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Biomedical subjects

J Brossmann

Publications and source records attributed to J Brossmann.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Percutaneous therapy of occlusions of calf arteries with newly developed hydrodynamic thrombectomy catheter, Angiojet LF140].

PURPOSE: To evaluate the rheolytic thrombectomy catheter Angiojet LF140 (RTC) for treatment of calf artery occlusions. PATIENT AND METHOD: A 47-year-old male patient with an 8 cm measuring occlusion of the femoropopliteal and all calf vessels, suffering from limb threatening ischemia for 21 days, was treated with hydrodynamic thrombectomy (RT) using the modified RTC LF140. RESULTS: Most of the occluded segments could be successfully recanalized with the RTC. 450 ml of heparinized saline were injected. Parts of the tibial posterior artery and the fibular artery remained occluded. Additional long-term fibrinolysis therapy was administered (24 h), until all lower limb arteries were completely recanalized (+3 according to Rutherford). CONCLUSION: The modified RTK LF140 allows the treatment of acute thrombotic occlusions, even small caliber vessels. The device fails to remove organized and walladherent thrombus.

Catheterization↗
PubMed1998

[Percutaneous thrombectomy and mechanical thrombolysis].

Treatment of acute embolic and thrombotic occlusions of arteries has to be initiated immediately to save the limb at risk. Surgery has been the treatment of choice for the last decades. Percutaneous mechanical methods for thrombectomy and thrombolysis have evolved and offer alternative treatment options, reducing the peri-operative risk. Percutaneous aspiration thrombembolectomy (PAT), recirculation thrombectomy with the Amplatz device, and different systems for hydrodynamic thrombectomy and thrombolysis (Angiojet, Hydrolyer, S.E.T. catheter) are routinely used for percutaneous thrombectomy and mechanical thrombolysis. These 3.5-10 F systems allow for the rapid removal of a fresh clot from different vascular regions. Complete removal of the clot can be achieved in 19-49%; adjunctive use of other percutaneous methods (thrombolysis and thrombectomy: 60-80%; PTA and atherectomy: 81-100%) results in primary success rates of 67-100% for recanalization of acutely occluded vessels. Primary indications for percutaneous thrombectomy and mechanical thrombolysis are acute occlusions of peripheral arteries and dialysis fistulas; limited experience exists for the treatment of occlusions of the visceral and pelvic vessels. Percutaneous methods seem promising for treatment of acute pulmonary embolism.

Acute Disease↗
PubMed1998

Percutaneous balloon-assisted thrombectomy: preliminary in vivo results with an expandable vascular sheath system.

PURPOSE: To test an expandable vascular sheath system for percutaneous transcatheter balloon-assisted thrombectomy in vivo. MATERIALS AND METHODS: A 9-F expandable vascular sheath system was used. The system consisted of a sheath with a deployable funnel configuration and a 3-F balloon catheter used coaxially. Thrombus was created in the inferior vena cava of 24 rabbits. Thrombus with a mean weight +/- 1 standard deviation of 1,028 mg +/- 67 was removed percutaneously with the expandable sheath system at 2 days (n = 16) and 7 days (n = 8) after formation; 7-day patency was examined after removal of 2-day-old thrombus (n = 8). Histologic examination was performed in the inferior vena cava. RESULTS: In all cases of 2-day-old occlusion, complete patency of the inferior vena cava was achieved. In cases of 7-day-old occlusion, patency could be completely restored in four (50%) cases; in two (25%) cases each, there was partial removal or no thrombus could be extracted. Histologic findings were comparable with those observed after balloon embolectomy. CONCLUSION: Percutaneous transcatheter balloon-assisted embolectomy is feasible with the expandable vascular sheath system.

Animals↗
PubMed1998

Hip joint fluid: detection and distribution at MR imaging and US with cadaveric correlation.

