Biomedical subjects

J Brossmann

Publications and source records attributed to J Brossmann.

At least 37 records · Page 2Linked to original sources

PubMed2001

Mechanical thrombectomy of major and massive pulmonary embolism with use of the Amplatz thrombectomy device.

RATIONALE AND OBJECTIVES: To evaluate the feasibility of mechanical thrombectomy with the Amplatz thrombectomy device (ATD) in restoring patency of acutely thrombosed pulmonary arteries resulting from pulmonary embolism for the improvement of patient outcome. METHODS: Mechanical thrombectomy with the ATD (8F) was performed in nine consecutive patients with angiographically documented thrombus in the left or right pulmonary artery resulting from deep vein thrombosis (n = 4) or unknown cause (n = 5). RESULTS: The Miller index decreased from 18 to 11. In all patients, the majority of the thrombus in the pulmonary artery was cleared after a mean activation time of the ATD of 367 seconds. Thrombectomy was performed with the ATD alone (n = 4) or with additional long-term fibrinolysis therapy (n = 5) with infusion of recombinant tissue-type plasminogen activator. Pulmonary arterial pressure decreased from a mean of 57 mm Hg before mechanical thrombectomy to 55 mm Hg directly after the procedure and to 39 mm Hg after termination of the recombinant tissue-type plasminogen activator infusion. CONCLUSIONS: Mechanical thrombectomy with the ATD in patients with minor and major pulmonary embolism is technically feasible and safe. It is a potential alternative to drug-mediated thrombolysis and surgery. However, the incremental benefit of the ATD over conventional treatments could be shown only in a randomized controlled study.

Acute Disease↗

PubMed2001

Assessment of the position of the distal portion of the ulna in lateral projection radiographs of the wrist: analysis of the influence of pronation-supination and flexion-extension on the pisoscaphoid and the ulnotriquetral distances: a cadaver study.

RATIONALE AND OBJECTIVES: Accurate assessment of the distal radioulnar joint is of paramount importance for the detection of possible dislocation or subluxation. Using a cadaveric model, the authors attempted to establish a quantitative method that would allow identification of normal and abnormal distal radioulnar joint anatomy on well-positioned and rotated conventional radiographs. METHODS: Four cadaveric wrists, in which subsequent sectioning confirmed the absence of disease, and one cadaveric wrist with a circumscribed lesion of the triangular fibrocartilaginous complex were studied. Defined movements in flexion and extension (+/- 10 degrees, 20 degrees, 30 degrees ) and in pronation and supination (+/- 10 degrees, 20 degrees, 30 degrees ) as well as combined flexion/extension and pronation/supination were performed. The ulnotriquetral and the pisoscaphoid distances were assessed in each position. Correlation with cryosections was achieved. RESULTS: A strong linear correlation between the degree of pronation or supination and the pisoscaphoid and ulnotriquetral distances was noted. Flexion and extension produced no significant effect on the pisoscaphoid distance, but a defined shift of the ulnotriquetral distance occurred with increasing flexion and extension. CONCLUSIONS: If all parameters are taken into account, this correlation aids in estimating the degree of possible malpositioning of the wrist during radiography and the degree of subluxation of the distal radioulnar joint. Tabular data with parameters to correct for instances of malrotated images and to estimate the extent of dislocation or malrotation of the distal radioulnar joint are provided.

Cadaver↗

PubMed2001

Shell osteochondral allografts of the knee: comparison of mr imaging findings and immunologic responses.

PURPOSE: To define the magnetic resonance (MR) imaging appearance of shell osteochondral allografts of the knee and compare the MR findings with antibody responses. MATERIALS AND METHODS: Thirty-six grafts were evaluated with a 1.5-T unit with T1-, intermediate-, and T2-weighted, and three-dimensional spoiled gradient-recalled MR imaging at 3, 6, 12, 24, and/or 36 months after surgery. Nineteen patients underwent imaging serially. Two osteoradiologists scored by consensus host marrow edema, thickness of graft-host interface, signal intensity of graft marrow, cyst formation, joint effusion, articular cartilage defects, and surface collapse. Patients were divided into antibody-positive (AP) (n = 11) and antibody-negative (AN) (n = 25) groups evenly distributed across the different time points on the basis of results of anti-human leukocyte antigen antibody screening. MR findings for the two groups were compared. RESULTS: AP patients demonstrated greater mean edema (P<.002), thicker interface (P<.03), and more abnormal graft marrow (P<.04) than AN patients, and they had a higher proportion of surface collapse (P<.03). CONCLUSION: Humoral immune responses were associated with more inflammation and less complete incorporation after allograft placement. MR imaging shows promise as a surrogate biomarker for success of shell osteochondral allograft implantation.

Adolescent↗

PubMed2001

Polydioxanone biodegradable pins in the knee: MR imaging.

