in childhood ALL.

A rapid and simple multiplex polymerase chain reaction (PCR) is described that is capable of identifying the six most frequent rearrangements of the T cell receptor (TCR)-delta gene segments in childhood acute lymphoblastic leukemia (ALL). The PCR products amplified in a single reaction are of different size for each TCR-delta gene rearrangement. Therefore, they are readily and unambiguously distinguished after agarose gel electrophoresis and assigned to a specific V-D-J gene rearrangement. There is no need for labor-intensive and time-consuming Southern blot hybridization or nested PCR. To evaluate the multiplex assay we chose 45 DNA samples of childhood ALL analyzed beforehand for TCR-delta gene rearrangements by Southern blot and single PCR of which 30 showed TCR-delta gene rearrangements. The multiplex PCR results corresponded to the Southern blot and single PCR analyses. The described multiplex PCR enables the detection of clonal markers in about 50% of patients in order to monitor minimal residual disease (MRD) in prospective studies with a high turnover of samples.

Drug coated stents for carotid intervention.

Carotid endarterectomy has demonstrated its superiority over medical treatment of symptomatic as well as asymptomatic stenosis of the extracranial carotid artery. Although minimally invasive methods initially failed to produce similar results, stent implantation is becoming an alternative technique for stroke prophylaxis with technical advances, cerebral protection and careful patient selection. Even though restenosis does not seem to be a major limitation compared to coronary interventions, in-stent restenosis might occur more frequently with an increasing number of procedures performed and longer follow-up periods. Drug eluting stents have shown to attenuate this complication. Currently, no clinical data on drug eluting stents in carotid arteries are available. This article discusses the current literature on carotid artery stenting and the potential role of drug eluting stents in this field.

Developing an Electronic Medical Record for Interlinked Care Services in Haiti.

A large clinical care and research organization in Haiti required an electronic medical record system (EMR) to serve the needs of its 30 interlinked clinical programs. After assessing available open source software, the local team designed and implemented a modular proprietary EMR that is improving data quality and patient care. Despite the many benefits of existing open source medical record systems, clinical centers with complex workflow patterns--even those in resource-limited settings--should consider developing sustainable, local systems that fit their care model.

Tc-99m-labeled endothelin derivative for imaging of experimentally induced atherosclerosis.

OBJECTIVE: to characterize the potential of an endothelin derivative labeled with technetium-99m (Tc-99m) for the imaging of experimentally induced atherosclerosis. METHODS: neointima of different cellularity and severity of stenosis was induced in 32 rabbits by balloon denudation followed by distinct dietary regimens and drug application. Angiograms and scintigrams after injection of the Tc-99m-labeled endothelin derivative were obtained. The aorta was dissected for autoradiography, sudan-III-staining, morphometry, and immunohistology. RESULTS: the lesions induced could be detected in vivo (whole body scintigram) in all the animals 15 min after the injection of the Tc-99m endothelin derivative. Autoradiography revealed a strong relationship between tracer accumulation and sudan-III-staining of lesions. Accumulation of the endothelin derivative correlated with the number of neointimal smooth muscle cells (SMC), but not with the number of medial SMC, neointimal macrophages, and neointimal area. CONCLUSIONS: the results indicate that in vivo imaging of atherosclerosis with an endothelin derivative is a feasible method of detecting and characterizing atherosclerotic arterial wall lesions at early stages.

Rhenium-188 for inhibition of human aortic smooth muscle cell proliferation.

PURPOSE: To evaluate dose-dependent growth-modulating effects of the beta-gamma emitter Rhenium-188 on cultured human aortic smooth muscle cells (haSMC). METHODS AND MATERIALS: HaSMC were plated in 25 cm(2) flasks. Two days after plating, cells were incubated with the Re-188 (beta E(max) 2.12 MeV, tissue range(max) < 10 mm, T(1/2) 17 h) for five days. The doses administered were 0.2 Gy, 1, 4, 6, 8, 16, and 32 Gy. After five days, the radionuclide was removed. Cell growth, cell cycle distribution, and clonogenic activity were analyzed for the following 25 days. RESULTS: The 0.2 and 1 Gy groups did not show relevant growth-inhibiting effects compared to the control groups. The 4 to 32 Gy groups presented dose-dependent growth inhibition, with a complete growth arrest of the 16 and 32 Gy groups. Clonogenic activity of the smooth muscle cell was strongly inhibited from doses > or =8 Gy. Flow cytometry showed a lasting dose-dependent G2/M phase block. CONCLUSION: Smooth muscle cell (SMC) growth can be controlled effectively with Re-188 for at least 25 days after radiation in vitro. As the first four weeks after arterial angioplasty are crucial concerning neointimal formation, Re-188 may be a valuable radionuclide to inhibit restenosis after arterial angioplasty.