PURPOSE: To define the magnetic resonance (MR) imaging appearance of a hip effusion. MATERIALS AND METHODS: Fifty-two asymptomatic hips in 26 volunteers aged 20-37 years and five fractured hips were imaged at 1.5 T with T2-weighting in three planes. Images were computer digitized and analyzed for hip fluid volume and visually assessed for the presence and width of fluid pockets (in millimeters) seen in the acetabular notch; recesses anterior, posterior, and lateral to the femoral head; and recesses anterior, posterior, and medial to the femoral neck. Cadaveric hips were also injected with graduated amounts of saline (1-20 mL), and sequential MR and ultrasound images were obtained. RESULTS: Computer analysis yielded an average fluid volume of 2.7 mL (range, 0.7-5.6 mL) in asymptomatic and 6.1 mL (range, 1.7-11.6 mL) in symptomatic hips. The mean difference between the right and left hips was 0.8 mL (range, 0.0-2.9 mL). Discrete fluid pockets, sometimes measuring greater than 5 mm in width, were commonly seen in asymptomatic hips. Distention of the capsule by at least 5 mm along the length of the femoral neck was almost always seen after injection of 5 mL of saline and was consistently seen after injection of 10 mL of saline into cadaveric hips. CONCLUSION: Fluid adjacent to the entire length of the femoral neck, measuring at least 5 mm in width, is compatible with a joint effusion.

Acetabulum↗
PubMed1998

[PTA of the brachiocephalic arteries].

PURPOSE: Assessment of the technical success and mid-term success of PTA of brachiocephalic occlusive disease. MATERIAL AND METHODS: 24 patients, who were treated interventionally because of stenoses of the brachiocephalic arteries were enrolled into this prospective study. In total there were 27 lesions (26 arteriosclerotic lesions and one dissection with pseudoaneurysma). 18 lesions were located in the subclavian artery (extending into the axillar artery in one case), 4 in the brachiocephalic trunk, three in the common carotid artery and two in the vertebral artery. As adjunctive to balloon dilatation 8 stents were implanted. RESULTS: Technical success was achieved in 24/27 lesions. There was an embolic complication in one of 27 interventions. 15/24 patients with 17 treated lesions underwent control angiography with a mean follow-up of 14 months. Follow-up angiography revealed one occlusion and three significant restenoses. 5/24 patients agreed only to clinical follow-up and Doppler examinations, three were lost and one patient died. CONCLUSION: PTA of brachiocephalic occlusive disease showed good technical success. Additional implantation of stents may be useful. Midterm success is satisfactory.

Aged↗
PubMed1998

[Pseudo-rupture of the femoral artery following balloon angioplasty].

Following PTA of a superficial femoral artery stenosis, painful swelling of the vastus medialis muscle occurred at mobilization of the patient 24 hours after the intervention. Duplex sonography and angiography revealed bleeding from a muscular branch of the SFA. The complication was successfully treated by embolization.

Aged↗
PubMed1997

[Midterm follow-up after Cragg stent placement in iliac arteries].

PURPOSE: Evaluation of midterm success and patency rates after placement of Cragg stents in iliac arteries. MATERIAL AND METHODS: During a period of 26 months 16 patients, with a total of 19 iliac lesions were treated percutaneously by placement of 20 stents. Indications of stent placement were iliac occlusion in 4 cases and high-grade iliac stenoses in 15 cases. Indication for stent placement in the stenotic lesions were insufficient results following balloon angioplasty in 11 cases and extensive dissection in 4 cases. RESULTS: The ankle-brachial index was improved from 0.53 +/- 0.28 to 0.85 +/- 0.26 immediately after the intervention and was 0.80 +/- 0.15 at 16 months follow-up. Cumulative patency rate was 71% after 12 months. CONCLUSION: The occlusion and restenosis rates are high. Disadvantages of Cragg stents are low flexibility and a large bore introducer system. The radiopacity of the Cragg stent is advantageous for fluoroscopic positioning.

Aged↗
PubMed1997

Kinematic MR imaging of the ankle--initial results with ultra-fast sequence imaging.

PURPOSE: In order to evaluate the advantages of ultra-fast MR sequences, kinematic MR imaging studies were performed in 4 patients with osteochondritis dissecans of the talus and in 12 healthy volunteers. MATERIAL AND METHODS: The patients and volunteers were placed inside a custom-made positioning device. Sagittal ultra-fast T2-weighted turbo gradient-echo sequences and HASTE sequences were obtained during active joint motion from dorsiflexion to plantar flexion. Eight sagittal slices were scanned separately to cover this ankle motion. In each slice, 8 to 10 images were obtained in 12-s or 18-s periods. RESULTS: Adequate image quality for analyzing the normal kinematics of the ankle was obtained in all subjects. At surgery, the osteochondral fragment was found to be mobile in 3 of the 4 of the patients. In none of these cases was fragment mobility observed on kinematic MR imaging. No motion of the fragments was observed in the fourth patient, neither at surgery nor on kinematic MR imaging. CONCLUSION: Ultra-fast MR imaging sequences made it possible to produce kinematic MR imaging studies of active joint motion. The positioning device was useful for guiding joint motion in patients and for obtaining adequate image quality.