OBJECTIVE: Biodegradable solid implants have been developed as an alternative to metallic orthopedic fixation. In animal models, implants degrade within and are replaced by bone. This study documents the resorption of these devices in human patients with MR imaging. SUBJECTS AND METHODS: One hundred seventy-five 1.3-mm biodegradable pins made of polydioxanone were used to secure a total of 59 osteochondral allografts of the knee. Patients with the pins underwent scanning on a 1.5-T unit with 3.3- to 4-mm contiguous T1-weighted spin-echo (TR/TE, 600/15), fat-saturated proton density-weighted (3000/40), T2-weighted fast spin-echo (3000/63), and three-dimensional spoiled gradient-recalled (47/7; flip angle, 60 degrees ) sequences at 3, 6, 12, 24, or 36 months after surgery. Eighty-nine pins were imaged on multiple occasions. Two osteoradiologists interpreted the MR examinations. RESULTS: More than 80% of the pin channels were visible at 3 and at 6 months after surgery. By 24 months, only 20% of the pin channels were visible, with the remainder having been replaced by bone. At 3 months, nearly 40% of the pins were associated with adjacent marrow edema. Edema generally diminished, involving less than 20% of pins at later time points. Focal cartilage defects were evident at 32% of the pin insertion sites during the first 6 months, but these defects were present in only 4% of the insertion sites thereafter. CONCLUSION: Biodegradable polydioxanone pins usually resorb completely by 24 months. Marrow edema, presumably representing inflammation related to pin resorption, is infrequent and tends to resolve. Cartilage defects related to pin placement heal spontaneously.

Absorbable Implants↗

PubMed2000

[Mid-term follow-up after placement of the new balloon-expendable VIP-stent into the iliac arteries].

PURPOSE: To assess the effectiveness and mid-term patency of VIP balloon expandable stents in patients with iliac occlusive disease. MATERIAL AND METHODS: Between August and December 1997, 26 balloon-expandable VIP (Medtronic) stainless steel vascular stents were implanted in 19 patients with iliac occlusive disease. 22 lesions in common iliac (n = 11), external iliac (n = 5), common iliac plus contralateral external iliac (n = 1), and unilateral common and external iliac (n = 2) arteries were stented, allowing 20 limbs for assessment. There were 18 stenoses and 4 occlusions in 7 female and 12 male patients (mean age 65 years, range 45-80). RESULTS: All lesions were treated satisfactorily, yielding a technical success rate of 100%. Primary patency was 91% (20/22) at 6 months. In 2 lesions restenoses (90% and 70%) were observed, requiring repeated angioplasty. Color Doppler analysis at 12 months revealed no further restenoses. CONCLUSION: The new VIP balloon-expandable stents achieve very good initial technical success and good mid-term patency in the treatment of iliac occlusive disease.

Aged↗

PubMed2000

[First results after implantation of the new balloon-expanded Bridge-Stent into the iliac artery].

PURPOSE: To determine the success and patency rates of the new, balloon-expandable Bridge-stents for treatment of occlusions and stenoses of iliac arteries. MATERIAL AND METHODS: Between April and October 1999, 21 patients suffering from peripheral arterial occlusive disease were treated (22 lesions). In 20 cases high-grade stenoses and in two cases complete occlusions were treated. 23 balloon-expandable Bridge-stents were implanted in the common iliac (n = 16) and the external iliac (n = 6) artery after percutaneous transluminal angioplasty. RESULTS: All interventions were performed with technical success. The mean ankle-brachial index (ABI) increased from 0.7 +/- 0.19 before to 0.86 +/- 0.16 at 24 hours after the procedure (Rutherford +3 [n = 18] and +2 [n = 3]); the ABI measured after 6 months was 0.89 +/- 0.16. The primary cumulative patency rate amounted to 91% (20/22) at 6 months. In two cases restenosis of 75% were observed, requiring repeated angioplasty. CONCLUSION: The new balloon-expandable Bridge-stents achieve very good initial technical success and promising short-term patency in the percutaneous treatment of iliac occlusive disease.

Adult↗

PubMed2000

[Quantification of fluid flow in magnetic resonance tomography: an experimental study of a flow model and liquid flow measurements in the cerebral aqueduct in volunteers].