Noninvasive procedures for diagnosis of renovascular hypertension in renal transplant recipients--a prospective analysis.

The purpose of this study was to clarify the selectivity and specificity of noninvasive procedures for diagnosis of clinically suspected posttransplant renovascular hypertension. We prospectively investigated 25 renal transplant recipients with arterial hypertension and clinically suspected stenosis of the graft artery (8 female and 17 male patients; ages 45 +/- 15 years). We performed a captopril test with 25 mg captopril (n = 25), renography with technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) before and after angiotensin-converting enzyme (ACE) inhibition with determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) (n = 23) and color-coded duplex ultrasonography of the transplant kidney vessels (n = 24). Renal transplant artery stenosis (RTAS) was excluded by renal arteriography in 20 patients and by operative evaluation or clinical follow-up in 5 patients. We identified 4 patients with RTAS and renovascular hypertension. The noninvasive methods showed the following results (sensitivity/specificity): (1) captopril test: 75%/67%; (2) renography combined with ACE-inhibition: 75%/84%; and (3) color-coded duplex ultrasonography: 100%/75%. We conclude that in patients with clinical evidence of RTAS most noninvasive diagnostic procedures are not sufficiently accurate to exclude the diagnosis. Only color-coded duplex ultrasonography did not fail to detect all patients with RTAS and may act as a screening test. Intraarterial renal angiography remains the most reliable and as-yet indispensable diagnostic test for transplant recipients to rule out RTAS.

Molecular imaging of atherosclerosis using a technetium-99m-labeled endothelin derivative.

UNLABELLED: Endothelins have been implicated in the pathogenesis of atherosclerosis and restenosis. The aim of this study was to characterize the potential of an endothelin derivative labeled with 99mTc for imaging experimental atherosclerosis in vivo. METHODS: Atherosclerosis was induced by balloon denudation of the infrarenal aorta in eight New Zealand white rabbits followed by a 6-wk period of a standard or 0.5% cholesterol diet in four animals, respectively. Another four rabbits served as controls, without balloon denudation and cholesterol feeding. Digital subtraction angiograms and planar whole-body scintigrams were obtained after intravenous injection of 74 MBq of the 99mTc-labeled endothelin derivative. The aorta was dissected for autoradiography, sudan-III staining, morphometry and immunohistology (anti-alpha-actin, RAM 11) 5 hr after injection. RESULTS: The lesions induced in the infrarenal aorta could be detected in vivo (whole-body scintigrams) in all treated animals only 15 min after injection of 99mTc-endothelin derivative. Autoradiography of the excised aorta revealed good correlation of tracer accumulation and sudan-III-stained lesions. The ratio of accumulation between the induced lesions and untreated vessel wall was 6.8 +/- 1.4 in the cholesterol-fed animals and 6.3 +/- 1.8 in the animals without cholesterol feeding. Accumulation of the endothelin derivative correlated with the number of smooth muscle cells (r = 0.924) but not with the amount of macrophages, the area or the maximum thickness of the plaques. CONCLUSION: Scintigraphic visualization of experimentally induced atherosclerosis in vivo is feasible using an endothelin derivative labeled with 99mTc.

Ablation characteristics of arterial vessel walls irradiated with the pulsed dye laser--an analysis of variance.

BACKGROUND AND OBJECTIVE: Since most clinical laser angioplasties require the use of over-the-wire delivery systems, we studied the effects of pulsed dye laser energy (504 nm, 1.4 microseconds on arterial vessel walls in combination with a multifiber catheter system. MATERIAL AND METHODS: Postmortem arterial segments (n = 368) were exposed under blood or saline. Laser pulses (n = 100-800) were transmitted via 9F-multifiber-catheters, at energy densities of 3-16 J/cm2. Ablation characteristics revealed by histologic examination and morphometry were analyzed by multiple analysis of variance. RESULTS: Ablation occurred more frequently in saline compared to blood. Below an energy density of 10 J/cm2 ablation occurred in saline only. Specimens irradiated under blood showed only thermal changes at 10 J/cm2. In saline, 92% of normal, 88% of fibro-fatty and 60% of calcified tissue showed ablation at 13 J/cm2. The average ablation threshold in saline was about 3-4 J/cm2 per pulse for normal tissue, 5 J/cm2 for fatty plaques, and 8-9 J/cm2 for calcified plaques. In blood, the average ablation thresholds did not differ significantly between the different stages of arteriosclerosis (12 J/cm2 for normal tissue, 11 J/cm2 for fatty plaque, and 10 J/cm2 for calcified tissue). Carbonization and vacuolization were seen regularly at energy levels > or = 13.4 J/cm2. CONCLUSIONS: Selective ablation of arteriosclerotic tissue with the pulsed dye laser could not be found. Further investigation is needed before an effective ablation of arteriosclerotic arterial tissue can be expected.