Adult↗
PubMed1997

Dual-energy X-ray absorptiometric densitometry in osteoarthritis of the hip. Influence of secondary bone remodeling of the femoral neck.

PURPOSE: The aim of this study was to evaluate the influence of buttressing on bone densitometry measurements in the femoral neck, in Ward's triangle, and in the greater trochanter. In addition, we attempted to establish the length of the femoral axis (FAL) and the true length of the femoral neck (FNL) as potential correlates with osteoarthritis (OA) or with buttressing. MATERIAL AND METHODS: Our study comprised 101 hips in 68 adult patients. Conventional radiographs of the hip joints were obtained in order to assess the presence and extent of OA by means of the 6-step grading system introduced in 1990 by CROFT et al., and in order to measure the cortical thickness at the medial aspect of the femoral neck. In addition, FAL and FNL were measured. All patients underwent dual energy x-ray absorptiometry so that bone density could be assessed in the femoral neck, in Ward's triangle, and in the greater trochanter. The Spearman rank correlation was used to compare the measurements. RESULTS: Statistical analysis showed a significant positive correlation between cortical thickness and bone density in the femoral neck and in Ward's triangle. No correlation was found between cortical thickness and bone density in the greater trochanter, nor between cortical thickness and OA, FNL, and FAL, nor between OA and bone density, FNL, and FAL. CONCLUSION: Buttressing influenced our bone density measurements in the femoral neck and in Ward's triangle. It did not affect the region of the greater trochanter which may therefore be the best region of interest for a long-term follow-up of bone density in patients with OA.

Absorptiometry, Photon↗
PubMed1997

Short echo time projection reconstruction MR imaging of cartilage: comparison with fat-suppressed spoiled GRASS and magnetization transfer contrast MR imaging.

PURPOSE: To evaluate short echo time (TE) projection reconstruction magnetic resonance (MR) imaging in the detection of cartilage lesions. MATERIALS AND METHODS: Twenty-seven cartilage regions of 10 human patellar specimens were examined with the following MR sequences: short TE projection reconstruction (repetition time msec/TE msec, 400/0.15), fat-suppressed three-dimensional spoiled gradient-recalled acquisition in the steady state (Spoiled GRASS) (50/10, 60 degrees flip angle), and magnetization transfer contrast (MTC) subtraction (400/6). MR findings were correlated with histopathologic grading of the cartilage. RESULTS: For detection of cartilage lesions, sensitivity of projection reconstruction imaging (100%) was significantly greater (P = .03) than that of MTC (62%) but not significantly greater (P > .05) than that of Spoiled GRASS (81%) imaging. Accuracy of projection reconstruction was significantly greater than that of MTC (P = .004) and Spoiled GRASS (P = .03) imaging. Unmasking of collagen fibers was most predictive of abnormal signal intensity of the cartilage with all sequences. CONCLUSION: In vitro, short TE projection reconstruction MR imaging provides superior delineation of cartilage lesions when compared with two other sequences. On Spoiled GRASS and MTC images, signal intensity of the superficial layer of cartilage is not a reliable sign for surface integrity.

Aged↗
PubMed1997

Collateral ligaments of the elbow: conventional MR imaging and MR arthrography with coronal oblique plane and elbow flexion.

PURPOSE: To determine the best plane and position of the elbow for optimal visualization of normal and abnormal collateral ligaments with conventional magnetic resonance (MR) imaging and MR arthrography, to determine the normal appearance of the collateral ligaments at MR arthrography and to assess use of MR arthrography in evaluation of collateral ligamentous lesions. MATERIALS AND METHODS: Nine cadaveric elbow specimens were imaged with and without intraarticular administration of gadolinium-containing solution in several planes that were identified as potentially useful in a pilot study in two specimens. MR imaging findings were compared with anatomic findings. RESULTS: Normal and abnormal ligaments were best depicted in a 20 degrees posterior oblique coronal plane in relation to the humeral shaft with the elbows extended and a coronal plane aligned with the humeral shaft with the elbows slightly flexed (20 degrees-30 degrees of flexion). Gadolinium enhancement improved the delineation of normal and abnormal ligaments on T1-weighted images in each case. CONCLUSION: The posterior oblique coronal plane with the elbows extended or the coronal plane aligned with the humeral shaft with the elbows slightly flexed allows accurate assessment of the collateral ligaments. Gadolinium-enhanced MR arthrography of the elbow seems to be a promising technique.