PURPOSE: To study the feasibility o MRI for quantification of fluid flow in a tube model and the cerebral aqueduct (CA) in volunteers. VOLUNTEERS AND METHODS: All studies were performed on a 1.5 T MR scanner using a head coil and a FLASH 2D phase contrast sequence with a velocity encoding at 20 cm/s. Flow (real value, ml/sec) of a saline fluid was measured in a flexible tube model with different inside diameters: 0.75-3 mm. Three flow velocities were given (normal value). To test the reproducibility, three studies were done using a flow of 0.12 or 0.14 ml/sec and a tube diameter of 0.75 and 2.0 mm. The ratio of normal to real flow value was calculated (ideal ratio = 1). MRI of CA and flow quantification was done in 24 volunteers (28 +/- 4 years). RESULTS: Using tubes with a diameter of 0.75 and 1.5 mm the real flow was sometimes higher than the velocity encoding of the phase contrast sequences. Because of this measurements of the fluid flow and the flow velocities were impossible. There was agreement for fluid flow quantification in the tube of 3.0 mm and high agreement in the tube of 2.0 mm in diameter with reproducible results. The mean diameter of the CA in normal subjects was 2.0 +/- 0.3 mm, the mean cerebral flow was 0.04 +/- 0.02 ml/sec and the peak velocity 3.06 +/- 1.59 cm/sec. CONCLUSIONS: Reliable flow quantification with MRI is feasible if the diameter of the lumen is greater than 1.5 mm, and if the flow velocity is lower than the velocity encoding. In cases of smaller diameters and higher flow velocities the velocity encoding has to be changed. Because of this the quantification seems to be inaccurate in cases of aqueductal stenosis with the method we used.

Adult↗

PubMed2000

Analysis of patellar cartilage. Comparison of conventional MR imaging and MR and CT arthrography in cadavers.

OBJECTIVE: To compare the sensitivity of conventional MR sequences, MR arthrography, and CT arthrography for the detection of cartilage lesions of the patella in cadavers. MATERIAL AND METHODS: Cartilage lesions in 10 cadaveric specimens were evaluated by MR imaging, including T1-weighted, proton density-weighted and T2-weighted sequences, and fat-suppressed spoiled gradient recalled acquisition in the steady state (SPGR), MR arthrography including T1-weighted and SPGR sequences, and double-contrast CT arthrography including conventional and subtracted images. The sensitivities with regard to detection of lesions were compared to results from morphologic and histologic investigations of sectioned specimens. RESULTS: Twenty-one lesions were detected morphologically. For the detection of these lesions, sensitivities were as follows: T1-weighted images 33.3%; proton density-weighted images 85.7%; T2-weighted images 85.7%; SPGR images 80.9%; MR arthrography with T1-SE sequences 57.1%; MR arthrography with SPGR sequence 90.5%; and CT arthrography, both regular and subtracted images 85.7%. CONCLUSION: For noninvasive techniques, T2-weighted images revealed the highest sensitivity for the detection of patellar cartilage lesions, which was surpassed only by MR arthrography using the SPGR sequence. CT arthrography delineated surface irregularities but failed to demonstrate intrachondral lesions.

Aged↗

PubMed2000

Magnetic resonance arthrography of the acetabular labrum. Macroscopic and histological correlation in 20 cadavers.

We studied the sensitivity and specificity of magnetic resonance arthrography (MRa) for the diagnosis of lesions of the acetabular labrum in 20 cadaver hips. The MRa results were compared with macroscopic and histological findings. We found that the labrum could be satisfactorily delineated by MRa and that large detachments could be identified satisfactorily. The diagnosis of small detachments and degeneration of the labrum was less reliable.

Acetabulum↗

PubMed1999

Percutaneous introducibility of the expandable vascular sheath system and injury potential of balloon-assisted thrombectomy: preliminary In vivo results.

PURPOSE: To test the percutaneous introducibility of the expandable vascular sheath (EVS) system and the safety of percutaneous balloon-assisted thrombectomy. METHODS: The EVS was inserted directly (n = 9) or through a 9.5 Fr regular vascular introducer sheath (n = 9) into the femoral arteries and veins and carotid arteries in four dogs (18-21 kg). Balloon-assisted thrombectomies were simulated in iliac arteries. Histologic examinations were done at sites of funnel deployment immediately (n = 4) and 25 days (n = 8) after the intervention. RESULTS: The EVS was successfully introduced into six of nine vessels by a direct percutaneous approach. Balloon-assisted thrombectomy using the EVS device caused localized intimal denudation, disruption of the internal elastic lamina, and mild hemorrhages into the media; one arterial dissection at the site of funnel deployment was seen. All indirect insertions and funnel deployments were successful. Twenty-five days after the experiments, intimal hyperplasia was noted in all cases. CONCLUSION: Percutaneous balloon-assisted thrombectomy may cause mild vascular injuries. Direct percutaneous introduction of the EVS device cannot be recommended yet.

Animals↗

PubMed1999

MR imaging of musculoskeletal trauma to the pelvis and the lower limb.

Magnetic resonance imaging can be used in the trauma setting to detect fractures and associated soft tissue injuries of the musculoskeletal system. Magnetic resonance imaging complements plain radiography and CT for evaluating cancellous bone, cartilage and growth-plate injuries, and intra- and extraarticular supporting soft tissue structures. This review outlines typical applications and imaging consideration for injuries of the pelvis and lower extremity.