Comparison of magnetic resonance imaging methods for examinations of abdominal aortic aneurysms.

RATIONALE AND OBJECTIVES: Different magnetic resonance imaging techniques were compared with respect to available anatomic information regarding abdominal aortic aneurysms (AAA) and regions involved in thrombosis. METHODS: Twenty patients with AAA were examined by turbo spin-echo (TSE) imaging of coronal and transverse slices, resulting in black blood images. Bright blood imaging was performed using a spoiled gradient-echo sequence with gradient moment nulling. Sets of 25 to 50 thin slices were recorded sequentially in a single slice mode using coronal and transverse orientation. Both sets of bright blood images were reconstructed by maximum intensity projection. RESULTS: In all patients, the size and shape of the AAA could better be assessed by the TSE images than by the gradient-echo images. In contrast, reliable differentiation of thrombotic areas and of the perfused lumen was possible in only 56% of the slices recorded by TSE imaging but in 94% of the gradient-echo images. The two-dimensional inflow technique provided clearly higher sensitivity even to slow blood flow than TSE imaging. Maximum intensity projection reconstructions from sets of coronal two-dimensional inflow images often did not depict the lower part of the AAA because of saturation effects, whereas sets of transverse slices provided complete angiograms of the aortoiliac vascular tree. DISCUSSION: At this time, no single magnetic resonance method can provide all essential information. A comprehensive examination should include TSE imaging for topographic assessment and transverse two-dimensional inflow imaging for analysis of thrombotic areas.

Renal handling and physiologic effects of the paramagnetic contrast medium Gd-DOTA.

Gadolinium DOTA (Gd-DOTA) is a magnetic resonance (MR) contrast agent similar to Gd-DTPA but with greater stability in vitro. The effects of a high intravenous dose (0.5 mmol/kg) of Gd-DOTA (1360 mOsm/kg) on renal excretory function and its general systemic effects are examined in this animal study. This dose was selected to accentuate and better define the qualitative nature of these effects. A decrease in arterial pressure of 8% (131.9 +/- 6.8 at 120 minutes versus a control of 142.8 +/- 3.7 mm Hg, mean +/- standard error of mean, no significant change in electrocardiogram (ECG) lead II, a 16% increase in renal blood flow (106.0 +/- 5.4 at 7.5 minutes versus 91.2 +/- 3.2 ml/min), and a decrease in arterial hematocrit of 9% (38.9 +/- 1.5 at 120 minutes versus 41.9% +/- 1.7%) were noted. In general, qualitatively similar effects have been noted as a nonspecific effect of other hyperosmolar solutions. The filtration fraction decreased (0.23 +/- 0.01 at 7.5 minutes versus 0.28 +/- 0.02) followed by a rapid return to baseline values. No significant change was noted in glomerular filtration rate throughout the experimental protocol. Urine flow increased nearly 1.5-fold and osmolal clearance (Cosm) increased approximately 1.5 times. A natriuresis occurred as the fractional excretion of sodium (FENa+) increased from a control value of 3.5 +/- 0.3 to 5.2 +/- 0.5 at 7.5 minutes. The systemic and renal physiologic effects of high-dose intravenous Gd-DOTA on the kidney reflects a nonspecific, osmotically induced alteration. These data suggest that the main systemic and renal physiologic actions of Gd-DOTA are a nonspecific response to agent osmolality that is similar qualitatively to conventional, water-soluble contrast media.

Local intra-arterial drug delivery for prevention of restenosis: comparison of the efficiency of delivery of different radiopharmaceuticals through a porous catheter.

RATIONALE AND OBJECTIVES: Several radiopharmaceuticals were administered through a porous balloon catheter to compare the absolute amount deposited and the retention in the vessel wall. The reported efficiency of local drug delivery ranges from 0.001% to 0.1%, with poor retention after 24 hours. METHODS: An endothelin derivative (n = 6), pertechnetate (n = 6), hexamethylpropylene amineoxime (HMPAO) (n = 5), ethyl cysteinate dimer (ECD) (n = 5), and tin colloid (n = 5) were labeled with 185 MBq/mL 99m-technetium. After balloon denudation of the infrarenal aorta in 27 New Zealand White rabbits, 100 microL of each agent was administered through a porous balloon at a pressure of 4 bar. Dynamic and static whole-body scintigrams were obtained for 24 hours. The infrarenal aorta was excised and the activity calculated in a gamma counter. RESULTS: Apart from their retention in the region of local administration, the radiopharmaceuticals showed different distribution patterns. The highest regional tracer retention was observed with HMPAO. After administration of HMPAO, a significant difference between regional (vessel wall plus surrounding tissue: 14.5% of injected dose [ID]/24 hours) and local (vessel wall: 1.8% ID/24 hours) delivery was found. In contrast, ECD was eliminated quickly (local retention after 24 hours = 0% ID). The retention efficiencies were HMPAO > endothelin derivative > tin colloid > pertechnetate > ECD. CONCLUSIONS: The different physicochemical and pharmacokinetic properties of radiopharmaceuticals resulted in different delivery efficiencies after local application.