Aged↗
PubMed1997

Symptomatic herniation pits of the femoral neck: anatomic and clinical study.

OBJECTIVE: The purpose of this study was to investigate the pathogenesis of herniation pits of the femoral neck, which are frequently considered a normal variant, and to describe the imaging abnormalities of such pits in three symptomatic patients. CONCLUSION: The changing relationship between the joint capsule and the iliopsoas muscle appears to be important in the pathogenesis of the herniation pit, especially in athletic persons. In some cases, these pits may enlarge, the overlying cortex may fracture, and significant clinical manifestations may be apparent.

Adult↗
PubMed1997

Common carotid artery bifurcation: preliminary results of CT angiography and color-coded duplex sonography compared with digital subtraction angiography.

OBJECTIVE: The purpose of this study was to compare the abilities of color-coded duplex sonography, CT angiography, and selective digital subtraction angiography to reveal disease requiring surgery in patients with occlusive disease of the carotid bifurcation. MATERIALS AND METHODS: Fifty-six carotid arteries in 28 patients who had 48 carotid stenoses and symptomatic cerebrovascular disease were prospectively studied by selective digital subtraction angiography, color-coded duplex sonography, and CT angiography. CT data were displayed in maximum intensity projection. The degree of stenoses revealed were graded as mild, moderate, severe, and occluded according to North American Symptomatic Carotid Endarterectomy Trial criteria. The results of CT angiography and color-coded duplex sonography were correlated with the gold standard of digital subtraction angiography. RESULTS: Grading of stenoses on CT angiography agreed with grading of stenoses on digital subtraction angiography in 89% of cases. All high-grade stenoses and occlusions revealed on CT angiography were correctly interpreted by all observers. For stenoses revealed by color-coded duplex sonography and digital subtraction angiography, observers' agreement was 75%. Two severe stenoses were incorrectly graded as occluded by the interpreter of the color-coded duplex sonograms. Also, one occluded carotid artery was misdiagnosed as moderate stenosis. CONCLUSION: Our results indicate that CT angiography is superior to color-coded duplex sonography for evaluating carotid disease and determining disease requiring surgery. CT angiography warrants further investigation in a larger group of patients.

Angiography, Digital Subtraction↗
PubMed1997

MR imaging truncation artifacts can create a false laminar appearance in cartilage.

OBJECTIVE: The purpose of this study was to investigate the laminar appearance of cartilage on MR images. MATERIALS AND METHODS: Theoretical modeling of truncation artifacts was used to predict spatial patterns and associated intensity variations in MR imaging. A numerical simulation of a ring model was used to show truncation artifacts as a function of the angle in the image plane for unequal in-plane resolutions. MR imaging of 10 cadaveric human patellae at several resolutions used an imaging protocol that produced high-contrast images of cartilage. The high-resolution image of each MR imaging set was reduced in resolution by low-pass filtering and compared with the acquired images of equivalent resolution. Variable-resolution images of the patella of a healthy human volunteer were also acquired. RESULTS: Truncation artifacts from opposing cartilage edges can create false laminae and artifactual intensities. The resulting geometric variations can alter the apparent width of the cartilage as well. The intensity variations produced by truncation artifacts can be as much as 22% of the actual intensity. The most pronounced artifactual trilaminar appearance occurs when cartilage thickness exceeds the image resolution by a factor of 4. Truncation artifacts vary as a function of the angle in the imaging plane for unequal resolutions in the two directions. CONCLUSION: Truncation artifacts can produce an artifactual laminar appearance in cartilage and alter the apparent cartilage width.

Artifacts↗
PubMed1997

MR imaging of enhancing intraosseous disk herniation (Schmorl's nodes).