Bone and Bones↗

PubMed1999

Kinematic CT and MR imaging of the patellofemoral joint.

Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 degrees and 30 degrees of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions.

Arthralgia↗

PubMed1999

[MR arthrography of the labrum acetabulare--a radiological-anatomical correlation in 20 cadaveric hips].

PURPOSE: To investigate frequency of acetabular labral lesions in elderly hip joints, and to determine sensitivity and specificity of MR arthrography (MRa) for the detection of these abnormalities. MATERIALS AND METHODS: Twenty cadaveric hip joints were examined by MRa. For MRa, 15 ml of a solution of iodinated contrast solution (Solutrast 300) and Gd-DTPA (100:1) were injected under fluoroscopic guidance. MR imaging was performed on a 1.5 T MR scanner (Vision, Siemens; FOV 16 cm, matrix 256 x 256, fat-suppressed 3D-FLASH). Multiplanar image reconstructions were done perpendicular to the acetabulum in the oblique-coronal, oblique-axial, and radial planes. The labral specimens were examined macroscopically. RESULTS: In 12/20 hips (60%), a labral lesion was found on pathologic examination. In 7 specimens, the labrum was partially or completely detached in the weight-bearing superior region. One flap-like variant of the labrum was seen; in 4 hip joints, the labrum was degenerated (one cystic degeneration). Pathologic findings were confirmed by MRa in 8/12 specimens (sensitivity 67%). All degenerated labra were correctly diagnosed on MRa. Three small labral detachments and the flap-like variant were misinterpreted as being normal. There were no false positive findings (specificity 100%). The accuracy was 80%. Labral lesions were seen in 6/8 and in 6/12 of hips with and without osteoarthritis, respectively. CONCLUSION: MRa is well suited to delineate the acetabular labrum and to diagnose labral abnormalities. Detection of small labral detachments and anatomic variants is difficult and requires some experience. Labral lesions are correlated to osteoarthritis of the hip, but may be frequently seen in the elderly without underlying osteoarthritis.

Acetabulum↗

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

[Pelvic ring injuries].

PURPOSE: Analysis of the trauma patient of fractures of the pelvic ring and classification according to AO/Tile. METHODS: 125 unselected patients (43 females, 82 males) were evaluated retrospectively by conventional x-ray, and CT examinations included follow-studies. RESULTS: Type-A fractures were seen in 36 (29%), Type-B fractures in 58 (46%), and Type-C fractures in 31 (25%) cases. Type-B and Type-C fractures mainly occurred in patients with traffic accidents and falls from great height. Type-A fractures were seen most often in patients with accidents at home or at work. However, in patients with complex fractures a classification concerning Type-B or Type-C fractures was difficult. SUMMARY: Based on CT criterias, in most patients a statement concerning the applied forces, the stability of the pelvic rim and the fracture type can be made.

Fractures, Bone↗

PubMed1998

Update on imaging of orthopedic infections.

Although the diagnosis of infection is only a small part of the orthopedist's job description, it is a important part. This article discusses the fundamentals of orthopedic infections and highlights the refinements on this topic from a radiologic perspective. In addition to reviewing the imaging appearance of musculoskeletal infections in bone and the surrounding soft tissues, we focus on the advantages and disadvantages of five imaging methods: radiography, sonography, CT, scintigraphy, and MR imaging. Finally, we review three specific situations that have garnered substantial attention in recent medical literature: chronic recurrent multifocal osteomyelitis, musculoskeletal infections in AIDS patients, and pedal infections in diabetic patients.

Diabetic Foot↗

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

[The imaging of hamate fractures in the conventional X-ray and CT: experimental results and clinical experiences].

PURPOSE: Examination of the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and HR-CT. MATERIAL AND METHODS: In an in vitro experiment on 18 cadaver hands, the hamate bone was fractured at different localisations. Before and after fracture, conventional x-rays were taken in different projectional planes: a.-p., lateral, oblique and carpal tunnel view, as well as an HR-CT with 2 mm layer thickness in the axial, sagittal and coronal plane. In addition, 15 clinically verified hamate bone fractures (two body and 13 hook of hamate fractures) were reviewed retrospectively to assess the value of the imaging procedures that led to diagnosis. RESULTS: Taking into account all conventional x-ray projections applied, the in vitro experiment yielded a sensitivity of 72.2%, a specificity of 88.8% and an accuracy of 80.5%. For CT, the sensitivity was 100%, the specificity 94.4% and the accuracy 97.2%. In retrospective clinical evaluation, 60% of the existing fractures were identified in the conventional x-ray images. The remaining fractures were detected by additional procedures like scintigraphy, conventional tomography and CT. CONCLUSION: For the diagnosis of fractures of the body and hook of the hamate HR-CT is the imaging procedure of choice, in which case an axial or sagittal plane should be chosen.

Adult↗