Covered stents for prevention of restenosis. Experimental and clinical results with different stent designs.

RATIONALE AND OBJECTIVES: Metallic stents in small vessels go along with a significant risk of restenosis and reocclusion. Different models of stents and covering materials have been purported to prevent intraluminal neointimal proliferation by cover-based closure of the spaces in the wire mesh. METHODS: Tantalum stents covered with polyethylacrylate/polymethylmethacrylate (PEM) were implanted in the infrarenal aorta of six New Zealand white rabbits by aortotomy and compared with eight rabbits treated with uncovered tantalum stents. For deployment, covered and uncovered stents necessitated a 7-French (F) and 5-F sheath, respectively. In addition, nine human patients with arteriosclerotic lesions of the superficial femoral arteries (stenosis > 5 cm or total occlusion) were treated percutaneously with a Dacron-covered nitinol vascular stent via a 9-F sheath. Patients were followed for a mean of 13.5 months, and control angiography was performed after 6 months. RESULTS: Experimental placement of the tantalum Wiktor stent was feasible technically in all cases. Five of six stents covered with PEM were occluded 3 days after placement despite the intravenous use of heparin and aspirin. In the group with uncovered stents, no area of stenosis greater than 10% was observed. There was a neointimal layer of 89 +/- 68 microns around the stent wires. Stent placement was successful in all patients. In four patients, a hyperergic reaction occurred, resulting in noninfectious periarteriitis. This complication was treated successfully with nonsteroidal antiinflammatory drugs. The primary patency was 50%, and the secondary patency (after application of a second covered stent in two patients) was 63%. CONCLUSIONS: The uncovered stent induces little neointimal proliferation around the stent wires. The insertion of stents covered with PEM into the rabbit aorta was accompanied by a strong thrombotic reaction, despite sufficient anticoagulation. Dacron-covered nitinol stents showed a surprisingly high restenosis rate after 9 months of follow-up. Further research concerning the in vivo properties of new covering materials is mandatory before routine vascular clinical application.

Lipids in bone tumors assessed by magnetic resonance: chemical shift imaging and proton spectroscopy in vivo.

The methods of fat and water selective magnetic resonance (MR) imaging and localized 1H MR spectroscopy were evaluated in the course of 37 examinations on 27 primary bone tumors. These methods are capable of demonstrating small amounts of lipids inside the tumors and subtle edema in the adacent bone marrow, in contrast to the usually applied spin-echo and gradient-echo sequences providing signals dependent on the total proton density and on the relaxation times. The tumor masses of the malignant tumors were free of signals in the fat selective images, whereas in three out of six osteochondroma fat signals could be detected. Localized MR spectroscopy was more sensitive even to very low lipid content (lipid portion < 0.5%) in the tumors and revealed signals with J-coupling from seven out of 13 malignant tumors.

Eosinophilia-myalgia syndrome: findings at MR imaging and proton spectroscopy of the lower leg.

Five magnetic resonance (MR) studies of the lower leg were performed in three patients with eosinophilia-myalgia syndrome (EMS). The 1H spectroscopic and imaging findings were compared with seven examinations of age-matched healthy controls. Standard imaging with proton density-, T1-, and T2-weighted spin-echo (SE) sequences at 1.5 T showed marked atrophy of the calf muscles and slightly increased signal strength of muscle tissue in T2-weighted SE images. The application of frequency selective chemical shift imaging (SENEX) exhibited skin changes similar to those of scleroderma with increased water content and thickened cutis in the water selective images. In one patient the tibialis muscles showed irregular structures, but no fatty degeneration as demonstrated in the fat selective images. Proton signals from volume elements of (20 mm)3 within the soleus and gastrocnemius muscle were recorded by the PRESS localization method. A reduction of the creatine/water and the choline/water ratios was found in the 1H spectra from the EMS patients compared to the controls. Localized 1H spectroscopy exhibited modified distributions of the lipid signals in two EMS patients with slightly elevated signals from unsaturated fatty acids. The transverse relaxation of choline and creatine signals was accelerated in both examinations of one patient compared with the healthy controls.