OBJECTIVE: This study was conducted to show vascularization of Schmorl's nodes with enhanced MR imaging and to correlate this finding with clinical complaints. MATERIALS AND METHODS: Retrospectively, 412 gadopentetate dimeglumine-enhanced MR imaging examinations of the lumbar and thoracic spine of 372 patients were reviewed for Schmorl's nodes, vascularization of Schmorl's nodes, and associated bone marrow edema. Sagittal T2-weighted spin-echo and unenhanced and enhanced T1-weighted spin-echo images with and without fat suppression were evaluated in symptomatic and asymptomatic patients. RESULTS: Of the 372 patients, 142 (38%) had 341 Schmorl's nodes. Gadopentetate dimeglumine-enhanced MR imaging revealed vascularized tissue in 30 Schmorl's nodes of 23 patients (mean age of patients, 53 years old). Associated bone marrow edema was found in nine of 30 vascularized Schmorl's nodes. The mean diameter (8.2 mm) of the nine vascularized Schmorl's nodes that were surrounded by bone marrow edema was significantly (p < .05) greater than the mean diameter (6.4 mm) of the 21 vascularized Schmorl's nodes that had no bone marrow edema. The vascularized Schmorl's nodes were significantly (p < .05) smaller in the seven asymptomatic patients (mean, 5.2 mm) than in the 23 patients with back pain (mean, 7.9 mm). We saw bone marrow edema adjacent to Schmorl's nodes less frequently in asymptomatic patients (one of seven) than in symptomatic patients (10 of 23). CONCLUSION: Vascularized Schmorl's nodes were larger and more frequently associated with bone marrow edema in patients with back pain than in asymptomatic patients. Enhanced MR images of Schmorl's nodes revealed vascularity, which was not shown on unenhanced MR images.

Adult↗
PubMed1997

Measurements of cortical thickness in experimentally created endosteal bone lesions: a comparison of radiography, CT, MR imaging, and anatomic sections.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of cortical measurements of experimentally created endosteal cortical lesions and to assess the sensitivity of radiography, CT, and MR imaging in the detection and measurement of such lesions. MATERIALS AND METHODS: Thirty-six cortical lesions were created in three fresh cadaveric femurs. After performing radiography, CT, and MR imaging, we sectioned the specimens in the axial plane. We then measured the remaining cortex at the lesions and the normal cortex adjacent to the lesions on all images and corresponding anatomic sections. The measurements of thickness of the cortex as seen with the different imaging methods and the anatomic sections were compared. Measurements were repeated to evaluate the influence of different window settings on the MR imaging measurements. RESULTS: When measured on radiographs, cortical thickness was overestimated in 58% of lesions. With CT, cortical thickness was overestimated by 0-15% in 94% of all lesions. With MR imaging, cortical thickness was uniformly underestimated by 3-17%. Measurements made on MR images varied according to different window settings. The proton density-weighted sequence yielded the highest sensitivity in the detection of shallow cortical lesions; the T1-weighted spin-echo sequence was the least sensitive of the MR sequences. CONCLUSION: In our cadaveric study, cortical thickness in the presence of endosteal lesions was overestimated on radiographs and CT scans and underestimated on MR images. Measurements derived from MR imaging are strongly influenced by the window setting. MR imaging with the proton density-weighted sequence is the most sensitive for detection of shallow cortical lesions and is more sensitive than CT.

Bone Neoplasms↗
PubMed1997

MR imaging signal-intensity abnormalities after placement of arterial endoprostheses.

OBJECTIVE: Our objectives were to describe changes in T2-weighted MR images of patients who had undergone implantation of an endoluminal stent-graft and determine the rate of early reocclusion in patients with abnormal MR findings. SUBJECTS AND METHODS: Twenty-nine patients with 26 occlusions (average length, 8.7 +/- 5.6 cm) and three dissections of the superficial femoral artery were treated with 45 endoluminal stent-grafts. T2-weighted gradient-echo and T2-weighted turbo spin-echo MR images were obtained for all patients at 48 hr and at 4 weeks after stent-graft placement. We reviewed the MR imaging studies to assess the extent and severity of tissue alteration at the site of stent-graft implantation. RESULTS: Technical success rate of stent-graft placement was 100%. Three signal-intensity patterns were seen on MR images obtained at 48 hr: normal signal intensity (n = 8), subtle perivascular signal-intensity abnormalities at the site of stent-graft implantation (n = 11), and extensive signal-intensity abnormalities from the adductor canal to the subcutis (n = 10). Twenty of 21 patients with abnormal signal intensity on MR images had fevers and pain at the implantation site. Clinical signs of deep vein thrombosis, a diagnosis excluded on the basis of phlebography, were seen in the 10 patients with extensive signal-intensity abnormalities. In two of these 10 patients, the superficial femoral artery reoccluded within 4 weeks of implantation. MR images obtained at 4 weeks showed no signal-intensity abnormalities in any of the 29 patients. CONCLUSION: MR findings of perivascular signal-intensity abnormalities after implantation of endoluminal stent-grafts are associated with clinical complications such as local pain and fever. Care should be taken to avoid confusing the clinical signs of the postimplantation syndrome at 48 hr with deep vein thrombosis.

Aged↗